// {
// $1 = new std::string( PyString_AsString( $input ) );
// }
-//
-add a note on the rename that works !
+// add a note on the rename that works !
// void Junk();
// void Junk(std::string const & bozo);
//
#-----------------------------------------------------------------------------
# Build jpeg lib first:
-SUBDIRS(jpeg)
+SUBDIRS(gdcmjpeg)
# "jpeglib.h" is defined here:
INCLUDE_DIRECTORIES(
${GDCM_SOURCE_DIR}/src
${GDCM_BINARY_DIR}/ #for gdcmConfigure.h
+ ${GDCM_BINARY_DIR}/src #for gdcmjpeg 8, 12 and 16
)
SET(libgdcm_la_SOURCES
ADD_LIBRARY(gdcm ${libgdcm_la_SOURCES} )
IF(UNIX)
TARGET_LINK_LIBRARIES(gdcm
- gdcmijpeg8
- gdcmijpeg12
- gdcmijpeg16
+ gdcmjpeg8
+ gdcmjpeg12
+ gdcmjpeg16
)
ELSE(UNIX)
TARGET_LINK_LIBRARIES(gdcm
- gdcmijpeg8
- gdcmijpeg12
- gdcmijpeg16
+ gdcmjpeg8
+ gdcmjpeg12
+ gdcmjpeg16
Wsock32.lib #doesn't exist on cygwin
)
ENDIF(UNIX)
Program: gdcm
Module: $RCSfile: gdcmJpeg12.cxx,v $
Language: C++
- Date: $Date: 2004/10/22 03:05:42 $
- Version: $Revision: 1.23 $
+ Date: $Date: 2004/11/07 14:28:55 $
+ Version: $Revision: 1.24 $
Copyright (c) CREATIS (Centre de Recherche et d'Applications en Traitement de
l'Image). All rights reserved. See Doc/License.txt or
#include "gdcmFile.h"
extern "C" {
-#include "src/jpeg/libijg12/jconfig.h"
-#include "src/jpeg/libijg12/jpeglib.h"
-#include "src/jpeg/libijg12/jinclude.h"
-#include "src/jpeg/libijg12/jerror.h"
+#include "gdcmjpeg/12/jinclude.h"
+#include "gdcmjpeg/12/jpeglib.h"
}
-
#define gdcm_write_JPEG_file gdcm_write_JPEG_file12
#define gdcm_read_JPEG_file gdcm_read_JPEG_file12
Program: gdcm
Module: $RCSfile: gdcmJpeg16.cxx,v $
Language: C++
- Date: $Date: 2004/10/22 03:05:42 $
- Version: $Revision: 1.2 $
+ Date: $Date: 2004/11/07 14:28:55 $
+ Version: $Revision: 1.3 $
Copyright (c) CREATIS (Centre de Recherche et d'Applications en Traitement de
l'Image). All rights reserved. See Doc/License.txt or
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
-
#include "gdcmFile.h"
extern "C" {
-#include "src/jpeg/libijg16/jconfig.h"
-#include "src/jpeg/libijg16/jpeglib.h"
-#include "src/jpeg/libijg16/jinclude.h"
-#include "src/jpeg/libijg16/jerror.h"
+#include "gdcmjpeg/16/jinclude.h"
+#include "gdcmjpeg/16/jpeglib.h"
}
-
#define gdcm_write_JPEG_file gdcm_write_JPEG_file16
#define gdcm_read_JPEG_file gdcm_read_JPEG_file16
Program: gdcm
Module: $RCSfile: gdcmJpeg8.cxx,v $
Language: C++
- Date: $Date: 2004/10/22 03:05:42 $
- Version: $Revision: 1.9 $
+ Date: $Date: 2004/11/07 14:28:55 $
+ Version: $Revision: 1.10 $
Copyright (c) CREATIS (Centre de Recherche et d'Applications en Traitement de
l'Image). All rights reserved. See Doc/License.txt or
#include "gdcmFile.h"
extern "C" {
-#include "src/jpeg/libijg8/jconfig.h"
-#include "src/jpeg/libijg8/jpeglib.h"
-#include "src/jpeg/libijg8/jinclude.h"
-#include "src/jpeg/libijg8/jerror.h"
+#include "gdcmjpeg/8/jconfig.h"
+#include "gdcmjpeg/8/jpeglib.h"
}
#define gdcm_write_JPEG_file gdcm_write_JPEG_file8
--- /dev/null
+# JPEG 12 bits project
+
+INCLUDE_DIRECTORIES(
+ "${CMAKE_CURRENT_BINARY_DIR}"
+ "${GDCMJPEG_SOURCE_DIR}")
+ADD_LIBRARY(gdcmjpeg12 ${JPEG_SOURCES})
+INSTALL_TARGETS(/lib/ gdcmjpeg12)
+
+
--- /dev/null
+# JPEG 16 bits project
+
+INCLUDE_DIRECTORIES(
+ "${CMAKE_CURRENT_BINARY_DIR}"
+ "${GDCMJPEG_SOURCE_DIR}")
+ADD_LIBRARY(gdcmjpeg16 ${JPEG_SOURCES})
+INSTALL_TARGETS(/lib/ gdcmjpeg16)
+
+
--- /dev/null
+# JPEG 8 bits project
+
+INCLUDE_DIRECTORIES(
+ "${CMAKE_CURRENT_BINARY_DIR}"
+ "${GDCMJPEG_SOURCE_DIR}")
+ADD_LIBRARY(gdcmjpeg8 ${JPEG_SOURCES})
+INSTALL_TARGETS(/lib/ gdcmjpeg8)
+
--- /dev/null
+PROJECT(GDCMJPEG)
+
+INCLUDE_REGULAR_EXPRESSION("^(jchuff|jconfig|jdct|jdhuff|jerror|jinclude|jmemsys|jmorecfg|jpegint|jpeglib|jversion|jpeg).*$")
+
+# memmgr back ends: compile only one of these into a working library
+# (For now, let's use the mode that requires the image fit into memory.
+# This is the recommended mode for Win32 anyway.)
+SET(systemdependent_SRCS jmemnobs.c)
+
+# library object files common to compression and decompression
+SET(common_SRCS
+jcomapi.c jutils.c jerror.c jmemmgr.c
+)
+
+# compression library object files
+SET(compression_SRCS
+jcapimin.c jcapistd.c jctrans.c jcparam.c jcinit.c
+jcmaster.c jcmarker.c jcmainct.c jcprepct.c jccoefct.c jccolor.c
+jcsample.c jchuff.c jcphuff.c jcdctmgr.c jfdctfst.c jfdctflt.c
+jdatadst.c
+)
+
+# Lossy (DCT) codec:
+SET(comp_lossy_SRCS
+jfdctint.c
+jclossy.c
+
+# lossless
+jclossls.c
+
+jdarith.c
+jcodec.c
+jcscale.c
+jcshuff.c
+jclhuff.c
+jcpred.c
+jcdiffct.c
+)
+
+# decompression library object files
+SET(decompression_SRCS
+jdapimin.c jdapistd.c jdtrans.c jdmaster.c
+jdinput.c jdmarker.c jdhuff.c jdphuff.c jdmainct.c jdcoefct.c
+jdpostct.c jddctmgr.c jidctfst.c jidctflt.c jidctint.c jidctred.c
+jdsample.c jdcolor.c jquant1.c jquant2.c jdmerge.c
+jdatasrc.c
+)
+
+SET(decomp_lossy_SRCS
+ jdlossls.c jdlossy.c
+jcarith.c
+jdlhuff.c
+jddiffct.c
+jdpred.c
+jdscale.c
+jdshuff.c
+)
+
+SET(JPEG_HEADER_FILES
+ jchuff.h
+ jdct.h
+ jdhuff.h
+ jerror.h
+ jinclude.h
+ jmemsys.h
+# jmorecfg.h #this one need to be configured
+ jpegint.h
+ jpeglib.h
+ jversion.h
+ jlossy.h
+ jlossls.h
+ )
+
+SET(JPEG_SOURCES)
+FOREACH(src
+ ${systemdependent_SRCS}
+ ${common_SRCS}
+ ${compression_SRCS}
+ ${decompression_SRCS}
+ ${comp_lossy_SRCS}
+ ${decomp_lossy_SRCS}
+ )
+ SET(JPEG_SOURCES ${JPEG_SOURCES}
+ "${GDCMJPEG_SOURCE_DIR}/${src}")
+ENDFOREACH(src)
+
+IF (WIN32)
+ IF (BUILD_SHARED_LIBS)
+ ADD_DEFINITIONS(-DJPEGDLL)
+ ELSE (BUILD_SHARED_LIBS)
+ ADD_DEFINITIONS(-DJPEGSTATIC)
+ ENDIF (BUILD_SHARED_LIBS)
+ENDIF (WIN32)
+
+CONFIGURE_FILE(${GDCMJPEG_SOURCE_DIR}/.NoDartCoverage
+ ${GDCMJPEG_BINARY_DIR}/.NoDartCoverage)
+
+# Generate three libraries: jpeg 8bits, 12bits and 16bits
+# using only one source directory
+
+# Particular case jmorecfg.h needs to be specified either 8, 12 or 16 bits:
+FOREACH(bits 8 12 16)
+ SET(CMAKE_BITS_IN_JSAMPLE ${bits})
+ CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/jmorecfg.h.in
+ ${CMAKE_CURRENT_BINARY_DIR}/${bits}/jmorecfg.h @ONLY IMMEDIATE)
+ SET(BITS_TYPE_JPEG_MANGLE_NAME "gdcmjpeg/mangle_jpeg${bits}bits.h")
+ CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/jconfig.h.in
+ ${CMAKE_CURRENT_BINARY_DIR}/${bits}/jconfig.h @ONLY IMMEDIATE)
+ # Dummy copy for GDCM to include <gdcmjpeg/8/jpeglib.h> with no conflict
+ CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/jpeglib.h
+ ${CMAKE_CURRENT_BINARY_DIR}/${bits}/jpeglib.h COPYONLY IMMEDIATE)
+ CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/jerror.h
+ ${CMAKE_CURRENT_BINARY_DIR}/${bits}/jerror.h COPYONLY IMMEDIATE)
+ CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/jinclude.h
+ ${CMAKE_CURRENT_BINARY_DIR}/${bits}/jinclude.h COPYONLY IMMEDIATE)
+ENDFOREACH(bits)
+
+SUBDIRS(8 12 16)
+
--- /dev/null
+
+COPYRIGHT
+
+Unless otherwise specified, the DCMTK software package has the
+following copyright:
+
+/*
+ * Copyright (C) 1994-2004, OFFIS
+ *
+ * This software and supporting documentation were developed by
+ *
+ * Kuratorium OFFIS e.V.
+ * Healthcare Information and Communication Systems
+ * Escherweg 2
+ * D-26121 Oldenburg, Germany
+ *
+ * THIS SOFTWARE IS MADE AVAILABLE, AS IS, AND OFFIS MAKES NO WARRANTY
+ * REGARDING THE SOFTWARE, ITS PERFORMANCE, ITS MERCHANTABILITY OR
+ * FITNESS FOR ANY PARTICULAR USE, FREEDOM FROM ANY COMPUTER DISEASES OR
+ * ITS CONFORMITY TO ANY SPECIFICATION. THE ENTIRE RISK AS TO QUALITY AND
+ * PERFORMANCE OF THE SOFTWARE IS WITH THE USER.
+ *
+ * Copyright of the software and supporting documentation is, unless
+ * otherwise stated, owned by OFFIS, and free access is hereby granted as
+ * a license to use this software, copy this software and prepare
+ * derivative works based upon this software. However, any distribution
+ * of this software source code or supporting documentation or derivative
+ * works (source code and supporting documentation) must include the
+ * three paragraphs of this copyright notice.
+ *
+ */
+
+Some portions of the DCMTK software package are derived from earlier
+versions of this software with the following copyright, and can be
+identifed by the following copyright notice located in each source file:
+
+/*
+ * Copyright (C) 1993/1994, OFFIS, Oldenburg University and CERIUM
+ *
+ * This software and supporting documentation were
+ * developed by
+ *
+ * Institut OFFIS
+ * Bereich Kommunikationssysteme
+ * Westerstr. 10-12
+ * 26121 Oldenburg, Germany
+ *
+ * Fachbereich Informatik
+ * Abteilung Prozessinformatik
+ * Carl von Ossietzky Universitaet Oldenburg
+ * Ammerlaender Heerstr. 114-118
+ * 26111 Oldenburg, Germany
+ *
+ * CERIUM
+ * Laboratoire SIM
+ * Faculte de Medecine
+ * 2 Avenue du Pr. Leon Bernard
+ * 35043 Rennes Cedex, France
+ *
+ * for CEN/TC251/WG4 as a contribution to the Radiological
+ * Society of North America (RSNA) 1993 Digital Imaging and
+ * Communications in Medicine (DICOM) Demonstration.
+ *
+ * THIS SOFTWARE IS MADE AVAILABLE, AS IS, AND NEITHER OFFIS,
+ * OLDENBURG UNIVERSITY NOR CERIUM MAKE ANY WARRANTY REGARDING
+ * THE SOFTWARE, ITS PERFORMANCE, ITS MERCHANTABILITY OR
+ * FITNESS FOR ANY PARTICULAR USE, FREEDOM FROM ANY COMPUTER
+ * DISEASES OR ITS CONFORMITY TO ANY SPECIFICATION. THE
+ * ENTIRE RISK AS TO QUALITY AND PERFORMANCE OF THE SOFTWARE
+ * IS WITH THE USER.
+ *
+ * Copyright of the software and supporting documentation
+ * is, unless otherwise stated, jointly owned by OFFIS,
+ * Oldenburg University and CERIUM and free access is hereby
+ * granted as a license to use this software, copy this
+ * software and prepare derivative works based upon this
+ * software. However, any distribution of this software
+ * source code or supporting documentation or derivative
+ * works (source code and supporting documentation) must
+ * include the three paragraphs of this copyright notice.
+ *
+ */
+
+Some other parts of this software within the dcmtk/dcmnet
+sub-package related to the DICOM Upper Layer Protocol are
+derived from software developed for the RSNA'93 DICOM
+demonstration and kindly made available to us by the Mallinckrodt
+Institute of Radiology. Such software can be identifed by the
+following copyright notice located in each affected source file:
+
+/*
+ * Copyright (C) 1993, RSNA and Washington University
+ *
+ * The software and supporting documentation for the Radiological
+ * Society of North America (RSNA) 1993 Digital Imaging and
+ * Communications in Medicine (DICOM) Demonstration were developed
+ * at the
+ * Electronic Radiology Laboratory
+ * Mallinckrodt Institute of Radiology
+ * Washington University School of Medicine
+ * 510 S. Kingshighway Blvd.
+ * St. Louis, MO 63110
+ * as part of the 1993 DICOM Central Test Node project for, and
+ * under contract with, the Radiological Society of North America.
+ *
+ * THIS SOFTWARE IS MADE AVAILABLE, AS IS, AND NEITHER RSNA NOR
+ * WASHINGTON UNIVERSITY MAKE ANY WARRANTY ABOUT THE SOFTWARE, ITS
+ * PERFORMANCE, ITS MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR
+ * USE, FREEDOM FROM ANY COMPUTER DISEASES OR ITS CONFORMITY TO ANY
+ * SPECIFICATION. THE ENTIRE RISK AS TO QUALITY AND PERFORMANCE OF
+ * THE SOFTWARE IS WITH THE USER.
+ *
+ * Copyright of the software and supporting documentation is
+ * jointly owned by RSNA and Washington University, and free access
+ * is hereby granted as a license to use this software, copy this
+ * software and prepare derivative works based upon this software.
+ * However, any distribution of this software source code or
+ * supporting documentation or derivative works (source code and
+ * supporting documentation) must include the three paragraphs of
+ * the copyright notice.
+ */
+
+The dcmjpeg sub-package includes an adapted version of the Independent JPEG
+Group Toolkit Version 6b, which is contained in dcmjpeg/libijg8,
+dcmjpeg/libijg12 and dcmjpeg/libijg16. This toolkit is covered by the
+following copyright. The original README file for the Independent JPEG
+Group Toolkit is located in dcmjpeg/docs/ijg_readme.txt.
+
+/*
+ * The authors make NO WARRANTY or representation, either express or implied,
+ * with respect to this software, its quality, accuracy, merchantability, or
+ * fitness for a particular purpose. This software is provided "AS IS", and you,
+ * its user, assume the entire risk as to its quality and accuracy.
+ *
+ * This software is copyright (C) 1991-1998, Thomas G. Lane.
+ * All Rights Reserved except as specified below.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute this
+ * software (or portions thereof) for any purpose, without fee, subject to these
+ * conditions:
+ * (1) If any part of the source code for this software is distributed, then this
+ * README file must be included, with this copyright and no-warranty notice
+ * unaltered; and any additions, deletions, or changes to the original files
+ * must be clearly indicated in accompanying documentation.
+ * (2) If only executable code is distributed, then the accompanying
+ * documentation must state that "this software is based in part on the work of
+ * the Independent JPEG Group".
+ * (3) Permission for use of this software is granted only if the user accepts
+ * full responsibility for any undesirable consequences; the authors accept
+ * NO LIABILITY for damages of any kind.
+ *
+ * These conditions apply to any software derived from or based on the IJG code,
+ * not just to the unmodified library. If you use our work, you ought to
+ * acknowledge us.
+ *
+ * Permission is NOT granted for the use of any IJG author's name or company name
+ * in advertising or publicity relating to this software or products derived from
+ * it. This software may be referred to only as "the Independent JPEG Group's
+ * software".
+ *
+ * We specifically permit and encourage the use of this software as the basis of
+ * commercial products, provided that all warranty or liability claims are
+ * assumed by the product vendor.
+ */
+
+
+The color quantization code in module dcmimage (dcmquant and the related
+classes) is derived from code written by Jef Poskanzer for the NetPBM
+toolkit which has the following copyright:
+
+/*
+ * Copyright (C) 1989, 1991 by Jef Poskanzer.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for any purpose and without fee is hereby granted, provided
+ * that the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation. This software is provided "as is" without express or
+ * implied warranty.
+ */
+
+
+The code for the OFStandard::strlcpy and OFStandard::strlcat helper
+functions in ofstd/libsrc/ofstd.cc has been derived from the BSD
+implementation of strlcpy() and strlcat() and which carries the
+following copyright notice:
+
+/*
+ * Copyright (c) 1998 Todd C. Miller <Todd.Miller(at)courtesan.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+The code for the OFStandard::atof helper function in
+ofstd/libsrc/ofstd.cc has been derived from an implementation which
+carries the following copyright notice:
+
+/*
+ * Copyright 1988 Regents of the University of California
+ * Permission to use, copy, modify, and distribute this software and
+ * its documentation for any purpose and without fee is hereby granted,
+ * provided that the above copyright notice appear in all copies. The
+ * University of California makes no representations about the
+ * suitability of this software for any purpose. It is provided "as
+ * is" without express or implied warranty.
+ *
+ *
+ * The code for OFStandard::ftoa has been derived
+ * from an implementation which carries the following copyright notice:
+ *
+ * Copyright (c) 1988 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley. The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+The "Base64" encoder/decoder in ofstd/libsrc/ofstd.cc has been derived
+from an implementation which carries the following copyright notice:
+
+/*
+ * Copyright (c) 1999, Bob Withers - bwit(at)pobox.com
+ *
+ * This code may be freely used for any purpose, either personal or commercial,
+ * provided the authors copyright notice remains intact.
+ */
+
--- /dev/null
+The Independent JPEG Group's JPEG software
+==========================================
+
+README for release 6b of 27-Mar-1998
+====================================
+
+This distribution contains the sixth public release of the Independent JPEG
+Group's free JPEG software. You are welcome to redistribute this software and
+to use it for any purpose, subject to the conditions under LEGAL ISSUES, below.
+
+Serious users of this software (particularly those incorporating it into
+larger programs) should contact IJG at jpeg-info@uunet.uu.net to be added to
+our electronic mailing list. Mailing list members are notified of updates
+and have a chance to participate in technical discussions, etc.
+
+This software is the work of Tom Lane, Philip Gladstone, Jim Boucher,
+Lee Crocker, Julian Minguillon, Luis Ortiz, George Phillips, Davide Rossi,
+Guido Vollbeding, Ge' Weijers, and other members of the Independent JPEG
+Group.
+
+IJG is not affiliated with the official ISO JPEG standards committee.
+
+
+DOCUMENTATION ROADMAP
+=====================
+
+This file contains the following sections:
+
+OVERVIEW General description of JPEG and the IJG software.
+LEGAL ISSUES Copyright, lack of warranty, terms of distribution.
+REFERENCES Where to learn more about JPEG.
+ARCHIVE LOCATIONS Where to find newer versions of this software.
+RELATED SOFTWARE Other stuff you should get.
+FILE FORMAT WARS Software *not* to get.
+TO DO Plans for future IJG releases.
+
+Other documentation files in the distribution are:
+
+User documentation:
+ install.doc How to configure and install the IJG software.
+ usage.doc Usage instructions for cjpeg, djpeg, jpegtran,
+ rdjpgcom, and wrjpgcom.
+ *.1 Unix-style man pages for programs (same info as usage.doc).
+ wizard.doc Advanced usage instructions for JPEG wizards only.
+ change.log Version-to-version change highlights.
+Programmer and internal documentation:
+ libjpeg.doc How to use the JPEG library in your own programs.
+ example.c Sample code for calling the JPEG library.
+ structure.doc Overview of the JPEG library's internal structure.
+ filelist.doc Road map of IJG files.
+ coderules.doc Coding style rules --- please read if you contribute code.
+
+Please read at least the files install.doc and usage.doc. Useful information
+can also be found in the JPEG FAQ (Frequently Asked Questions) article. See
+ARCHIVE LOCATIONS below to find out where to obtain the FAQ article.
+
+If you want to understand how the JPEG code works, we suggest reading one or
+more of the REFERENCES, then looking at the documentation files (in roughly
+the order listed) before diving into the code.
+
+
+OVERVIEW
+========
+
+This package contains C software to implement JPEG image compression and
+decompression. JPEG (pronounced "jay-peg") is a standardized compression
+method for full-color and gray-scale images. JPEG is intended for compressing
+"real-world" scenes; line drawings, cartoons and other non-realistic images
+are not its strong suit. JPEG is lossy, meaning that the output image is not
+exactly identical to the input image. Hence you must not use JPEG if you
+have to have identical output bits. However, on typical photographic images,
+very good compression levels can be obtained with no visible change, and
+remarkably high compression levels are possible if you can tolerate a
+low-quality image. For more details, see the references, or just experiment
+with various compression settings.
+
+This software implements JPEG baseline, extended-sequential, progressive
+and lossless compression processes. Provision is made for supporting all
+variants of these processes, although some uncommon parameter settings aren't
+implemented yet. For legal reasons, we are not distributing code for the
+arithmetic-coding variants of JPEG; see LEGAL ISSUES. We have made no
+provision for supporting the hierarchical processes defined in the standard.
+
+We provide a set of library routines for reading and writing JPEG image files,
+plus two sample applications "cjpeg" and "djpeg", which use the library to
+perform conversion between JPEG and some other popular image file formats.
+The library is intended to be reused in other applications.
+
+In order to support file conversion and viewing software, we have included
+considerable functionality beyond the bare JPEG coding/decoding capability;
+for example, the color quantization modules are not strictly part of JPEG
+decoding, but they are essential for output to colormapped file formats or
+colormapped displays. These extra functions can be compiled out of the
+library if not required for a particular application. We have also included
+"jpegtran", a utility for lossless transcoding between different JPEG
+processes, and "rdjpgcom" and "wrjpgcom", two simple applications for
+inserting and extracting textual comments in JFIF files.
+
+The emphasis in designing this software has been on achieving portability and
+flexibility, while also making it fast enough to be useful. In particular,
+the software is not intended to be read as a tutorial on JPEG. (See the
+REFERENCES section for introductory material.) Rather, it is intended to
+be reliable, portable, industrial-strength code. We do not claim to have
+achieved that goal in every aspect of the software, but we strive for it.
+
+We welcome the use of this software as a component of commercial products.
+No royalty is required, but we do ask for an acknowledgement in product
+documentation, as described under LEGAL ISSUES.
+
+
+LEGAL ISSUES
+============
+
+In plain English:
+
+1. We don't promise that this software works. (But if you find any bugs,
+ please let us know!)
+2. You can use this software for whatever you want. You don't have to pay us.
+3. You may not pretend that you wrote this software. If you use it in a
+ program, you must acknowledge somewhere in your documentation that
+ you've used the IJG code.
+
+In legalese:
+
+The authors make NO WARRANTY or representation, either express or implied,
+with respect to this software, its quality, accuracy, merchantability, or
+fitness for a particular purpose. This software is provided "AS IS", and you,
+its user, assume the entire risk as to its quality and accuracy.
+
+This software is copyright (C) 1991-1998, Thomas G. Lane.
+All Rights Reserved except as specified below.
+
+Permission is hereby granted to use, copy, modify, and distribute this
+software (or portions thereof) for any purpose, without fee, subject to these
+conditions:
+(1) If any part of the source code for this software is distributed, then this
+README file must be included, with this copyright and no-warranty notice
+unaltered; and any additions, deletions, or changes to the original files
+must be clearly indicated in accompanying documentation.
+(2) If only executable code is distributed, then the accompanying
+documentation must state that "this software is based in part on the work of
+the Independent JPEG Group".
+(3) Permission for use of this software is granted only if the user accepts
+full responsibility for any undesirable consequences; the authors accept
+NO LIABILITY for damages of any kind.
+
+These conditions apply to any software derived from or based on the IJG code,
+not just to the unmodified library. If you use our work, you ought to
+acknowledge us.
+
+Permission is NOT granted for the use of any IJG author's name or company name
+in advertising or publicity relating to this software or products derived from
+it. This software may be referred to only as "the Independent JPEG Group's
+software".
+
+We specifically permit and encourage the use of this software as the basis of
+commercial products, provided that all warranty or liability claims are
+assumed by the product vendor.
+
+
+ansi2knr.c is included in this distribution by permission of L. Peter Deutsch,
+sole proprietor of its copyright holder, Aladdin Enterprises of Menlo Park, CA.
+ansi2knr.c is NOT covered by the above copyright and conditions, but instead
+by the usual distribution terms of the Free Software Foundation; principally,
+that you must include source code if you redistribute it. (See the file
+ansi2knr.c for full details.) However, since ansi2knr.c is not needed as part
+of any program generated from the IJG code, this does not limit you more than
+the foregoing paragraphs do.
+
+The Unix configuration script "configure" was produced with GNU Autoconf.
+It is copyright by the Free Software Foundation but is freely distributable.
+The same holds for its supporting scripts (config.guess, config.sub,
+ltconfig, ltmain.sh). Another support script, install-sh, is copyright
+by M.I.T. but is also freely distributable.
+
+It appears that the arithmetic coding option of the JPEG spec is covered by
+patents owned by IBM, AT&T, and Mitsubishi. Hence arithmetic coding cannot
+legally be used without obtaining one or more licenses. For this reason,
+support for arithmetic coding has been removed from the free JPEG software.
+(Since arithmetic coding provides only a marginal gain over the unpatented
+Huffman mode, it is unlikely that very many implementations will support it.)
+So far as we are aware, there are no patent restrictions on the remaining
+code.
+
+The IJG distribution formerly included code to read and write GIF files.
+To avoid entanglement with the Unisys LZW patent, GIF reading support has
+been removed altogether, and the GIF writer has been simplified to produce
+"uncompressed GIFs". This technique does not use the LZW algorithm; the
+resulting GIF files are larger than usual, but are readable by all standard
+GIF decoders.
+
+We are required to state that
+ "The Graphics Interchange Format(c) is the Copyright property of
+ CompuServe Incorporated. GIF(sm) is a Service Mark property of
+ CompuServe Incorporated."
+
+
+REFERENCES
+==========
+
+We highly recommend reading one or more of these references before trying to
+understand the innards of the JPEG software.
+
+The best short technical introduction to the JPEG compression algorithm is
+ Wallace, Gregory K. "The JPEG Still Picture Compression Standard",
+ Communications of the ACM, April 1991 (vol. 34 no. 4), pp. 30-44.
+(Adjacent articles in that issue discuss MPEG motion picture compression,
+applications of JPEG, and related topics.) If you don't have the CACM issue
+handy, a PostScript file containing a revised version of Wallace's article is
+available at ftp://ftp.uu.net/graphics/jpeg/wallace.ps.gz. The file (actually
+a preprint for an article that appeared in IEEE Trans. Consumer Electronics)
+omits the sample images that appeared in CACM, but it includes corrections
+and some added material. Note: the Wallace article is copyright ACM and IEEE,
+and it may not be used for commercial purposes.
+
+A somewhat less technical, more leisurely introduction to JPEG can be found in
+"The Data Compression Book" by Mark Nelson and Jean-loup Gailly, published by
+M&T Books (New York), 2nd ed. 1996, ISBN 1-55851-434-1. This book provides
+good explanations and example C code for a multitude of compression methods
+including JPEG. It is an excellent source if you are comfortable reading C
+code but don't know much about data compression in general. The book's JPEG
+sample code is far from industrial-strength, but when you are ready to look
+at a full implementation, you've got one here...
+
+The best full description of JPEG is the textbook "JPEG Still Image Data
+Compression Standard" by William B. Pennebaker and Joan L. Mitchell, published
+by Van Nostrand Reinhold, 1993, ISBN 0-442-01272-1. Price US$59.95, 638 pp.
+The book includes the complete text of the ISO JPEG standards (DIS 10918-1
+and draft DIS 10918-2). This is by far the most complete exposition of JPEG
+in existence, and we highly recommend it.
+
+The JPEG standard itself is not available electronically; you must order a
+paper copy through ISO or ITU. (Unless you feel a need to own a certified
+official copy, we recommend buying the Pennebaker and Mitchell book instead;
+it's much cheaper and includes a great deal of useful explanatory material.)
+In the USA, copies of the standard may be ordered from ANSI Sales at (212)
+642-4900, or from Global Engineering Documents at (800) 854-7179. (ANSI
+doesn't take credit card orders, but Global does.) It's not cheap: as of
+1992, ANSI was charging $95 for Part 1 and $47 for Part 2, plus 7%
+shipping/handling. The standard is divided into two parts, Part 1 being the
+actual specification, while Part 2 covers compliance testing methods. Part 1
+is titled "Digital Compression and Coding of Continuous-tone Still Images,
+Part 1: Requirements and guidelines" and has document numbers ISO/IEC IS
+10918-1, ITU-T T.81. Part 2 is titled "Digital Compression and Coding of
+Continuous-tone Still Images, Part 2: Compliance testing" and has document
+numbers ISO/IEC IS 10918-2, ITU-T T.83.
+
+Some extensions to the original JPEG standard are defined in JPEG Part 3,
+a newer ISO standard numbered ISO/IEC IS 10918-3 and ITU-T T.84. IJG
+currently does not support any Part 3 extensions.
+
+The JPEG standard does not specify all details of an interchangeable file
+format. For the omitted details we follow the "JFIF" conventions, revision
+1.02. A copy of the JFIF spec is available from:
+ Literature Department
+ C-Cube Microsystems, Inc.
+ 1778 McCarthy Blvd.
+ Milpitas, CA 95035
+ phone (408) 944-6300, fax (408) 944-6314
+A PostScript version of this document is available by FTP at
+ftp://ftp.uu.net/graphics/jpeg/jfif.ps.gz. There is also a plain text
+version at ftp://ftp.uu.net/graphics/jpeg/jfif.txt.gz, but it is missing
+the figures.
+
+The TIFF 6.0 file format specification can be obtained by FTP from
+ftp://ftp.sgi.com/graphics/tiff/TIFF6.ps.gz. The JPEG incorporation scheme
+found in the TIFF 6.0 spec of 3-June-92 has a number of serious problems.
+IJG does not recommend use of the TIFF 6.0 design (TIFF Compression tag 6).
+Instead, we recommend the JPEG design proposed by TIFF Technical Note #2
+(Compression tag 7). Copies of this Note can be obtained from ftp.sgi.com or
+from ftp://ftp.uu.net/graphics/jpeg/. It is expected that the next revision
+of the TIFF spec will replace the 6.0 JPEG design with the Note's design.
+Although IJG's own code does not support TIFF/JPEG, the free libtiff library
+uses our library to implement TIFF/JPEG per the Note. libtiff is available
+from ftp://ftp.sgi.com/graphics/tiff/.
+
+
+ARCHIVE LOCATIONS
+=================
+
+The "official" archive site for this software is ftp.uu.net (Internet
+address 192.48.96.9). The most recent released version can always be found
+there in directory graphics/jpeg. This particular version will be archived
+as ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz. If you don't have
+direct Internet access, UUNET's archives are also available via UUCP; contact
+help@uunet.uu.net for information on retrieving files that way.
+
+Numerous Internet sites maintain copies of the UUNET files. However, only
+ftp.uu.net is guaranteed to have the latest official version.
+
+You can also obtain this software in DOS-compatible "zip" archive format from
+the SimTel archives (ftp://ftp.simtel.net/pub/simtelnet/msdos/graphics/), or
+on CompuServe in the Graphics Support forum (GO CIS:GRAPHSUP), library 12
+"JPEG Tools". Again, these versions may sometimes lag behind the ftp.uu.net
+release.
+
+The JPEG FAQ (Frequently Asked Questions) article is a useful source of
+general information about JPEG. It is updated constantly and therefore is
+not included in this distribution. The FAQ is posted every two weeks to
+Usenet newsgroups comp.graphics.misc, news.answers, and other groups.
+It is available on the World Wide Web at http://www.faqs.org/faqs/jpeg-faq/
+and other news.answers archive sites, including the official news.answers
+archive at rtfm.mit.edu: ftp://rtfm.mit.edu/pub/usenet/news.answers/jpeg-faq/.
+If you don't have Web or FTP access, send e-mail to mail-server@rtfm.mit.edu
+with body
+ send usenet/news.answers/jpeg-faq/part1
+ send usenet/news.answers/jpeg-faq/part2
+
+
+RELATED SOFTWARE
+================
+
+Numerous viewing and image manipulation programs now support JPEG. (Quite a
+few of them use this library to do so.) The JPEG FAQ described above lists
+some of the more popular free and shareware viewers, and tells where to
+obtain them on Internet.
+
+If you are on a Unix machine, we highly recommend Jef Poskanzer's free
+PBMPLUS software, which provides many useful operations on PPM-format image
+files. In particular, it can convert PPM images to and from a wide range of
+other formats, thus making cjpeg/djpeg considerably more useful. The latest
+version is distributed by the NetPBM group, and is available from numerous
+sites, notably ftp://wuarchive.wustl.edu/graphics/graphics/packages/NetPBM/.
+Unfortunately PBMPLUS/NETPBM is not nearly as portable as the IJG software is;
+you are likely to have difficulty making it work on any non-Unix machine.
+
+A different free JPEG implementation, written by the PVRG group at Stanford,
+is available from ftp://havefun.stanford.edu/pub/jpeg/. This program
+is designed for research and experimentation rather than production use;
+it is slower, harder to use, and less portable than the IJG code, but it
+is easier to read and modify. Also, the PVRG code supports lossless JPEG,
+which we do not. (On the other hand, it doesn't do progressive JPEG.)
+
+
+FILE FORMAT WARS
+================
+
+Some JPEG programs produce files that are not compatible with our library.
+The root of the problem is that the ISO JPEG committee failed to specify a
+concrete file format. Some vendors "filled in the blanks" on their own,
+creating proprietary formats that no one else could read. (For example, none
+of the early commercial JPEG implementations for the Macintosh were able to
+exchange compressed files.)
+
+The file format we have adopted is called JFIF (see REFERENCES). This format
+has been agreed to by a number of major commercial JPEG vendors, and it has
+become the de facto standard. JFIF is a minimal or "low end" representation.
+We recommend the use of TIFF/JPEG (TIFF revision 6.0 as modified by TIFF
+Technical Note #2) for "high end" applications that need to record a lot of
+additional data about an image. TIFF/JPEG is fairly new and not yet widely
+supported, unfortunately.
+
+The upcoming JPEG Part 3 standard defines a file format called SPIFF.
+SPIFF is interoperable with JFIF, in the sense that most JFIF decoders should
+be able to read the most common variant of SPIFF. SPIFF has some technical
+advantages over JFIF, but its major claim to fame is simply that it is an
+official standard rather than an informal one. At this point it is unclear
+whether SPIFF will supersede JFIF or whether JFIF will remain the de-facto
+standard. IJG intends to support SPIFF once the standard is frozen, but we
+have not decided whether it should become our default output format or not.
+(In any case, our decoder will remain capable of reading JFIF indefinitely.)
+
+Various proprietary file formats incorporating JPEG compression also exist.
+We have little or no sympathy for the existence of these formats. Indeed,
+one of the original reasons for developing this free software was to help
+force convergence on common, open format standards for JPEG files. Don't
+use a proprietary file format!
+
+
+TO DO
+=====
+
+The major thrust for v7 will probably be improvement of visual quality.
+The current method for scaling the quantization tables is known not to be
+very good at low Q values. We also intend to investigate block boundary
+smoothing, "poor man's variable quantization", and other means of improving
+quality-vs-file-size performance without sacrificing compatibility.
+
+In future versions, we are considering supporting some of the upcoming JPEG
+Part 3 extensions --- principally, variable quantization and the SPIFF file
+format.
+
+As always, speeding things up is of great interest.
+
+Please send bug reports, offers of help, etc. to jpeg-info@uunet.uu.net.
--- /dev/null
+This directory contains a subset of the Independent JPEG Group's (IJG)
+libjpeg version 6b. We only include enough of distribution to build
+libjpeg. We do not include the standard executables that come with
+libjpeg (cjpeg, djpeg, etc.). Furthermore, the standard libjpeg build
+process is replaced with a CMake build process.
+
+We'd like to thank the IJG for distributing a public JPEG IO library.
+
+We'd like to also thank the dcmtk crew for releasing their toolkit under such a nice license that allow us to patch ijg properly to handle all sort of jpeg compression found in the DICOM implementation. The copyright can be found in COPYRIGHT.dcmtk.
+
+Modifications
+-------------
+
+1.
+jconfig.h is usually generated by the build process. For this distribution,
+we ship a version of jconfig.h.in to be used across several platforms. It's
+purpose is also to allow generation of both 8bits and 12bits lib.
+
+
+
+2.
+jdhuff.c was modified to support special Philips MRI image:
+
+Index: jdhuff.c
+===================================================================
+RCS file: /cvs/public/gdcm/src/jpeg/libijg8/jdhuff.c,v
+retrieving revision 1.1
+diff -u -3 -p -r1.1 jdhuff.c
+--- jdhuff.c 24 Jun 2003 10:09:48 -0000 1.1
++++ jdhuff.c 7 Oct 2004 02:29:43 -0000
+@@ -259,8 +259,11 @@ jpeg_make_d_derived_tbl (j_decompress_pt
+ if (isDC) {
+ for (i = 0; i < numsymbols; i++) {
+ int sym = htbl->huffval[i];
+- if (sym < 0 || sym > 15)
+- ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
++ if (sym < 0 || sym > 15) {
++ // Now, we can read Philips MRI Images
++ htbl->huffval[i]=15;
++// ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
++ }
+ }
+ }
+ }
+
+
+3.
+jmorecfg.h was modified so that we can modify it automatically at build time to
+either generate a 8bits jpeg lib or 12bits jpeg library:
+
+Index: jmorecfg.h
+===================================================================
+RCS file: /cvs/public/gdcm/src/jpeg/libijg8/jmorecfg.h,v
+retrieving revision 1.4
+diff -u -3 -p -r1.4 jmorecfg.h
+--- jmorecfg.h 31 Oct 2003 14:59:50 -0000 1.4
++++ jmorecfg.h 7 Oct 2004 02:30:40 -0000
+@@ -19,7 +19,8 @@
+ * We do not support run-time selection of data precision, sorry.
+ */
+
+-#define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
++//#define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
++#define BITS_IN_JSAMPLE @GDCM_BITS_IN_JSAMPLE@
+
+ /*
+ * Maximum number of components (color channels) allowed in JPEG image.
+
+
+
+
+4.
+To further allow us to have to different copy of the 8, 12 and 16 bits jpeg
+library we had to mangle the name. Fur this purpose two new file were added to
+the library: gdcm_mangle_8bits.h, gdcm_mangle_12bits.h and gdcm_mangle_16bits.h.
+Those file were generated using:
+
+ nm libgdcmijpeg8.a | grep " [R|T] " | colrm 1 11 | sort
+
+
+5.
+In order to read lossless images, we had to apply the ls-patch to jpeg-6b. So I started from scratch:
+
+tar xvfz /tmp/jpegsrc.v6b.tar.gz (1)
+patch < /tmp/ljpeg-6b.patch (2)
+patch -p0 < arithmetic-without-arith-option-full.patch (3)
+patch -p0 < warnings10-14.patch (4)
+patch -p0 < previous-gdcm.patch (5)
+-----------------------------------------------------------
+= The subdir src/jpeg/libijg
+
+(now I also need to apply the redhat patch for cplusplus lib)
+
+(1) http://www.ijg.org/files/jpegsrc.v6b.tar.gz
+(2) http://www.oceana.com/ftp/ljpeg/ljpeg-patch.v6b.tar.gz
+(3), (4) and (5) http://www.creatis.insa-lyon.fr/~malaterre/jpeg/
+
+(3) Was made with a carefull inspection of dcmtk code (see convert.sh at the same spot as the patch)
+(4) Is basically just compilation of the lib with -W -Wall -Werror
+(5) This contains some configuration copy/paste from VTK, and the 'well known' 12 bits Philips MRI DICOM patch
+
+
+
+NOTE for later:
+(shoud we disable getenv just as dcmtk ? there is a ijg flag for that NO_ENV or something similar
--- /dev/null
+CHANGE LOG for Independent JPEG Group's JPEG software
+
+
+Version 6b 27-Mar-1998
+-----------------------
+
+jpegtran has new features for lossless image transformations (rotation
+and flipping) as well as "lossless" reduction to grayscale.
+
+jpegtran now copies comments by default; it has a -copy switch to enable
+copying all APPn blocks as well, or to suppress comments. (Formerly it
+always suppressed comments and APPn blocks.) jpegtran now also preserves
+JFIF version and resolution information.
+
+New decompressor library feature: COM and APPn markers found in the input
+file can be saved in memory for later use by the application. (Before,
+you had to code this up yourself with a custom marker processor.)
+
+There is an unused field "void * client_data" now in compress and decompress
+parameter structs; this may be useful in some applications.
+
+JFIF version number information is now saved by the decoder and accepted by
+the encoder. jpegtran uses this to copy the source file's version number,
+to ensure "jpegtran -copy all" won't create bogus files that contain JFXX
+extensions but claim to be version 1.01. Applications that generate their
+own JFXX extension markers also (finally) have a supported way to cause the
+encoder to emit JFIF version number 1.02.
+
+djpeg's trace mode reports JFIF 1.02 thumbnail images as such, rather
+than as unknown APP0 markers.
+
+In -verbose mode, djpeg and rdjpgcom will try to print the contents of
+APP12 markers as text. Some digital cameras store useful text information
+in APP12 markers.
+
+Handling of truncated data streams is more robust: blocks beyond the one in
+which the error occurs will be output as uniform gray, or left unchanged
+if decoding a progressive JPEG. The appearance no longer depends on the
+Huffman tables being used.
+
+Huffman tables are checked for validity much more carefully than before.
+
+To avoid the Unisys LZW patent, djpeg's GIF output capability has been
+changed to produce "uncompressed GIFs", and cjpeg's GIF input capability
+has been removed altogether. We're not happy about it either, but there
+seems to be no good alternative.
+
+The configure script now supports building libjpeg as a shared library
+on many flavors of Unix (all the ones that GNU libtool knows how to
+build shared libraries for). Use "./configure --enable-shared" to
+try this out.
+
+New jconfig file and makefiles for Microsoft Visual C++ and Developer Studio.
+Also, a jconfig file and a build script for Metrowerks CodeWarrior
+on Apple Macintosh. makefile.dj has been updated for DJGPP v2, and there
+are miscellaneous other minor improvements in the makefiles.
+
+jmemmac.c now knows how to create temporary files following Mac System 7
+conventions.
+
+djpeg's -map switch is now able to read raw-format PPM files reliably.
+
+cjpeg -progressive -restart no longer generates any unnecessary DRI markers.
+
+Multiple calls to jpeg_simple_progression for a single JPEG object
+no longer leak memory.
+
+
+Version 6a 7-Feb-96
+--------------------
+
+Library initialization sequence modified to detect version mismatches
+and struct field packing mismatches between library and calling application.
+This change requires applications to be recompiled, but does not require
+any application source code change.
+
+All routine declarations changed to the style "GLOBAL(type) name ...",
+that is, GLOBAL, LOCAL, METHODDEF, EXTERN are now macros taking the
+routine's return type as an argument. This makes it possible to add
+Microsoft-style linkage keywords to all the routines by changing just
+these macros. Note that any application code that was using these macros
+will have to be changed.
+
+DCT coefficient quantization tables are now stored in normal array order
+rather than zigzag order. Application code that calls jpeg_add_quant_table,
+or otherwise manipulates quantization tables directly, will need to be
+changed. If you need to make such code work with either older or newer
+versions of the library, a test like "#if JPEG_LIB_VERSION >= 61" is
+recommended.
+
+djpeg's trace capability now dumps DQT tables in natural order, not zigzag
+order. This allows the trace output to be made into a "-qtables" file
+more easily.
+
+New system-dependent memory manager module for use on Apple Macintosh.
+
+Fix bug in cjpeg's -smooth option: last one or two scanlines would be
+duplicates of the prior line unless the image height mod 16 was 1 or 2.
+
+Repair minor problems in VMS, BCC, MC6 makefiles.
+
+New configure script based on latest GNU Autoconf.
+
+Correct the list of include files needed by MetroWerks C for ccommand().
+
+Numerous small documentation updates.
+
+
+Version 6 2-Aug-95
+-------------------
+
+Progressive JPEG support: library can read and write full progressive JPEG
+files. A "buffered image" mode supports incremental decoding for on-the-fly
+display of progressive images. Simply recompiling an existing IJG-v5-based
+decoder with v6 should allow it to read progressive files, though of course
+without any special progressive display.
+
+New "jpegtran" application performs lossless transcoding between different
+JPEG formats; primarily, it can be used to convert baseline to progressive
+JPEG and vice versa. In support of jpegtran, the library now allows lossless
+reading and writing of JPEG files as DCT coefficient arrays. This ability
+may be of use in other applications.
+
+Notes for programmers:
+* We changed jpeg_start_decompress() to be able to suspend; this makes all
+decoding modes available to suspending-input applications. However,
+existing applications that use suspending input will need to be changed
+to check the return value from jpeg_start_decompress(). You don't need to
+do anything if you don't use a suspending data source.
+* We changed the interface to the virtual array routines: access_virt_array
+routines now take a count of the number of rows to access this time. The
+last parameter to request_virt_array routines is now interpreted as the
+maximum number of rows that may be accessed at once, but not necessarily
+the height of every access.
+
+
+Version 5b 15-Mar-95
+---------------------
+
+Correct bugs with grayscale images having v_samp_factor > 1.
+
+jpeg_write_raw_data() now supports output suspension.
+
+Correct bugs in "configure" script for case of compiling in
+a directory other than the one containing the source files.
+
+Repair bug in jquant1.c: sometimes didn't use as many colors as it could.
+
+Borland C makefile and jconfig file work under either MS-DOS or OS/2.
+
+Miscellaneous improvements to documentation.
+
+
+Version 5a 7-Dec-94
+--------------------
+
+Changed color conversion roundoff behavior so that grayscale values are
+represented exactly. (This causes test image files to change.)
+
+Make ordered dither use 16x16 instead of 4x4 pattern for a small quality
+improvement.
+
+New configure script based on latest GNU Autoconf.
+Fix configure script to handle CFLAGS correctly.
+Rename *.auto files to *.cfg, so that configure script still works if
+file names have been truncated for DOS.
+
+Fix bug in rdbmp.c: didn't allow for extra data between header and image.
+
+Modify rdppm.c/wrppm.c to handle 2-byte raw PPM/PGM formats for 12-bit data.
+
+Fix several bugs in rdrle.c.
+
+NEED_SHORT_EXTERNAL_NAMES option was broken.
+
+Revise jerror.h/jerror.c for more flexibility in message table.
+
+Repair oversight in jmemname.c NO_MKTEMP case: file could be there
+but unreadable.
+
+
+Version 5 24-Sep-94
+--------------------
+
+Version 5 represents a nearly complete redesign and rewrite of the IJG
+software. Major user-visible changes include:
+ * Automatic configuration simplifies installation for most Unix systems.
+ * A range of speed vs. image quality tradeoffs are supported.
+ This includes resizing of an image during decompression: scaling down
+ by a factor of 1/2, 1/4, or 1/8 is handled very efficiently.
+ * New programs rdjpgcom and wrjpgcom allow insertion and extraction
+ of text comments in a JPEG file.
+
+The application programmer's interface to the library has changed completely.
+Notable improvements include:
+ * We have eliminated the use of callback routines for handling the
+ uncompressed image data. The application now sees the library as a
+ set of routines that it calls to read or write image data on a
+ scanline-by-scanline basis.
+ * The application image data is represented in a conventional interleaved-
+ pixel format, rather than as a separate array for each color channel.
+ This can save a copying step in many programs.
+ * The handling of compressed data has been cleaned up: the application can
+ supply routines to source or sink the compressed data. It is possible to
+ suspend processing on source/sink buffer overrun, although this is not
+ supported in all operating modes.
+ * All static state has been eliminated from the library, so that multiple
+ instances of compression or decompression can be active concurrently.
+ * JPEG abbreviated datastream formats are supported, ie, quantization and
+ Huffman tables can be stored separately from the image data.
+ * And not only that, but the documentation of the library has improved
+ considerably!
+
+
+The last widely used release before the version 5 rewrite was version 4A of
+18-Feb-93. Change logs before that point have been discarded, since they
+are not of much interest after the rewrite.
--- /dev/null
+IJG JPEG LIBRARY: FILE LIST
+
+Copyright (C) 1994-1997, Thomas G. Lane.
+This file is part of the Independent JPEG Group's software.
+For conditions of distribution and use, see the accompanying README file.
+
+
+Here is a road map to the files in the IJG JPEG distribution. The
+distribution includes the JPEG library proper, plus two application
+programs ("cjpeg" and "djpeg") which use the library to convert JPEG
+files to and from some other popular image formats. A third application
+"jpegtran" uses the library to do lossless conversion between different
+variants of JPEG. There are also two stand-alone applications,
+"rdjpgcom" and "wrjpgcom".
+
+
+THE JPEG LIBRARY
+================
+
+Include files:
+
+jpeglib.h JPEG library's exported data and function declarations.
+jconfig.h Configuration declarations. Note: this file is not present
+ in the distribution; it is generated during installation.
+jmorecfg.h Additional configuration declarations; need not be changed
+ for a standard installation.
+jerror.h Declares JPEG library's error and trace message codes.
+jinclude.h Central include file used by all IJG .c files to reference
+ system include files.
+jpegint.h JPEG library's internal data structures.
+jlossls.h JPEG library's lossless codec data structures.
+jlossy.h JPEG library's lossy codec structures.
+jchuff.h Private declarations for Huffman encoder modules.
+jdhuff.h Private declarations for Huffman decoder modules.
+jdct.h Private declarations for forward & reverse DCT subsystems.
+jmemsys.h Private declarations for memory management subsystem.
+jversion.h Version information.
+
+Applications using the library should include jpeglib.h (which in turn
+includes jconfig.h and jmorecfg.h). Optionally, jerror.h may be included
+if the application needs to reference individual JPEG error codes. The
+other include files are intended for internal use and would not normally
+be included by an application program. (cjpeg/djpeg/etc do use jinclude.h,
+since its function is to improve portability of the whole IJG distribution.
+Most other applications will directly include the system include files they
+want, and hence won't need jinclude.h.)
+
+
+C source code files:
+
+These files contain most of the functions intended to be called directly by
+an application program:
+
+jcapimin.c Application program interface: core routines for compression.
+jcapistd.c Application program interface: standard compression.
+jdapimin.c Application program interface: core routines for decompression.
+jdapistd.c Application program interface: standard decompression.
+jcomapi.c Application program interface routines common to compression
+ and decompression.
+jcparam.c Compression parameter setting helper routines.
+jctrans.c API and library routines for transcoding compression.
+jdtrans.c API and library routines for transcoding decompression.
+
+Compression side of the library:
+
+jcinit.c Initialization: determines which other modules to use.
+jcmaster.c Master control: setup and inter-pass sequencing logic.
+jcmainct.c Main buffer controller (preprocessor => JPEG compressor).
+jchuff.c Codec-independent Huffman entropy encoding routines.
+jcprepct.c Preprocessor buffer controller.
+jccolor.c Color space conversion.
+jcsample.c Downsampling.
+jcmarker.c JPEG marker writing.
+jdatadst.c Data destination manager for stdio output.
+
+Lossy (DCT) codec:
+
+jlossy.c Lossy compressor proper.
+jccoefct.c Buffer controller for DCT coefficient buffer.
+jcdctmgr.c DCT manager (DCT implementation selection & control).
+jfdctint.c Forward DCT using slow-but-accurate integer method.
+jfdctfst.c Forward DCT using faster, less accurate integer method.
+jfdctflt.c Forward DCT using floating-point arithmetic.
+jcshuff.c Huffman entropy coding for sequential JPEG.
+jcphuff.c Huffman entropy coding for progressive JPEG.
+
+Lossless (spatial) codec:
+
+jclossls.c Lossless compressor proper.
+jcdiffct.c Buffer controller for difference buffer.
+jcscale.c Point transformation.
+jcpred.c Sample predictor and differencer.
+jclhuff.c Huffman entropy encoding for lossless JPEG.
+
+Decompression side of the library:
+
+jdmaster.c Master control: determines which other modules to use.
+jdinput.c Input controller: controls input processing modules.
+jdmainct.c Main buffer controller (JPEG decompressor => postprocessor).
+jdhuff.c Codec-independent Huffman entropy decoding routines.
+jdpostct.c Postprocessor buffer controller.
+jdmarker.c JPEG marker reading.
+jdsample.c Upsampling.
+jdcolor.c Color space conversion.
+jdmerge.c Merged upsampling/color conversion (faster, lower quality).
+jquant1.c One-pass color quantization using a fixed-spacing colormap.
+jquant2.c Two-pass color quantization using a custom-generated colormap.
+ Also handles one-pass quantization to an externally given map.
+jdatasrc.c Data source manager for stdio input.
+
+Lossy (DCT) codec:
+
+jdlossy.c Lossy decompressor proper.
+jdcoefct.c Buffer controller for DCT coefficient buffer.
+jdshuff.c Huffman entropy decoding for sequential JPEG.
+jdphuff.c Huffman entropy decoding for progressive JPEG.
+jddctmgr.c IDCT manager (IDCT implementation selection & control).
+jidctint.c Inverse DCT using slow-but-accurate integer method.
+jidctfst.c Inverse DCT using faster, less accurate integer method.
+jidctflt.c Inverse DCT using floating-point arithmetic.
+jidctred.c Inverse DCTs with reduced-size outputs.
+
+Lossless (spatial) codec:
+
+jdlossls.c Lossless decompressor proper.
+jddiffct.c Buffer controller for difference buffers.
+jdlhuff.c Huffman entropy decoding for lossless JPEG.
+jdpred.c Sample predictor and undifferencer.
+jdscale.c Point transformation, sample size scaling.
+
+Support files for both compression and decompression:
+
+jerror.c Standard error handling routines (application replaceable).
+jmemmgr.c System-independent (more or less) memory management code.
+jcodec.c Codec-independent utility routines.
+jutils.c Miscellaneous utility routines.
+
+jmemmgr.c relies on a system-dependent memory management module. The IJG
+distribution includes the following implementations of the system-dependent
+module:
+
+jmemnobs.c "No backing store": assumes adequate virtual memory exists.
+jmemansi.c Makes temporary files with ANSI-standard routine tmpfile().
+jmemname.c Makes temporary files with program-generated file names.
+jmemdos.c Custom implementation for MS-DOS (16-bit environment only):
+ can use extended and expanded memory as well as temp files.
+jmemmac.c Custom implementation for Apple Macintosh.
+
+Exactly one of the system-dependent modules should be configured into an
+installed JPEG library (see install.doc for hints about which one to use).
+On unusual systems you may find it worthwhile to make a special
+system-dependent memory manager.
+
+
+Non-C source code files:
+
+jmemdosa.asm 80x86 assembly code support for jmemdos.c; used only in
+ MS-DOS-specific configurations of the JPEG library.
+
+
+CJPEG/DJPEG/JPEGTRAN
+====================
+
+Include files:
+
+cdjpeg.h Declarations shared by cjpeg/djpeg/jpegtran modules.
+cderror.h Additional error and trace message codes for cjpeg et al.
+transupp.h Declarations for jpegtran support routines in transupp.c.
+
+C source code files:
+
+cjpeg.c Main program for cjpeg.
+djpeg.c Main program for djpeg.
+jpegtran.c Main program for jpegtran.
+cdjpeg.c Utility routines used by all three programs.
+rdcolmap.c Code to read a colormap file for djpeg's "-map" switch.
+rdswitch.c Code to process some of cjpeg's more complex switches.
+ Also used by jpegtran.
+transupp.c Support code for jpegtran: lossless image manipulations.
+
+Image file reader modules for cjpeg:
+
+rdbmp.c BMP file input.
+rdgif.c GIF file input (now just a stub).
+rdppm.c PPM/PGM file input.
+rdrle.c Utah RLE file input.
+rdtarga.c Targa file input.
+
+Image file writer modules for djpeg:
+
+wrbmp.c BMP file output.
+wrgif.c GIF file output (a mere shadow of its former self).
+wrppm.c PPM/PGM file output.
+wrrle.c Utah RLE file output.
+wrtarga.c Targa file output.
+
+
+RDJPGCOM/WRJPGCOM
+=================
+
+C source code files:
+
+rdjpgcom.c Stand-alone rdjpgcom application.
+wrjpgcom.c Stand-alone wrjpgcom application.
+
+These programs do not depend on the IJG library. They do use
+jconfig.h and jinclude.h, only to improve portability.
+
+
+ADDITIONAL FILES
+================
+
+Documentation (see README for a guide to the documentation files):
+
+README Master documentation file.
+*.doc Other documentation files.
+*.1 Documentation in Unix man page format.
+change.log Version-to-version change highlights.
+example.c Sample code for calling JPEG library.
+
+Configuration/installation files and programs (see install.doc for more info):
+
+configure Unix shell script to perform automatic configuration.
+ltconfig Support scripts for configure (from GNU libtool).
+ltmain.sh
+config.guess
+config.sub
+install-sh Install shell script for those Unix systems lacking one.
+ckconfig.c Program to generate jconfig.h on non-Unix systems.
+jconfig.doc Template for making jconfig.h by hand.
+makefile.* Sample makefiles for particular systems.
+jconfig.* Sample jconfig.h for particular systems.
+ansi2knr.c De-ANSIfier for pre-ANSI C compilers (courtesy of
+ L. Peter Deutsch and Aladdin Enterprises).
+
+Test files (see install.doc for test procedure):
+
+test*.* Source and comparison files for confidence test.
+ These are binary image files, NOT text files.
--- /dev/null
+INSTALLATION INSTRUCTIONS for the Independent JPEG Group's JPEG software
+
+Copyright (C) 1991-1998, Thomas G. Lane.
+This file is part of the Independent JPEG Group's software.
+For conditions of distribution and use, see the accompanying README file.
+
+
+This file explains how to configure and install the IJG software. We have
+tried to make this software extremely portable and flexible, so that it can be
+adapted to almost any environment. The downside of this decision is that the
+installation process is complicated. We have provided shortcuts to simplify
+the task on common systems. But in any case, you will need at least a little
+familiarity with C programming and program build procedures for your system.
+
+If you are only using this software as part of a larger program, the larger
+program's installation procedure may take care of configuring the IJG code.
+For example, Ghostscript's installation script will configure the IJG code.
+You don't need to read this file if you just want to compile Ghostscript.
+
+If you are on a Unix machine, you may not need to read this file at all.
+Try doing
+ ./configure
+ make
+ make test
+If that doesn't complain, do
+ make install
+(better do "make -n install" first to see if the makefile will put the files
+where you want them). Read further if you run into snags or want to customize
+the code for your system.
+
+
+TABLE OF CONTENTS
+-----------------
+
+Before you start
+Configuring the software:
+ using the automatic "configure" script
+ using one of the supplied jconfig and makefile files
+ by hand
+Building the software
+Testing the software
+Installing the software
+Optional stuff
+Optimization
+Hints for specific systems
+
+
+BEFORE YOU START
+================
+
+Before installing the software you must unpack the distributed source code.
+Since you are reading this file, you have probably already succeeded in this
+task. However, there is a potential for error if you needed to convert the
+files to the local standard text file format (for example, if you are on
+MS-DOS you may have converted LF end-of-line to CR/LF). You must apply
+such conversion to all the files EXCEPT those whose names begin with "test".
+The test files contain binary data; if you change them in any way then the
+self-test will give bad results.
+
+Please check the last section of this file to see if there are hints for the
+specific machine or compiler you are using.
+
+
+CONFIGURING THE SOFTWARE
+========================
+
+To configure the IJG code for your system, you need to create two files:
+ * jconfig.h: contains values for system-dependent #define symbols.
+ * Makefile: controls the compilation process.
+(On a non-Unix machine, you may create "project files" or some other
+substitute for a Makefile. jconfig.h is needed in any environment.)
+
+We provide three different ways to generate these files:
+ * On a Unix system, you can just run the "configure" script.
+ * We provide sample jconfig files and makefiles for popular machines;
+ if your machine matches one of the samples, just copy the right sample
+ files to jconfig.h and Makefile.
+ * If all else fails, read the instructions below and make your own files.
+
+
+Configuring the software using the automatic "configure" script
+---------------------------------------------------------------
+
+If you are on a Unix machine, you can just type
+ ./configure
+and let the configure script construct appropriate configuration files.
+If you're using "csh" on an old version of System V, you might need to type
+ sh configure
+instead to prevent csh from trying to execute configure itself.
+Expect configure to run for a few minutes, particularly on slower machines;
+it works by compiling a series of test programs.
+
+Configure was created with GNU Autoconf and it follows the usual conventions
+for GNU configure scripts. It makes a few assumptions that you may want to
+override. You can do this by providing optional switches to configure:
+
+* If you want to build libjpeg as a shared library, say
+ ./configure --enable-shared
+To get both shared and static libraries, say
+ ./configure --enable-shared --enable-static
+Note that these switches invoke GNU libtool to take care of system-dependent
+shared library building methods. If things don't work this way, please try
+running configure without either switch; that should build a static library
+without using libtool. If that works, your problem is probably with libtool
+not with the IJG code. libtool is fairly new and doesn't support all flavors
+of Unix yet. (You might be able to find a newer version of libtool than the
+one included with libjpeg; see ftp.gnu.org. Report libtool problems to
+bug-libtool@gnu.org.)
+
+* Configure will use gcc (GNU C compiler) if it's available, otherwise cc.
+To force a particular compiler to be selected, use the CC option, for example
+ ./configure CC='cc'
+The same method can be used to include any unusual compiler switches.
+For example, on HP-UX you probably want to say
+ ./configure CC='cc -Aa'
+to get HP's compiler to run in ANSI mode.
+
+* The default CFLAGS setting is "-O" for non-gcc compilers, "-O2" for gcc.
+You can override this by saying, for example,
+ ./configure CFLAGS='-g'
+if you want to compile with debugging support.
+
+* Configure will set up the makefile so that "make install" will install files
+into /usr/local/bin, /usr/local/man, etc. You can specify an installation
+prefix other than "/usr/local" by giving configure the option "--prefix=PATH".
+
+* If you don't have a lot of swap space, you may need to enable the IJG
+software's internal virtual memory mechanism. To do this, give the option
+"--enable-maxmem=N" where N is the default maxmemory limit in megabytes.
+This is discussed in more detail under "Selecting a memory manager", below.
+You probably don't need to worry about this on reasonably-sized Unix machines,
+unless you plan to process very large images.
+
+Configure has some other features that are useful if you are cross-compiling
+or working in a network of multiple machine types; but if you need those
+features, you probably already know how to use them.
+
+
+Configuring the software using one of the supplied jconfig and makefile files
+-----------------------------------------------------------------------------
+
+If you have one of these systems, you can just use the provided configuration
+files:
+
+Makefile jconfig file System and/or compiler
+
+makefile.manx jconfig.manx Amiga, Manx Aztec C
+makefile.sas jconfig.sas Amiga, SAS C
+makeproj.mac jconfig.mac Apple Macintosh, Metrowerks CodeWarrior
+mak*jpeg.st jconfig.st Atari ST/STE/TT, Pure C or Turbo C
+makefile.bcc jconfig.bcc MS-DOS or OS/2, Borland C
+makefile.dj jconfig.dj MS-DOS, DJGPP (Delorie's port of GNU C)
+makefile.mc6 jconfig.mc6 MS-DOS, Microsoft C (16-bit only)
+makefile.wat jconfig.wat MS-DOS, OS/2, or Windows NT, Watcom C
+makefile.vc jconfig.vc Windows NT/95, MS Visual C++
+make*.ds jconfig.vc Windows NT/95, MS Developer Studio
+makefile.mms jconfig.vms Digital VMS, with MMS software
+makefile.vms jconfig.vms Digital VMS, without MMS software
+
+Copy the proper jconfig file to jconfig.h and the makefile to Makefile (or
+whatever your system uses as the standard makefile name). For more info see
+the appropriate system-specific hints section near the end of this file.
+
+
+Configuring the software by hand
+--------------------------------
+
+First, generate a jconfig.h file. If you are moderately familiar with C,
+the comments in jconfig.doc should be enough information to do this; just
+copy jconfig.doc to jconfig.h and edit it appropriately. Otherwise, you may
+prefer to use the ckconfig.c program. You will need to compile and execute
+ckconfig.c by hand --- we hope you know at least enough to do that.
+ckconfig.c may not compile the first try (in fact, the whole idea is for it
+to fail if anything is going to). If you get compile errors, fix them by
+editing ckconfig.c according to the directions given in ckconfig.c. Once
+you get it to run, it will write a suitable jconfig.h file, and will also
+print out some advice about which makefile to use.
+
+You may also want to look at the canned jconfig files, if there is one for a
+system similar to yours.
+
+Second, select a makefile and copy it to Makefile (or whatever your system
+uses as the standard makefile name). The most generic makefiles we provide
+are
+ makefile.ansi: if your C compiler supports function prototypes
+ makefile.unix: if not.
+(You have function prototypes if ckconfig.c put "#define HAVE_PROTOTYPES"
+in jconfig.h.) You may want to start from one of the other makefiles if
+there is one for a system similar to yours.
+
+Look over the selected Makefile and adjust options as needed. In particular
+you may want to change the CC and CFLAGS definitions. For instance, if you
+are using GCC, set CC=gcc. If you had to use any compiler switches to get
+ckconfig.c to work, make sure the same switches are in CFLAGS.
+
+If you are on a system that doesn't use makefiles, you'll need to set up
+project files (or whatever you do use) to compile all the source files and
+link them into executable files cjpeg, djpeg, jpegtran, rdjpgcom, and wrjpgcom.
+See the file lists in any of the makefiles to find out which files go into
+each program. Note that the provided makefiles all make a "library" file
+libjpeg first, but you don't have to do that if you don't want to; the file
+lists identify which source files are actually needed for compression,
+decompression, or both. As a last resort, you can make a batch script that
+just compiles everything and links it all together; makefile.vms is an example
+of this (it's for VMS systems that have no make-like utility).
+
+Here are comments about some specific configuration decisions you'll
+need to make:
+
+Command line style
+------------------
+
+These programs can use a Unix-like command line style which supports
+redirection and piping, like this:
+ cjpeg inputfile >outputfile
+ cjpeg <inputfile >outputfile
+ source program | cjpeg >outputfile
+The simpler "two file" command line style is just
+ cjpeg inputfile outputfile
+You may prefer the two-file style, particularly if you don't have pipes.
+
+You MUST use two-file style on any system that doesn't cope well with binary
+data fed through stdin/stdout; this is true for some MS-DOS compilers, for
+example. If you're not on a Unix system, it's safest to assume you need
+two-file style. (But if your compiler provides either the Posix-standard
+fdopen() library routine or a Microsoft-compatible setmode() routine, you
+can safely use the Unix command line style, by defining USE_FDOPEN or
+USE_SETMODE respectively.)
+
+To use the two-file style, make jconfig.h say "#define TWO_FILE_COMMANDLINE".
+
+Selecting a memory manager
+--------------------------
+
+The IJG code is capable of working on images that are too big to fit in main
+memory; data is swapped out to temporary files as necessary. However, the
+code to do this is rather system-dependent. We provide five different
+memory managers:
+
+* jmemansi.c This version uses the ANSI-standard library routine tmpfile(),
+ which not all non-ANSI systems have. On some systems
+ tmpfile() may put the temporary file in a non-optimal
+ location; if you don't like what it does, use jmemname.c.
+
+* jmemname.c This version creates named temporary files. For anything
+ except a Unix machine, you'll need to configure the
+ select_file_name() routine appropriately; see the comments
+ near the head of jmemname.c. If you use this version, define
+ NEED_SIGNAL_CATCHER in jconfig.h to make sure the temp files
+ are removed if the program is aborted.
+
+* jmemnobs.c (That stands for No Backing Store :-).) This will compile on
+ almost any system, but it assumes you have enough main memory
+ or virtual memory to hold the biggest images you work with.
+
+* jmemdos.c This should be used with most 16-bit MS-DOS compilers.
+ See the system-specific notes about MS-DOS for more info.
+ IMPORTANT: if you use this, define USE_MSDOS_MEMMGR in
+ jconfig.h, and include the assembly file jmemdosa.asm in the
+ programs. The supplied makefiles and jconfig files for
+ 16-bit MS-DOS compilers already do both.
+
+* jmemmac.c Custom version for Apple Macintosh; see the system-specific
+ notes for Macintosh for more info.
+
+To use a particular memory manager, change the SYSDEPMEM variable in your
+makefile to equal the corresponding object file name (for example, jmemansi.o
+or jmemansi.obj for jmemansi.c).
+
+If you have plenty of (real or virtual) main memory, just use jmemnobs.c.
+"Plenty" means about ten bytes for every pixel in the largest images
+you plan to process, so a lot of systems don't meet this criterion.
+If yours doesn't, try jmemansi.c first. If that doesn't compile, you'll have
+to use jmemname.c; be sure to adjust select_file_name() for local conditions.
+You may also need to change unlink() to remove() in close_backing_store().
+
+Except with jmemnobs.c or jmemmac.c, you need to adjust the DEFAULT_MAX_MEM
+setting to a reasonable value for your system (either by adding a #define for
+DEFAULT_MAX_MEM to jconfig.h, or by adding a -D switch to the Makefile).
+This value limits the amount of data space the program will attempt to
+allocate. Code and static data space isn't counted, so the actual memory
+needs for cjpeg or djpeg are typically 100 to 150Kb more than the max-memory
+setting. Larger max-memory settings reduce the amount of I/O needed to
+process a large image, but too large a value can result in "insufficient
+memory" failures. On most Unix machines (and other systems with virtual
+memory), just set DEFAULT_MAX_MEM to several million and forget it. At the
+other end of the spectrum, for MS-DOS machines you probably can't go much
+above 300K to 400K. (On MS-DOS the value refers to conventional memory only.
+Extended/expanded memory is handled separately by jmemdos.c.)
+
+
+BUILDING THE SOFTWARE
+=====================
+
+Now you should be able to compile the software. Just say "make" (or
+whatever's necessary to start the compilation). Have a cup of coffee.
+
+Here are some things that could go wrong:
+
+If your compiler complains about undefined structures, you should be able to
+shut it up by putting "#define INCOMPLETE_TYPES_BROKEN" in jconfig.h.
+
+If you have trouble with missing system include files or inclusion of the
+wrong ones, read jinclude.h. This shouldn't happen if you used configure
+or ckconfig.c to set up jconfig.h.
+
+There are a fair number of routines that do not use all of their parameters;
+some compilers will issue warnings about this, which you can ignore. There
+are also a few configuration checks that may give "unreachable code" warnings.
+Any other warning deserves investigation.
+
+If you don't have a getenv() library routine, define NO_GETENV.
+
+Also see the system-specific hints, below.
+
+
+TESTING THE SOFTWARE
+====================
+
+As a quick test of functionality we've included a small sample image in
+several forms:
+ testorig.jpg Starting point for the djpeg tests.
+ testimg.ppm The output of djpeg testorig.jpg
+ testimg.bmp The output of djpeg -bmp -colors 256 testorig.jpg
+ testimg.jpg The output of cjpeg testimg.ppm
+ testprog.jpg Progressive-mode equivalent of testorig.jpg.
+ testimgp.jpg The output of cjpeg -progressive -optimize testimg.ppm
+(The first- and second-generation .jpg files aren't identical since JPEG is
+lossy.) If you can generate duplicates of the testimg* files then you
+probably have working programs.
+
+With most of the makefiles, "make test" will perform the necessary
+comparisons.
+
+If you're using a makefile that doesn't provide the test option, run djpeg
+and cjpeg by hand and compare the output files to testimg* with whatever
+binary file comparison tool you have. The files should be bit-for-bit
+identical.
+
+If the programs complain "MAX_ALLOC_CHUNK is wrong, please fix", then you
+need to reduce MAX_ALLOC_CHUNK to a value that fits in type size_t.
+Try adding "#define MAX_ALLOC_CHUNK 65520L" to jconfig.h. A less likely
+configuration error is "ALIGN_TYPE is wrong, please fix": defining ALIGN_TYPE
+as long should take care of that one.
+
+If the cjpeg test run fails with "Missing Huffman code table entry", it's a
+good bet that you needed to define RIGHT_SHIFT_IS_UNSIGNED. Go back to the
+configuration step and run ckconfig.c. (This is a good plan for any other
+test failure, too.)
+
+If you are using Unix (one-file) command line style on a non-Unix system,
+it's a good idea to check that binary I/O through stdin/stdout actually
+works. You should get the same results from "djpeg <testorig.jpg >out.ppm"
+as from "djpeg -outfile out.ppm testorig.jpg". Note that the makefiles all
+use the latter style and therefore do not exercise stdin/stdout! If this
+check fails, try recompiling with USE_SETMODE or USE_FDOPEN defined.
+If it still doesn't work, better use two-file style.
+
+If you chose a memory manager other than jmemnobs.c, you should test that
+temporary-file usage works. Try "djpeg -bmp -colors 256 -max 0 testorig.jpg"
+and make sure its output matches testimg.bmp. If you have any really large
+images handy, try compressing them with -optimize and/or decompressing with
+-colors 256 to make sure your DEFAULT_MAX_MEM setting is not too large.
+
+NOTE: this is far from an exhaustive test of the JPEG software; some modules,
+such as 1-pass color quantization, are not exercised at all. It's just a
+quick test to give you some confidence that you haven't missed something
+major.
+
+
+INSTALLING THE SOFTWARE
+=======================
+
+Once you're done with the above steps, you can install the software by
+copying the executable files (cjpeg, djpeg, jpegtran, rdjpgcom, and wrjpgcom)
+to wherever you normally install programs. On Unix systems, you'll also want
+to put the man pages (cjpeg.1, djpeg.1, jpegtran.1, rdjpgcom.1, wrjpgcom.1)
+in the man-page directory. The pre-fab makefiles don't support this step
+since there's such a wide variety of installation procedures on different
+systems.
+
+If you generated a Makefile with the "configure" script, you can just say
+ make install
+to install the programs and their man pages into the standard places.
+(You'll probably need to be root to do this.) We recommend first saying
+ make -n install
+to see where configure thought the files should go. You may need to edit
+the Makefile, particularly if your system's conventions for man page
+filenames don't match what configure expects.
+
+If you want to install the IJG library itself, for use in compiling other
+programs besides ours, then you need to put the four include files
+ jpeglib.h jerror.h jconfig.h jmorecfg.h
+into your include-file directory, and put the library file libjpeg.a
+(extension may vary depending on system) wherever library files go.
+If you generated a Makefile with "configure", it will do what it thinks
+is the right thing if you say
+ make install-lib
+
+
+OPTIONAL STUFF
+==============
+
+Progress monitor:
+
+If you like, you can #define PROGRESS_REPORT (in jconfig.h) to enable display
+of percent-done progress reports. The routine provided in cdjpeg.c merely
+prints percentages to stderr, but you can customize it to do something
+fancier.
+
+Utah RLE file format support:
+
+We distribute the software with support for RLE image files (Utah Raster
+Toolkit format) disabled, because the RLE support won't compile without the
+Utah library. If you have URT version 3.1 or later, you can enable RLE
+support as follows:
+ 1. #define RLE_SUPPORTED in jconfig.h.
+ 2. Add a -I option to CFLAGS in the Makefile for the directory
+ containing the URT .h files (typically the "include"
+ subdirectory of the URT distribution).
+ 3. Add -L... -lrle to LDLIBS in the Makefile, where ... specifies
+ the directory containing the URT "librle.a" file (typically the
+ "lib" subdirectory of the URT distribution).
+
+Support for 12-bit-deep pixel data:
+
+The JPEG standard allows either 8-bit or 12-bit data precision. (For color,
+this means 8 or 12 bits per channel, of course.) If you need to work with
+deeper than 8-bit data, you can compile the IJG code for 12-bit operation.
+To do so:
+ 1. In jmorecfg.h, define BITS_IN_JSAMPLE as 12 rather than 8.
+ 2. In jconfig.h, undefine BMP_SUPPORTED, RLE_SUPPORTED, and TARGA_SUPPORTED,
+ because the code for those formats doesn't handle 12-bit data and won't
+ even compile. (The PPM code does work, as explained below. The GIF
+ code works too; it scales 8-bit GIF data to and from 12-bit depth
+ automatically.)
+ 3. Compile. Don't expect "make test" to pass, since the supplied test
+ files are for 8-bit data.
+
+Currently, 12-bit support does not work on 16-bit-int machines.
+
+Note that a 12-bit version will not read 8-bit JPEG files, nor vice versa;
+so you'll want to keep around a regular 8-bit compilation as well.
+(Run-time selection of data depth, to allow a single copy that does both,
+is possible but would probably slow things down considerably; it's very low
+on our to-do list.)
+
+The PPM reader (rdppm.c) can read 12-bit data from either text-format or
+binary-format PPM and PGM files. Binary-format PPM/PGM files which have a
+maxval greater than 255 are assumed to use 2 bytes per sample, LSB first
+(little-endian order). As of early 1995, 2-byte binary format is not
+officially supported by the PBMPLUS library, but it is expected that a
+future release of PBMPLUS will support it. Note that the PPM reader will
+read files of any maxval regardless of the BITS_IN_JSAMPLE setting; incoming
+data is automatically rescaled to either maxval=255 or maxval=4095 as
+appropriate for the cjpeg bit depth.
+
+The PPM writer (wrppm.c) will normally write 2-byte binary PPM or PGM
+format, maxval 4095, when compiled with BITS_IN_JSAMPLE=12. Since this
+format is not yet widely supported, you can disable it by compiling wrppm.c
+with PPM_NORAWWORD defined; then the data is scaled down to 8 bits to make a
+standard 1-byte/sample PPM or PGM file. (Yes, this means still another copy
+of djpeg to keep around. But hopefully you won't need it for very long.
+Poskanzer's supposed to get that new PBMPLUS release out Real Soon Now.)
+
+Of course, if you are working with 12-bit data, you probably have it stored
+in some other, nonstandard format. In that case you'll probably want to
+write your own I/O modules to read and write your format.
+
+Note that a 12-bit version of cjpeg always runs in "-optimize" mode, in
+order to generate valid Huffman tables. This is necessary because our
+default Huffman tables only cover 8-bit data.
+
+Removing code:
+
+If you need to make a smaller version of the JPEG software, some optional
+functions can be removed at compile time. See the xxx_SUPPORTED #defines in
+jconfig.h and jmorecfg.h. If at all possible, we recommend that you leave in
+decoder support for all valid JPEG files, to ensure that you can read anyone's
+output. Taking out support for image file formats that you don't use is the
+most painless way to make the programs smaller. Another possibility is to
+remove some of the DCT methods: in particular, the "IFAST" method may not be
+enough faster than the others to be worth keeping on your machine. (If you
+do remove ISLOW or IFAST, be sure to redefine JDCT_DEFAULT or JDCT_FASTEST
+to a supported method, by adding a #define in jconfig.h.)
+
+
+OPTIMIZATION
+============
+
+Unless you own a Cray, you'll probably be interested in making the JPEG
+software go as fast as possible. This section covers some machine-dependent
+optimizations you may want to try. We suggest that before trying any of
+this, you first get the basic installation to pass the self-test step.
+Repeat the self-test after any optimization to make sure that you haven't
+broken anything.
+
+The integer DCT routines perform a lot of multiplications. These
+multiplications must yield 32-bit results, but none of their input values
+are more than 16 bits wide. On many machines, notably the 680x0 and 80x86
+CPUs, a 16x16=>32 bit multiply instruction is faster than a full 32x32=>32
+bit multiply. Unfortunately there is no portable way to specify such a
+multiplication in C, but some compilers can generate one when you use the
+right combination of casts. See the MULTIPLYxxx macro definitions in
+jdct.h. If your compiler makes "int" be 32 bits and "short" be 16 bits,
+defining SHORTxSHORT_32 is fairly likely to work. When experimenting with
+alternate definitions, be sure to test not only whether the code still works
+(use the self-test), but also whether it is actually faster --- on some
+compilers, alternate definitions may compute the right answer, yet be slower
+than the default. Timing cjpeg on a large PGM (grayscale) input file is the
+best way to check this, as the DCT will be the largest fraction of the runtime
+in that mode. (Note: some of the distributed compiler-specific jconfig files
+already contain #define switches to select appropriate MULTIPLYxxx
+definitions.)
+
+If your machine has sufficiently fast floating point hardware, you may find
+that the float DCT method is faster than the integer DCT methods, even
+after tweaking the integer multiply macros. In that case you may want to
+make the float DCT be the default method. (The only objection to this is
+that float DCT results may vary slightly across machines.) To do that, add
+"#define JDCT_DEFAULT JDCT_FLOAT" to jconfig.h. Even if you don't change
+the default, you should redefine JDCT_FASTEST, which is the method selected
+by djpeg's -fast switch. Don't forget to update the documentation files
+(usage.doc and/or cjpeg.1, djpeg.1) to agree with what you've done.
+
+If access to "short" arrays is slow on your machine, it may be a win to
+define type JCOEF as int rather than short. This will cost a good deal of
+memory though, particularly in some multi-pass modes, so don't do it unless
+you have memory to burn and short is REALLY slow.
+
+If your compiler can compile function calls in-line, make sure the INLINE
+macro in jmorecfg.h is defined as the keyword that marks a function
+inline-able. Some compilers have a switch that tells the compiler to inline
+any function it thinks is profitable (e.g., -finline-functions for gcc).
+Enabling such a switch is likely to make the compiled code bigger but faster.
+
+In general, it's worth trying the maximum optimization level of your compiler,
+and experimenting with any optional optimizations such as loop unrolling.
+(Unfortunately, far too many compilers have optimizer bugs ... be prepared to
+back off if the code fails self-test.) If you do any experimentation along
+these lines, please report the optimal settings to jpeg-info@uunet.uu.net so
+we can mention them in future releases. Be sure to specify your machine and
+compiler version.
+
+
+HINTS FOR SPECIFIC SYSTEMS
+==========================
+
+We welcome reports on changes needed for systems not mentioned here. Submit
+'em to jpeg-info@uunet.uu.net. Also, if configure or ckconfig.c is wrong
+about how to configure the JPEG software for your system, please let us know.
+
+
+Acorn RISC OS:
+
+(Thanks to Simon Middleton for these hints on compiling with Desktop C.)
+After renaming the files according to Acorn conventions, take a copy of
+makefile.ansi, change all occurrences of 'libjpeg.a' to 'libjpeg.o' and
+change these definitions as indicated:
+
+CFLAGS= -throwback -IC: -Wn
+LDLIBS=C:o.Stubs
+SYSDEPMEM=jmemansi.o
+LN=Link
+AR=LibFile -c -o
+
+Also add a new line '.c.o:; $(cc) $< $(cflags) -c -o $@'. Remove the
+lines '$(RM) libjpeg.o' and '$(AR2) libjpeg.o' and the 'jconfig.h'
+dependency section.
+
+Copy jconfig.doc to jconfig.h. Edit jconfig.h to define TWO_FILE_COMMANDLINE
+and CHAR_IS_UNSIGNED.
+
+Run the makefile using !AMU not !Make. If you want to use the 'clean' and
+'test' makefile entries then you will have to fiddle with the syntax a bit
+and rename the test files.
+
+
+Amiga:
+
+SAS C 6.50 reportedly is too buggy to compile the IJG code properly.
+A patch to update to 6.51 is available from SAS or AmiNet FTP sites.
+
+The supplied config files are set up to use jmemname.c as the memory
+manager, with temporary files being created on the device named by
+"JPEGTMP:".
+
+
+Atari ST/STE/TT:
+
+Copy the project files makcjpeg.st, makdjpeg.st, maktjpeg.st, and makljpeg.st
+to cjpeg.prj, djpeg.prj, jpegtran.prj, and libjpeg.prj respectively. The
+project files should work as-is with Pure C. For Turbo C, change library
+filenames "pc..." to "tc..." in each project file. Note that libjpeg.prj
+selects jmemansi.c as the recommended memory manager. You'll probably want to
+adjust the DEFAULT_MAX_MEM setting --- you want it to be a couple hundred K
+less than your normal free memory. Put "#define DEFAULT_MAX_MEM nnnn" into
+jconfig.h to do this.
+
+To use the 68881/68882 coprocessor for the floating point DCT, add the
+compiler option "-8" to the project files and replace pcfltlib.lib with
+pc881lib.lib in cjpeg.prj and djpeg.prj. Or if you don't have a
+coprocessor, you may prefer to remove the float DCT code by undefining
+DCT_FLOAT_SUPPORTED in jmorecfg.h (since without a coprocessor, the float
+code will be too slow to be useful). In that case, you can delete
+pcfltlib.lib from the project files.
+
+Note that you must make libjpeg.lib before making cjpeg.ttp, djpeg.ttp,
+or jpegtran.ttp. You'll have to perform the self-test by hand.
+
+We haven't bothered to include project files for rdjpgcom and wrjpgcom.
+Those source files should just be compiled by themselves; they don't
+depend on the JPEG library.
+
+There is a bug in some older versions of the Turbo C library which causes the
+space used by temporary files created with "tmpfile()" not to be freed after
+an abnormal program exit. If you check your disk afterwards, you will find
+cluster chains that are allocated but not used by a file. This should not
+happen in cjpeg/djpeg/jpegtran, since we enable a signal catcher to explicitly
+close temp files before exiting. But if you use the JPEG library with your
+own code, be sure to supply a signal catcher, or else use a different
+system-dependent memory manager.
+
+
+Cray:
+
+Should you be so fortunate as to be running JPEG on a Cray YMP, there is a
+compiler bug in old versions of Cray's Standard C (prior to 3.1). If you
+still have an old compiler, you'll need to insert a line reading
+"#pragma novector" just before the loop
+ for (i = 1; i <= (int) htbl->bits[l]; i++)
+ huffsize[p++] = (char) l;
+in fix_huff_tbl (in V5beta1, line 204 of jchuff.c and line 176 of jdhuff.c).
+[This bug may or may not still occur with the current IJG code, but it's
+probably a dead issue anyway...]
+
+
+HP-UX:
+
+If you have HP-UX 7.05 or later with the "software development" C compiler,
+you should run the compiler in ANSI mode. If using the configure script,
+say
+ ./configure CC='cc -Aa'
+(or -Ae if you prefer). If configuring by hand, use makefile.ansi and add
+"-Aa" to the CFLAGS line in the makefile.
+
+If you have a pre-7.05 system, or if you are using the non-ANSI C compiler
+delivered with a minimum HP-UX system, then you must use makefile.unix
+(and do NOT add -Aa); or just run configure without the CC option.
+
+On HP 9000 series 800 machines, the HP C compiler is buggy in revisions prior
+to A.08.07. If you get complaints about "not a typedef name", you'll have to
+use makefile.unix, or run configure without the CC option.
+
+
+Macintosh, generic comments:
+
+The supplied user-interface files (cjpeg.c, djpeg.c, etc) are set up to
+provide a Unix-style command line interface. You can use this interface on
+the Mac by means of the ccommand() library routine provided by Metrowerks
+CodeWarrior or Think C. This is only appropriate for testing the library,
+however; to make a user-friendly equivalent of cjpeg/djpeg you'd really want
+to develop a Mac-style user interface. There isn't a complete example
+available at the moment, but there are some helpful starting points:
+1. Sam Bushell's free "To JPEG" applet provides drag-and-drop conversion to
+JPEG under System 7 and later. This only illustrates how to use the
+compression half of the library, but it does a very nice job of that part.
+The CodeWarrior source code is available from http://www.pobox.com/~jsam.
+2. Jim Brunner prepared a Mac-style user interface for both compression and
+decompression. Unfortunately, it hasn't been updated since IJG v4, and
+the library's API has changed considerably since then. Still it may be of
+some help, particularly as a guide to compiling the IJG code under Think C.
+Jim's code is available from the Info-Mac archives, at sumex-aim.stanford.edu
+or mirrors thereof; see file /info-mac/dev/src/jpeg-convert-c.hqx.
+
+jmemmac.c is the recommended memory manager back end for Macintosh. It uses
+NewPtr/DisposePtr instead of malloc/free, and has a Mac-specific
+implementation of jpeg_mem_available(). It also creates temporary files that
+follow Mac conventions. (That part of the code relies on System-7-or-later OS
+functions. See the comments in jmemmac.c if you need to run it on System 6.)
+NOTE that USE_MAC_MEMMGR must be defined in jconfig.h to use jmemmac.c.
+
+You can also use jmemnobs.c, if you don't care about handling images larger
+than available memory. If you use any memory manager back end other than
+jmemmac.c, we recommend replacing "malloc" and "free" by "NewPtr" and
+"DisposePtr", because Mac C libraries often have peculiar implementations of
+malloc/free. (For instance, free() may not return the freed space to the
+Mac Memory Manager. This is undesirable for the IJG code because jmemmgr.c
+already clumps space requests.)
+
+
+Macintosh, Metrowerks CodeWarrior:
+
+The Unix-command-line-style interface can be used by defining USE_CCOMMAND.
+You'll also need to define TWO_FILE_COMMANDLINE to avoid stdin/stdout.
+This means that when using the cjpeg/djpeg programs, you'll have to type the
+input and output file names in the "Arguments" text-edit box, rather than
+using the file radio buttons. (Perhaps USE_FDOPEN or USE_SETMODE would
+eliminate the problem, but I haven't heard from anyone who's tried it.)
+
+On 680x0 Macs, Metrowerks defines type "double" as a 10-byte IEEE extended
+float. jmemmgr.c won't like this: it wants sizeof(ALIGN_TYPE) to be a power
+of 2. Add "#define ALIGN_TYPE long" to jconfig.h to eliminate the complaint.
+
+The supplied configuration file jconfig.mac can be used for your jconfig.h;
+it includes all the recommended symbol definitions. If you have AppleScript
+installed, you can run the supplied script makeproj.mac to create CodeWarrior
+project files for the library and the testbed applications, then build the
+library and applications. (Thanks to Dan Sears and Don Agro for this nifty
+hack, which saves us from trying to maintain CodeWarrior project files as part
+of the IJG distribution...)
+
+
+Macintosh, Think C:
+
+The documentation in Jim Brunner's "JPEG Convert" source code (see above)
+includes detailed build instructions for Think C; it's probably somewhat
+out of date for the current release, but may be helpful.
+
+If you want to build the minimal command line version, proceed as follows.
+You'll have to prepare project files for the programs; we don't include any
+in the distribution since they are not text files. Use the file lists in
+any of the supplied makefiles as a guide. Also add the ANSI and Unix C
+libraries in a separate segment. You may need to divide the JPEG files into
+more than one segment; we recommend dividing compression and decompression
+modules. Define USE_CCOMMAND in jconfig.h so that the ccommand() routine is
+called. You must also define TWO_FILE_COMMANDLINE because stdin/stdout
+don't handle binary data correctly.
+
+On 680x0 Macs, Think C defines type "double" as a 12-byte IEEE extended float.
+jmemmgr.c won't like this: it wants sizeof(ALIGN_TYPE) to be a power of 2.
+Add "#define ALIGN_TYPE long" to jconfig.h to eliminate the complaint.
+
+jconfig.mac should work as a jconfig.h configuration file for Think C,
+but the makeproj.mac AppleScript script is specific to CodeWarrior. Sorry.
+
+
+MIPS R3000:
+
+MIPS's cc version 1.31 has a rather nasty optimization bug. Don't use -O
+if you have that compiler version. (Use "cc -V" to check the version.)
+Note that the R3000 chip is found in workstations from DEC and others.
+
+
+MS-DOS, generic comments for 16-bit compilers:
+
+The IJG code is designed to work well in 80x86 "small" or "medium" memory
+models (i.e., data pointers are 16 bits unless explicitly declared "far";
+code pointers can be either size). You may be able to use small model to
+compile cjpeg or djpeg by itself, but you will probably have to use medium
+model for any larger application. This won't make much difference in
+performance. You *will* take a noticeable performance hit if you use a
+large-data memory model, and you should avoid "huge" model if at all
+possible. Be sure that NEED_FAR_POINTERS is defined in jconfig.h if you use
+a small-data memory model; be sure it is NOT defined if you use a large-data
+model. (The supplied makefiles and jconfig files for Borland and Microsoft C
+compile in medium model and define NEED_FAR_POINTERS.)
+
+The DOS-specific memory manager, jmemdos.c, should be used if possible.
+It needs some assembly-code routines which are in jmemdosa.asm; make sure
+your makefile assembles that file and includes it in the library. If you
+don't have a suitable assembler, you can get pre-assembled object files for
+jmemdosa by FTP from ftp.uu.net:/graphics/jpeg/jdosaobj.zip. (DOS-oriented
+distributions of the IJG source code often include these object files.)
+
+When using jmemdos.c, jconfig.h must define USE_MSDOS_MEMMGR and must set
+MAX_ALLOC_CHUNK to less than 64K (65520L is a typical value). If your
+C library's far-heap malloc() can't allocate blocks that large, reduce
+MAX_ALLOC_CHUNK to whatever it can handle.
+
+If you can't use jmemdos.c for some reason --- for example, because you
+don't have an assembler to assemble jmemdosa.asm --- you'll have to fall
+back to jmemansi.c or jmemname.c. You'll probably still need to set
+MAX_ALLOC_CHUNK in jconfig.h, because most DOS C libraries won't malloc()
+more than 64K at a time. IMPORTANT: if you use jmemansi.c or jmemname.c,
+you will have to compile in a large-data memory model in order to get the
+right stdio library. Too bad.
+
+wrjpgcom needs to be compiled in large model, because it malloc()s a 64KB
+work area to hold the comment text. If your C library's malloc can't
+handle that, reduce MAX_COM_LENGTH as necessary in wrjpgcom.c.
+
+Most MS-DOS compilers treat stdin/stdout as text files, so you must use
+two-file command line style. But if your compiler has either fdopen() or
+setmode(), you can use one-file style if you like. To do this, define
+USE_SETMODE or USE_FDOPEN so that stdin/stdout will be set to binary mode.
+(USE_SETMODE seems to work with more DOS compilers than USE_FDOPEN.) You
+should test that I/O through stdin/stdout produces the same results as I/O
+to explicitly named files... the "make test" procedures in the supplied
+makefiles do NOT use stdin/stdout.
+
+
+MS-DOS, generic comments for 32-bit compilers:
+
+None of the above comments about memory models apply if you are using a
+32-bit flat-memory-space environment, such as DJGPP or Watcom C. (And you
+should use one if you have it, as performance will be much better than
+8086-compatible code!) For flat-memory-space compilers, do NOT define
+NEED_FAR_POINTERS, and do NOT use jmemdos.c. Use jmemnobs.c if the
+environment supplies adequate virtual memory, otherwise use jmemansi.c or
+jmemname.c.
+
+You'll still need to be careful about binary I/O through stdin/stdout.
+See the last paragraph of the previous section.
+
+
+MS-DOS, Borland C:
+
+Be sure to convert all the source files to DOS text format (CR/LF newlines).
+Although Borland C will often work OK with unmodified Unix (LF newlines)
+source files, sometimes it will give bogus compile errors.
+"Illegal character '#'" is the most common such error. (This is true with
+Borland C 3.1, but perhaps is fixed in newer releases.)
+
+If you want one-file command line style, just undefine TWO_FILE_COMMANDLINE.
+jconfig.bcc already includes #define USE_SETMODE to make this work.
+(fdopen does not work correctly.)
+
+
+MS-DOS, Microsoft C:
+
+makefile.mc6 works with Microsoft C, DOS Visual C++, etc. It should only
+be used if you want to build a 16-bit (small or medium memory model) program.
+
+If you want one-file command line style, just undefine TWO_FILE_COMMANDLINE.
+jconfig.mc6 already includes #define USE_SETMODE to make this work.
+(fdopen does not work correctly.)
+
+Note that this makefile assumes that the working copy of itself is called
+"makefile". If you want to call it something else, say "makefile.mak",
+be sure to adjust the dependency line that reads "$(RFILE) : makefile".
+Otherwise the make will fail because it doesn't know how to create "makefile".
+Worse, some releases of Microsoft's make utilities give an incorrect error
+message in this situation.
+
+Old versions of MS C fail with an "out of macro expansion space" error
+because they can't cope with the macro TRACEMS8 (defined in jerror.h).
+If this happens to you, the easiest solution is to change TRACEMS8 to
+expand to nothing. You'll lose the ability to dump out JPEG coefficient
+tables with djpeg -debug -debug, but at least you can compile.
+
+Original MS C 6.0 is very buggy; it compiles incorrect code unless you turn
+off optimization entirely (remove -O from CFLAGS). 6.00A is better, but it
+still generates bad code if you enable loop optimizations (-Ol or -Ox).
+
+MS C 8.0 crashes when compiling jquant1.c with optimization switch /Oo ...
+which is on by default. To work around this bug, compile that one file
+with /Oo-.
+
+
+Microsoft Windows (all versions), generic comments:
+
+Some Windows system include files define typedef boolean as "unsigned char".
+The IJG code also defines typedef boolean, but we make it "int" by default.
+This doesn't affect the IJG programs because we don't import those Windows
+include files. But if you use the JPEG library in your own program, and some
+of your program's files import one definition of boolean while some import the
+other, you can get all sorts of mysterious problems. A good preventive step
+is to make the IJG library use "unsigned char" for boolean. To do that,
+add something like this to your jconfig.h file:
+ /* Define "boolean" as unsigned char, not int, per Windows custom */
+ #ifndef __RPCNDR_H__ /* don't conflict if rpcndr.h already read */
+ typedef unsigned char boolean;
+ #endif
+ #define HAVE_BOOLEAN /* prevent jmorecfg.h from redefining it */
+(This is already in jconfig.vc, by the way.)
+
+windef.h contains the declarations
+ #define far
+ #define FAR far
+Since jmorecfg.h tries to define FAR as empty, you may get a compiler
+warning if you include both jpeglib.h and windef.h (which windows.h
+includes). To suppress the warning, you can put "#ifndef FAR"/"#endif"
+around the line "#define FAR" in jmorecfg.h.
+
+When using the library in a Windows application, you will almost certainly
+want to modify or replace the error handler module jerror.c, since our
+default error handler does a couple of inappropriate things:
+ 1. it tries to write error and warning messages on stderr;
+ 2. in event of a fatal error, it exits by calling exit().
+
+A simple stopgap solution for problem 1 is to replace the line
+ fprintf(stderr, "%s\n", buffer);
+(in output_message in jerror.c) with
+ MessageBox(GetActiveWindow(),buffer,"JPEG Error",MB_OK|MB_ICONERROR);
+It's highly recommended that you at least do that much, since otherwise
+error messages will disappear into nowhere. (Beginning with IJG v6b, this
+code is already present in jerror.c; just define USE_WINDOWS_MESSAGEBOX in
+jconfig.h to enable it.)
+
+The proper solution for problem 2 is to return control to your calling
+application after a library error. This can be done with the setjmp/longjmp
+technique discussed in libjpeg.doc and illustrated in example.c. (NOTE:
+some older Windows C compilers provide versions of setjmp/longjmp that
+don't actually work under Windows. You may need to use the Windows system
+functions Catch and Throw instead.)
+
+The recommended memory manager under Windows is jmemnobs.c; in other words,
+let Windows do any virtual memory management needed. You should NOT use
+jmemdos.c nor jmemdosa.asm under Windows.
+
+For Windows 3.1, we recommend compiling in medium or large memory model;
+for newer Windows versions, use a 32-bit flat memory model. (See the MS-DOS
+sections above for more info about memory models.) In the 16-bit memory
+models only, you'll need to put
+ #define MAX_ALLOC_CHUNK 65520L /* Maximum request to malloc() */
+into jconfig.h to limit allocation chunks to 64Kb. (Without that, you'd
+have to use huge memory model, which slows things down unnecessarily.)
+jmemnobs.c works without modification in large or flat memory models, but to
+use medium model, you need to modify its jpeg_get_large and jpeg_free_large
+routines to allocate far memory. In any case, you might like to replace
+its calls to malloc and free with direct calls on Windows memory allocation
+functions.
+
+You may also want to modify jdatasrc.c and jdatadst.c to use Windows file
+operations rather than fread/fwrite. This is only necessary if your C
+compiler doesn't provide a competent implementation of C stdio functions.
+
+You might want to tweak the RGB_xxx macros in jmorecfg.h so that the library
+will accept or deliver color pixels in BGR sample order, not RGB; BGR order
+is usually more convenient under Windows. Note that this change will break
+the sample applications cjpeg/djpeg, but the library itself works fine.
+
+
+Many people want to convert the IJG library into a DLL. This is reasonably
+straightforward, but watch out for the following:
+
+ 1. Don't try to compile as a DLL in small or medium memory model; use
+large model, or even better, 32-bit flat model. Many places in the IJG code
+assume the address of a local variable is an ordinary (not FAR) pointer;
+that isn't true in a medium-model DLL.
+
+ 2. Microsoft C cannot pass file pointers between applications and DLLs.
+(See Microsoft Knowledge Base, PSS ID Number Q50336.) So jdatasrc.c and
+jdatadst.c don't work if you open a file in your application and then pass
+the pointer to the DLL. One workaround is to make jdatasrc.c/jdatadst.c
+part of your main application rather than part of the DLL.
+
+ 3. You'll probably need to modify the macros GLOBAL() and EXTERN() to
+attach suitable linkage keywords to the exported routine names. Similarly,
+you'll want to modify METHODDEF() and JMETHOD() to ensure function pointers
+are declared in a way that lets application routines be called back through
+the function pointers. These macros are in jmorecfg.h. Typical definitions
+for a 16-bit DLL are:
+ #define GLOBAL(type) type _far _pascal _loadds _export
+ #define EXTERN(type) extern type _far _pascal _loadds
+ #define METHODDEF(type) static type _far _pascal
+ #define JMETHOD(type,methodname,arglist) \
+ type (_far _pascal *methodname) arglist
+For a 32-bit DLL you may want something like
+ #define GLOBAL(type) __declspec(dllexport) type
+ #define EXTERN(type) extern __declspec(dllexport) type
+Although not all the GLOBAL routines are actually intended to be called by
+the application, the performance cost of making them all DLL entry points is
+negligible.
+
+The unmodified IJG library presents a very C-specific application interface,
+so the resulting DLL is only usable from C or C++ applications. There has
+been some talk of writing wrapper code that would present a simpler interface
+usable from other languages, such as Visual Basic. This is on our to-do list
+but hasn't been very high priority --- any volunteers out there?
+
+
+Microsoft Windows, Borland C:
+
+The provided jconfig.bcc should work OK in a 32-bit Windows environment,
+but you'll need to tweak it in a 16-bit environment (you'd need to define
+NEED_FAR_POINTERS and MAX_ALLOC_CHUNK). Beware that makefile.bcc will need
+alteration if you want to use it for Windows --- in particular, you should
+use jmemnobs.c not jmemdos.c under Windows.
+
+Borland C++ 4.5 fails with an internal compiler error when trying to compile
+jdmerge.c in 32-bit mode. If enough people complain, perhaps Borland will fix
+it. In the meantime, the simplest known workaround is to add a redundant
+definition of the variable range_limit in h2v1_merged_upsample(), at the head
+of the block that handles odd image width (about line 268 in v6 jdmerge.c):
+ /* If image width is odd, do the last output column separately */
+ if (cinfo->output_width & 1) {
+ register JSAMPLE * range_limit = cinfo->sample_range_limit; /* ADD THIS */
+ cb = GETJSAMPLE(*inptr1);
+Pretty bizarre, especially since the very similar routine h2v2_merged_upsample
+doesn't trigger the bug.
+Recent reports suggest that this bug does not occur with "bcc32a" (the
+Pentium-optimized version of the compiler).
+
+Another report from a user of Borland C 4.5 was that incorrect code (leading
+to a color shift in processed images) was produced if any of the following
+optimization switch combinations were used:
+ -Ot -Og
+ -Ot -Op
+ -Ot -Om
+So try backing off on optimization if you see such a problem. (Are there
+several different releases all numbered "4.5"??)
+
+
+Microsoft Windows, Microsoft Visual C++:
+
+jconfig.vc should work OK with any Microsoft compiler for a 32-bit memory
+model. makefile.vc is intended for command-line use. (If you are using
+the Developer Studio environment, you may prefer the DevStudio project
+files; see below.)
+
+Some users feel that it's easier to call the library from C++ code if you
+force VC++ to treat the library as C++ code, which you can do by renaming
+all the *.c files to *.cpp (and adjusting the makefile to match). This
+avoids the need to put extern "C" { ... } around #include "jpeglib.h" in
+your C++ application.
+
+
+Microsoft Windows, Microsoft Developer Studio:
+
+We include makefiles that should work as project files in DevStudio 4.2 or
+later. There is a library makefile that builds the IJG library as a static
+Win32 library, and an application makefile that builds the sample applications
+as Win32 console applications. (Even if you only want the library, we
+recommend building the applications so that you can run the self-test.)
+
+To use:
+1. Copy jconfig.vc to jconfig.h, makelib.ds to jpeg.mak, and
+ makeapps.ds to apps.mak. (Note that the renaming is critical!)
+2. Click on the .mak files to construct project workspaces.
+ (If you are using DevStudio more recent than 4.2, you'll probably
+ get a message saying that the makefiles are being updated.)
+3. Build the library project, then the applications project.
+4. Move the application .exe files from `app`\Release to an
+ appropriate location on your path.
+5. To perform the self-test, execute the command line
+ NMAKE /f makefile.vc test
+
+
+OS/2, Borland C++:
+
+Watch out for optimization bugs in older Borland compilers; you may need
+to back off the optimization switch settings. See the comments in
+makefile.bcc.
+
+
+SGI:
+
+On some SGI systems, you may need to set "AR2= ar -ts" in the Makefile.
+If you are using configure, you can do this by saying
+ ./configure RANLIB='ar -ts'
+This change is not needed on all SGIs. Use it only if the make fails at the
+stage of linking the completed programs.
+
+On the MIPS R4000 architecture (Indy, etc.), the compiler option "-mips2"
+reportedly speeds up the float DCT method substantially, enough to make it
+faster than the default int method (but still slower than the fast int
+method). If you use -mips2, you may want to alter the default DCT method to
+be float. To do this, put "#define JDCT_DEFAULT JDCT_FLOAT" in jconfig.h.
+
+
+VMS:
+
+On an Alpha/VMS system with MMS, be sure to use the "/Marco=Alpha=1"
+qualifier with MMS when building the JPEG package.
+
+VAX/VMS v5.5-1 may have problems with the test step of the build procedure
+reporting differences when it compares the original and test images. If the
+error points to the last block of the files, it is most likely bogus and may
+be safely ignored. It seems to be because the files are Stream_LF and
+Backup/Compare has difficulty with the (presumably) null padded files.
+This problem was not observed on VAX/VMS v6.1 or AXP/VMS v6.1.
--- /dev/null
+/*
+ * jaricom.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file holds place for arithmetic entropy codec tables.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+INT32 jaritab[1]; /* dummy table */
--- /dev/null
+/*
+ * jcapimin.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains application interface code for the compression half
+ * of the JPEG library. These are the "minimum" API routines that may be
+ * needed in either the normal full-compression case or the transcoding-only
+ * case.
+ *
+ * Most of the routines intended to be called directly by an application
+ * are in this file or in jcapistd.c. But also see jcparam.c for
+ * parameter-setup helper routines, jcomapi.c for routines shared by
+ * compression and decompression, and jctrans.c for the transcoding case.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Initialization of a JPEG compression object.
+ * The error manager must already be set up (in case memory manager fails).
+ */
+
+GLOBAL(void)
+jpeg_CreateCompress (j_compress_ptr cinfo, int version, size_t structsize)
+{
+ int i;
+
+ /* Guard against version mismatches between library and caller. */
+ cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */
+ if (version != JPEG_LIB_VERSION)
+ ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
+ if (structsize != SIZEOF(struct jpeg_compress_struct))
+ ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
+ (int) SIZEOF(struct jpeg_compress_struct), (int) structsize);
+
+ /* For debugging purposes, we zero the whole master structure.
+ * But the application has already set the err pointer, and may have set
+ * client_data, so we have to save and restore those fields.
+ * Note: if application hasn't set client_data, tools like Purify may
+ * complain here.
+ */
+ {
+ struct jpeg_error_mgr * err = cinfo->err;
+ void * client_data = cinfo->client_data; /* ignore Purify complaint here */
+ MEMZERO(cinfo, SIZEOF(struct jpeg_compress_struct));
+ cinfo->err = err;
+ cinfo->client_data = client_data;
+ }
+ cinfo->is_decompressor = FALSE;
+
+ /* Initialize a memory manager instance for this object */
+ jinit_memory_mgr((j_common_ptr) cinfo);
+
+ /* Zero out pointers to permanent structures. */
+ cinfo->progress = NULL;
+ cinfo->dest = NULL;
+
+ cinfo->comp_info = NULL;
+
+ for (i = 0; i < NUM_QUANT_TBLS; i++)
+ cinfo->quant_tbl_ptrs[i] = NULL;
+
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ cinfo->dc_huff_tbl_ptrs[i] = NULL;
+ cinfo->ac_huff_tbl_ptrs[i] = NULL;
+ }
+
+ cinfo->script_space = NULL;
+
+ cinfo->input_gamma = 1.0; /* in case application forgets */
+
+ /* OK, I'm ready */
+ cinfo->global_state = CSTATE_START;
+}
+
+
+/*
+ * Destruction of a JPEG compression object
+ */
+
+GLOBAL(void)
+jpeg_destroy_compress (j_compress_ptr cinfo)
+{
+ jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
+}
+
+
+/*
+ * Abort processing of a JPEG compression operation,
+ * but don't destroy the object itself.
+ */
+
+GLOBAL(void)
+jpeg_abort_compress (j_compress_ptr cinfo)
+{
+ jpeg_abort((j_common_ptr) cinfo); /* use common routine */
+}
+
+
+/*
+ * Forcibly suppress or un-suppress all quantization and Huffman tables.
+ * Marks all currently defined tables as already written (if suppress)
+ * or not written (if !suppress). This will control whether they get emitted
+ * by a subsequent jpeg_start_compress call.
+ *
+ * This routine is exported for use by applications that want to produce
+ * abbreviated JPEG datastreams. It logically belongs in jcparam.c, but
+ * since it is called by jpeg_start_compress, we put it here --- otherwise
+ * jcparam.o would be linked whether the application used it or not.
+ */
+
+GLOBAL(void)
+jpeg_suppress_tables (j_compress_ptr cinfo, boolean suppress)
+{
+ int i;
+ JQUANT_TBL * qtbl;
+ JHUFF_TBL * htbl;
+
+ for (i = 0; i < NUM_QUANT_TBLS; i++) {
+ if ((qtbl = cinfo->quant_tbl_ptrs[i]) != NULL)
+ qtbl->sent_table = suppress;
+ }
+
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ if ((htbl = cinfo->dc_huff_tbl_ptrs[i]) != NULL)
+ htbl->sent_table = suppress;
+ if ((htbl = cinfo->ac_huff_tbl_ptrs[i]) != NULL)
+ htbl->sent_table = suppress;
+ }
+}
+
+
+/*
+ * Finish JPEG compression.
+ *
+ * If a multipass operating mode was selected, this may do a great deal of
+ * work including most of the actual output.
+ */
+
+GLOBAL(void)
+jpeg_finish_compress (j_compress_ptr cinfo)
+{
+ JDIMENSION iMCU_row;
+
+ if (cinfo->global_state == CSTATE_SCANNING ||
+ cinfo->global_state == CSTATE_RAW_OK) {
+ /* Terminate first pass */
+ if (cinfo->next_scanline < cinfo->image_height)
+ ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
+ (*cinfo->master->finish_pass) (cinfo);
+ } else if (cinfo->global_state != CSTATE_WRCOEFS)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ /* Perform any remaining passes */
+ while (! cinfo->master->is_last_pass) {
+ (*cinfo->master->prepare_for_pass) (cinfo);
+ for (iMCU_row = 0; iMCU_row < cinfo->total_iMCU_rows; iMCU_row++) {
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) iMCU_row;
+ cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+ /* We bypass the main controller and invoke coef controller directly;
+ * all work is being done from the coefficient buffer.
+ */
+ if (! (*cinfo->codec->compress_data) (cinfo, (JSAMPIMAGE) NULL))
+ ERREXIT(cinfo, JERR_CANT_SUSPEND);
+ }
+ (*cinfo->master->finish_pass) (cinfo);
+ }
+ /* Write EOI, do final cleanup */
+ (*cinfo->marker->write_file_trailer) (cinfo);
+ (*cinfo->dest->term_destination) (cinfo);
+ /* We can use jpeg_abort to release memory and reset global_state */
+ jpeg_abort((j_common_ptr) cinfo);
+}
+
+
+/*
+ * Write a special marker.
+ * This is only recommended for writing COM or APPn markers.
+ * Must be called after jpeg_start_compress() and before
+ * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
+ */
+
+GLOBAL(void)
+jpeg_write_marker (j_compress_ptr cinfo, int marker,
+ const JOCTET *dataptr, unsigned int datalen)
+{
+ JMETHOD(void, write_marker_byte, (j_compress_ptr info, int val));
+
+ if (cinfo->next_scanline != 0 ||
+ (cinfo->global_state != CSTATE_SCANNING &&
+ cinfo->global_state != CSTATE_RAW_OK &&
+ cinfo->global_state != CSTATE_WRCOEFS))
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
+ write_marker_byte = cinfo->marker->write_marker_byte; /* copy for speed */
+ while (datalen--) {
+ (*write_marker_byte) (cinfo, *dataptr);
+ dataptr++;
+ }
+}
+
+/* Same, but piecemeal. */
+
+GLOBAL(void)
+jpeg_write_m_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
+{
+ if (cinfo->next_scanline != 0 ||
+ (cinfo->global_state != CSTATE_SCANNING &&
+ cinfo->global_state != CSTATE_RAW_OK &&
+ cinfo->global_state != CSTATE_WRCOEFS))
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ (*cinfo->marker->write_marker_header) (cinfo, marker, datalen);
+}
+
+GLOBAL(void)
+jpeg_write_m_byte (j_compress_ptr cinfo, int val)
+{
+ (*cinfo->marker->write_marker_byte) (cinfo, val);
+}
+
+
+/*
+ * Alternate compression function: just write an abbreviated table file.
+ * Before calling this, all parameters and a data destination must be set up.
+ *
+ * To produce a pair of files containing abbreviated tables and abbreviated
+ * image data, one would proceed as follows:
+ *
+ * initialize JPEG object
+ * set JPEG parameters
+ * set destination to table file
+ * jpeg_write_tables(cinfo);
+ * set destination to image file
+ * jpeg_start_compress(cinfo, FALSE);
+ * write data...
+ * jpeg_finish_compress(cinfo);
+ *
+ * jpeg_write_tables has the side effect of marking all tables written
+ * (same as jpeg_suppress_tables(..., TRUE)). Thus a subsequent start_compress
+ * will not re-emit the tables unless it is passed write_all_tables=TRUE.
+ */
+
+GLOBAL(void)
+jpeg_write_tables (j_compress_ptr cinfo)
+{
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ /* (Re)initialize error mgr and destination modules */
+ (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
+ (*cinfo->dest->init_destination) (cinfo);
+ /* Initialize the marker writer ... bit of a crock to do it here. */
+ jinit_marker_writer(cinfo);
+ /* Write them tables! */
+ (*cinfo->marker->write_tables_only) (cinfo);
+ /* And clean up. */
+ (*cinfo->dest->term_destination) (cinfo);
+ /*
+ * In library releases up through v6a, we called jpeg_abort() here to free
+ * any working memory allocated by the destination manager and marker
+ * writer. Some applications had a problem with that: they allocated space
+ * of their own from the library memory manager, and didn't want it to go
+ * away during write_tables. So now we do nothing. This will cause a
+ * memory leak if an app calls write_tables repeatedly without doing a full
+ * compression cycle or otherwise resetting the JPEG object. However, that
+ * seems less bad than unexpectedly freeing memory in the normal case.
+ * An app that prefers the old behavior can call jpeg_abort for itself after
+ * each call to jpeg_write_tables().
+ */
+}
--- /dev/null
+/*
+ * jcapistd.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains application interface code for the compression half
+ * of the JPEG library. These are the "standard" API routines that are
+ * used in the normal full-compression case. They are not used by a
+ * transcoding-only application. Note that if an application links in
+ * jpeg_start_compress, it will end up linking in the entire compressor.
+ * We thus must separate this file from jcapimin.c to avoid linking the
+ * whole compression library into a transcoder.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Compression initialization.
+ * Before calling this, all parameters and a data destination must be set up.
+ *
+ * We require a write_all_tables parameter as a failsafe check when writing
+ * multiple datastreams from the same compression object. Since prior runs
+ * will have left all the tables marked sent_table=TRUE, a subsequent run
+ * would emit an abbreviated stream (no tables) by default. This may be what
+ * is wanted, but for safety's sake it should not be the default behavior:
+ * programmers should have to make a deliberate choice to emit abbreviated
+ * images. Therefore the documentation and examples should encourage people
+ * to pass write_all_tables=TRUE; then it will take active thought to do the
+ * wrong thing.
+ */
+
+GLOBAL(void)
+jpeg_start_compress (j_compress_ptr cinfo, boolean write_all_tables)
+{
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ if (write_all_tables)
+ jpeg_suppress_tables(cinfo, FALSE); /* mark all tables to be written */
+
+ /* (Re)initialize error mgr and destination modules */
+ (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
+ (*cinfo->dest->init_destination) (cinfo);
+ /* Perform master selection of active modules */
+ jinit_compress_master(cinfo);
+ /* Set up for the first pass */
+ (*cinfo->master->prepare_for_pass) (cinfo);
+ /* Ready for application to drive first pass through jpeg_write_scanlines
+ * or jpeg_write_raw_data.
+ */
+ cinfo->next_scanline = 0;
+ cinfo->global_state = (cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING);
+}
+
+
+/*
+ * Write some scanlines of data to the JPEG compressor.
+ *
+ * The return value will be the number of lines actually written.
+ * This should be less than the supplied num_lines only in case that
+ * the data destination module has requested suspension of the compressor,
+ * or if more than image_height scanlines are passed in.
+ *
+ * Note: we warn about excess calls to jpeg_write_scanlines() since
+ * this likely signals an application programmer error. However,
+ * excess scanlines passed in the last valid call are *silently* ignored,
+ * so that the application need not adjust num_lines for end-of-image
+ * when using a multiple-scanline buffer.
+ */
+
+GLOBAL(JDIMENSION)
+jpeg_write_scanlines (j_compress_ptr cinfo, JSAMPARRAY scanlines,
+ JDIMENSION num_lines)
+{
+ JDIMENSION row_ctr, rows_left;
+
+ if (cinfo->global_state != CSTATE_SCANNING)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ if (cinfo->next_scanline >= cinfo->image_height)
+ WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
+
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->next_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->image_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+
+ /* Give master control module another chance if this is first call to
+ * jpeg_write_scanlines. This lets output of the frame/scan headers be
+ * delayed so that application can write COM, etc, markers between
+ * jpeg_start_compress and jpeg_write_scanlines.
+ */
+ if (cinfo->master->call_pass_startup)
+ (*cinfo->master->pass_startup) (cinfo);
+
+ /* Ignore any extra scanlines at bottom of image. */
+ rows_left = cinfo->image_height - cinfo->next_scanline;
+ if (num_lines > rows_left)
+ num_lines = rows_left;
+
+ row_ctr = 0;
+ (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, num_lines);
+ cinfo->next_scanline += row_ctr;
+ return row_ctr;
+}
+
+
+/*
+ * Alternate entry point to write raw data.
+ * Processes exactly one iMCU row per call, unless suspended.
+ */
+
+GLOBAL(JDIMENSION)
+jpeg_write_raw_data (j_compress_ptr cinfo, JSAMPIMAGE data,
+ JDIMENSION num_lines)
+{
+ JDIMENSION lines_per_iMCU_row;
+
+ if (cinfo->global_state != CSTATE_RAW_OK)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ if (cinfo->next_scanline >= cinfo->image_height) {
+ WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
+ return 0;
+ }
+
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->next_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->image_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+
+ /* Give master control module another chance if this is first call to
+ * jpeg_write_raw_data. This lets output of the frame/scan headers be
+ * delayed so that application can write COM, etc, markers between
+ * jpeg_start_compress and jpeg_write_raw_data.
+ */
+ if (cinfo->master->call_pass_startup)
+ (*cinfo->master->pass_startup) (cinfo);
+
+ /* Verify that at least one iMCU row has been passed. */
+ lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->data_unit;
+ if (num_lines < lines_per_iMCU_row)
+ ERREXIT(cinfo, JERR_BUFFER_SIZE);
+
+ /* Directly compress the row. */
+ if (! (*cinfo->codec->compress_data) (cinfo, data)) {
+ /* If compressor did not consume the whole row, suspend processing. */
+ return 0;
+ }
+
+ /* OK, we processed one iMCU row. */
+ cinfo->next_scanline += lines_per_iMCU_row;
+ return lines_per_iMCU_row;
+}
--- /dev/null
+/*
+ * jcarith.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file holds place for arithmetic entropy encoding routines.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Module initialization routine for arithmetic entropy encoding.
+ */
+
+GLOBAL(void)
+jinit_arith_encoder (j_compress_ptr cinfo)
+{
+ ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
+}
--- /dev/null
+/*
+ * jccoefct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the coefficient buffer controller for compression.
+ * This controller is the top level of the JPEG compressor proper.
+ * The coefficient buffer lies between forward-DCT and entropy encoding steps.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+
+
+/* We use a full-image coefficient buffer when doing Huffman optimization,
+ * and also for writing multiple-scan JPEG files. In all cases, the DCT
+ * step is run during the first pass, and subsequent passes need only read
+ * the buffered coefficients.
+ */
+#ifdef ENTROPY_OPT_SUPPORTED
+#define FULL_COEF_BUFFER_SUPPORTED
+#else
+#ifdef C_MULTISCAN_FILES_SUPPORTED
+#define FULL_COEF_BUFFER_SUPPORTED
+#endif
+#endif
+
+
+/* Private buffer controller object */
+
+typedef struct {
+ JDIMENSION iMCU_row_num; /* iMCU row # within image */
+ JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
+ int MCU_vert_offset; /* counts MCU rows within iMCU row */
+ int MCU_rows_per_iMCU_row; /* number of such rows needed */
+
+ /* For single-pass compression, it's sufficient to buffer just one MCU
+ * (although this may prove a bit slow in practice). We allocate a
+ * workspace of C_MAX_DATA_UNITS_IN_MCU coefficient blocks, and reuse it for
+ * each MCU constructed and sent. (On 80x86, the workspace is FAR even
+ * though it's not really very big; this is to keep the module interfaces
+ * unchanged when a large coefficient buffer is necessary.)
+ * In multi-pass modes, this array points to the current MCU's blocks
+ * within the virtual arrays.
+ */
+ JBLOCKROW MCU_buffer[C_MAX_DATA_UNITS_IN_MCU];
+
+ /* In multi-pass modes, we need a virtual block array for each component. */
+ jvirt_barray_ptr whole_image[MAX_COMPONENTS];
+} c_coef_controller;
+
+typedef c_coef_controller * c_coef_ptr;
+
+
+/* Forward declarations */
+METHODDEF(boolean) compress_data
+ JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
+#ifdef FULL_COEF_BUFFER_SUPPORTED
+METHODDEF(boolean) compress_first_pass
+ JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
+METHODDEF(boolean) compress_output
+ JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
+#endif
+
+
+LOCAL(void)
+start_iMCU_row (j_compress_ptr cinfo)
+/* Reset within-iMCU-row counters for a new row */
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+
+ /* In an interleaved scan, an MCU row is the same as an iMCU row.
+ * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
+ * But at the bottom of the image, process only what's left.
+ */
+ if (cinfo->comps_in_scan > 1) {
+ coef->MCU_rows_per_iMCU_row = 1;
+ } else {
+ if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
+ coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
+ else
+ coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
+ }
+
+ coef->mcu_ctr = 0;
+ coef->MCU_vert_offset = 0;
+}
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+
+ coef->iMCU_row_num = 0;
+ start_iMCU_row(cinfo);
+
+ switch (pass_mode) {
+ case JBUF_PASS_THRU:
+ if (coef->whole_image[0] != NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ lossyc->pub.compress_data = compress_data;
+ break;
+#ifdef FULL_COEF_BUFFER_SUPPORTED
+ case JBUF_SAVE_AND_PASS:
+ if (coef->whole_image[0] == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ lossyc->pub.compress_data = compress_first_pass;
+ break;
+ case JBUF_CRANK_DEST:
+ if (coef->whole_image[0] == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ lossyc->pub.compress_data = compress_output;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ break;
+ }
+}
+
+
+/*
+ * Process some data in the single-pass case.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor block rows for each component in the image.
+ * Returns TRUE if the iMCU row is completed, FALSE if suspended.
+ *
+ * NB: input_buf contains a plane for each component in image,
+ * which we index according to the component's SOF position.
+ */
+
+METHODDEF(boolean)
+compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ int blkn, bi, ci, yindex, yoffset, blockcnt;
+ JDIMENSION ypos, xpos;
+ jpeg_component_info *compptr;
+
+ /* Loop to write as much as one whole iMCU row */
+ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
+ yoffset++) {
+ for (MCU_col_num = coef->mcu_ctr; MCU_col_num <= last_MCU_col;
+ MCU_col_num++) {
+ /* Determine where data comes from in input_buf and do the DCT thing.
+ * Each call on forward_DCT processes a horizontal row of DCT blocks
+ * as wide as an MCU; we rely on having allocated the MCU_buffer[] blocks
+ * sequentially. Dummy blocks at the right or bottom edge are filled in
+ * specially. The data in them does not matter for image reconstruction,
+ * so we fill them with values that will encode to the smallest amount of
+ * data, viz: all zeroes in the AC entries, DC entries equal to previous
+ * block's DC value. (Thanks to Thomas Kinsman for this idea.)
+ */
+ blkn = 0;
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
+ : compptr->last_col_width;
+ xpos = MCU_col_num * compptr->MCU_sample_width;
+ ypos = yoffset * DCTSIZE; /* ypos == (yoffset+yindex) * DCTSIZE */
+ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
+ if (coef->iMCU_row_num < last_iMCU_row ||
+ yoffset+yindex < compptr->last_row_height) {
+ (*lossyc->fdct_forward_DCT) (cinfo, compptr,
+ input_buf[compptr->component_index],
+ coef->MCU_buffer[blkn],
+ ypos, xpos, (JDIMENSION) blockcnt);
+ if (blockcnt < compptr->MCU_width) {
+ /* Create some dummy blocks at the right edge of the image. */
+ jzero_far((void FAR *) coef->MCU_buffer[blkn + blockcnt],
+ (compptr->MCU_width - blockcnt) * SIZEOF(JBLOCK));
+ for (bi = blockcnt; bi < compptr->MCU_width; bi++) {
+ coef->MCU_buffer[blkn+bi][0][0] = coef->MCU_buffer[blkn+bi-1][0][0];
+ }
+ }
+ } else {
+ /* Create a row of dummy blocks at the bottom of the image. */
+ jzero_far((void FAR *) coef->MCU_buffer[blkn],
+ compptr->MCU_width * SIZEOF(JBLOCK));
+ for (bi = 0; bi < compptr->MCU_width; bi++) {
+ coef->MCU_buffer[blkn+bi][0][0] = coef->MCU_buffer[blkn-1][0][0];
+ }
+ }
+ blkn += compptr->MCU_width;
+ ypos += DCTSIZE;
+ }
+ }
+ /* Try to write the MCU. In event of a suspension failure, we will
+ * re-DCT the MCU on restart (a bit inefficient, could be fixed...)
+ */
+ if (! (*lossyc->entropy_encode_mcu) (cinfo, coef->MCU_buffer)) {
+ /* Suspension forced; update state counters and exit */
+ coef->MCU_vert_offset = yoffset;
+ coef->mcu_ctr = MCU_col_num;
+ return FALSE;
+ }
+ }
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ coef->mcu_ctr = 0;
+ }
+ /* Completed the iMCU row, advance counters for next one */
+ coef->iMCU_row_num++;
+ start_iMCU_row(cinfo);
+ return TRUE;
+}
+
+
+#ifdef FULL_COEF_BUFFER_SUPPORTED
+
+/*
+ * Process some data in the first pass of a multi-pass case.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor block rows for each component in the image.
+ * This amount of data is read from the source buffer, DCT'd and quantized,
+ * and saved into the virtual arrays. We also generate suitable dummy blocks
+ * as needed at the right and lower edges. (The dummy blocks are constructed
+ * in the virtual arrays, which have been padded appropriately.) This makes
+ * it possible for subsequent passes not to worry about real vs. dummy blocks.
+ *
+ * We must also emit the data to the entropy encoder. This is conveniently
+ * done by calling compress_output() after we've loaded the current strip
+ * of the virtual arrays.
+ *
+ * NB: input_buf contains a plane for each component in image. All
+ * components are DCT'd and loaded into the virtual arrays in this pass.
+ * However, it may be that only a subset of the components are emitted to
+ * the entropy encoder during this first pass; be careful about looking
+ * at the scan-dependent variables (MCU dimensions, etc).
+ */
+
+METHODDEF(boolean)
+compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ JDIMENSION blocks_across, MCUs_across, MCUindex;
+ int bi, ci, h_samp_factor, block_row, block_rows, ndummy;
+ JCOEF lastDC;
+ jpeg_component_info *compptr;
+ JBLOCKARRAY buffer;
+ JBLOCKROW thisblockrow, lastblockrow;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Align the virtual buffer for this component. */
+ buffer = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[ci],
+ coef->iMCU_row_num * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, TRUE);
+ /* Count non-dummy DCT block rows in this iMCU row. */
+ if (coef->iMCU_row_num < last_iMCU_row)
+ block_rows = compptr->v_samp_factor;
+ else {
+ /* NB: can't use last_row_height here, since may not be set! */
+ block_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (block_rows == 0) block_rows = compptr->v_samp_factor;
+ }
+ blocks_across = compptr->width_in_data_units;
+ h_samp_factor = compptr->h_samp_factor;
+ /* Count number of dummy blocks to be added at the right margin. */
+ ndummy = (int) (blocks_across % h_samp_factor);
+ if (ndummy > 0)
+ ndummy = h_samp_factor - ndummy;
+ /* Perform DCT for all non-dummy blocks in this iMCU row. Each call
+ * on forward_DCT processes a complete horizontal row of DCT blocks.
+ */
+ for (block_row = 0; block_row < block_rows; block_row++) {
+ thisblockrow = buffer[block_row];
+ (*lossyc->fdct_forward_DCT) (cinfo, compptr,
+ input_buf[ci], thisblockrow,
+ (JDIMENSION) (block_row * DCTSIZE),
+ (JDIMENSION) 0, blocks_across);
+ if (ndummy > 0) {
+ /* Create dummy blocks at the right edge of the image. */
+ thisblockrow += blocks_across; /* => first dummy block */
+ jzero_far((void FAR *) thisblockrow, ndummy * SIZEOF(JBLOCK));
+ lastDC = thisblockrow[-1][0];
+ for (bi = 0; bi < ndummy; bi++) {
+ thisblockrow[bi][0] = lastDC;
+ }
+ }
+ }
+ /* If at end of image, create dummy block rows as needed.
+ * The tricky part here is that within each MCU, we want the DC values
+ * of the dummy blocks to match the last real block's DC value.
+ * This squeezes a few more bytes out of the resulting file...
+ */
+ if (coef->iMCU_row_num == last_iMCU_row) {
+ blocks_across += ndummy; /* include lower right corner */
+ MCUs_across = blocks_across / h_samp_factor;
+ for (block_row = block_rows; block_row < compptr->v_samp_factor;
+ block_row++) {
+ thisblockrow = buffer[block_row];
+ lastblockrow = buffer[block_row-1];
+ jzero_far((void FAR *) thisblockrow,
+ (size_t) (blocks_across * SIZEOF(JBLOCK)));
+ for (MCUindex = 0; MCUindex < MCUs_across; MCUindex++) {
+ lastDC = lastblockrow[h_samp_factor-1][0];
+ for (bi = 0; bi < h_samp_factor; bi++) {
+ thisblockrow[bi][0] = lastDC;
+ }
+ thisblockrow += h_samp_factor; /* advance to next MCU in row */
+ lastblockrow += h_samp_factor;
+ }
+ }
+ }
+ }
+ /* NB: compress_output will increment iMCU_row_num if successful.
+ * A suspension return will result in redoing all the work above next time.
+ */
+
+ /* Emit data to the entropy encoder, sharing code with subsequent passes */
+ return compress_output(cinfo, input_buf);
+}
+
+
+/*
+ * Process some data in subsequent passes of a multi-pass case.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor block rows for each component in the scan.
+ * The data is obtained from the virtual arrays and fed to the entropy coder.
+ * Returns TRUE if the iMCU row is completed, FALSE if suspended.
+ *
+ * NB: input_buf is ignored; it is likely to be a NULL pointer.
+ */
+
+METHODDEF(boolean)
+compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ int blkn, ci, xindex, yindex, yoffset;
+ JDIMENSION start_col;
+ JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
+ JBLOCKROW buffer_ptr;
+ jpeg_component_info *compptr;
+ (void)input_buf;
+
+ /* Align the virtual buffers for the components used in this scan.
+ * NB: during first pass, this is safe only because the buffers will
+ * already be aligned properly, so jmemmgr.c won't need to do any I/O.
+ */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ buffer[ci] = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
+ coef->iMCU_row_num * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, FALSE);
+ }
+
+ /* Loop to process one whole iMCU row */
+ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
+ yoffset++) {
+ for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
+ MCU_col_num++) {
+ /* Construct list of pointers to DCT blocks belonging to this MCU */
+ blkn = 0; /* index of current DCT block within MCU */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ start_col = MCU_col_num * compptr->MCU_width;
+ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
+ buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
+ for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
+ coef->MCU_buffer[blkn++] = buffer_ptr++;
+ }
+ }
+ }
+ /* Try to write the MCU. */
+ if (! (*lossyc->entropy_encode_mcu) (cinfo, coef->MCU_buffer)) {
+ /* Suspension forced; update state counters and exit */
+ coef->MCU_vert_offset = yoffset;
+ coef->mcu_ctr = MCU_col_num;
+ return FALSE;
+ }
+ }
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ coef->mcu_ctr = 0;
+ }
+ /* Completed the iMCU row, advance counters for next one */
+ coef->iMCU_row_num++;
+ start_iMCU_row(cinfo);
+ return TRUE;
+}
+
+#endif /* FULL_COEF_BUFFER_SUPPORTED */
+
+
+/*
+ * Initialize coefficient buffer controller.
+ */
+
+GLOBAL(void)
+jinit_c_coef_controller (j_compress_ptr cinfo, boolean need_full_buffer)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef;
+
+ coef = (c_coef_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(c_coef_controller));
+ lossyc->coef_private = (struct jpeg_c_coef_controller *) coef;
+ lossyc->coef_start_pass = start_pass_coef;
+
+ /* Create the coefficient buffer. */
+ if (need_full_buffer) {
+#ifdef FULL_COEF_BUFFER_SUPPORTED
+ /* Allocate a full-image virtual array for each component, */
+ /* padded to a multiple of samp_factor DCT blocks in each direction. */
+ int ci;
+ jpeg_component_info *compptr;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) jround_up((long) compptr->height_in_data_units,
+ (long) compptr->v_samp_factor),
+ (JDIMENSION) compptr->v_samp_factor);
+ }
+#else
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif
+ } else {
+ /* We only need a single-MCU buffer. */
+ JBLOCKROW buffer;
+ int i;
+
+ buffer = (JBLOCKROW)
+ (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
+ for (i = 0; i < C_MAX_DATA_UNITS_IN_MCU; i++) {
+ coef->MCU_buffer[i] = buffer + i;
+ }
+ coef->whole_image[0] = NULL; /* flag for no virtual arrays */
+ }
+}
--- /dev/null
+/*
+ * jccolor.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains input colorspace conversion routines.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_color_converter pub; /* public fields */
+
+ /* Private state for RGB->YCC conversion */
+ INT32 * rgb_ycc_tab; /* => table for RGB to YCbCr conversion */
+} my_color_converter;
+
+typedef my_color_converter * my_cconvert_ptr;
+
+
+/**************** RGB -> YCbCr conversion: most common case **************/
+
+/*
+ * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
+ * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
+ * The conversion equations to be implemented are therefore
+ * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
+ * Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE
+ * Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE
+ * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
+ * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
+ * rather than CENTERJSAMPLE, for Cb and Cr. This gave equal positive and
+ * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
+ * were not represented exactly. Now we sacrifice exact representation of
+ * maximum red and maximum blue in order to get exact grayscales.
+ *
+ * To avoid floating-point arithmetic, we represent the fractional constants
+ * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
+ * the products by 2^16, with appropriate rounding, to get the correct answer.
+ *
+ * For even more speed, we avoid doing any multiplications in the inner loop
+ * by precalculating the constants times R,G,B for all possible values.
+ * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
+ * for 12-bit samples it is still acceptable. It's not very reasonable for
+ * 16-bit samples, but if you want lossless storage you shouldn't be changing
+ * colorspace anyway.
+ * The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
+ * in the tables to save adding them separately in the inner loop.
+ */
+
+#define SCALEBITS 16 /* speediest right-shift on some machines */
+#define CBCR_OFFSET ((INT32) CENTERJSAMPLE << SCALEBITS)
+#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
+#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
+
+/* We allocate one big table and divide it up into eight parts, instead of
+ * doing eight alloc_small requests. This lets us use a single table base
+ * address, which can be held in a register in the inner loops on many
+ * machines (more than can hold all eight addresses, anyway).
+ */
+
+#define R_Y_OFF 0 /* offset to R => Y section */
+#define G_Y_OFF (1*(MAXJSAMPLE+1)) /* offset to G => Y section */
+#define B_Y_OFF (2*(MAXJSAMPLE+1)) /* etc. */
+#define R_CB_OFF (3*(MAXJSAMPLE+1))
+#define G_CB_OFF (4*(MAXJSAMPLE+1))
+#define B_CB_OFF (5*(MAXJSAMPLE+1))
+#define R_CR_OFF B_CB_OFF /* B=>Cb, R=>Cr are the same */
+#define G_CR_OFF (6*(MAXJSAMPLE+1))
+#define B_CR_OFF (7*(MAXJSAMPLE+1))
+#define TABLE_SIZE (8*(MAXJSAMPLE+1))
+
+
+/*
+ * Initialize for RGB->YCC colorspace conversion.
+ */
+
+METHODDEF(void)
+rgb_ycc_start (j_compress_ptr cinfo)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ INT32 * rgb_ycc_tab;
+ INT32 i;
+
+ /* Allocate and fill in the conversion tables. */
+ cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (TABLE_SIZE * SIZEOF(INT32)));
+
+ for (i = 0; i <= MAXJSAMPLE; i++) {
+ rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
+ rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
+ rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i + ONE_HALF;
+ rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
+ rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
+ /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
+ * This ensures that the maximum output will round to MAXJSAMPLE
+ * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
+ */
+ rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1;
+/* B=>Cb and R=>Cr tables are the same
+ rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1;
+*/
+ rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
+ rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
+ }
+}
+
+
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ *
+ * Note that we change from the application's interleaved-pixel format
+ * to our internal noninterleaved, one-plane-per-component format.
+ * The input buffer is therefore three times as wide as the output buffer.
+ *
+ * A starting row offset is provided only for the output buffer. The caller
+ * can easily adjust the passed input_buf value to accommodate any row
+ * offset required on that side.
+ */
+
+METHODDEF(void)
+rgb_ycc_convert (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int r, g, b;
+ register INT32 * ctab = cconvert->rgb_ycc_tab;
+ register JSAMPROW inptr;
+ register JSAMPROW outptr0, outptr1, outptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->image_width;
+
+ while (--num_rows >= 0) {
+ inptr = *input_buf++;
+ outptr0 = output_buf[0][output_row];
+ outptr1 = output_buf[1][output_row];
+ outptr2 = output_buf[2][output_row];
+ output_row++;
+ for (col = 0; col < num_cols; col++) {
+ r = GETJSAMPLE(inptr[RGB_RED]);
+ g = GETJSAMPLE(inptr[RGB_GREEN]);
+ b = GETJSAMPLE(inptr[RGB_BLUE]);
+ inptr += RGB_PIXELSIZE;
+ /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
+ * must be too; we do not need an explicit range-limiting operation.
+ * Hence the value being shifted is never negative, and we don't
+ * need the general RIGHT_SHIFT macro.
+ */
+ /* Y */
+ outptr0[col] = (JSAMPLE)
+ ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+ >> SCALEBITS);
+ /* Cb */
+ outptr1[col] = (JSAMPLE)
+ ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
+ >> SCALEBITS);
+ /* Cr */
+ outptr2[col] = (JSAMPLE)
+ ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
+ >> SCALEBITS);
+ }
+ }
+}
+
+
+/**************** Cases other than RGB -> YCbCr **************/
+
+
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles RGB->grayscale conversion, which is the same
+ * as the RGB->Y portion of RGB->YCbCr.
+ * We assume rgb_ycc_start has been called (we only use the Y tables).
+ */
+
+METHODDEF(void)
+rgb_gray_convert (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int r, g, b;
+ register INT32 * ctab = cconvert->rgb_ycc_tab;
+ register JSAMPROW inptr;
+ register JSAMPROW outptr;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->image_width;
+
+ while (--num_rows >= 0) {
+ inptr = *input_buf++;
+ outptr = output_buf[0][output_row];
+ output_row++;
+ for (col = 0; col < num_cols; col++) {
+ r = GETJSAMPLE(inptr[RGB_RED]);
+ g = GETJSAMPLE(inptr[RGB_GREEN]);
+ b = GETJSAMPLE(inptr[RGB_BLUE]);
+ inptr += RGB_PIXELSIZE;
+ /* Y */
+ outptr[col] = (JSAMPLE)
+ ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+ >> SCALEBITS);
+ }
+ }
+}
+
+
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles Adobe-style CMYK->YCCK conversion,
+ * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
+ * conversion as above, while passing K (black) unchanged.
+ * We assume rgb_ycc_start has been called.
+ */
+
+METHODDEF(void)
+cmyk_ycck_convert (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int r, g, b;
+ register INT32 * ctab = cconvert->rgb_ycc_tab;
+ register JSAMPROW inptr;
+ register JSAMPROW outptr0, outptr1, outptr2, outptr3;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->image_width;
+
+ while (--num_rows >= 0) {
+ inptr = *input_buf++;
+ outptr0 = output_buf[0][output_row];
+ outptr1 = output_buf[1][output_row];
+ outptr2 = output_buf[2][output_row];
+ outptr3 = output_buf[3][output_row];
+ output_row++;
+ for (col = 0; col < num_cols; col++) {
+ r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
+ g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
+ b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
+ /* K passes through as-is */
+ outptr3[col] = inptr[3]; /* don't need GETJSAMPLE here */
+ inptr += 4;
+ /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
+ * must be too; we do not need an explicit range-limiting operation.
+ * Hence the value being shifted is never negative, and we don't
+ * need the general RIGHT_SHIFT macro.
+ */
+ /* Y */
+ outptr0[col] = (JSAMPLE)
+ ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+ >> SCALEBITS);
+ /* Cb */
+ outptr1[col] = (JSAMPLE)
+ ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
+ >> SCALEBITS);
+ /* Cr */
+ outptr2[col] = (JSAMPLE)
+ ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
+ >> SCALEBITS);
+ }
+ }
+}
+
+
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles grayscale output with no conversion.
+ * The source can be either plain grayscale or YCbCr (since Y == gray).
+ */
+
+METHODDEF(void)
+grayscale_convert (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows)
+{
+ register JSAMPROW inptr;
+ register JSAMPROW outptr;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->image_width;
+ int instride = cinfo->input_components;
+
+ while (--num_rows >= 0) {
+ inptr = *input_buf++;
+ outptr = output_buf[0][output_row];
+ output_row++;
+ for (col = 0; col < num_cols; col++) {
+ outptr[col] = inptr[0]; /* don't need GETJSAMPLE() here */
+ inptr += instride;
+ }
+ }
+}
+
+
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles multi-component colorspaces without conversion.
+ * We assume input_components == num_components.
+ */
+
+METHODDEF(void)
+null_convert (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows)
+{
+ register JSAMPROW inptr;
+ register JSAMPROW outptr;
+ register JDIMENSION col;
+ register int ci;
+ int nc = cinfo->num_components;
+ JDIMENSION num_cols = cinfo->image_width;
+
+ while (--num_rows >= 0) {
+ /* It seems fastest to make a separate pass for each component. */
+ for (ci = 0; ci < nc; ci++) {
+ inptr = *input_buf;
+ outptr = output_buf[ci][output_row];
+ for (col = 0; col < num_cols; col++) {
+ outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
+ inptr += nc;
+ }
+ }
+ input_buf++;
+ output_row++;
+ }
+}
+
+
+/*
+ * Empty method for start_pass.
+ */
+
+METHODDEF(void)
+null_method (j_compress_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work needed */
+}
+
+
+/*
+ * Module initialization routine for input colorspace conversion.
+ */
+
+GLOBAL(void)
+jinit_color_converter (j_compress_ptr cinfo)
+{
+ my_cconvert_ptr cconvert;
+
+ cconvert = (my_cconvert_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_color_converter));
+ cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
+ /* set start_pass to null method until we find out differently */
+ cconvert->pub.start_pass = null_method;
+
+ /* Make sure input_components agrees with in_color_space */
+ switch (cinfo->in_color_space) {
+ case JCS_GRAYSCALE:
+ if (cinfo->input_components != 1)
+ ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+ break;
+
+ case JCS_RGB:
+#if RGB_PIXELSIZE != 3
+ if (cinfo->input_components != RGB_PIXELSIZE)
+ ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+ break;
+#endif /* else share code with YCbCr */
+
+ case JCS_YCbCr:
+ if (cinfo->input_components != 3)
+ ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+ break;
+
+ case JCS_CMYK:
+ case JCS_YCCK:
+ if (cinfo->input_components != 4)
+ ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+ break;
+
+ default: /* JCS_UNKNOWN can be anything */
+ if (cinfo->input_components < 1)
+ ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+ break;
+ }
+
+ /* Check num_components, set conversion method based on requested space */
+ switch (cinfo->jpeg_color_space) {
+ case JCS_GRAYSCALE:
+ if (cinfo->num_components != 1)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ if (cinfo->in_color_space == JCS_GRAYSCALE)
+ cconvert->pub.color_convert = grayscale_convert;
+ else if (cinfo->in_color_space == JCS_RGB) {
+ cconvert->pub.start_pass = rgb_ycc_start;
+ cconvert->pub.color_convert = rgb_gray_convert;
+ } else if (cinfo->in_color_space == JCS_YCbCr)
+ cconvert->pub.color_convert = grayscale_convert;
+ else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_RGB:
+ if (cinfo->num_components != 3)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ if (cinfo->in_color_space == JCS_RGB && RGB_PIXELSIZE == 3)
+ cconvert->pub.color_convert = null_convert;
+ else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_YCbCr:
+ if (cinfo->num_components != 3)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ if (cinfo->in_color_space == JCS_RGB) {
+ cconvert->pub.start_pass = rgb_ycc_start;
+ cconvert->pub.color_convert = rgb_ycc_convert;
+ } else if (cinfo->in_color_space == JCS_YCbCr)
+ cconvert->pub.color_convert = null_convert;
+ else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_CMYK:
+ if (cinfo->num_components != 4)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ if (cinfo->in_color_space == JCS_CMYK)
+ cconvert->pub.color_convert = null_convert;
+ else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_YCCK:
+ if (cinfo->num_components != 4)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ if (cinfo->in_color_space == JCS_CMYK) {
+ cconvert->pub.start_pass = rgb_ycc_start;
+ cconvert->pub.color_convert = cmyk_ycck_convert;
+ } else if (cinfo->in_color_space == JCS_YCCK)
+ cconvert->pub.color_convert = null_convert;
+ else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ default: /* allow null conversion of JCS_UNKNOWN */
+ if (cinfo->jpeg_color_space != cinfo->in_color_space ||
+ cinfo->num_components != cinfo->input_components)
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ cconvert->pub.color_convert = null_convert;
+ break;
+ }
+}
--- /dev/null
+/*
+ * jcdctmgr.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the forward-DCT management logic.
+ * This code selects a particular DCT implementation to be used,
+ * and it performs related housekeeping chores including coefficient
+ * quantization.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+
+/* Private subobject for this module */
+
+typedef struct {
+ /* Pointer to the DCT routine actually in use */
+ forward_DCT_method_ptr do_dct;
+
+ /* The actual post-DCT divisors --- not identical to the quant table
+ * entries, because of scaling (especially for an unnormalized DCT).
+ * Each table is given in normal array order.
+ */
+ DCTELEM * divisors[NUM_QUANT_TBLS];
+
+#ifdef DCT_FLOAT_SUPPORTED
+ /* Same as above for the floating-point case. */
+ float_DCT_method_ptr do_float_dct;
+ FAST_FLOAT * float_divisors[NUM_QUANT_TBLS];
+#endif
+} fdct_controller;
+
+typedef fdct_controller * fdct_ptr;
+
+
+/*
+ * Initialize for a processing pass.
+ * Verify that all referenced Q-tables are present, and set up
+ * the divisor table for each one.
+ * In the current implementation, DCT of all components is done during
+ * the first pass, even if only some components will be output in the
+ * first scan. Hence all components should be examined here.
+ */
+
+METHODDEF(void)
+start_pass_fdctmgr (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ fdct_ptr fdct = (fdct_ptr) lossyc->fdct_private;
+ int ci, qtblno, i;
+ jpeg_component_info *compptr;
+ JQUANT_TBL * qtbl;
+ DCTELEM * dtbl;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ qtblno = compptr->quant_tbl_no;
+ /* Make sure specified quantization table is present */
+ if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
+ cinfo->quant_tbl_ptrs[qtblno] == NULL)
+ ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
+ qtbl = cinfo->quant_tbl_ptrs[qtblno];
+ /* Compute divisors for this quant table */
+ /* We may do this more than once for same table, but it's not a big deal */
+ switch (cinfo->dct_method) {
+#ifdef DCT_ISLOW_SUPPORTED
+ case JDCT_ISLOW:
+ /* For LL&M IDCT method, divisors are equal to raw quantization
+ * coefficients multiplied by 8 (to counteract scaling).
+ */
+ if (fdct->divisors[qtblno] == NULL) {
+ fdct->divisors[qtblno] = (DCTELEM *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ DCTSIZE2 * SIZEOF(DCTELEM));
+ }
+ dtbl = fdct->divisors[qtblno];
+ for (i = 0; i < DCTSIZE2; i++) {
+ dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3;
+ }
+ break;
+#endif
+#ifdef DCT_IFAST_SUPPORTED
+ case JDCT_IFAST:
+ {
+ /* For AA&N IDCT method, divisors are equal to quantization
+ * coefficients scaled by scalefactor[row]*scalefactor[col], where
+ * scalefactor[0] = 1
+ * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
+ * We apply a further scale factor of 8.
+ */
+#define CONST_BITS 14
+ static const INT16 aanscales[DCTSIZE2] = {
+ /* precomputed values scaled up by 14 bits */
+ 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
+ 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270,
+ 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906,
+ 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315,
+ 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
+ 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552,
+ 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446,
+ 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247
+ };
+ SHIFT_TEMPS
+
+ if (fdct->divisors[qtblno] == NULL) {
+ fdct->divisors[qtblno] = (DCTELEM *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ DCTSIZE2 * SIZEOF(DCTELEM));
+ }
+ dtbl = fdct->divisors[qtblno];
+ for (i = 0; i < DCTSIZE2; i++) {
+ dtbl[i] = (DCTELEM)
+ DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
+ (INT32) aanscales[i]),
+ CONST_BITS-3);
+ }
+ }
+ break;
+#endif
+#ifdef DCT_FLOAT_SUPPORTED
+ case JDCT_FLOAT:
+ {
+ /* For float AA&N IDCT method, divisors are equal to quantization
+ * coefficients scaled by scalefactor[row]*scalefactor[col], where
+ * scalefactor[0] = 1
+ * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
+ * We apply a further scale factor of 8.
+ * What's actually stored is 1/divisor so that the inner loop can
+ * use a multiplication rather than a division.
+ */
+ FAST_FLOAT * fdtbl;
+ int row, col;
+ static const double aanscalefactor[DCTSIZE] = {
+ 1.0, 1.387039845, 1.306562965, 1.175875602,
+ 1.0, 0.785694958, 0.541196100, 0.275899379
+ };
+
+ if (fdct->float_divisors[qtblno] == NULL) {
+ fdct->float_divisors[qtblno] = (FAST_FLOAT *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ DCTSIZE2 * SIZEOF(FAST_FLOAT));
+ }
+ fdtbl = fdct->float_divisors[qtblno];
+ i = 0;
+ for (row = 0; row < DCTSIZE; row++) {
+ for (col = 0; col < DCTSIZE; col++) {
+ fdtbl[i] = (FAST_FLOAT)
+ (1.0 / (((double) qtbl->quantval[i] *
+ aanscalefactor[row] * aanscalefactor[col] * 8.0)));
+ i++;
+ }
+ }
+ }
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+ }
+}
+
+
+/*
+ * Perform forward DCT on one or more blocks of a component.
+ *
+ * The input samples are taken from the sample_data[] array starting at
+ * position start_row/start_col, and moving to the right for any additional
+ * blocks. The quantized coefficients are returned in coef_blocks[].
+ */
+
+METHODDEF(void)
+forward_DCT (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks)
+/* This version is used for integer DCT implementations. */
+{
+ /* This routine is heavily used, so it's worth coding it tightly. */
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ fdct_ptr fdct = (fdct_ptr) lossyc->fdct_private;
+ forward_DCT_method_ptr do_dct = fdct->do_dct;
+ DCTELEM * divisors = fdct->divisors[compptr->quant_tbl_no];
+ DCTELEM workspace[DCTSIZE2]; /* work area for FDCT subroutine */
+ JDIMENSION bi;
+
+ sample_data += start_row; /* fold in the vertical offset once */
+
+ for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) {
+ /* Load data into workspace, applying unsigned->signed conversion */
+ { register DCTELEM *workspaceptr;
+ register JSAMPROW elemptr;
+ register int elemr;
+
+ workspaceptr = workspace;
+ for (elemr = 0; elemr < DCTSIZE; elemr++) {
+ elemptr = sample_data[elemr] + start_col;
+#if DCTSIZE == 8 /* unroll the inner loop */
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+#else
+ { register int elemc;
+ for (elemc = DCTSIZE; elemc > 0; elemc--) {
+ *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
+ }
+ }
+#endif
+ }
+ }
+
+ /* Perform the DCT */
+ (*do_dct) (workspace);
+
+ /* Quantize/descale the coefficients, and store into coef_blocks[] */
+ { register DCTELEM temp, qval;
+ register int i;
+ register JCOEFPTR output_ptr = coef_blocks[bi];
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ qval = divisors[i];
+ temp = workspace[i];
+ /* Divide the coefficient value by qval, ensuring proper rounding.
+ * Since C does not specify the direction of rounding for negative
+ * quotients, we have to force the dividend positive for portability.
+ *
+ * In most files, at least half of the output values will be zero
+ * (at default quantization settings, more like three-quarters...)
+ * so we should ensure that this case is fast. On many machines,
+ * a comparison is enough cheaper than a divide to make a special test
+ * a win. Since both inputs will be nonnegative, we need only test
+ * for a < b to discover whether a/b is 0.
+ * If your machine's division is fast enough, define FAST_DIVIDE.
+ */
+#ifdef FAST_DIVIDE
+#define DIVIDE_BY(a,b) a /= b
+#else
+#define DIVIDE_BY(a,b) if (a >= b) a /= b; else a = 0
+#endif
+ if (temp < 0) {
+ temp = -temp;
+ temp += qval>>1; /* for rounding */
+ DIVIDE_BY(temp, qval);
+ temp = -temp;
+ } else {
+ temp += qval>>1; /* for rounding */
+ DIVIDE_BY(temp, qval);
+ }
+ output_ptr[i] = (JCOEF) temp;
+ }
+ }
+ }
+}
+
+
+#ifdef DCT_FLOAT_SUPPORTED
+
+METHODDEF(void)
+forward_DCT_float (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks)
+/* This version is used for floating-point DCT implementations. */
+{
+ /* This routine is heavily used, so it's worth coding it tightly. */
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ fdct_ptr fdct = (fdct_ptr) lossyc->fdct_private;
+ float_DCT_method_ptr do_dct = fdct->do_float_dct;
+ FAST_FLOAT * divisors = fdct->float_divisors[compptr->quant_tbl_no];
+ FAST_FLOAT workspace[DCTSIZE2]; /* work area for FDCT subroutine */
+ JDIMENSION bi;
+
+ sample_data += start_row; /* fold in the vertical offset once */
+
+ for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) {
+ /* Load data into workspace, applying unsigned->signed conversion */
+ { register FAST_FLOAT *workspaceptr;
+ register JSAMPROW elemptr;
+ register int elemr;
+
+ workspaceptr = workspace;
+ for (elemr = 0; elemr < DCTSIZE; elemr++) {
+ elemptr = sample_data[elemr] + start_col;
+#if DCTSIZE == 8 /* unroll the inner loop */
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+#else
+ { register int elemc;
+ for (elemc = DCTSIZE; elemc > 0; elemc--) {
+ *workspaceptr++ = (FAST_FLOAT)
+ (GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
+ }
+ }
+#endif
+ }
+ }
+
+ /* Perform the DCT */
+ (*do_dct) (workspace);
+
+ /* Quantize/descale the coefficients, and store into coef_blocks[] */
+ { register FAST_FLOAT temp;
+ register int i;
+ register JCOEFPTR output_ptr = coef_blocks[bi];
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ /* Apply the quantization and scaling factor */
+ temp = workspace[i] * divisors[i];
+ /* Round to nearest integer.
+ * Since C does not specify the direction of rounding for negative
+ * quotients, we have to force the dividend positive for portability.
+ * The maximum coefficient size is +-16K (for 12-bit data), so this
+ * code should work for either 16-bit or 32-bit ints.
+ */
+ output_ptr[i] = (JCOEF) ((int) (temp + (FAST_FLOAT) 16384.5) - 16384);
+ }
+ }
+ }
+}
+
+#endif /* DCT_FLOAT_SUPPORTED */
+
+
+/*
+ * Initialize FDCT manager.
+ */
+
+GLOBAL(void)
+jinit_forward_dct (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ fdct_ptr fdct;
+ int i;
+
+ fdct = (fdct_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(fdct_controller));
+ lossyc->fdct_private = (struct jpeg_forward_dct *) fdct;
+ lossyc->fdct_start_pass = start_pass_fdctmgr;
+
+ switch (cinfo->dct_method) {
+#ifdef DCT_ISLOW_SUPPORTED
+ case JDCT_ISLOW:
+ lossyc->fdct_forward_DCT = forward_DCT;
+ fdct->do_dct = jpeg_fdct_islow;
+ break;
+#endif
+#ifdef DCT_IFAST_SUPPORTED
+ case JDCT_IFAST:
+ lossyc->fdct_forward_DCT = forward_DCT;
+ fdct->do_dct = jpeg_fdct_ifast;
+ break;
+#endif
+#ifdef DCT_FLOAT_SUPPORTED
+ case JDCT_FLOAT:
+ lossyc->fdct_forward_DCT = forward_DCT_float;
+ fdct->do_float_dct = jpeg_fdct_float;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+
+ /* Mark divisor tables unallocated */
+ for (i = 0; i < NUM_QUANT_TBLS; i++) {
+ fdct->divisors[i] = NULL;
+#ifdef DCT_FLOAT_SUPPORTED
+ fdct->float_divisors[i] = NULL;
+#endif
+ }
+}
--- /dev/null
+/*
+ * jcdiffct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the difference buffer controller for compression.
+ * This controller is the top level of the lossless JPEG compressor proper.
+ * The difference buffer lies between prediction/differencing and entropy
+ * encoding.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+
+/* We use a full-image sample buffer when doing Huffman optimization,
+ * and also for writing multiple-scan JPEG files. In all cases, the
+ * full-image buffer is filled during the first pass, and the scaling,
+ * prediction and differencing steps are run during subsequent passes.
+ */
+#ifdef ENTROPY_OPT_SUPPORTED
+#define FULL_SAMP_BUFFER_SUPPORTED
+#else
+#ifdef C_MULTISCAN_FILES_SUPPORTED
+#define FULL_SAMP_BUFFER_SUPPORTED
+#endif
+#endif
+
+
+/* Private buffer controller object */
+
+typedef struct {
+ JDIMENSION iMCU_row_num; /* iMCU row # within image */
+ JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
+ int MCU_vert_offset; /* counts MCU rows within iMCU row */
+ int MCU_rows_per_iMCU_row; /* number of such rows needed */
+
+ JSAMPROW cur_row[MAX_COMPONENTS]; /* row of point transformed samples */
+ JSAMPROW prev_row[MAX_COMPONENTS]; /* previous row of Pt'd samples */
+ JDIFFARRAY diff_buf[MAX_COMPONENTS]; /* iMCU row of differences */
+
+ /* In multi-pass modes, we need a virtual sample array for each component. */
+ jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
+} c_diff_controller;
+
+typedef c_diff_controller * c_diff_ptr;
+
+
+/* Forward declarations */
+METHODDEF(boolean) compress_data
+ JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
+#ifdef FULL_SAMP_BUFFER_SUPPORTED
+METHODDEF(boolean) compress_first_pass
+ JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
+METHODDEF(boolean) compress_output
+ JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
+#endif
+
+
+LOCAL(void)
+start_iMCU_row (j_compress_ptr cinfo)
+/* Reset within-iMCU-row counters for a new row */
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_diff_ptr diff = (c_diff_ptr) losslsc->diff_private;
+
+ /* In an interleaved scan, an MCU row is the same as an iMCU row.
+ * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
+ * But at the bottom of the image, process only what's left.
+ */
+ if (cinfo->comps_in_scan > 1) {
+ diff->MCU_rows_per_iMCU_row = 1;
+ } else {
+ if (diff->iMCU_row_num < (cinfo->total_iMCU_rows-1))
+ diff->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
+ else
+ diff->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
+ }
+
+ diff->mcu_ctr = 0;
+ diff->MCU_vert_offset = 0;
+}
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_diff (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_diff_ptr diff = (c_diff_ptr) losslsc->diff_private;
+
+ diff->iMCU_row_num = 0;
+ start_iMCU_row(cinfo);
+
+ switch (pass_mode) {
+ case JBUF_PASS_THRU:
+ if (diff->whole_image[0] != NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ losslsc->pub.compress_data = compress_data;
+ break;
+#ifdef FULL_SAMP_BUFFER_SUPPORTED
+ case JBUF_SAVE_AND_PASS:
+ if (diff->whole_image[0] == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ losslsc->pub.compress_data = compress_first_pass;
+ break;
+ case JBUF_CRANK_DEST:
+ if (diff->whole_image[0] == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ losslsc->pub.compress_data = compress_output;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ break;
+ }
+}
+
+
+#define SWAP_ROWS(rowa,rowb) {JSAMPROW temp; temp=rowa; rowa=rowb; rowb=temp;}
+
+/*
+ * Process some data in the single-pass case.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor rows for each component in the image.
+ * Returns TRUE if the iMCU row is completed, FALSE if suspended.
+ *
+ * NB: input_buf contains a plane for each component in image,
+ * which we index according to the component's SOF position.
+ */
+
+METHODDEF(boolean)
+compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_diff_ptr diff = (c_diff_ptr) losslsc->diff_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ JDIMENSION MCU_count; /* number of MCUs encoded */
+ /* JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; */
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ int comp, ci, yoffset, samp_row, samp_rows, samps_across;
+ jpeg_component_info *compptr;
+
+ /* Loop to write as much as one whole iMCU row */
+ for (yoffset = diff->MCU_vert_offset; yoffset < diff->MCU_rows_per_iMCU_row;
+ yoffset++) {
+
+ MCU_col_num = diff->mcu_ctr;
+
+ /* Scale and predict each scanline of the MCU-row separately.
+ *
+ * Note: We only do this if we are at the start of a MCU-row, ie,
+ * we don't want to reprocess a row suspended by the output.
+ */
+ if (MCU_col_num == 0) {
+ for (comp = 0; comp < cinfo->comps_in_scan; comp++) {
+ compptr = cinfo->cur_comp_info[comp];
+ ci = compptr->component_index;
+ if (diff->iMCU_row_num < last_iMCU_row)
+ samp_rows = compptr->v_samp_factor;
+ else {
+ /* NB: can't use last_row_height here, since may not be set! */
+ samp_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (samp_rows == 0) samp_rows = compptr->v_samp_factor;
+ else {
+ /* Fill dummy difference rows at the bottom edge with zeros, which
+ * will encode to the smallest amount of data.
+ */
+ for (samp_row = samp_rows; samp_row < compptr->v_samp_factor;
+ samp_row++)
+ MEMZERO(diff->diff_buf[ci][samp_row],
+ jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor) * SIZEOF(JDIFF));
+ }
+ }
+ samps_across = compptr->width_in_data_units;
+
+ for (samp_row = 0; samp_row < samp_rows; samp_row++) {
+ (*losslsc->scaler_scale) (cinfo,
+ input_buf[ci][samp_row],
+ diff->cur_row[ci], samps_across);
+ (*losslsc->predict_difference[ci]) (cinfo, ci,
+ diff->cur_row[ci],
+ diff->prev_row[ci],
+ diff->diff_buf[ci][samp_row],
+ samps_across);
+ SWAP_ROWS(diff->cur_row[ci], diff->prev_row[ci]);
+ }
+ }
+ }
+
+ /* Try to write the MCU-row (or remaining portion of suspended MCU-row). */
+ MCU_count =
+ (*losslsc->entropy_encode_mcus) (cinfo,
+ diff->diff_buf, yoffset, MCU_col_num,
+ cinfo->MCUs_per_row - MCU_col_num);
+ if (MCU_count != cinfo->MCUs_per_row - MCU_col_num) {
+ /* Suspension forced; update state counters and exit */
+ diff->MCU_vert_offset = yoffset;
+ diff->mcu_ctr += MCU_col_num;
+ return FALSE;
+ }
+
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ diff->mcu_ctr = 0;
+ }
+
+ /* Completed the iMCU row, advance counters for next one */
+ diff->iMCU_row_num++;
+ start_iMCU_row(cinfo);
+ return TRUE;
+}
+
+
+#ifdef FULL_SAMP_BUFFER_SUPPORTED
+
+/*
+ * Process some data in the first pass of a multi-pass case.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor rows for each component in the image.
+ * This amount of data is read from the source buffer and saved into the
+ * virtual arrays.
+ *
+ * We must also emit the data to the compressor. This is conveniently
+ * done by calling compress_output() after we've loaded the current strip
+ * of the virtual arrays.
+ *
+ * NB: input_buf contains a plane for each component in image. All components
+ * are loaded into the virtual arrays in this pass. However, it may be that
+ * only a subset of the components are emitted to the compressor during
+ * this first pass; be careful about looking at the scan-dependent variables
+ * (MCU dimensions, etc).
+ */
+
+METHODDEF(boolean)
+compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_diff_ptr diff = (c_diff_ptr) losslsc->diff_private;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ JDIMENSION samps_across;
+ int ci, samp_row, samp_rows;
+ JSAMPARRAY buffer[MAX_COMPONENTS];
+ jpeg_component_info *compptr;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Align the virtual buffers for this component. */
+ buffer[ci] = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, diff->whole_image[ci],
+ diff->iMCU_row_num * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, TRUE);
+
+ /* Count non-dummy sample rows in this iMCU row. */
+ if (diff->iMCU_row_num < last_iMCU_row)
+ samp_rows = compptr->v_samp_factor;
+ else {
+ /* NB: can't use last_row_height here, since may not be set! */
+ samp_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (samp_rows == 0) samp_rows = compptr->v_samp_factor;
+ }
+ samps_across = compptr->width_in_data_units;
+
+ /* Perform point transform scaling and prediction/differencing for all
+ * non-dummy rows in this iMCU row. Each call on these functions
+ * process a complete row of samples.
+ */
+ for (samp_row = 0; samp_row < samp_rows; samp_row++) {
+ MEMCOPY(buffer[ci][samp_row], input_buf[ci][samp_row],
+ samps_across * SIZEOF(JSAMPLE));
+ }
+ }
+
+ /* NB: compress_output will increment iMCU_row_num if successful.
+ * A suspension return will result in redoing all the work above next time.
+ */
+
+ /* Emit data to the compressor, sharing code with subsequent passes */
+ return compress_output(cinfo, input_buf);
+}
+
+
+/*
+ * Process some data in subsequent passes of a multi-pass case.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor rows for each component in the scan.
+ * The data is obtained from the virtual arrays and fed to the compressor.
+ * Returns TRUE if the iMCU row is completed, FALSE if suspended.
+ *
+ * NB: input_buf is ignored; it is likely to be a NULL pointer.
+ */
+
+METHODDEF(boolean)
+compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_diff_ptr diff = (c_diff_ptr) losslsc->diff_private;
+ /* JDIMENSION MCU_col_num; */ /* index of current MCU within row */
+ /* JDIMENSION MCU_count; */ /* number of MCUs encoded */
+ int comp, ci /* , yoffset */ ;
+ JSAMPARRAY buffer[MAX_COMPONENTS];
+ jpeg_component_info *compptr;
+ (void)input_buf;
+
+ /* Align the virtual buffers for the components used in this scan.
+ * NB: during first pass, this is safe only because the buffers will
+ * already be aligned properly, so jmemmgr.c won't need to do any I/O.
+ */
+ for (comp = 0; comp < cinfo->comps_in_scan; comp++) {
+ compptr = cinfo->cur_comp_info[comp];
+ ci = compptr->component_index;
+ buffer[ci] = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, diff->whole_image[ci],
+ diff->iMCU_row_num * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, FALSE);
+ }
+
+ return compress_data(cinfo, buffer);
+}
+
+#endif /* FULL_SAMP_BUFFER_SUPPORTED */
+
+
+/*
+ * Initialize difference buffer controller.
+ */
+
+GLOBAL(void)
+jinit_c_diff_controller (j_compress_ptr cinfo, boolean need_full_buffer)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_diff_ptr diff;
+ int ci, row;
+ jpeg_component_info *compptr;
+
+ diff = (c_diff_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(c_diff_controller));
+ losslsc->diff_private = (void *) diff;
+ losslsc->diff_start_pass = start_pass_diff;
+
+ /* Create the prediction row buffers. */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ diff->cur_row[ci] = *(*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) 1);
+ diff->prev_row[ci] = *(*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) 1);
+ }
+
+ /* Create the difference buffer. */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ diff->diff_buf[ci] = (*cinfo->mem->alloc_darray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) compptr->v_samp_factor);
+ /* Prefill difference rows with zeros. We do this because only actual
+ * data is placed in the buffers during prediction/differencing, leaving
+ * any dummy differences at the right edge as zeros, which will encode
+ * to the smallest amount of data.
+ */
+ for (row = 0; row < compptr->v_samp_factor; row++)
+ MEMZERO(diff->diff_buf[ci][row],
+ jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor) * SIZEOF(JDIFF));
+ }
+
+ /* Create the sample buffer. */
+ if (need_full_buffer) {
+#ifdef FULL_SAMP_BUFFER_SUPPORTED
+ /* Allocate a full-image virtual array for each component, */
+ /* padded to a multiple of samp_factor differences in each direction. */
+ int ci;
+ jpeg_component_info *compptr;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ diff->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) jround_up((long) compptr->height_in_data_units,
+ (long) compptr->v_samp_factor),
+ (JDIMENSION) compptr->v_samp_factor);
+ }
+#else
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif
+ } else
+ diff->whole_image[0] = NULL; /* flag for no virtual arrays */
+}
+
+#endif /* C_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jchuff.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy decoding routines which are shared
+ * by the sequential, progressive and lossless decoders.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jchuff.h" /* Declarations shared with jc*huff.c */
+
+
+/*
+ * Compute the derived values for a Huffman table.
+ * This routine also performs some validation checks on the table.
+ */
+
+GLOBAL(void)
+jpeg_make_c_derived_tbl (j_compress_ptr cinfo, boolean isDC, int tblno,
+ c_derived_tbl ** pdtbl)
+{
+ JHUFF_TBL *htbl;
+ c_derived_tbl *dtbl;
+ int p, i, l, lastp, si, maxsymbol;
+ char huffsize[257];
+ unsigned int huffcode[257];
+ unsigned int code;
+
+ /* Note that huffsize[] and huffcode[] are filled in code-length order,
+ * paralleling the order of the symbols themselves in htbl->huffval[].
+ */
+
+ /* Find the input Huffman table */
+ if (tblno < 0 || tblno >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno);
+ htbl =
+ isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno];
+ if (htbl == NULL)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno);
+
+ /* Allocate a workspace if we haven't already done so. */
+ if (*pdtbl == NULL)
+ *pdtbl = (c_derived_tbl *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(c_derived_tbl));
+ dtbl = *pdtbl;
+
+ /* Figure C.1: make table of Huffman code length for each symbol */
+
+ p = 0;
+ for (l = 1; l <= 16; l++) {
+ i = (int) htbl->bits[l];
+ if (i < 0 || p + i > 256) /* protect against table overrun */
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+ while (i--)
+ huffsize[p++] = (char) l;
+ }
+ huffsize[p] = 0;
+ lastp = p;
+
+ /* Figure C.2: generate the codes themselves */
+ /* We also validate that the counts represent a legal Huffman code tree. */
+
+ code = 0;
+ si = huffsize[0];
+ p = 0;
+ while (huffsize[p]) {
+ while (((int) huffsize[p]) == si) {
+ huffcode[p++] = code;
+ code++;
+ }
+ /* code is now 1 more than the last code used for codelength si; but
+ * it must still fit in si bits, since no code is allowed to be all ones.
+ * BUG FIX 2001-09-03: Comparison must be >, not >=
+ */
+ if (((INT32) code) > (((INT32) 1) << si))
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+ code <<= 1;
+ si++;
+ }
+
+ /* Figure C.3: generate encoding tables */
+ /* These are code and size indexed by symbol value */
+
+ /* Set all codeless symbols to have code length 0;
+ * this lets us detect duplicate VAL entries here, and later
+ * allows emit_bits to detect any attempt to emit such symbols.
+ */
+ MEMZERO(dtbl->ehufsi, SIZEOF(dtbl->ehufsi));
+
+ /* This is also a convenient place to check for out-of-range
+ * and duplicated VAL entries. We allow 0..255 for AC symbols
+ * but only 0..16 for DC. (We could constrain them further
+ * based on data depth and mode, but this seems enough.)
+ */
+ maxsymbol = isDC ? 16 : 255;
+
+ for (p = 0; p < lastp; p++) {
+ i = htbl->huffval[p];
+ if (i < 0 || i > maxsymbol || dtbl->ehufsi[i])
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+ dtbl->ehufco[i] = huffcode[p];
+ dtbl->ehufsi[i] = huffsize[p];
+ }
+}
+
+
+/*
+ * Generate the best Huffman code table for the given counts, fill htbl.
+ *
+ * The JPEG standard requires that no symbol be assigned a codeword of all
+ * one bits (so that padding bits added at the end of a compressed segment
+ * can't look like a valid code). Because of the canonical ordering of
+ * codewords, this just means that there must be an unused slot in the
+ * longest codeword length category. Section K.2 of the JPEG spec suggests
+ * reserving such a slot by pretending that symbol 256 is a valid symbol
+ * with count 1. In theory that's not optimal; giving it count zero but
+ * including it in the symbol set anyway should give a better Huffman code.
+ * But the theoretically better code actually seems to come out worse in
+ * practice, because it produces more all-ones bytes (which incur stuffed
+ * zero bytes in the final file). In any case the difference is tiny.
+ *
+ * The JPEG standard requires Huffman codes to be no more than 16 bits long.
+ * If some symbols have a very small but nonzero probability, the Huffman tree
+ * must be adjusted to meet the code length restriction. We currently use
+ * the adjustment method suggested in JPEG section K.2. This method is *not*
+ * optimal; it may not choose the best possible limited-length code. But
+ * typically only very-low-frequency symbols will be given less-than-optimal
+ * lengths, so the code is almost optimal. Experimental comparisons against
+ * an optimal limited-length-code algorithm indicate that the difference is
+ * microscopic --- usually less than a hundredth of a percent of total size.
+ * So the extra complexity of an optimal algorithm doesn't seem worthwhile.
+ */
+
+GLOBAL(void)
+jpeg_gen_optimal_table (j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])
+{
+#define MAX_CLEN 32 /* assumed maximum initial code length */
+ UINT8 bits[MAX_CLEN+1]; /* bits[k] = # of symbols with code length k */
+ int codesize[257]; /* codesize[k] = code length of symbol k */
+ int others[257]; /* next symbol in current branch of tree */
+ int c1, c2;
+ int p, i, j;
+ long v;
+
+ /* This algorithm is explained in section K.2 of the JPEG standard */
+
+ MEMZERO(bits, SIZEOF(bits));
+ MEMZERO(codesize, SIZEOF(codesize));
+ for (i = 0; i < 257; i++)
+ others[i] = -1; /* init links to empty */
+
+ freq[256] = 1; /* make sure 256 has a nonzero count */
+ /* Including the pseudo-symbol 256 in the Huffman procedure guarantees
+ * that no real symbol is given code-value of all ones, because 256
+ * will be placed last in the largest codeword category.
+ */
+
+ /* Huffman's basic algorithm to assign optimal code lengths to symbols */
+
+ for (;;) {
+ /* Find the smallest nonzero frequency, set c1 = its symbol */
+ /* In case of ties, take the larger symbol number */
+ c1 = -1;
+ v = 1000000000L;
+ for (i = 0; i <= 256; i++) {
+ if (freq[i] && freq[i] <= v) {
+ v = freq[i];
+ c1 = i;
+ }
+ }
+
+ /* Find the next smallest nonzero frequency, set c2 = its symbol */
+ /* In case of ties, take the larger symbol number */
+ c2 = -1;
+ v = 1000000000L;
+ for (i = 0; i <= 256; i++) {
+ if (freq[i] && freq[i] <= v && i != c1) {
+ v = freq[i];
+ c2 = i;
+ }
+ }
+
+ /* Done if we've merged everything into one frequency */
+ if (c2 < 0)
+ break;
+
+ /* Else merge the two counts/trees */
+ freq[c1] += freq[c2];
+ freq[c2] = 0;
+
+ /* Increment the codesize of everything in c1's tree branch */
+ codesize[c1]++;
+ while (others[c1] >= 0) {
+ c1 = others[c1];
+ codesize[c1]++;
+ }
+
+ others[c1] = c2; /* chain c2 onto c1's tree branch */
+
+ /* Increment the codesize of everything in c2's tree branch */
+ codesize[c2]++;
+ while (others[c2] >= 0) {
+ c2 = others[c2];
+ codesize[c2]++;
+ }
+ }
+
+ /* Now count the number of symbols of each code length */
+ for (i = 0; i <= 256; i++) {
+ if (codesize[i]) {
+ /* The JPEG standard seems to think that this can't happen, */
+ /* but I'm paranoid... */
+ if (codesize[i] > MAX_CLEN)
+ ERREXIT(cinfo, JERR_HUFF_CLEN_OVERFLOW);
+
+ bits[codesize[i]]++;
+ }
+ }
+
+ /* JPEG doesn't allow symbols with code lengths over 16 bits, so if the pure
+ * Huffman procedure assigned any such lengths, we must adjust the coding.
+ * Here is what the JPEG spec says about how this next bit works:
+ * Since symbols are paired for the longest Huffman code, the symbols are
+ * removed from this length category two at a time. The prefix for the pair
+ * (which is one bit shorter) is allocated to one of the pair; then,
+ * skipping the BITS entry for that prefix length, a code word from the next
+ * shortest nonzero BITS entry is converted into a prefix for two code words
+ * one bit longer.
+ */
+
+ for (i = MAX_CLEN; i > 16; i--) {
+ while (bits[i] > 0) {
+ j = i - 2; /* find length of new prefix to be used */
+ while (bits[j] == 0)
+ j--;
+
+ bits[i] -= 2; /* remove two symbols */
+ bits[i-1]++; /* one goes in this length */
+ bits[j+1] += 2; /* two new symbols in this length */
+ bits[j]--; /* symbol of this length is now a prefix */
+ }
+ }
+
+ /* Remove the count for the pseudo-symbol 256 from the largest codelength */
+ while (bits[i] == 0) /* find largest codelength still in use */
+ i--;
+ bits[i]--;
+
+ /* Return final symbol counts (only for lengths 0..16) */
+ MEMCOPY(htbl->bits, bits, SIZEOF(htbl->bits));
+
+ /* Return a list of the symbols sorted by code length */
+ /* It's not real clear to me why we don't need to consider the codelength
+ * changes made above, but the JPEG spec seems to think this works.
+ */
+ p = 0;
+ for (i = 1; i <= MAX_CLEN; i++) {
+ for (j = 0; j <= 255; j++) {
+ if (codesize[j] == i) {
+ htbl->huffval[p] = (UINT8) j;
+ p++;
+ }
+ }
+ }
+
+ /* Set sent_table FALSE so updated table will be written to JPEG file. */
+ htbl->sent_table = FALSE;
+}
--- /dev/null
+/*
+ * jchuff.h
+ *
+ * Copyright (C) 1991-1997, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains declarations for Huffman entropy encoding routines
+ * that are shared between the sequential encoder (jchuff.c) and the
+ * progressive encoder (jcphuff.c). No other modules need to see these.
+ */
+
+/* The legal range of a DCT coefficient is
+ * -1024 .. +1023 for 8-bit data;
+ * -16384 .. +16383 for 12-bit data.
+ * Hence the magnitude should always fit in 10 or 14 bits respectively.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define MAX_COEF_BITS 10
+#else
+#define MAX_COEF_BITS 14
+#endif
+
+/* The legal range of a spatial difference is
+ * -32767 .. +32768.
+ * Hence the magnitude should always fit in 16 bits.
+ */
+
+#define MAX_DIFF_BITS 16
+
+/* Derived data constructed for each Huffman table */
+
+typedef struct {
+ unsigned int ehufco[256]; /* code for each symbol */
+ char ehufsi[256]; /* length of code for each symbol */
+ /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */
+} c_derived_tbl;
+
+/* Short forms of external names for systems with brain-damaged linkers. */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_make_c_derived_tbl jMkCDerived
+#define jpeg_gen_optimal_table jGenOptTbl
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+/* Expand a Huffman table definition into the derived format */
+EXTERN(void) jpeg_make_c_derived_tbl
+ JPP((j_compress_ptr cinfo, boolean isDC, int tblno,
+ c_derived_tbl ** pdtbl));
+
+/* Generate an optimal table definition given the specified counts */
+EXTERN(void) jpeg_gen_optimal_table
+ JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[]));
--- /dev/null
+/*
+ * jcinit.c
+ *
+ * Copyright (C) 1991-1997, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains initialization logic for the JPEG compressor.
+ * This routine is in charge of selecting the modules to be executed and
+ * making an initialization call to each one.
+ *
+ * Logically, this code belongs in jcmaster.c. It's split out because
+ * linking this routine implies linking the entire compression library.
+ * For a transcoding-only application, we want to be able to use jcmaster.c
+ * without linking in the whole library.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Master selection of compression modules.
+ * This is done once at the start of processing an image. We determine
+ * which modules will be used and give them appropriate initialization calls.
+ */
+
+GLOBAL(void)
+jinit_compress_master (j_compress_ptr cinfo)
+{
+ /* Initialize master control (includes parameter checking/processing) */
+ jinit_c_master_control(cinfo, FALSE /* full compression */);
+
+ /* Initialize compression codec */
+ jinit_c_codec(cinfo);
+
+ /* Preprocessing */
+ if (! cinfo->raw_data_in) {
+ jinit_color_converter(cinfo);
+ jinit_downsampler(cinfo);
+ jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
+ }
+
+ jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
+
+ jinit_marker_writer(cinfo);
+
+ /* We can now tell the memory manager to allocate virtual arrays. */
+ (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
+
+ /* Write the datastream header (SOI) immediately.
+ * Frame and scan headers are postponed till later.
+ * This lets application insert special markers after the SOI.
+ */
+ (*cinfo->marker->write_file_header) (cinfo);
+}
--- /dev/null
+/*
+ * jclhuff.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy encoding routines for lossless JPEG.
+ *
+ * Much of the complexity here has to do with supporting output suspension.
+ * If the data destination module demands suspension, we want to be able to
+ * back up to the start of the current MCU. To do this, we copy state
+ * variables into local working storage, and update them back to the
+ * permanent JPEG objects only upon successful completion of an MCU.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+#include "jchuff.h" /* Declarations shared with jc*huff.c */
+
+
+/* Expanded entropy encoder object for Huffman encoding.
+ *
+ * The savable_state subrecord contains fields that change within an MCU,
+ * but must not be updated permanently until we complete the MCU.
+ */
+
+typedef struct {
+ INT32 put_buffer; /* current bit-accumulation buffer */
+ int put_bits; /* # of bits now in it */
+} savable_state;
+
+/* This macro is to work around compilers with missing or broken
+ * structure assignment. You'll need to fix this code if you have
+ * such a compiler and you change MAX_COMPS_IN_SCAN.
+ */
+
+#ifndef NO_STRUCT_ASSIGN
+#define ASSIGN_STATE(dest,src) ((dest) = (src))
+#else
+#define ASSIGN_STATE(dest,src) \
+ ((dest).put_buffer = (src).put_buffer, \
+ (dest).put_bits = (src).put_bits)
+#endif
+
+
+typedef struct {
+ int ci, yoffset, MCU_width;
+} lhe_input_ptr_info;
+
+
+typedef struct {
+ savable_state saved; /* Bit buffer at start of MCU */
+
+ /* These fields are NOT loaded into local working state. */
+ unsigned int restarts_to_go; /* MCUs left in this restart interval */
+ int next_restart_num; /* next restart number to write (0-7) */
+
+ /* Pointers to derived tables (these workspaces have image lifespan) */
+ c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
+
+ /* Pointers to derived tables to be used for each data unit within an MCU */
+ c_derived_tbl * cur_tbls[C_MAX_DATA_UNITS_IN_MCU];
+
+#ifdef ENTROPY_OPT_SUPPORTED /* Statistics tables for optimization */
+ long * count_ptrs[NUM_HUFF_TBLS];
+
+ /* Pointers to stats tables to be used for each data unit within an MCU */
+ long * cur_counts[C_MAX_DATA_UNITS_IN_MCU];
+#endif
+
+ /* Pointers to the proper input difference row for each group of data units
+ * within an MCU. For each component, there are Vi groups of Hi data units.
+ */
+ JDIFFROW input_ptr[C_MAX_DATA_UNITS_IN_MCU];
+
+ /* Number of input pointers in use for the current MCU. This is the sum
+ * of all Vi in the MCU.
+ */
+ int num_input_ptrs;
+
+ /* Information used for positioning the input pointers within the input
+ * difference rows.
+ */
+ lhe_input_ptr_info input_ptr_info[C_MAX_DATA_UNITS_IN_MCU];
+
+ /* Index of the proper input pointer for each data unit within an MCU */
+ int input_ptr_index[C_MAX_DATA_UNITS_IN_MCU];
+
+} lhuff_entropy_encoder;
+
+typedef lhuff_entropy_encoder * lhuff_entropy_ptr;
+
+/* Working state while writing an MCU.
+ * This struct contains all the fields that are needed by subroutines.
+ */
+
+typedef struct {
+ JOCTET * next_output_byte; /* => next byte to write in buffer */
+ size_t free_in_buffer; /* # of byte spaces remaining in buffer */
+ savable_state cur; /* Current bit buffer & DC state */
+ j_compress_ptr cinfo; /* dump_buffer needs access to this */
+} working_state;
+
+
+/* Forward declarations */
+METHODDEF(JDIMENSION) encode_mcus_huff (j_compress_ptr cinfo,
+ JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num,
+ JDIMENSION MCU_col_num,
+ JDIMENSION nMCU);
+METHODDEF(void) finish_pass_huff JPP((j_compress_ptr cinfo));
+#ifdef ENTROPY_OPT_SUPPORTED
+METHODDEF(JDIMENSION) encode_mcus_gather (j_compress_ptr cinfo,
+ JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num,
+ JDIMENSION MCU_col_num,
+ JDIMENSION nMCU);
+METHODDEF(void) finish_pass_gather JPP((j_compress_ptr cinfo));
+#endif
+
+
+/*
+ * Initialize for a Huffman-compressed scan.
+ * If gather_statistics is TRUE, we do not output anything during the scan,
+ * just count the Huffman symbols used and generate Huffman code tables.
+ */
+
+METHODDEF(void)
+start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsc->entropy_private;
+ int ci, dctbl, sampn, ptrn, yoffset, xoffset;
+ jpeg_component_info * compptr;
+
+ if (gather_statistics) {
+#ifdef ENTROPY_OPT_SUPPORTED
+ losslsc->entropy_encode_mcus = encode_mcus_gather;
+ losslsc->pub.entropy_finish_pass = finish_pass_gather;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ losslsc->entropy_encode_mcus = encode_mcus_huff;
+ losslsc->pub.entropy_finish_pass = finish_pass_huff;
+ }
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ dctbl = compptr->dc_tbl_no;
+ if (gather_statistics) {
+#ifdef ENTROPY_OPT_SUPPORTED
+ /* Check for invalid table indexes */
+ /* (make_c_derived_tbl does this in the other path) */
+ if (dctbl < 0 || dctbl >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, dctbl);
+ /* Allocate and zero the statistics tables */
+ /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
+ if (entropy->count_ptrs[dctbl] == NULL)
+ entropy->count_ptrs[dctbl] = (long *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ 257 * SIZEOF(long));
+ MEMZERO(entropy->count_ptrs[dctbl], 257 * SIZEOF(long));
+#endif
+ } else {
+ /* Compute derived values for Huffman tables */
+ /* We may do this more than once for a table, but it's not expensive */
+ jpeg_make_c_derived_tbl(cinfo, TRUE, dctbl,
+ & entropy->derived_tbls[dctbl]);
+ }
+ }
+
+ /* Precalculate encoding info for each sample in an MCU of this scan */
+ for (sampn = 0, ptrn = 0; sampn < cinfo->data_units_in_MCU;) {
+ compptr = cinfo->cur_comp_info[cinfo->MCU_membership[sampn]];
+ ci = compptr->component_index;
+ /* ci = cinfo->MCU_membership[sampn];
+ compptr = cinfo->cur_comp_info[ci];*/
+ for (yoffset = 0; yoffset < compptr->MCU_height; yoffset++, ptrn++) {
+ /* Precalculate the setup info for each input pointer */
+ entropy->input_ptr_info[ptrn].ci = ci;
+ entropy->input_ptr_info[ptrn].yoffset = yoffset;
+ entropy->input_ptr_info[ptrn].MCU_width = compptr->MCU_width;
+ for (xoffset = 0; xoffset < compptr->MCU_width; xoffset++, sampn++) {
+ /* Precalculate the input pointer index for each sample */
+ entropy->input_ptr_index[sampn] = ptrn;
+ /* Precalculate which tables to use for each sample */
+ entropy->cur_tbls[sampn] = entropy->derived_tbls[compptr->dc_tbl_no];
+ entropy->cur_counts[sampn] = entropy->count_ptrs[compptr->dc_tbl_no];
+ }
+ }
+ }
+ entropy->num_input_ptrs = ptrn;
+
+ /* Initialize bit buffer to empty */
+ entropy->saved.put_buffer = 0;
+ entropy->saved.put_bits = 0;
+
+ /* Initialize restart stuff */
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num = 0;
+}
+
+
+/* Outputting bytes to the file */
+
+/* Emit a byte, taking 'action' if must suspend. */
+#define emit_byte(state,val,action) \
+ { *(state)->next_output_byte++ = (JOCTET) (val); \
+ if (--(state)->free_in_buffer == 0) \
+ if (! dump_buffer(state)) \
+ { action; } }
+
+
+LOCAL(boolean)
+dump_buffer (working_state * state)
+/* Empty the output buffer; return TRUE if successful, FALSE if must suspend */
+{
+ struct jpeg_destination_mgr * dest = state->cinfo->dest;
+
+ if (! (*dest->empty_output_buffer) (state->cinfo))
+ return FALSE;
+ /* After a successful buffer dump, must reset buffer pointers */
+ state->next_output_byte = dest->next_output_byte;
+ state->free_in_buffer = dest->free_in_buffer;
+ return TRUE;
+}
+
+
+/* Outputting bits to the file */
+
+/* Only the right 24 bits of put_buffer are used; the valid bits are
+ * left-justified in this part. At most 16 bits can be passed to emit_bits
+ * in one call, and we never retain more than 7 bits in put_buffer
+ * between calls, so 24 bits are sufficient.
+ */
+
+INLINE
+LOCAL(boolean)
+emit_bits (working_state * state, unsigned int code, int size)
+/* Emit some bits; return TRUE if successful, FALSE if must suspend */
+{
+ /* This routine is heavily used, so it's worth coding tightly. */
+ register INT32 put_buffer = (INT32) code;
+ register int put_bits = state->cur.put_bits;
+
+ /* if size is 0, caller used an invalid Huffman table entry */
+ if (size == 0)
+ ERREXIT(state->cinfo, JERR_HUFF_MISSING_CODE);
+
+ put_buffer &= (((INT32) 1)<<size) - 1; /* mask off any extra bits in code */
+
+ put_bits += size; /* new number of bits in buffer */
+
+ put_buffer <<= 24 - put_bits; /* align incoming bits */
+
+ put_buffer |= state->cur.put_buffer; /* and merge with old buffer contents */
+
+ while (put_bits >= 8) {
+ int c = (int) ((put_buffer >> 16) & 0xFF);
+
+ emit_byte(state, c, return FALSE);
+ if (c == 0xFF) { /* need to stuff a zero byte? */
+ emit_byte(state, 0, return FALSE);
+ }
+ put_buffer <<= 8;
+ put_bits -= 8;
+ }
+
+ state->cur.put_buffer = put_buffer; /* update state variables */
+ state->cur.put_bits = put_bits;
+
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+flush_bits (working_state * state)
+{
+ if (! emit_bits(state, 0x7F, 7)) /* fill any partial byte with ones */
+ return FALSE;
+ state->cur.put_buffer = 0; /* and reset bit-buffer to empty */
+ state->cur.put_bits = 0;
+ return TRUE;
+}
+
+
+/*
+ * Emit a restart marker & resynchronize predictions.
+ */
+
+LOCAL(boolean)
+emit_restart (working_state * state, int restart_num)
+{
+ /* int ci; */
+
+ if (! flush_bits(state))
+ return FALSE;
+
+ emit_byte(state, 0xFF, return FALSE);
+ emit_byte(state, JPEG_RST0 + restart_num, return FALSE);
+
+ /* The restart counter is not updated until we successfully write the MCU. */
+
+ return TRUE;
+}
+
+
+/*
+ * Encode and output one nMCU's worth of Huffman-compressed differences.
+ */
+
+METHODDEF(JDIMENSION)
+encode_mcus_huff (j_compress_ptr cinfo, JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num, JDIMENSION MCU_col_num,
+ JDIMENSION nMCU)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsc->entropy_private;
+ working_state state;
+ unsigned int mcu_num;
+ int sampn, ci, yoffset, MCU_width, ptrn;
+ /* jpeg_component_info * compptr; */
+
+ /* Load up working state */
+ state.next_output_byte = cinfo->dest->next_output_byte;
+ state.free_in_buffer = cinfo->dest->free_in_buffer;
+ ASSIGN_STATE(state.cur, entropy->saved);
+ state.cinfo = cinfo;
+
+ /* Emit restart marker if needed */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! emit_restart(&state, entropy->next_restart_num))
+ return 0;
+ }
+
+ /* Set input pointer locations based on MCU_col_num */
+ for (ptrn = 0; ptrn < entropy->num_input_ptrs; ptrn++) {
+ ci = entropy->input_ptr_info[ptrn].ci;
+ yoffset = entropy->input_ptr_info[ptrn].yoffset;
+ MCU_width = entropy->input_ptr_info[ptrn].MCU_width;
+ entropy->input_ptr[ptrn] =
+ diff_buf[ci][MCU_row_num + yoffset] + (MCU_col_num * MCU_width);
+ }
+
+ for (mcu_num = 0; mcu_num < nMCU; mcu_num++) {
+
+ /* Inner loop handles the samples in the MCU */
+ for (sampn = 0; sampn < cinfo->data_units_in_MCU; sampn++) {
+ register int temp, temp2 /* , temp3 */ ;
+ register int nbits;
+ c_derived_tbl *dctbl = entropy->cur_tbls[sampn];
+
+ /* Encode the difference per section H.1.2.2 */
+
+ /* Input the sample difference */
+ temp = *entropy->input_ptr[entropy->input_ptr_index[sampn]]++;
+
+ if (temp & 0x8000) { /* instead of temp < 0 */
+ temp = (-temp) & 0x7FFF; /* absolute value, mod 2^16 */
+ if (temp == 0) /* special case: magnitude = 32768 */
+ temp2 = temp = 0x8000;
+ temp2 = ~ temp; /* one's complement of magnitude */
+ } else {
+ temp &= 0x7FFF; /* abs value mod 2^16 */
+ temp2 = temp; /* magnitude */
+ }
+
+ /* Find the number of bits needed for the magnitude of the difference */
+ nbits = 0;
+ while (temp) {
+ nbits++;
+ temp >>= 1;
+ }
+ /* Check for out-of-range difference values.
+ */
+ if (nbits > MAX_DIFF_BITS)
+ ERREXIT(cinfo, JERR_BAD_DIFF);
+
+ /* Emit the Huffman-coded symbol for the number of bits */
+ if (! emit_bits(&state, dctbl->ehufco[nbits], dctbl->ehufsi[nbits]))
+ return mcu_num;
+
+ /* Emit that number of bits of the value, if positive, */
+ /* or the complement of its magnitude, if negative. */
+ if (nbits && /* emit_bits rejects calls with size 0 */
+ nbits != 16) /* special case: no bits should be emitted */
+ if (! emit_bits(&state, (unsigned int) temp2, nbits))
+ return mcu_num;
+ }
+
+ /* Completed MCU, so update state */
+ cinfo->dest->next_output_byte = state.next_output_byte;
+ cinfo->dest->free_in_buffer = state.free_in_buffer;
+ ASSIGN_STATE(entropy->saved, state.cur);
+
+ /* Update restart-interval state too */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num++;
+ entropy->next_restart_num &= 7;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ }
+
+ return nMCU;
+}
+
+
+/*
+ * Finish up at the end of a Huffman-compressed scan.
+ */
+
+METHODDEF(void)
+finish_pass_huff (j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsc->entropy_private;
+ working_state state;
+
+ /* Load up working state ... flush_bits needs it */
+ state.next_output_byte = cinfo->dest->next_output_byte;
+ state.free_in_buffer = cinfo->dest->free_in_buffer;
+ ASSIGN_STATE(state.cur, entropy->saved);
+ state.cinfo = cinfo;
+
+ /* Flush out the last data */
+ if (! flush_bits(&state))
+ ERREXIT(cinfo, JERR_CANT_SUSPEND);
+
+ /* Update state */
+ cinfo->dest->next_output_byte = state.next_output_byte;
+ cinfo->dest->free_in_buffer = state.free_in_buffer;
+ ASSIGN_STATE(entropy->saved, state.cur);
+}
+
+
+/*
+ * Huffman coding optimization.
+ *
+ * We first scan the supplied data and count the number of uses of each symbol
+ * that is to be Huffman-coded. (This process MUST agree with the code above.)
+ * Then we build a Huffman coding tree for the observed counts.
+ * Symbols which are not needed at all for the particular image are not
+ * assigned any code, which saves space in the DHT marker as well as in
+ * the compressed data.
+ */
+
+#ifdef ENTROPY_OPT_SUPPORTED
+
+/*
+ * Trial-encode one nMCU's worth of Huffman-compressed differences.
+ * No data is actually output, so no suspension return is possible.
+ */
+
+METHODDEF(JDIMENSION)
+encode_mcus_gather (j_compress_ptr cinfo, JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num, JDIMENSION MCU_col_num,
+ JDIMENSION nMCU)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsc->entropy_private;
+ unsigned int mcu_num;
+ int sampn, ci, yoffset, MCU_width, ptrn;
+ /* jpeg_component_info * compptr; */
+
+ /* Take care of restart intervals if needed */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ /* Update restart state */
+ entropy->restarts_to_go = cinfo->restart_interval;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ /* Set input pointer locations based on MCU_col_num */
+ for (ptrn = 0; ptrn < entropy->num_input_ptrs; ptrn++) {
+ ci = entropy->input_ptr_info[ptrn].ci;
+ yoffset = entropy->input_ptr_info[ptrn].yoffset;
+ MCU_width = entropy->input_ptr_info[ptrn].MCU_width;
+ entropy->input_ptr[ptrn] =
+ diff_buf[ci][MCU_row_num + yoffset] + (MCU_col_num * MCU_width);
+ }
+
+ for (mcu_num = 0; mcu_num < nMCU; mcu_num++) {
+
+ /* Inner loop handles the samples in the MCU */
+ for (sampn = 0; sampn < cinfo->data_units_in_MCU; sampn++) {
+ register int temp;
+ register int nbits;
+ /* c_derived_tbl *dctbl = entropy->cur_tbls[sampn]; */
+ long * counts = entropy->cur_counts[sampn];
+
+ /* Encode the difference per section H.1.2.2 */
+
+ /* Input the sample difference */
+ temp = *entropy->input_ptr[entropy->input_ptr_index[sampn]]++;
+
+ if (temp & 0x8000) { /* instead of temp < 0 */
+ temp = (-temp) & 0x7FFF; /* absolute value, mod 2^16 */
+ if (temp == 0) /* special case: magnitude = 32768 */
+ temp = 0x8000;
+ } else
+ temp &= 0x7FFF; /* abs value mod 2^16 */
+
+ /* Find the number of bits needed for the magnitude of the difference */
+ nbits = 0;
+ while (temp) {
+ nbits++;
+ temp >>= 1;
+ }
+ /* Check for out-of-range difference values.
+ */
+ if (nbits > MAX_DIFF_BITS)
+ ERREXIT(cinfo, JERR_BAD_DIFF);
+
+ /* Count the Huffman symbol for the number of bits */
+ counts[nbits]++;
+ }
+ }
+
+ return nMCU;
+}
+
+
+/*
+ * Finish up a statistics-gathering pass and create the new Huffman tables.
+ */
+
+METHODDEF(void)
+finish_pass_gather (j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsc->entropy_private;
+ int ci, dctbl;
+ jpeg_component_info * compptr;
+ JHUFF_TBL **htblptr;
+ boolean did_dc[NUM_HUFF_TBLS];
+
+ /* It's important not to apply jpeg_gen_optimal_table more than once
+ * per table, because it clobbers the input frequency counts!
+ */
+ MEMZERO(did_dc, SIZEOF(did_dc));
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ dctbl = compptr->dc_tbl_no;
+ if (! did_dc[dctbl]) {
+ htblptr = & cinfo->dc_huff_tbl_ptrs[dctbl];
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+ jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[dctbl]);
+ did_dc[dctbl] = TRUE;
+ }
+ }
+}
+
+
+#endif /* ENTROPY_OPT_SUPPORTED */
+
+
+METHODDEF(boolean)
+need_optimization_pass (j_compress_ptr cinfo)
+{
+ (void)cinfo;
+ return TRUE;
+}
+
+
+/*
+ * Module initialization routine for Huffman entropy encoding.
+ */
+
+GLOBAL(void)
+jinit_lhuff_encoder (j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy;
+ int i;
+
+ entropy = (lhuff_entropy_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(lhuff_entropy_encoder));
+ losslsc->entropy_private = (struct jpeg_entropy_encoder *) entropy;
+ losslsc->pub.entropy_start_pass = start_pass_huff;
+ losslsc->pub.need_optimization_pass = need_optimization_pass;
+
+ /* Mark tables unallocated */
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ entropy->derived_tbls[i] = NULL;
+#ifdef ENTROPY_OPT_SUPPORTED
+ entropy->count_ptrs[i] = NULL;
+#endif
+ }
+}
--- /dev/null
+/*
+ * jclossls.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the control logic for the lossless JPEG compressor.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h"
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+
+ (*losslsc->scaler_start_pass) (cinfo);
+ (*losslsc->predict_start_pass) (cinfo);
+ (*losslsc->diff_start_pass) (cinfo, pass_mode);
+}
+
+
+/*
+ * Initialize the lossless compression codec.
+ * This is called only once, during master selection.
+ */
+
+GLOBAL(void)
+jinit_lossless_c_codec(j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc;
+
+ /* Create subobject in permanent pool */
+ losslsc = (j_lossless_c_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(jpeg_lossless_c_codec));
+ cinfo->codec = (struct jpeg_c_codec *) losslsc;
+
+ /* Initialize sub-modules */
+
+ /* Scaler */
+ jinit_c_scaler(cinfo);
+
+ /* Differencer */
+ jinit_differencer(cinfo);
+
+ /* Entropy encoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+ jinit_arith_encoder(cinfo);
+ } else {
+ jinit_lhuff_encoder(cinfo);
+ }
+
+ /* Need a full-image difference buffer in any multi-pass mode. */
+ jinit_c_diff_controller(cinfo,
+ (boolean) (cinfo->num_scans > 1 ||
+ cinfo->optimize_coding));
+
+ /* Initialize method pointers.
+ *
+ * Note: entropy_start_pass and entropy_finish_pass are assigned in
+ * jclhuff.c and compress_data is assigned in jcdiffct.c.
+ */
+ losslsc->pub.start_pass = start_pass;
+}
+
+#endif /* C_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jclossy.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the control logic for the lossy JPEG compressor.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h"
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+
+ (*lossyc->fdct_start_pass) (cinfo);
+ (*lossyc->coef_start_pass) (cinfo, pass_mode);
+}
+
+
+/*
+ * Initialize the lossy compression codec.
+ * This is called only once, during master selection.
+ */
+
+GLOBAL(void)
+jinit_lossy_c_codec (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc;
+
+ /* Create subobject in permanent pool */
+ lossyc = (j_lossy_c_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(jpeg_lossy_c_codec));
+ cinfo->codec = (struct jpeg_c_codec *) lossyc;
+
+ /* Initialize sub-modules */
+
+ /* Forward DCT */
+ jinit_forward_dct(cinfo);
+ /* Entropy encoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+ jinit_arith_encoder(cinfo);
+ } else {
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+#ifdef C_PROGRESSIVE_SUPPORTED
+ jinit_phuff_encoder(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else
+ jinit_shuff_encoder(cinfo);
+ }
+
+ /* Need a full-image coefficient buffer in any multi-pass mode. */
+ jinit_c_coef_controller(cinfo,
+ (boolean) (cinfo->num_scans > 1 ||
+ cinfo->optimize_coding));
+
+ /* Initialize method pointers.
+ *
+ * Note: entropy_start_pass and entropy_finish_pass are assigned in
+ * jcshuff.c or jcphuff.c and compress_data is assigned in jccoefct.c.
+ */
+ lossyc->pub.start_pass = start_pass;
+}
--- /dev/null
+/*
+ * jcmainct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the main buffer controller for compression.
+ * The main buffer lies between the pre-processor and the JPEG
+ * compressor proper; it holds downsampled data in the JPEG colorspace.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Note: currently, there is no operating mode in which a full-image buffer
+ * is needed at this step. If there were, that mode could not be used with
+ * "raw data" input, since this module is bypassed in that case. However,
+ * we've left the code here for possible use in special applications.
+ */
+#undef FULL_MAIN_BUFFER_SUPPORTED
+
+
+/* Private buffer controller object */
+
+typedef struct {
+ struct jpeg_c_main_controller pub; /* public fields */
+
+ JDIMENSION cur_iMCU_row; /* number of current iMCU row */
+ JDIMENSION rowgroup_ctr; /* counts row groups received in iMCU row */
+ boolean suspended; /* remember if we suspended output */
+ J_BUF_MODE pass_mode; /* current operating mode */
+
+ /* If using just a strip buffer, this points to the entire set of buffers
+ * (we allocate one for each component). In the full-image case, this
+ * points to the currently accessible strips of the virtual arrays.
+ */
+ JSAMPARRAY buffer[MAX_COMPONENTS];
+
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ /* If using full-image storage, this array holds pointers to virtual-array
+ * control blocks for each component. Unused if not full-image storage.
+ */
+ jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
+#endif
+} my_main_controller;
+
+typedef my_main_controller * my_main_ptr;
+
+
+/* Forward declarations */
+METHODDEF(void) process_data_simple_main
+ JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
+ JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+METHODDEF(void) process_data_buffer_main
+ JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
+ JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
+#endif
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+
+ /* Do nothing in raw-data mode. */
+ if (cinfo->raw_data_in)
+ return;
+
+ mainPtr->cur_iMCU_row = 0; /* initialize counters */
+ mainPtr->rowgroup_ctr = 0;
+ mainPtr->suspended = FALSE;
+ mainPtr->pass_mode = pass_mode; /* save mode for use by process_data */
+
+ switch (pass_mode) {
+ case JBUF_PASS_THRU:
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ if (mainPtr->whole_image[0] != NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif
+ mainPtr->pub.process_data = process_data_simple_main;
+ break;
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ case JBUF_SAVE_SOURCE:
+ case JBUF_CRANK_DEST:
+ case JBUF_SAVE_AND_PASS:
+ if (mainPtr->whole_image[0] == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ mainPtr->pub.process_data = process_data_buffer_main;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ break;
+ }
+}
+
+
+/*
+ * Process some data.
+ * This routine handles the simple pass-through mode,
+ * where we have only a strip buffer.
+ */
+
+METHODDEF(void)
+process_data_simple_main (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail)
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+ JDIMENSION data_unit = (JDIMENSION)(cinfo->data_unit);
+
+ while (mainPtr->cur_iMCU_row < cinfo->total_iMCU_rows) {
+ /* Read input data if we haven't filled the main buffer yet */
+ if (mainPtr->rowgroup_ctr < data_unit)
+ (*cinfo->prep->pre_process_data) (cinfo,
+ input_buf, in_row_ctr, in_rows_avail,
+ mainPtr->buffer, &mainPtr->rowgroup_ctr,
+ (JDIMENSION) data_unit);
+
+ /* If we don't have a full iMCU row buffered, return to application for
+ * more data. Note that preprocessor will always pad to fill the iMCU row
+ * at the bottom of the image.
+ */
+ if (mainPtr->rowgroup_ctr != data_unit)
+ return;
+
+ /* Send the completed row to the compressor */
+ if (! (*cinfo->codec->compress_data) (cinfo, mainPtr->buffer)) {
+ /* If compressor did not consume the whole row, then we must need to
+ * suspend processing and return to the application. In this situation
+ * we pretend we didn't yet consume the last input row; otherwise, if
+ * it happened to be the last row of the image, the application would
+ * think we were done.
+ */
+ if (! mainPtr->suspended) {
+ (*in_row_ctr)--;
+ mainPtr->suspended = TRUE;
+ }
+ return;
+ }
+ /* We did finish the row. Undo our little suspension hack if a previous
+ * call suspended; then mark the main buffer empty.
+ */
+ if (mainPtr->suspended) {
+ (*in_row_ctr)++;
+ mainPtr->suspended = FALSE;
+ }
+ mainPtr->rowgroup_ctr = 0;
+ mainPtr->cur_iMCU_row++;
+ }
+}
+
+
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+
+/*
+ * Process some data.
+ * This routine handles all of the modes that use a full-size buffer.
+ */
+
+METHODDEF(void)
+process_data_buffer_main (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail)
+{
+ my_main_ptr main = (my_main_ptr) cinfo->main;
+ int ci;
+ jpeg_component_info *compptr;
+ boolean writing = (mainPtr->pass_mode != JBUF_CRANK_DEST);
+ JDIMENSION data_unit = (JDIMENSION)(cinfo->data_unit);
+
+ while (mainPtr->cur_iMCU_row < cinfo->total_iMCU_rows) {
+ /* Realign the virtual buffers if at the start of an iMCU row. */
+ if (mainPtr->rowgroup_ctr == 0) {
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ mainPtr->buffer[ci] = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, mainPtr->whole_image[ci],
+ mainPtr->cur_iMCU_row * (compptr->v_samp_factor * data_unit),
+ (JDIMENSION) (compptr->v_samp_factor * data_unit), writing);
+ }
+ /* In a read pass, pretend we just read some source data. */
+ if (! writing) {
+ *in_row_ctr += cinfo->max_v_samp_factor * data_unit;
+ mainPtr->rowgroup_ctr = data_unit;
+ }
+ }
+
+ /* If a write pass, read input data until the current iMCU row is full. */
+ /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
+ if (writing) {
+ (*cinfo->prep->pre_process_data) (cinfo,
+ input_buf, in_row_ctr, in_rows_avail,
+ mainPtr->buffer, &mainPtr->rowgroup_ctr,
+ (JDIMENSION) data_unit);
+ /* Return to application if we need more data to fill the iMCU row. */
+ if (mainPtr->rowgroup_ctr < data_unit)
+ return;
+ }
+
+ /* Emit data, unless this is a sink-only pass. */
+ if (mainPtr->pass_mode != JBUF_SAVE_SOURCE) {
+ if (! (*cinfo->codec->compress_data) (cinfo, mainPtr->buffer)) {
+ /* If compressor did not consume the whole row, then we must need to
+ * suspend processing and return to the application. In this situation
+ * we pretend we didn't yet consume the last input row; otherwise, if
+ * it happened to be the last row of the image, the application would
+ * think we were done.
+ */
+ if (! mainPtr->suspended) {
+ (*in_row_ctr)--;
+ mainPtr->suspended = TRUE;
+ }
+ return;
+ }
+ /* We did finish the row. Undo our little suspension hack if a previous
+ * call suspended; then mark the main buffer empty.
+ */
+ if (mainPtr->suspended) {
+ (*in_row_ctr)++;
+ mainPtr->suspended = FALSE;
+ }
+ }
+
+ /* If get here, we are done with this iMCU row. Mark buffer empty. */
+ mainPtr->rowgroup_ctr = 0;
+ mainPtr->cur_iMCU_row++;
+ }
+}
+
+#endif /* FULL_MAIN_BUFFER_SUPPORTED */
+
+
+/*
+ * Initialize main buffer controller.
+ */
+
+GLOBAL(void)
+jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
+{
+ my_main_ptr mainPtr;
+ int ci;
+ jpeg_component_info *compptr;
+ int data_unit = cinfo->data_unit;
+
+ mainPtr = (my_main_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_main_controller));
+ cinfo->main = (struct jpeg_c_main_controller *) mainPtr;
+ mainPtr->pub.start_pass = start_pass_main;
+
+ /* We don't need to create a buffer in raw-data mode. */
+ if (cinfo->raw_data_in)
+ return;
+
+ /* Create the buffer. It holds downsampled data, so each component
+ * may be of a different size.
+ */
+ if (need_full_buffer) {
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ /* Allocate a full-image virtual array for each component */
+ /* Note we pad the bottom to a multiple of the iMCU height */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ mainPtr->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
+ compptr->width_in_data_units * data_unit,
+ (JDIMENSION) jround_up((long) compptr->height_in_data_units,
+ (long) compptr->v_samp_factor) * data_unit,
+ (JDIMENSION) (compptr->v_samp_factor * data_unit));
+ }
+#else
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif
+ } else {
+#ifdef FULL_MAIN_BUFFER_SUPPORTED
+ mainPtr->whole_image[0] = NULL; /* flag for no virtual arrays */
+#endif
+ /* Allocate a strip buffer for each component */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ mainPtr->buffer[ci] = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ compptr->width_in_data_units * data_unit,
+ (JDIMENSION) (compptr->v_samp_factor * data_unit));
+ }
+ }
+}
--- /dev/null
+/*
+ * jcmarker.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains routines to write JPEG datastream markers.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+typedef enum { /* JPEG marker codes */
+ M_SOF0 = 0xc0,
+ M_SOF1 = 0xc1,
+ M_SOF2 = 0xc2,
+ M_SOF3 = 0xc3,
+
+ M_SOF5 = 0xc5,
+ M_SOF6 = 0xc6,
+ M_SOF7 = 0xc7,
+
+ M_JPG = 0xc8,
+ M_SOF9 = 0xc9,
+ M_SOF10 = 0xca,
+ M_SOF11 = 0xcb,
+
+ M_SOF13 = 0xcd,
+ M_SOF14 = 0xce,
+ M_SOF15 = 0xcf,
+
+ M_DHT = 0xc4,
+
+ M_DAC = 0xcc,
+
+ M_RST0 = 0xd0,
+ M_RST1 = 0xd1,
+ M_RST2 = 0xd2,
+ M_RST3 = 0xd3,
+ M_RST4 = 0xd4,
+ M_RST5 = 0xd5,
+ M_RST6 = 0xd6,
+ M_RST7 = 0xd7,
+
+ M_SOI = 0xd8,
+ M_EOI = 0xd9,
+ M_SOS = 0xda,
+ M_DQT = 0xdb,
+ M_DNL = 0xdc,
+ M_DRI = 0xdd,
+ M_DHP = 0xde,
+ M_EXP = 0xdf,
+
+ M_APP0 = 0xe0,
+ M_APP1 = 0xe1,
+ M_APP2 = 0xe2,
+ M_APP3 = 0xe3,
+ M_APP4 = 0xe4,
+ M_APP5 = 0xe5,
+ M_APP6 = 0xe6,
+ M_APP7 = 0xe7,
+ M_APP8 = 0xe8,
+ M_APP9 = 0xe9,
+ M_APP10 = 0xea,
+ M_APP11 = 0xeb,
+ M_APP12 = 0xec,
+ M_APP13 = 0xed,
+ M_APP14 = 0xee,
+ M_APP15 = 0xef,
+
+ M_JPG0 = 0xf0,
+ M_JPG13 = 0xfd,
+ M_COM = 0xfe,
+
+ M_TEM = 0x01,
+
+ M_ERROR = 0x100
+} JPEG_MARKER;
+
+
+/* Private state */
+
+typedef struct {
+ struct jpeg_marker_writer pub; /* public fields */
+
+ unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
+} my_marker_writer;
+
+typedef my_marker_writer * my_marker_ptr;
+
+
+/*
+ * Basic output routines.
+ *
+ * Note that we do not support suspension while writing a marker.
+ * Therefore, an application using suspension must ensure that there is
+ * enough buffer space for the initial markers (typ. 600-700 bytes) before
+ * calling jpeg_start_compress, and enough space to write the trailing EOI
+ * (a few bytes) before calling jpeg_finish_compress. Multipass compression
+ * modes are not supported at all with suspension, so those two are the only
+ * points where markers will be written.
+ */
+
+LOCAL(void)
+emit_byte (j_compress_ptr cinfo, int val)
+/* Emit a byte */
+{
+ struct jpeg_destination_mgr * dest = cinfo->dest;
+
+ *(dest->next_output_byte)++ = (JOCTET) val;
+ if (--dest->free_in_buffer == 0) {
+ if (! (*dest->empty_output_buffer) (cinfo))
+ ERREXIT(cinfo, JERR_CANT_SUSPEND);
+ }
+}
+
+
+LOCAL(void)
+emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
+/* Emit a marker code */
+{
+ emit_byte(cinfo, 0xFF);
+ emit_byte(cinfo, (int) mark);
+}
+
+
+LOCAL(void)
+emit_2bytes (j_compress_ptr cinfo, int value)
+/* Emit a 2-byte integer; these are always MSB first in JPEG files */
+{
+ emit_byte(cinfo, (value >> 8) & 0xFF);
+ emit_byte(cinfo, value & 0xFF);
+}
+
+
+/*
+ * Routines to write specific marker types.
+ */
+
+LOCAL(int)
+emit_dqt (j_compress_ptr cinfo, int index)
+/* Emit a DQT marker */
+/* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
+{
+ JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
+ int prec;
+ int i;
+
+ if (qtbl == NULL)
+ ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
+
+ prec = 0;
+ for (i = 0; i < DCTSIZE2; i++) {
+ if (qtbl->quantval[i] > 255)
+ prec = 1;
+ }
+
+ if (! qtbl->sent_table) {
+ emit_marker(cinfo, M_DQT);
+
+ emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);
+
+ emit_byte(cinfo, index + (prec<<4));
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ /* The table entries must be emitted in zigzag order. */
+ unsigned int qval = qtbl->quantval[jpeg_natural_order[i]];
+ if (prec)
+ emit_byte(cinfo, (int) (qval >> 8));
+ emit_byte(cinfo, (int) (qval & 0xFF));
+ }
+
+ qtbl->sent_table = TRUE;
+ }
+
+ return prec;
+}
+
+
+LOCAL(void)
+emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
+/* Emit a DHT marker */
+{
+ JHUFF_TBL * htbl;
+ int length, i;
+
+ if (is_ac) {
+ htbl = cinfo->ac_huff_tbl_ptrs[index];
+ index += 0x10; /* output index has AC bit set */
+ } else {
+ htbl = cinfo->dc_huff_tbl_ptrs[index];
+ }
+
+ if (htbl == NULL)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
+
+ if (! htbl->sent_table) {
+ emit_marker(cinfo, M_DHT);
+
+ length = 0;
+ for (i = 1; i <= 16; i++)
+ length += htbl->bits[i];
+
+ emit_2bytes(cinfo, length + 2 + 1 + 16);
+ emit_byte(cinfo, index);
+
+ for (i = 1; i <= 16; i++)
+ emit_byte(cinfo, htbl->bits[i]);
+
+ for (i = 0; i < length; i++)
+ emit_byte(cinfo, htbl->huffval[i]);
+
+ htbl->sent_table = TRUE;
+ }
+}
+
+
+LOCAL(void)
+emit_dac (j_compress_ptr cinfo)
+/* Emit a DAC marker */
+/* Since the useful info is so small, we want to emit all the tables in */
+/* one DAC marker. Therefore this routine does its own scan of the table. */
+{
+#ifdef C_ARITH_CODING_SUPPORTED
+ char dc_in_use[NUM_ARITH_TBLS];
+ char ac_in_use[NUM_ARITH_TBLS];
+ int length, i;
+ jpeg_component_info *compptr;
+
+ for (i = 0; i < NUM_ARITH_TBLS; i++)
+ dc_in_use[i] = ac_in_use[i] = 0;
+
+ for (i = 0; i < cinfo->comps_in_scan; i++) {
+ compptr = cinfo->cur_comp_info[i];
+ dc_in_use[compptr->dc_tbl_no] = 1;
+ ac_in_use[compptr->ac_tbl_no] = 1;
+ }
+
+ length = 0;
+ for (i = 0; i < NUM_ARITH_TBLS; i++)
+ length += dc_in_use[i] + ac_in_use[i];
+
+ emit_marker(cinfo, M_DAC);
+
+ emit_2bytes(cinfo, length*2 + 2);
+
+ for (i = 0; i < NUM_ARITH_TBLS; i++) {
+ if (dc_in_use[i]) {
+ emit_byte(cinfo, i);
+ emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
+ }
+ if (ac_in_use[i]) {
+ emit_byte(cinfo, i + 0x10);
+ emit_byte(cinfo, cinfo->arith_ac_K[i]);
+ }
+ }
+#else
+ (void)cinfo;
+#endif /* C_ARITH_CODING_SUPPORTED */
+}
+
+
+LOCAL(void)
+emit_dri (j_compress_ptr cinfo)
+/* Emit a DRI marker */
+{
+ emit_marker(cinfo, M_DRI);
+
+ emit_2bytes(cinfo, 4); /* fixed length */
+
+ emit_2bytes(cinfo, (int) cinfo->restart_interval);
+}
+
+
+LOCAL(void)
+emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
+/* Emit a SOF marker */
+{
+ int ci;
+ jpeg_component_info *compptr;
+
+ emit_marker(cinfo, code);
+
+ emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
+
+ /* Make sure image isn't bigger than SOF field can handle */
+ if ((long) cinfo->image_height > 65535L ||
+ (long) cinfo->image_width > 65535L)
+ ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
+
+ emit_byte(cinfo, cinfo->data_precision);
+ emit_2bytes(cinfo, (int) cinfo->image_height);
+ emit_2bytes(cinfo, (int) cinfo->image_width);
+
+ emit_byte(cinfo, cinfo->num_components);
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ emit_byte(cinfo, compptr->component_id);
+ emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
+ emit_byte(cinfo, compptr->quant_tbl_no);
+ }
+}
+
+
+LOCAL(void)
+emit_sos (j_compress_ptr cinfo)
+/* Emit a SOS marker */
+{
+ int i, td, ta;
+ jpeg_component_info *compptr;
+
+ emit_marker(cinfo, M_SOS);
+
+ emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
+
+ emit_byte(cinfo, cinfo->comps_in_scan);
+
+ for (i = 0; i < cinfo->comps_in_scan; i++) {
+ compptr = cinfo->cur_comp_info[i];
+ emit_byte(cinfo, compptr->component_id);
+ td = compptr->dc_tbl_no;
+ ta = compptr->ac_tbl_no;
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+ /* Progressive mode: only DC or only AC tables are used in one scan;
+ * furthermore, Huffman coding of DC refinement uses no table at all.
+ * We emit 0 for unused field(s); this is recommended by the P&M text
+ * but does not seem to be specified in the standard.
+ */
+ if (cinfo->Ss == 0) {
+ ta = 0; /* DC scan */
+ if (cinfo->Ah != 0 && !cinfo->arith_code)
+ td = 0; /* no DC table either */
+ } else {
+ td = 0; /* AC scan */
+ }
+ }
+ emit_byte(cinfo, (td << 4) + ta);
+ }
+
+ emit_byte(cinfo, cinfo->Ss);
+ emit_byte(cinfo, cinfo->Se);
+ emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
+}
+
+
+LOCAL(void)
+emit_jfif_app0 (j_compress_ptr cinfo)
+/* Emit a JFIF-compliant APP0 marker */
+{
+ /*
+ * Length of APP0 block (2 bytes)
+ * Block ID (4 bytes - ASCII "JFIF")
+ * Zero byte (1 byte to terminate the ID string)
+ * Version Major, Minor (2 bytes - major first)
+ * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
+ * Xdpu (2 bytes - dots per unit horizontal)
+ * Ydpu (2 bytes - dots per unit vertical)
+ * Thumbnail X size (1 byte)
+ * Thumbnail Y size (1 byte)
+ */
+
+ emit_marker(cinfo, M_APP0);
+
+ emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
+
+ emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */
+ emit_byte(cinfo, 0x46);
+ emit_byte(cinfo, 0x49);
+ emit_byte(cinfo, 0x46);
+ emit_byte(cinfo, 0);
+ emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */
+ emit_byte(cinfo, cinfo->JFIF_minor_version);
+ emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
+ emit_2bytes(cinfo, (int) cinfo->X_density);
+ emit_2bytes(cinfo, (int) cinfo->Y_density);
+ emit_byte(cinfo, 0); /* No thumbnail image */
+ emit_byte(cinfo, 0);
+}
+
+
+LOCAL(void)
+emit_adobe_app14 (j_compress_ptr cinfo)
+/* Emit an Adobe APP14 marker */
+{
+ /*
+ * Length of APP14 block (2 bytes)
+ * Block ID (5 bytes - ASCII "Adobe")
+ * Version Number (2 bytes - currently 100)
+ * Flags0 (2 bytes - currently 0)
+ * Flags1 (2 bytes - currently 0)
+ * Color transform (1 byte)
+ *
+ * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
+ * now in circulation seem to use Version = 100, so that's what we write.
+ *
+ * We write the color transform byte as 1 if the JPEG color space is
+ * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with
+ * whether the encoder performed a transformation, which is pretty useless.
+ */
+
+ emit_marker(cinfo, M_APP14);
+
+ emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
+
+ emit_byte(cinfo, 0x41); /* Identifier: ASCII "Adobe" */
+ emit_byte(cinfo, 0x64);
+ emit_byte(cinfo, 0x6F);
+ emit_byte(cinfo, 0x62);
+ emit_byte(cinfo, 0x65);
+ emit_2bytes(cinfo, 100); /* Version */
+ emit_2bytes(cinfo, 0); /* Flags0 */
+ emit_2bytes(cinfo, 0); /* Flags1 */
+ switch (cinfo->jpeg_color_space) {
+ case JCS_YCbCr:
+ emit_byte(cinfo, 1); /* Color transform = 1 */
+ break;
+ case JCS_YCCK:
+ emit_byte(cinfo, 2); /* Color transform = 2 */
+ break;
+ default:
+ emit_byte(cinfo, 0); /* Color transform = 0 */
+ break;
+ }
+}
+
+
+/*
+ * These routines allow writing an arbitrary marker with parameters.
+ * The only intended use is to emit COM or APPn markers after calling
+ * write_file_header and before calling write_frame_header.
+ * Other uses are not guaranteed to produce desirable results.
+ * Counting the parameter bytes properly is the caller's responsibility.
+ */
+
+METHODDEF(void)
+write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
+/* Emit an arbitrary marker header */
+{
+ if (datalen > (unsigned int) 65533) /* safety check */
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ emit_marker(cinfo, (JPEG_MARKER) marker);
+
+ emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */
+}
+
+METHODDEF(void)
+write_marker_byte (j_compress_ptr cinfo, int val)
+/* Emit one byte of marker parameters following write_marker_header */
+{
+ emit_byte(cinfo, val);
+}
+
+
+/*
+ * Write datastream header.
+ * This consists of an SOI and optional APPn markers.
+ * We recommend use of the JFIF marker, but not the Adobe marker,
+ * when using YCbCr or grayscale data. The JFIF marker should NOT
+ * be used for any other JPEG colorspace. The Adobe marker is helpful
+ * to distinguish RGB, CMYK, and YCCK colorspaces.
+ * Note that an application can write additional header markers after
+ * jpeg_start_compress returns.
+ */
+
+METHODDEF(void)
+write_file_header (j_compress_ptr cinfo)
+{
+ my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
+
+ emit_marker(cinfo, M_SOI); /* first the SOI */
+
+ /* SOI is defined to reset restart interval to 0 */
+ marker->last_restart_interval = 0;
+
+ if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */
+ emit_jfif_app0(cinfo);
+ if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
+ emit_adobe_app14(cinfo);
+}
+
+
+/*
+ * Write frame header.
+ * This consists of DQT and SOFn markers.
+ * Note that we do not emit the SOF until we have emitted the DQT(s).
+ * This avoids compatibility problems with incorrect implementations that
+ * try to error-check the quant table numbers as soon as they see the SOF.
+ */
+
+METHODDEF(void)
+write_frame_header (j_compress_ptr cinfo)
+{
+ int ci, prec;
+ boolean is_baseline;
+ jpeg_component_info *compptr;
+
+ prec = 0;
+ if (cinfo->process != JPROC_LOSSLESS) {
+ /* Emit DQT for each quantization table.
+ * Note that emit_dqt() suppresses any duplicate tables.
+ */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ prec += emit_dqt(cinfo, compptr->quant_tbl_no);
+ }
+ /* now prec is nonzero iff there are any 16-bit quant tables. */
+ }
+
+ /* Check for a non-baseline specification.
+ * Note we assume that Huffman table numbers won't be changed later.
+ */
+ if (cinfo->arith_code || cinfo->process != JPROC_SEQUENTIAL ||
+ cinfo->data_precision != 8) {
+ is_baseline = FALSE;
+ } else {
+ is_baseline = TRUE;
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
+ is_baseline = FALSE;
+ }
+ if (prec && is_baseline) {
+ is_baseline = FALSE;
+ /* If it's baseline except for quantizer size, warn the user */
+ TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
+ }
+ }
+
+ /* Emit the proper SOF marker */
+ if (cinfo->arith_code) {
+ if (cinfo->process == JPROC_PROGRESSIVE)
+ emit_sof(cinfo, M_SOF10); /* SOF code for progressive arithmetic */
+ else if (cinfo->process == JPROC_LOSSLESS)
+ emit_sof(cinfo, M_SOF11); /* SOF code for lossless arithmetic */
+ else
+ emit_sof(cinfo, M_SOF9); /* SOF code for sequential arithmetic */
+ } else {
+ if (cinfo->process == JPROC_PROGRESSIVE)
+ emit_sof(cinfo, M_SOF2); /* SOF code for progressive Huffman */
+ else if (cinfo->process == JPROC_LOSSLESS)
+ emit_sof(cinfo, M_SOF3); /* SOF code for lossless Huffman */
+ else if (is_baseline)
+ emit_sof(cinfo, M_SOF0); /* SOF code for baseline implementation */
+ else
+ emit_sof(cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */
+ }
+}
+
+
+/*
+ * Write scan header.
+ * This consists of DHT or DAC markers, optional DRI, and SOS.
+ * Compressed data will be written following the SOS.
+ */
+
+METHODDEF(void)
+write_scan_header (j_compress_ptr cinfo)
+{
+ my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
+ int i;
+ jpeg_component_info *compptr;
+
+ if (cinfo->arith_code) {
+ /* Emit arith conditioning info. We may have some duplication
+ * if the file has multiple scans, but it's so small it's hardly
+ * worth worrying about.
+ */
+ emit_dac(cinfo);
+ } else {
+ /* Emit Huffman tables.
+ * Note that emit_dht() suppresses any duplicate tables.
+ */
+ for (i = 0; i < cinfo->comps_in_scan; i++) {
+ compptr = cinfo->cur_comp_info[i];
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+ /* Progressive mode: only DC or only AC tables are used in one scan */
+ if (cinfo->Ss == 0) {
+ if (cinfo->Ah == 0) /* DC needs no table for refinement scan */
+ emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
+ } else {
+ emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
+ }
+ } else if (cinfo->process == JPROC_LOSSLESS) {
+ /* Lossless mode: only DC tables are used */
+ emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
+ } else {
+ /* Sequential mode: need both DC and AC tables */
+ emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
+ emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
+ }
+ }
+ }
+
+ /* Emit DRI if required --- note that DRI value could change for each scan.
+ * We avoid wasting space with unnecessary DRIs, however.
+ */
+ if (cinfo->restart_interval != marker->last_restart_interval) {
+ emit_dri(cinfo);
+ marker->last_restart_interval = cinfo->restart_interval;
+ }
+
+ emit_sos(cinfo);
+}
+
+
+/*
+ * Write datastream trailer.
+ */
+
+METHODDEF(void)
+write_file_trailer (j_compress_ptr cinfo)
+{
+ emit_marker(cinfo, M_EOI);
+}
+
+
+/*
+ * Write an abbreviated table-specification datastream.
+ * This consists of SOI, DQT and DHT tables, and EOI.
+ * Any table that is defined and not marked sent_table = TRUE will be
+ * emitted. Note that all tables will be marked sent_table = TRUE at exit.
+ */
+
+METHODDEF(void)
+write_tables_only (j_compress_ptr cinfo)
+{
+ int i;
+
+ emit_marker(cinfo, M_SOI);
+
+ for (i = 0; i < NUM_QUANT_TBLS; i++) {
+ if (cinfo->quant_tbl_ptrs[i] != NULL)
+ (void) emit_dqt(cinfo, i);
+ }
+
+ if (! cinfo->arith_code) {
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
+ emit_dht(cinfo, i, FALSE);
+ if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
+ emit_dht(cinfo, i, TRUE);
+ }
+ }
+
+ emit_marker(cinfo, M_EOI);
+}
+
+
+/*
+ * Initialize the marker writer module.
+ */
+
+GLOBAL(void)
+jinit_marker_writer (j_compress_ptr cinfo)
+{
+ my_marker_ptr marker;
+
+ /* Create the subobject */
+ marker = (my_marker_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_marker_writer));
+ cinfo->marker = (struct jpeg_marker_writer *) marker;
+ /* Initialize method pointers */
+ marker->pub.write_file_header = write_file_header;
+ marker->pub.write_frame_header = write_frame_header;
+ marker->pub.write_scan_header = write_scan_header;
+ marker->pub.write_file_trailer = write_file_trailer;
+ marker->pub.write_tables_only = write_tables_only;
+ marker->pub.write_marker_header = write_marker_header;
+ marker->pub.write_marker_byte = write_marker_byte;
+ /* Initialize private state */
+ marker->last_restart_interval = 0;
+}
--- /dev/null
+/*
+ * jcmaster.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains master control logic for the JPEG compressor.
+ * These routines are concerned with parameter validation, initial setup,
+ * and inter-pass control (determining the number of passes and the work
+ * to be done in each pass).
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+
+
+/* Private state */
+
+typedef enum {
+ main_pass, /* input data, also do first output step */
+ huff_opt_pass, /* Huffman code optimization pass */
+ output_pass /* data output pass */
+} c_pass_type;
+
+typedef struct {
+ struct jpeg_comp_master pub; /* public fields */
+
+ c_pass_type pass_type; /* the type of the current pass */
+
+ int pass_number; /* # of passes completed */
+ int total_passes; /* total # of passes needed */
+
+ int scan_number; /* current index in scan_info[] */
+} my_comp_master;
+
+typedef my_comp_master * my_master_ptr;
+
+
+/*
+ * Support routines that do various essential calculations.
+ */
+
+LOCAL(void)
+initial_setup (j_compress_ptr cinfo)
+/* Do computations that are needed before master selection phase */
+{
+ int ci;
+ jpeg_component_info *compptr;
+ long samplesperrow;
+ JDIMENSION jd_samplesperrow;
+ int data_unit = cinfo->data_unit;
+
+ /* Sanity check on image dimensions */
+ if (cinfo->image_height <= 0 || cinfo->image_width <= 0
+ || cinfo->num_components <= 0 || cinfo->input_components <= 0)
+ ERREXIT(cinfo, JERR_EMPTY_IMAGE);
+
+ /* Make sure image isn't bigger than I can handle */
+ if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
+ (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
+ ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
+
+ /* Width of an input scanline must be representable as JDIMENSION. */
+ samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
+ jd_samplesperrow = (JDIMENSION) samplesperrow;
+ if ((long) jd_samplesperrow != samplesperrow)
+ ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
+
+ /* For now, precision must match compiled-in value... */
+ if (cinfo->data_precision != BITS_IN_JSAMPLE)
+ ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
+
+ /* Check that number of components won't exceed internal array sizes */
+ if (cinfo->num_components > MAX_COMPONENTS)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
+ MAX_COMPONENTS);
+
+ /* Compute maximum sampling factors; check factor validity */
+ cinfo->max_h_samp_factor = 1;
+ cinfo->max_v_samp_factor = 1;
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
+ compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
+ ERREXIT(cinfo, JERR_BAD_SAMPLING);
+ cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
+ compptr->h_samp_factor);
+ cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
+ compptr->v_samp_factor);
+ }
+
+ /* Compute dimensions of components */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Fill in the correct component_index value; don't rely on application */
+ compptr->component_index = ci;
+ /* For compression, we never do any codec-based processing. */
+ compptr->codec_data_unit = data_unit;
+ /* Size in data units */
+ compptr->width_in_data_units = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+ (long) (cinfo->max_h_samp_factor * data_unit));
+ compptr->height_in_data_units = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+ (long) (cinfo->max_v_samp_factor * data_unit));
+ /* Size in samples */
+ compptr->downsampled_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+ (long) cinfo->max_h_samp_factor);
+ compptr->downsampled_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+ (long) cinfo->max_v_samp_factor);
+ /* Mark component needed (this flag isn't actually used for compression) */
+ compptr->component_needed = TRUE;
+ }
+
+ /* Compute number of fully interleaved MCU rows (number of times that
+ * main controller will call coefficient controller).
+ */
+ cinfo->total_iMCU_rows = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height,
+ (long) (cinfo->max_v_samp_factor*data_unit));
+}
+
+#ifdef C_MULTISCAN_FILES_SUPPORTED
+#define NEED_SCAN_SCRIPT
+#else
+#ifdef C_LOSSLESS_SUPPORTED
+#define NEED_SCAN_SCRIPT
+#endif
+#endif
+
+#ifdef NEED_SCAN_SCRIPT
+
+LOCAL(void)
+validate_script (j_compress_ptr cinfo)
+/* Verify that the scan script in cinfo->scan_info[] is valid; also
+ * determine whether it uses progressive JPEG, and set cinfo->process.
+ */
+{
+ const jpeg_scan_info * scanptr;
+ int scanno, ncomps, ci, coefi, thisi;
+ int Ss, Se, Ah, Al;
+ boolean component_sent[MAX_COMPONENTS];
+#ifdef C_PROGRESSIVE_SUPPORTED
+ int * last_bitpos_ptr;
+ int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
+ /* -1 until that coefficient has been seen; then last Al for it */
+#endif
+
+ if (cinfo->num_scans <= 0)
+ ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
+
+#ifndef C_MULTISCAN_FILES_SUPPORTED
+ if (cinfo->num_scans > 1)
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+
+ scanptr = cinfo->scan_info;
+ if (cinfo->lossless) {
+#ifdef C_LOSSLESS_SUPPORTED
+ cinfo->process = JPROC_LOSSLESS;
+ for (ci = 0; ci < cinfo->num_components; ci++)
+ component_sent[ci] = FALSE;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ }
+ /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
+ * for progressive JPEG, no scan can have this.
+ */
+ else if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
+#ifdef C_PROGRESSIVE_SUPPORTED
+ cinfo->process = JPROC_PROGRESSIVE;
+ last_bitpos_ptr = & last_bitpos[0][0];
+ for (ci = 0; ci < cinfo->num_components; ci++)
+ for (coefi = 0; coefi < DCTSIZE2; coefi++)
+ *last_bitpos_ptr++ = -1;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ cinfo->process = JPROC_SEQUENTIAL;
+ for (ci = 0; ci < cinfo->num_components; ci++)
+ component_sent[ci] = FALSE;
+ }
+
+ for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
+ /* Validate component indexes */
+ ncomps = scanptr->comps_in_scan;
+ if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
+ for (ci = 0; ci < ncomps; ci++) {
+ thisi = scanptr->component_index[ci];
+ if (thisi < 0 || thisi >= cinfo->num_components)
+ ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
+ /* Components must appear in SOF order within each scan */
+ if (ci > 0 && thisi <= scanptr->component_index[ci-1])
+ ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
+ }
+ /* Validate progression parameters */
+ Ss = scanptr->Ss;
+ Se = scanptr->Se;
+ Ah = scanptr->Ah;
+ Al = scanptr->Al;
+ if (cinfo->process == JPROC_LOSSLESS) {
+#ifdef C_LOSSLESS_SUPPORTED
+ /* The JPEG spec simply gives the range 0..15 for Al (Pt), but that
+ * seems wrong: the upper bound ought to depend on data precision.
+ * Perhaps they really meant 0..N-1 for N-bit precision, which is what
+ * we allow here.
+ */
+ if (Ss < 1 || Ss > 7 || /* predictor selector */
+ Se != 0 || Ah != 0 ||
+ Al < 0 || Al >= cinfo->data_precision) /* point transform */
+ ERREXIT1(cinfo, JERR_BAD_LOSSLESS_SCRIPT, scanno);
+ /* Make sure components are not sent twice */
+ for (ci = 0; ci < ncomps; ci++) {
+ thisi = scanptr->component_index[ci];
+ if (component_sent[thisi])
+ ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
+ component_sent[thisi] = TRUE;
+ }
+#endif
+ } else if (cinfo->process == JPROC_PROGRESSIVE) {
+#ifdef C_PROGRESSIVE_SUPPORTED
+ /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
+ * seems wrong: the upper bound ought to depend on data precision.
+ * Perhaps they really meant 0..N+1 for N-bit precision.
+ * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
+ * out-of-range reconstructed DC values during the first DC scan,
+ * which might cause problems for some decoders.
+ */
+#if BITS_IN_JSAMPLE == 8
+#define MAX_AH_AL 10
+#else
+#define MAX_AH_AL 13
+#endif
+ if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
+ Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ if (Ss == 0) {
+ if (Se != 0) /* DC and AC together not OK */
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ } else {
+ if (ncomps != 1) /* AC scans must be for only one component */
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ }
+ for (ci = 0; ci < ncomps; ci++) {
+ last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
+ if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ for (coefi = Ss; coefi <= Se; coefi++) {
+ if (last_bitpos_ptr[coefi] < 0) {
+ /* first scan of this coefficient */
+ if (Ah != 0)
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ } else {
+ /* not first scan */
+ if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ }
+ last_bitpos_ptr[coefi] = Al;
+ }
+ }
+#endif
+ } else {
+ /* For sequential JPEG, all progression parameters must be these: */
+ if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
+ ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
+ /* Make sure components are not sent twice */
+ for (ci = 0; ci < ncomps; ci++) {
+ thisi = scanptr->component_index[ci];
+ if (component_sent[thisi])
+ ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
+ component_sent[thisi] = TRUE;
+ }
+ }
+ }
+
+ /* Now verify that everything got sent. */
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+#ifdef C_PROGRESSIVE_SUPPORTED
+ /* For progressive mode, we only check that at least some DC data
+ * got sent for each component; the spec does not require that all bits
+ * of all coefficients be transmitted. Would it be wiser to enforce
+ * transmission of all coefficient bits??
+ */
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ if (last_bitpos[ci][0] < 0)
+ ERREXIT(cinfo, JERR_MISSING_DATA);
+ }
+#endif
+ } else {
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ if (! component_sent[ci])
+ ERREXIT(cinfo, JERR_MISSING_DATA);
+ }
+ }
+}
+
+#endif /* NEED_SCAN_SCRIPT */
+
+
+LOCAL(void)
+select_scan_parameters (j_compress_ptr cinfo)
+/* Set up the scan parameters for the current scan */
+{
+ int ci;
+
+#ifdef NEED_SCAN_SCRIPT
+ if (cinfo->scan_info != NULL) {
+ /* Prepare for current scan --- the script is already validated */
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+ const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
+
+ cinfo->comps_in_scan = scanptr->comps_in_scan;
+ for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
+ cinfo->cur_comp_info[ci] =
+ &cinfo->comp_info[scanptr->component_index[ci]];
+ }
+ cinfo->Ss = scanptr->Ss;
+ cinfo->Se = scanptr->Se;
+ cinfo->Ah = scanptr->Ah;
+ cinfo->Al = scanptr->Al;
+ } else
+#endif
+ {
+ /* Prepare for single sequential-JPEG scan containing all components */
+ if (cinfo->num_components > MAX_COMPS_IN_SCAN)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
+ MAX_COMPS_IN_SCAN);
+ cinfo->comps_in_scan = cinfo->num_components;
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
+ }
+ if (cinfo->lossless) {
+#ifdef C_LOSSLESS_SUPPORTED
+ /* If we fall through to here, the user specified lossless, but did not
+ * provide a scan script.
+ */
+ ERREXIT(cinfo, JERR_NO_LOSSLESS_SCRIPT);
+#endif
+ } else {
+ cinfo->process = JPROC_SEQUENTIAL;
+ cinfo->Ss = 0;
+ cinfo->Se = DCTSIZE2-1;
+ cinfo->Ah = 0;
+ cinfo->Al = 0;
+ }
+ }
+}
+
+
+LOCAL(void)
+per_scan_setup (j_compress_ptr cinfo)
+/* Do computations that are needed before processing a JPEG scan */
+/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
+{
+ int ci, mcublks, tmp;
+ jpeg_component_info *compptr;
+ int data_unit = cinfo->data_unit;
+
+ if (cinfo->comps_in_scan == 1) {
+
+ /* Noninterleaved (single-component) scan */
+ compptr = cinfo->cur_comp_info[0];
+
+ /* Overall image size in MCUs */
+ cinfo->MCUs_per_row = compptr->width_in_data_units;
+ cinfo->MCU_rows_in_scan = compptr->height_in_data_units;
+
+ /* For noninterleaved scan, always one block per MCU */
+ compptr->MCU_width = 1;
+ compptr->MCU_height = 1;
+ compptr->MCU_data_units = 1;
+ compptr->MCU_sample_width = data_unit;
+ compptr->last_col_width = 1;
+ /* For noninterleaved scans, it is convenient to define last_row_height
+ * as the number of block rows present in the last iMCU row.
+ */
+ tmp = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (tmp == 0) tmp = compptr->v_samp_factor;
+ compptr->last_row_height = tmp;
+
+ /* Prepare array describing MCU composition */
+ cinfo->data_units_in_MCU = 1;
+ cinfo->MCU_membership[0] = 0;
+
+ } else {
+
+ /* Interleaved (multi-component) scan */
+ if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
+ MAX_COMPS_IN_SCAN);
+
+ /* Overall image size in MCUs */
+ cinfo->MCUs_per_row = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width,
+ (long) (cinfo->max_h_samp_factor*data_unit));
+ cinfo->MCU_rows_in_scan = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height,
+ (long) (cinfo->max_v_samp_factor*data_unit));
+
+ cinfo->data_units_in_MCU = 0;
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* Sampling factors give # of blocks of component in each MCU */
+ compptr->MCU_width = compptr->h_samp_factor;
+ compptr->MCU_height = compptr->v_samp_factor;
+ compptr->MCU_data_units = compptr->MCU_width * compptr->MCU_height;
+ compptr->MCU_sample_width = compptr->MCU_width * data_unit;
+ /* Figure number of non-dummy blocks in last MCU column & row */
+ tmp = (int) (compptr->width_in_data_units % compptr->MCU_width);
+ if (tmp == 0) tmp = compptr->MCU_width;
+ compptr->last_col_width = tmp;
+ tmp = (int) (compptr->height_in_data_units % compptr->MCU_height);
+ if (tmp == 0) tmp = compptr->MCU_height;
+ compptr->last_row_height = tmp;
+ /* Prepare array describing MCU composition */
+ mcublks = compptr->MCU_data_units;
+ if (cinfo->data_units_in_MCU + mcublks > C_MAX_DATA_UNITS_IN_MCU)
+ ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
+ while (mcublks-- > 0) {
+ cinfo->MCU_membership[cinfo->data_units_in_MCU++] = ci;
+ }
+ }
+
+ }
+
+ /* Convert restart specified in rows to actual MCU count. */
+ /* Note that count must fit in 16 bits, so we provide limiting. */
+ if (cinfo->restart_in_rows > 0) {
+ long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
+ cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
+ }
+}
+
+
+/*
+ * Per-pass setup.
+ * This is called at the beginning of each pass. We determine which modules
+ * will be active during this pass and give them appropriate start_pass calls.
+ * We also set is_last_pass to indicate whether any more passes will be
+ * required.
+ */
+
+METHODDEF(void)
+prepare_for_pass (j_compress_ptr cinfo)
+{
+ /* j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec; */
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+
+ switch (master->pass_type) {
+ case main_pass:
+ /* Initial pass: will collect input data, and do either Huffman
+ * optimization or data output for the first scan.
+ */
+ select_scan_parameters(cinfo);
+ per_scan_setup(cinfo);
+ if (! cinfo->raw_data_in) {
+ (*cinfo->cconvert->start_pass) (cinfo);
+ (*cinfo->downsample->start_pass) (cinfo);
+ (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
+ }
+ (*cinfo->codec->entropy_start_pass) (cinfo, cinfo->optimize_coding);
+ (*cinfo->codec->start_pass) (cinfo,
+ (master->total_passes > 1 ?
+ JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
+ (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
+ if (cinfo->optimize_coding) {
+ /* No immediate data output; postpone writing frame/scan headers */
+ master->pub.call_pass_startup = FALSE;
+ } else {
+ /* Will write frame/scan headers at first jpeg_write_scanlines call */
+ master->pub.call_pass_startup = TRUE;
+ }
+ break;
+#ifdef ENTROPY_OPT_SUPPORTED
+ case huff_opt_pass:
+ /* Do Huffman optimization for a scan after the first one. */
+ select_scan_parameters(cinfo);
+ per_scan_setup(cinfo);
+ if ((*cinfo->codec->need_optimization_pass) (cinfo)) {
+ (*cinfo->codec->entropy_start_pass) (cinfo, TRUE);
+ (*cinfo->codec->start_pass) (cinfo, JBUF_CRANK_DEST);
+ master->pub.call_pass_startup = FALSE;
+ break;
+ }
+ /* Special case: Huffman DC refinement scans need no Huffman table
+ * and therefore we can skip the optimization pass for them.
+ */
+ master->pass_type = output_pass;
+ master->pass_number++;
+ /*FALLTHROUGH*/
+#endif
+ case output_pass:
+ /* Do a data-output pass. */
+ /* We need not repeat per-scan setup if prior optimization pass did it. */
+ if (! cinfo->optimize_coding) {
+ select_scan_parameters(cinfo);
+ per_scan_setup(cinfo);
+ }
+ (*cinfo->codec->entropy_start_pass) (cinfo, FALSE);
+ (*cinfo->codec->start_pass) (cinfo, JBUF_CRANK_DEST);
+ /* We emit frame/scan headers now */
+ if (master->scan_number == 0)
+ (*cinfo->marker->write_frame_header) (cinfo);
+ (*cinfo->marker->write_scan_header) (cinfo);
+ master->pub.call_pass_startup = FALSE;
+ break;
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ }
+
+ master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
+
+ /* Set up progress monitor's pass info if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->completed_passes = master->pass_number;
+ cinfo->progress->total_passes = master->total_passes;
+ }
+}
+
+
+/*
+ * Special start-of-pass hook.
+ * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
+ * In single-pass processing, we need this hook because we don't want to
+ * write frame/scan headers during jpeg_start_compress; we want to let the
+ * application write COM markers etc. between jpeg_start_compress and the
+ * jpeg_write_scanlines loop.
+ * In multi-pass processing, this routine is not used.
+ */
+
+METHODDEF(void)
+pass_startup (j_compress_ptr cinfo)
+{
+ cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
+
+ (*cinfo->marker->write_frame_header) (cinfo);
+ (*cinfo->marker->write_scan_header) (cinfo);
+}
+
+
+/*
+ * Finish up at end of pass.
+ */
+
+METHODDEF(void)
+finish_pass_master (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+
+ /* The entropy coder always needs an end-of-pass call,
+ * either to analyze statistics or to flush its output buffer.
+ */
+ (*lossyc->pub.entropy_finish_pass) (cinfo);
+
+ /* Update state for next pass */
+ switch (master->pass_type) {
+ case main_pass:
+ /* next pass is either output of scan 0 (after optimization)
+ * or output of scan 1 (if no optimization).
+ */
+ master->pass_type = output_pass;
+ if (! cinfo->optimize_coding)
+ master->scan_number++;
+ break;
+ case huff_opt_pass:
+ /* next pass is always output of current scan */
+ master->pass_type = output_pass;
+ break;
+ case output_pass:
+ /* next pass is either optimization or output of next scan */
+ if (cinfo->optimize_coding)
+ master->pass_type = huff_opt_pass;
+ master->scan_number++;
+ break;
+ }
+
+ master->pass_number++;
+}
+
+
+/*
+ * Initialize master compression control.
+ */
+
+GLOBAL(void)
+jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
+{
+ my_master_ptr master;
+
+ master = (my_master_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_comp_master));
+ cinfo->master = (struct jpeg_comp_master *) master;
+ master->pub.prepare_for_pass = prepare_for_pass;
+ master->pub.pass_startup = pass_startup;
+ master->pub.finish_pass = finish_pass_master;
+ master->pub.is_last_pass = FALSE;
+
+ cinfo->data_unit = cinfo->lossless ? 1 : DCTSIZE;
+
+ /* Validate parameters, determine derived values */
+ initial_setup(cinfo);
+
+ if (cinfo->scan_info != NULL) {
+#ifdef NEED_SCAN_SCRIPT
+ validate_script(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ cinfo->process = JPROC_SEQUENTIAL;
+ cinfo->num_scans = 1;
+ }
+
+ if ((cinfo->arith_code == 0) &&
+ (cinfo->process == JPROC_PROGRESSIVE || /* TEMPORARY HACK ??? */
+ cinfo->process == JPROC_LOSSLESS))
+ cinfo->optimize_coding = TRUE; /* assume default tables no good for
+ * progressive mode or lossless mode */
+
+ /* Initialize my private state */
+ if (transcode_only) {
+ /* no main pass in transcoding */
+ if (cinfo->optimize_coding)
+ master->pass_type = huff_opt_pass;
+ else
+ master->pass_type = output_pass;
+ } else {
+ /* for normal compression, first pass is always this type: */
+ master->pass_type = main_pass;
+ }
+ master->scan_number = 0;
+ master->pass_number = 0;
+ if (cinfo->optimize_coding)
+ master->total_passes = cinfo->num_scans * 2;
+ else
+ master->total_passes = cinfo->num_scans;
+}
--- /dev/null
+/*
+ * jcodec.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains utility functions for the JPEG codec(s).
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h"
+#include "jlossls.h"
+
+
+/*
+ * Initialize the compression codec.
+ * This is called only once, during master selection.
+ */
+
+GLOBAL(void)
+jinit_c_codec (j_compress_ptr cinfo)
+{
+ if (cinfo->process == JPROC_LOSSLESS) {
+#ifdef C_LOSSLESS_SUPPORTED
+ jinit_lossless_c_codec(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else
+ jinit_lossy_c_codec(cinfo);
+}
+
+
+/*
+ * Initialize the decompression codec.
+ * This is called only once, during master selection.
+ */
+
+GLOBAL(void)
+jinit_d_codec (j_decompress_ptr cinfo)
+{
+ if (cinfo->process == JPROC_LOSSLESS) {
+#ifdef D_LOSSLESS_SUPPORTED
+ jinit_lossless_d_codec(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else
+ jinit_lossy_d_codec(cinfo);
+}
--- /dev/null
+/*
+ * jcomapi.c
+ *
+ * Copyright (C) 1994-1997, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains application interface routines that are used for both
+ * compression and decompression.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Abort processing of a JPEG compression or decompression operation,
+ * but don't destroy the object itself.
+ *
+ * For this, we merely clean up all the nonpermanent memory pools.
+ * Note that temp files (virtual arrays) are not allowed to belong to
+ * the permanent pool, so we will be able to close all temp files here.
+ * Closing a data source or destination, if necessary, is the application's
+ * responsibility.
+ */
+
+GLOBAL(void)
+jpeg_abort (j_common_ptr cinfo)
+{
+ int pool;
+
+ /* Do nothing if called on a not-initialized or destroyed JPEG object. */
+ if (cinfo->mem == NULL)
+ return;
+
+ /* Releasing pools in reverse order might help avoid fragmentation
+ * with some (brain-damaged) malloc libraries.
+ */
+ for (pool = JPOOL_NUMPOOLS-1; pool > JPOOL_PERMANENT; pool--) {
+ (*cinfo->mem->free_pool) (cinfo, pool);
+ }
+
+ /* Reset overall state for possible reuse of object */
+ if (cinfo->is_decompressor) {
+ cinfo->global_state = DSTATE_START;
+ /* Try to keep application from accessing now-deleted marker list.
+ * A bit kludgy to do it here, but this is the most central place.
+ */
+ ((j_decompress_ptr) cinfo)->marker_list = NULL;
+ } else {
+ cinfo->global_state = CSTATE_START;
+ }
+}
+
+
+/*
+ * Destruction of a JPEG object.
+ *
+ * Everything gets deallocated except the master jpeg_compress_struct itself
+ * and the error manager struct. Both of these are supplied by the application
+ * and must be freed, if necessary, by the application. (Often they are on
+ * the stack and so don't need to be freed anyway.)
+ * Closing a data source or destination, if necessary, is the application's
+ * responsibility.
+ */
+
+GLOBAL(void)
+jpeg_destroy (j_common_ptr cinfo)
+{
+ /* We need only tell the memory manager to release everything. */
+ /* NB: mem pointer is NULL if memory mgr failed to initialize. */
+ if (cinfo->mem != NULL)
+ (*cinfo->mem->self_destruct) (cinfo);
+ cinfo->mem = NULL; /* be safe if jpeg_destroy is called twice */
+ cinfo->global_state = 0; /* mark it destroyed */
+}
+
+
+/*
+ * Convenience routines for allocating quantization and Huffman tables.
+ * (Would jutils.c be a more reasonable place to put these?)
+ */
+
+GLOBAL(JQUANT_TBL *)
+jpeg_alloc_quant_table (j_common_ptr cinfo)
+{
+ JQUANT_TBL *tbl;
+
+ tbl = (JQUANT_TBL *)
+ (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JQUANT_TBL));
+ tbl->sent_table = FALSE; /* make sure this is false in any new table */
+ return tbl;
+}
+
+
+GLOBAL(JHUFF_TBL *)
+jpeg_alloc_huff_table (j_common_ptr cinfo)
+{
+ JHUFF_TBL *tbl;
+
+ tbl = (JHUFF_TBL *)
+ (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JHUFF_TBL));
+ tbl->sent_table = FALSE; /* make sure this is false in any new table */
+ return tbl;
+}
--- /dev/null
+/*
+ * jconfig.doc
+ *
+ * Copyright (C) 1991-1994, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file documents the configuration options that are required to
+ * customize the JPEG software for a particular system.
+ *
+ * The actual configuration options for a particular installation are stored
+ * in jconfig.h. On many machines, jconfig.h can be generated automatically
+ * or copied from one of the "canned" jconfig files that we supply. But if
+ * you need to generate a jconfig.h file by hand, this file tells you how.
+ *
+ * DO NOT EDIT THIS FILE --- IT WON'T ACCOMPLISH ANYTHING.
+ * EDIT A COPY NAMED JCONFIG.H.
+ */
+
+
+/*
+ * These symbols indicate the properties of your machine or compiler.
+ * #define the symbol if yes, #undef it if no.
+ */
+
+/* Does your compiler support function prototypes?
+ * (If not, you also need to use ansi2knr, see install.doc)
+ */
+#define HAVE_PROTOTYPES
+
+/* Does your compiler support the declaration "unsigned char" ?
+ * How about "unsigned short" ?
+ */
+#define HAVE_UNSIGNED_CHAR
+#define HAVE_UNSIGNED_SHORT
+
+/* Define "void" as "char" if your compiler doesn't know about type void.
+ * NOTE: be sure to define void such that "void *" represents the most general
+ * pointer type, e.g., that returned by malloc().
+ */
+/* #define void char */
+
+/* Define "const" as empty if your compiler doesn't know the "const" keyword.
+ */
+/* #define const */
+
+/* Define this if an ordinary "char" type is unsigned.
+ * If you're not sure, leaving it undefined will work at some cost in speed.
+ * If you defined HAVE_UNSIGNED_CHAR then the speed difference is minimal.
+ */
+#undef CHAR_IS_UNSIGNED
+
+/* Define this if your system has an ANSI-conforming <stddef.h> file.
+ */
+#define HAVE_STDDEF_H
+
+/* Define this if your system has an ANSI-conforming <stdlib.h> file.
+ */
+#define HAVE_STDLIB_H
+
+/* Define this if your system does not have an ANSI/SysV <string.h>,
+ * but does have a BSD-style <strings.h>.
+ */
+#undef NEED_BSD_STRINGS
+
+/* Define this if your system does not provide typedef size_t in any of the
+ * ANSI-standard places (stddef.h, stdlib.h, or stdio.h), but places it in
+ * <sys/types.h> instead.
+ */
+#undef NEED_SYS_TYPES_H
+
+/* For 80x86 machines, you need to define NEED_FAR_POINTERS,
+ * unless you are using a large-data memory model or 80386 flat-memory mode.
+ * On less brain-damaged CPUs this symbol must not be defined.
+ * (Defining this symbol causes large data structures to be referenced through
+ * "far" pointers and to be allocated with a special version of malloc.)
+ */
+#undef NEED_FAR_POINTERS
+
+/* Define this if your linker needs global names to be unique in less
+ * than the first 15 characters.
+ */
+#undef NEED_SHORT_EXTERNAL_NAMES
+
+/* Although a real ANSI C compiler can deal perfectly well with pointers to
+ * unspecified structures (see "incomplete types" in the spec), a few pre-ANSI
+ * and pseudo-ANSI compilers get confused. To keep one of these bozos happy,
+ * define INCOMPLETE_TYPES_BROKEN. This is not recommended unless you
+ * actually get "missing structure definition" warnings or errors while
+ * compiling the JPEG code.
+ */
+#undef INCOMPLETE_TYPES_BROKEN
+
+
+/*
+ * The following options affect code selection within the JPEG library,
+ * but they don't need to be visible to applications using the library.
+ * To minimize application namespace pollution, the symbols won't be
+ * defined unless JPEG_INTERNALS has been defined.
+ */
+
+#ifdef JPEG_INTERNALS
+
+/* Define this if your compiler implements ">>" on signed values as a logical
+ * (unsigned) shift; leave it undefined if ">>" is a signed (arithmetic) shift,
+ * which is the normal and rational definition.
+ */
+#undef RIGHT_SHIFT_IS_UNSIGNED
+
+
+#endif /* JPEG_INTERNALS */
+
+
+/*
+ * The remaining options do not affect the JPEG library proper,
+ * but only the sample applications cjpeg/djpeg (see cjpeg.c, djpeg.c).
+ * Other applications can ignore these.
+ */
+
+#ifdef JPEG_CJPEG_DJPEG
+
+/* These defines indicate which image (non-JPEG) file formats are allowed. */
+
+#define BMP_SUPPORTED /* BMP image file format */
+#define GIF_SUPPORTED /* GIF image file format */
+#define PPM_SUPPORTED /* PBMPLUS PPM/PGM image file format */
+#undef RLE_SUPPORTED /* Utah RLE image file format */
+#define TARGA_SUPPORTED /* Targa image file format */
+
+/* Define this if you want to name both input and output files on the command
+ * line, rather than using stdout and optionally stdin. You MUST do this if
+ * your system can't cope with binary I/O to stdin/stdout. See comments at
+ * head of cjpeg.c or djpeg.c.
+ */
+#undef TWO_FILE_COMMANDLINE
+
+/* Define this if your system needs explicit cleanup of temporary files.
+ * This is crucial under MS-DOS, where the temporary "files" may be areas
+ * of extended memory; on most other systems it's not as important.
+ */
+#undef NEED_SIGNAL_CATCHER
+
+/* By default, we open image files with fopen(...,"rb") or fopen(...,"wb").
+ * This is necessary on systems that distinguish text files from binary files,
+ * and is harmless on most systems that don't. If you have one of the rare
+ * systems that complains about the "b" spec, define this symbol.
+ */
+#undef DONT_USE_B_MODE
+
+/* Define this if you want percent-done progress reports from cjpeg/djpeg.
+ */
+#undef PROGRESS_REPORT
+
+
+#endif /* JPEG_CJPEG_DJPEG */
--- /dev/null
+/* jconfig.h --- source file edited by configure script */
+/* see jconfig.doc for explanations */
+
+#define HAVE_PROTOTYPES
+#define HAVE_UNSIGNED_CHAR
+#define HAVE_UNSIGNED_SHORT
+#undef void
+#undef const
+#undef CHAR_IS_UNSIGNED
+#ifndef HAVE_STDDEF_H
+#define HAVE_STDDEF_H
+#endif
+#ifndef HAVE_STDLIB_H
+#define HAVE_STDLIB_H
+#endif
+#undef NEED_BSD_STRINGS
+#undef NEED_SYS_TYPES_H
+#undef NEED_FAR_POINTERS
+#undef NEED_SHORT_EXTERNAL_NAMES
+/* Define this if you get warnings about undefined structures. */
+#undef INCOMPLETE_TYPES_BROKEN
+
+
+#if defined(_WIN32) && !(defined(__CYGWIN__) || defined(__MINGW32__))
+/* Define "boolean" as unsigned char, not int, per Windows custom */
+/* don't conflict if rpcndr.h already read; Note that the w32api headers
+ used by Cygwin and Mingw do not define "boolean", so jmorecfg.h
+ handles it later. */
+#ifndef __RPCNDR_H__
+typedef unsigned char boolean;
+#endif
+#define HAVE_BOOLEAN /* prevent jmorecfg.h from redefining it */
+#endif
+
+#ifdef JPEG_INTERNALS
+
+#undef RIGHT_SHIFT_IS_UNSIGNED
+#define INLINE
+/* These are for configuring the JPEG memory manager. */
+#undef DEFAULT_MAX_MEM
+#undef NO_MKTEMP
+
+#endif /* JPEG_INTERNALS */
+
+#ifdef JPEG_CJPEG_DJPEG
+
+#define BMP_SUPPORTED /* BMP image file format */
+#define GIF_SUPPORTED /* GIF image file format */
+#define PPM_SUPPORTED /* PBMPLUS PPM/PGM image file format */
+#undef RLE_SUPPORTED /* Utah RLE image file format */
+#define TARGA_SUPPORTED /* Targa image file format */
+
+#undef TWO_FILE_COMMANDLINE
+#undef NEED_SIGNAL_CATCHER
+#undef DONT_USE_B_MODE
+
+/* Define this if you want percent-done progress reports from cjpeg/djpeg. */
+#undef PROGRESS_REPORT
+
+#endif /* JPEG_CJPEG_DJPEG */
+
+
+/* names mangling */
+
+#include "@BITS_TYPE_JPEG_MANGLE_NAME@"
+
+#if defined(__BORLANDC__)
+#pragma warn -8004 /* Disable "foo is assigned a value that is never used." */
+#endif
--- /dev/null
+/*
+ * jcparam.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains optional default-setting code for the JPEG compressor.
+ * Applications do not have to use this file, but those that don't use it
+ * must know a lot more about the innards of the JPEG code.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Quantization table setup routines
+ */
+
+GLOBAL(void)
+jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl,
+ const unsigned int *basic_table,
+ int scale_factor, boolean force_baseline)
+/* Define a quantization table equal to the basic_table times
+ * a scale factor (given as a percentage).
+ * If force_baseline is TRUE, the computed quantization table entries
+ * are limited to 1..255 for JPEG baseline compatibility.
+ */
+{
+ JQUANT_TBL ** qtblptr;
+ int i;
+ long temp;
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS)
+ ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl);
+
+ qtblptr = & cinfo->quant_tbl_ptrs[which_tbl];
+
+ if (*qtblptr == NULL)
+ *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo);
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ temp = ((long) basic_table[i] * scale_factor + 50L) / 100L;
+ /* limit the values to the valid range */
+ if (temp <= 0L) temp = 1L;
+ if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */
+ if (force_baseline && temp > 255L)
+ temp = 255L; /* limit to baseline range if requested */
+ (*qtblptr)->quantval[i] = (UINT16) temp;
+ }
+
+ /* Initialize sent_table FALSE so table will be written to JPEG file. */
+ (*qtblptr)->sent_table = FALSE;
+}
+
+
+GLOBAL(void)
+jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
+ boolean force_baseline)
+/* Set or change the 'quality' (quantization) setting, using default tables
+ * and a straight percentage-scaling quality scale. In most cases it's better
+ * to use jpeg_set_quality (below); this entry point is provided for
+ * applications that insist on a linear percentage scaling.
+ */
+{
+ /* These are the sample quantization tables given in JPEG spec section K.1.
+ * The spec says that the values given produce "good" quality, and
+ * when divided by 2, "very good" quality.
+ */
+ static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
+ 16, 11, 10, 16, 24, 40, 51, 61,
+ 12, 12, 14, 19, 26, 58, 60, 55,
+ 14, 13, 16, 24, 40, 57, 69, 56,
+ 14, 17, 22, 29, 51, 87, 80, 62,
+ 18, 22, 37, 56, 68, 109, 103, 77,
+ 24, 35, 55, 64, 81, 104, 113, 92,
+ 49, 64, 78, 87, 103, 121, 120, 101,
+ 72, 92, 95, 98, 112, 100, 103, 99
+ };
+ static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
+ 17, 18, 24, 47, 99, 99, 99, 99,
+ 18, 21, 26, 66, 99, 99, 99, 99,
+ 24, 26, 56, 99, 99, 99, 99, 99,
+ 47, 66, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99
+ };
+
+ /* Set up two quantization tables using the specified scaling */
+ jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
+ scale_factor, force_baseline);
+ jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
+ scale_factor, force_baseline);
+}
+
+
+GLOBAL(int)
+jpeg_quality_scaling (int quality)
+/* Convert a user-specified quality rating to a percentage scaling factor
+ * for an underlying quantization table, using our recommended scaling curve.
+ * The input 'quality' factor should be 0 (terrible) to 100 (very good).
+ */
+{
+ /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */
+ if (quality <= 0) quality = 1;
+ if (quality > 100) quality = 100;
+
+ /* The basic table is used as-is (scaling 100) for a quality of 50.
+ * Qualities 50..100 are converted to scaling percentage 200 - 2*Q;
+ * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table
+ * to make all the table entries 1 (hence, minimum quantization loss).
+ * Qualities 1..50 are converted to scaling percentage 5000/Q.
+ */
+ if (quality < 50)
+ quality = 5000 / quality;
+ else
+ quality = 200 - quality*2;
+
+ return quality;
+}
+
+
+GLOBAL(void)
+jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline)
+/* Set or change the 'quality' (quantization) setting, using default tables.
+ * This is the standard quality-adjusting entry point for typical user
+ * interfaces; only those who want detailed control over quantization tables
+ * would use the preceding three routines directly.
+ */
+{
+ /* Convert user 0-100 rating to percentage scaling */
+ quality = jpeg_quality_scaling(quality);
+
+ /* Set up standard quality tables */
+ jpeg_set_linear_quality(cinfo, quality, force_baseline);
+}
+
+
+/*
+ * Huffman table setup routines
+ */
+
+LOCAL(void)
+add_huff_table (j_compress_ptr cinfo,
+ JHUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val)
+/* Define a Huffman table */
+{
+ int nsymbols, len;
+
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+
+ /* Copy the number-of-symbols-of-each-code-length counts */
+ MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
+
+ /* Validate the counts. We do this here mainly so we can copy the right
+ * number of symbols from the val[] array, without risking marching off
+ * the end of memory. jchuff.c will do a more thorough test later.
+ */
+ nsymbols = 0;
+ for (len = 1; len <= 16; len++)
+ nsymbols += bits[len];
+ if (nsymbols < 1 || nsymbols > 256)
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+
+ MEMCOPY((*htblptr)->huffval, val, nsymbols * SIZEOF(UINT8));
+
+ /* Initialize sent_table FALSE so table will be written to JPEG file. */
+ (*htblptr)->sent_table = FALSE;
+}
+
+
+LOCAL(void)
+std_huff_tables (j_compress_ptr cinfo)
+/* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
+/* IMPORTANT: these are only valid for 8-bit data precision! */
+{
+ static const UINT8 bits_dc_luminance[17] =
+ { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
+ static const UINT8 val_dc_luminance[] =
+ { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
+
+ static const UINT8 bits_dc_chrominance[17] =
+ { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
+ static const UINT8 val_dc_chrominance[] =
+ { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
+
+ static const UINT8 bits_ac_luminance[17] =
+ { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
+ static const UINT8 val_ac_luminance[] =
+ { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
+ 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
+ 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
+ 0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
+ 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
+ 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
+ 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
+ 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
+ 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
+ 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
+ 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
+ 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
+ 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
+ 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+ 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
+ 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
+ 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
+ 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
+ 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
+ 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
+ 0xf9, 0xfa };
+
+ static const UINT8 bits_ac_chrominance[17] =
+ { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
+ static const UINT8 val_ac_chrominance[] =
+ { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
+ 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
+ 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
+ 0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
+ 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
+ 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
+ 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
+ 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
+ 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
+ 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+ 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
+ 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+ 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
+ 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
+ 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
+ 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
+ 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
+ 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
+ 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
+ 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
+ 0xf9, 0xfa };
+
+ add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0],
+ bits_dc_luminance, val_dc_luminance);
+ add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0],
+ bits_ac_luminance, val_ac_luminance);
+ add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1],
+ bits_dc_chrominance, val_dc_chrominance);
+ add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1],
+ bits_ac_chrominance, val_ac_chrominance);
+}
+
+
+/*
+ * Default parameter setup for compression.
+ *
+ * Applications that don't choose to use this routine must do their
+ * own setup of all these parameters. Alternately, you can call this
+ * to establish defaults and then alter parameters selectively. This
+ * is the recommended approach since, if we add any new parameters,
+ * your code will still work (they'll be set to reasonable defaults).
+ */
+
+GLOBAL(void)
+jpeg_set_defaults (j_compress_ptr cinfo)
+{
+ int i;
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ /* Allocate comp_info array large enough for maximum component count.
+ * Array is made permanent in case application wants to compress
+ * multiple images at same param settings.
+ */
+ if (cinfo->comp_info == NULL)
+ cinfo->comp_info = (jpeg_component_info *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ MAX_COMPONENTS * SIZEOF(jpeg_component_info));
+
+ /* Initialize everything not dependent on the color space */
+
+ cinfo->lossless = FALSE;
+ cinfo->data_precision = BITS_IN_JSAMPLE;
+ /* Set up two quantization tables using default quality of 75 */
+ jpeg_set_quality(cinfo, 75, TRUE);
+ /* Set up two Huffman tables */
+ std_huff_tables(cinfo);
+
+ /* Initialize default arithmetic coding conditioning */
+ for (i = 0; i < NUM_ARITH_TBLS; i++) {
+ cinfo->arith_dc_L[i] = 0;
+ cinfo->arith_dc_U[i] = 1;
+ cinfo->arith_ac_K[i] = 5;
+ }
+
+ /* Default is no multiple-scan output */
+ cinfo->scan_info = NULL;
+ cinfo->num_scans = 0;
+
+ /* Expect normal source image, not raw downsampled data */
+ cinfo->raw_data_in = FALSE;
+
+ /* Use Huffman coding, not arithmetic coding, by default */
+ cinfo->arith_code = FALSE;
+
+ /* By default, don't do extra passes to optimize entropy coding */
+ cinfo->optimize_coding = FALSE;
+ /* The standard Huffman tables are only valid for 8-bit data precision.
+ * If the precision is higher, force optimization on so that usable
+ * tables will be computed. This test can be removed if default tables
+ * are supplied that are valid for the desired precision.
+ */
+ if (cinfo->data_precision > 8)
+ cinfo->optimize_coding = TRUE;
+
+ /* By default, use the simpler non-cosited sampling alignment */
+ cinfo->CCIR601_sampling = FALSE;
+
+ /* No input smoothing */
+ cinfo->smoothing_factor = 0;
+
+ /* DCT algorithm preference */
+ cinfo->dct_method = JDCT_DEFAULT;
+
+ /* No restart markers */
+ cinfo->restart_interval = 0;
+ cinfo->restart_in_rows = 0;
+
+ /* Fill in default JFIF marker parameters. Note that whether the marker
+ * will actually be written is determined by jpeg_set_colorspace.
+ *
+ * By default, the library emits JFIF version code 1.01.
+ * An application that wants to emit JFIF 1.02 extension markers should set
+ * JFIF_minor_version to 2. We could probably get away with just defaulting
+ * to 1.02, but there may still be some decoders in use that will complain
+ * about that; saying 1.01 should minimize compatibility problems.
+ */
+ cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */
+ cinfo->JFIF_minor_version = 1;
+ cinfo->density_unit = 0; /* Pixel size is unknown by default */
+ cinfo->X_density = 1; /* Pixel aspect ratio is square by default */
+ cinfo->Y_density = 1;
+
+ /* Choose JPEG colorspace based on input space, set defaults accordingly */
+
+ jpeg_default_colorspace(cinfo);
+}
+
+
+/*
+ * Select an appropriate JPEG colorspace for in_color_space.
+ */
+
+GLOBAL(void)
+jpeg_default_colorspace (j_compress_ptr cinfo)
+{
+ if (cinfo->lossless)
+ jpeg_set_colorspace(cinfo, cinfo->in_color_space);
+ else { /* lossy */
+ switch (cinfo->in_color_space) {
+ case JCS_GRAYSCALE:
+ jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
+ break;
+ case JCS_RGB:
+ jpeg_set_colorspace(cinfo, JCS_YCbCr);
+ break;
+ case JCS_YCbCr:
+ jpeg_set_colorspace(cinfo, JCS_YCbCr);
+ break;
+ case JCS_CMYK:
+ jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */
+ break;
+ case JCS_YCCK:
+ jpeg_set_colorspace(cinfo, JCS_YCCK);
+ break;
+ case JCS_UNKNOWN:
+ jpeg_set_colorspace(cinfo, JCS_UNKNOWN);
+ break;
+ default:
+ ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+ }
+ }
+}
+
+
+/*
+ * Set the JPEG colorspace, and choose colorspace-dependent default values.
+ */
+
+GLOBAL(void)
+jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
+{
+ jpeg_component_info * compptr;
+ int ci;
+
+#define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \
+ (compptr = &cinfo->comp_info[index], \
+ compptr->component_id = (id), \
+ compptr->h_samp_factor = (hsamp), \
+ compptr->v_samp_factor = (vsamp), \
+ compptr->quant_tbl_no = (quant), \
+ compptr->dc_tbl_no = (dctbl), \
+ compptr->ac_tbl_no = (actbl) )
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ /* For all colorspaces, we use Q and Huff tables 0 for luminance components,
+ * tables 1 for chrominance components.
+ */
+
+ cinfo->jpeg_color_space = colorspace;
+
+ cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */
+ cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */
+
+ switch (colorspace) {
+ case JCS_GRAYSCALE:
+ cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
+ cinfo->num_components = 1;
+ /* JFIF specifies component ID 1 */
+ SET_COMP(0, 1, 1,1, 0, 0,0);
+ break;
+ case JCS_RGB:
+ cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
+ cinfo->num_components = 3;
+ SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
+ SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
+ SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
+ break;
+ case JCS_YCbCr:
+ cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
+ cinfo->num_components = 3;
+ /* JFIF specifies component IDs 1,2,3 */
+ if (cinfo->lossless) {
+ SET_COMP(0, 1, 1,1, 0, 0,0);
+ SET_COMP(1, 2, 1,1, 1, 1,1);
+ SET_COMP(2, 3, 1,1, 1, 1,1);
+ } else { /* lossy */
+ /* We default to 2x2 subsamples of chrominance */
+ SET_COMP(0, 1, 2,2, 0, 0,0);
+ SET_COMP(1, 2, 1,1, 1, 1,1);
+ SET_COMP(2, 3, 1,1, 1, 1,1);
+ }
+ break;
+ case JCS_CMYK:
+ cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
+ cinfo->num_components = 4;
+ SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
+ SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
+ SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
+ SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
+ break;
+ case JCS_YCCK:
+ cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
+ cinfo->num_components = 4;
+ if (cinfo->lossless) {
+ SET_COMP(0, 1, 1,1, 0, 0,0);
+ SET_COMP(1, 2, 1,1, 1, 1,1);
+ SET_COMP(2, 3, 1,1, 1, 1,1);
+ SET_COMP(3, 4, 1,1, 0, 0,0);
+ } else { /* lossy */
+ SET_COMP(0, 1, 2,2, 0, 0,0);
+ SET_COMP(1, 2, 1,1, 1, 1,1);
+ SET_COMP(2, 3, 1,1, 1, 1,1);
+ SET_COMP(3, 4, 2,2, 0, 0,0);
+ }
+ break;
+ case JCS_UNKNOWN:
+ cinfo->num_components = cinfo->input_components;
+ if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
+ MAX_COMPONENTS);
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ SET_COMP(ci, ci, 1,1, 0, 0,0);
+ }
+ break;
+ default:
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ }
+}
+
+
+#ifdef C_PROGRESSIVE_SUPPORTED
+
+LOCAL(jpeg_scan_info *)
+fill_scans (jpeg_scan_info * scanptr, int ncomps,
+ int Ss, int Se, int Ah, int Al)
+/* Support routine: generate one scan for each component */
+{
+ int ci;
+
+ for (ci = 0; ci < ncomps; ci++) {
+ scanptr->comps_in_scan = 1;
+ scanptr->component_index[0] = ci;
+ scanptr->Ss = Ss;
+ scanptr->Se = Se;
+ scanptr->Ah = Ah;
+ scanptr->Al = Al;
+ scanptr++;
+ }
+ return scanptr;
+}
+
+
+LOCAL(jpeg_scan_info *)
+fill_a_scan (jpeg_scan_info * scanptr, int ci,
+ int Ss, int Se, int Ah, int Al)
+/* Support routine: generate one scan for specified component */
+{
+ scanptr->comps_in_scan = 1;
+ scanptr->component_index[0] = ci;
+ scanptr->Ss = Ss;
+ scanptr->Se = Se;
+ scanptr->Ah = Ah;
+ scanptr->Al = Al;
+ scanptr++;
+ return scanptr;
+}
+
+LOCAL(jpeg_scan_info *)
+fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al)
+/* Support routine: generate interleaved DC scan if possible, else N scans */
+{
+ int ci;
+
+ if (ncomps <= MAX_COMPS_IN_SCAN) {
+ /* Single interleaved DC scan */
+ scanptr->comps_in_scan = ncomps;
+ for (ci = 0; ci < ncomps; ci++)
+ scanptr->component_index[ci] = ci;
+ scanptr->Ss = scanptr->Se = 0;
+ scanptr->Ah = Ah;
+ scanptr->Al = Al;
+ scanptr++;
+ } else {
+ /* Noninterleaved DC scan for each component */
+ scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al);
+ }
+ return scanptr;
+}
+
+
+/*
+ * Create a recommended progressive-JPEG script.
+ * cinfo->num_components and cinfo->jpeg_color_space must be correct.
+ */
+
+GLOBAL(void)
+jpeg_simple_progression (j_compress_ptr cinfo)
+{
+ int ncomps = cinfo->num_components;
+ int nscans;
+ jpeg_scan_info * scanptr;
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ /* Figure space needed for script. Calculation must match code below! */
+ if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
+ /* Custom script for YCbCr color images. */
+ nscans = 10;
+ } else {
+ /* All-purpose script for other color spaces. */
+ if (ncomps > MAX_COMPS_IN_SCAN)
+ nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */
+ else
+ nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */
+ }
+
+ /* Allocate space for script.
+ * We need to put it in the permanent pool in case the application performs
+ * multiple compressions without changing the settings. To avoid a memory
+ * leak if jpeg_simple_progression is called repeatedly for the same JPEG
+ * object, we try to re-use previously allocated space, and we allocate
+ * enough space to handle YCbCr even if initially asked for grayscale.
+ */
+ if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) {
+ cinfo->script_space_size = MAX(nscans, 10);
+ cinfo->script_space = (jpeg_scan_info *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ cinfo->script_space_size * SIZEOF(jpeg_scan_info));
+ }
+ scanptr = cinfo->script_space;
+ cinfo->scan_info = scanptr;
+ cinfo->num_scans = nscans;
+
+ if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
+ /* Custom script for YCbCr color images. */
+ /* Initial DC scan */
+ scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
+ /* Initial AC scan: get some luma data out in a hurry */
+ scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2);
+ /* Chroma data is too small to be worth expending many scans on */
+ scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1);
+ scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1);
+ /* Complete spectral selection for luma AC */
+ scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2);
+ /* Refine next bit of luma AC */
+ scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1);
+ /* Finish DC successive approximation */
+ scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
+ /* Finish AC successive approximation */
+ scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0);
+ scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0);
+ /* Luma bottom bit comes last since it's usually largest scan */
+ scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0);
+ } else {
+ /* All-purpose script for other color spaces. */
+ /* Successive approximation first pass */
+ scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
+ scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2);
+ scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2);
+ /* Successive approximation second pass */
+ scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1);
+ /* Successive approximation final pass */
+ scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
+ scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0);
+ }
+}
+
+#endif /* C_PROGRESSIVE_SUPPORTED */
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+
+/*
+ * Create a single-entry lossless-JPEG script containing all components.
+ * cinfo->num_components must be correct.
+ */
+
+GLOBAL(void)
+jpeg_simple_lossless (j_compress_ptr cinfo, int predictor, int point_transform)
+{
+ int ncomps = cinfo->num_components;
+ int nscans = 1;
+ int ci;
+ jpeg_scan_info * scanptr;
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ cinfo->lossless = TRUE;
+
+ /* Set jpeg_color_space. */
+ jpeg_default_colorspace(cinfo);
+
+ /* Check to ensure that all components will fit in one scan. */
+ if (cinfo->num_components > MAX_COMPS_IN_SCAN)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
+ MAX_COMPS_IN_SCAN);
+
+ /* Allocate space for script.
+ * We need to put it in the permanent pool in case the application performs
+ * multiple compressions without changing the settings. To avoid a memory
+ * leak if jpeg_simple_lossless is called repeatedly for the same JPEG
+ * object, we try to re-use previously allocated space.
+ */
+ if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) {
+ cinfo->script_space_size = nscans;
+ cinfo->script_space = (jpeg_scan_info *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ cinfo->script_space_size * SIZEOF(jpeg_scan_info));
+ }
+ scanptr = cinfo->script_space;
+ cinfo->scan_info = scanptr;
+ cinfo->num_scans = nscans;
+
+ /* Fill the script. */
+ scanptr->comps_in_scan = ncomps;
+ for (ci = 0; ci < ncomps; ci++)
+ scanptr->component_index[ci] = ci;
+ scanptr->Ss = predictor;
+ scanptr->Se = 0;
+ scanptr->Ah = 0;
+ scanptr->Al = point_transform;
+}
+
+#endif /* C_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jcphuff.c
+ *
+ * Copyright (C) 1995-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy encoding routines for progressive JPEG.
+ *
+ * We do not support output suspension in this module, since the library
+ * currently does not allow multiple-scan files to be written with output
+ * suspension.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+#include "jchuff.h" /* Declarations shared with jc*huff.c */
+
+#ifdef C_PROGRESSIVE_SUPPORTED
+
+/* Expanded entropy encoder object for progressive Huffman encoding. */
+
+typedef struct {
+ /* Mode flag: TRUE for optimization, FALSE for actual data output */
+ boolean gather_statistics;
+
+ /* Bit-level coding status.
+ * next_output_byte/free_in_buffer are local copies of cinfo->dest fields.
+ */
+ JOCTET * next_output_byte; /* => next byte to write in buffer */
+ size_t free_in_buffer; /* # of byte spaces remaining in buffer */
+ INT32 put_buffer; /* current bit-accumulation buffer */
+ int put_bits; /* # of bits now in it */
+ j_compress_ptr cinfo; /* link to cinfo (needed for dump_buffer) */
+
+ /* Coding status for DC components */
+ int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
+
+ /* Coding status for AC components */
+ int ac_tbl_no; /* the table number of the single component */
+ unsigned int EOBRUN; /* run length of EOBs */
+ unsigned int BE; /* # of buffered correction bits before MCU */
+ char * bit_buffer; /* buffer for correction bits (1 per char) */
+ /* packing correction bits tightly would save some space but cost time... */
+
+ unsigned int restarts_to_go; /* MCUs left in this restart interval */
+ int next_restart_num; /* next restart number to write (0-7) */
+
+ /* Pointers to derived tables (these workspaces have image lifespan).
+ * Since any one scan codes only DC or only AC, we only need one set
+ * of tables, not one for DC and one for AC.
+ */
+ c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
+
+ /* Statistics tables for optimization; again, one set is enough */
+ long * count_ptrs[NUM_HUFF_TBLS];
+} phuff_entropy_encoder;
+
+typedef phuff_entropy_encoder * phuff_entropy_ptr;
+
+/* MAX_CORR_BITS is the number of bits the AC refinement correction-bit
+ * buffer can hold. Larger sizes may slightly improve compression, but
+ * 1000 is already well into the realm of overkill.
+ * The minimum safe size is 64 bits.
+ */
+
+#define MAX_CORR_BITS 1000 /* Max # of correction bits I can buffer */
+
+/* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.
+ * We assume that int right shift is unsigned if INT32 right shift is,
+ * which should be safe.
+ */
+
+#ifdef RIGHT_SHIFT_IS_UNSIGNED
+#define ISHIFT_TEMPS int ishift_temp;
+#define IRIGHT_SHIFT(x,shft) \
+ ((ishift_temp = (x)) < 0 ? \
+ (ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
+ (ishift_temp >> (shft)))
+#else
+#define ISHIFT_TEMPS
+#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
+#endif
+
+/* Forward declarations */
+METHODDEF(boolean) encode_mcu_DC_first JPP((j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(boolean) encode_mcu_AC_first JPP((j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(boolean) encode_mcu_DC_refine JPP((j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(boolean) encode_mcu_AC_refine JPP((j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(void) finish_pass_phuff JPP((j_compress_ptr cinfo));
+METHODDEF(void) finish_pass_gather_phuff JPP((j_compress_ptr cinfo));
+
+
+/*
+ * Initialize for a Huffman-compressed scan using progressive JPEG.
+ */
+
+METHODDEF(void)
+start_pass_phuff (j_compress_ptr cinfo, boolean gather_statistics)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+ boolean is_DC_band;
+ int ci, tbl;
+ jpeg_component_info * compptr;
+
+ entropy->cinfo = cinfo;
+ entropy->gather_statistics = gather_statistics;
+
+ is_DC_band = (cinfo->Ss == 0);
+
+ /* We assume jcmaster.c already validated the scan parameters. */
+
+ /* Select execution routines */
+ if (cinfo->Ah == 0) {
+ if (is_DC_band)
+ lossyc->entropy_encode_mcu = encode_mcu_DC_first;
+ else
+ lossyc->entropy_encode_mcu = encode_mcu_AC_first;
+ } else {
+ if (is_DC_band)
+ lossyc->entropy_encode_mcu = encode_mcu_DC_refine;
+ else {
+ lossyc->entropy_encode_mcu = encode_mcu_AC_refine;
+ /* AC refinement needs a correction bit buffer */
+ if (entropy->bit_buffer == NULL)
+ entropy->bit_buffer = (char *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ MAX_CORR_BITS * SIZEOF(char));
+ }
+ }
+ if (gather_statistics)
+ lossyc->pub.entropy_finish_pass = finish_pass_gather_phuff;
+ else
+ lossyc->pub.entropy_finish_pass = finish_pass_phuff;
+
+ /* Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1
+ * for AC coefficients.
+ */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* Initialize DC predictions to 0 */
+ entropy->last_dc_val[ci] = 0;
+ /* Get table index */
+ if (is_DC_band) {
+ if (cinfo->Ah != 0) /* DC refinement needs no table */
+ continue;
+ tbl = compptr->dc_tbl_no;
+ } else {
+ entropy->ac_tbl_no = tbl = compptr->ac_tbl_no;
+ }
+ if (gather_statistics) {
+ /* Check for invalid table index */
+ /* (make_c_derived_tbl does this in the other path) */
+ if (tbl < 0 || tbl >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);
+ /* Allocate and zero the statistics tables */
+ /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
+ if (entropy->count_ptrs[tbl] == NULL)
+ entropy->count_ptrs[tbl] = (long *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ 257 * SIZEOF(long));
+ MEMZERO(entropy->count_ptrs[tbl], 257 * SIZEOF(long));
+ } else {
+ /* Compute derived values for Huffman table */
+ /* We may do this more than once for a table, but it's not expensive */
+ jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl,
+ & entropy->derived_tbls[tbl]);
+ }
+ }
+
+ /* Initialize AC stuff */
+ entropy->EOBRUN = 0;
+ entropy->BE = 0;
+
+ /* Initialize bit buffer to empty */
+ entropy->put_buffer = 0;
+ entropy->put_bits = 0;
+
+ /* Initialize restart stuff */
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num = 0;
+}
+
+
+/* Outputting bytes to the file.
+ * NB: these must be called only when actually outputting,
+ * that is, entropy->gather_statistics == FALSE.
+ */
+
+/* Emit a byte */
+#define emit_byte(entropy,val) \
+ { *(entropy)->next_output_byte++ = (JOCTET) (val); \
+ if (--(entropy)->free_in_buffer == 0) \
+ dump_buffer(entropy); }
+
+
+LOCAL(void)
+dump_buffer (phuff_entropy_ptr entropy)
+/* Empty the output buffer; we do not support suspension in this module. */
+{
+ struct jpeg_destination_mgr * dest = entropy->cinfo->dest;
+
+ if (! (*dest->empty_output_buffer) (entropy->cinfo))
+ ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND);
+ /* After a successful buffer dump, must reset buffer pointers */
+ entropy->next_output_byte = dest->next_output_byte;
+ entropy->free_in_buffer = dest->free_in_buffer;
+}
+
+
+/* Outputting bits to the file */
+
+/* Only the right 24 bits of put_buffer are used; the valid bits are
+ * left-justified in this part. At most 16 bits can be passed to emit_bits
+ * in one call, and we never retain more than 7 bits in put_buffer
+ * between calls, so 24 bits are sufficient.
+ */
+
+INLINE
+LOCAL(void)
+emit_bits (phuff_entropy_ptr entropy, unsigned int code, int size)
+/* Emit some bits, unless we are in gather mode */
+{
+ /* This routine is heavily used, so it's worth coding tightly. */
+ register INT32 put_buffer = (INT32) code;
+ register int put_bits = entropy->put_bits;
+
+ /* if size is 0, caller used an invalid Huffman table entry */
+ if (size == 0)
+ ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
+
+ if (entropy->gather_statistics)
+ return; /* do nothing if we're only getting stats */
+
+ put_buffer &= (((INT32) 1)<<size) - 1; /* mask off any extra bits in code */
+
+ put_bits += size; /* new number of bits in buffer */
+
+ put_buffer <<= 24 - put_bits; /* align incoming bits */
+
+ put_buffer |= entropy->put_buffer; /* and merge with old buffer contents */
+
+ while (put_bits >= 8) {
+ int c = (int) ((put_buffer >> 16) & 0xFF);
+
+ emit_byte(entropy, c);
+ if (c == 0xFF) { /* need to stuff a zero byte? */
+ emit_byte(entropy, 0);
+ }
+ put_buffer <<= 8;
+ put_bits -= 8;
+ }
+
+ entropy->put_buffer = put_buffer; /* update variables */
+ entropy->put_bits = put_bits;
+}
+
+
+LOCAL(void)
+flush_bits (phuff_entropy_ptr entropy)
+{
+ emit_bits(entropy, 0x7F, 7); /* fill any partial byte with ones */
+ entropy->put_buffer = 0; /* and reset bit-buffer to empty */
+ entropy->put_bits = 0;
+}
+
+
+/*
+ * Emit (or just count) a Huffman symbol.
+ */
+
+INLINE
+LOCAL(void)
+emit_symbol (phuff_entropy_ptr entropy, int tbl_no, int symbol)
+{
+ if (entropy->gather_statistics)
+ entropy->count_ptrs[tbl_no][symbol]++;
+ else {
+ c_derived_tbl * tbl = entropy->derived_tbls[tbl_no];
+ emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
+ }
+}
+
+
+/*
+ * Emit bits from a correction bit buffer.
+ */
+
+LOCAL(void)
+emit_buffered_bits (phuff_entropy_ptr entropy, char * bufstart,
+ unsigned int nbits)
+{
+ if (entropy->gather_statistics)
+ return; /* no real work */
+
+ while (nbits > 0) {
+ emit_bits(entropy, (unsigned int) (*bufstart), 1);
+ bufstart++;
+ nbits--;
+ }
+}
+
+
+/*
+ * Emit any pending EOBRUN symbol.
+ */
+
+LOCAL(void)
+emit_eobrun (phuff_entropy_ptr entropy)
+{
+ register int temp, nbits;
+
+ if (entropy->EOBRUN > 0) { /* if there is any pending EOBRUN */
+ temp = entropy->EOBRUN;
+ nbits = 0;
+ while ((temp >>= 1))
+ nbits++;
+ /* safety check: shouldn't happen given limited correction-bit buffer */
+ if (nbits > 14)
+ ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
+
+ emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
+ if (nbits)
+ emit_bits(entropy, entropy->EOBRUN, nbits);
+
+ entropy->EOBRUN = 0;
+
+ /* Emit any buffered correction bits */
+ emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);
+ entropy->BE = 0;
+ }
+}
+
+
+/*
+ * Emit a restart marker & resynchronize predictions.
+ */
+
+LOCAL(void)
+emit_restart (phuff_entropy_ptr entropy, int restart_num)
+{
+ int ci;
+
+ emit_eobrun(entropy);
+
+ if (! entropy->gather_statistics) {
+ flush_bits(entropy);
+ emit_byte(entropy, 0xFF);
+ emit_byte(entropy, JPEG_RST0 + restart_num);
+ }
+
+ if (entropy->cinfo->Ss == 0) {
+ /* Re-initialize DC predictions to 0 */
+ for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++)
+ entropy->last_dc_val[ci] = 0;
+ } else {
+ /* Re-initialize all AC-related fields to 0 */
+ entropy->EOBRUN = 0;
+ entropy->BE = 0;
+ }
+}
+
+
+/*
+ * MCU encoding for DC initial scan (either spectral selection,
+ * or first pass of successive approximation).
+ */
+
+METHODDEF(boolean)
+encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+ register int temp, temp2;
+ register int nbits;
+ int blkn, ci;
+ int Al = cinfo->Al;
+ JBLOCKROW block;
+ jpeg_component_info * compptr;
+ ISHIFT_TEMPS
+
+ entropy->next_output_byte = cinfo->dest->next_output_byte;
+ entropy->free_in_buffer = cinfo->dest->free_in_buffer;
+
+ /* Emit restart marker if needed */
+ if (cinfo->restart_interval)
+ if (entropy->restarts_to_go == 0)
+ emit_restart(entropy, entropy->next_restart_num);
+
+ /* Encode the MCU data blocks */
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ block = MCU_data[blkn];
+ ci = cinfo->MCU_membership[blkn];
+ compptr = cinfo->cur_comp_info[ci];
+
+ /* Compute the DC value after the required point transform by Al.
+ * This is simply an arithmetic right shift.
+ */
+ temp2 = IRIGHT_SHIFT((int) ((*block)[0]), Al);
+
+ /* DC differences are figured on the point-transformed values. */
+ temp = temp2 - entropy->last_dc_val[ci];
+ entropy->last_dc_val[ci] = temp2;
+
+ /* Encode the DC coefficient difference per section G.1.2.1 */
+ temp2 = temp;
+ if (temp < 0) {
+ temp = -temp; /* temp is abs value of input */
+ /* For a negative input, want temp2 = bitwise complement of abs(input) */
+ /* This code assumes we are on a two's complement machine */
+ temp2--;
+ }
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ nbits = 0;
+ while (temp) {
+ nbits++;
+ temp >>= 1;
+ }
+ /* Check for out-of-range coefficient values.
+ * Since we're encoding a difference, the range limit is twice as much.
+ */
+ if (nbits > MAX_COEF_BITS+1)
+ ERREXIT(cinfo, JERR_BAD_DCT_COEF);
+
+ /* Count/emit the Huffman-coded symbol for the number of bits */
+ emit_symbol(entropy, compptr->dc_tbl_no, nbits);
+
+ /* Emit that number of bits of the value, if positive, */
+ /* or the complement of its magnitude, if negative. */
+ if (nbits) /* emit_bits rejects calls with size 0 */
+ emit_bits(entropy, (unsigned int) temp2, nbits);
+ }
+
+ cinfo->dest->next_output_byte = entropy->next_output_byte;
+ cinfo->dest->free_in_buffer = entropy->free_in_buffer;
+
+ /* Update restart-interval state too */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num++;
+ entropy->next_restart_num &= 7;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ return TRUE;
+}
+
+
+/*
+ * MCU encoding for AC initial scan (either spectral selection,
+ * or first pass of successive approximation).
+ */
+
+METHODDEF(boolean)
+encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+ register int temp, temp2;
+ register int nbits;
+ register int r, k;
+ int Se = cinfo->Se;
+ int Al = cinfo->Al;
+ JBLOCKROW block;
+
+ entropy->next_output_byte = cinfo->dest->next_output_byte;
+ entropy->free_in_buffer = cinfo->dest->free_in_buffer;
+
+ /* Emit restart marker if needed */
+ if (cinfo->restart_interval)
+ if (entropy->restarts_to_go == 0)
+ emit_restart(entropy, entropy->next_restart_num);
+
+ /* Encode the MCU data block */
+ block = MCU_data[0];
+
+ /* Encode the AC coefficients per section G.1.2.2, fig. G.3 */
+
+ r = 0; /* r = run length of zeros */
+
+ for (k = cinfo->Ss; k <= Se; k++) {
+ if ((temp = (*block)[jpeg_natural_order[k]]) == 0) {
+ r++;
+ continue;
+ }
+ /* We must apply the point transform by Al. For AC coefficients this
+ * is an integer division with rounding towards 0. To do this portably
+ * in C, we shift after obtaining the absolute value; so the code is
+ * interwoven with finding the abs value (temp) and output bits (temp2).
+ */
+ if (temp < 0) {
+ temp = -temp; /* temp is abs value of input */
+ temp >>= Al; /* apply the point transform */
+ /* For a negative coef, want temp2 = bitwise complement of abs(coef) */
+ temp2 = ~temp;
+ } else {
+ temp >>= Al; /* apply the point transform */
+ temp2 = temp;
+ }
+ /* Watch out for case that nonzero coef is zero after point transform */
+ if (temp == 0) {
+ r++;
+ continue;
+ }
+
+ /* Emit any pending EOBRUN */
+ if (entropy->EOBRUN > 0)
+ emit_eobrun(entropy);
+ /* if run length > 15, must emit special run-length-16 codes (0xF0) */
+ while (r > 15) {
+ emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
+ r -= 16;
+ }
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ nbits = 1; /* there must be at least one 1 bit */
+ while ((temp >>= 1))
+ nbits++;
+ /* Check for out-of-range coefficient values */
+ if (nbits > MAX_COEF_BITS)
+ ERREXIT(cinfo, JERR_BAD_DCT_COEF);
+
+ /* Count/emit Huffman symbol for run length / number of bits */
+ emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + nbits);
+
+ /* Emit that number of bits of the value, if positive, */
+ /* or the complement of its magnitude, if negative. */
+ emit_bits(entropy, (unsigned int) temp2, nbits);
+
+ r = 0; /* reset zero run length */
+ }
+
+ if (r > 0) { /* If there are trailing zeroes, */
+ entropy->EOBRUN++; /* count an EOB */
+ if (entropy->EOBRUN == 0x7FFF)
+ emit_eobrun(entropy); /* force it out to avoid overflow */
+ }
+
+ cinfo->dest->next_output_byte = entropy->next_output_byte;
+ cinfo->dest->free_in_buffer = entropy->free_in_buffer;
+
+ /* Update restart-interval state too */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num++;
+ entropy->next_restart_num &= 7;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ return TRUE;
+}
+
+
+/*
+ * MCU encoding for DC successive approximation refinement scan.
+ * Note: we assume such scans can be multi-component, although the spec
+ * is not very clear on the point.
+ */
+
+METHODDEF(boolean)
+encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+ register int temp;
+ int blkn;
+ int Al = cinfo->Al;
+ JBLOCKROW block;
+
+ entropy->next_output_byte = cinfo->dest->next_output_byte;
+ entropy->free_in_buffer = cinfo->dest->free_in_buffer;
+
+ /* Emit restart marker if needed */
+ if (cinfo->restart_interval)
+ if (entropy->restarts_to_go == 0)
+ emit_restart(entropy, entropy->next_restart_num);
+
+ /* Encode the MCU data blocks */
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ block = MCU_data[blkn];
+
+ /* We simply emit the Al'th bit of the DC coefficient value. */
+ temp = (*block)[0];
+ emit_bits(entropy, (unsigned int) (temp >> Al), 1);
+ }
+
+ cinfo->dest->next_output_byte = entropy->next_output_byte;
+ cinfo->dest->free_in_buffer = entropy->free_in_buffer;
+
+ /* Update restart-interval state too */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num++;
+ entropy->next_restart_num &= 7;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ return TRUE;
+}
+
+
+/*
+ * MCU encoding for AC successive approximation refinement scan.
+ */
+
+METHODDEF(boolean)
+encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+ register int temp;
+ register int r, k;
+ int EOB;
+ char *BR_buffer;
+ unsigned int BR;
+ int Se = cinfo->Se;
+ int Al = cinfo->Al;
+ JBLOCKROW block;
+ int absvalues[DCTSIZE2];
+
+ entropy->next_output_byte = cinfo->dest->next_output_byte;
+ entropy->free_in_buffer = cinfo->dest->free_in_buffer;
+
+ /* Emit restart marker if needed */
+ if (cinfo->restart_interval)
+ if (entropy->restarts_to_go == 0)
+ emit_restart(entropy, entropy->next_restart_num);
+
+ /* Encode the MCU data block */
+ block = MCU_data[0];
+
+ /* It is convenient to make a pre-pass to determine the transformed
+ * coefficients' absolute values and the EOB position.
+ */
+ EOB = 0;
+ for (k = cinfo->Ss; k <= Se; k++) {
+ temp = (*block)[jpeg_natural_order[k]];
+ /* We must apply the point transform by Al. For AC coefficients this
+ * is an integer division with rounding towards 0. To do this portably
+ * in C, we shift after obtaining the absolute value.
+ */
+ if (temp < 0)
+ temp = -temp; /* temp is abs value of input */
+ temp >>= Al; /* apply the point transform */
+ absvalues[k] = temp; /* save abs value for main pass */
+ if (temp == 1)
+ EOB = k; /* EOB = index of last newly-nonzero coef */
+ }
+
+ /* Encode the AC coefficients per section G.1.2.3, fig. G.7 */
+
+ r = 0; /* r = run length of zeros */
+ BR = 0; /* BR = count of buffered bits added now */
+ BR_buffer = entropy->bit_buffer + entropy->BE; /* Append bits to buffer */
+
+ for (k = cinfo->Ss; k <= Se; k++) {
+ if ((temp = absvalues[k]) == 0) {
+ r++;
+ continue;
+ }
+
+ /* Emit any required ZRLs, but not if they can be folded into EOB */
+ while (r > 15 && k <= EOB) {
+ /* emit any pending EOBRUN and the BE correction bits */
+ emit_eobrun(entropy);
+ /* Emit ZRL */
+ emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
+ r -= 16;
+ /* Emit buffered correction bits that must be associated with ZRL */
+ emit_buffered_bits(entropy, BR_buffer, BR);
+ BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
+ BR = 0;
+ }
+
+ /* If the coef was previously nonzero, it only needs a correction bit.
+ * NOTE: a straight translation of the spec's figure G.7 would suggest
+ * that we also need to test r > 15. But if r > 15, we can only get here
+ * if k > EOB, which implies that this coefficient is not 1.
+ */
+ if (temp > 1) {
+ /* The correction bit is the next bit of the absolute value. */
+ BR_buffer[BR++] = (char) (temp & 1);
+ continue;
+ }
+
+ /* Emit any pending EOBRUN and the BE correction bits */
+ emit_eobrun(entropy);
+
+ /* Count/emit Huffman symbol for run length / number of bits */
+ emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1);
+
+ /* Emit output bit for newly-nonzero coef */
+ temp = ((*block)[jpeg_natural_order[k]] < 0) ? 0 : 1;
+ emit_bits(entropy, (unsigned int) temp, 1);
+
+ /* Emit buffered correction bits that must be associated with this code */
+ emit_buffered_bits(entropy, BR_buffer, BR);
+ BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
+ BR = 0;
+ r = 0; /* reset zero run length */
+ }
+
+ if (r > 0 || BR > 0) { /* If there are trailing zeroes, */
+ entropy->EOBRUN++; /* count an EOB */
+ entropy->BE += BR; /* concat my correction bits to older ones */
+ /* We force out the EOB if we risk either:
+ * 1. overflow of the EOB counter;
+ * 2. overflow of the correction bit buffer during the next MCU.
+ */
+ if (entropy->EOBRUN == 0x7FFF || entropy->BE > (MAX_CORR_BITS-DCTSIZE2+1))
+ emit_eobrun(entropy);
+ }
+
+ cinfo->dest->next_output_byte = entropy->next_output_byte;
+ cinfo->dest->free_in_buffer = entropy->free_in_buffer;
+
+ /* Update restart-interval state too */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num++;
+ entropy->next_restart_num &= 7;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ return TRUE;
+}
+
+
+/*
+ * Finish up at the end of a Huffman-compressed progressive scan.
+ */
+
+METHODDEF(void)
+finish_pass_phuff (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+
+ entropy->next_output_byte = cinfo->dest->next_output_byte;
+ entropy->free_in_buffer = cinfo->dest->free_in_buffer;
+
+ /* Flush out any buffered data */
+ emit_eobrun(entropy);
+ flush_bits(entropy);
+
+ cinfo->dest->next_output_byte = entropy->next_output_byte;
+ cinfo->dest->free_in_buffer = entropy->free_in_buffer;
+}
+
+
+/*
+ * Finish up a statistics-gathering pass and create the new Huffman tables.
+ */
+
+METHODDEF(void)
+finish_pass_gather_phuff (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyc->entropy_private;
+ boolean is_DC_band;
+ int ci, tbl;
+ jpeg_component_info * compptr;
+ JHUFF_TBL **htblptr;
+ boolean did[NUM_HUFF_TBLS];
+
+ /* Flush out buffered data (all we care about is counting the EOB symbol) */
+ emit_eobrun(entropy);
+
+ is_DC_band = (cinfo->Ss == 0);
+
+ /* It's important not to apply jpeg_gen_optimal_table more than once
+ * per table, because it clobbers the input frequency counts!
+ */
+ MEMZERO(did, SIZEOF(did));
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ if (is_DC_band) {
+ if (cinfo->Ah != 0) /* DC refinement needs no table */
+ continue;
+ tbl = compptr->dc_tbl_no;
+ } else {
+ tbl = compptr->ac_tbl_no;
+ }
+ if (! did[tbl]) {
+ if (is_DC_band)
+ htblptr = & cinfo->dc_huff_tbl_ptrs[tbl];
+ else
+ htblptr = & cinfo->ac_huff_tbl_ptrs[tbl];
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+ jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[tbl]);
+ did[tbl] = TRUE;
+ }
+ }
+}
+
+
+METHODDEF(boolean)
+need_optimization_pass (j_compress_ptr cinfo)
+{
+ return (cinfo->Ss != 0 || cinfo->Ah == 0);
+}
+
+
+/*
+ * Module initialization routine for progressive Huffman entropy encoding.
+ */
+
+GLOBAL(void)
+jinit_phuff_encoder (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy;
+ int i;
+
+ entropy = (phuff_entropy_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(phuff_entropy_encoder));
+ lossyc->entropy_private = (struct jpeg_entropy_encoder *) entropy;
+ lossyc->pub.entropy_start_pass = start_pass_phuff;
+ lossyc->pub.need_optimization_pass = need_optimization_pass;
+
+ /* Mark tables unallocated */
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ entropy->derived_tbls[i] = NULL;
+ entropy->count_ptrs[i] = NULL;
+ }
+ entropy->bit_buffer = NULL; /* needed only in AC refinement scan */
+}
+
+#endif /* C_PROGRESSIVE_SUPPORTED */
--- /dev/null
+/*
+ * jcpred.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains sample differencing for lossless JPEG.
+ *
+ * In order to avoid paying the performance penalty of having to check the
+ * predictor being used and the row being processed for each call of the
+ * undifferencer, and to promote optimization, we have separate differencing
+ * functions for each case.
+ *
+ * We are able to avoid duplicating source code by implementing the predictors
+ * and differencers as macros. Each of the differencing functions are
+ * simply wrappers around a DIFFERENCE macro with the appropriate PREDICTOR
+ * macro passed as an argument.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+
+/* Private predictor object */
+
+typedef struct {
+ /* MCU-rows left in the restart interval for each component */
+ unsigned int restart_rows_to_go[MAX_COMPONENTS];
+} c_predictor;
+
+typedef c_predictor * c_pred_ptr;
+
+/* Forward declarations */
+LOCAL(void) reset_predictor
+ JPP((j_compress_ptr cinfo, int ci));
+METHODDEF(void) start_pass
+ JPP((j_compress_ptr cinfo));
+
+
+/* Predictor for the first column of the first row: 2^(P-Pt-1) */
+#define INITIAL_PREDICTORx (1 << (cinfo->data_precision - cinfo->Al - 1))
+
+/* Predictor for the first column of the remaining rows: Rb */
+#define INITIAL_PREDICTOR2 GETJSAMPLE(prev_row[0])
+
+
+/*
+ * 1-Dimensional differencer routine.
+ *
+ * This macro implements the 1-D horizontal predictor (1). INITIAL_PREDICTOR
+ * is used as the special case predictor for the first column, which must be
+ * either INITIAL_PREDICTOR2 or INITIAL_PREDICTORx. The remaining samples
+ * use PREDICTOR1.
+ */
+
+#define DIFFERENCE_1D(INITIAL_PREDICTOR) \
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec; \
+ c_pred_ptr pred = (c_pred_ptr) losslsc->pred_private; \
+ boolean restart = FALSE; \
+ unsigned int xindex; \
+ int samp, Ra; \
+ \
+ samp = GETJSAMPLE(input_buf[0]); \
+ diff_buf[0] = samp - INITIAL_PREDICTOR; \
+ \
+ for (xindex = 1; xindex < width; xindex++) { \
+ Ra = samp; \
+ samp = GETJSAMPLE(input_buf[xindex]); \
+ diff_buf[xindex] = samp - PREDICTOR1; \
+ } \
+ \
+ /* Account for restart interval (no-op if not using restarts) */ \
+ if (cinfo->restart_interval) { \
+ if (--(pred->restart_rows_to_go[ci]) == 0) { \
+ reset_predictor(cinfo, ci); \
+ restart = TRUE; \
+ } \
+ }
+
+
+/*
+ * 2-Dimensional differencer routine.
+ *
+ * This macro implements the 2-D horizontal predictors (#2-7). PREDICTOR2 is
+ * used as the special case predictor for the first column. The remaining
+ * samples use PREDICTOR, which is a function of Ra, Rb, Rc.
+ *
+ * Because prev_row and output_buf may point to the same storage area (in an
+ * interleaved image with Vi=1, for example), we must take care to buffer Rb/Rc
+ * before writing the current reconstructed sample value into output_buf.
+ */
+
+#define DIFFERENCE_2D(PREDICTOR) \
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec; \
+ c_pred_ptr pred = (c_pred_ptr) losslsc->pred_private; \
+ unsigned int xindex; \
+ int samp, Ra, Rb, Rc; \
+ \
+ Rb = GETJSAMPLE(prev_row[0]); \
+ samp = GETJSAMPLE(input_buf[0]); \
+ diff_buf[0] = samp - PREDICTOR2; \
+ \
+ for (xindex = 1; xindex < width; xindex++) { \
+ Rc = Rb; \
+ Rb = GETJSAMPLE(prev_row[xindex]); \
+ Ra = samp; \
+ samp = GETJSAMPLE(input_buf[xindex]); \
+ diff_buf[xindex] = samp - PREDICTOR; \
+ } \
+ \
+ /* Account for restart interval (no-op if not using restarts) */ \
+ if (cinfo->restart_interval) { \
+ if (--pred->restart_rows_to_go[ci] == 0) \
+ reset_predictor(cinfo, ci); \
+ }
+
+
+/*
+ * Differencers for the all rows but the first in a scan or restart interval.
+ * The first sample in the row is differenced using the vertical
+ * predictor (2). The rest of the samples are differenced using the
+ * predictor specified in the scan header.
+ */
+
+METHODDEF(void)
+jpeg_difference1(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ DIFFERENCE_1D(INITIAL_PREDICTOR2);
+}
+
+METHODDEF(void)
+jpeg_difference2(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ DIFFERENCE_2D(PREDICTOR2);
+}
+
+METHODDEF(void)
+jpeg_difference3(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ DIFFERENCE_2D(PREDICTOR3);
+}
+
+METHODDEF(void)
+jpeg_difference4(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ DIFFERENCE_2D(PREDICTOR4);
+}
+
+METHODDEF(void)
+jpeg_difference5(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ SHIFT_TEMPS
+ DIFFERENCE_2D(PREDICTOR5);
+}
+
+METHODDEF(void)
+jpeg_difference6(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ SHIFT_TEMPS
+ DIFFERENCE_2D(PREDICTOR6);
+}
+
+METHODDEF(void)
+jpeg_difference7(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ SHIFT_TEMPS
+ DIFFERENCE_2D(PREDICTOR7);
+}
+
+
+/*
+ * Differencer for the first row in a scan or restart interval. The first
+ * sample in the row is differenced using the special predictor constant
+ * x=2^(P-Pt-1). The rest of the samples are differenced using the
+ * 1-D horizontal predictor (1).
+ */
+
+METHODDEF(void)
+jpeg_difference_first_row(j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width)
+{
+ DIFFERENCE_1D(INITIAL_PREDICTORx);
+ (void)prev_row;
+
+ /*
+ * Now that we have differenced the first row, we want to use the
+ * differencer which corresponds to the predictor specified in the
+ * scan header.
+ *
+ * Note that we don't to do this if we have just reset the predictor
+ * for a new restart interval.
+ */
+ if (!restart) {
+ switch (cinfo->Ss) {
+ case 1:
+ losslsc->predict_difference[ci] = jpeg_difference1;
+ break;
+ case 2:
+ losslsc->predict_difference[ci] = jpeg_difference2;
+ break;
+ case 3:
+ losslsc->predict_difference[ci] = jpeg_difference3;
+ break;
+ case 4:
+ losslsc->predict_difference[ci] = jpeg_difference4;
+ break;
+ case 5:
+ losslsc->predict_difference[ci] = jpeg_difference5;
+ break;
+ case 6:
+ losslsc->predict_difference[ci] = jpeg_difference6;
+ break;
+ case 7:
+ losslsc->predict_difference[ci] = jpeg_difference7;
+ break;
+ }
+ }
+}
+
+/*
+ * Reset predictor at the start of a pass or restart interval.
+ */
+
+LOCAL(void)
+reset_predictor (j_compress_ptr cinfo, int ci)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_pred_ptr pred = (c_pred_ptr) losslsc->pred_private;
+
+ /* Initialize restart counter */
+ pred->restart_rows_to_go[ci] =
+ cinfo->restart_interval / cinfo->MCUs_per_row;
+
+ /* Set difference function to first row function */
+ losslsc->predict_difference[ci] = jpeg_difference_first_row;
+}
+
+
+/*
+ * Initialize for an input processing pass.
+ */
+
+METHODDEF(void)
+start_pass (j_compress_ptr cinfo)
+{
+ /* j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec; */
+ /* c_pred_ptr pred = (c_pred_ptr) losslsc->pred_private; */
+ int ci;
+
+ /* Check that the restart interval is an integer multiple of the number
+ * of MCU in an MCU-row.
+ */
+ if (cinfo->restart_interval % cinfo->MCUs_per_row != 0)
+ ERREXIT2(cinfo, JERR_BAD_RESTART,
+ cinfo->restart_interval, cinfo->MCUs_per_row);
+
+ /* Set predictors for start of pass */
+ for (ci = 0; ci < cinfo->num_components; ci++)
+ reset_predictor(cinfo, ci);
+}
+
+
+/*
+ * Module initialization routine for the differencer.
+ */
+
+GLOBAL(void)
+jinit_differencer (j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+ c_pred_ptr pred;
+
+ pred = (c_pred_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(c_predictor));
+ losslsc->pred_private = (void *) pred;
+ losslsc->predict_start_pass = start_pass;
+}
+
+#endif /* C_LOSSLESS_SUPPORTED */
+
--- /dev/null
+/*
+ * jcprepct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the compression preprocessing controller.
+ * This controller manages the color conversion, downsampling,
+ * and edge expansion steps.
+ *
+ * Most of the complexity here is associated with buffering input rows
+ * as required by the downsampler. See the comments at the head of
+ * jcsample.c for the downsampler's needs.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* At present, jcsample.c can request context rows only for smoothing.
+ * In the future, we might also need context rows for CCIR601 sampling
+ * or other more-complex downsampling procedures. The code to support
+ * context rows should be compiled only if needed.
+ */
+#ifdef INPUT_SMOOTHING_SUPPORTED
+#define CONTEXT_ROWS_SUPPORTED
+#endif
+
+
+/*
+ * For the simple (no-context-row) case, we just need to buffer one
+ * row group's worth of pixels for the downsampling step. At the bottom of
+ * the image, we pad to a full row group by replicating the last pixel row.
+ * The downsampler's last output row is then replicated if needed to pad
+ * out to a full iMCU row.
+ *
+ * When providing context rows, we must buffer three row groups' worth of
+ * pixels. Three row groups are physically allocated, but the row pointer
+ * arrays are made five row groups high, with the extra pointers above and
+ * below "wrapping around" to point to the last and first real row groups.
+ * This allows the downsampler to access the proper context rows.
+ * At the top and bottom of the image, we create dummy context rows by
+ * copying the first or last real pixel row. This copying could be avoided
+ * by pointer hacking as is done in jdmainct.c, but it doesn't seem worth the
+ * trouble on the compression side.
+ */
+
+
+/* Private buffer controller object */
+
+typedef struct {
+ struct jpeg_c_prep_controller pub; /* public fields */
+
+ /* Downsampling input buffer. This buffer holds color-converted data
+ * until we have enough to do a downsample step.
+ */
+ JSAMPARRAY color_buf[MAX_COMPONENTS];
+
+ JDIMENSION rows_to_go; /* counts rows remaining in source image */
+ int next_buf_row; /* index of next row to store in color_buf */
+
+#ifdef CONTEXT_ROWS_SUPPORTED /* only needed for context case */
+ int this_row_group; /* starting row index of group to process */
+ int next_buf_stop; /* downsample when we reach this index */
+#endif
+} my_prep_controller;
+
+typedef my_prep_controller * my_prep_ptr;
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_prep (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ my_prep_ptr prep = (my_prep_ptr) cinfo->prep;
+
+ if (pass_mode != JBUF_PASS_THRU)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+
+ /* Initialize total-height counter for detecting bottom of image */
+ prep->rows_to_go = cinfo->image_height;
+ /* Mark the conversion buffer empty */
+ prep->next_buf_row = 0;
+#ifdef CONTEXT_ROWS_SUPPORTED
+ /* Preset additional state variables for context mode.
+ * These aren't used in non-context mode, so we needn't test which mode.
+ */
+ prep->this_row_group = 0;
+ /* Set next_buf_stop to stop after two row groups have been read in. */
+ prep->next_buf_stop = 2 * cinfo->max_v_samp_factor;
+#endif
+}
+
+
+/*
+ * Expand an image vertically from height input_rows to height output_rows,
+ * by duplicating the bottom row.
+ */
+
+LOCAL(void)
+expand_bottom_edge (JSAMPARRAY image_data, JDIMENSION num_cols,
+ int input_rows, int output_rows)
+{
+ register int row;
+
+ for (row = input_rows; row < output_rows; row++) {
+ jcopy_sample_rows(image_data, input_rows-1, image_data, row,
+ 1, num_cols);
+ }
+}
+
+
+/*
+ * Process some data in the simple no-context case.
+ *
+ * Preprocessor output data is counted in "row groups". A row group
+ * is defined to be v_samp_factor sample rows of each component.
+ * Downsampling will produce this much data from each max_v_samp_factor
+ * input rows.
+ */
+
+METHODDEF(void)
+pre_process_data (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail,
+ JSAMPIMAGE output_buf, JDIMENSION *out_row_group_ctr,
+ JDIMENSION out_row_groups_avail)
+{
+ my_prep_ptr prep = (my_prep_ptr) cinfo->prep;
+ int numrows, ci;
+ JDIMENSION inrows;
+ jpeg_component_info * compptr;
+
+ while (*in_row_ctr < in_rows_avail &&
+ *out_row_group_ctr < out_row_groups_avail) {
+ /* Do color conversion to fill the conversion buffer. */
+ inrows = in_rows_avail - *in_row_ctr;
+ numrows = cinfo->max_v_samp_factor - prep->next_buf_row;
+ numrows = (int) MIN((JDIMENSION) numrows, inrows);
+ (*cinfo->cconvert->color_convert) (cinfo, input_buf + *in_row_ctr,
+ prep->color_buf,
+ (JDIMENSION) prep->next_buf_row,
+ numrows);
+ *in_row_ctr += numrows;
+ prep->next_buf_row += numrows;
+ prep->rows_to_go -= numrows;
+ /* If at bottom of image, pad to fill the conversion buffer. */
+ if (prep->rows_to_go == 0 &&
+ prep->next_buf_row < cinfo->max_v_samp_factor) {
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ expand_bottom_edge(prep->color_buf[ci], cinfo->image_width,
+ prep->next_buf_row, cinfo->max_v_samp_factor);
+ }
+ prep->next_buf_row = cinfo->max_v_samp_factor;
+ }
+ /* If we've filled the conversion buffer, empty it. */
+ if (prep->next_buf_row == cinfo->max_v_samp_factor) {
+ (*cinfo->downsample->downsample) (cinfo,
+ prep->color_buf, (JDIMENSION) 0,
+ output_buf, *out_row_group_ctr);
+ prep->next_buf_row = 0;
+ (*out_row_group_ctr)++;
+ }
+ /* If at bottom of image, pad the output to a full iMCU height.
+ * Note we assume the caller is providing a one-iMCU-height output buffer!
+ */
+ if (prep->rows_to_go == 0 &&
+ *out_row_group_ctr < out_row_groups_avail) {
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ expand_bottom_edge(output_buf[ci],
+ compptr->width_in_data_units * cinfo->data_unit,
+ (int) (*out_row_group_ctr * compptr->v_samp_factor),
+ (int) (out_row_groups_avail * compptr->v_samp_factor));
+ }
+ *out_row_group_ctr = out_row_groups_avail;
+ break; /* can exit outer loop without test */
+ }
+ }
+}
+
+
+#ifdef CONTEXT_ROWS_SUPPORTED
+
+/*
+ * Process some data in the context case.
+ */
+
+METHODDEF(void)
+pre_process_context (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail,
+ JSAMPIMAGE output_buf, JDIMENSION *out_row_group_ctr,
+ JDIMENSION out_row_groups_avail)
+{
+ my_prep_ptr prep = (my_prep_ptr) cinfo->prep;
+ int numrows, ci;
+ int buf_height = cinfo->max_v_samp_factor * 3;
+ JDIMENSION inrows;
+
+ while (*out_row_group_ctr < out_row_groups_avail) {
+ if (*in_row_ctr < in_rows_avail) {
+ /* Do color conversion to fill the conversion buffer. */
+ inrows = in_rows_avail - *in_row_ctr;
+ numrows = prep->next_buf_stop - prep->next_buf_row;
+ numrows = (int) MIN((JDIMENSION) numrows, inrows);
+ (*cinfo->cconvert->color_convert) (cinfo, input_buf + *in_row_ctr,
+ prep->color_buf,
+ (JDIMENSION) prep->next_buf_row,
+ numrows);
+ /* Pad at top of image, if first time through */
+ if (prep->rows_to_go == cinfo->image_height) {
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ int row;
+ for (row = 1; row <= cinfo->max_v_samp_factor; row++) {
+ jcopy_sample_rows(prep->color_buf[ci], 0,
+ prep->color_buf[ci], -row,
+ 1, cinfo->image_width);
+ }
+ }
+ }
+ *in_row_ctr += numrows;
+ prep->next_buf_row += numrows;
+ prep->rows_to_go -= numrows;
+ } else {
+ /* Return for more data, unless we are at the bottom of the image. */
+ if (prep->rows_to_go != 0)
+ break;
+ /* When at bottom of image, pad to fill the conversion buffer. */
+ if (prep->next_buf_row < prep->next_buf_stop) {
+ for (ci = 0; ci < cinfo->num_components; ci++) {
+ expand_bottom_edge(prep->color_buf[ci], cinfo->image_width,
+ prep->next_buf_row, prep->next_buf_stop);
+ }
+ prep->next_buf_row = prep->next_buf_stop;
+ }
+ }
+ /* If we've gotten enough data, downsample a row group. */
+ if (prep->next_buf_row == prep->next_buf_stop) {
+ (*cinfo->downsample->downsample) (cinfo,
+ prep->color_buf,
+ (JDIMENSION) prep->this_row_group,
+ output_buf, *out_row_group_ctr);
+ (*out_row_group_ctr)++;
+ /* Advance pointers with wraparound as necessary. */
+ prep->this_row_group += cinfo->max_v_samp_factor;
+ if (prep->this_row_group >= buf_height)
+ prep->this_row_group = 0;
+ if (prep->next_buf_row >= buf_height)
+ prep->next_buf_row = 0;
+ prep->next_buf_stop = prep->next_buf_row + cinfo->max_v_samp_factor;
+ }
+ }
+}
+
+
+/*
+ * Create the wrapped-around downsampling input buffer needed for context mode.
+ */
+
+LOCAL(void)
+create_context_buffer (j_compress_ptr cinfo)
+{
+ my_prep_ptr prep = (my_prep_ptr) cinfo->prep;
+ int rgroup_height = cinfo->max_v_samp_factor;
+ int ci, i;
+ jpeg_component_info * compptr;
+ JSAMPARRAY true_buffer, fake_buffer;
+
+ /* Grab enough space for fake row pointers for all the components;
+ * we need five row groups' worth of pointers for each component.
+ */
+ fake_buffer = (JSAMPARRAY)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (cinfo->num_components * 5 * rgroup_height) *
+ SIZEOF(JSAMPROW));
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Allocate the actual buffer space (3 row groups) for this component.
+ * We make the buffer wide enough to allow the downsampler to edge-expand
+ * horizontally within the buffer, if it so chooses.
+ */
+ true_buffer = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) (((long) compptr->width_in_data_units * cinfo->data_unit *
+ cinfo->max_h_samp_factor) / compptr->h_samp_factor),
+ (JDIMENSION) (3 * rgroup_height));
+ /* Copy true buffer row pointers into the middle of the fake row array */
+ MEMCOPY(fake_buffer + rgroup_height, true_buffer,
+ 3 * rgroup_height * SIZEOF(JSAMPROW));
+ /* Fill in the above and below wraparound pointers */
+ for (i = 0; i < rgroup_height; i++) {
+ fake_buffer[i] = true_buffer[2 * rgroup_height + i];
+ fake_buffer[4 * rgroup_height + i] = true_buffer[i];
+ }
+ prep->color_buf[ci] = fake_buffer + rgroup_height;
+ fake_buffer += 5 * rgroup_height; /* point to space for next component */
+ }
+}
+
+#endif /* CONTEXT_ROWS_SUPPORTED */
+
+
+/*
+ * Initialize preprocessing controller.
+ */
+
+GLOBAL(void)
+jinit_c_prep_controller (j_compress_ptr cinfo, boolean need_full_buffer)
+{
+ my_prep_ptr prep;
+ int ci;
+ jpeg_component_info * compptr;
+
+ if (need_full_buffer) /* safety check */
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+
+ prep = (my_prep_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_prep_controller));
+ cinfo->prep = (struct jpeg_c_prep_controller *) prep;
+ prep->pub.start_pass = start_pass_prep;
+
+ /* Allocate the color conversion buffer.
+ * We make the buffer wide enough to allow the downsampler to edge-expand
+ * horizontally within the buffer, if it so chooses.
+ */
+ if (cinfo->downsample->need_context_rows) {
+ /* Set up to provide context rows */
+#ifdef CONTEXT_ROWS_SUPPORTED
+ prep->pub.pre_process_data = pre_process_context;
+ create_context_buffer(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ /* No context, just make it tall enough for one row group */
+ prep->pub.pre_process_data = pre_process_data;
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ prep->color_buf[ci] = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) (((long) compptr->width_in_data_units * cinfo->data_unit *
+ cinfo->max_h_samp_factor) / compptr->h_samp_factor),
+ (JDIMENSION) cinfo->max_v_samp_factor);
+ }
+ }
+}
--- /dev/null
+/*
+ * jcsample.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains downsampling routines.
+ *
+ * Downsampling input data is counted in "row groups". A row group
+ * is defined to be max_v_samp_factor pixel rows of each component,
+ * from which the downsampler produces v_samp_factor sample rows.
+ * A single row group is processed in each call to the downsampler module.
+ *
+ * The downsampler is responsible for edge-expansion of its output data
+ * to fill an integral number of DCT blocks horizontally. The source buffer
+ * may be modified if it is helpful for this purpose (the source buffer is
+ * allocated wide enough to correspond to the desired output width).
+ * The caller (the prep controller) is responsible for vertical padding.
+ *
+ * The downsampler may request "context rows" by setting need_context_rows
+ * during startup. In this case, the input arrays will contain at least
+ * one row group's worth of pixels above and below the passed-in data;
+ * the caller will create dummy rows at image top and bottom by replicating
+ * the first or last real pixel row.
+ *
+ * An excellent reference for image resampling is
+ * Digital Image Warping, George Wolberg, 1990.
+ * Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
+ *
+ * The downsampling algorithm used here is a simple average of the source
+ * pixels covered by the output pixel. The hi-falutin sampling literature
+ * refers to this as a "box filter". In general the characteristics of a box
+ * filter are not very good, but for the specific cases we normally use (1:1
+ * and 2:1 ratios) the box is equivalent to a "triangle filter" which is not
+ * nearly so bad. If you intend to use other sampling ratios, you'd be well
+ * advised to improve this code.
+ *
+ * A simple input-smoothing capability is provided. This is mainly intended
+ * for cleaning up color-dithered GIF input files (if you find it inadequate,
+ * we suggest using an external filtering program such as pnmconvol). When
+ * enabled, each input pixel P is replaced by a weighted sum of itself and its
+ * eight neighbors. P's weight is 1-8*SF and each neighbor's weight is SF,
+ * where SF = (smoothing_factor / 1024).
+ * Currently, smoothing is only supported for 2h2v sampling factors.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Pointer to routine to downsample a single component */
+typedef JMETHOD(void, downsample1_ptr,
+ (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data));
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_downsampler pub; /* public fields */
+
+ /* Downsampling method pointers, one per component */
+ downsample1_ptr methods[MAX_COMPONENTS];
+} my_downsampler;
+
+typedef my_downsampler * my_downsample_ptr;
+
+
+/*
+ * Initialize for a downsampling pass.
+ */
+
+METHODDEF(void)
+start_pass_downsample (j_compress_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work for now */
+}
+
+
+/*
+ * Expand a component horizontally from width input_cols to width output_cols,
+ * by duplicating the rightmost samples.
+ */
+
+LOCAL(void)
+expand_right_edge (JSAMPARRAY image_data, int num_rows,
+ JDIMENSION input_cols, JDIMENSION output_cols)
+{
+ register JSAMPROW ptr;
+ register JSAMPLE pixval;
+ register int count;
+ int row;
+ int numcols = (int) (output_cols - input_cols);
+
+ if (numcols > 0) {
+ for (row = 0; row < num_rows; row++) {
+ ptr = image_data[row] + input_cols;
+ pixval = ptr[-1]; /* don't need GETJSAMPLE() here */
+ for (count = numcols; count > 0; count--)
+ *ptr++ = pixval;
+ }
+ }
+}
+
+
+/*
+ * Do downsampling for a whole row group (all components).
+ *
+ * In this version we simply downsample each component independently.
+ */
+
+METHODDEF(void)
+sep_downsample (j_compress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION in_row_index,
+ JSAMPIMAGE output_buf, JDIMENSION out_row_group_index)
+{
+ my_downsample_ptr downsample = (my_downsample_ptr) cinfo->downsample;
+ int ci;
+ jpeg_component_info * compptr;
+ JSAMPARRAY in_ptr, out_ptr;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ in_ptr = input_buf[ci] + in_row_index;
+ out_ptr = output_buf[ci] + (out_row_group_index * compptr->v_samp_factor);
+ (*downsample->methods[ci]) (cinfo, compptr, in_ptr, out_ptr);
+ }
+}
+
+
+/*
+ * Downsample pixel values of a single component.
+ * One row group is processed per call.
+ * This version handles arbitrary integral sampling ratios, without smoothing.
+ * Note that this version is not actually used for customary sampling ratios.
+ */
+
+METHODDEF(void)
+int_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data)
+{
+ int inrow, outrow, h_expand, v_expand, numpix, numpix2, h, v;
+ JDIMENSION outcol, outcol_h; /* outcol_h == outcol*h_expand */
+ JDIMENSION output_cols = compptr->width_in_data_units * cinfo->data_unit;
+ JSAMPROW inptr, outptr;
+ INT32 outvalue;
+
+ h_expand = cinfo->max_h_samp_factor / compptr->h_samp_factor;
+ v_expand = cinfo->max_v_samp_factor / compptr->v_samp_factor;
+ numpix = h_expand * v_expand;
+ numpix2 = numpix/2;
+
+ /* Expand input data enough to let all the output samples be generated
+ * by the standard loop. Special-casing padded output would be more
+ * efficient.
+ */
+ expand_right_edge(input_data, cinfo->max_v_samp_factor,
+ cinfo->image_width, output_cols * h_expand);
+
+ inrow = 0;
+ for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
+ outptr = output_data[outrow];
+ for (outcol = 0, outcol_h = 0; outcol < output_cols;
+ outcol++, outcol_h += h_expand) {
+ outvalue = 0;
+ for (v = 0; v < v_expand; v++) {
+ inptr = input_data[inrow+v] + outcol_h;
+ for (h = 0; h < h_expand; h++) {
+ outvalue += (INT32) GETJSAMPLE(*inptr++);
+ }
+ }
+ *outptr++ = (JSAMPLE) ((outvalue + numpix2) / numpix);
+ }
+ inrow += v_expand;
+ }
+}
+
+
+/*
+ * Downsample pixel values of a single component.
+ * This version handles the special case of a full-size component,
+ * without smoothing.
+ */
+
+METHODDEF(void)
+fullsize_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data)
+{
+ /* Copy the data */
+ jcopy_sample_rows(input_data, 0, output_data, 0,
+ cinfo->max_v_samp_factor, cinfo->image_width);
+ /* Edge-expand */
+ expand_right_edge(output_data, cinfo->max_v_samp_factor,
+ cinfo->image_width, compptr->width_in_data_units * cinfo->data_unit);
+}
+
+
+/*
+ * Downsample pixel values of a single component.
+ * This version handles the common case of 2:1 horizontal and 1:1 vertical,
+ * without smoothing.
+ *
+ * A note about the "bias" calculations: when rounding fractional values to
+ * integer, we do not want to always round 0.5 up to the next integer.
+ * If we did that, we'd introduce a noticeable bias towards larger values.
+ * Instead, this code is arranged so that 0.5 will be rounded up or down at
+ * alternate pixel locations (a simple ordered dither pattern).
+ */
+
+METHODDEF(void)
+h2v1_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data)
+{
+ int outrow;
+ JDIMENSION outcol;
+ JDIMENSION output_cols = compptr->width_in_data_units * cinfo->data_unit;
+ register JSAMPROW inptr, outptr;
+ register int bias;
+
+ /* Expand input data enough to let all the output samples be generated
+ * by the standard loop. Special-casing padded output would be more
+ * efficient.
+ */
+ expand_right_edge(input_data, cinfo->max_v_samp_factor,
+ cinfo->image_width, output_cols * 2);
+
+ for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
+ outptr = output_data[outrow];
+ inptr = input_data[outrow];
+ bias = 0; /* bias = 0,1,0,1,... for successive samples */
+ for (outcol = 0; outcol < output_cols; outcol++) {
+ *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr) + GETJSAMPLE(inptr[1])
+ + bias) >> 1);
+ bias ^= 1; /* 0=>1, 1=>0 */
+ inptr += 2;
+ }
+ }
+}
+
+
+/*
+ * Downsample pixel values of a single component.
+ * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
+ * without smoothing.
+ */
+
+METHODDEF(void)
+h2v2_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data)
+{
+ int inrow, outrow;
+ JDIMENSION outcol;
+ JDIMENSION output_cols = compptr->width_in_data_units * cinfo->data_unit;
+ register JSAMPROW inptr0, inptr1, outptr;
+ register int bias;
+
+ /* Expand input data enough to let all the output samples be generated
+ * by the standard loop. Special-casing padded output would be more
+ * efficient.
+ */
+ expand_right_edge(input_data, cinfo->max_v_samp_factor,
+ cinfo->image_width, output_cols * 2);
+
+ inrow = 0;
+ for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
+ outptr = output_data[outrow];
+ inptr0 = input_data[inrow];
+ inptr1 = input_data[inrow+1];
+ bias = 1; /* bias = 1,2,1,2,... for successive samples */
+ for (outcol = 0; outcol < output_cols; outcol++) {
+ *outptr++ = (JSAMPLE) ((GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
+ GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1])
+ + bias) >> 2);
+ bias ^= 3; /* 1=>2, 2=>1 */
+ inptr0 += 2; inptr1 += 2;
+ }
+ inrow += 2;
+ }
+}
+
+
+#ifdef INPUT_SMOOTHING_SUPPORTED
+
+/*
+ * Downsample pixel values of a single component.
+ * This version handles the standard case of 2:1 horizontal and 2:1 vertical,
+ * with smoothing. One row of context is required.
+ */
+
+METHODDEF(void)
+h2v2_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data)
+{
+ int inrow, outrow;
+ JDIMENSION colctr;
+ JDIMENSION output_cols = compptr->width_in_data_units * cinfo->data_unit;
+ register JSAMPROW inptr0, inptr1, above_ptr, below_ptr, outptr;
+ INT32 membersum, neighsum, memberscale, neighscale;
+
+ /* Expand input data enough to let all the output samples be generated
+ * by the standard loop. Special-casing padded output would be more
+ * efficient.
+ */
+ expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
+ cinfo->image_width, output_cols * 2);
+
+ /* We don't bother to form the individual "smoothed" input pixel values;
+ * we can directly compute the output which is the average of the four
+ * smoothed values. Each of the four member pixels contributes a fraction
+ * (1-8*SF) to its own smoothed image and a fraction SF to each of the three
+ * other smoothed pixels, therefore a total fraction (1-5*SF)/4 to the final
+ * output. The four corner-adjacent neighbor pixels contribute a fraction
+ * SF to just one smoothed pixel, or SF/4 to the final output; while the
+ * eight edge-adjacent neighbors contribute SF to each of two smoothed
+ * pixels, or SF/2 overall. In order to use integer arithmetic, these
+ * factors are scaled by 2^16 = 65536.
+ * Also recall that SF = smoothing_factor / 1024.
+ */
+
+ memberscale = 16384 - cinfo->smoothing_factor * 80; /* scaled (1-5*SF)/4 */
+ neighscale = cinfo->smoothing_factor * 16; /* scaled SF/4 */
+
+ inrow = 0;
+ for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
+ outptr = output_data[outrow];
+ inptr0 = input_data[inrow];
+ inptr1 = input_data[inrow+1];
+ above_ptr = input_data[inrow-1];
+ below_ptr = input_data[inrow+2];
+
+ /* Special case for first column: pretend column -1 is same as column 0 */
+ membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
+ GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
+ neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
+ GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
+ GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[2]) +
+ GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[2]);
+ neighsum += neighsum;
+ neighsum += GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[2]) +
+ GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[2]);
+ membersum = membersum * memberscale + neighsum * neighscale;
+ *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
+ inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
+
+ for (colctr = output_cols - 2; colctr > 0; colctr--) {
+ /* sum of pixels directly mapped to this output element */
+ membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
+ GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
+ /* sum of edge-neighbor pixels */
+ neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
+ GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
+ GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[2]) +
+ GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[2]);
+ /* The edge-neighbors count twice as much as corner-neighbors */
+ neighsum += neighsum;
+ /* Add in the corner-neighbors */
+ neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[2]) +
+ GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[2]);
+ /* form final output scaled up by 2^16 */
+ membersum = membersum * memberscale + neighsum * neighscale;
+ /* round, descale and output it */
+ *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
+ inptr0 += 2; inptr1 += 2; above_ptr += 2; below_ptr += 2;
+ }
+
+ /* Special case for last column */
+ membersum = GETJSAMPLE(*inptr0) + GETJSAMPLE(inptr0[1]) +
+ GETJSAMPLE(*inptr1) + GETJSAMPLE(inptr1[1]);
+ neighsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(above_ptr[1]) +
+ GETJSAMPLE(*below_ptr) + GETJSAMPLE(below_ptr[1]) +
+ GETJSAMPLE(inptr0[-1]) + GETJSAMPLE(inptr0[1]) +
+ GETJSAMPLE(inptr1[-1]) + GETJSAMPLE(inptr1[1]);
+ neighsum += neighsum;
+ neighsum += GETJSAMPLE(above_ptr[-1]) + GETJSAMPLE(above_ptr[1]) +
+ GETJSAMPLE(below_ptr[-1]) + GETJSAMPLE(below_ptr[1]);
+ membersum = membersum * memberscale + neighsum * neighscale;
+ *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
+
+ inrow += 2;
+ }
+}
+
+
+/*
+ * Downsample pixel values of a single component.
+ * This version handles the special case of a full-size component,
+ * with smoothing. One row of context is required.
+ */
+
+METHODDEF(void)
+fullsize_smooth_downsample (j_compress_ptr cinfo, jpeg_component_info *compptr,
+ JSAMPARRAY input_data, JSAMPARRAY output_data)
+{
+ int outrow;
+ JDIMENSION colctr;
+ JDIMENSION output_cols = compptr->width_in_data_units * cinfo->data_unit;
+ register JSAMPROW inptr, above_ptr, below_ptr, outptr;
+ INT32 membersum, neighsum, memberscale, neighscale;
+ int colsum, lastcolsum, nextcolsum;
+
+ /* Expand input data enough to let all the output samples be generated
+ * by the standard loop. Special-casing padded output would be more
+ * efficient.
+ */
+ expand_right_edge(input_data - 1, cinfo->max_v_samp_factor + 2,
+ cinfo->image_width, output_cols);
+
+ /* Each of the eight neighbor pixels contributes a fraction SF to the
+ * smoothed pixel, while the main pixel contributes (1-8*SF). In order
+ * to use integer arithmetic, these factors are multiplied by 2^16 = 65536.
+ * Also recall that SF = smoothing_factor / 1024.
+ */
+
+ memberscale = 65536L - cinfo->smoothing_factor * 512L; /* scaled 1-8*SF */
+ neighscale = cinfo->smoothing_factor * 64; /* scaled SF */
+
+ for (outrow = 0; outrow < compptr->v_samp_factor; outrow++) {
+ outptr = output_data[outrow];
+ inptr = input_data[outrow];
+ above_ptr = input_data[outrow-1];
+ below_ptr = input_data[outrow+1];
+
+ /* Special case for first column */
+ colsum = GETJSAMPLE(*above_ptr++) + GETJSAMPLE(*below_ptr++) +
+ GETJSAMPLE(*inptr);
+ membersum = GETJSAMPLE(*inptr++);
+ nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
+ GETJSAMPLE(*inptr);
+ neighsum = colsum + (colsum - membersum) + nextcolsum;
+ membersum = membersum * memberscale + neighsum * neighscale;
+ *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
+ lastcolsum = colsum; colsum = nextcolsum;
+
+ for (colctr = output_cols - 2; colctr > 0; colctr--) {
+ membersum = GETJSAMPLE(*inptr++);
+ above_ptr++; below_ptr++;
+ nextcolsum = GETJSAMPLE(*above_ptr) + GETJSAMPLE(*below_ptr) +
+ GETJSAMPLE(*inptr);
+ neighsum = lastcolsum + (colsum - membersum) + nextcolsum;
+ membersum = membersum * memberscale + neighsum * neighscale;
+ *outptr++ = (JSAMPLE) ((membersum + 32768) >> 16);
+ lastcolsum = colsum; colsum = nextcolsum;
+ }
+
+ /* Special case for last column */
+ membersum = GETJSAMPLE(*inptr);
+ neighsum = lastcolsum + (colsum - membersum) + colsum;
+ membersum = membersum * memberscale + neighsum * neighscale;
+ *outptr = (JSAMPLE) ((membersum + 32768) >> 16);
+
+ }
+}
+
+#endif /* INPUT_SMOOTHING_SUPPORTED */
+
+
+/*
+ * Module initialization routine for downsampling.
+ * Note that we must select a routine for each component.
+ */
+
+GLOBAL(void)
+jinit_downsampler (j_compress_ptr cinfo)
+{
+ my_downsample_ptr downsample;
+ int ci;
+ jpeg_component_info * compptr;
+ boolean smoothok = TRUE;
+
+ downsample = (my_downsample_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_downsampler));
+ cinfo->downsample = (struct jpeg_downsampler *) downsample;
+ downsample->pub.start_pass = start_pass_downsample;
+ downsample->pub.downsample = sep_downsample;
+ downsample->pub.need_context_rows = FALSE;
+
+ if (cinfo->CCIR601_sampling)
+ ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
+
+ /* Verify we can handle the sampling factors, and set up method pointers */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (compptr->h_samp_factor == cinfo->max_h_samp_factor &&
+ compptr->v_samp_factor == cinfo->max_v_samp_factor) {
+#ifdef INPUT_SMOOTHING_SUPPORTED
+ if (cinfo->smoothing_factor) {
+ downsample->methods[ci] = fullsize_smooth_downsample;
+ downsample->pub.need_context_rows = TRUE;
+ } else
+#endif
+ downsample->methods[ci] = fullsize_downsample;
+ } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
+ compptr->v_samp_factor == cinfo->max_v_samp_factor) {
+ smoothok = FALSE;
+ downsample->methods[ci] = h2v1_downsample;
+ } else if (compptr->h_samp_factor * 2 == cinfo->max_h_samp_factor &&
+ compptr->v_samp_factor * 2 == cinfo->max_v_samp_factor) {
+#ifdef INPUT_SMOOTHING_SUPPORTED
+ if (cinfo->smoothing_factor) {
+ downsample->methods[ci] = h2v2_smooth_downsample;
+ downsample->pub.need_context_rows = TRUE;
+ } else
+#endif
+ downsample->methods[ci] = h2v2_downsample;
+ } else if ((cinfo->max_h_samp_factor % compptr->h_samp_factor) == 0 &&
+ (cinfo->max_v_samp_factor % compptr->v_samp_factor) == 0) {
+ smoothok = FALSE;
+ downsample->methods[ci] = int_downsample;
+ } else
+ ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
+ }
+
+#ifdef INPUT_SMOOTHING_SUPPORTED
+ if (cinfo->smoothing_factor && !smoothok)
+ TRACEMS(cinfo, 0, JTRC_SMOOTH_NOTIMPL);
+#endif
+}
--- /dev/null
+/*
+ * jcscale.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains sample downscaling by 2^Pt for lossless JPEG.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+
+METHODDEF(void)
+simple_downscale(j_compress_ptr cinfo,
+ JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)
+{
+ /* j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec; */
+ unsigned int xindex;
+ SHIFT_TEMPS
+
+ for (xindex = 0; xindex < width; xindex++)
+ output_buf[xindex] = (JSAMPLE) RIGHT_SHIFT(GETJSAMPLE(input_buf[xindex]),
+ cinfo->Al);
+}
+
+
+METHODDEF(void)
+noscale(j_compress_ptr cinfo,
+ JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)
+{
+ (void)cinfo;
+ MEMCOPY(output_buf, input_buf, width * SIZEOF(JSAMPLE));
+ return;
+}
+
+
+METHODDEF(void)
+scaler_start_pass (j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+
+ /* Set scaler function based on Pt */
+ if (cinfo->Al)
+ losslsc->scaler_scale = simple_downscale;
+ else
+ losslsc->scaler_scale = noscale;
+}
+
+
+GLOBAL(void)
+jinit_c_scaler (j_compress_ptr cinfo)
+{
+ j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+
+ losslsc->scaler_start_pass = scaler_start_pass;
+}
+
+#endif /* C_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jcshuff.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy encoding routines for sequential JPEG.
+ *
+ * Much of the complexity here has to do with supporting output suspension.
+ * If the data destination module demands suspension, we want to be able to
+ * back up to the start of the current MCU. To do this, we copy state
+ * variables into local working storage, and update them back to the
+ * permanent JPEG objects only upon successful completion of an MCU.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+#include "jchuff.h" /* Declarations shared with jc*huff.c */
+
+
+/* Expanded entropy encoder object for Huffman encoding.
+ *
+ * The savable_state subrecord contains fields that change within an MCU,
+ * but must not be updated permanently until we complete the MCU.
+ */
+
+typedef struct {
+ INT32 put_buffer; /* current bit-accumulation buffer */
+ int put_bits; /* # of bits now in it */
+ int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
+} savable_state;
+
+/* This macro is to work around compilers with missing or broken
+ * structure assignment. You'll need to fix this code if you have
+ * such a compiler and you change MAX_COMPS_IN_SCAN.
+ */
+
+#ifndef NO_STRUCT_ASSIGN
+#define ASSIGN_STATE(dest,src) ((dest) = (src))
+#else
+#if MAX_COMPS_IN_SCAN == 4
+#define ASSIGN_STATE(dest,src) \
+ ((dest).put_buffer = (src).put_buffer, \
+ (dest).put_bits = (src).put_bits, \
+ (dest).last_dc_val[0] = (src).last_dc_val[0], \
+ (dest).last_dc_val[1] = (src).last_dc_val[1], \
+ (dest).last_dc_val[2] = (src).last_dc_val[2], \
+ (dest).last_dc_val[3] = (src).last_dc_val[3])
+#endif
+#endif
+
+
+typedef struct {
+ savable_state saved; /* Bit buffer & DC state at start of MCU */
+
+ /* These fields are NOT loaded into local working state. */
+ unsigned int restarts_to_go; /* MCUs left in this restart interval */
+ int next_restart_num; /* next restart number to write (0-7) */
+
+ /* Pointers to derived tables (these workspaces have image lifespan) */
+ c_derived_tbl * dc_derived_tbls[NUM_HUFF_TBLS];
+ c_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS];
+
+#ifdef ENTROPY_OPT_SUPPORTED /* Statistics tables for optimization */
+ long * dc_count_ptrs[NUM_HUFF_TBLS];
+ long * ac_count_ptrs[NUM_HUFF_TBLS];
+#endif
+} shuff_entropy_encoder;
+
+typedef shuff_entropy_encoder * shuff_entropy_ptr;
+
+/* Working state while writing an MCU.
+ * This struct contains all the fields that are needed by subroutines.
+ */
+
+typedef struct {
+ JOCTET * next_output_byte; /* => next byte to write in buffer */
+ size_t free_in_buffer; /* # of byte spaces remaining in buffer */
+ savable_state cur; /* Current bit buffer & DC state */
+ j_compress_ptr cinfo; /* dump_buffer needs access to this */
+} working_state;
+
+
+/* Forward declarations */
+METHODDEF(boolean) encode_mcu_huff JPP((j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(void) finish_pass_huff JPP((j_compress_ptr cinfo));
+#ifdef ENTROPY_OPT_SUPPORTED
+METHODDEF(boolean) encode_mcu_gather JPP((j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(void) finish_pass_gather JPP((j_compress_ptr cinfo));
+#endif
+
+
+/*
+ * Initialize for a Huffman-compressed scan.
+ * If gather_statistics is TRUE, we do not output anything during the scan,
+ * just count the Huffman symbols used and generate Huffman code tables.
+ */
+
+METHODDEF(void)
+start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyc->entropy_private;
+ int ci, dctbl, actbl;
+ jpeg_component_info * compptr;
+
+ if (gather_statistics) {
+#ifdef ENTROPY_OPT_SUPPORTED
+ lossyc->entropy_encode_mcu = encode_mcu_gather;
+ lossyc->pub.entropy_finish_pass = finish_pass_gather;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ lossyc->entropy_encode_mcu = encode_mcu_huff;
+ lossyc->pub.entropy_finish_pass = finish_pass_huff;
+ }
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ dctbl = compptr->dc_tbl_no;
+ actbl = compptr->ac_tbl_no;
+ if (gather_statistics) {
+#ifdef ENTROPY_OPT_SUPPORTED
+ /* Check for invalid table indexes */
+ /* (make_c_derived_tbl does this in the other path) */
+ if (dctbl < 0 || dctbl >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, dctbl);
+ if (actbl < 0 || actbl >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, actbl);
+ /* Allocate and zero the statistics tables */
+ /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
+ if (entropy->dc_count_ptrs[dctbl] == NULL)
+ entropy->dc_count_ptrs[dctbl] = (long *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ 257 * SIZEOF(long));
+ MEMZERO(entropy->dc_count_ptrs[dctbl], 257 * SIZEOF(long));
+ if (entropy->ac_count_ptrs[actbl] == NULL)
+ entropy->ac_count_ptrs[actbl] = (long *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ 257 * SIZEOF(long));
+ MEMZERO(entropy->ac_count_ptrs[actbl], 257 * SIZEOF(long));
+#endif
+ } else {
+ /* Compute derived values for Huffman tables */
+ /* We may do this more than once for a table, but it's not expensive */
+ jpeg_make_c_derived_tbl(cinfo, TRUE, dctbl,
+ & entropy->dc_derived_tbls[dctbl]);
+ jpeg_make_c_derived_tbl(cinfo, FALSE, actbl,
+ & entropy->ac_derived_tbls[actbl]);
+ }
+ /* Initialize DC predictions to 0 */
+ entropy->saved.last_dc_val[ci] = 0;
+ }
+
+ /* Initialize bit buffer to empty */
+ entropy->saved.put_buffer = 0;
+ entropy->saved.put_bits = 0;
+
+ /* Initialize restart stuff */
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num = 0;
+}
+
+
+/* Outputting bytes to the file */
+
+/* Emit a byte, taking 'action' if must suspend. */
+#define emit_byte(state,val,action) \
+ { *(state)->next_output_byte++ = (JOCTET) (val); \
+ if (--(state)->free_in_buffer == 0) \
+ if (! dump_buffer(state)) \
+ { action; } }
+
+
+LOCAL(boolean)
+dump_buffer (working_state * state)
+/* Empty the output buffer; return TRUE if successful, FALSE if must suspend */
+{
+ struct jpeg_destination_mgr * dest = state->cinfo->dest;
+
+ if (! (*dest->empty_output_buffer) (state->cinfo))
+ return FALSE;
+ /* After a successful buffer dump, must reset buffer pointers */
+ state->next_output_byte = dest->next_output_byte;
+ state->free_in_buffer = dest->free_in_buffer;
+ return TRUE;
+}
+
+
+/* Outputting bits to the file */
+
+/* Only the right 24 bits of put_buffer are used; the valid bits are
+ * left-justified in this part. At most 16 bits can be passed to emit_bits
+ * in one call, and we never retain more than 7 bits in put_buffer
+ * between calls, so 24 bits are sufficient.
+ */
+
+INLINE
+LOCAL(boolean)
+emit_bits (working_state * state, unsigned int code, int size)
+/* Emit some bits; return TRUE if successful, FALSE if must suspend */
+{
+ /* This routine is heavily used, so it's worth coding tightly. */
+ register INT32 put_buffer = (INT32) code;
+ register int put_bits = state->cur.put_bits;
+
+ /* if size is 0, caller used an invalid Huffman table entry */
+ if (size == 0)
+ ERREXIT(state->cinfo, JERR_HUFF_MISSING_CODE);
+
+ put_buffer &= (((INT32) 1)<<size) - 1; /* mask off any extra bits in code */
+
+ put_bits += size; /* new number of bits in buffer */
+
+ put_buffer <<= 24 - put_bits; /* align incoming bits */
+
+ put_buffer |= state->cur.put_buffer; /* and merge with old buffer contents */
+
+ while (put_bits >= 8) {
+ int c = (int) ((put_buffer >> 16) & 0xFF);
+
+ emit_byte(state, c, return FALSE);
+ if (c == 0xFF) { /* need to stuff a zero byte? */
+ emit_byte(state, 0, return FALSE);
+ }
+ put_buffer <<= 8;
+ put_bits -= 8;
+ }
+
+ state->cur.put_buffer = put_buffer; /* update state variables */
+ state->cur.put_bits = put_bits;
+
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+flush_bits (working_state * state)
+{
+ if (! emit_bits(state, 0x7F, 7)) /* fill any partial byte with ones */
+ return FALSE;
+ state->cur.put_buffer = 0; /* and reset bit-buffer to empty */
+ state->cur.put_bits = 0;
+ return TRUE;
+}
+
+
+/* Encode a single block's worth of coefficients */
+
+LOCAL(boolean)
+encode_one_block (working_state * state, JCOEFPTR block, int last_dc_val,
+ c_derived_tbl *dctbl, c_derived_tbl *actbl)
+{
+ register int temp, temp2;
+ register int nbits;
+ register int k, r, i;
+
+ /* Encode the DC coefficient difference per section F.1.2.1 */
+
+ temp = temp2 = block[0] - last_dc_val;
+
+ if (temp < 0) {
+ temp = -temp; /* temp is abs value of input */
+ /* For a negative input, want temp2 = bitwise complement of abs(input) */
+ /* This code assumes we are on a two's complement machine */
+ temp2--;
+ }
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ nbits = 0;
+ while (temp) {
+ nbits++;
+ temp >>= 1;
+ }
+ /* Check for out-of-range coefficient values.
+ * Since we're encoding a difference, the range limit is twice as much.
+ */
+ if (nbits > MAX_COEF_BITS+1)
+ ERREXIT(state->cinfo, JERR_BAD_DCT_COEF);
+
+ /* Emit the Huffman-coded symbol for the number of bits */
+ if (! emit_bits(state, dctbl->ehufco[nbits], dctbl->ehufsi[nbits]))
+ return FALSE;
+
+ /* Emit that number of bits of the value, if positive, */
+ /* or the complement of its magnitude, if negative. */
+ if (nbits) /* emit_bits rejects calls with size 0 */
+ if (! emit_bits(state, (unsigned int) temp2, nbits))
+ return FALSE;
+
+ /* Encode the AC coefficients per section F.1.2.2 */
+
+ r = 0; /* r = run length of zeros */
+
+ for (k = 1; k < DCTSIZE2; k++) {
+ if ((temp = block[jpeg_natural_order[k]]) == 0) {
+ r++;
+ } else {
+ /* if run length > 15, must emit special run-length-16 codes (0xF0) */
+ while (r > 15) {
+ if (! emit_bits(state, actbl->ehufco[0xF0], actbl->ehufsi[0xF0]))
+ return FALSE;
+ r -= 16;
+ }
+
+ temp2 = temp;
+ if (temp < 0) {
+ temp = -temp; /* temp is abs value of input */
+ /* This code assumes we are on a two's complement machine */
+ temp2--;
+ }
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ nbits = 1; /* there must be at least one 1 bit */
+ while ((temp >>= 1))
+ nbits++;
+ /* Check for out-of-range coefficient values */
+ if (nbits > MAX_COEF_BITS)
+ ERREXIT(state->cinfo, JERR_BAD_DCT_COEF);
+
+ /* Emit Huffman symbol for run length / number of bits */
+ i = (r << 4) + nbits;
+ if (! emit_bits(state, actbl->ehufco[i], actbl->ehufsi[i]))
+ return FALSE;
+
+ /* Emit that number of bits of the value, if positive, */
+ /* or the complement of its magnitude, if negative. */
+ if (! emit_bits(state, (unsigned int) temp2, nbits))
+ return FALSE;
+
+ r = 0;
+ }
+ }
+
+ /* If the last coef(s) were zero, emit an end-of-block code */
+ if (r > 0)
+ if (! emit_bits(state, actbl->ehufco[0], actbl->ehufsi[0]))
+ return FALSE;
+
+ return TRUE;
+}
+
+
+/*
+ * Emit a restart marker & resynchronize predictions.
+ */
+
+LOCAL(boolean)
+emit_restart (working_state * state, int restart_num)
+{
+ int ci;
+
+ if (! flush_bits(state))
+ return FALSE;
+
+ emit_byte(state, 0xFF, return FALSE);
+ emit_byte(state, JPEG_RST0 + restart_num, return FALSE);
+
+ /* Re-initialize DC predictions to 0 */
+ for (ci = 0; ci < state->cinfo->comps_in_scan; ci++)
+ state->cur.last_dc_val[ci] = 0;
+
+ /* The restart counter is not updated until we successfully write the MCU. */
+
+ return TRUE;
+}
+
+
+/*
+ * Encode and output one MCU's worth of Huffman-compressed coefficients.
+ */
+
+METHODDEF(boolean)
+encode_mcu_huff (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyc->entropy_private;
+ working_state state;
+ int blkn, ci;
+ jpeg_component_info * compptr;
+
+ /* Load up working state */
+ state.next_output_byte = cinfo->dest->next_output_byte;
+ state.free_in_buffer = cinfo->dest->free_in_buffer;
+ ASSIGN_STATE(state.cur, entropy->saved);
+ state.cinfo = cinfo;
+
+ /* Emit restart marker if needed */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! emit_restart(&state, entropy->next_restart_num))
+ return FALSE;
+ }
+
+ /* Encode the MCU data blocks */
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ ci = cinfo->MCU_membership[blkn];
+ compptr = cinfo->cur_comp_info[ci];
+ if (! encode_one_block(&state,
+ MCU_data[blkn][0], state.cur.last_dc_val[ci],
+ entropy->dc_derived_tbls[compptr->dc_tbl_no],
+ entropy->ac_derived_tbls[compptr->ac_tbl_no]))
+ return FALSE;
+ /* Update last_dc_val */
+ state.cur.last_dc_val[ci] = MCU_data[blkn][0][0];
+ }
+
+ /* Completed MCU, so update state */
+ cinfo->dest->next_output_byte = state.next_output_byte;
+ cinfo->dest->free_in_buffer = state.free_in_buffer;
+ ASSIGN_STATE(entropy->saved, state.cur);
+
+ /* Update restart-interval state too */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ entropy->restarts_to_go = cinfo->restart_interval;
+ entropy->next_restart_num++;
+ entropy->next_restart_num &= 7;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ return TRUE;
+}
+
+
+/*
+ * Finish up at the end of a Huffman-compressed scan.
+ */
+
+METHODDEF(void)
+finish_pass_huff (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyc->entropy_private;
+ working_state state;
+
+ /* Load up working state ... flush_bits needs it */
+ state.next_output_byte = cinfo->dest->next_output_byte;
+ state.free_in_buffer = cinfo->dest->free_in_buffer;
+ ASSIGN_STATE(state.cur, entropy->saved);
+ state.cinfo = cinfo;
+
+ /* Flush out the last data */
+ if (! flush_bits(&state))
+ ERREXIT(cinfo, JERR_CANT_SUSPEND);
+
+ /* Update state */
+ cinfo->dest->next_output_byte = state.next_output_byte;
+ cinfo->dest->free_in_buffer = state.free_in_buffer;
+ ASSIGN_STATE(entropy->saved, state.cur);
+}
+
+
+/*
+ * Huffman coding optimization.
+ *
+ * We first scan the supplied data and count the number of uses of each symbol
+ * that is to be Huffman-coded. (This process MUST agree with the code above.)
+ * Then we build a Huffman coding tree for the observed counts.
+ * Symbols which are not needed at all for the particular image are not
+ * assigned any code, which saves space in the DHT marker as well as in
+ * the compressed data.
+ */
+
+#ifdef ENTROPY_OPT_SUPPORTED
+
+
+/* Process a single block's worth of coefficients */
+
+LOCAL(void)
+htest_one_block (j_compress_ptr cinfo, JCOEFPTR block, int last_dc_val,
+ long dc_counts[], long ac_counts[])
+{
+ register int temp;
+ register int nbits;
+ register int k, r;
+
+ /* Encode the DC coefficient difference per section F.1.2.1 */
+
+ temp = block[0] - last_dc_val;
+ if (temp < 0)
+ temp = -temp;
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ nbits = 0;
+ while (temp) {
+ nbits++;
+ temp >>= 1;
+ }
+ /* Check for out-of-range coefficient values.
+ * Since we're encoding a difference, the range limit is twice as much.
+ */
+ if (nbits > MAX_COEF_BITS+1)
+ ERREXIT(cinfo, JERR_BAD_DCT_COEF);
+
+ /* Count the Huffman symbol for the number of bits */
+ dc_counts[nbits]++;
+
+ /* Encode the AC coefficients per section F.1.2.2 */
+
+ r = 0; /* r = run length of zeros */
+
+ for (k = 1; k < DCTSIZE2; k++) {
+ if ((temp = block[jpeg_natural_order[k]]) == 0) {
+ r++;
+ } else {
+ /* if run length > 15, must emit special run-length-16 codes (0xF0) */
+ while (r > 15) {
+ ac_counts[0xF0]++;
+ r -= 16;
+ }
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ if (temp < 0)
+ temp = -temp;
+
+ /* Find the number of bits needed for the magnitude of the coefficient */
+ nbits = 1; /* there must be at least one 1 bit */
+ while ((temp >>= 1))
+ nbits++;
+ /* Check for out-of-range coefficient values */
+ if (nbits > MAX_COEF_BITS)
+ ERREXIT(cinfo, JERR_BAD_DCT_COEF);
+
+ /* Count Huffman symbol for run length / number of bits */
+ ac_counts[(r << 4) + nbits]++;
+
+ r = 0;
+ }
+ }
+
+ /* If the last coef(s) were zero, emit an end-of-block code */
+ if (r > 0)
+ ac_counts[0]++;
+}
+
+
+/*
+ * Trial-encode one MCU's worth of Huffman-compressed coefficients.
+ * No data is actually output, so no suspension return is possible.
+ */
+
+METHODDEF(boolean)
+encode_mcu_gather (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyc->entropy_private;
+ int blkn, ci;
+ jpeg_component_info * compptr;
+
+ /* Take care of restart intervals if needed */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0) {
+ /* Re-initialize DC predictions to 0 */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++)
+ entropy->saved.last_dc_val[ci] = 0;
+ /* Update restart state */
+ entropy->restarts_to_go = cinfo->restart_interval;
+ }
+ entropy->restarts_to_go--;
+ }
+
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ ci = cinfo->MCU_membership[blkn];
+ compptr = cinfo->cur_comp_info[ci];
+ htest_one_block(cinfo, MCU_data[blkn][0], entropy->saved.last_dc_val[ci],
+ entropy->dc_count_ptrs[compptr->dc_tbl_no],
+ entropy->ac_count_ptrs[compptr->ac_tbl_no]);
+ entropy->saved.last_dc_val[ci] = MCU_data[blkn][0][0];
+ }
+
+ return TRUE;
+}
+
+
+/*
+ * Finish up a statistics-gathering pass and create the new Huffman tables.
+ */
+
+METHODDEF(void)
+finish_pass_gather (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyc->entropy_private;
+ int ci, dctbl, actbl;
+ jpeg_component_info * compptr;
+ JHUFF_TBL **htblptr;
+ boolean did_dc[NUM_HUFF_TBLS];
+ boolean did_ac[NUM_HUFF_TBLS];
+
+ /* It's important not to apply jpeg_gen_optimal_table more than once
+ * per table, because it clobbers the input frequency counts!
+ */
+ MEMZERO(did_dc, SIZEOF(did_dc));
+ MEMZERO(did_ac, SIZEOF(did_ac));
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ dctbl = compptr->dc_tbl_no;
+ actbl = compptr->ac_tbl_no;
+ if (! did_dc[dctbl]) {
+ htblptr = & cinfo->dc_huff_tbl_ptrs[dctbl];
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+ jpeg_gen_optimal_table(cinfo, *htblptr, entropy->dc_count_ptrs[dctbl]);
+ did_dc[dctbl] = TRUE;
+ }
+ if (! did_ac[actbl]) {
+ htblptr = & cinfo->ac_huff_tbl_ptrs[actbl];
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+ jpeg_gen_optimal_table(cinfo, *htblptr, entropy->ac_count_ptrs[actbl]);
+ did_ac[actbl] = TRUE;
+ }
+ }
+}
+
+
+#endif /* ENTROPY_OPT_SUPPORTED */
+
+
+METHODDEF(boolean)
+need_optimization_pass (j_compress_ptr cinfo)
+{
+ (void)cinfo;
+ return TRUE;
+}
+
+
+/*
+ * Module initialization routine for Huffman entropy encoding.
+ */
+
+GLOBAL(void)
+jinit_shuff_encoder (j_compress_ptr cinfo)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy;
+ int i;
+
+ entropy = (shuff_entropy_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(shuff_entropy_encoder));
+ lossyc->entropy_private = (struct jpeg_entropy_encoder *) entropy;
+ lossyc->pub.entropy_start_pass = start_pass_huff;
+ lossyc->pub.need_optimization_pass = need_optimization_pass;
+
+ /* Mark tables unallocated */
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL;
+#ifdef ENTROPY_OPT_SUPPORTED
+ entropy->dc_count_ptrs[i] = entropy->ac_count_ptrs[i] = NULL;
+#endif
+ }
+}
--- /dev/null
+/*
+ * jctrans.c
+ *
+ * Copyright (C) 1995-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains library routines for transcoding compression,
+ * that is, writing raw DCT coefficient arrays to an output JPEG file.
+ * The routines in jcapimin.c will also be needed by a transcoder.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+
+
+/* Forward declarations */
+LOCAL(void) transencode_master_selection
+ JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
+LOCAL(void) transencode_codec
+ JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
+LOCAL(void) transencode_coef_controller
+ JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));
+
+
+/*
+ * Compression initialization for writing raw-coefficient data.
+ * Before calling this, all parameters and a data destination must be set up.
+ * Call jpeg_finish_compress() to actually write the data.
+ *
+ * The number of passed virtual arrays must match cinfo->num_components.
+ * Note that the virtual arrays need not be filled or even realized at
+ * the time write_coefficients is called; indeed, if the virtual arrays
+ * were requested from this compression object's memory manager, they
+ * typically will be realized during this routine and filled afterwards.
+ */
+
+GLOBAL(void)
+jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)
+{
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ /* Mark all tables to be written */
+ jpeg_suppress_tables(cinfo, FALSE);
+ /* (Re)initialize error mgr and destination modules */
+ (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
+ (*cinfo->dest->init_destination) (cinfo);
+ /* Perform master selection of active modules */
+ transencode_master_selection(cinfo, coef_arrays);
+ /* Wait for jpeg_finish_compress() call */
+ cinfo->next_scanline = 0; /* so jpeg_write_marker works */
+ cinfo->global_state = CSTATE_WRCOEFS;
+}
+
+
+/*
+ * Initialize the compression object with default parameters,
+ * then copy from the source object all parameters needed for lossless
+ * transcoding. Parameters that can be varied without loss (such as
+ * scan script and Huffman optimization) are left in their default states.
+ */
+
+GLOBAL(void)
+jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,
+ j_compress_ptr dstinfo)
+{
+ JQUANT_TBL ** qtblptr;
+ jpeg_component_info *incomp, *outcomp;
+ JQUANT_TBL *c_quant, *slot_quant;
+ int tblno, ci, coefi;
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (dstinfo->global_state != CSTATE_START)
+ ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
+ /* Copy fundamental image dimensions */
+ dstinfo->image_width = srcinfo->image_width;
+ dstinfo->image_height = srcinfo->image_height;
+ dstinfo->input_components = srcinfo->num_components;
+ dstinfo->in_color_space = srcinfo->jpeg_color_space;
+ /* Initialize all parameters to default values */
+ jpeg_set_defaults(dstinfo);
+ /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
+ * Fix it to get the right header markers for the image colorspace.
+ */
+ jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
+ dstinfo->data_precision = srcinfo->data_precision;
+ dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
+ /* Copy the source's quantization tables. */
+ for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
+ if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {
+ qtblptr = & dstinfo->quant_tbl_ptrs[tblno];
+ if (*qtblptr == NULL)
+ *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);
+ MEMCOPY((*qtblptr)->quantval,
+ srcinfo->quant_tbl_ptrs[tblno]->quantval,
+ SIZEOF((*qtblptr)->quantval));
+ (*qtblptr)->sent_table = FALSE;
+ }
+ }
+ /* Copy the source's per-component info.
+ * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
+ */
+ dstinfo->num_components = srcinfo->num_components;
+ if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
+ ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
+ MAX_COMPONENTS);
+ for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
+ ci < dstinfo->num_components; ci++, incomp++, outcomp++) {
+ outcomp->component_id = incomp->component_id;
+ outcomp->h_samp_factor = incomp->h_samp_factor;
+ outcomp->v_samp_factor = incomp->v_samp_factor;
+ outcomp->quant_tbl_no = incomp->quant_tbl_no;
+ /* Make sure saved quantization table for component matches the qtable
+ * slot. If not, the input file re-used this qtable slot.
+ * IJG encoder currently cannot duplicate this.
+ */
+ tblno = outcomp->quant_tbl_no;
+ if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
+ srcinfo->quant_tbl_ptrs[tblno] == NULL)
+ ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
+ slot_quant = srcinfo->quant_tbl_ptrs[tblno];
+ c_quant = incomp->quant_table;
+ if (c_quant != NULL) {
+ for (coefi = 0; coefi < DCTSIZE2; coefi++) {
+ if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
+ ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
+ }
+ }
+ /* Note: we do not copy the source's Huffman table assignments;
+ * instead we rely on jpeg_set_colorspace to have made a suitable choice.
+ */
+ }
+ /* Also copy JFIF version and resolution information, if available.
+ * Strictly speaking this isn't "critical" info, but it's nearly
+ * always appropriate to copy it if available. In particular,
+ * if the application chooses to copy JFIF 1.02 extension markers from
+ * the source file, we need to copy the version to make sure we don't
+ * emit a file that has 1.02 extensions but a claimed version of 1.01.
+ * We will *not*, however, copy version info from mislabeled "2.01" files.
+ */
+ if (srcinfo->saw_JFIF_marker) {
+ if (srcinfo->JFIF_major_version == 1) {
+ dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
+ dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
+ }
+ dstinfo->density_unit = srcinfo->density_unit;
+ dstinfo->X_density = srcinfo->X_density;
+ dstinfo->Y_density = srcinfo->Y_density;
+ }
+}
+
+
+/*
+ * Master selection of compression modules for transcoding.
+ * This substitutes for jcinit.c's initialization of the full compressor.
+ */
+
+LOCAL(void)
+transencode_master_selection (j_compress_ptr cinfo,
+ jvirt_barray_ptr * coef_arrays)
+{
+ cinfo->data_unit = DCTSIZE;
+ /* Although we don't actually use input_components for transcoding,
+ * jcmaster.c's initial_setup will complain if input_components is 0.
+ */
+ cinfo->input_components = 1;
+ /* Initialize master control (includes parameter checking/processing) */
+ jinit_c_master_control(cinfo, TRUE /* transcode only */);
+
+ /* We need a special compression codec. */
+ transencode_codec(cinfo, coef_arrays);
+
+ jinit_marker_writer(cinfo);
+
+ /* We can now tell the memory manager to allocate virtual arrays. */
+ (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
+
+ /* Write the datastream header (SOI, JFIF) immediately.
+ * Frame and scan headers are postponed till later.
+ * This lets application insert special markers after the SOI.
+ */
+ (*cinfo->marker->write_file_header) (cinfo);
+}
+
+
+/*
+ * The rest of this file is a special implementation of the coefficient
+ * buffer controller. This is similar to jccoefct.c, but it handles only
+ * output from presupplied virtual arrays. Furthermore, we generate any
+ * dummy padding blocks on-the-fly rather than expecting them to be present
+ * in the arrays.
+ */
+
+/* Private buffer controller object */
+
+typedef struct {
+ JDIMENSION iMCU_row_num; /* iMCU row # within image */
+ JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
+ int MCU_vert_offset; /* counts MCU rows within iMCU row */
+ int MCU_rows_per_iMCU_row; /* number of such rows needed */
+
+ /* Virtual block array for each component. */
+ jvirt_barray_ptr * whole_image;
+
+ /* Workspace for constructing dummy blocks at right/bottom edges. */
+ JBLOCKROW dummy_buffer[C_MAX_DATA_UNITS_IN_MCU];
+} c_coef_controller;
+
+typedef c_coef_controller * c_coef_ptr;
+
+
+LOCAL(void)
+start_iMCU_row (j_compress_ptr cinfo)
+/* Reset within-iMCU-row counters for a new row */
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+
+ /* In an interleaved scan, an MCU row is the same as an iMCU row.
+ * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
+ * But at the bottom of the image, process only what's left.
+ */
+ if (cinfo->comps_in_scan > 1) {
+ coef->MCU_rows_per_iMCU_row = 1;
+ } else {
+ if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
+ coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
+ else
+ coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
+ }
+
+ coef->mcu_ctr = 0;
+ coef->MCU_vert_offset = 0;
+}
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+
+ if (pass_mode != JBUF_CRANK_DEST)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+
+ coef->iMCU_row_num = 0;
+ start_iMCU_row(cinfo);
+}
+
+
+/*
+ * Process some data.
+ * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
+ * per call, ie, v_samp_factor block rows for each component in the scan.
+ * The data is obtained from the virtual arrays and fed to the entropy coder.
+ * Returns TRUE if the iMCU row is completed, FALSE if suspended.
+ *
+ * NB: input_buf is ignored; it is likely to be a NULL pointer.
+ */
+
+METHODDEF(boolean)
+compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ int blkn, ci, xindex, yindex, yoffset, blockcnt;
+ JDIMENSION start_col;
+ JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
+ JBLOCKROW MCU_buffer[C_MAX_DATA_UNITS_IN_MCU];
+ JBLOCKROW buffer_ptr;
+ jpeg_component_info *compptr;
+ (void)input_buf;
+
+ /* Align the virtual buffers for the components used in this scan. */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ buffer[ci] = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
+ coef->iMCU_row_num * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, FALSE);
+ }
+
+ /* Loop to process one whole iMCU row */
+ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
+ yoffset++) {
+ for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
+ MCU_col_num++) {
+ /* Construct list of pointers to DCT blocks belonging to this MCU */
+ blkn = 0; /* index of current DCT block within MCU */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ start_col = MCU_col_num * compptr->MCU_width;
+ blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
+ : compptr->last_col_width;
+ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
+ if (coef->iMCU_row_num < last_iMCU_row ||
+ yindex+yoffset < compptr->last_row_height) {
+ /* Fill in pointers to real blocks in this row */
+ buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
+ for (xindex = 0; xindex < blockcnt; xindex++)
+ MCU_buffer[blkn++] = buffer_ptr++;
+ } else {
+ /* At bottom of image, need a whole row of dummy blocks */
+ xindex = 0;
+ }
+ /* Fill in any dummy blocks needed in this row.
+ * Dummy blocks are filled in the same way as in jccoefct.c:
+ * all zeroes in the AC entries, DC entries equal to previous
+ * block's DC value. The init routine has already zeroed the
+ * AC entries, so we need only set the DC entries correctly.
+ */
+ for (; xindex < compptr->MCU_width; xindex++) {
+ MCU_buffer[blkn] = coef->dummy_buffer[blkn];
+ MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];
+ blkn++;
+ }
+ }
+ }
+ /* Try to write the MCU. */
+ if (! (*lossyc->entropy_encode_mcu) (cinfo, MCU_buffer)) {
+ /* Suspension forced; update state counters and exit */
+ coef->MCU_vert_offset = yoffset;
+ coef->mcu_ctr = MCU_col_num;
+ return FALSE;
+ }
+ }
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ coef->mcu_ctr = 0;
+ }
+ /* Completed the iMCU row, advance counters for next one */
+ coef->iMCU_row_num++;
+ start_iMCU_row(cinfo);
+ return TRUE;
+}
+
+
+/*
+ * Initialize coefficient buffer controller.
+ *
+ * Each passed coefficient array must be the right size for that
+ * coefficient: width_in_data_units wide and height_in_data_units high,
+ * with unitheight at least v_samp_factor.
+ */
+
+LOCAL(void)
+transencode_coef_controller (j_compress_ptr cinfo,
+ jvirt_barray_ptr * coef_arrays)
+{
+ j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
+ c_coef_ptr coef;
+ JBLOCKROW buffer;
+ int i;
+
+ coef = (c_coef_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(c_coef_controller));
+ lossyc->coef_private = (struct jpeg_c_coef_controller *) coef;
+
+ /* Save pointer to virtual arrays */
+ coef->whole_image = coef_arrays;
+
+ /* Allocate and pre-zero space for dummy DCT blocks. */
+ buffer = (JBLOCKROW)
+ (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
+ jzero_far((void FAR *) buffer, C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
+ for (i = 0; i < C_MAX_DATA_UNITS_IN_MCU; i++) {
+ coef->dummy_buffer[i] = buffer + i;
+ }
+}
+
+
+/*
+ * Initialize the transencoer codec.
+ * This is called only once, during master selection.
+ */
+
+LOCAL(void)
+transencode_codec (j_compress_ptr cinfo,
+ jvirt_barray_ptr * coef_arrays)
+{
+ j_lossy_c_ptr lossyc;
+
+ /* Create subobject in permanent pool */
+ lossyc = (j_lossy_c_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(jpeg_lossy_c_codec));
+ cinfo->codec = (struct jpeg_c_codec *) lossyc;
+
+ /* Initialize sub-modules */
+
+ /* Entropy encoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+ jinit_arith_encoder(cinfo);
+ } else {
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+#ifdef C_PROGRESSIVE_SUPPORTED
+ jinit_phuff_encoder(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else
+ jinit_shuff_encoder(cinfo);
+ }
+
+ /* We need a special coefficient buffer controller. */
+ transencode_coef_controller(cinfo, coef_arrays);
+
+ /* Initialize method pointers */
+ lossyc->pub.start_pass = start_pass_coef;
+ lossyc->pub.compress_data = compress_output;
+}
--- /dev/null
+/*
+ * jdapimin.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains application interface code for the decompression half
+ * of the JPEG library. These are the "minimum" API routines that may be
+ * needed in either the normal full-decompression case or the
+ * transcoding-only case.
+ *
+ * Most of the routines intended to be called directly by an application
+ * are in this file or in jdapistd.c. But also see jcomapi.c for routines
+ * shared by compression and decompression, and jdtrans.c for the transcoding
+ * case.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Initialization of a JPEG decompression object.
+ * The error manager must already be set up (in case memory manager fails).
+ */
+
+GLOBAL(void)
+jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
+{
+ int i;
+
+ /* Guard against version mismatches between library and caller. */
+ cinfo->mem = NULL; /* so jpeg_destroy knows mem mgr not called */
+ if (version != JPEG_LIB_VERSION)
+ ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
+ if (structsize != SIZEOF(struct jpeg_decompress_struct))
+ ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
+ (int) SIZEOF(struct jpeg_decompress_struct), (int) structsize);
+
+ /* For debugging purposes, we zero the whole master structure.
+ * But the application has already set the err pointer, and may have set
+ * client_data, so we have to save and restore those fields.
+ * Note: if application hasn't set client_data, tools like Purify may
+ * complain here.
+ */
+ {
+ struct jpeg_error_mgr * err = cinfo->err;
+ void * client_data = cinfo->client_data; /* ignore Purify complaint here */
+ MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct));
+ cinfo->err = err;
+ cinfo->client_data = client_data;
+ }
+ cinfo->is_decompressor = TRUE;
+
+ /* Initialize a memory manager instance for this object */
+ jinit_memory_mgr((j_common_ptr) cinfo);
+
+ /* Zero out pointers to permanent structures. */
+ cinfo->progress = NULL;
+ cinfo->src = NULL;
+
+ for (i = 0; i < NUM_QUANT_TBLS; i++)
+ cinfo->quant_tbl_ptrs[i] = NULL;
+
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ cinfo->dc_huff_tbl_ptrs[i] = NULL;
+ cinfo->ac_huff_tbl_ptrs[i] = NULL;
+ }
+
+ /* Initialize marker processor so application can override methods
+ * for COM, APPn markers before calling jpeg_read_header.
+ */
+ cinfo->marker_list = NULL;
+ jinit_marker_reader(cinfo);
+
+ /* And initialize the overall input controller. */
+ jinit_input_controller(cinfo);
+
+ /* OK, I'm ready */
+ cinfo->global_state = DSTATE_START;
+}
+
+
+/*
+ * Destruction of a JPEG decompression object
+ */
+
+GLOBAL(void)
+jpeg_destroy_decompress (j_decompress_ptr cinfo)
+{
+ jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
+}
+
+
+/*
+ * Abort processing of a JPEG decompression operation,
+ * but don't destroy the object itself.
+ */
+
+GLOBAL(void)
+jpeg_abort_decompress (j_decompress_ptr cinfo)
+{
+ jpeg_abort((j_common_ptr) cinfo); /* use common routine */
+}
+
+
+/*
+ * Set default decompression parameters.
+ */
+
+LOCAL(void)
+default_decompress_parms (j_decompress_ptr cinfo)
+{
+ /* Guess the input colorspace, and set output colorspace accordingly. */
+ /* (Wish JPEG committee had provided a real way to specify this...) */
+ /* Note application may override our guesses. */
+ switch (cinfo->num_components) {
+ case 1:
+ cinfo->jpeg_color_space = JCS_GRAYSCALE;
+ cinfo->out_color_space = JCS_GRAYSCALE;
+ break;
+
+ case 3:
+ if (cinfo->saw_JFIF_marker) {
+ cinfo->jpeg_color_space = JCS_YCbCr; /* JFIF implies YCbCr */
+ } else if (cinfo->saw_Adobe_marker) {
+ switch (cinfo->Adobe_transform) {
+ case 0:
+ cinfo->jpeg_color_space = JCS_RGB;
+ break;
+ case 1:
+ cinfo->jpeg_color_space = JCS_YCbCr;
+ break;
+ default:
+ WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
+ cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
+ break;
+ }
+ } else {
+ /* Saw no special markers, try to guess from the component IDs */
+ int cid0 = cinfo->comp_info[0].component_id;
+ int cid1 = cinfo->comp_info[1].component_id;
+ int cid2 = cinfo->comp_info[2].component_id;
+
+ if (cid0 == 1 && cid1 == 2 && cid2 == 3)
+ cinfo->jpeg_color_space = JCS_YCbCr; /* assume JFIF w/out marker */
+ else if (cid0 == 82 && cid1 == 71 && cid2 == 66)
+ cinfo->jpeg_color_space = JCS_RGB; /* ASCII 'R', 'G', 'B' */
+ else {
+ if (cinfo->process == JPROC_LOSSLESS) {
+ TRACEMS3(cinfo, 1, JTRC_UNKNOWN_LOSSLESS_IDS, cid0, cid1, cid2);
+ cinfo->jpeg_color_space = JCS_RGB; /* assume it's RGB */
+ }
+ else { /* Lossy processes */
+ TRACEMS3(cinfo, 1, JTRC_UNKNOWN_LOSSY_IDS, cid0, cid1, cid2);
+ cinfo->jpeg_color_space = JCS_YCbCr; /* assume it's YCbCr */
+ }
+ }
+ }
+ /* Always guess RGB is proper output colorspace. */
+ cinfo->out_color_space = JCS_RGB;
+ break;
+
+ case 4:
+ if (cinfo->saw_Adobe_marker) {
+ switch (cinfo->Adobe_transform) {
+ case 0:
+ cinfo->jpeg_color_space = JCS_CMYK;
+ break;
+ case 2:
+ cinfo->jpeg_color_space = JCS_YCCK;
+ break;
+ default:
+ WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
+ cinfo->jpeg_color_space = JCS_YCCK; /* assume it's YCCK */
+ break;
+ }
+ } else {
+ /* No special markers, assume straight CMYK. */
+ cinfo->jpeg_color_space = JCS_CMYK;
+ }
+ cinfo->out_color_space = JCS_CMYK;
+ break;
+
+ default:
+ cinfo->jpeg_color_space = JCS_UNKNOWN;
+ cinfo->out_color_space = JCS_UNKNOWN;
+ break;
+ }
+
+ /* Set defaults for other decompression parameters. */
+ cinfo->scale_num = 1; /* 1:1 scaling */
+ cinfo->scale_denom = 1;
+ cinfo->output_gamma = 1.0;
+ cinfo->buffered_image = FALSE;
+ cinfo->raw_data_out = FALSE;
+ cinfo->dct_method = JDCT_DEFAULT;
+ cinfo->do_fancy_upsampling = TRUE;
+ cinfo->do_block_smoothing = TRUE;
+ cinfo->quantize_colors = FALSE;
+ /* We set these in case application only sets quantize_colors. */
+ cinfo->dither_mode = JDITHER_FS;
+#ifdef QUANT_2PASS_SUPPORTED
+ cinfo->two_pass_quantize = TRUE;
+#else
+ cinfo->two_pass_quantize = FALSE;
+#endif
+ cinfo->desired_number_of_colors = 256;
+ cinfo->colormap = NULL;
+ /* Initialize for no mode change in buffered-image mode. */
+ cinfo->enable_1pass_quant = FALSE;
+ cinfo->enable_external_quant = FALSE;
+ cinfo->enable_2pass_quant = FALSE;
+}
+
+
+/*
+ * Decompression startup: read start of JPEG datastream to see what's there.
+ * Need only initialize JPEG object and supply a data source before calling.
+ *
+ * This routine will read as far as the first SOS marker (ie, actual start of
+ * compressed data), and will save all tables and parameters in the JPEG
+ * object. It will also initialize the decompression parameters to default
+ * values, and finally return JPEG_HEADER_OK. On return, the application may
+ * adjust the decompression parameters and then call jpeg_start_decompress.
+ * (Or, if the application only wanted to determine the image parameters,
+ * the data need not be decompressed. In that case, call jpeg_abort or
+ * jpeg_destroy to release any temporary space.)
+ * If an abbreviated (tables only) datastream is presented, the routine will
+ * return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then
+ * re-use the JPEG object to read the abbreviated image datastream(s).
+ * It is unnecessary (but OK) to call jpeg_abort in this case.
+ * The JPEG_SUSPENDED return code only occurs if the data source module
+ * requests suspension of the decompressor. In this case the application
+ * should load more source data and then re-call jpeg_read_header to resume
+ * processing.
+ * If a non-suspending data source is used and require_image is TRUE, then the
+ * return code need not be inspected since only JPEG_HEADER_OK is possible.
+ *
+ * This routine is now just a front end to jpeg_consume_input, with some
+ * extra error checking.
+ */
+
+GLOBAL(int)
+jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
+{
+ int retcode;
+
+ if (cinfo->global_state != DSTATE_START &&
+ cinfo->global_state != DSTATE_INHEADER)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ retcode = jpeg_consume_input(cinfo);
+
+ switch (retcode) {
+ case JPEG_REACHED_SOS:
+ retcode = JPEG_HEADER_OK;
+ break;
+ case JPEG_REACHED_EOI:
+ if (require_image) /* Complain if application wanted an image */
+ ERREXIT(cinfo, JERR_NO_IMAGE);
+ /* Reset to start state; it would be safer to require the application to
+ * call jpeg_abort, but we can't change it now for compatibility reasons.
+ * A side effect is to free any temporary memory (there shouldn't be any).
+ */
+ jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
+ retcode = JPEG_HEADER_TABLES_ONLY;
+ break;
+ case JPEG_SUSPENDED:
+ /* no work */
+ break;
+ }
+
+ return retcode;
+}
+
+
+/*
+ * Consume data in advance of what the decompressor requires.
+ * This can be called at any time once the decompressor object has
+ * been created and a data source has been set up.
+ *
+ * This routine is essentially a state machine that handles a couple
+ * of critical state-transition actions, namely initial setup and
+ * transition from header scanning to ready-for-start_decompress.
+ * All the actual input is done via the input controller's consume_input
+ * method.
+ */
+
+GLOBAL(int)
+jpeg_consume_input (j_decompress_ptr cinfo)
+{
+ int retcode = JPEG_SUSPENDED;
+
+ /* NB: every possible DSTATE value should be listed in this switch */
+ switch (cinfo->global_state) {
+ case DSTATE_START:
+ /* Start-of-datastream actions: reset appropriate modules */
+ (*cinfo->inputctl->reset_input_controller) (cinfo);
+ /* Initialize application's data source module */
+ (*cinfo->src->init_source) (cinfo);
+ cinfo->global_state = DSTATE_INHEADER;
+ /*FALLTHROUGH*/
+ case DSTATE_INHEADER:
+ retcode = (*cinfo->inputctl->consume_input) (cinfo);
+ if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
+ /* Set up default parameters based on header data */
+ default_decompress_parms(cinfo);
+ /* Set global state: ready for start_decompress */
+ cinfo->global_state = DSTATE_READY;
+ }
+ break;
+ case DSTATE_READY:
+ /* Can't advance past first SOS until start_decompress is called */
+ retcode = JPEG_REACHED_SOS;
+ break;
+ case DSTATE_PRELOAD:
+ case DSTATE_PRESCAN:
+ case DSTATE_SCANNING:
+ case DSTATE_RAW_OK:
+ case DSTATE_BUFIMAGE:
+ case DSTATE_BUFPOST:
+ case DSTATE_STOPPING:
+ retcode = (*cinfo->inputctl->consume_input) (cinfo);
+ break;
+ default:
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ }
+ return retcode;
+}
+
+
+/*
+ * Have we finished reading the input file?
+ */
+
+GLOBAL(boolean)
+jpeg_input_complete (j_decompress_ptr cinfo)
+{
+ /* Check for valid jpeg object */
+ if (cinfo->global_state < DSTATE_START ||
+ cinfo->global_state > DSTATE_STOPPING)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ return cinfo->inputctl->eoi_reached;
+}
+
+
+/*
+ * Is there more than one scan?
+ */
+
+GLOBAL(boolean)
+jpeg_has_multiple_scans (j_decompress_ptr cinfo)
+{
+ /* Only valid after jpeg_read_header completes */
+ if (cinfo->global_state < DSTATE_READY ||
+ cinfo->global_state > DSTATE_STOPPING)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ return cinfo->inputctl->has_multiple_scans;
+}
+
+
+/*
+ * Finish JPEG decompression.
+ *
+ * This will normally just verify the file trailer and release temp storage.
+ *
+ * Returns FALSE if suspended. The return value need be inspected only if
+ * a suspending data source is used.
+ */
+
+GLOBAL(boolean)
+jpeg_finish_decompress (j_decompress_ptr cinfo)
+{
+ if ((cinfo->global_state == DSTATE_SCANNING ||
+ cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
+ /* Terminate final pass of non-buffered mode */
+ if (cinfo->output_scanline < cinfo->output_height)
+ ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
+ (*cinfo->master->finish_output_pass) (cinfo);
+ cinfo->global_state = DSTATE_STOPPING;
+ } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
+ /* Finishing after a buffered-image operation */
+ cinfo->global_state = DSTATE_STOPPING;
+ } else if (cinfo->global_state != DSTATE_STOPPING) {
+ /* STOPPING = repeat call after a suspension, anything else is error */
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ }
+ /* Read until EOI */
+ while (! cinfo->inputctl->eoi_reached) {
+ if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
+ return FALSE; /* Suspend, come back later */
+ }
+ /* Do final cleanup */
+ (*cinfo->src->term_source) (cinfo);
+ /* We can use jpeg_abort to release memory and reset global_state */
+ jpeg_abort((j_common_ptr) cinfo);
+ return TRUE;
+}
--- /dev/null
+/*
+ * jdapistd.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains application interface code for the decompression half
+ * of the JPEG library. These are the "standard" API routines that are
+ * used in the normal full-decompression case. They are not used by a
+ * transcoding-only application. Note that if an application links in
+ * jpeg_start_decompress, it will end up linking in the entire decompressor.
+ * We thus must separate this file from jdapimin.c to avoid linking the
+ * whole decompression library into a transcoder.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Forward declarations */
+LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));
+
+
+/*
+ * Decompression initialization.
+ * jpeg_read_header must be completed before calling this.
+ *
+ * If a multipass operating mode was selected, this will do all but the
+ * last pass, and thus may take a great deal of time.
+ *
+ * Returns FALSE if suspended. The return value need be inspected only if
+ * a suspending data source is used.
+ */
+
+GLOBAL(boolean)
+jpeg_start_decompress (j_decompress_ptr cinfo)
+{
+ if (cinfo->global_state == DSTATE_READY) {
+ /* First call: initialize master control, select active modules */
+ jinit_master_decompress(cinfo);
+ if (cinfo->buffered_image) {
+ /* No more work here; expecting jpeg_start_output next */
+ cinfo->global_state = DSTATE_BUFIMAGE;
+ return TRUE;
+ }
+ cinfo->global_state = DSTATE_PRELOAD;
+ }
+ if (cinfo->global_state == DSTATE_PRELOAD) {
+ /* If file has multiple scans, absorb them all into the coef buffer */
+ if (cinfo->inputctl->has_multiple_scans) {
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+ for (;;) {
+ int retcode;
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL)
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ /* Absorb some more input */
+ retcode = (*cinfo->inputctl->consume_input) (cinfo);
+ if (retcode == JPEG_SUSPENDED)
+ return FALSE;
+ if (retcode == JPEG_REACHED_EOI)
+ break;
+ /* Advance progress counter if appropriate */
+ if (cinfo->progress != NULL &&
+ (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
+ if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
+ /* jdmaster underestimated number of scans; ratchet up one scan */
+ cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
+ }
+ }
+ }
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif /* D_MULTISCAN_FILES_SUPPORTED */
+ }
+ cinfo->output_scan_number = cinfo->input_scan_number;
+ } else if (cinfo->global_state != DSTATE_PRESCAN)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ /* Perform any dummy output passes, and set up for the final pass */
+ return output_pass_setup(cinfo);
+}
+
+
+/*
+ * Set up for an output pass, and perform any dummy pass(es) needed.
+ * Common subroutine for jpeg_start_decompress and jpeg_start_output.
+ * Entry: global_state = DSTATE_PRESCAN only if previously suspended.
+ * Exit: If done, returns TRUE and sets global_state for proper output mode.
+ * If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
+ */
+
+LOCAL(boolean)
+output_pass_setup (j_decompress_ptr cinfo)
+{
+ if (cinfo->global_state != DSTATE_PRESCAN) {
+ /* First call: do pass setup */
+ (*cinfo->master->prepare_for_output_pass) (cinfo);
+ cinfo->output_scanline = 0;
+ cinfo->global_state = DSTATE_PRESCAN;
+ }
+ /* Loop over any required dummy passes */
+ while (cinfo->master->is_dummy_pass) {
+#ifdef QUANT_2PASS_SUPPORTED
+ /* Crank through the dummy pass */
+ while (cinfo->output_scanline < cinfo->output_height) {
+ JDIMENSION last_scanline;
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->output_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->output_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+ /* Process some data */
+ last_scanline = cinfo->output_scanline;
+ (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,
+ &cinfo->output_scanline, (JDIMENSION) 0);
+ if (cinfo->output_scanline == last_scanline)
+ return FALSE; /* No progress made, must suspend */
+ }
+ /* Finish up dummy pass, and set up for another one */
+ (*cinfo->master->finish_output_pass) (cinfo);
+ (*cinfo->master->prepare_for_output_pass) (cinfo);
+ cinfo->output_scanline = 0;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif /* QUANT_2PASS_SUPPORTED */
+ }
+ /* Ready for application to drive output pass through
+ * jpeg_read_scanlines or jpeg_read_raw_data.
+ */
+ cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
+ return TRUE;
+}
+
+
+/*
+ * Read some scanlines of data from the JPEG decompressor.
+ *
+ * The return value will be the number of lines actually read.
+ * This may be less than the number requested in several cases,
+ * including bottom of image, data source suspension, and operating
+ * modes that emit multiple scanlines at a time.
+ *
+ * Note: we warn about excess calls to jpeg_read_scanlines() since
+ * this likely signals an application programmer error. However,
+ * an oversize buffer (max_lines > scanlines remaining) is not an error.
+ */
+
+GLOBAL(JDIMENSION)
+jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,
+ JDIMENSION max_lines)
+{
+ JDIMENSION row_ctr;
+
+ if (cinfo->global_state != DSTATE_SCANNING)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ if (cinfo->output_scanline >= cinfo->output_height) {
+ WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
+ return 0;
+ }
+
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->output_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->output_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+
+ /* Process some data */
+ row_ctr = 0;
+ (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);
+ cinfo->output_scanline += row_ctr;
+ return row_ctr;
+}
+
+
+/*
+ * Alternate entry point to read raw data.
+ * Processes exactly one iMCU row per call, unless suspended.
+ */
+
+GLOBAL(JDIMENSION)
+jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,
+ JDIMENSION max_lines)
+{
+ JDIMENSION lines_per_iMCU_row;
+
+ if (cinfo->global_state != DSTATE_RAW_OK)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ if (cinfo->output_scanline >= cinfo->output_height) {
+ WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
+ return 0;
+ }
+
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->pass_counter = (long) cinfo->output_scanline;
+ cinfo->progress->pass_limit = (long) cinfo->output_height;
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ }
+
+ /* Verify that at least one iMCU row can be returned. */
+ lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_codec_data_unit;
+ if (max_lines < lines_per_iMCU_row)
+ ERREXIT(cinfo, JERR_BUFFER_SIZE);
+
+ /* Decompress directly into user's buffer. */
+ if (! (*cinfo->codec->decompress_data) (cinfo, data))
+ return 0; /* suspension forced, can do nothing more */
+
+ /* OK, we processed one iMCU row. */
+ cinfo->output_scanline += lines_per_iMCU_row;
+ return lines_per_iMCU_row;
+}
+
+
+/* Additional entry points for buffered-image mode. */
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+
+/*
+ * Initialize for an output pass in buffered-image mode.
+ */
+
+GLOBAL(boolean)
+jpeg_start_output (j_decompress_ptr cinfo, int scan_number)
+{
+ if (cinfo->global_state != DSTATE_BUFIMAGE &&
+ cinfo->global_state != DSTATE_PRESCAN)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ /* Limit scan number to valid range */
+ if (scan_number <= 0)
+ scan_number = 1;
+ if (cinfo->inputctl->eoi_reached &&
+ scan_number > cinfo->input_scan_number)
+ scan_number = cinfo->input_scan_number;
+ cinfo->output_scan_number = scan_number;
+ /* Perform any dummy output passes, and set up for the real pass */
+ return output_pass_setup(cinfo);
+}
+
+
+/*
+ * Finish up after an output pass in buffered-image mode.
+ *
+ * Returns FALSE if suspended. The return value need be inspected only if
+ * a suspending data source is used.
+ */
+
+GLOBAL(boolean)
+jpeg_finish_output (j_decompress_ptr cinfo)
+{
+ if ((cinfo->global_state == DSTATE_SCANNING ||
+ cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {
+ /* Terminate this pass. */
+ /* We do not require the whole pass to have been completed. */
+ (*cinfo->master->finish_output_pass) (cinfo);
+ cinfo->global_state = DSTATE_BUFPOST;
+ } else if (cinfo->global_state != DSTATE_BUFPOST) {
+ /* BUFPOST = repeat call after a suspension, anything else is error */
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ }
+ /* Read markers looking for SOS or EOI */
+ while (cinfo->input_scan_number <= cinfo->output_scan_number &&
+ ! cinfo->inputctl->eoi_reached) {
+ if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
+ return FALSE; /* Suspend, come back later */
+ }
+ cinfo->global_state = DSTATE_BUFIMAGE;
+ return TRUE;
+}
+
+#endif /* D_MULTISCAN_FILES_SUPPORTED */
--- /dev/null
+/*
+ * jdarith.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file holds place for arithmetic entropy decoding routines.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * Module initialization routine for arithmetic entropy decoding.
+ */
+
+GLOBAL(void)
+jinit_arith_decoder (j_decompress_ptr cinfo)
+{
+ ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
+}
--- /dev/null
+/*
+ * jdatadst.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains compression data destination routines for the case of
+ * emitting JPEG data to a file (or any stdio stream). While these routines
+ * are sufficient for most applications, some will want to use a different
+ * destination manager.
+ * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
+ * JOCTETs into 8-bit-wide elements on external storage. If char is wider
+ * than 8 bits on your machine, you may need to do some tweaking.
+ */
+
+/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jerror.h"
+
+
+/* Expanded data destination object for stdio output */
+
+typedef struct {
+ struct jpeg_destination_mgr pub; /* public fields */
+
+ FILE * outfile; /* target stream */
+ JOCTET * buffer; /* start of buffer */
+} my_destination_mgr;
+
+typedef my_destination_mgr * my_dest_ptr;
+
+#define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite'able size */
+
+
+/*
+ * Initialize destination --- called by jpeg_start_compress
+ * before any data is actually written.
+ */
+
+METHODDEF(void)
+init_destination (j_compress_ptr cinfo)
+{
+ my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
+
+ /* Allocate the output buffer --- it will be released when done with image */
+ dest->buffer = (JOCTET *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ OUTPUT_BUF_SIZE * SIZEOF(JOCTET));
+
+ dest->pub.next_output_byte = dest->buffer;
+ dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
+}
+
+
+/*
+ * Empty the output buffer --- called whenever buffer fills up.
+ *
+ * In typical applications, this should write the entire output buffer
+ * (ignoring the current state of next_output_byte & free_in_buffer),
+ * reset the pointer & count to the start of the buffer, and return TRUE
+ * indicating that the buffer has been dumped.
+ *
+ * In applications that need to be able to suspend compression due to output
+ * overrun, a FALSE return indicates that the buffer cannot be emptied now.
+ * In this situation, the compressor will return to its caller (possibly with
+ * an indication that it has not accepted all the supplied scanlines). The
+ * application should resume compression after it has made more room in the
+ * output buffer. Note that there are substantial restrictions on the use of
+ * suspension --- see the documentation.
+ *
+ * When suspending, the compressor will back up to a convenient restart point
+ * (typically the start of the current MCU). next_output_byte & free_in_buffer
+ * indicate where the restart point will be if the current call returns FALSE.
+ * Data beyond this point will be regenerated after resumption, so do not
+ * write it out when emptying the buffer externally.
+ */
+
+METHODDEF(boolean)
+empty_output_buffer (j_compress_ptr cinfo)
+{
+ my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
+
+ if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
+ (size_t) OUTPUT_BUF_SIZE)
+ ERREXIT(cinfo, JERR_FILE_WRITE);
+
+ dest->pub.next_output_byte = dest->buffer;
+ dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
+
+ return TRUE;
+}
+
+
+/*
+ * Terminate destination --- called by jpeg_finish_compress
+ * after all data has been written. Usually needs to flush buffer.
+ *
+ * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
+ * application must deal with any cleanup that should happen even
+ * for error exit.
+ */
+
+METHODDEF(void)
+term_destination (j_compress_ptr cinfo)
+{
+ my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
+ size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
+
+ /* Write any data remaining in the buffer */
+ if (datacount > 0) {
+ if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
+ ERREXIT(cinfo, JERR_FILE_WRITE);
+ }
+ fflush(dest->outfile);
+ /* Make sure we wrote the output file OK */
+ if (ferror(dest->outfile))
+ ERREXIT(cinfo, JERR_FILE_WRITE);
+}
+
+
+/*
+ * Prepare for output to a stdio stream.
+ * The caller must have already opened the stream, and is responsible
+ * for closing it after finishing compression.
+ */
+
+GLOBAL(void)
+jpeg_stdio_dest (j_compress_ptr cinfo, FILE * outfile)
+{
+ my_dest_ptr dest;
+
+ /* The destination object is made permanent so that multiple JPEG images
+ * can be written to the same file without re-executing jpeg_stdio_dest.
+ * This makes it dangerous to use this manager and a different destination
+ * manager serially with the same JPEG object, because their private object
+ * sizes may be different. Caveat programmer.
+ */
+ if (cinfo->dest == NULL) { /* first time for this JPEG object? */
+ cinfo->dest = (struct jpeg_destination_mgr *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(my_destination_mgr));
+ }
+
+ dest = (my_dest_ptr) cinfo->dest;
+ dest->pub.init_destination = init_destination;
+ dest->pub.empty_output_buffer = empty_output_buffer;
+ dest->pub.term_destination = term_destination;
+ dest->outfile = outfile;
+}
--- /dev/null
+/*
+ * jdatasrc.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains decompression data source routines for the case of
+ * reading JPEG data from a file (or any stdio stream). While these routines
+ * are sufficient for most applications, some will want to use a different
+ * source manager.
+ * IMPORTANT: we assume that fread() will correctly transcribe an array of
+ * JOCTETs from 8-bit-wide elements on external storage. If char is wider
+ * than 8 bits on your machine, you may need to do some tweaking.
+ */
+
+/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jerror.h"
+
+
+/* Expanded data source object for stdio input */
+
+typedef struct {
+ struct jpeg_source_mgr pub; /* public fields */
+
+ FILE * infile; /* source stream */
+ JOCTET * buffer; /* start of buffer */
+ boolean start_of_file; /* have we gotten any data yet? */
+} my_source_mgr;
+
+typedef my_source_mgr * my_src_ptr;
+
+#define INPUT_BUF_SIZE 4096 /* choose an efficiently fread'able size */
+
+
+/*
+ * Initialize source --- called by jpeg_read_header
+ * before any data is actually read.
+ */
+
+METHODDEF(void)
+init_source (j_decompress_ptr cinfo)
+{
+ my_src_ptr src = (my_src_ptr) cinfo->src;
+
+ /* We reset the empty-input-file flag for each image,
+ * but we don't clear the input buffer.
+ * This is correct behavior for reading a series of images from one source.
+ */
+ src->start_of_file = TRUE;
+}
+
+
+/*
+ * Fill the input buffer --- called whenever buffer is emptied.
+ *
+ * In typical applications, this should read fresh data into the buffer
+ * (ignoring the current state of next_input_byte & bytes_in_buffer),
+ * reset the pointer & count to the start of the buffer, and return TRUE
+ * indicating that the buffer has been reloaded. It is not necessary to
+ * fill the buffer entirely, only to obtain at least one more byte.
+ *
+ * There is no such thing as an EOF return. If the end of the file has been
+ * reached, the routine has a choice of ERREXIT() or inserting fake data into
+ * the buffer. In most cases, generating a warning message and inserting a
+ * fake EOI marker is the best course of action --- this will allow the
+ * decompressor to output however much of the image is there. However,
+ * the resulting error message is misleading if the real problem is an empty
+ * input file, so we handle that case specially.
+ *
+ * In applications that need to be able to suspend compression due to input
+ * not being available yet, a FALSE return indicates that no more data can be
+ * obtained right now, but more may be forthcoming later. In this situation,
+ * the decompressor will return to its caller (with an indication of the
+ * number of scanlines it has read, if any). The application should resume
+ * decompression after it has loaded more data into the input buffer. Note
+ * that there are substantial restrictions on the use of suspension --- see
+ * the documentation.
+ *
+ * When suspending, the decompressor will back up to a convenient restart point
+ * (typically the start of the current MCU). next_input_byte & bytes_in_buffer
+ * indicate where the restart point will be if the current call returns FALSE.
+ * Data beyond this point must be rescanned after resumption, so move it to
+ * the front of the buffer rather than discarding it.
+ */
+
+METHODDEF(boolean)
+fill_input_buffer (j_decompress_ptr cinfo)
+{
+ my_src_ptr src = (my_src_ptr) cinfo->src;
+ size_t nbytes;
+
+ nbytes = JFREAD(src->infile, src->buffer, INPUT_BUF_SIZE);
+
+ if (nbytes <= 0) {
+ if (src->start_of_file) /* Treat empty input file as fatal error */
+ ERREXIT(cinfo, JERR_INPUT_EMPTY);
+ WARNMS(cinfo, JWRN_JPEG_EOF);
+ /* Insert a fake EOI marker */
+ src->buffer[0] = (JOCTET) 0xFF;
+ src->buffer[1] = (JOCTET) JPEG_EOI;
+ nbytes = 2;
+ }
+
+ src->pub.next_input_byte = src->buffer;
+ src->pub.bytes_in_buffer = nbytes;
+ src->start_of_file = FALSE;
+
+ return TRUE;
+}
+
+
+/*
+ * Skip data --- used to skip over a potentially large amount of
+ * uninteresting data (such as an APPn marker).
+ *
+ * Writers of suspendable-input applications must note that skip_input_data
+ * is not granted the right to give a suspension return. If the skip extends
+ * beyond the data currently in the buffer, the buffer can be marked empty so
+ * that the next read will cause a fill_input_buffer call that can suspend.
+ * Arranging for additional bytes to be discarded before reloading the input
+ * buffer is the application writer's problem.
+ */
+
+METHODDEF(void)
+skip_input_data (j_decompress_ptr cinfo, long num_bytes)
+{
+ my_src_ptr src = (my_src_ptr) cinfo->src;
+
+ /* Just a dumb implementation for now. Could use fseek() except
+ * it doesn't work on pipes. Not clear that being smart is worth
+ * any trouble anyway --- large skips are infrequent.
+ */
+ if (num_bytes > 0) {
+ while (num_bytes > (long) src->pub.bytes_in_buffer) {
+ num_bytes -= (long) src->pub.bytes_in_buffer;
+ (void) fill_input_buffer(cinfo);
+ /* note we assume that fill_input_buffer will never return FALSE,
+ * so suspension need not be handled.
+ */
+ }
+ src->pub.next_input_byte += (size_t) num_bytes;
+ src->pub.bytes_in_buffer -= (size_t) num_bytes;
+ }
+}
+
+
+/*
+ * An additional method that can be provided by data source modules is the
+ * resync_to_restart method for error recovery in the presence of RST markers.
+ * For the moment, this source module just uses the default resync method
+ * provided by the JPEG library. That method assumes that no backtracking
+ * is possible.
+ */
+
+
+/*
+ * Terminate source --- called by jpeg_finish_decompress
+ * after all data has been read. Often a no-op.
+ *
+ * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
+ * application must deal with any cleanup that should happen even
+ * for error exit.
+ */
+
+METHODDEF(void)
+term_source (j_decompress_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work necessary here */
+}
+
+
+/*
+ * Prepare for input from a stdio stream.
+ * The caller must have already opened the stream, and is responsible
+ * for closing it after finishing decompression.
+ */
+
+GLOBAL(void)
+jpeg_stdio_src (j_decompress_ptr cinfo, FILE * infile)
+{
+ my_src_ptr src;
+
+ /* The source object and input buffer are made permanent so that a series
+ * of JPEG images can be read from the same file by calling jpeg_stdio_src
+ * only before the first one. (If we discarded the buffer at the end of
+ * one image, we'd likely lose the start of the next one.)
+ * This makes it unsafe to use this manager and a different source
+ * manager serially with the same JPEG object. Caveat programmer.
+ */
+ if (cinfo->src == NULL) { /* first time for this JPEG object? */
+ cinfo->src = (struct jpeg_source_mgr *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(my_source_mgr));
+ src = (my_src_ptr) cinfo->src;
+ src->buffer = (JOCTET *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ INPUT_BUF_SIZE * SIZEOF(JOCTET));
+ }
+
+ src = (my_src_ptr) cinfo->src;
+ src->pub.init_source = init_source;
+ src->pub.fill_input_buffer = fill_input_buffer;
+ src->pub.skip_input_data = skip_input_data;
+ src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
+ src->pub.term_source = term_source;
+ src->infile = infile;
+ src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
+ src->pub.next_input_byte = NULL; /* until buffer loaded */
+}
--- /dev/null
+/*
+ * jdcoefct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the coefficient buffer controller for decompression.
+ * This controller is the top level of the lossy JPEG decompressor proper.
+ * The coefficient buffer lies between entropy decoding and inverse-DCT steps.
+ *
+ * In buffered-image mode, this controller is the interface between
+ * input-oriented processing and output-oriented processing.
+ * Also, the input side (only) is used when reading a file for transcoding.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h"
+
+/* Block smoothing is only applicable for progressive JPEG, so: */
+#ifndef D_PROGRESSIVE_SUPPORTED
+#undef BLOCK_SMOOTHING_SUPPORTED
+#endif
+
+/* Private buffer controller object */
+
+typedef struct {
+ /* These variables keep track of the current location of the input side. */
+ /* cinfo->input_iMCU_row is also used for this. */
+ JDIMENSION MCU_ctr; /* counts MCUs processed in current row */
+ int MCU_vert_offset; /* counts MCU rows within iMCU row */
+ int MCU_rows_per_iMCU_row; /* number of such rows needed */
+
+ /* The output side's location is represented by cinfo->output_iMCU_row. */
+
+ /* In single-pass modes, it's sufficient to buffer just one MCU.
+ * We allocate a workspace of D_MAX_DATA_UNITS_IN_MCU coefficient blocks,
+ * and let the entropy decoder write into that workspace each time.
+ * (On 80x86, the workspace is FAR even though it's not really very big;
+ * this is to keep the module interfaces unchanged when a large coefficient
+ * buffer is necessary.)
+ * In multi-pass modes, this array points to the current MCU's blocks
+ * within the virtual arrays; it is used only by the input side.
+ */
+ JBLOCKROW MCU_buffer[D_MAX_DATA_UNITS_IN_MCU];
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+ /* In multi-pass modes, we need a virtual block array for each component. */
+ jvirt_barray_ptr whole_image[MAX_COMPONENTS];
+#endif
+
+#ifdef BLOCK_SMOOTHING_SUPPORTED
+ /* When doing block smoothing, we latch coefficient Al values here */
+ int * coef_bits_latch;
+#define SAVED_COEFS 6 /* we save coef_bits[0..5] */
+#endif
+} d_coef_controller;
+
+typedef d_coef_controller * d_coef_ptr;
+
+/* Forward declarations */
+METHODDEF(int) decompress_onepass
+ JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+METHODDEF(int) decompress_data
+ JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
+#endif
+#ifdef BLOCK_SMOOTHING_SUPPORTED
+LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo));
+METHODDEF(int) decompress_smooth_data
+ JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
+#endif
+
+
+LOCAL(void)
+start_iMCU_row (j_decompress_ptr cinfo)
+/* Reset within-iMCU-row counters for a new row (input side) */
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private;
+
+ /* In an interleaved scan, an MCU row is the same as an iMCU row.
+ * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
+ * But at the bottom of the image, process only what's left.
+ */
+ if (cinfo->comps_in_scan > 1) {
+ coef->MCU_rows_per_iMCU_row = 1;
+ } else {
+ if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
+ coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
+ else
+ coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
+ }
+
+ coef->MCU_ctr = 0;
+ coef->MCU_vert_offset = 0;
+}
+
+
+/*
+ * Initialize for an input processing pass.
+ */
+
+METHODDEF(void)
+start_input_pass (j_decompress_ptr cinfo)
+{
+ cinfo->input_iMCU_row = 0;
+ start_iMCU_row(cinfo);
+}
+
+
+/*
+ * Initialize for an output processing pass.
+ */
+
+METHODDEF(void)
+start_output_pass (j_decompress_ptr cinfo)
+{
+#ifdef BLOCK_SMOOTHING_SUPPORTED
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ /* d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private; */
+
+ /* If multipass, check to see whether to use block smoothing on this pass */
+ if (lossyd->coef_arrays != NULL) {
+ if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
+ lossyd->pub.decompress_data = decompress_smooth_data;
+ else
+ lossyd->pub.decompress_data = decompress_data;
+ }
+#endif
+ cinfo->output_iMCU_row = 0;
+}
+
+
+/*
+ * Decompress and return some data in the single-pass case.
+ * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
+ * Input and output must run in lockstep since we have only a one-MCU buffer.
+ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
+ *
+ * NB: output_buf contains a plane for each component in image,
+ * which we index according to the component's SOF position.
+ */
+
+METHODDEF(int)
+decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ int blkn, ci, xindex, yindex, yoffset, useful_width;
+ JSAMPARRAY output_ptr;
+ JDIMENSION start_col, output_col;
+ jpeg_component_info *compptr;
+ inverse_DCT_method_ptr inverse_DCT;
+
+ /* Loop to process as much as one whole iMCU row */
+ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
+ yoffset++) {
+ for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
+ MCU_col_num++) {
+ /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
+ jzero_far((void FAR *) coef->MCU_buffer[0],
+ (size_t) (cinfo->data_units_in_MCU * SIZEOF(JBLOCK)));
+ if (! (*lossyd->entropy_decode_mcu) (cinfo, coef->MCU_buffer)) {
+ /* Suspension forced; update state counters and exit */
+ coef->MCU_vert_offset = yoffset;
+ coef->MCU_ctr = MCU_col_num;
+ return JPEG_SUSPENDED;
+ }
+ /* Determine where data should go in output_buf and do the IDCT thing.
+ * We skip dummy blocks at the right and bottom edges (but blkn gets
+ * incremented past them!). Note the inner loop relies on having
+ * allocated the MCU_buffer[] blocks sequentially.
+ */
+ blkn = 0; /* index of current DCT block within MCU */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* Don't bother to IDCT an uninteresting component. */
+ if (! compptr->component_needed) {
+ blkn += compptr->MCU_data_units;
+ continue;
+ }
+ inverse_DCT = lossyd->inverse_DCT[compptr->component_index];
+ useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
+ : compptr->last_col_width;
+ output_ptr = output_buf[compptr->component_index] +
+ yoffset * compptr->codec_data_unit;
+ start_col = MCU_col_num * compptr->MCU_sample_width;
+ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
+ if (cinfo->input_iMCU_row < last_iMCU_row ||
+ yoffset+yindex < compptr->last_row_height) {
+ output_col = start_col;
+ for (xindex = 0; xindex < useful_width; xindex++) {
+ (*inverse_DCT) (cinfo, compptr,
+ (JCOEFPTR) coef->MCU_buffer[blkn+xindex],
+ output_ptr, output_col);
+ output_col += compptr->codec_data_unit;
+ }
+ }
+ blkn += compptr->MCU_width;
+ output_ptr += compptr->codec_data_unit;
+ }
+ }
+ }
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ coef->MCU_ctr = 0;
+ }
+ /* Completed the iMCU row, advance counters for next one */
+ cinfo->output_iMCU_row++;
+ if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
+ start_iMCU_row(cinfo);
+ return JPEG_ROW_COMPLETED;
+ }
+ /* Completed the scan */
+ (*cinfo->inputctl->finish_input_pass) (cinfo);
+ return JPEG_SCAN_COMPLETED;
+}
+
+
+/*
+ * Dummy consume-input routine for single-pass operation.
+ */
+
+METHODDEF(int)
+dummy_consume_data (j_decompress_ptr cinfo)
+{
+ (void)cinfo;
+ return JPEG_SUSPENDED; /* Always indicate nothing was done */
+}
+
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+
+/*
+ * Consume input data and store it in the full-image coefficient buffer.
+ * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
+ * ie, v_samp_factor block rows for each component in the scan.
+ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
+ */
+
+METHODDEF(int)
+consume_data (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ int blkn, ci, xindex, yindex, yoffset;
+ JDIMENSION start_col;
+ JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
+ JBLOCKROW buffer_ptr;
+ jpeg_component_info *compptr;
+
+ /* Align the virtual buffers for the components used in this scan. */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ buffer[ci] = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
+ cinfo->input_iMCU_row * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, TRUE);
+ /* Note: entropy decoder expects buffer to be zeroed,
+ * but this is handled automatically by the memory manager
+ * because we requested a pre-zeroed array.
+ */
+ }
+
+ /* Loop to process one whole iMCU row */
+ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
+ yoffset++) {
+ for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
+ MCU_col_num++) {
+ /* Construct list of pointers to DCT blocks belonging to this MCU */
+ blkn = 0; /* index of current DCT block within MCU */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ start_col = MCU_col_num * compptr->MCU_width;
+ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
+ buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
+ for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
+ coef->MCU_buffer[blkn++] = buffer_ptr++;
+ }
+ }
+ }
+ /* Try to fetch the MCU. */
+ if (! (*lossyd->entropy_decode_mcu) (cinfo, coef->MCU_buffer)) {
+ /* Suspension forced; update state counters and exit */
+ coef->MCU_vert_offset = yoffset;
+ coef->MCU_ctr = MCU_col_num;
+ return JPEG_SUSPENDED;
+ }
+ }
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ coef->MCU_ctr = 0;
+ }
+ /* Completed the iMCU row, advance counters for next one */
+ if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
+ start_iMCU_row(cinfo);
+ return JPEG_ROW_COMPLETED;
+ }
+ /* Completed the scan */
+ (*cinfo->inputctl->finish_input_pass) (cinfo);
+ return JPEG_SCAN_COMPLETED;
+}
+
+
+/*
+ * Decompress and return some data in the multi-pass case.
+ * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
+ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
+ *
+ * NB: output_buf contains a plane for each component in image.
+ */
+
+METHODDEF(int)
+decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ JDIMENSION block_num;
+ int ci, block_row, block_rows;
+ JBLOCKARRAY buffer;
+ JBLOCKROW buffer_ptr;
+ JSAMPARRAY output_ptr;
+ JDIMENSION output_col;
+ jpeg_component_info *compptr;
+ inverse_DCT_method_ptr inverse_DCT;
+
+ /* Force some input to be done if we are getting ahead of the input. */
+ while (cinfo->input_scan_number < cinfo->output_scan_number ||
+ (cinfo->input_scan_number == cinfo->output_scan_number &&
+ cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
+ if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
+ return JPEG_SUSPENDED;
+ }
+
+ /* OK, output from the virtual arrays. */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Don't bother to IDCT an uninteresting component. */
+ if (! compptr->component_needed)
+ continue;
+ /* Align the virtual buffer for this component. */
+ buffer = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[ci],
+ cinfo->output_iMCU_row * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, FALSE);
+ /* Count non-dummy DCT block rows in this iMCU row. */
+ if (cinfo->output_iMCU_row < last_iMCU_row)
+ block_rows = compptr->v_samp_factor;
+ else {
+ /* NB: can't use last_row_height here; it is input-side-dependent! */
+ block_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (block_rows == 0) block_rows = compptr->v_samp_factor;
+ }
+ inverse_DCT = lossyd->inverse_DCT[ci];
+ output_ptr = output_buf[ci];
+ /* Loop over all DCT blocks to be processed. */
+ for (block_row = 0; block_row < block_rows; block_row++) {
+ buffer_ptr = buffer[block_row];
+ output_col = 0;
+ for (block_num = 0; block_num < compptr->width_in_data_units; block_num++) {
+ (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr,
+ output_ptr, output_col);
+ buffer_ptr++;
+ output_col += compptr->codec_data_unit;
+ }
+ output_ptr += compptr->codec_data_unit;
+ }
+ }
+
+ if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
+ return JPEG_ROW_COMPLETED;
+ return JPEG_SCAN_COMPLETED;
+}
+
+#endif /* D_MULTISCAN_FILES_SUPPORTED */
+
+
+#ifdef BLOCK_SMOOTHING_SUPPORTED
+
+/*
+ * This code applies interblock smoothing as described by section K.8
+ * of the JPEG standard: the first 5 AC coefficients are estimated from
+ * the DC values of a DCT block and its 8 neighboring blocks.
+ * We apply smoothing only for progressive JPEG decoding, and only if
+ * the coefficients it can estimate are not yet known to full precision.
+ */
+
+/* Natural-order array positions of the first 5 zigzag-order coefficients */
+#define Q01_POS 1
+#define Q10_POS 8
+#define Q20_POS 16
+#define Q11_POS 9
+#define Q02_POS 2
+
+/*
+ * Determine whether block smoothing is applicable and safe.
+ * We also latch the current states of the coef_bits[] entries for the
+ * AC coefficients; otherwise, if the input side of the decompressor
+ * advances into a new scan, we might think the coefficients are known
+ * more accurately than they really are.
+ */
+
+LOCAL(boolean)
+smoothing_ok (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private;
+ boolean smoothing_useful = FALSE;
+ int ci, coefi;
+ jpeg_component_info *compptr;
+ JQUANT_TBL * qtable;
+ int * coef_bits;
+ int * coef_bits_latch;
+
+ if (! cinfo->process == JPROC_PROGRESSIVE || cinfo->coef_bits == NULL)
+ return FALSE;
+
+ /* Allocate latch area if not already done */
+ if (coef->coef_bits_latch == NULL)
+ coef->coef_bits_latch = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ cinfo->num_components *
+ (SAVED_COEFS * SIZEOF(int)));
+ coef_bits_latch = coef->coef_bits_latch;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* All components' quantization values must already be latched. */
+ if ((qtable = compptr->quant_table) == NULL)
+ return FALSE;
+ /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
+ if (qtable->quantval[0] == 0 ||
+ qtable->quantval[Q01_POS] == 0 ||
+ qtable->quantval[Q10_POS] == 0 ||
+ qtable->quantval[Q20_POS] == 0 ||
+ qtable->quantval[Q11_POS] == 0 ||
+ qtable->quantval[Q02_POS] == 0)
+ return FALSE;
+ /* DC values must be at least partly known for all components. */
+ coef_bits = cinfo->coef_bits[ci];
+ if (coef_bits[0] < 0)
+ return FALSE;
+ /* Block smoothing is helpful if some AC coefficients remain inaccurate. */
+ for (coefi = 1; coefi <= 5; coefi++) {
+ coef_bits_latch[coefi] = coef_bits[coefi];
+ if (coef_bits[coefi] != 0)
+ smoothing_useful = TRUE;
+ }
+ coef_bits_latch += SAVED_COEFS;
+ }
+
+ return smoothing_useful;
+}
+
+
+/*
+ * Variant of decompress_data for use when doing block smoothing.
+ */
+
+METHODDEF(int)
+decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef = (d_coef_ptr) lossyd->coef_private;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ JDIMENSION block_num, last_block_column;
+ int ci, block_row, block_rows, access_rows;
+ JBLOCKARRAY buffer;
+ JBLOCKROW buffer_ptr, prev_block_row, next_block_row;
+ JSAMPARRAY output_ptr;
+ JDIMENSION output_col;
+ jpeg_component_info *compptr;
+ inverse_DCT_method_ptr inverse_DCT;
+ boolean first_row, last_row;
+ JBLOCK workspace;
+ int *coef_bits;
+ JQUANT_TBL *quanttbl;
+ INT32 Q00,Q01,Q02,Q10,Q11,Q20, num;
+ int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9;
+ int Al, pred;
+
+ /* Force some input to be done if we are getting ahead of the input. */
+ while (cinfo->input_scan_number <= cinfo->output_scan_number &&
+ ! cinfo->inputctl->eoi_reached) {
+ if (cinfo->input_scan_number == cinfo->output_scan_number) {
+ /* If input is working on current scan, we ordinarily want it to
+ * have completed the current row. But if input scan is DC,
+ * we want it to keep one row ahead so that next block row's DC
+ * values are up to date.
+ */
+ JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0;
+ if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta)
+ break;
+ }
+ if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
+ return JPEG_SUSPENDED;
+ }
+
+ /* OK, output from the virtual arrays. */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Don't bother to IDCT an uninteresting component. */
+ if (! compptr->component_needed)
+ continue;
+ /* Count non-dummy DCT block rows in this iMCU row. */
+ if (cinfo->output_iMCU_row < last_iMCU_row) {
+ block_rows = compptr->v_samp_factor;
+ access_rows = block_rows * 2; /* this and next iMCU row */
+ last_row = FALSE;
+ } else {
+ /* NB: can't use last_row_height here; it is input-side-dependent! */
+ block_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (block_rows == 0) block_rows = compptr->v_samp_factor;
+ access_rows = block_rows; /* this iMCU row only */
+ last_row = TRUE;
+ }
+ /* Align the virtual buffer for this component. */
+ if (cinfo->output_iMCU_row > 0) {
+ access_rows += compptr->v_samp_factor; /* prior iMCU row too */
+ buffer = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[ci],
+ (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
+ (JDIMENSION) access_rows, FALSE);
+ buffer += compptr->v_samp_factor; /* point to current iMCU row */
+ first_row = FALSE;
+ } else {
+ buffer = (*cinfo->mem->access_virt_barray)
+ ((j_common_ptr) cinfo, coef->whole_image[ci],
+ (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
+ first_row = TRUE;
+ }
+ /* Fetch component-dependent info */
+ coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
+ quanttbl = compptr->quant_table;
+ Q00 = quanttbl->quantval[0];
+ Q01 = quanttbl->quantval[Q01_POS];
+ Q10 = quanttbl->quantval[Q10_POS];
+ Q20 = quanttbl->quantval[Q20_POS];
+ Q11 = quanttbl->quantval[Q11_POS];
+ Q02 = quanttbl->quantval[Q02_POS];
+ inverse_DCT = lossyd->inverse_DCT[ci];
+ output_ptr = output_buf[ci];
+ /* Loop over all DCT blocks to be processed. */
+ for (block_row = 0; block_row < block_rows; block_row++) {
+ buffer_ptr = buffer[block_row];
+ if (first_row && block_row == 0)
+ prev_block_row = buffer_ptr;
+ else
+ prev_block_row = buffer[block_row-1];
+ if (last_row && block_row == block_rows-1)
+ next_block_row = buffer_ptr;
+ else
+ next_block_row = buffer[block_row+1];
+ /* We fetch the surrounding DC values using a sliding-register approach.
+ * Initialize all nine here so as to do the right thing on narrow pics.
+ */
+ DC1 = DC2 = DC3 = (int) prev_block_row[0][0];
+ DC4 = DC5 = DC6 = (int) buffer_ptr[0][0];
+ DC7 = DC8 = DC9 = (int) next_block_row[0][0];
+ output_col = 0;
+ last_block_column = compptr->width_in_data_units - 1;
+ for (block_num = 0; block_num <= last_block_column; block_num++) {
+ /* Fetch current DCT block into workspace so we can modify it. */
+ jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
+ /* Update DC values */
+ if (block_num < last_block_column) {
+ DC3 = (int) prev_block_row[1][0];
+ DC6 = (int) buffer_ptr[1][0];
+ DC9 = (int) next_block_row[1][0];
+ }
+ /* Compute coefficient estimates per K.8.
+ * An estimate is applied only if coefficient is still zero,
+ * and is not known to be fully accurate.
+ */
+ /* AC01 */
+ if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) {
+ num = 36 * Q00 * (DC4 - DC6);
+ if (num >= 0) {
+ pred = (int) (((Q01<<7) + num) / (Q01<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ } else {
+ pred = (int) (((Q01<<7) - num) / (Q01<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ pred = -pred;
+ }
+ workspace[1] = (JCOEF) pred;
+ }
+ /* AC10 */
+ if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) {
+ num = 36 * Q00 * (DC2 - DC8);
+ if (num >= 0) {
+ pred = (int) (((Q10<<7) + num) / (Q10<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ } else {
+ pred = (int) (((Q10<<7) - num) / (Q10<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ pred = -pred;
+ }
+ workspace[8] = (JCOEF) pred;
+ }
+ /* AC20 */
+ if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) {
+ num = 9 * Q00 * (DC2 + DC8 - 2*DC5);
+ if (num >= 0) {
+ pred = (int) (((Q20<<7) + num) / (Q20<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ } else {
+ pred = (int) (((Q20<<7) - num) / (Q20<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ pred = -pred;
+ }
+ workspace[16] = (JCOEF) pred;
+ }
+ /* AC11 */
+ if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) {
+ num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
+ if (num >= 0) {
+ pred = (int) (((Q11<<7) + num) / (Q11<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ } else {
+ pred = (int) (((Q11<<7) - num) / (Q11<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ pred = -pred;
+ }
+ workspace[9] = (JCOEF) pred;
+ }
+ /* AC02 */
+ if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) {
+ num = 9 * Q00 * (DC4 + DC6 - 2*DC5);
+ if (num >= 0) {
+ pred = (int) (((Q02<<7) + num) / (Q02<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ } else {
+ pred = (int) (((Q02<<7) - num) / (Q02<<8));
+ if (Al > 0 && pred >= (1<<Al))
+ pred = (1<<Al)-1;
+ pred = -pred;
+ }
+ workspace[2] = (JCOEF) pred;
+ }
+ /* OK, do the IDCT */
+ (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace,
+ output_ptr, output_col);
+ /* Advance for next column */
+ DC1 = DC2; DC2 = DC3;
+ DC4 = DC5; DC5 = DC6;
+ DC7 = DC8; DC8 = DC9;
+ buffer_ptr++, prev_block_row++, next_block_row++;
+ output_col += compptr->codec_data_unit;
+ }
+ output_ptr += compptr->codec_data_unit;
+ }
+ }
+
+ if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
+ return JPEG_ROW_COMPLETED;
+ return JPEG_SCAN_COMPLETED;
+}
+
+#endif /* BLOCK_SMOOTHING_SUPPORTED */
+
+
+/*
+ * Initialize coefficient buffer controller.
+ */
+
+GLOBAL(void)
+jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ d_coef_ptr coef;
+
+ coef = (d_coef_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(d_coef_controller));
+ lossyd->coef_private = (void *) coef;
+ lossyd->coef_start_input_pass = start_input_pass;
+ lossyd->coef_start_output_pass = start_output_pass;
+#ifdef BLOCK_SMOOTHING_SUPPORTED
+ coef->coef_bits_latch = NULL;
+#endif
+
+ /* Create the coefficient buffer. */
+ if (need_full_buffer) {
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+ /* Allocate a full-image virtual array for each component, */
+ /* padded to a multiple of samp_factor DCT blocks in each direction. */
+ /* Note we ask for a pre-zeroed array. */
+ int ci, access_rows;
+ jpeg_component_info *compptr;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ access_rows = compptr->v_samp_factor;
+#ifdef BLOCK_SMOOTHING_SUPPORTED
+ /* If block smoothing could be used, need a bigger window */
+ if (cinfo->process == JPROC_PROGRESSIVE)
+ access_rows *= 3;
+#endif
+ coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) jround_up((long) compptr->height_in_data_units,
+ (long) compptr->v_samp_factor),
+ (JDIMENSION) access_rows);
+ }
+ lossyd->pub.consume_data = consume_data;
+ lossyd->pub.decompress_data = decompress_data;
+ lossyd->coef_arrays = coef->whole_image; /* link to virtual arrays */
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ /* We only need a single-MCU buffer. */
+ JBLOCKROW buffer;
+ int i;
+
+ buffer = (JBLOCKROW)
+ (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ D_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
+ for (i = 0; i < D_MAX_DATA_UNITS_IN_MCU; i++) {
+ coef->MCU_buffer[i] = buffer + i;
+ }
+ lossyd->pub.consume_data = dummy_consume_data;
+ lossyd->pub.decompress_data = decompress_onepass;
+ lossyd->coef_arrays = NULL; /* flag for no virtual arrays */
+ }
+}
--- /dev/null
+/*
+ * jdcolor.c
+ *
+ * Copyright (C) 1991-1997, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains output colorspace conversion routines.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_color_deconverter pub; /* public fields */
+
+ /* Private state for YCC->RGB conversion */
+ int * Cr_r_tab; /* => table for Cr to R conversion */
+ int * Cb_b_tab; /* => table for Cb to B conversion */
+ INT32 * Cr_g_tab; /* => table for Cr to G conversion */
+ INT32 * Cb_g_tab; /* => table for Cb to G conversion */
+} my_color_deconverter;
+
+typedef my_color_deconverter * my_cconvert_ptr;
+
+
+/**************** YCbCr -> RGB conversion: most common case **************/
+
+/*
+ * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
+ * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
+ * The conversion equations to be implemented are therefore
+ * R = Y + 1.40200 * Cr
+ * G = Y - 0.34414 * Cb - 0.71414 * Cr
+ * B = Y + 1.77200 * Cb
+ * where Cb and Cr represent the incoming values less CENTERJSAMPLE.
+ * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
+ *
+ * To avoid floating-point arithmetic, we represent the fractional constants
+ * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
+ * the products by 2^16, with appropriate rounding, to get the correct answer.
+ * Notice that Y, being an integral input, does not contribute any fraction
+ * so it need not participate in the rounding.
+ *
+ * For even more speed, we avoid doing any multiplications in the inner loop
+ * by precalculating the constants times Cb and Cr for all possible values.
+ * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
+ * for 12-bit samples it is still acceptable. It's not very reasonable for
+ * 16-bit samples, but if you want lossless storage you shouldn't be changing
+ * colorspace anyway.
+ * The Cr=>R and Cb=>B values can be rounded to integers in advance; the
+ * values for the G calculation are left scaled up, since we must add them
+ * together before rounding.
+ */
+
+#define SCALEBITS 16 /* speediest right-shift on some machines */
+#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
+#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
+
+
+/*
+ * Initialize tables for YCC->RGB colorspace conversion.
+ */
+
+LOCAL(void)
+build_ycc_rgb_table (j_decompress_ptr cinfo)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ int i;
+ INT32 x;
+#if BITS_IN_JSAMPLE == 16
+ /* no need for temporaries */
+#else
+ SHIFT_TEMPS
+#endif
+
+ cconvert->Cr_r_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ cconvert->Cb_b_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ cconvert->Cr_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+ cconvert->Cb_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+
+ for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
+ /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
+ /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
+
+#if BITS_IN_JSAMPLE == 16
+ /* Bug fix 2001-11-06 by Eichelberg: The integer routines below
+ produce an overflow when used with MAXJSAMPLE == 65535.
+ Use floating point calculation instead. */
+
+ /* Cr=>R value is nearest int to 1.40200 * x */
+ cconvert->Cr_r_tab[i] = (int)(1.40200 * (double)x + 0.5);
+ /* Cb=>B value is nearest int to 1.77200 * x */
+ cconvert->Cb_b_tab[i] = (int)(1.77200 * (double)x + 0.5);
+#else
+ /* Cr=>R value is nearest int to 1.40200 * x */
+ cconvert->Cr_r_tab[i] = (int)
+ RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
+ /* Cb=>B value is nearest int to 1.77200 * x */
+ cconvert->Cb_b_tab[i] = (int)
+ RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
+#endif
+
+ /* Cr=>G value is scaled-up -0.71414 * x */
+ cconvert->Cr_g_tab[i] = (- FIX(0.71414)) * x;
+ /* Cb=>G value is scaled-up -0.34414 * x */
+ /* We also add in ONE_HALF so that need not do it in inner loop */
+ cconvert->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF;
+ }
+}
+
+
+/*
+ * Convert some rows of samples to the output colorspace.
+ *
+ * Note that we change from noninterleaved, one-plane-per-component format
+ * to interleaved-pixel format. The output buffer is therefore three times
+ * as wide as the input buffer.
+ * A starting row offset is provided only for the input buffer. The caller
+ * can easily adjust the passed output_buf value to accommodate any row
+ * offset required on that side.
+ */
+
+METHODDEF(void)
+ycc_rgb_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int y, cb, cr;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+ /* copy these pointers into registers if possible */
+ register JSAMPLE * range_limit = cinfo->sample_range_limit;
+ register int * Crrtab = cconvert->Cr_r_tab;
+ register int * Cbbtab = cconvert->Cb_b_tab;
+ register INT32 * Crgtab = cconvert->Cr_g_tab;
+ register INT32 * Cbgtab = cconvert->Cb_g_tab;
+ SHIFT_TEMPS
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ y = GETJSAMPLE(inptr0[col]);
+ cb = GETJSAMPLE(inptr1[col]);
+ cr = GETJSAMPLE(inptr2[col]);
+ /* Range-limiting is essential due to noise introduced by DCT losses. */
+ outptr[RGB_RED] = range_limit[y + Crrtab[cr]];
+ outptr[RGB_GREEN] = range_limit[y +
+ ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
+ SCALEBITS))];
+ outptr[RGB_BLUE] = range_limit[y + Cbbtab[cb]];
+ outptr += RGB_PIXELSIZE;
+ }
+ }
+}
+
+
+/**************** Cases other than YCbCr -> RGB **************/
+
+
+/*
+ * Color conversion for no colorspace change: just copy the data,
+ * converting from separate-planes to interleaved representation.
+ */
+
+METHODDEF(void)
+null_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ register JSAMPROW inptr, outptr;
+ register JDIMENSION count;
+ register int num_components = cinfo->num_components;
+ JDIMENSION num_cols = cinfo->output_width;
+ int ci;
+
+ while (--num_rows >= 0) {
+ for (ci = 0; ci < num_components; ci++) {
+ inptr = input_buf[ci][input_row];
+ outptr = output_buf[0] + ci;
+ for (count = num_cols; count > 0; count--) {
+ *outptr = *inptr++; /* needn't bother with GETJSAMPLE() here */
+ outptr += num_components;
+ }
+ }
+ input_row++;
+ output_buf++;
+ }
+}
+
+
+/*
+ * Color conversion for grayscale: just copy the data.
+ * This also works for YCbCr -> grayscale conversion, in which
+ * we just copy the Y (luminance) component and ignore chrominance.
+ */
+
+METHODDEF(void)
+grayscale_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ jcopy_sample_rows(input_buf[0], (int) input_row, output_buf, 0,
+ num_rows, cinfo->output_width);
+}
+
+
+/*
+ * Convert grayscale to RGB: just duplicate the graylevel three times.
+ * This is provided to support applications that don't want to cope
+ * with grayscale as a separate case.
+ */
+
+METHODDEF(void)
+gray_rgb_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ register JSAMPROW inptr, outptr;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ inptr = input_buf[0][input_row++];
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ /* We can dispense with GETJSAMPLE() here */
+ outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col];
+ outptr += RGB_PIXELSIZE;
+ }
+ }
+}
+
+
+/*
+ * Adobe-style YCCK->CMYK conversion.
+ * We convert YCbCr to R=1-C, G=1-M, and B=1-Y using the same
+ * conversion as above, while passing K (black) unchanged.
+ * We assume build_ycc_rgb_table has been called.
+ */
+
+METHODDEF(void)
+ycck_cmyk_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int y, cb, cr;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2, inptr3;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+ /* copy these pointers into registers if possible */
+ register JSAMPLE * range_limit = cinfo->sample_range_limit;
+ register int * Crrtab = cconvert->Cr_r_tab;
+ register int * Cbbtab = cconvert->Cb_b_tab;
+ register INT32 * Crgtab = cconvert->Cr_g_tab;
+ register INT32 * Cbgtab = cconvert->Cb_g_tab;
+ SHIFT_TEMPS
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ inptr3 = input_buf[3][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ y = GETJSAMPLE(inptr0[col]);
+ cb = GETJSAMPLE(inptr1[col]);
+ cr = GETJSAMPLE(inptr2[col]);
+ /* Range-limiting is essential due to noise introduced by DCT losses. */
+ outptr[0] = range_limit[MAXJSAMPLE - (y + Crrtab[cr])]; /* red */
+ outptr[1] = range_limit[MAXJSAMPLE - (y + /* green */
+ ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
+ SCALEBITS)))];
+ outptr[2] = range_limit[MAXJSAMPLE - (y + Cbbtab[cb])]; /* blue */
+ /* K passes through unchanged */
+ outptr[3] = inptr3[col]; /* don't need GETJSAMPLE here */
+ outptr += 4;
+ }
+ }
+}
+
+
+/*
+ * Empty method for start_pass.
+ */
+
+METHODDEF(void)
+start_pass_dcolor (j_decompress_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work needed */
+}
+
+
+/*
+ * Module initialization routine for output colorspace conversion.
+ */
+
+GLOBAL(void)
+jinit_color_deconverter (j_decompress_ptr cinfo)
+{
+ my_cconvert_ptr cconvert;
+ int ci;
+
+ cconvert = (my_cconvert_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_color_deconverter));
+ cinfo->cconvert = (struct jpeg_color_deconverter *) cconvert;
+ cconvert->pub.start_pass = start_pass_dcolor;
+
+ /* Make sure num_components agrees with jpeg_color_space */
+ switch (cinfo->jpeg_color_space) {
+ case JCS_GRAYSCALE:
+ if (cinfo->num_components != 1)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+
+ case JCS_RGB:
+ case JCS_YCbCr:
+ if (cinfo->num_components != 3)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+
+ case JCS_CMYK:
+ case JCS_YCCK:
+ if (cinfo->num_components != 4)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+
+ default: /* JCS_UNKNOWN can be anything */
+ if (cinfo->num_components < 1)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+ }
+
+ /* Set out_color_components and conversion method based on requested space.
+ * Also clear the component_needed flags for any unused components,
+ * so that earlier pipeline stages can avoid useless computation.
+ */
+
+ switch (cinfo->out_color_space) {
+ case JCS_GRAYSCALE:
+ cinfo->out_color_components = 1;
+ if (cinfo->jpeg_color_space == JCS_GRAYSCALE ||
+ cinfo->jpeg_color_space == JCS_YCbCr) {
+ cconvert->pub.color_convert = grayscale_convert;
+ /* For color->grayscale conversion, only the Y (0) component is needed */
+ for (ci = 1; ci < cinfo->num_components; ci++)
+ cinfo->comp_info[ci].component_needed = FALSE;
+ } else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_RGB:
+ cinfo->out_color_components = RGB_PIXELSIZE;
+ if (cinfo->jpeg_color_space == JCS_YCbCr) {
+ cconvert->pub.color_convert = ycc_rgb_convert;
+ build_ycc_rgb_table(cinfo);
+ } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) {
+ cconvert->pub.color_convert = gray_rgb_convert;
+ } else if (cinfo->jpeg_color_space == JCS_RGB && RGB_PIXELSIZE == 3) {
+ cconvert->pub.color_convert = null_convert;
+ } else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_CMYK:
+ cinfo->out_color_components = 4;
+ if (cinfo->jpeg_color_space == JCS_YCCK) {
+ cconvert->pub.color_convert = ycck_cmyk_convert;
+ build_ycc_rgb_table(cinfo);
+ } else if (cinfo->jpeg_color_space == JCS_CMYK) {
+ cconvert->pub.color_convert = null_convert;
+ } else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ default:
+ /* Permit null conversion to same output space */
+ if (cinfo->out_color_space == cinfo->jpeg_color_space) {
+ cinfo->out_color_components = cinfo->num_components;
+ cconvert->pub.color_convert = null_convert;
+ } else /* unsupported non-null conversion */
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+ }
+
+ if (cinfo->quantize_colors)
+ cinfo->output_components = 1; /* single colormapped output component */
+ else
+ cinfo->output_components = cinfo->out_color_components;
+}
--- /dev/null
+/*
+ * jdct.h
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This include file contains common declarations for the forward and
+ * inverse DCT modules. These declarations are private to the DCT managers
+ * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
+ * The individual DCT algorithms are kept in separate files to ease
+ * machine-dependent tuning (e.g., assembly coding).
+ */
+
+
+/*
+ * A forward DCT routine is given a pointer to a work area of type DCTELEM[];
+ * the DCT is to be performed in-place in that buffer. Type DCTELEM is int
+ * for 8-bit samples, INT32 for 12-bit samples. (NOTE: Floating-point DCT
+ * implementations use an array of type FAST_FLOAT, instead.)
+ * The DCT inputs are expected to be signed (range +-CENTERJSAMPLE).
+ * The DCT outputs are returned scaled up by a factor of 8; they therefore
+ * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This
+ * convention improves accuracy in integer implementations and saves some
+ * work in floating-point ones.
+ * Quantization of the output coefficients is done by jcdctmgr.c.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+typedef int DCTELEM; /* 16 or 32 bits is fine */
+#else
+typedef INT32 DCTELEM; /* must have 32 bits */
+#endif
+
+typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data));
+typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data));
+
+
+/*
+ * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer
+ * to an output sample array. The routine must dequantize the input data as
+ * well as perform the IDCT; for dequantization, it uses the multiplier table
+ * pointed to by compptr->dct_table. The output data is to be placed into the
+ * sample array starting at a specified column. (Any row offset needed will
+ * be applied to the array pointer before it is passed to the IDCT code.)
+ * Note that the number of samples emitted by the IDCT routine is
+ * DCT_scaled_size * DCT_scaled_size.
+ */
+
+/* typedef inverse_DCT_method_ptr is declared in jpegint.h */
+
+/*
+ * Each IDCT routine has its own ideas about the best dct_table element type.
+ */
+
+typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
+#if BITS_IN_JSAMPLE == 8
+typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
+#define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */
+#else
+typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */
+#define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */
+#endif
+typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
+
+
+/*
+ * Each IDCT routine is responsible for range-limiting its results and
+ * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could
+ * be quite far out of range if the input data is corrupt, so a bulletproof
+ * range-limiting step is required. We use a mask-and-table-lookup method
+ * to do the combined operations quickly. See the comments with
+ * prepare_range_limit_table (in jdmaster.c) for more info.
+ */
+
+#define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE)
+
+#define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */
+
+
+/* Short forms of external names for systems with brain-damaged linkers. */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_fdct_islow jFDislow
+#define jpeg_fdct_ifast jFDifast
+#define jpeg_fdct_float jFDfloat
+#define jpeg_idct_islow jRDislow
+#define jpeg_idct_ifast jRDifast
+#define jpeg_idct_float jRDfloat
+#define jpeg_idct_4x4 jRD4x4
+#define jpeg_idct_2x2 jRD2x2
+#define jpeg_idct_1x1 jRD1x1
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+/* Extern declarations for the forward and inverse DCT routines. */
+
+EXTERN(void) jpeg_fdct_islow JPP((DCTELEM * data));
+EXTERN(void) jpeg_fdct_ifast JPP((DCTELEM * data));
+EXTERN(void) jpeg_fdct_float JPP((FAST_FLOAT * data));
+
+EXTERN(void) jpeg_idct_islow
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_ifast
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_float
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_4x4
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_2x2
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_1x1
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+
+
+/*
+ * Macros for handling fixed-point arithmetic; these are used by many
+ * but not all of the DCT/IDCT modules.
+ *
+ * All values are expected to be of type INT32.
+ * Fractional constants are scaled left by CONST_BITS bits.
+ * CONST_BITS is defined within each module using these macros,
+ * and may differ from one module to the next.
+ */
+
+#define ONE ((INT32) 1)
+#define CONST_SCALE (ONE << CONST_BITS)
+
+/* Convert a positive real constant to an integer scaled by CONST_SCALE.
+ * Caution: some C compilers fail to reduce "FIX(constant)" at compile time,
+ * thus causing a lot of useless floating-point operations at run time.
+ */
+
+#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5))
+
+/* Descale and correctly round an INT32 value that's scaled by N bits.
+ * We assume RIGHT_SHIFT rounds towards minus infinity, so adding
+ * the fudge factor is correct for either sign of X.
+ */
+
+#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
+
+/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
+ * This macro is used only when the two inputs will actually be no more than
+ * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
+ * full 32x32 multiply. This provides a useful speedup on many machines.
+ * Unfortunately there is no way to specify a 16x16->32 multiply portably
+ * in C, but some C compilers will do the right thing if you provide the
+ * correct combination of casts.
+ */
+
+#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
+#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const)))
+#endif
+#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
+#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const)))
+#endif
+
+#ifndef MULTIPLY16C16 /* default definition */
+#define MULTIPLY16C16(var,const) ((var) * (const))
+#endif
+
+/* Same except both inputs are variables. */
+
+#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
+#define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2)))
+#endif
+
+#ifndef MULTIPLY16V16 /* default definition */
+#define MULTIPLY16V16(var1,var2) ((var1) * (var2))
+#endif
--- /dev/null
+/*
+ * jddctmgr.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the inverse-DCT management logic.
+ * This code selects a particular IDCT implementation to be used,
+ * and it performs related housekeeping chores. No code in this file
+ * is executed per IDCT step, only during output pass setup.
+ *
+ * Note that the IDCT routines are responsible for performing coefficient
+ * dequantization as well as the IDCT proper. This module sets up the
+ * dequantization multiplier table needed by the IDCT routine.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy subsystem */
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+
+/*
+ * The decompressor input side (jdinput.c) saves away the appropriate
+ * quantization table for each component at the start of the first scan
+ * involving that component. (This is necessary in order to correctly
+ * decode files that reuse Q-table slots.)
+ * When we are ready to make an output pass, the saved Q-table is converted
+ * to a multiplier table that will actually be used by the IDCT routine.
+ * The multiplier table contents are IDCT-method-dependent. To support
+ * application changes in IDCT method between scans, we can remake the
+ * multiplier tables if necessary.
+ * In buffered-image mode, the first output pass may occur before any data
+ * has been seen for some components, and thus before their Q-tables have
+ * been saved away. To handle this case, multiplier tables are preset
+ * to zeroes; the result of the IDCT will be a neutral gray level.
+ */
+
+
+/* Private subobject for this module */
+
+typedef struct {
+ /* This array contains the IDCT method code that each multiplier table
+ * is currently set up for, or -1 if it's not yet set up.
+ * The actual multiplier tables are pointed to by dct_table in the
+ * per-component comp_info structures.
+ */
+ int cur_method[MAX_COMPONENTS];
+} idct_controller;
+
+typedef idct_controller * idct_ptr;
+
+
+/* Allocated multiplier tables: big enough for any supported variant */
+
+typedef union {
+ ISLOW_MULT_TYPE islow_array[DCTSIZE2];
+#ifdef DCT_IFAST_SUPPORTED
+ IFAST_MULT_TYPE ifast_array[DCTSIZE2];
+#endif
+#ifdef DCT_FLOAT_SUPPORTED
+ FLOAT_MULT_TYPE float_array[DCTSIZE2];
+#endif
+} multiplier_table;
+
+
+/* The current scaled-IDCT routines require ISLOW-style multiplier tables,
+ * so be sure to compile that code if either ISLOW or SCALING is requested.
+ */
+#ifdef DCT_ISLOW_SUPPORTED
+#define PROVIDE_ISLOW_TABLES
+#else
+#ifdef IDCT_SCALING_SUPPORTED
+#define PROVIDE_ISLOW_TABLES
+#endif
+#endif
+
+
+/*
+ * Prepare for an output pass.
+ * Here we select the proper IDCT routine for each component and build
+ * a matching multiplier table.
+ */
+
+METHODDEF(void)
+start_pass (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ idct_ptr idct = (idct_ptr) lossyd->idct_private;
+ int ci, i;
+ jpeg_component_info *compptr;
+ int method = 0;
+ inverse_DCT_method_ptr method_ptr = NULL;
+ JQUANT_TBL * qtbl;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Select the proper IDCT routine for this component's scaling */
+ switch (compptr->codec_data_unit) {
+#ifdef IDCT_SCALING_SUPPORTED
+ case 1:
+ method_ptr = jpeg_idct_1x1;
+ method = JDCT_ISLOW; /* jidctred uses islow-style table */
+ break;
+ case 2:
+ method_ptr = jpeg_idct_2x2;
+ method = JDCT_ISLOW; /* jidctred uses islow-style table */
+ break;
+ case 4:
+ method_ptr = jpeg_idct_4x4;
+ method = JDCT_ISLOW; /* jidctred uses islow-style table */
+ break;
+#endif
+ case DCTSIZE:
+ switch (cinfo->dct_method) {
+#ifdef DCT_ISLOW_SUPPORTED
+ case JDCT_ISLOW:
+ method_ptr = jpeg_idct_islow;
+ method = JDCT_ISLOW;
+ break;
+#endif
+#ifdef DCT_IFAST_SUPPORTED
+ case JDCT_IFAST:
+ method_ptr = jpeg_idct_ifast;
+ method = JDCT_IFAST;
+ break;
+#endif
+#ifdef DCT_FLOAT_SUPPORTED
+ case JDCT_FLOAT:
+ method_ptr = jpeg_idct_float;
+ method = JDCT_FLOAT;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+ break;
+ default:
+ ERREXIT1(cinfo, JERR_BAD_DCTSIZE, compptr->codec_data_unit);
+ break;
+ }
+ lossyd->inverse_DCT[ci] = method_ptr;
+ /* Create multiplier table from quant table.
+ * However, we can skip this if the component is uninteresting
+ * or if we already built the table. Also, if no quant table
+ * has yet been saved for the component, we leave the
+ * multiplier table all-zero; we'll be reading zeroes from the
+ * coefficient controller's buffer anyway.
+ */
+ if (! compptr->component_needed || idct->cur_method[ci] == method)
+ continue;
+ qtbl = compptr->quant_table;
+ if (qtbl == NULL) /* happens if no data yet for component */
+ continue;
+ idct->cur_method[ci] = method;
+ switch (method) {
+#ifdef PROVIDE_ISLOW_TABLES
+ case JDCT_ISLOW:
+ {
+ /* For LL&M IDCT method, multipliers are equal to raw quantization
+ * coefficients, but are stored as ints to ensure access efficiency.
+ */
+ ISLOW_MULT_TYPE * ismtbl = (ISLOW_MULT_TYPE *) compptr->dct_table;
+ for (i = 0; i < DCTSIZE2; i++) {
+ ismtbl[i] = (ISLOW_MULT_TYPE) qtbl->quantval[i];
+ }
+ }
+ break;
+#endif
+#ifdef DCT_IFAST_SUPPORTED
+ case JDCT_IFAST:
+ {
+ /* For AA&N IDCT method, multipliers are equal to quantization
+ * coefficients scaled by scalefactor[row]*scalefactor[col], where
+ * scalefactor[0] = 1
+ * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
+ * For integer operation, the multiplier table is to be scaled by
+ * IFAST_SCALE_BITS.
+ */
+ IFAST_MULT_TYPE * ifmtbl = (IFAST_MULT_TYPE *) compptr->dct_table;
+#define CONST_BITS 14
+ static const INT16 aanscales[DCTSIZE2] = {
+ /* precomputed values scaled up by 14 bits */
+ 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
+ 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270,
+ 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906,
+ 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315,
+ 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
+ 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552,
+ 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446,
+ 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247
+ };
+ SHIFT_TEMPS
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ ifmtbl[i] = (IFAST_MULT_TYPE)
+ DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
+ (INT32) aanscales[i]),
+ CONST_BITS-IFAST_SCALE_BITS);
+ }
+ }
+ break;
+#endif
+#ifdef DCT_FLOAT_SUPPORTED
+ case JDCT_FLOAT:
+ {
+ /* For float AA&N IDCT method, multipliers are equal to quantization
+ * coefficients scaled by scalefactor[row]*scalefactor[col], where
+ * scalefactor[0] = 1
+ * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
+ */
+ FLOAT_MULT_TYPE * fmtbl = (FLOAT_MULT_TYPE *) compptr->dct_table;
+ int row, col;
+ static const double aanscalefactor[DCTSIZE] = {
+ 1.0, 1.387039845, 1.306562965, 1.175875602,
+ 1.0, 0.785694958, 0.541196100, 0.275899379
+ };
+
+ i = 0;
+ for (row = 0; row < DCTSIZE; row++) {
+ for (col = 0; col < DCTSIZE; col++) {
+ fmtbl[i] = (FLOAT_MULT_TYPE)
+ ((double) qtbl->quantval[i] *
+ aanscalefactor[row] * aanscalefactor[col]);
+ i++;
+ }
+ }
+ }
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+ }
+}
+
+
+/*
+ * Initialize IDCT manager.
+ */
+
+GLOBAL(void)
+jinit_inverse_dct (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ idct_ptr idct;
+ int ci;
+ jpeg_component_info *compptr;
+
+ idct = (idct_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(idct_controller));
+ lossyd->idct_private = (void *) idct;
+ lossyd->idct_start_pass = start_pass;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Allocate and pre-zero a multiplier table for each component */
+ compptr->dct_table =
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(multiplier_table));
+ MEMZERO(compptr->dct_table, SIZEOF(multiplier_table));
+ /* Mark multiplier table not yet set up for any method */
+ idct->cur_method[ci] = -1;
+ }
+}
--- /dev/null
+/*
+ * jddiffct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the [un]difference buffer controller for decompression.
+ * This controller is the top level of the lossless JPEG decompressor proper.
+ * The difference buffer lies between the entropy decoding and
+ * prediction/undifferencing steps. The undifference buffer lies between the
+ * prediction/undifferencing and scaling steps.
+ *
+ * In buffered-image mode, this controller is the interface between
+ * input-oriented processing and output-oriented processing.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h"
+
+
+#ifdef D_LOSSLESS_SUPPORTED
+
+/* Private buffer controller object */
+
+typedef struct {
+ /* These variables keep track of the current location of the input side. */
+ /* cinfo->input_iMCU_row is also used for this. */
+ JDIMENSION MCU_ctr; /* counts MCUs processed in current row */
+ unsigned int restart_rows_to_go; /* MCU-rows left in this restart interval */
+ unsigned int MCU_vert_offset; /* counts MCU rows within iMCU row */
+ unsigned int MCU_rows_per_iMCU_row; /* number of such rows needed */
+
+ /* The output side's location is represented by cinfo->output_iMCU_row. */
+
+ JDIFFARRAY diff_buf[MAX_COMPONENTS]; /* iMCU row of differences */
+ JDIFFARRAY undiff_buf[MAX_COMPONENTS]; /* iMCU row of undiff'd samples */
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+ /* In multi-pass modes, we need a virtual sample array for each component. */
+ jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
+#endif
+} d_diff_controller;
+
+typedef d_diff_controller * d_diff_ptr;
+
+/* Forward declarations */
+METHODDEF(int) decompress_data
+ JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+METHODDEF(int) output_data
+ JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
+#endif
+
+
+LOCAL(void)
+start_iMCU_row (j_decompress_ptr cinfo)
+/* Reset within-iMCU-row counters for a new row (input side) */
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff = (d_diff_ptr) losslsd->diff_private;
+
+ /* In an interleaved scan, an MCU row is the same as an iMCU row.
+ * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
+ * But at the bottom of the image, process only what's left.
+ */
+ if (cinfo->comps_in_scan > 1) {
+ diff->MCU_rows_per_iMCU_row = 1;
+ } else {
+ if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
+ diff->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
+ else
+ diff->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
+ }
+
+ diff->MCU_ctr = 0;
+ diff->MCU_vert_offset = 0;
+}
+
+
+/*
+ * Initialize for an input processing pass.
+ */
+
+METHODDEF(void)
+start_input_pass (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff = (d_diff_ptr) losslsd->diff_private;
+
+ /* Check that the restart interval is an integer multiple of the number
+ * of MCU in an MCU-row.
+ */
+ if (cinfo->restart_interval % cinfo->MCUs_per_row != 0)
+ ERREXIT2(cinfo, JERR_BAD_RESTART,
+ cinfo->restart_interval, cinfo->MCUs_per_row);
+
+ /* Initialize restart counter */
+ diff->restart_rows_to_go = cinfo->restart_interval / cinfo->MCUs_per_row;
+
+ cinfo->input_iMCU_row = 0;
+ start_iMCU_row(cinfo);
+}
+
+
+/*
+ * Check for a restart marker & resynchronize decoder, undifferencer.
+ * Returns FALSE if must suspend.
+ */
+
+METHODDEF(boolean)
+process_restart (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff = (d_diff_ptr) losslsd->diff_private;
+
+ if (! (*losslsd->entropy_process_restart) (cinfo))
+ return FALSE;
+
+ (*losslsd->predict_process_restart) (cinfo);
+
+ /* Reset restart counter */
+ diff->restart_rows_to_go = cinfo->restart_interval / cinfo->MCUs_per_row;
+
+ return TRUE;
+}
+
+
+/*
+ * Initialize for an output processing pass.
+ */
+
+METHODDEF(void)
+start_output_pass (j_decompress_ptr cinfo)
+{
+ cinfo->output_iMCU_row = 0;
+}
+
+
+/*
+ * Decompress and return some data in the supplied buffer.
+ * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
+ * Input and output must run in lockstep since we have only a one-MCU buffer.
+ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
+ *
+ * NB: output_buf contains a plane for each component in image,
+ * which we index according to the component's SOF position.
+ */
+
+METHODDEF(int)
+decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff = (d_diff_ptr) losslsd->diff_private;
+ JDIMENSION MCU_col_num; /* index of current MCU within row */
+ JDIMENSION MCU_count; /* number of MCUs decoded */
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ int comp, ci, row, prev_row;
+ unsigned int yoffset;
+ jpeg_component_info *compptr;
+
+ /* Loop to process as much as one whole iMCU row */
+ for (yoffset = diff->MCU_vert_offset; yoffset < diff->MCU_rows_per_iMCU_row;
+ yoffset++) {
+
+ /* Process restart marker if needed; may have to suspend */
+ if (cinfo->restart_interval) {
+ if (diff->restart_rows_to_go == 0)
+ if (! process_restart(cinfo))
+ return JPEG_SUSPENDED;
+ }
+
+ MCU_col_num = diff->MCU_ctr;
+ /* Try to fetch an MCU-row (or remaining portion of suspended MCU-row). */
+ MCU_count =
+ (*losslsd->entropy_decode_mcus) (cinfo,
+ diff->diff_buf, yoffset, MCU_col_num,
+ cinfo->MCUs_per_row - MCU_col_num);
+ if (MCU_count != cinfo->MCUs_per_row - MCU_col_num) {
+ /* Suspension forced; update state counters and exit */
+ diff->MCU_vert_offset = yoffset;
+ diff->MCU_ctr += MCU_count;
+ return JPEG_SUSPENDED;
+ }
+
+ /* Account for restart interval (no-op if not using restarts) */
+ diff->restart_rows_to_go--;
+
+ /* Completed an MCU row, but perhaps not an iMCU row */
+ diff->MCU_ctr = 0;
+ }
+
+ /*
+ * Undifference and scale each scanline of the disassembled MCU-row
+ * separately. We do not process dummy samples at the end of a scanline
+ * or dummy rows at the end of the image.
+ */
+ for (comp = 0; comp < cinfo->comps_in_scan; comp++) {
+ compptr = cinfo->cur_comp_info[comp];
+ ci = compptr->component_index;
+ for (row = 0, prev_row = compptr->v_samp_factor - 1;
+ row < (cinfo->input_iMCU_row == last_iMCU_row ?
+ compptr->last_row_height : compptr->v_samp_factor);
+ prev_row = row, row++) {
+ (*losslsd->predict_undifference[ci]) (cinfo, ci,
+ diff->diff_buf[ci][row],
+ diff->undiff_buf[ci][prev_row],
+ diff->undiff_buf[ci][row],
+ compptr->width_in_data_units);
+ (*losslsd->scaler_scale) (cinfo, diff->undiff_buf[ci][row],
+ output_buf[ci][row],
+ compptr->width_in_data_units);
+ }
+ }
+
+ /* Completed the iMCU row, advance counters for next one.
+ *
+ * NB: output_data will increment output_iMCU_row.
+ * This counter is not needed for the single-pass case
+ * or the input side of the multi-pass case.
+ */
+ if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
+ start_iMCU_row(cinfo);
+ return JPEG_ROW_COMPLETED;
+ }
+ /* Completed the scan */
+ (*cinfo->inputctl->finish_input_pass) (cinfo);
+ return JPEG_SCAN_COMPLETED;
+}
+
+
+/*
+ * Dummy consume-input routine for single-pass operation.
+ */
+
+METHODDEF(int)
+dummy_consume_data (j_decompress_ptr cinfo)
+{
+ (void)cinfo;
+ return JPEG_SUSPENDED; /* Always indicate nothing was done */
+}
+
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+
+/*
+ * Consume input data and store it in the full-image sample buffer.
+ * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
+ * ie, v_samp_factor rows for each component in the scan.
+ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
+ */
+
+METHODDEF(int)
+consume_data (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff = (d_diff_ptr) losslsd->diff_private;
+ /* JDIMENSION MCU_col_num; */ /* index of current MCU within row */
+ /* JDIMENSION MCU_count; */ /* number of MCUs decoded */
+ /* JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; */
+ int comp, ci /* , yoffset, row, prev_row */;
+ JSAMPARRAY buffer[MAX_COMPS_IN_SCAN];
+ jpeg_component_info *compptr;
+
+ /* Align the virtual buffers for the components used in this scan. */
+ for (comp = 0; comp < cinfo->comps_in_scan; comp++) {
+ compptr = cinfo->cur_comp_info[comp];
+ ci = compptr->component_index;
+ buffer[ci] = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, diff->whole_image[ci],
+ cinfo->input_iMCU_row * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, TRUE);
+ }
+
+ return decompress_data(cinfo, buffer);
+}
+
+
+/*
+ * Output some data from the full-image buffer sample in the multi-pass case.
+ * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
+ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
+ *
+ * NB: output_buf contains a plane for each component in image.
+ */
+
+METHODDEF(int)
+output_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff = (d_diff_ptr) losslsd->diff_private;
+ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
+ int ci, samp_rows, row;
+ JSAMPARRAY buffer;
+ jpeg_component_info *compptr;
+
+ /* Force some input to be done if we are getting ahead of the input. */
+ while (cinfo->input_scan_number < cinfo->output_scan_number ||
+ (cinfo->input_scan_number == cinfo->output_scan_number &&
+ cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
+ if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
+ return JPEG_SUSPENDED;
+ }
+
+ /* OK, output from the virtual arrays. */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Align the virtual buffer for this component. */
+ buffer = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, diff->whole_image[ci],
+ cinfo->output_iMCU_row * compptr->v_samp_factor,
+ (JDIMENSION) compptr->v_samp_factor, FALSE);
+
+ if (cinfo->output_iMCU_row < last_iMCU_row)
+ samp_rows = compptr->v_samp_factor;
+ else {
+ /* NB: can't use last_row_height here; it is input-side-dependent! */
+ samp_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (samp_rows == 0) samp_rows = compptr->v_samp_factor;
+ }
+
+ for (row = 0; row < samp_rows; row++) {
+ MEMCOPY(output_buf[ci][row], buffer[row],
+ compptr->width_in_data_units * SIZEOF(JSAMPLE));
+ }
+ }
+
+ if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
+ return JPEG_ROW_COMPLETED;
+ return JPEG_SCAN_COMPLETED;
+}
+
+#endif /* D_MULTISCAN_FILES_SUPPORTED */
+
+
+/*
+ * Initialize difference buffer controller.
+ */
+
+GLOBAL(void)
+jinit_d_diff_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ d_diff_ptr diff;
+ int ci;
+ jpeg_component_info *compptr;
+
+ diff = (d_diff_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(d_diff_controller));
+ losslsd->diff_private = (void *) diff;
+ losslsd->diff_start_input_pass = start_input_pass;
+ losslsd->pub.start_output_pass = start_output_pass;
+
+ /* Create the [un]difference buffers. */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ diff->diff_buf[ci] = (*cinfo->mem->alloc_darray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) compptr->v_samp_factor);
+ diff->undiff_buf[ci] = (*cinfo->mem->alloc_darray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) compptr->v_samp_factor);
+ }
+
+ if (need_full_buffer) {
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+ /* Allocate a full-image virtual array for each component. */
+ int access_rows;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ access_rows = compptr->v_samp_factor;
+ diff->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
+ (JDIMENSION) jround_up((long) compptr->width_in_data_units,
+ (long) compptr->h_samp_factor),
+ (JDIMENSION) jround_up((long) compptr->height_in_data_units,
+ (long) compptr->v_samp_factor),
+ (JDIMENSION) access_rows);
+ }
+ losslsd->pub.consume_data = consume_data;
+ losslsd->pub.decompress_data = output_data;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ losslsd->pub.consume_data = dummy_consume_data;
+ losslsd->pub.decompress_data = decompress_data;
+ diff->whole_image[0] = NULL; /* flag for no virtual arrays */
+ }
+}
+
+#endif /* D_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jdhuff.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy decoding routines which are shared
+ * by the sequential, progressive and lossless decoders.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+#include "jlossls.h" /* Private declarations for lossless codec */
+#include "jdhuff.h" /* Declarations shared with jd*huff.c */
+
+
+/*
+ * Compute the derived values for a Huffman table.
+ * This routine also performs some validation checks on the table.
+ */
+
+GLOBAL(void)
+jpeg_make_d_derived_tbl (j_decompress_ptr cinfo, boolean isDC, int tblno,
+ d_derived_tbl ** pdtbl)
+{
+ JHUFF_TBL *htbl;
+ d_derived_tbl *dtbl;
+ int p, i, l, si, numsymbols;
+ int lookbits, ctr;
+ char huffsize[257];
+ unsigned int huffcode[257];
+ unsigned int code;
+
+ /* Note that huffsize[] and huffcode[] are filled in code-length order,
+ * paralleling the order of the symbols themselves in htbl->huffval[].
+ */
+
+ /* Find the input Huffman table */
+ if (tblno < 0 || tblno >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno);
+ htbl =
+ isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno];
+ if (htbl == NULL)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno);
+
+ /* Allocate a workspace if we haven't already done so. */
+ if (*pdtbl == NULL)
+ *pdtbl = (d_derived_tbl *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(d_derived_tbl));
+ dtbl = *pdtbl;
+ dtbl->pub = htbl; /* fill in back link */
+
+ /* Figure C.1: make table of Huffman code length for each symbol */
+
+ p = 0;
+ for (l = 1; l <= 16; l++) {
+ i = (int) htbl->bits[l];
+ if (i < 0 || p + i > 256) /* protect against table overrun */
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+ while (i--)
+ huffsize[p++] = (char) l;
+ }
+ huffsize[p] = 0;
+ numsymbols = p;
+
+ /* Figure C.2: generate the codes themselves */
+ /* We also validate that the counts represent a legal Huffman code tree. */
+
+ code = 0;
+ si = huffsize[0];
+ p = 0;
+ while (huffsize[p]) {
+ while (((int) huffsize[p]) == si) {
+ huffcode[p++] = code;
+ code++;
+ }
+ /* code is now 1 more than the last code used for codelength si; but
+ * it must still fit in si bits, since no code is allowed to be all ones.
+ * BUG FIX 2001-09-03: Comparison must be >, not >=
+ */
+ if (((INT32) code) > (((INT32) 1) << si))
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+ code <<= 1;
+ si++;
+ }
+
+ /* Figure F.15: generate decoding tables for bit-sequential decoding */
+
+ p = 0;
+ for (l = 1; l <= 16; l++) {
+ if (htbl->bits[l]) {
+ /* valoffset[l] = huffval[] index of 1st symbol of code length l,
+ * minus the minimum code of length l
+ */
+ dtbl->valoffset[l] = (INT32) p - (INT32) huffcode[p];
+ p += htbl->bits[l];
+ dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */
+ } else {
+ dtbl->maxcode[l] = -1; /* -1 if no codes of this length */
+ }
+ }
+ dtbl->maxcode[17] = 0xFFFFFL; /* ensures jpeg_huff_decode terminates */
+
+ /* Compute lookahead tables to speed up decoding.
+ * First we set all the table entries to 0, indicating "too long";
+ * then we iterate through the Huffman codes that are short enough and
+ * fill in all the entries that correspond to bit sequences starting
+ * with that code.
+ */
+
+ MEMZERO(dtbl->look_nbits, SIZEOF(dtbl->look_nbits));
+
+ p = 0;
+ for (l = 1; l <= HUFF_LOOKAHEAD; l++) {
+ for (i = 1; i <= (int) htbl->bits[l]; i++, p++) {
+ /* l = current code's length, p = its index in huffcode[] & huffval[]. */
+ /* Generate left-justified code followed by all possible bit sequences */
+ lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l);
+ for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--) {
+ dtbl->look_nbits[lookbits] = l;
+ dtbl->look_sym[lookbits] = htbl->huffval[p];
+ lookbits++;
+ }
+ }
+ }
+
+ /* Validate symbols as being reasonable.
+ * For AC tables, we make no check, but accept all byte values 0..255.
+ * For DC tables, we require the symbols to be in range 0..16.
+ * (Tighter bounds could be applied depending on the data depth and mode,
+ * but this is sufficient to ensure safe decoding.)
+ */
+ if (isDC) {
+ for (i = 0; i < numsymbols; i++) {
+ int sym = htbl->huffval[i];
+ if (sym < 0 || sym > 16)
+/* The following is needed to be able to read certain Philips DICOM MRI images */
+#if BITS_IN_JSAMPLE == 12
+ htbl->huffval[i]=15;
+#else
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+#endif /* BITS_IN_JSAMPLE == 12 */
+ }
+ }
+}
+
+
+/*
+ * Out-of-line code for bit fetching.
+ * See jdhuff.h for info about usage.
+ * Note: current values of get_buffer and bits_left are passed as parameters,
+ * but are returned in the corresponding fields of the state struct.
+ *
+ * On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width
+ * of get_buffer to be used. (On machines with wider words, an even larger
+ * buffer could be used.) However, on some machines 32-bit shifts are
+ * quite slow and take time proportional to the number of places shifted.
+ * (This is true with most PC compilers, for instance.) In this case it may
+ * be a win to set MIN_GET_BITS to the minimum value of 15. This reduces the
+ * average shift distance at the cost of more calls to jpeg_fill_bit_buffer.
+ */
+
+#ifdef SLOW_SHIFT_32
+#define MIN_GET_BITS 15 /* minimum allowable value */
+#else
+#define MIN_GET_BITS (BIT_BUF_SIZE-7)
+#endif
+
+
+GLOBAL(boolean)
+jpeg_fill_bit_buffer (bitread_working_state * state,
+ register bit_buf_type get_buffer, register int bits_left,
+ int nbits)
+/* Load up the bit buffer to a depth of at least nbits */
+{
+ /* Copy heavily used state fields into locals (hopefully registers) */
+ register const JOCTET * next_input_byte = state->next_input_byte;
+ register size_t bytes_in_buffer = state->bytes_in_buffer;
+ j_decompress_ptr cinfo = state->cinfo;
+
+ /* Attempt to load at least MIN_GET_BITS bits into get_buffer. */
+ /* (It is assumed that no request will be for more than that many bits.) */
+ /* We fail to do so only if we hit a marker or are forced to suspend. */
+
+ if (cinfo->unread_marker == 0) { /* cannot advance past a marker */
+ while (bits_left < MIN_GET_BITS) {
+ register int c;
+
+ /* Attempt to read a byte */
+ if (bytes_in_buffer == 0) {
+ if (! (*cinfo->src->fill_input_buffer) (cinfo))
+ return FALSE;
+ next_input_byte = cinfo->src->next_input_byte;
+ bytes_in_buffer = cinfo->src->bytes_in_buffer;
+ }
+ bytes_in_buffer--;
+ c = GETJOCTET(*next_input_byte++);
+
+ /* If it's 0xFF, check and discard stuffed zero byte */
+ if (c == 0xFF) {
+ /* Loop here to discard any padding FF's on terminating marker,
+ * so that we can save a valid unread_marker value. NOTE: we will
+ * accept multiple FF's followed by a 0 as meaning a single FF data
+ * byte. This data pattern is not valid according to the standard.
+ */
+ do {
+ if (bytes_in_buffer == 0) {
+ if (! (*cinfo->src->fill_input_buffer) (cinfo))
+ return FALSE;
+ next_input_byte = cinfo->src->next_input_byte;
+ bytes_in_buffer = cinfo->src->bytes_in_buffer;
+ }
+ bytes_in_buffer--;
+ c = GETJOCTET(*next_input_byte++);
+ } while (c == 0xFF);
+
+ if (c == 0) {
+ /* Found FF/00, which represents an FF data byte */
+ c = 0xFF;
+ } else {
+ /* Oops, it's actually a marker indicating end of compressed data.
+ * Save the marker code for later use.
+ * Fine point: it might appear that we should save the marker into
+ * bitread working state, not straight into permanent state. But
+ * once we have hit a marker, we cannot need to suspend within the
+ * current MCU, because we will read no more bytes from the data
+ * source. So it is OK to update permanent state right away.
+ */
+ cinfo->unread_marker = c;
+ /* See if we need to insert some fake zero bits. */
+ goto no_more_bytes;
+ }
+ }
+
+ /* OK, load c into get_buffer */
+ get_buffer = (get_buffer << 8) | c;
+ bits_left += 8;
+ } /* end while */
+ } else {
+ no_more_bytes:
+ /* We get here if we've read the marker that terminates the compressed
+ * data segment. There should be enough bits in the buffer register
+ * to satisfy the request; if so, no problem.
+ */
+ if (nbits > bits_left) {
+ /* Uh-oh. Report corrupted data to user and stuff zeroes into
+ * the data stream, so that we can produce some kind of image.
+ * We use a nonvolatile flag to ensure that only one warning message
+ * appears per data segment.
+ */
+ huffd_common_ptr huffd;
+ if (cinfo->process == JPROC_LOSSLESS)
+ huffd = (huffd_common_ptr) ((j_lossless_d_ptr) cinfo->codec)->entropy_private;
+ else
+ huffd = (huffd_common_ptr) ((j_lossy_d_ptr) cinfo->codec)->entropy_private;
+ if (! huffd->insufficient_data) {
+ WARNMS(cinfo, JWRN_HIT_MARKER);
+ huffd->insufficient_data = TRUE;
+ }
+ /* Fill the buffer with zero bits */
+ get_buffer <<= MIN_GET_BITS - bits_left;
+ bits_left = MIN_GET_BITS;
+ }
+ }
+
+ /* Unload the local registers */
+ state->next_input_byte = next_input_byte;
+ state->bytes_in_buffer = bytes_in_buffer;
+ state->get_buffer = get_buffer;
+ state->bits_left = bits_left;
+
+ return TRUE;
+}
+
+
+/*
+ * Out-of-line code for Huffman code decoding.
+ * See jdhuff.h for info about usage.
+ */
+
+GLOBAL(int)
+jpeg_huff_decode (bitread_working_state * state,
+ register bit_buf_type get_buffer, register int bits_left,
+ d_derived_tbl * htbl, int min_bits)
+{
+ register int l = min_bits;
+ register INT32 code;
+
+ /* HUFF_DECODE has determined that the code is at least min_bits */
+ /* bits long, so fetch that many bits in one swoop. */
+
+ CHECK_BIT_BUFFER(*state, l, return -1);
+ code = GET_BITS(l);
+
+ /* Collect the rest of the Huffman code one bit at a time. */
+ /* This is per Figure F.16 in the JPEG spec. */
+
+ while (code > htbl->maxcode[l]) {
+ code <<= 1;
+ CHECK_BIT_BUFFER(*state, 1, return -1);
+ code |= GET_BITS(1);
+ l++;
+ }
+
+ /* Unload the local registers */
+ state->get_buffer = get_buffer;
+ state->bits_left = bits_left;
+
+ /* With garbage input we may reach the sentinel value l = 17. */
+
+ if (l > 16) {
+ WARNMS(state->cinfo, JWRN_HUFF_BAD_CODE);
+ return 0; /* fake a zero as the safest result */
+ }
+
+ return htbl->pub->huffval[ (int) (code + htbl->valoffset[l]) ];
+}
--- /dev/null
+/*
+ * jdhuff.h
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains declarations for Huffman entropy decoding routines
+ * that are shared between the sequential decoder (jdhuff.c), the
+ * progressive decoder (jdphuff.c) and the lossless decoder (jdlhuff.c).
+ * No other modules need to see these.
+ */
+
+/* Short forms of external names for systems with brain-damaged linkers. */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_make_d_derived_tbl jMkDDerived
+#define jpeg_fill_bit_buffer jFilBitBuf
+#define jpeg_huff_decode jHufDecode
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+
+/* Derived data constructed for each Huffman table */
+
+#define HUFF_LOOKAHEAD 8 /* # of bits of lookahead */
+
+typedef struct {
+ /* Basic tables: (element [0] of each array is unused) */
+ INT32 maxcode[18]; /* largest code of length k (-1 if none) */
+ /* (maxcode[17] is a sentinel to ensure jpeg_huff_decode terminates) */
+ INT32 valoffset[17]; /* huffval[] offset for codes of length k */
+ /* valoffset[k] = huffval[] index of 1st symbol of code length k, less
+ * the smallest code of length k; so given a code of length k, the
+ * corresponding symbol is huffval[code + valoffset[k]]
+ */
+
+ /* Link to public Huffman table (needed only in jpeg_huff_decode) */
+ JHUFF_TBL *pub;
+
+ /* Lookahead tables: indexed by the next HUFF_LOOKAHEAD bits of
+ * the input data stream. If the next Huffman code is no more
+ * than HUFF_LOOKAHEAD bits long, we can obtain its length and
+ * the corresponding symbol directly from these tables.
+ */
+ int look_nbits[1<<HUFF_LOOKAHEAD]; /* # bits, or 0 if too long */
+ UINT8 look_sym[1<<HUFF_LOOKAHEAD]; /* symbol, or unused */
+} d_derived_tbl;
+
+/* Expand a Huffman table definition into the derived format */
+EXTERN(void) jpeg_make_d_derived_tbl
+ JPP((j_decompress_ptr cinfo, boolean isDC, int tblno,
+ d_derived_tbl ** pdtbl));
+
+
+/*
+ * Fetching the next N bits from the input stream is a time-critical operation
+ * for the Huffman decoders. We implement it with a combination of inline
+ * macros and out-of-line subroutines. Note that N (the number of bits
+ * demanded at one time) never exceeds 15 for JPEG use.
+ *
+ * We read source bytes into get_buffer and dole out bits as needed.
+ * If get_buffer already contains enough bits, they are fetched in-line
+ * by the macros CHECK_BIT_BUFFER and GET_BITS. When there aren't enough
+ * bits, jpeg_fill_bit_buffer is called; it will attempt to fill get_buffer
+ * as full as possible (not just to the number of bits needed; this
+ * prefetching reduces the overhead cost of calling jpeg_fill_bit_buffer).
+ * Note that jpeg_fill_bit_buffer may return FALSE to indicate suspension.
+ * On TRUE return, jpeg_fill_bit_buffer guarantees that get_buffer contains
+ * at least the requested number of bits --- dummy zeroes are inserted if
+ * necessary.
+ */
+
+typedef INT32 bit_buf_type; /* type of bit-extraction buffer */
+#define BIT_BUF_SIZE 32 /* size of buffer in bits */
+
+/* If long is > 32 bits on your machine, and shifting/masking longs is
+ * reasonably fast, making bit_buf_type be long and setting BIT_BUF_SIZE
+ * appropriately should be a win. Unfortunately we can't define the size
+ * with something like #define BIT_BUF_SIZE (sizeof(bit_buf_type)*8)
+ * because not all machines measure sizeof in 8-bit bytes.
+ */
+
+typedef struct { /* Bitreading state saved across MCUs */
+ bit_buf_type get_buffer; /* current bit-extraction buffer */
+ int bits_left; /* # of unused bits in it */
+} bitread_perm_state;
+
+typedef struct { /* Bitreading working state within an MCU */
+ /* Current data source location */
+ /* We need a copy, rather than munging the original, in case of suspension */
+ const JOCTET * next_input_byte; /* => next byte to read from source */
+ size_t bytes_in_buffer; /* # of bytes remaining in source buffer */
+ /* Bit input buffer --- note these values are kept in register variables,
+ * not in this struct, inside the inner loops.
+ */
+ bit_buf_type get_buffer; /* current bit-extraction buffer */
+ int bits_left; /* # of unused bits in it */
+ /* Pointer needed by jpeg_fill_bit_buffer. */
+ j_decompress_ptr cinfo; /* back link to decompress master record */
+} bitread_working_state;
+
+/* Macros to declare and load/save bitread local variables. */
+#define BITREAD_STATE_VARS \
+ register bit_buf_type get_buffer; \
+ register int bits_left; \
+ bitread_working_state br_state
+
+#define BITREAD_LOAD_STATE(cinfop,permstate) \
+ br_state.cinfo = cinfop; \
+ br_state.next_input_byte = cinfop->src->next_input_byte; \
+ br_state.bytes_in_buffer = cinfop->src->bytes_in_buffer; \
+ get_buffer = permstate.get_buffer; \
+ bits_left = permstate.bits_left;
+
+#define BITREAD_SAVE_STATE(cinfop,permstate) \
+ cinfop->src->next_input_byte = br_state.next_input_byte; \
+ cinfop->src->bytes_in_buffer = br_state.bytes_in_buffer; \
+ permstate.get_buffer = get_buffer; \
+ permstate.bits_left = bits_left
+
+/*
+ * These macros provide the in-line portion of bit fetching.
+ * Use CHECK_BIT_BUFFER to ensure there are N bits in get_buffer
+ * before using GET_BITS, PEEK_BITS, or DROP_BITS.
+ * The variables get_buffer and bits_left are assumed to be locals,
+ * but the state struct might not be (jpeg_huff_decode needs this).
+ * CHECK_BIT_BUFFER(state,n,action);
+ * Ensure there are N bits in get_buffer; if suspend, take action.
+ * val = GET_BITS(n);
+ * Fetch next N bits.
+ * val = PEEK_BITS(n);
+ * Fetch next N bits without removing them from the buffer.
+ * DROP_BITS(n);
+ * Discard next N bits.
+ * The value N should be a simple variable, not an expression, because it
+ * is evaluated multiple times.
+ */
+
+#define CHECK_BIT_BUFFER(state,nbits,action) \
+ { if (bits_left < (nbits)) { \
+ if (! jpeg_fill_bit_buffer(&(state),get_buffer,bits_left,nbits)) \
+ { action; } \
+ get_buffer = (state).get_buffer; bits_left = (state).bits_left; } }
+
+#define GET_BITS(nbits) \
+ (((int) (get_buffer >> (bits_left -= (nbits)))) & ((1<<(nbits))-1))
+
+#define PEEK_BITS(nbits) \
+ (((int) (get_buffer >> (bits_left - (nbits)))) & ((1<<(nbits))-1))
+
+#define DROP_BITS(nbits) \
+ (bits_left -= (nbits))
+
+/* Load up the bit buffer to a depth of at least nbits */
+EXTERN(boolean) jpeg_fill_bit_buffer
+ JPP((bitread_working_state * state, register bit_buf_type get_buffer,
+ register int bits_left, int nbits));
+
+
+/*
+ * Code for extracting next Huffman-coded symbol from input bit stream.
+ * Again, this is time-critical and we make the main paths be macros.
+ *
+ * We use a lookahead table to process codes of up to HUFF_LOOKAHEAD bits
+ * without looping. Usually, more than 95% of the Huffman codes will be 8
+ * or fewer bits long. The few overlength codes are handled with a loop,
+ * which need not be inline code.
+ *
+ * Notes about the HUFF_DECODE macro:
+ * 1. Near the end of the data segment, we may fail to get enough bits
+ * for a lookahead. In that case, we do it the hard way.
+ * 2. If the lookahead table contains no entry, the next code must be
+ * more than HUFF_LOOKAHEAD bits long.
+ * 3. jpeg_huff_decode returns -1 if forced to suspend.
+ */
+
+#define HUFF_DECODE(result,state,htbl,failaction,slowlabel) \
+{ register int nb, look; \
+ if (bits_left < HUFF_LOOKAHEAD) { \
+ if (! jpeg_fill_bit_buffer(&state,get_buffer,bits_left, 0)) {failaction;} \
+ get_buffer = state.get_buffer; bits_left = state.bits_left; \
+ if (bits_left < HUFF_LOOKAHEAD) { \
+ nb = 1; goto slowlabel; \
+ } \
+ } \
+ look = PEEK_BITS(HUFF_LOOKAHEAD); \
+ if ((nb = htbl->look_nbits[look]) != 0) { \
+ DROP_BITS(nb); \
+ result = htbl->look_sym[look]; \
+ } else { \
+ nb = HUFF_LOOKAHEAD+1; \
+slowlabel: \
+ if ((result=jpeg_huff_decode(&state,get_buffer,bits_left,htbl,nb)) < 0) \
+ { failaction; } \
+ get_buffer = state.get_buffer; bits_left = state.bits_left; \
+ } \
+}
+
+/* Out-of-line case for Huffman code fetching */
+EXTERN(int) jpeg_huff_decode
+ JPP((bitread_working_state * state, register bit_buf_type get_buffer,
+ register int bits_left, d_derived_tbl * htbl, int min_bits));
+
+
+/* Common fields between sequential, progressive and lossless Huffman entropy
+ * decoder master structs.
+ */
+
+#define huffd_common_fields \
+ boolean insufficient_data; /* set TRUE after emmitting warning */ \
+ /* These fields are loaded into local variables at start of each MCU. \
+ * In case of suspension, we exit WITHOUT updating them. \
+ */ \
+ bitread_perm_state bitstate /* Bit buffer at start of MCU */
+
+/* Routines that are to be used by any or all of the entropy decoders are
+ * declared to receive a pointer to this structure. There are no actual
+ * instances of huffd_common_struct, only of shuff_entropy_decoder,
+ * phuff_entropy_decoder and lhuff_entropy_decoder.
+ */
+struct huffd_common_struct {
+ huffd_common_fields; /* Fields common to all decoder struct types */
+ /* Additional fields follow in an actual shuff_entropy_decoder,
+ * phuff_entropy_decoder or lhuff_entropy_decoder struct. All four structs
+ * must agree on these initial fields! (This would be a lot cleaner in C++.)
+ */
+};
+
+typedef struct huffd_common_struct * huffd_common_ptr;
--- /dev/null
+/*
+ * jdinput.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains input control logic for the JPEG decompressor.
+ * These routines are concerned with controlling the decompressor's input
+ * processing (marker reading and coefficient/difference decoding).
+ * The actual input reading is done in jdmarker.c, jdhuff.c, jdphuff.c,
+ * and jdlhuff.c.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private state */
+
+typedef struct {
+ struct jpeg_input_controller pub; /* public fields */
+
+ boolean inheaders; /* TRUE until first SOS is reached */
+} my_input_controller;
+
+typedef my_input_controller * my_inputctl_ptr;
+
+
+/* Forward declarations */
+METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
+
+
+/*
+ * Routines to calculate various quantities related to the size of the image.
+ */
+
+LOCAL(void)
+initial_setup (j_decompress_ptr cinfo)
+/* Called once, when first SOS marker is reached */
+{
+ int ci;
+ jpeg_component_info *compptr;
+
+ /* Make sure image isn't bigger than I can handle */
+ if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
+ (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
+ ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
+
+ if (cinfo->process == JPROC_LOSSLESS) {
+ /* If precision > compiled-in value, we must downscale */
+ if (cinfo->data_precision > BITS_IN_JSAMPLE)
+ WARNMS2(cinfo, JWRN_MUST_DOWNSCALE,
+ cinfo->data_precision, BITS_IN_JSAMPLE);
+ }
+ else { /* Lossy processes */
+ /* For now, precision must match compiled-in value... */
+ if (cinfo->data_precision != BITS_IN_JSAMPLE)
+ ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
+ }
+
+ /* Check that number of components won't exceed internal array sizes */
+ if (cinfo->num_components > MAX_COMPONENTS)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
+ MAX_COMPONENTS);
+
+ /* Compute maximum sampling factors; check factor validity */
+ cinfo->max_h_samp_factor = 1;
+ cinfo->max_v_samp_factor = 1;
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
+ compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
+ ERREXIT(cinfo, JERR_BAD_SAMPLING);
+ cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
+ compptr->h_samp_factor);
+ cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
+ compptr->v_samp_factor);
+ }
+
+ /* We initialize codec_data_unit and min_codec_data_unit to data_unit.
+ * In the full decompressor, this will be overridden by jdmaster.c;
+ * but in the transcoder, jdmaster.c is not used, so we must do it here.
+ */
+ cinfo->min_codec_data_unit = cinfo->data_unit;
+
+ /* Compute dimensions of components */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ compptr->codec_data_unit = cinfo->data_unit;
+ /* Size in data units */
+ compptr->width_in_data_units = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+ (long) (cinfo->max_h_samp_factor * cinfo->data_unit));
+ compptr->height_in_data_units = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+ (long) (cinfo->max_v_samp_factor * cinfo->data_unit));
+ /* downsampled_width and downsampled_height will also be overridden by
+ * jdmaster.c if we are doing full decompression. The transcoder library
+ * doesn't use these values, but the calling application might.
+ */
+ /* Size in samples */
+ compptr->downsampled_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+ (long) cinfo->max_h_samp_factor);
+ compptr->downsampled_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+ (long) cinfo->max_v_samp_factor);
+ /* Mark component needed, until color conversion says otherwise */
+ compptr->component_needed = TRUE;
+ /* Mark no quantization table yet saved for component */
+ compptr->quant_table = NULL;
+ }
+
+ /* Compute number of fully interleaved MCU rows. */
+ cinfo->total_iMCU_rows = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height,
+ (long) (cinfo->max_v_samp_factor*cinfo->data_unit));
+
+ /* Decide whether file contains multiple scans */
+ if (cinfo->comps_in_scan < cinfo->num_components ||
+ cinfo->process == JPROC_PROGRESSIVE)
+ cinfo->inputctl->has_multiple_scans = TRUE;
+ else
+ cinfo->inputctl->has_multiple_scans = FALSE;
+}
+
+
+LOCAL(void)
+per_scan_setup (j_decompress_ptr cinfo)
+/* Do computations that are needed before processing a JPEG scan */
+/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
+{
+ int ci, mcublks, tmp;
+ jpeg_component_info *compptr;
+
+ if (cinfo->comps_in_scan == 1) {
+
+ /* Noninterleaved (single-component) scan */
+ compptr = cinfo->cur_comp_info[0];
+
+ /* Overall image size in MCUs */
+ cinfo->MCUs_per_row = compptr->width_in_data_units;
+ cinfo->MCU_rows_in_scan = compptr->height_in_data_units;
+
+ /* For noninterleaved scan, always one data unit per MCU */
+ compptr->MCU_width = 1;
+ compptr->MCU_height = 1;
+ compptr->MCU_data_units = 1;
+ compptr->MCU_sample_width = compptr->codec_data_unit;
+ compptr->last_col_width = 1;
+ /* For noninterleaved scans, it is convenient to define last_row_height
+ * as the number of data unit rows present in the last iMCU row.
+ */
+ tmp = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
+ if (tmp == 0) tmp = compptr->v_samp_factor;
+ compptr->last_row_height = tmp;
+
+ /* Prepare array describing MCU composition */
+ cinfo->data_units_in_MCU = 1;
+ cinfo->MCU_membership[0] = 0;
+
+ } else {
+
+ /* Interleaved (multi-component) scan */
+ if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
+ MAX_COMPS_IN_SCAN);
+
+ /* Overall image size in MCUs */
+ cinfo->MCUs_per_row = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width,
+ (long) (cinfo->max_h_samp_factor*cinfo->data_unit));
+ cinfo->MCU_rows_in_scan = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height,
+ (long) (cinfo->max_v_samp_factor*cinfo->data_unit));
+
+ cinfo->data_units_in_MCU = 0;
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* Sampling factors give # of data units of component in each MCU */
+ compptr->MCU_width = compptr->h_samp_factor;
+ compptr->MCU_height = compptr->v_samp_factor;
+ compptr->MCU_data_units = compptr->MCU_width * compptr->MCU_height;
+ compptr->MCU_sample_width = compptr->MCU_width * compptr->codec_data_unit;
+ /* Figure number of non-dummy data units in last MCU column & row */
+ tmp = (int) (compptr->width_in_data_units % compptr->MCU_width);
+ if (tmp == 0) tmp = compptr->MCU_width;
+ compptr->last_col_width = tmp;
+ tmp = (int) (compptr->height_in_data_units % compptr->MCU_height);
+ if (tmp == 0) tmp = compptr->MCU_height;
+ compptr->last_row_height = tmp;
+ /* Prepare array describing MCU composition */
+ mcublks = compptr->MCU_data_units;
+ if (cinfo->data_units_in_MCU + mcublks > D_MAX_DATA_UNITS_IN_MCU)
+ ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
+ while (mcublks-- > 0) {
+ cinfo->MCU_membership[cinfo->data_units_in_MCU++] = ci;
+ }
+ }
+
+ }
+}
+
+
+/*
+ * Initialize the input modules to read a scan of compressed data.
+ * The first call to this is done by jdmaster.c after initializing
+ * the entire decompressor (during jpeg_start_decompress).
+ * Subsequent calls come from consume_markers, below.
+ */
+
+METHODDEF(void)
+start_input_pass (j_decompress_ptr cinfo)
+{
+ per_scan_setup(cinfo);
+ (*cinfo->codec->start_input_pass) (cinfo);
+ cinfo->inputctl->consume_input = cinfo->codec->consume_data;
+}
+
+
+/*
+ * Finish up after inputting a compressed-data scan.
+ * This is called by the coefficient controller after it's read all
+ * the expected data of the scan.
+ */
+
+METHODDEF(void)
+finish_input_pass (j_decompress_ptr cinfo)
+{
+ cinfo->inputctl->consume_input = consume_markers;
+}
+
+
+/*
+ * Read JPEG markers before, between, or after compressed-data scans.
+ * Change state as necessary when a new scan is reached.
+ * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
+ *
+ * The consume_input method pointer points either here or to the
+ * coefficient controller's consume_data routine, depending on whether
+ * we are reading a compressed data segment or inter-segment markers.
+ */
+
+METHODDEF(int)
+consume_markers (j_decompress_ptr cinfo)
+{
+ my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
+ int val;
+
+ if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
+ return JPEG_REACHED_EOI;
+
+ val = (*cinfo->marker->read_markers) (cinfo);
+
+ switch (val) {
+ case JPEG_REACHED_SOS: /* Found SOS */
+ if (inputctl->inheaders) { /* 1st SOS */
+ initial_setup(cinfo);
+ /*
+ * Initialize the decompression codec. We need to do this here so that
+ * any codec-specific fields and function pointers are available to
+ * the rest of the library.
+ */
+ jinit_d_codec(cinfo);
+ inputctl->inheaders = FALSE;
+ /* Note: start_input_pass must be called by jdmaster.c
+ * before any more input can be consumed. jdapimin.c is
+ * responsible for enforcing this sequencing.
+ */
+ } else { /* 2nd or later SOS marker */
+ if (! inputctl->pub.has_multiple_scans)
+ ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
+ start_input_pass(cinfo);
+ }
+ break;
+ case JPEG_REACHED_EOI: /* Found EOI */
+ inputctl->pub.eoi_reached = TRUE;
+ if (inputctl->inheaders) { /* Tables-only datastream, apparently */
+ if (cinfo->marker->saw_SOF)
+ ERREXIT(cinfo, JERR_SOF_NO_SOS);
+ } else {
+ /* Prevent infinite loop in coef ctlr's decompress_data routine
+ * if user set output_scan_number larger than number of scans.
+ */
+ if (cinfo->output_scan_number > cinfo->input_scan_number)
+ cinfo->output_scan_number = cinfo->input_scan_number;
+ }
+ break;
+ case JPEG_SUSPENDED:
+ break;
+ }
+
+ return val;
+}
+
+
+/*
+ * Reset state to begin a fresh datastream.
+ */
+
+METHODDEF(void)
+reset_input_controller (j_decompress_ptr cinfo)
+{
+ my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
+
+ inputctl->pub.consume_input = consume_markers;
+ inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
+ inputctl->pub.eoi_reached = FALSE;
+ inputctl->inheaders = TRUE;
+ /* Reset other modules */
+ (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
+ (*cinfo->marker->reset_marker_reader) (cinfo);
+ /* Reset progression state -- would be cleaner if entropy decoder did this */
+ cinfo->coef_bits = NULL;
+}
+
+
+/*
+ * Initialize the input controller module.
+ * This is called only once, when the decompression object is created.
+ */
+
+GLOBAL(void)
+jinit_input_controller (j_decompress_ptr cinfo)
+{
+ my_inputctl_ptr inputctl;
+
+ /* Create subobject in permanent pool */
+ inputctl = (my_inputctl_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(my_input_controller));
+ cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
+ /* Initialize method pointers */
+ inputctl->pub.consume_input = consume_markers;
+ inputctl->pub.reset_input_controller = reset_input_controller;
+ inputctl->pub.start_input_pass = start_input_pass;
+ inputctl->pub.finish_input_pass = finish_input_pass;
+ /* Initialize state: can't use reset_input_controller since we don't
+ * want to try to reset other modules yet.
+ */
+ inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
+ inputctl->pub.eoi_reached = FALSE;
+ inputctl->inheaders = TRUE;
+}
--- /dev/null
+/*
+ * jdlhuff.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy decoding routines for lossless JPEG.
+ *
+ * Much of the complexity here has to do with supporting input suspension.
+ * If the data source module demands suspension, we want to be able to back
+ * up to the start of the current MCU. To do this, we copy state variables
+ * into local working storage, and update them back to the permanent
+ * storage only upon successful completion of an MCU.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+#include "jdhuff.h" /* Declarations shared with jd*huff.c */
+
+
+#ifdef D_LOSSLESS_SUPPORTED
+
+typedef struct {
+ int ci, yoffset, MCU_width;
+} lhd_output_ptr_info;
+
+/*
+ * Private entropy decoder object for lossless Huffman decoding.
+ */
+
+typedef struct {
+ huffd_common_fields; /* Fields shared with other entropy decoders */
+
+ /* Pointers to derived tables (these workspaces have image lifespan) */
+ d_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
+
+ /* Precalculated info set up by start_pass for use in decode_mcus: */
+
+ /* Pointers to derived tables to be used for each data unit within an MCU */
+ d_derived_tbl * cur_tbls[D_MAX_DATA_UNITS_IN_MCU];
+
+ /* Pointers to the proper output difference row for each group of data units
+ * within an MCU. For each component, there are Vi groups of Hi data units.
+ */
+ JDIFFROW output_ptr[D_MAX_DATA_UNITS_IN_MCU];
+
+ /* Number of output pointers in use for the current MCU. This is the sum
+ * of all Vi in the MCU.
+ */
+ int num_output_ptrs;
+
+ /* Information used for positioning the output pointers within the output
+ * difference rows.
+ */
+ lhd_output_ptr_info output_ptr_info[D_MAX_DATA_UNITS_IN_MCU];
+
+ /* Index of the proper output pointer for each data unit within an MCU */
+ int output_ptr_index[D_MAX_DATA_UNITS_IN_MCU];
+
+} lhuff_entropy_decoder;
+
+typedef lhuff_entropy_decoder * lhuff_entropy_ptr;
+
+
+/*
+ * Initialize for a Huffman-compressed scan.
+ */
+
+METHODDEF(void)
+start_pass_lhuff_decoder (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsd->entropy_private;
+ int ci, dctbl, sampn, ptrn, yoffset, xoffset;
+ jpeg_component_info * compptr;
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ dctbl = compptr->dc_tbl_no;
+ /* Make sure requested tables are present */
+ if (dctbl < 0 || dctbl >= NUM_HUFF_TBLS ||
+ cinfo->dc_huff_tbl_ptrs[dctbl] == NULL)
+ ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, dctbl);
+ /* Compute derived values for Huffman tables */
+ /* We may do this more than once for a table, but it's not expensive */
+ jpeg_make_d_derived_tbl(cinfo, TRUE, dctbl,
+ & entropy->derived_tbls[dctbl]);
+ }
+
+ /* Precalculate decoding info for each sample in an MCU of this scan */
+ for (sampn = 0, ptrn = 0; sampn < cinfo->data_units_in_MCU;) {
+ compptr = cinfo->cur_comp_info[cinfo->MCU_membership[sampn]];
+ ci = compptr->component_index;
+ for (yoffset = 0; yoffset < compptr->MCU_height; yoffset++, ptrn++) {
+ /* Precalculate the setup info for each output pointer */
+ entropy->output_ptr_info[ptrn].ci = ci;
+ entropy->output_ptr_info[ptrn].yoffset = yoffset;
+ entropy->output_ptr_info[ptrn].MCU_width = compptr->MCU_width;
+ for (xoffset = 0; xoffset < compptr->MCU_width; xoffset++, sampn++) {
+ /* Precalculate the output pointer index for each sample */
+ entropy->output_ptr_index[sampn] = ptrn;
+ /* Precalculate which table to use for each sample */
+ entropy->cur_tbls[sampn] = entropy->derived_tbls[compptr->dc_tbl_no];
+ }
+ }
+ }
+ entropy->num_output_ptrs = ptrn;
+
+ /* Initialize bitread state variables */
+ entropy->bitstate.bits_left = 0;
+ entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */
+ entropy->insufficient_data = FALSE;
+}
+
+
+/*
+ * Figure F.12: extend sign bit.
+ * On some machines, a shift and add will be faster than a table lookup.
+ */
+
+#ifdef AVOID_TABLES
+
+#define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x))
+
+#else
+
+#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x))
+
+static const int extend_test[16] = /* entry n is 2**(n-1) */
+ { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
+ 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
+
+static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
+ { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1,
+ ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1,
+ ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1,
+ ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 };
+
+#endif /* AVOID_TABLES */
+
+
+/*
+ * Check for a restart marker & resynchronize decoder.
+ * Returns FALSE if must suspend.
+ */
+
+METHODDEF(boolean)
+process_restart (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsd->entropy_private;
+ /* int ci; */
+
+ /* Throw away any unused bits remaining in bit buffer; */
+ /* include any full bytes in next_marker's count of discarded bytes */
+ cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8;
+ entropy->bitstate.bits_left = 0;
+
+ /* Advance past the RSTn marker */
+ if (! (*cinfo->marker->read_restart_marker) (cinfo))
+ return FALSE;
+
+ /* Reset out-of-data flag, unless read_restart_marker left us smack up
+ * against a marker. In that case we will end up treating the next data
+ * segment as empty, and we can avoid producing bogus output pixels by
+ * leaving the flag set.
+ */
+ if (cinfo->unread_marker == 0)
+ entropy->insufficient_data = FALSE;
+
+ return TRUE;
+}
+
+
+/*
+ * Decode and return nMCU's worth of Huffman-compressed differences.
+ * Each MCU is also disassembled and placed accordingly in diff_buf.
+ *
+ * MCU_col_num specifies the column of the first MCU being requested within
+ * the MCU-row. This tells us where to position the output row pointers in
+ * diff_buf.
+ *
+ * Returns the number of MCUs decoded. This may be less than nMCU if data
+ * source requested suspension. In that case no changes have been made to
+ * permanent state. (Exception: some output differences may already have
+ * been assigned. This is harmless for this module, since we'll just
+ * re-assign them on the next call.)
+ */
+
+METHODDEF(JDIMENSION)
+decode_mcus (j_decompress_ptr cinfo, JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num, JDIMENSION MCU_col_num, JDIMENSION nMCU)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy = (lhuff_entropy_ptr) losslsd->entropy_private;
+ unsigned int mcu_num;
+ int sampn, ci, yoffset, MCU_width, ptrn;
+ BITREAD_STATE_VARS;
+
+ /* Set output pointer locations based on MCU_col_num */
+ for (ptrn = 0; ptrn < entropy->num_output_ptrs; ptrn++) {
+ ci = entropy->output_ptr_info[ptrn].ci;
+ yoffset = entropy->output_ptr_info[ptrn].yoffset;
+ MCU_width = entropy->output_ptr_info[ptrn].MCU_width;
+ entropy->output_ptr[ptrn] =
+ diff_buf[ci][MCU_row_num + yoffset] + (MCU_col_num * MCU_width);
+ }
+
+ /*
+ * If we've run out of data, zero out the buffers and return.
+ * By resetting the undifferencer, the output samples will be CENTERJSAMPLE.
+ *
+ * NB: We should find a way to do this without interacting with the
+ * undifferencer module directly.
+ */
+ if (entropy->insufficient_data) {
+ for (ptrn = 0; ptrn < entropy->num_output_ptrs; ptrn++)
+ jzero_far((void FAR *) entropy->output_ptr[ptrn],
+ nMCU * entropy->output_ptr_info[ptrn].MCU_width * SIZEOF(JDIFF));
+
+ (*losslsd->predict_process_restart) (cinfo);
+ }
+
+ else {
+
+ /* Load up working state */
+ BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
+
+ /* Outer loop handles the number of MCU requested */
+
+ for (mcu_num = 0; mcu_num < nMCU; mcu_num++) {
+
+ /* Inner loop handles the samples in the MCU */
+ for (sampn = 0; sampn < cinfo->data_units_in_MCU; sampn++) {
+ d_derived_tbl * dctbl = entropy->cur_tbls[sampn];
+ register int s, r;
+
+ /* Section H.2.2: decode the sample difference */
+ HUFF_DECODE(s, br_state, dctbl, return mcu_num, label1);
+ if (s) {
+ if (s == 16) /* special case: always output 32768 */
+ s = 32768;
+ else { /* normal case: fetch subsequent bits */
+ CHECK_BIT_BUFFER(br_state, s, return mcu_num);
+ r = GET_BITS(s);
+ s = HUFF_EXTEND(r, s);
+ }
+ }
+
+ /* Output the sample difference */
+ *entropy->output_ptr[entropy->output_ptr_index[sampn]]++ = (JDIFF) s;
+ }
+
+ /* Completed MCU, so update state */
+ BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
+ }
+ }
+
+ return nMCU;
+}
+
+
+/*
+ * Module initialization routine for lossless Huffman entropy decoding.
+ */
+
+GLOBAL(void)
+jinit_lhuff_decoder (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ lhuff_entropy_ptr entropy;
+ int i;
+
+ entropy = (lhuff_entropy_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(lhuff_entropy_decoder));
+ losslsd->entropy_private = (void *) entropy;
+ losslsd->entropy_start_pass = start_pass_lhuff_decoder;
+ losslsd->entropy_process_restart = process_restart;
+ losslsd->entropy_decode_mcus = decode_mcus;
+
+ /* Mark tables unallocated */
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ entropy->derived_tbls[i] = NULL;
+ }
+}
+
+#endif /* D_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jdlossls.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the control logic for the lossless JPEG decompressor.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h"
+
+
+#ifdef D_LOSSLESS_SUPPORTED
+
+/*
+ * Compute output image dimensions and related values.
+ */
+
+METHODDEF(void)
+calc_output_dimensions (j_decompress_ptr cinfo)
+{
+ /* Hardwire it to "no scaling" */
+ cinfo->output_width = cinfo->image_width;
+ cinfo->output_height = cinfo->image_height;
+ /* jdinput.c has already initialized codec_data_unit to 1,
+ * and has computed unscaled downsampled_width and downsampled_height.
+ */
+}
+
+
+/*
+ * Initialize for an input processing pass.
+ */
+
+METHODDEF(void)
+start_input_pass (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+
+ (*losslsd->entropy_start_pass) (cinfo);
+ (*losslsd->predict_start_pass) (cinfo);
+ (*losslsd->scaler_start_pass) (cinfo);
+ (*losslsd->diff_start_input_pass) (cinfo);
+}
+
+
+/*
+ * Initialize the lossless decompression codec.
+ * This is called only once, during master selection.
+ */
+
+GLOBAL(void)
+jinit_lossless_d_codec(j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd;
+ boolean use_c_buffer;
+
+ /* Create subobject in permanent pool */
+ losslsd = (j_lossless_d_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(jpeg_lossless_d_codec));
+ cinfo->codec = (struct jpeg_d_codec *) losslsd;
+
+ /* Initialize sub-modules */
+ /* Entropy decoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+ jinit_arith_decoder(cinfo);
+ } else {
+ jinit_lhuff_decoder(cinfo);
+ }
+
+ /* Undifferencer */
+ jinit_undifferencer(cinfo);
+
+ /* Scaler */
+ jinit_d_scaler(cinfo);
+
+ use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
+ jinit_d_diff_controller(cinfo, use_c_buffer);
+
+ /* Initialize method pointers.
+ *
+ * Note: consume_data, start_output_pass and decompress_data are
+ * assigned in jddiffct.c.
+ */
+ losslsd->pub.calc_output_dimensions = calc_output_dimensions;
+ losslsd->pub.start_input_pass = start_input_pass;
+}
+
+#endif /* D_LOSSLESS_SUPPORTED */
--- /dev/null
+/*
+ * jdlossy.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the control logic for the lossy JPEG decompressor.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h"
+
+
+/*
+ * Compute output image dimensions and related values.
+ */
+
+METHODDEF(void)
+calc_output_dimensions (j_decompress_ptr cinfo)
+{
+#ifdef IDCT_SCALING_SUPPORTED
+ int ci;
+ jpeg_component_info *compptr;
+
+ /* Compute actual output image dimensions and DCT scaling choices. */
+ if (cinfo->scale_num * 8 <= cinfo->scale_denom) {
+ /* Provide 1/8 scaling */
+ cinfo->output_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width, 8L);
+ cinfo->output_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height, 8L);
+ cinfo->min_codec_data_unit = 1;
+ } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) {
+ /* Provide 1/4 scaling */
+ cinfo->output_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width, 4L);
+ cinfo->output_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height, 4L);
+ cinfo->min_codec_data_unit = 2;
+ } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) {
+ /* Provide 1/2 scaling */
+ cinfo->output_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width, 2L);
+ cinfo->output_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height, 2L);
+ cinfo->min_codec_data_unit = 4;
+ } else {
+ /* Provide 1/1 scaling */
+ cinfo->output_width = cinfo->image_width;
+ cinfo->output_height = cinfo->image_height;
+ cinfo->min_codec_data_unit = DCTSIZE;
+ }
+ /* In selecting the actual DCT scaling for each component, we try to
+ * scale up the chroma components via IDCT scaling rather than upsampling.
+ * This saves time if the upsampler gets to use 1:1 scaling.
+ * Note this code assumes that the supported DCT scalings are powers of 2.
+ */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ int ssize = cinfo->min_codec_data_unit;
+ while (ssize < DCTSIZE &&
+ (compptr->h_samp_factor * ssize * 2 <=
+ cinfo->max_h_samp_factor * cinfo->min_codec_data_unit) &&
+ (compptr->v_samp_factor * ssize * 2 <=
+ cinfo->max_v_samp_factor * cinfo->min_codec_data_unit)) {
+ ssize = ssize * 2;
+ }
+ compptr->codec_data_unit = ssize;
+ }
+
+ /* Recompute downsampled dimensions of components;
+ * application needs to know these if using raw downsampled data.
+ */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Size in samples, after IDCT scaling */
+ compptr->downsampled_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width *
+ (long) (compptr->h_samp_factor * compptr->codec_data_unit),
+ (long) (cinfo->max_h_samp_factor * DCTSIZE));
+ compptr->downsampled_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height *
+ (long) (compptr->v_samp_factor * compptr->codec_data_unit),
+ (long) (cinfo->max_v_samp_factor * DCTSIZE));
+ }
+
+#else /* !IDCT_SCALING_SUPPORTED */
+
+ /* Hardwire it to "no scaling" */
+ cinfo->output_width = cinfo->image_width;
+ cinfo->output_height = cinfo->image_height;
+ /* jdinput.c has already initialized codec_data_unit to DCTSIZE,
+ * and has computed unscaled downsampled_width and downsampled_height.
+ */
+
+#endif /* IDCT_SCALING_SUPPORTED */
+}
+
+
+/*
+ * Save away a copy of the Q-table referenced by each component present
+ * in the current scan, unless already saved during a prior scan.
+ *
+ * In a multiple-scan JPEG file, the encoder could assign different components
+ * the same Q-table slot number, but change table definitions between scans
+ * so that each component uses a different Q-table. (The IJG encoder is not
+ * currently capable of doing this, but other encoders might.) Since we want
+ * to be able to dequantize all the components at the end of the file, this
+ * means that we have to save away the table actually used for each component.
+ * We do this by copying the table at the start of the first scan containing
+ * the component.
+ * The JPEG spec prohibits the encoder from changing the contents of a Q-table
+ * slot between scans of a component using that slot. If the encoder does so
+ * anyway, this decoder will simply use the Q-table values that were current
+ * at the start of the first scan for the component.
+ *
+ * The decompressor output side looks only at the saved quant tables,
+ * not at the current Q-table slots.
+ */
+
+LOCAL(void)
+latch_quant_tables (j_decompress_ptr cinfo)
+{
+ int ci, qtblno;
+ jpeg_component_info *compptr;
+ JQUANT_TBL * qtbl;
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* No work if we already saved Q-table for this component */
+ if (compptr->quant_table != NULL)
+ continue;
+ /* Make sure specified quantization table is present */
+ qtblno = compptr->quant_tbl_no;
+ if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
+ cinfo->quant_tbl_ptrs[qtblno] == NULL)
+ ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
+ /* OK, save away the quantization table */
+ qtbl = (JQUANT_TBL *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(JQUANT_TBL));
+ MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
+ compptr->quant_table = qtbl;
+ }
+}
+
+
+/*
+ * Initialize for an input processing pass.
+ */
+
+METHODDEF(void)
+start_input_pass (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+
+ latch_quant_tables(cinfo);
+ (*lossyd->entropy_start_pass) (cinfo);
+ (*lossyd->coef_start_input_pass) (cinfo);
+}
+
+
+/*
+ * Initialize for an output processing pass.
+ */
+
+METHODDEF(void)
+start_output_pass (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+
+ (*lossyd->idct_start_pass) (cinfo);
+ (*lossyd->coef_start_output_pass) (cinfo);
+}
+
+/*
+ * Initialize the lossy decompression codec.
+ * This is called only once, during master selection.
+ */
+
+GLOBAL(void)
+jinit_lossy_d_codec (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd;
+ boolean use_c_buffer;
+
+ /* Create subobject in permanent pool */
+ lossyd = (j_lossy_d_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(jpeg_lossy_d_codec));
+ cinfo->codec = (struct jpeg_d_codec *) lossyd;
+
+ /* Initialize sub-modules */
+
+ /* Inverse DCT */
+ jinit_inverse_dct(cinfo);
+ /* Entropy decoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+ jinit_arith_decoder(cinfo);
+ } else {
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+#ifdef D_PROGRESSIVE_SUPPORTED
+ jinit_phuff_decoder(cinfo);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else
+ jinit_shuff_decoder(cinfo);
+ }
+
+ use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
+ jinit_d_coef_controller(cinfo, use_c_buffer);
+
+ /* Initialize method pointers.
+ *
+ * Note: consume_data and decompress_data are assigned in jdcoefct.c.
+ */
+ lossyd->pub.calc_output_dimensions = calc_output_dimensions;
+ lossyd->pub.start_input_pass = start_input_pass;
+ lossyd->pub.start_output_pass = start_output_pass;
+}
+
+
+
+
--- /dev/null
+/*
+ * jdmainct.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the main buffer controller for decompression.
+ * The main buffer lies between the JPEG decompressor proper and the
+ * post-processor; it holds downsampled data in the JPEG colorspace.
+ *
+ * Note that this code is bypassed in raw-data mode, since the application
+ * supplies the equivalent of the main buffer in that case.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * In the current system design, the main buffer need never be a full-image
+ * buffer; any full-height buffers will be found inside the coefficient or
+ * postprocessing controllers. Nonetheless, the main controller is not
+ * trivial. Its responsibility is to provide context rows for upsampling/
+ * rescaling, and doing this in an efficient fashion is a bit tricky.
+ *
+ * Postprocessor input data is counted in "row groups". A row group
+ * is defined to be (v_samp_factor * codec_data_unit / min_codec_data_unit)
+ * sample rows of each component. (We require codec_data_unit values to be
+ * chosen such that these numbers are integers. In practice codec_data_unit
+ * values will likely be powers of two, so we actually have the stronger
+ * condition that codec_data_unit / min_codec_data_unit is an integer.)
+ * Upsampling will typically produce max_v_samp_factor pixel rows from each
+ * row group (times any additional scale factor that the upsampler is
+ * applying).
+ *
+ * The decompression codec will deliver data to us one iMCU row at a time;
+ * each iMCU row contains v_samp_factor * codec_data_unit sample rows, or
+ * exactly min_codec_data_unit row groups. (This amount of data corresponds
+ * to one row of MCUs when the image is fully interleaved.) Note that the
+ * number of sample rows varies across components, but the number of row
+ * groups does not. Some garbage sample rows may be included in the last iMCU
+ * row at the bottom of the image.
+ *
+ * Depending on the vertical scaling algorithm used, the upsampler may need
+ * access to the sample row(s) above and below its current input row group.
+ * The upsampler is required to set need_context_rows TRUE at global selection
+ * time if so. When need_context_rows is FALSE, this controller can simply
+ * obtain one iMCU row at a time from the coefficient controller and dole it
+ * out as row groups to the postprocessor.
+ *
+ * When need_context_rows is TRUE, this controller guarantees that the buffer
+ * passed to postprocessing contains at least one row group's worth of samples
+ * above and below the row group(s) being processed. Note that the context
+ * rows "above" the first passed row group appear at negative row offsets in
+ * the passed buffer. At the top and bottom of the image, the required
+ * context rows are manufactured by duplicating the first or last real sample
+ * row; this avoids having special cases in the upsampling inner loops.
+ *
+ * The amount of context is fixed at one row group just because that's a
+ * convenient number for this controller to work with. The existing
+ * upsamplers really only need one sample row of context. An upsampler
+ * supporting arbitrary output rescaling might wish for more than one row
+ * group of context when shrinking the image; tough, we don't handle that.
+ * (This is justified by the assumption that downsizing will be handled mostly
+ * by adjusting the codec_data_unit values, so that the actual scale factor at
+ * the upsample step needn't be much less than one.)
+ *
+ * To provide the desired context, we have to retain the last two row groups
+ * of one iMCU row while reading in the next iMCU row. (The last row group
+ * can't be processed until we have another row group for its below-context,
+ * and so we have to save the next-to-last group too for its above-context.)
+ * We could do this most simply by copying data around in our buffer, but
+ * that'd be very slow. We can avoid copying any data by creating a rather
+ * strange pointer structure. Here's how it works. We allocate a workspace
+ * consisting of M+2 row groups (where M = min_codec_data_unit is the number
+ * of row groups per iMCU row). We create two sets of redundant pointers to
+ * the workspace. Labeling the physical row groups 0 to M+1, the synthesized
+ * pointer lists look like this:
+ * M+1 M-1
+ * master pointer --> 0 master pointer --> 0
+ * 1 1
+ * ... ...
+ * M-3 M-3
+ * M-2 M
+ * M-1 M+1
+ * M M-2
+ * M+1 M-1
+ * 0 0
+ * We read alternate iMCU rows using each master pointer; thus the last two
+ * row groups of the previous iMCU row remain un-overwritten in the workspace.
+ * The pointer lists are set up so that the required context rows appear to
+ * be adjacent to the proper places when we pass the pointer lists to the
+ * upsampler.
+ *
+ * The above pictures describe the normal state of the pointer lists.
+ * At top and bottom of the image, we diddle the pointer lists to duplicate
+ * the first or last sample row as necessary (this is cheaper than copying
+ * sample rows around).
+ *
+ * This scheme breaks down if M < 2, ie, min_codec_data_unit is 1. In that
+ * situation each iMCU row provides only one row group so the buffering logic
+ * must be different (eg, we must read two iMCU rows before we can emit the
+ * first row group). For now, we simply do not support providing context
+ * rows when min_codec_data_unit is 1. That combination seems unlikely to
+ * be worth providing --- if someone wants a 1/8th-size preview, they probably
+ * want it quick and dirty, so a context-free upsampler is sufficient.
+ */
+
+
+/* Private buffer controller object */
+
+typedef struct {
+ struct jpeg_d_main_controller pub; /* public fields */
+
+ /* Pointer to allocated workspace (M or M+2 row groups). */
+ JSAMPARRAY buffer[MAX_COMPONENTS];
+
+ boolean buffer_full; /* Have we gotten an iMCU row from decoder? */
+ JDIMENSION rowgroup_ctr; /* counts row groups output to postprocessor */
+
+ /* Remaining fields are only used in the context case. */
+
+ /* These are the master pointers to the funny-order pointer lists. */
+ JSAMPIMAGE xbuffer[2]; /* pointers to weird pointer lists */
+
+ int whichptr; /* indicates which pointer set is now in use */
+ int context_state; /* process_data state machine status */
+ JDIMENSION rowgroups_avail; /* row groups available to postprocessor */
+ JDIMENSION iMCU_row_ctr; /* counts iMCU rows to detect image top/bot */
+} my_main_controller;
+
+typedef my_main_controller * my_main_ptr;
+
+/* context_state values: */
+#define CTX_PREPARE_FOR_IMCU 0 /* need to prepare for MCU row */
+#define CTX_PROCESS_IMCU 1 /* feeding iMCU to postprocessor */
+#define CTX_POSTPONED_ROW 2 /* feeding postponed row group */
+
+
+/* Forward declarations */
+METHODDEF(void) process_data_simple_main
+ JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
+ JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail));
+METHODDEF(void) process_data_context_main
+ JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
+ JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail));
+#ifdef QUANT_2PASS_SUPPORTED
+METHODDEF(void) process_data_crank_post
+ JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
+ JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail));
+#endif
+
+
+LOCAL(void)
+alloc_funny_pointers (j_decompress_ptr cinfo)
+/* Allocate space for the funny pointer lists.
+ * This is done only once, not once per pass.
+ */
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+ int ci, rgroup;
+ int M = cinfo->min_codec_data_unit;
+ jpeg_component_info *compptr;
+ JSAMPARRAY xbuf;
+
+ /* Get top-level space for component array pointers.
+ * We alloc both arrays with one call to save a few cycles.
+ */
+ mainPtr->xbuffer[0] = (JSAMPIMAGE)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ cinfo->num_components * 2 * SIZEOF(JSAMPARRAY));
+ mainPtr->xbuffer[1] = mainPtr->xbuffer[0] + cinfo->num_components;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ rgroup = (compptr->v_samp_factor * compptr->codec_data_unit) /
+ cinfo->min_codec_data_unit; /* height of a row group of component */
+ /* Get space for pointer lists --- M+4 row groups in each list.
+ * We alloc both pointer lists with one call to save a few cycles.
+ */
+ xbuf = (JSAMPARRAY)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ 2 * (rgroup * (M + 4)) * SIZEOF(JSAMPROW));
+ xbuf += rgroup; /* want one row group at negative offsets */
+ mainPtr->xbuffer[0][ci] = xbuf;
+ xbuf += rgroup * (M + 4);
+ mainPtr->xbuffer[1][ci] = xbuf;
+ }
+}
+
+
+LOCAL(void)
+make_funny_pointers (j_decompress_ptr cinfo)
+/* Create the funny pointer lists discussed in the comments above.
+ * The actual workspace is already allocated (in mainPtr->buffer),
+ * and the space for the pointer lists is allocated too.
+ * This routine just fills in the curiously ordered lists.
+ * This will be repeated at the beginning of each pass.
+ */
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+ int ci, i, rgroup;
+ int M = cinfo->min_codec_data_unit;
+ jpeg_component_info *compptr;
+ JSAMPARRAY buf, xbuf0, xbuf1;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ rgroup = (compptr->v_samp_factor * compptr->codec_data_unit) /
+ cinfo->min_codec_data_unit; /* height of a row group of component */
+ xbuf0 = mainPtr->xbuffer[0][ci];
+ xbuf1 = mainPtr->xbuffer[1][ci];
+ /* First copy the workspace pointers as-is */
+ buf = mainPtr->buffer[ci];
+ for (i = 0; i < rgroup * (M + 2); i++) {
+ xbuf0[i] = xbuf1[i] = buf[i];
+ }
+ /* In the second list, put the last four row groups in swapped order */
+ for (i = 0; i < rgroup * 2; i++) {
+ xbuf1[rgroup*(M-2) + i] = buf[rgroup*M + i];
+ xbuf1[rgroup*M + i] = buf[rgroup*(M-2) + i];
+ }
+ /* The wraparound pointers at top and bottom will be filled later
+ * (see set_wraparound_pointers, below). Initially we want the "above"
+ * pointers to duplicate the first actual data line. This only needs
+ * to happen in xbuffer[0].
+ */
+ for (i = 0; i < rgroup; i++) {
+ xbuf0[i - rgroup] = xbuf0[0];
+ }
+ }
+}
+
+
+LOCAL(void)
+set_wraparound_pointers (j_decompress_ptr cinfo)
+/* Set up the "wraparound" pointers at top and bottom of the pointer lists.
+ * This changes the pointer list state from top-of-image to the normal state.
+ */
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+ int ci, i, rgroup;
+ int M = cinfo->min_codec_data_unit;
+ jpeg_component_info *compptr;
+ JSAMPARRAY xbuf0, xbuf1;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ rgroup = (compptr->v_samp_factor * compptr->codec_data_unit) /
+ cinfo->min_codec_data_unit; /* height of a row group of component */
+ xbuf0 = mainPtr->xbuffer[0][ci];
+ xbuf1 = mainPtr->xbuffer[1][ci];
+ for (i = 0; i < rgroup; i++) {
+ xbuf0[i - rgroup] = xbuf0[rgroup*(M+1) + i];
+ xbuf1[i - rgroup] = xbuf1[rgroup*(M+1) + i];
+ xbuf0[rgroup*(M+2) + i] = xbuf0[i];
+ xbuf1[rgroup*(M+2) + i] = xbuf1[i];
+ }
+ }
+}
+
+
+LOCAL(void)
+set_bottom_pointers (j_decompress_ptr cinfo)
+/* Change the pointer lists to duplicate the last sample row at the bottom
+ * of the image. whichptr indicates which xbuffer holds the final iMCU row.
+ * Also sets rowgroups_avail to indicate number of nondummy row groups in row.
+ */
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+ int ci, i, rgroup, iMCUheight, rows_left;
+ jpeg_component_info *compptr;
+ JSAMPARRAY xbuf;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Count sample rows in one iMCU row and in one row group */
+ iMCUheight = compptr->v_samp_factor * compptr->codec_data_unit;
+ rgroup = iMCUheight / cinfo->min_codec_data_unit;
+ /* Count nondummy sample rows remaining for this component */
+ rows_left = (int) (compptr->downsampled_height % (JDIMENSION) iMCUheight);
+ if (rows_left == 0) rows_left = iMCUheight;
+ /* Count nondummy row groups. Should get same answer for each component,
+ * so we need only do it once.
+ */
+ if (ci == 0) {
+ mainPtr->rowgroups_avail = (JDIMENSION) ((rows_left-1) / rgroup + 1);
+ }
+ /* Duplicate the last real sample row rgroup*2 times; this pads out the
+ * last partial rowgroup and ensures at least one full rowgroup of context.
+ */
+ xbuf = mainPtr->xbuffer[mainPtr->whichptr][ci];
+ for (i = 0; i < rgroup * 2; i++) {
+ xbuf[rows_left + i] = xbuf[rows_left-1];
+ }
+ }
+}
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_main (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+
+ switch (pass_mode) {
+ case JBUF_PASS_THRU:
+ if (cinfo->upsample->need_context_rows) {
+ mainPtr->pub.process_data = process_data_context_main;
+ make_funny_pointers(cinfo); /* Create the xbuffer[] lists */
+ mainPtr->whichptr = 0; /* Read first iMCU row into xbuffer[0] */
+ mainPtr->context_state = CTX_PREPARE_FOR_IMCU;
+ mainPtr->iMCU_row_ctr = 0;
+ } else {
+ /* Simple case with no context needed */
+ mainPtr->pub.process_data = process_data_simple_main;
+ }
+ mainPtr->buffer_full = FALSE; /* Mark buffer empty */
+ mainPtr->rowgroup_ctr = 0;
+ break;
+#ifdef QUANT_2PASS_SUPPORTED
+ case JBUF_CRANK_DEST:
+ /* For last pass of 2-pass quantization, just crank the postprocessor */
+ mainPtr->pub.process_data = process_data_crank_post;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ break;
+ }
+}
+
+
+/*
+ * Process some data.
+ * This handles the simple case where no context is required.
+ */
+
+METHODDEF(void)
+process_data_simple_main (j_decompress_ptr cinfo,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+ JDIMENSION rowgroups_avail;
+
+ /* Read input data if we haven't filled the main buffer yet */
+ if (! mainPtr->buffer_full) {
+ if (! (*cinfo->codec->decompress_data) (cinfo, mainPtr->buffer))
+ return; /* suspension forced, can do nothing more */
+ mainPtr->buffer_full = TRUE; /* OK, we have an iMCU row to work with */
+ }
+
+ /* There are always min_codec_data_unit row groups in an iMCU row. */
+ rowgroups_avail = (JDIMENSION) cinfo->min_codec_data_unit;
+ /* Note: at the bottom of the image, we may pass extra garbage row groups
+ * to the postprocessor. The postprocessor has to check for bottom
+ * of image anyway (at row resolution), so no point in us doing it too.
+ */
+
+ /* Feed the postprocessor */
+ (*cinfo->post->post_process_data) (cinfo, mainPtr->buffer,
+ &mainPtr->rowgroup_ctr, rowgroups_avail,
+ output_buf, out_row_ctr, out_rows_avail);
+
+ /* Has postprocessor consumed all the data yet? If so, mark buffer empty */
+ if (mainPtr->rowgroup_ctr >= rowgroups_avail) {
+ mainPtr->buffer_full = FALSE;
+ mainPtr->rowgroup_ctr = 0;
+ }
+}
+
+
+/*
+ * Process some data.
+ * This handles the case where context rows must be provided.
+ */
+
+METHODDEF(void)
+process_data_context_main (j_decompress_ptr cinfo,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ my_main_ptr mainPtr = (my_main_ptr) cinfo->main;
+
+ /* Read input data if we haven't filled the main buffer yet */
+ if (! mainPtr->buffer_full) {
+ if (! (*cinfo->codec->decompress_data) (cinfo,
+ mainPtr->xbuffer[mainPtr->whichptr]))
+ return; /* suspension forced, can do nothing more */
+ mainPtr->buffer_full = TRUE; /* OK, we have an iMCU row to work with */
+ mainPtr->iMCU_row_ctr++; /* count rows received */
+ }
+
+ /* Postprocessor typically will not swallow all the input data it is handed
+ * in one call (due to filling the output buffer first). Must be prepared
+ * to exit and restart. This switch lets us keep track of how far we got.
+ * Note that each case falls through to the next on successful completion.
+ */
+ switch (mainPtr->context_state) {
+ case CTX_POSTPONED_ROW:
+ /* Call postprocessor using previously set pointers for postponed row */
+ (*cinfo->post->post_process_data) (cinfo, mainPtr->xbuffer[mainPtr->whichptr],
+ &mainPtr->rowgroup_ctr, mainPtr->rowgroups_avail,
+ output_buf, out_row_ctr, out_rows_avail);
+ if (mainPtr->rowgroup_ctr < mainPtr->rowgroups_avail)
+ return; /* Need to suspend */
+ mainPtr->context_state = CTX_PREPARE_FOR_IMCU;
+ if (*out_row_ctr >= out_rows_avail)
+ return; /* Postprocessor exactly filled output buf */
+ /*FALLTHROUGH*/
+ case CTX_PREPARE_FOR_IMCU:
+ /* Prepare to process first M-1 row groups of this iMCU row */
+ mainPtr->rowgroup_ctr = 0;
+ mainPtr->rowgroups_avail = (JDIMENSION) (cinfo->min_codec_data_unit - 1);
+ /* Check for bottom of image: if so, tweak pointers to "duplicate"
+ * the last sample row, and adjust rowgroups_avail to ignore padding rows.
+ */
+ if (mainPtr->iMCU_row_ctr == cinfo->total_iMCU_rows)
+ set_bottom_pointers(cinfo);
+ mainPtr->context_state = CTX_PROCESS_IMCU;
+ /*FALLTHROUGH*/
+ case CTX_PROCESS_IMCU:
+ /* Call postprocessor using previously set pointers */
+ (*cinfo->post->post_process_data) (cinfo, mainPtr->xbuffer[mainPtr->whichptr],
+ &mainPtr->rowgroup_ctr, mainPtr->rowgroups_avail,
+ output_buf, out_row_ctr, out_rows_avail);
+ if (mainPtr->rowgroup_ctr < mainPtr->rowgroups_avail)
+ return; /* Need to suspend */
+ /* After the first iMCU, change wraparound pointers to normal state */
+ if (mainPtr->iMCU_row_ctr == 1)
+ set_wraparound_pointers(cinfo);
+ /* Prepare to load new iMCU row using other xbuffer list */
+ mainPtr->whichptr ^= 1; /* 0=>1 or 1=>0 */
+ mainPtr->buffer_full = FALSE;
+ /* Still need to process last row group of this iMCU row, */
+ /* which is saved at index M+1 of the other xbuffer */
+ mainPtr->rowgroup_ctr = (JDIMENSION) (cinfo->min_codec_data_unit + 1);
+ mainPtr->rowgroups_avail = (JDIMENSION) (cinfo->min_codec_data_unit + 2);
+ mainPtr->context_state = CTX_POSTPONED_ROW;
+ }
+}
+
+
+/*
+ * Process some data.
+ * Final pass of two-pass quantization: just call the postprocessor.
+ * Source data will be the postprocessor controller's internal buffer.
+ */
+
+#ifdef QUANT_2PASS_SUPPORTED
+
+METHODDEF(void)
+process_data_crank_post (j_decompress_ptr cinfo,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ (*cinfo->post->post_process_data) (cinfo, (JSAMPIMAGE) NULL,
+ (JDIMENSION *) NULL, (JDIMENSION) 0,
+ output_buf, out_row_ctr, out_rows_avail);
+}
+
+#endif /* QUANT_2PASS_SUPPORTED */
+
+
+/*
+ * Initialize main buffer controller.
+ */
+
+GLOBAL(void)
+jinit_d_main_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
+{
+ my_main_ptr mainPtr;
+ int ci, rgroup, ngroups;
+ jpeg_component_info *compptr;
+
+ mainPtr = (my_main_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_main_controller));
+ cinfo->main = (struct jpeg_d_main_controller *) mainPtr;
+ mainPtr->pub.start_pass = start_pass_main;
+
+ if (need_full_buffer) /* shouldn't happen */
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+
+ /* Allocate the workspace.
+ * ngroups is the number of row groups we need.
+ */
+ if (cinfo->upsample->need_context_rows) {
+ if (cinfo->min_codec_data_unit < 2) /* unsupported, see comments above */
+ ERREXIT(cinfo, JERR_NOTIMPL);
+ alloc_funny_pointers(cinfo); /* Alloc space for xbuffer[] lists */
+ ngroups = cinfo->min_codec_data_unit + 2;
+ } else {
+ ngroups = cinfo->min_codec_data_unit;
+ }
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ rgroup = (compptr->v_samp_factor * compptr->codec_data_unit) /
+ cinfo->min_codec_data_unit; /* height of a row group of component */
+ mainPtr->buffer[ci] = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ compptr->width_in_data_units * compptr->codec_data_unit,
+ (JDIMENSION) (rgroup * ngroups));
+ }
+}
--- /dev/null
+/*
+ * jdmarker.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains routines to decode JPEG datastream markers.
+ * Most of the complexity arises from our desire to support input
+ * suspension: if not all of the data for a marker is available,
+ * we must exit back to the application. On resumption, we reprocess
+ * the marker.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+typedef enum { /* JPEG marker codes */
+ M_SOF0 = 0xc0,
+ M_SOF1 = 0xc1,
+ M_SOF2 = 0xc2,
+ M_SOF3 = 0xc3,
+
+ M_SOF5 = 0xc5,
+ M_SOF6 = 0xc6,
+ M_SOF7 = 0xc7,
+
+ M_JPG = 0xc8,
+ M_SOF9 = 0xc9,
+ M_SOF10 = 0xca,
+ M_SOF11 = 0xcb,
+
+ M_SOF13 = 0xcd,
+ M_SOF14 = 0xce,
+ M_SOF15 = 0xcf,
+
+ M_DHT = 0xc4,
+
+ M_DAC = 0xcc,
+
+ M_RST0 = 0xd0,
+ M_RST1 = 0xd1,
+ M_RST2 = 0xd2,
+ M_RST3 = 0xd3,
+ M_RST4 = 0xd4,
+ M_RST5 = 0xd5,
+ M_RST6 = 0xd6,
+ M_RST7 = 0xd7,
+
+ M_SOI = 0xd8,
+ M_EOI = 0xd9,
+ M_SOS = 0xda,
+ M_DQT = 0xdb,
+ M_DNL = 0xdc,
+ M_DRI = 0xdd,
+ M_DHP = 0xde,
+ M_EXP = 0xdf,
+
+ M_APP0 = 0xe0,
+ M_APP1 = 0xe1,
+ M_APP2 = 0xe2,
+ M_APP3 = 0xe3,
+ M_APP4 = 0xe4,
+ M_APP5 = 0xe5,
+ M_APP6 = 0xe6,
+ M_APP7 = 0xe7,
+ M_APP8 = 0xe8,
+ M_APP9 = 0xe9,
+ M_APP10 = 0xea,
+ M_APP11 = 0xeb,
+ M_APP12 = 0xec,
+ M_APP13 = 0xed,
+ M_APP14 = 0xee,
+ M_APP15 = 0xef,
+
+ M_JPG0 = 0xf0,
+ M_JPG13 = 0xfd,
+ M_COM = 0xfe,
+
+ M_TEM = 0x01,
+
+ M_ERROR = 0x100
+} JPEG_MARKER;
+
+
+/* Private state */
+
+typedef struct {
+ struct jpeg_marker_reader pub; /* public fields */
+
+ /* Application-overridable marker processing methods */
+ jpeg_marker_parser_method process_COM;
+ jpeg_marker_parser_method process_APPn[16];
+
+ /* Limit on marker data length to save for each marker type */
+ unsigned int length_limit_COM;
+ unsigned int length_limit_APPn[16];
+
+ /* Status of COM/APPn marker saving */
+ jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
+ unsigned int bytes_read; /* data bytes read so far in marker */
+ /* Note: cur_marker is not linked into marker_list until it's all read. */
+} my_marker_reader;
+
+typedef my_marker_reader * my_marker_ptr;
+
+
+/*
+ * Macros for fetching data from the data source module.
+ *
+ * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
+ * the current restart point; we update them only when we have reached a
+ * suitable place to restart if a suspension occurs.
+ */
+
+/* Declare and initialize local copies of input pointer/count */
+#define INPUT_VARS(cinfo) \
+ struct jpeg_source_mgr * datasrc = (cinfo)->src; \
+ const JOCTET * next_input_byte = datasrc->next_input_byte; \
+ size_t bytes_in_buffer = datasrc->bytes_in_buffer
+
+/* Unload the local copies --- do this only at a restart boundary */
+#define INPUT_SYNC(cinfo) \
+ ( datasrc->next_input_byte = next_input_byte, \
+ datasrc->bytes_in_buffer = bytes_in_buffer )
+
+/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
+#define INPUT_RELOAD(cinfo) \
+ ( next_input_byte = datasrc->next_input_byte, \
+ bytes_in_buffer = datasrc->bytes_in_buffer )
+
+/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
+ * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
+ * but we must reload the local copies after a successful fill.
+ */
+#define MAKE_BYTE_AVAIL(cinfo,action) \
+ if (bytes_in_buffer == 0) { \
+ if (! (*datasrc->fill_input_buffer) (cinfo)) \
+ { action; } \
+ INPUT_RELOAD(cinfo); \
+ }
+
+/* Read a byte into variable V.
+ * If must suspend, take the specified action (typically "return FALSE").
+ */
+#define INPUT_BYTE(cinfo,V,action) \
+ MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
+ bytes_in_buffer--; \
+ V = GETJOCTET(*next_input_byte++); )
+
+/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
+ * V should be declared unsigned int or perhaps INT32.
+ */
+#define INPUT_2BYTES(cinfo,V,action) \
+ MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
+ bytes_in_buffer--; \
+ V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
+ MAKE_BYTE_AVAIL(cinfo,action); \
+ bytes_in_buffer--; \
+ V += GETJOCTET(*next_input_byte++); )
+
+
+/*
+ * Routines to process JPEG markers.
+ *
+ * Entry condition: JPEG marker itself has been read and its code saved
+ * in cinfo->unread_marker; input restart point is just after the marker.
+ *
+ * Exit: if return TRUE, have read and processed any parameters, and have
+ * updated the restart point to point after the parameters.
+ * If return FALSE, was forced to suspend before reaching end of
+ * marker parameters; restart point has not been moved. Same routine
+ * will be called again after application supplies more input data.
+ *
+ * This approach to suspension assumes that all of a marker's parameters
+ * can fit into a single input bufferload. This should hold for "normal"
+ * markers. Some COM/APPn markers might have large parameter segments
+ * that might not fit. If we are simply dropping such a marker, we use
+ * skip_input_data to get past it, and thereby put the problem on the
+ * source manager's shoulders. If we are saving the marker's contents
+ * into memory, we use a slightly different convention: when forced to
+ * suspend, the marker processor updates the restart point to the end of
+ * what it's consumed (ie, the end of the buffer) before returning FALSE.
+ * On resumption, cinfo->unread_marker still contains the marker code,
+ * but the data source will point to the next chunk of marker data.
+ * The marker processor must retain internal state to deal with this.
+ *
+ * Note that we don't bother to avoid duplicate trace messages if a
+ * suspension occurs within marker parameters. Other side effects
+ * require more care.
+ */
+
+
+LOCAL(boolean)
+get_soi (j_decompress_ptr cinfo)
+/* Process an SOI marker */
+{
+ int i;
+
+ TRACEMS(cinfo, 1, JTRC_SOI);
+
+ if (cinfo->marker->saw_SOI)
+ ERREXIT(cinfo, JERR_SOI_DUPLICATE);
+
+ /* Reset all parameters that are defined to be reset by SOI */
+
+ for (i = 0; i < NUM_ARITH_TBLS; i++) {
+ cinfo->arith_dc_L[i] = 0;
+ cinfo->arith_dc_U[i] = 1;
+ cinfo->arith_ac_K[i] = 5;
+ }
+ cinfo->restart_interval = 0;
+
+ /* Set initial assumptions for colorspace etc */
+
+ cinfo->jpeg_color_space = JCS_UNKNOWN;
+ cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
+
+ cinfo->saw_JFIF_marker = FALSE;
+ cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
+ cinfo->JFIF_minor_version = 1;
+ cinfo->density_unit = 0;
+ cinfo->X_density = 1;
+ cinfo->Y_density = 1;
+ cinfo->saw_Adobe_marker = FALSE;
+ cinfo->Adobe_transform = 0;
+
+ cinfo->marker->saw_SOI = TRUE;
+
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+get_sof (j_decompress_ptr cinfo, J_CODEC_PROCESS process, boolean is_arith,
+ int data_unit)
+/* Process a SOFn marker */
+{
+ INT32 length;
+ int c, ci;
+ jpeg_component_info * compptr;
+ INPUT_VARS(cinfo);
+
+ cinfo->data_unit = data_unit;
+ cinfo->process = process;
+ cinfo->arith_code = is_arith;
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
+ INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
+ INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
+ INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
+
+ length -= 8;
+
+ TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
+ (int) cinfo->image_width, (int) cinfo->image_height,
+ cinfo->num_components);
+
+ if (cinfo->marker->saw_SOF)
+ ERREXIT(cinfo, JERR_SOF_DUPLICATE);
+
+ /* We don't support files in which the image height is initially specified */
+ /* as 0 and is later redefined by DNL. As long as we have to check that, */
+ /* might as well have a general sanity check. */
+ if (cinfo->image_height <= 0 || cinfo->image_width <= 0
+ || cinfo->num_components <= 0)
+ ERREXIT(cinfo, JERR_EMPTY_IMAGE);
+
+ if (length != (cinfo->num_components * 3))
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ if (cinfo->comp_info == NULL) /* do only once, even if suspend */
+ cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ cinfo->num_components * SIZEOF(jpeg_component_info));
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ compptr->component_index = ci;
+ INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
+ INPUT_BYTE(cinfo, c, return FALSE);
+ compptr->h_samp_factor = (c >> 4) & 15;
+ compptr->v_samp_factor = (c ) & 15;
+ INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
+
+ TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
+ compptr->component_id, compptr->h_samp_factor,
+ compptr->v_samp_factor, compptr->quant_tbl_no);
+ }
+
+ cinfo->marker->saw_SOF = TRUE;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+get_sos (j_decompress_ptr cinfo)
+/* Process a SOS marker */
+{
+ INT32 length;
+ int i, ci, n, c, cc;
+ jpeg_component_info * compptr;
+ INPUT_VARS(cinfo);
+
+ if (! cinfo->marker->saw_SOF)
+ ERREXIT(cinfo, JERR_SOS_NO_SOF);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
+
+ TRACEMS1(cinfo, 1, JTRC_SOS, n);
+
+ if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ cinfo->comps_in_scan = n;
+
+ /* Collect the component-spec parameters */
+
+ for (i = 0; i < n; i++) {
+ INPUT_BYTE(cinfo, cc, return FALSE);
+ INPUT_BYTE(cinfo, c, return FALSE);
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (cc == compptr->component_id)
+ goto id_found;
+ }
+
+ ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
+
+ id_found:
+
+ cinfo->cur_comp_info[i] = compptr;
+ compptr->dc_tbl_no = (c >> 4) & 15;
+ compptr->ac_tbl_no = (c ) & 15;
+
+ TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
+ compptr->dc_tbl_no, compptr->ac_tbl_no);
+ }
+
+ /* Collect the additional scan parameters Ss, Se, Ah/Al. */
+ INPUT_BYTE(cinfo, c, return FALSE);
+ cinfo->Ss = c;
+ INPUT_BYTE(cinfo, c, return FALSE);
+ cinfo->Se = c;
+ INPUT_BYTE(cinfo, c, return FALSE);
+ cinfo->Ah = (c >> 4) & 15;
+ cinfo->Al = (c ) & 15;
+
+ TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
+ cinfo->Ah, cinfo->Al);
+
+ /* Prepare to scan data & restart markers */
+ cinfo->marker->next_restart_num = 0;
+
+ /* Count another SOS marker */
+ cinfo->input_scan_number++;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+#ifdef D_ARITH_CODING_SUPPORTED
+
+LOCAL(boolean)
+get_dac (j_decompress_ptr cinfo)
+/* Process a DAC marker */
+{
+ INT32 length;
+ int index, val;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ while (length > 0) {
+ INPUT_BYTE(cinfo, index, return FALSE);
+ INPUT_BYTE(cinfo, val, return FALSE);
+
+ length -= 2;
+
+ TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
+
+ if (index < 0 || index >= (2*NUM_ARITH_TBLS))
+ ERREXIT1(cinfo, JERR_DAC_INDEX, index);
+
+ if (index >= NUM_ARITH_TBLS) { /* define AC table */
+ cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
+ } else { /* define DC table */
+ cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
+ cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
+ if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
+ ERREXIT1(cinfo, JERR_DAC_VALUE, val);
+ }
+ }
+
+ if (length != 0)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+#else /* ! D_ARITH_CODING_SUPPORTED */
+
+#define get_dac(cinfo) skip_variable(cinfo)
+
+#endif /* D_ARITH_CODING_SUPPORTED */
+
+
+LOCAL(boolean)
+get_dht (j_decompress_ptr cinfo)
+/* Process a DHT marker */
+{
+ INT32 length;
+ UINT8 bits[17];
+ UINT8 huffval[256];
+ int i, index, count;
+ JHUFF_TBL **htblptr;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ while (length > 16) {
+ INPUT_BYTE(cinfo, index, return FALSE);
+
+ TRACEMS1(cinfo, 1, JTRC_DHT, index);
+
+ bits[0] = 0;
+ count = 0;
+ for (i = 1; i <= 16; i++) {
+ INPUT_BYTE(cinfo, bits[i], return FALSE);
+ count += bits[i];
+ }
+
+ length -= 1 + 16;
+
+ TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
+ bits[1], bits[2], bits[3], bits[4],
+ bits[5], bits[6], bits[7], bits[8]);
+ TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
+ bits[9], bits[10], bits[11], bits[12],
+ bits[13], bits[14], bits[15], bits[16]);
+
+ /* Here we just do minimal validation of the counts to avoid walking
+ * off the end of our table space. jdhuff.c will check more carefully.
+ */
+ if (count > 256 || ((INT32) count) > length)
+ ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
+
+ for (i = 0; i < count; i++)
+ INPUT_BYTE(cinfo, huffval[i], return FALSE);
+
+ length -= count;
+
+ if (index & 0x10) { /* AC table definition */
+ index -= 0x10;
+ htblptr = &cinfo->ac_huff_tbl_ptrs[index];
+ } else { /* DC table definition */
+ htblptr = &cinfo->dc_huff_tbl_ptrs[index];
+ }
+
+ if (index < 0 || index >= NUM_HUFF_TBLS)
+ ERREXIT1(cinfo, JERR_DHT_INDEX, index);
+
+ if (*htblptr == NULL)
+ *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+
+ MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
+ MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
+ }
+
+ if (length != 0)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+get_dqt (j_decompress_ptr cinfo)
+/* Process a DQT marker */
+{
+ INT32 length;
+ int n, i, prec;
+ unsigned int tmp;
+ JQUANT_TBL *quant_ptr;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ while (length > 0) {
+ INPUT_BYTE(cinfo, n, return FALSE);
+ prec = n >> 4;
+ n &= 0x0F;
+
+ TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
+
+ if (n >= NUM_QUANT_TBLS)
+ ERREXIT1(cinfo, JERR_DQT_INDEX, n);
+
+ if (cinfo->quant_tbl_ptrs[n] == NULL)
+ cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
+ quant_ptr = cinfo->quant_tbl_ptrs[n];
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ if (prec)
+ INPUT_2BYTES(cinfo, tmp, return FALSE);
+ else
+ INPUT_BYTE(cinfo, tmp, return FALSE);
+ /* We convert the zigzag-order table to natural array order. */
+ quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
+ }
+
+ if (cinfo->err->trace_level >= 2) {
+ for (i = 0; i < DCTSIZE2; i += 8) {
+ TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
+ quant_ptr->quantval[i], quant_ptr->quantval[i+1],
+ quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
+ quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
+ quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
+ }
+ }
+
+ length -= DCTSIZE2+1;
+ if (prec) length -= DCTSIZE2;
+ }
+
+ if (length != 0)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+get_dri (j_decompress_ptr cinfo)
+/* Process a DRI marker */
+{
+ INT32 length;
+ unsigned int tmp;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+
+ if (length != 4)
+ ERREXIT(cinfo, JERR_BAD_LENGTH);
+
+ INPUT_2BYTES(cinfo, tmp, return FALSE);
+
+ TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
+
+ cinfo->restart_interval = tmp;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+/*
+ * Routines for processing APPn and COM markers.
+ * These are either saved in memory or discarded, per application request.
+ * APP0 and APP14 are specially checked to see if they are
+ * JFIF and Adobe markers, respectively.
+ */
+
+#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
+#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
+#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
+
+
+LOCAL(void)
+examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
+ unsigned int datalen, INT32 remaining)
+/* Examine first few bytes from an APP0.
+ * Take appropriate action if it is a JFIF marker.
+ * datalen is # of bytes at data[], remaining is length of rest of marker data.
+ */
+{
+ INT32 totallen = (INT32) datalen + remaining;
+
+ if (datalen >= APP0_DATA_LEN &&
+ GETJOCTET(data[0]) == 0x4A &&
+ GETJOCTET(data[1]) == 0x46 &&
+ GETJOCTET(data[2]) == 0x49 &&
+ GETJOCTET(data[3]) == 0x46 &&
+ GETJOCTET(data[4]) == 0) {
+ /* Found JFIF APP0 marker: save info */
+ cinfo->saw_JFIF_marker = TRUE;
+ cinfo->JFIF_major_version = GETJOCTET(data[5]);
+ cinfo->JFIF_minor_version = GETJOCTET(data[6]);
+ cinfo->density_unit = GETJOCTET(data[7]);
+ cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
+ cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
+ /* Check version.
+ * Major version must be 1, anything else signals an incompatible change.
+ * (We used to treat this as an error, but now it's a nonfatal warning,
+ * because some bozo at Hijaak couldn't read the spec.)
+ * Minor version should be 0..2, but process anyway if newer.
+ */
+ if (cinfo->JFIF_major_version != 1)
+ WARNMS2(cinfo, JWRN_JFIF_MAJOR,
+ cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
+ /* Generate trace messages */
+ TRACEMS5(cinfo, 1, JTRC_JFIF,
+ cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
+ cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
+ /* Validate thumbnail dimensions and issue appropriate messages */
+ if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
+ TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
+ GETJOCTET(data[12]), GETJOCTET(data[13]));
+ totallen -= APP0_DATA_LEN;
+ if (totallen !=
+ ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
+ TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
+ } else if (datalen >= 6 &&
+ GETJOCTET(data[0]) == 0x4A &&
+ GETJOCTET(data[1]) == 0x46 &&
+ GETJOCTET(data[2]) == 0x58 &&
+ GETJOCTET(data[3]) == 0x58 &&
+ GETJOCTET(data[4]) == 0) {
+ /* Found JFIF "JFXX" extension APP0 marker */
+ /* The library doesn't actually do anything with these,
+ * but we try to produce a helpful trace message.
+ */
+ switch (GETJOCTET(data[5])) {
+ case 0x10:
+ TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
+ break;
+ case 0x11:
+ TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
+ break;
+ case 0x13:
+ TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
+ break;
+ default:
+ TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
+ GETJOCTET(data[5]), (int) totallen);
+ break;
+ }
+ } else {
+ /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
+ TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
+ }
+}
+
+
+LOCAL(void)
+examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
+ unsigned int datalen, INT32 remaining)
+/* Examine first few bytes from an APP14.
+ * Take appropriate action if it is an Adobe marker.
+ * datalen is # of bytes at data[], remaining is length of rest of marker data.
+ */
+{
+ unsigned int version, flags0, flags1, transform;
+
+ if (datalen >= APP14_DATA_LEN &&
+ GETJOCTET(data[0]) == 0x41 &&
+ GETJOCTET(data[1]) == 0x64 &&
+ GETJOCTET(data[2]) == 0x6F &&
+ GETJOCTET(data[3]) == 0x62 &&
+ GETJOCTET(data[4]) == 0x65) {
+ /* Found Adobe APP14 marker */
+ version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
+ flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
+ flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
+ transform = GETJOCTET(data[11]);
+ TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
+ cinfo->saw_Adobe_marker = TRUE;
+ cinfo->Adobe_transform = (UINT8) transform;
+ } else {
+ /* Start of APP14 does not match "Adobe", or too short */
+ TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
+ }
+}
+
+
+METHODDEF(boolean)
+get_interesting_appn (j_decompress_ptr cinfo)
+/* Process an APP0 or APP14 marker without saving it */
+{
+ INT32 length;
+ JOCTET b[APPN_DATA_LEN];
+ unsigned int i, numtoread;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ /* get the interesting part of the marker data */
+ if (length >= APPN_DATA_LEN)
+ numtoread = APPN_DATA_LEN;
+ else if (length > 0)
+ numtoread = (unsigned int) length;
+ else
+ numtoread = 0;
+ for (i = 0; i < numtoread; i++)
+ INPUT_BYTE(cinfo, b[i], return FALSE);
+ length -= numtoread;
+
+ /* process it */
+ switch (cinfo->unread_marker) {
+ case M_APP0:
+ examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
+ break;
+ case M_APP14:
+ examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
+ break;
+ default:
+ /* can't get here unless jpeg_save_markers chooses wrong processor */
+ ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
+ break;
+ }
+
+ /* skip any remaining data -- could be lots */
+ INPUT_SYNC(cinfo);
+ if (length > 0)
+ (*cinfo->src->skip_input_data) (cinfo, (long) length);
+
+ return TRUE;
+}
+
+
+#ifdef SAVE_MARKERS_SUPPORTED
+
+METHODDEF(boolean)
+save_marker (j_decompress_ptr cinfo)
+/* Save an APPn or COM marker into the marker list */
+{
+ my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
+ jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
+ unsigned int bytes_read, data_length;
+ JOCTET FAR * data;
+ INT32 length = 0;
+ INPUT_VARS(cinfo);
+
+ if (cur_marker == NULL) {
+ /* begin reading a marker */
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+ if (length >= 0) { /* watch out for bogus length word */
+ /* figure out how much we want to save */
+ unsigned int limit;
+ if (cinfo->unread_marker == (int) M_COM)
+ limit = marker->length_limit_COM;
+ else
+ limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
+ if ((unsigned int) length < limit)
+ limit = (unsigned int) length;
+ /* allocate and initialize the marker item */
+ cur_marker = (jpeg_saved_marker_ptr)
+ (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(struct jpeg_marker_struct) + limit);
+ cur_marker->next = NULL;
+ cur_marker->marker = (UINT8) cinfo->unread_marker;
+ cur_marker->original_length = (unsigned int) length;
+ cur_marker->data_length = limit;
+ /* data area is just beyond the jpeg_marker_struct */
+ data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
+ marker->cur_marker = cur_marker;
+ marker->bytes_read = 0;
+ bytes_read = 0;
+ data_length = limit;
+ } else {
+ /* deal with bogus length word */
+ bytes_read = data_length = 0;
+ data = NULL;
+ }
+ } else {
+ /* resume reading a marker */
+ bytes_read = marker->bytes_read;
+ data_length = cur_marker->data_length;
+ data = cur_marker->data + bytes_read;
+ }
+
+ while (bytes_read < data_length) {
+ INPUT_SYNC(cinfo); /* move the restart point to here */
+ marker->bytes_read = bytes_read;
+ /* If there's not at least one byte in buffer, suspend */
+ MAKE_BYTE_AVAIL(cinfo, return FALSE);
+ /* Copy bytes with reasonable rapidity */
+ while (bytes_read < data_length && bytes_in_buffer > 0) {
+ *data++ = *next_input_byte++;
+ bytes_in_buffer--;
+ bytes_read++;
+ }
+ }
+
+ /* Done reading what we want to read */
+ if (cur_marker != NULL) { /* will be NULL if bogus length word */
+ /* Add new marker to end of list */
+ if (cinfo->marker_list == NULL) {
+ cinfo->marker_list = cur_marker;
+ } else {
+ jpeg_saved_marker_ptr prev = cinfo->marker_list;
+ while (prev->next != NULL)
+ prev = prev->next;
+ prev->next = cur_marker;
+ }
+ /* Reset pointer & calc remaining data length */
+ data = cur_marker->data;
+ length = cur_marker->original_length - data_length;
+ }
+ /* Reset to initial state for next marker */
+ marker->cur_marker = NULL;
+
+ /* Process the marker if interesting; else just make a generic trace msg */
+ switch (cinfo->unread_marker) {
+ case M_APP0:
+ examine_app0(cinfo, data, data_length, length);
+ break;
+ case M_APP14:
+ examine_app14(cinfo, data, data_length, length);
+ break;
+ default:
+ TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
+ (int) (data_length + length));
+ break;
+ }
+
+ /* skip any remaining data -- could be lots */
+ INPUT_SYNC(cinfo); /* do before skip_input_data */
+ if (length > 0)
+ (*cinfo->src->skip_input_data) (cinfo, (long) length);
+
+ return TRUE;
+}
+
+#endif /* SAVE_MARKERS_SUPPORTED */
+
+
+METHODDEF(boolean)
+skip_variable (j_decompress_ptr cinfo)
+/* Skip over an unknown or uninteresting variable-length marker */
+{
+ INT32 length;
+ INPUT_VARS(cinfo);
+
+ INPUT_2BYTES(cinfo, length, return FALSE);
+ length -= 2;
+
+ TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
+
+ INPUT_SYNC(cinfo); /* do before skip_input_data */
+ if (length > 0)
+ (*cinfo->src->skip_input_data) (cinfo, (long) length);
+
+ return TRUE;
+}
+
+
+/*
+ * Find the next JPEG marker, save it in cinfo->unread_marker.
+ * Returns FALSE if had to suspend before reaching a marker;
+ * in that case cinfo->unread_marker is unchanged.
+ *
+ * Note that the result might not be a valid marker code,
+ * but it will never be 0 or FF.
+ */
+
+LOCAL(boolean)
+next_marker (j_decompress_ptr cinfo)
+{
+ int c;
+ INPUT_VARS(cinfo);
+
+ for (;;) {
+ INPUT_BYTE(cinfo, c, return FALSE);
+ /* Skip any non-FF bytes.
+ * This may look a bit inefficient, but it will not occur in a valid file.
+ * We sync after each discarded byte so that a suspending data source
+ * can discard the byte from its buffer.
+ */
+ while (c != 0xFF) {
+ cinfo->marker->discarded_bytes++;
+ INPUT_SYNC(cinfo);
+ INPUT_BYTE(cinfo, c, return FALSE);
+ }
+ /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
+ * pad bytes, so don't count them in discarded_bytes. We assume there
+ * will not be so many consecutive FF bytes as to overflow a suspending
+ * data source's input buffer.
+ */
+ do {
+ INPUT_BYTE(cinfo, c, return FALSE);
+ } while (c == 0xFF);
+ if (c != 0)
+ break; /* found a valid marker, exit loop */
+ /* Reach here if we found a stuffed-zero data sequence (FF/00).
+ * Discard it and loop back to try again.
+ */
+ cinfo->marker->discarded_bytes += 2;
+ INPUT_SYNC(cinfo);
+ }
+
+ if (cinfo->marker->discarded_bytes != 0) {
+ WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
+ cinfo->marker->discarded_bytes = 0;
+ }
+
+ cinfo->unread_marker = c;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+LOCAL(boolean)
+first_marker (j_decompress_ptr cinfo)
+/* Like next_marker, but used to obtain the initial SOI marker. */
+/* For this marker, we do not allow preceding garbage or fill; otherwise,
+ * we might well scan an entire input file before realizing it ain't JPEG.
+ * If an application wants to process non-JFIF files, it must seek to the
+ * SOI before calling the JPEG library.
+ */
+{
+ int c, c2;
+ INPUT_VARS(cinfo);
+
+ INPUT_BYTE(cinfo, c, return FALSE);
+ INPUT_BYTE(cinfo, c2, return FALSE);
+ if (c != 0xFF || c2 != (int) M_SOI)
+ ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
+
+ cinfo->unread_marker = c2;
+
+ INPUT_SYNC(cinfo);
+ return TRUE;
+}
+
+
+/*
+ * Read markers until SOS or EOI.
+ *
+ * Returns same codes as are defined for jpeg_consume_input:
+ * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
+ */
+
+METHODDEF(int)
+read_markers (j_decompress_ptr cinfo)
+{
+ /* Outer loop repeats once for each marker. */
+ for (;;) {
+ /* Collect the marker proper, unless we already did. */
+ /* NB: first_marker() enforces the requirement that SOI appear first. */
+ if (cinfo->unread_marker == 0) {
+ if (! cinfo->marker->saw_SOI) {
+ if (! first_marker(cinfo))
+ return JPEG_SUSPENDED;
+ } else {
+ if (! next_marker(cinfo))
+ return JPEG_SUSPENDED;
+ }
+ }
+ /* At this point cinfo->unread_marker contains the marker code and the
+ * input point is just past the marker proper, but before any parameters.
+ * A suspension will cause us to return with this state still true.
+ */
+ switch (cinfo->unread_marker) {
+ case M_SOI:
+ if (! get_soi(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF0: /* Baseline */
+ case M_SOF1: /* Extended sequential, Huffman */
+ if (! get_sof(cinfo, JPROC_SEQUENTIAL, FALSE, DCTSIZE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF2: /* Progressive, Huffman */
+ if (! get_sof(cinfo, JPROC_PROGRESSIVE, FALSE, DCTSIZE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF3: /* Lossless, Huffman */
+ if (! get_sof(cinfo, JPROC_LOSSLESS, FALSE, 1))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF9: /* Extended sequential, arithmetic */
+ if (! get_sof(cinfo, JPROC_SEQUENTIAL, TRUE, DCTSIZE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF10: /* Progressive, arithmetic */
+ if (! get_sof(cinfo, JPROC_PROGRESSIVE, TRUE, DCTSIZE))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_SOF11: /* Lossless, arithmetic */
+ if (! get_sof(cinfo, JPROC_LOSSLESS, TRUE, 1))
+ return JPEG_SUSPENDED;
+ break;
+
+ /* Currently unsupported SOFn types */
+ case M_SOF5: /* Differential sequential, Huffman */
+ case M_SOF6: /* Differential progressive, Huffman */
+ case M_SOF7: /* Differential lossless, Huffman */
+ case M_JPG: /* Reserved for JPEG extensions */
+ case M_SOF13: /* Differential sequential, arithmetic */
+ case M_SOF14: /* Differential progressive, arithmetic */
+ case M_SOF15: /* Differential lossless, arithmetic */
+ ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
+ break;
+
+ case M_SOS:
+ if (! get_sos(cinfo))
+ return JPEG_SUSPENDED;
+ cinfo->unread_marker = 0; /* processed the marker */
+ return JPEG_REACHED_SOS;
+
+ case M_EOI:
+ TRACEMS(cinfo, 1, JTRC_EOI);
+ cinfo->unread_marker = 0; /* processed the marker */
+ return JPEG_REACHED_EOI;
+
+ case M_DAC:
+ if (! get_dac(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_DHT:
+ if (! get_dht(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_DQT:
+ if (! get_dqt(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_DRI:
+ if (! get_dri(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_APP0:
+ case M_APP1:
+ case M_APP2:
+ case M_APP3:
+ case M_APP4:
+ case M_APP5:
+ case M_APP6:
+ case M_APP7:
+ case M_APP8:
+ case M_APP9:
+ case M_APP10:
+ case M_APP11:
+ case M_APP12:
+ case M_APP13:
+ case M_APP14:
+ case M_APP15:
+ if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
+ cinfo->unread_marker - (int) M_APP0]) (cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_COM:
+ if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ case M_RST0: /* these are all parameterless */
+ case M_RST1:
+ case M_RST2:
+ case M_RST3:
+ case M_RST4:
+ case M_RST5:
+ case M_RST6:
+ case M_RST7:
+ case M_TEM:
+ TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
+ break;
+
+ case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
+ if (! skip_variable(cinfo))
+ return JPEG_SUSPENDED;
+ break;
+
+ default: /* must be DHP, EXP, JPGn, or RESn */
+ /* For now, we treat the reserved markers as fatal errors since they are
+ * likely to be used to signal incompatible JPEG Part 3 extensions.
+ * Once the JPEG 3 version-number marker is well defined, this code
+ * ought to change!
+ */
+ ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
+ break;
+ }
+ /* Successfully processed marker, so reset state variable */
+ cinfo->unread_marker = 0;
+ } /* end loop */
+}
+
+
+/*
+ * Read a restart marker, which is expected to appear next in the datastream;
+ * if the marker is not there, take appropriate recovery action.
+ * Returns FALSE if suspension is required.
+ *
+ * This is called by the entropy decoder after it has read an appropriate
+ * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
+ * has already read a marker from the data source. Under normal conditions
+ * cinfo->unread_marker will be reset to 0 before returning; if not reset,
+ * it holds a marker which the decoder will be unable to read past.
+ */
+
+METHODDEF(boolean)
+read_restart_marker (j_decompress_ptr cinfo)
+{
+ /* Obtain a marker unless we already did. */
+ /* Note that next_marker will complain if it skips any data. */
+ if (cinfo->unread_marker == 0) {
+ if (! next_marker(cinfo))
+ return FALSE;
+ }
+
+ if (cinfo->unread_marker ==
+ ((int) M_RST0 + cinfo->marker->next_restart_num)) {
+ /* Normal case --- swallow the marker and let entropy decoder continue */
+ TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
+ cinfo->unread_marker = 0;
+ } else {
+ /* Uh-oh, the restart markers have been messed up. */
+ /* Let the data source manager determine how to resync. */
+ if (! (*cinfo->src->resync_to_restart) (cinfo,
+ cinfo->marker->next_restart_num))
+ return FALSE;
+ }
+
+ /* Update next-restart state */
+ cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
+
+ return TRUE;
+}
+
+
+/*
+ * This is the default resync_to_restart method for data source managers
+ * to use if they don't have any better approach. Some data source managers
+ * may be able to back up, or may have additional knowledge about the data
+ * which permits a more intelligent recovery strategy; such managers would
+ * presumably supply their own resync method.
+ *
+ * read_restart_marker calls resync_to_restart if it finds a marker other than
+ * the restart marker it was expecting. (This code is *not* used unless
+ * a nonzero restart interval has been declared.) cinfo->unread_marker is
+ * the marker code actually found (might be anything, except 0 or FF).
+ * The desired restart marker number (0..7) is passed as a parameter.
+ * This routine is supposed to apply whatever error recovery strategy seems
+ * appropriate in order to position the input stream to the next data segment.
+ * Note that cinfo->unread_marker is treated as a marker appearing before
+ * the current data-source input point; usually it should be reset to zero
+ * before returning.
+ * Returns FALSE if suspension is required.
+ *
+ * This implementation is substantially constrained by wanting to treat the
+ * input as a data stream; this means we can't back up. Therefore, we have
+ * only the following actions to work with:
+ * 1. Simply discard the marker and let the entropy decoder resume at next
+ * byte of file.
+ * 2. Read forward until we find another marker, discarding intervening
+ * data. (In theory we could look ahead within the current bufferload,
+ * without having to discard data if we don't find the desired marker.
+ * This idea is not implemented here, in part because it makes behavior
+ * dependent on buffer size and chance buffer-boundary positions.)
+ * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
+ * This will cause the entropy decoder to process an empty data segment,
+ * inserting dummy zeroes, and then we will reprocess the marker.
+ *
+ * #2 is appropriate if we think the desired marker lies ahead, while #3 is
+ * appropriate if the found marker is a future restart marker (indicating
+ * that we have missed the desired restart marker, probably because it got
+ * corrupted).
+ * We apply #2 or #3 if the found marker is a restart marker no more than
+ * two counts behind or ahead of the expected one. We also apply #2 if the
+ * found marker is not a legal JPEG marker code (it's certainly bogus data).
+ * If the found marker is a restart marker more than 2 counts away, we do #1
+ * (too much risk that the marker is erroneous; with luck we will be able to
+ * resync at some future point).
+ * For any valid non-restart JPEG marker, we apply #3. This keeps us from
+ * overrunning the end of a scan. An implementation limited to single-scan
+ * files might find it better to apply #2 for markers other than EOI, since
+ * any other marker would have to be bogus data in that case.
+ */
+
+GLOBAL(boolean)
+jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
+{
+ int marker = cinfo->unread_marker;
+ int action = 1;
+
+ /* Always put up a warning. */
+ WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
+
+ /* Outer loop handles repeated decision after scanning forward. */
+ for (;;) {
+ if (marker < (int) M_SOF0)
+ action = 2; /* invalid marker */
+ else if (marker < (int) M_RST0 || marker > (int) M_RST7)
+ action = 3; /* valid non-restart marker */
+ else {
+ if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
+ marker == ((int) M_RST0 + ((desired+2) & 7)))
+ action = 3; /* one of the next two expected restarts */
+ else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
+ marker == ((int) M_RST0 + ((desired-2) & 7)))
+ action = 2; /* a prior restart, so advance */
+ else
+ action = 1; /* desired restart or too far away */
+ }
+ TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
+ switch (action) {
+ case 1:
+ /* Discard marker and let entropy decoder resume processing. */
+ cinfo->unread_marker = 0;
+ return TRUE;
+ case 2:
+ /* Scan to the next marker, and repeat the decision loop. */
+ if (! next_marker(cinfo))
+ return FALSE;
+ marker = cinfo->unread_marker;
+ break;
+ case 3:
+ /* Return without advancing past this marker. */
+ /* Entropy decoder will be forced to process an empty segment. */
+ return TRUE;
+ }
+ } /* end loop */
+}
+
+
+/*
+ * Reset marker processing state to begin a fresh datastream.
+ */
+
+METHODDEF(void)
+reset_marker_reader (j_decompress_ptr cinfo)
+{
+ my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
+
+ cinfo->comp_info = NULL; /* until allocated by get_sof */
+ cinfo->input_scan_number = 0; /* no SOS seen yet */
+ cinfo->unread_marker = 0; /* no pending marker */
+ marker->pub.saw_SOI = FALSE; /* set internal state too */
+ marker->pub.saw_SOF = FALSE;
+ marker->pub.discarded_bytes = 0;
+ marker->cur_marker = NULL;
+}
+
+
+/*
+ * Initialize the marker reader module.
+ * This is called only once, when the decompression object is created.
+ */
+
+GLOBAL(void)
+jinit_marker_reader (j_decompress_ptr cinfo)
+{
+ my_marker_ptr marker;
+ int i;
+
+ /* Create subobject in permanent pool */
+ marker = (my_marker_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(my_marker_reader));
+ cinfo->marker = (struct jpeg_marker_reader *) marker;
+ /* Initialize public method pointers */
+ marker->pub.reset_marker_reader = reset_marker_reader;
+ marker->pub.read_markers = read_markers;
+ marker->pub.read_restart_marker = read_restart_marker;
+ /* Initialize COM/APPn processing.
+ * By default, we examine and then discard APP0 and APP14,
+ * but simply discard COM and all other APPn.
+ */
+ marker->process_COM = skip_variable;
+ marker->length_limit_COM = 0;
+ for (i = 0; i < 16; i++) {
+ marker->process_APPn[i] = skip_variable;
+ marker->length_limit_APPn[i] = 0;
+ }
+ marker->process_APPn[0] = get_interesting_appn;
+ marker->process_APPn[14] = get_interesting_appn;
+ /* Reset marker processing state */
+ reset_marker_reader(cinfo);
+}
+
+
+/*
+ * Control saving of COM and APPn markers into marker_list.
+ */
+
+#ifdef SAVE_MARKERS_SUPPORTED
+
+GLOBAL(void)
+jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
+ unsigned int length_limit)
+{
+ my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
+ long maxlength;
+ jpeg_marker_parser_method processor;
+
+ /* Length limit mustn't be larger than what we can allocate
+ * (should only be a concern in a 16-bit environment).
+ */
+ maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
+ if (((long) length_limit) > maxlength)
+ length_limit = (unsigned int) maxlength;
+
+ /* Choose processor routine to use.
+ * APP0/APP14 have special requirements.
+ */
+ if (length_limit) {
+ processor = save_marker;
+ /* If saving APP0/APP14, save at least enough for our internal use. */
+ if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
+ length_limit = APP0_DATA_LEN;
+ else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
+ length_limit = APP14_DATA_LEN;
+ } else {
+ processor = skip_variable;
+ /* If discarding APP0/APP14, use our regular on-the-fly processor. */
+ if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
+ processor = get_interesting_appn;
+ }
+
+ if (marker_code == (int) M_COM) {
+ marker->process_COM = processor;
+ marker->length_limit_COM = length_limit;
+ } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
+ marker->process_APPn[marker_code - (int) M_APP0] = processor;
+ marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
+ } else
+ ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
+}
+
+#endif /* SAVE_MARKERS_SUPPORTED */
+
+
+/*
+ * Install a special processing method for COM or APPn markers.
+ */
+
+GLOBAL(void)
+jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
+ jpeg_marker_parser_method routine)
+{
+ my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
+
+ if (marker_code == (int) M_COM)
+ marker->process_COM = routine;
+ else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
+ marker->process_APPn[marker_code - (int) M_APP0] = routine;
+ else
+ ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
+}
--- /dev/null
+/*
+ * jdmaster.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains master control logic for the JPEG decompressor.
+ * These routines are concerned with selecting the modules to be executed
+ * and with determining the number of passes and the work to be done in each
+ * pass.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private state */
+
+typedef struct {
+ struct jpeg_decomp_master pub; /* public fields */
+
+ int pass_number; /* # of passes completed */
+
+ boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
+
+ /* Saved references to initialized quantizer modules,
+ * in case we need to switch modes.
+ */
+ struct jpeg_color_quantizer * quantizer_1pass;
+ struct jpeg_color_quantizer * quantizer_2pass;
+} my_decomp_master;
+
+typedef my_decomp_master * my_master_ptr;
+
+
+/*
+ * Determine whether merged upsample/color conversion should be used.
+ * CRUCIAL: this must match the actual capabilities of jdmerge.c!
+ */
+
+LOCAL(boolean)
+use_merged_upsample (j_decompress_ptr cinfo)
+{
+#ifdef UPSAMPLE_MERGING_SUPPORTED
+ /* Merging is the equivalent of plain box-filter upsampling */
+ if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
+ return FALSE;
+ /* jdmerge.c only supports YCC=>RGB color conversion */
+ if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
+ cinfo->out_color_space != JCS_RGB ||
+ cinfo->out_color_components != RGB_PIXELSIZE)
+ return FALSE;
+ /* and it only handles 2h1v or 2h2v sampling ratios */
+ if (cinfo->comp_info[0].h_samp_factor != 2 ||
+ cinfo->comp_info[1].h_samp_factor != 1 ||
+ cinfo->comp_info[2].h_samp_factor != 1 ||
+ cinfo->comp_info[0].v_samp_factor > 2 ||
+ cinfo->comp_info[1].v_samp_factor != 1 ||
+ cinfo->comp_info[2].v_samp_factor != 1)
+ return FALSE;
+ /* furthermore, it doesn't work if each component has been
+ processed differently */
+ if (cinfo->comp_info[0].codec_data_unit != cinfo->min_codec_data_unit ||
+ cinfo->comp_info[1].codec_data_unit != cinfo->min_codec_data_unit ||
+ cinfo->comp_info[2].codec_data_unit != cinfo->min_codec_data_unit)
+ return FALSE;
+ /* ??? also need to test for upsample-time rescaling, when & if supported */
+ return TRUE; /* by golly, it'll work... */
+#else
+ return FALSE;
+#endif
+}
+
+
+/*
+ * Compute output image dimensions and related values.
+ * NOTE: this is exported for possible use by application.
+ * Hence it mustn't do anything that can't be done twice.
+ * Also note that it may be called before the master module is initialized!
+ */
+
+GLOBAL(void)
+jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
+/* Do computations that are needed before master selection phase */
+{
+ /* Prevent application from calling me at wrong times */
+ if (cinfo->global_state != DSTATE_READY)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ (*cinfo->codec->calc_output_dimensions) (cinfo);
+
+ /* Report number of components in selected colorspace. */
+ /* Probably this should be in the color conversion module... */
+ switch (cinfo->out_color_space) {
+ case JCS_GRAYSCALE:
+ cinfo->out_color_components = 1;
+ break;
+ case JCS_RGB:
+#if RGB_PIXELSIZE != 3
+ cinfo->out_color_components = RGB_PIXELSIZE;
+ break;
+#endif /* else share code with YCbCr */
+ case JCS_YCbCr:
+ cinfo->out_color_components = 3;
+ break;
+ case JCS_CMYK:
+ case JCS_YCCK:
+ cinfo->out_color_components = 4;
+ break;
+ default: /* else must be same colorspace as in file */
+ cinfo->out_color_components = cinfo->num_components;
+ break;
+ }
+ cinfo->output_components = (cinfo->quantize_colors ? 1 :
+ cinfo->out_color_components);
+
+ /* See if upsampler will want to emit more than one row at a time */
+ if (use_merged_upsample(cinfo))
+ cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
+ else
+ cinfo->rec_outbuf_height = 1;
+}
+
+
+/*
+ * Several decompression processes need to range-limit values to the range
+ * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
+ * due to noise introduced by quantization, roundoff error, etc. These
+ * processes are inner loops and need to be as fast as possible. On most
+ * machines, particularly CPUs with pipelines or instruction prefetch,
+ * a (subscript-check-less) C table lookup
+ * x = sample_range_limit[x];
+ * is faster than explicit tests
+ * if (x < 0) x = 0;
+ * else if (x > MAXJSAMPLE) x = MAXJSAMPLE;
+ * These processes all use a common table prepared by the routine below.
+ *
+ * For most steps we can mathematically guarantee that the initial value
+ * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
+ * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
+ * limiting step (just after the IDCT), a wildly out-of-range value is
+ * possible if the input data is corrupt. To avoid any chance of indexing
+ * off the end of memory and getting a bad-pointer trap, we perform the
+ * post-IDCT limiting thus:
+ * x = range_limit[x & MASK];
+ * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
+ * samples. Under normal circumstances this is more than enough range and
+ * a correct output will be generated; with bogus input data the mask will
+ * cause wraparound, and we will safely generate a bogus-but-in-range output.
+ * For the post-IDCT step, we want to convert the data from signed to unsigned
+ * representation by adding CENTERJSAMPLE at the same time that we limit it.
+ * So the post-IDCT limiting table ends up looking like this:
+ * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
+ * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
+ * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
+ * 0,1,...,CENTERJSAMPLE-1
+ * Negative inputs select values from the upper half of the table after
+ * masking.
+ *
+ * We can save some space by overlapping the start of the post-IDCT table
+ * with the simpler range limiting table. The post-IDCT table begins at
+ * sample_range_limit + CENTERJSAMPLE.
+ *
+ * Note that the table is allocated in near data space on PCs; it's small
+ * enough and used often enough to justify this.
+ */
+
+LOCAL(void)
+prepare_range_limit_table (j_decompress_ptr cinfo)
+/* Allocate and fill in the sample_range_limit table */
+{
+ JSAMPLE * table;
+ int i;
+
+ table = (JSAMPLE *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
+ table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
+ cinfo->sample_range_limit = table;
+ /* First segment of "simple" table: limit[x] = 0 for x < 0 */
+ MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
+ /* Main part of "simple" table: limit[x] = x */
+ for (i = 0; i <= MAXJSAMPLE; i++)
+ table[i] = (JSAMPLE) i;
+ table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
+ /* End of simple table, rest of first half of post-IDCT table */
+ for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
+ table[i] = MAXJSAMPLE;
+ /* Second half of post-IDCT table */
+ MEMZERO(table + (2 * (MAXJSAMPLE+1)),
+ (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
+ MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
+ cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
+}
+
+
+/*
+ * Master selection of decompression modules.
+ * This is done once at jpeg_start_decompress time. We determine
+ * which modules will be used and give them appropriate initialization calls.
+ * We also initialize the decompressor input side to begin consuming data.
+ *
+ * Since jpeg_read_header has finished, we know what is in the SOF
+ * and (first) SOS markers. We also have all the application parameter
+ * settings.
+ */
+
+LOCAL(void)
+master_selection (j_decompress_ptr cinfo)
+{
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+ long samplesperrow;
+ JDIMENSION jd_samplesperrow;
+
+ /* Initialize dimensions and other stuff */
+ jpeg_calc_output_dimensions(cinfo);
+ prepare_range_limit_table(cinfo);
+
+ /* Width of an output scanline must be representable as JDIMENSION. */
+ samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
+ jd_samplesperrow = (JDIMENSION) samplesperrow;
+ if ((long) jd_samplesperrow != samplesperrow)
+ ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
+
+ /* Initialize my private state */
+ master->pass_number = 0;
+ master->using_merged_upsample = use_merged_upsample(cinfo);
+
+ /* Color quantizer selection */
+ master->quantizer_1pass = NULL;
+ master->quantizer_2pass = NULL;
+ /* No mode changes if not using buffered-image mode. */
+ if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
+ cinfo->enable_1pass_quant = FALSE;
+ cinfo->enable_external_quant = FALSE;
+ cinfo->enable_2pass_quant = FALSE;
+ }
+ if (cinfo->quantize_colors) {
+ if (cinfo->raw_data_out)
+ ERREXIT(cinfo, JERR_NOTIMPL);
+ /* 2-pass quantizer only works in 3-component color space. */
+ if (cinfo->out_color_components != 3) {
+ cinfo->enable_1pass_quant = TRUE;
+ cinfo->enable_external_quant = FALSE;
+ cinfo->enable_2pass_quant = FALSE;
+ cinfo->colormap = NULL;
+ } else if (cinfo->colormap != NULL) {
+ cinfo->enable_external_quant = TRUE;
+ } else if (cinfo->two_pass_quantize) {
+ cinfo->enable_2pass_quant = TRUE;
+ } else {
+ cinfo->enable_1pass_quant = TRUE;
+ }
+
+ if (cinfo->enable_1pass_quant) {
+#ifdef QUANT_1PASS_SUPPORTED
+ jinit_1pass_quantizer(cinfo);
+ master->quantizer_1pass = cinfo->cquantize;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ }
+
+ /* We use the 2-pass code to map to external colormaps. */
+ if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
+#ifdef QUANT_2PASS_SUPPORTED
+ jinit_2pass_quantizer(cinfo);
+ master->quantizer_2pass = cinfo->cquantize;
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ }
+ /* If both quantizers are initialized, the 2-pass one is left active;
+ * this is necessary for starting with quantization to an external map.
+ */
+ }
+
+ /* Post-processing: in particular, color conversion first */
+ if (! cinfo->raw_data_out) {
+ if (master->using_merged_upsample) {
+#ifdef UPSAMPLE_MERGING_SUPPORTED
+ jinit_merged_upsampler(cinfo); /* does color conversion too */
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif
+ } else {
+ jinit_color_deconverter(cinfo);
+ jinit_upsampler(cinfo);
+ }
+ jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
+ }
+
+ /* Initialize principal buffer controllers. */
+ if (! cinfo->raw_data_out)
+ jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
+
+ /* We can now tell the memory manager to allocate virtual arrays. */
+ (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
+
+ /* Initialize input side of decompressor to consume first scan. */
+ (*cinfo->inputctl->start_input_pass) (cinfo);
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+ /* If jpeg_start_decompress will read the whole file, initialize
+ * progress monitoring appropriately. The input step is counted
+ * as one pass.
+ */
+ if (cinfo->progress != NULL && ! cinfo->buffered_image &&
+ cinfo->inputctl->has_multiple_scans) {
+ int nscans;
+ /* Estimate number of scans to set pass_limit. */
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+ /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
+ nscans = 2 + 3 * cinfo->num_components;
+ } else {
+ /* For a nonprogressive multiscan file, estimate 1 scan per component. */
+ nscans = cinfo->num_components;
+ }
+ cinfo->progress->pass_counter = 0L;
+ cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
+ cinfo->progress->completed_passes = 0;
+ cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
+ /* Count the input pass as done */
+ master->pass_number++;
+ }
+#endif /* D_MULTISCAN_FILES_SUPPORTED */
+}
+
+
+/*
+ * Per-pass setup.
+ * This is called at the beginning of each output pass. We determine which
+ * modules will be active during this pass and give them appropriate
+ * start_pass calls. We also set is_dummy_pass to indicate whether this
+ * is a "real" output pass or a dummy pass for color quantization.
+ * (In the latter case, jdapistd.c will crank the pass to completion.)
+ */
+
+METHODDEF(void)
+prepare_for_output_pass (j_decompress_ptr cinfo)
+{
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+
+ if (master->pub.is_dummy_pass) {
+#ifdef QUANT_2PASS_SUPPORTED
+ /* Final pass of 2-pass quantization */
+ master->pub.is_dummy_pass = FALSE;
+ (*cinfo->cquantize->start_pass) (cinfo, FALSE);
+ (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
+ (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
+#else
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+#endif /* QUANT_2PASS_SUPPORTED */
+ } else {
+ if (cinfo->quantize_colors && cinfo->colormap == NULL) {
+ /* Select new quantization method */
+ if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
+ cinfo->cquantize = master->quantizer_2pass;
+ master->pub.is_dummy_pass = TRUE;
+ } else if (cinfo->enable_1pass_quant) {
+ cinfo->cquantize = master->quantizer_1pass;
+ } else {
+ ERREXIT(cinfo, JERR_MODE_CHANGE);
+ }
+ }
+ (*cinfo->codec->start_output_pass) (cinfo);
+ if (! cinfo->raw_data_out) {
+ if (! master->using_merged_upsample)
+ (*cinfo->cconvert->start_pass) (cinfo);
+ (*cinfo->upsample->start_pass) (cinfo);
+ if (cinfo->quantize_colors)
+ (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
+ (*cinfo->post->start_pass) (cinfo,
+ (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
+ (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
+ }
+ }
+
+ /* Set up progress monitor's pass info if present */
+ if (cinfo->progress != NULL) {
+ cinfo->progress->completed_passes = master->pass_number;
+ cinfo->progress->total_passes = master->pass_number +
+ (master->pub.is_dummy_pass ? 2 : 1);
+ /* In buffered-image mode, we assume one more output pass if EOI not
+ * yet reached, but no more passes if EOI has been reached.
+ */
+ if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
+ cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
+ }
+ }
+}
+
+
+/*
+ * Finish up at end of an output pass.
+ */
+
+METHODDEF(void)
+finish_output_pass (j_decompress_ptr cinfo)
+{
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+
+ if (cinfo->quantize_colors)
+ (*cinfo->cquantize->finish_pass) (cinfo);
+ master->pass_number++;
+}
+
+
+#ifdef D_MULTISCAN_FILES_SUPPORTED
+
+/*
+ * Switch to a new external colormap between output passes.
+ */
+
+GLOBAL(void)
+jpeg_new_colormap (j_decompress_ptr cinfo)
+{
+ my_master_ptr master = (my_master_ptr) cinfo->master;
+
+ /* Prevent application from calling me at wrong times */
+ if (cinfo->global_state != DSTATE_BUFIMAGE)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ if (cinfo->quantize_colors && cinfo->enable_external_quant &&
+ cinfo->colormap != NULL) {
+ /* Select 2-pass quantizer for external colormap use */
+ cinfo->cquantize = master->quantizer_2pass;
+ /* Notify quantizer of colormap change */
+ (*cinfo->cquantize->new_color_map) (cinfo);
+ master->pub.is_dummy_pass = FALSE; /* just in case */
+ } else
+ ERREXIT(cinfo, JERR_MODE_CHANGE);
+}
+
+#endif /* D_MULTISCAN_FILES_SUPPORTED */
+
+
+/*
+ * Initialize master decompression control and select active modules.
+ * This is performed at the start of jpeg_start_decompress.
+ */
+
+GLOBAL(void)
+jinit_master_decompress (j_decompress_ptr cinfo)
+{
+ my_master_ptr master;
+
+ master = (my_master_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_decomp_master));
+ cinfo->master = (struct jpeg_decomp_master *) master;
+ master->pub.prepare_for_output_pass = prepare_for_output_pass;
+ master->pub.finish_output_pass = finish_output_pass;
+
+ master->pub.is_dummy_pass = FALSE;
+
+ master_selection(cinfo);
+}
--- /dev/null
+/*
+ * jdmerge.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains code for merged upsampling/color conversion.
+ *
+ * This file combines functions from jdsample.c and jdcolor.c;
+ * read those files first to understand what's going on.
+ *
+ * When the chroma components are to be upsampled by simple replication
+ * (ie, box filtering), we can save some work in color conversion by
+ * calculating all the output pixels corresponding to a pair of chroma
+ * samples at one time. In the conversion equations
+ * R = Y + K1 * Cr
+ * G = Y + K2 * Cb + K3 * Cr
+ * B = Y + K4 * Cb
+ * only the Y term varies among the group of pixels corresponding to a pair
+ * of chroma samples, so the rest of the terms can be calculated just once.
+ * At typical sampling ratios, this eliminates half or three-quarters of the
+ * multiplications needed for color conversion.
+ *
+ * This file currently provides implementations for the following cases:
+ * YCbCr => RGB color conversion only.
+ * Sampling ratios of 2h1v or 2h2v.
+ * No scaling needed at upsample time.
+ * Corner-aligned (non-CCIR601) sampling alignment.
+ * Other special cases could be added, but in most applications these are
+ * the only common cases. (For uncommon cases we fall back on the more
+ * general code in jdsample.c and jdcolor.c.)
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+#ifdef UPSAMPLE_MERGING_SUPPORTED
+
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_upsampler pub; /* public fields */
+
+ /* Pointer to routine to do actual upsampling/conversion of one row group */
+ JMETHOD(void, upmethod, (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
+ JSAMPARRAY output_buf));
+
+ /* Private state for YCC->RGB conversion */
+ int * Cr_r_tab; /* => table for Cr to R conversion */
+ int * Cb_b_tab; /* => table for Cb to B conversion */
+ INT32 * Cr_g_tab; /* => table for Cr to G conversion */
+ INT32 * Cb_g_tab; /* => table for Cb to G conversion */
+
+ /* For 2:1 vertical sampling, we produce two output rows at a time.
+ * We need a "spare" row buffer to hold the second output row if the
+ * application provides just a one-row buffer; we also use the spare
+ * to discard the dummy last row if the image height is odd.
+ */
+ JSAMPROW spare_row;
+ boolean spare_full; /* T if spare buffer is occupied */
+
+ JDIMENSION out_row_width; /* samples per output row */
+ JDIMENSION rows_to_go; /* counts rows remaining in image */
+} my_upsampler;
+
+typedef my_upsampler * my_upsample_ptr;
+
+#define SCALEBITS 16 /* speediest right-shift on some machines */
+#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
+#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
+
+
+/*
+ * Initialize tables for YCC->RGB colorspace conversion.
+ * This is taken directly from jdcolor.c; see that file for more info.
+ */
+
+LOCAL(void)
+build_ycc_rgb_table (j_decompress_ptr cinfo)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ int i;
+ INT32 x;
+ SHIFT_TEMPS
+
+ upsample->Cr_r_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ upsample->Cb_b_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ upsample->Cr_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+ upsample->Cb_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+
+ for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
+ /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
+ /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
+ /* Cr=>R value is nearest int to 1.40200 * x */
+ upsample->Cr_r_tab[i] = (int)
+ RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
+ /* Cb=>B value is nearest int to 1.77200 * x */
+ upsample->Cb_b_tab[i] = (int)
+ RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
+ /* Cr=>G value is scaled-up -0.71414 * x */
+ upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x;
+ /* Cb=>G value is scaled-up -0.34414 * x */
+ /* We also add in ONE_HALF so that need not do it in inner loop */
+ upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF;
+ }
+}
+
+
+/*
+ * Initialize for an upsampling pass.
+ */
+
+METHODDEF(void)
+start_pass_merged_upsample (j_decompress_ptr cinfo)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+
+ /* Mark the spare buffer empty */
+ upsample->spare_full = FALSE;
+ /* Initialize total-height counter for detecting bottom of image */
+ upsample->rows_to_go = cinfo->output_height;
+}
+
+
+/*
+ * Control routine to do upsampling (and color conversion).
+ *
+ * The control routine just handles the row buffering considerations.
+ */
+
+METHODDEF(void)
+merged_2v_upsample (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+/* 2:1 vertical sampling case: may need a spare row. */
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ JSAMPROW work_ptrs[2];
+ JDIMENSION num_rows; /* number of rows returned to caller */
+ (void)in_row_groups_avail;
+
+ if (upsample->spare_full) {
+ /* If we have a spare row saved from a previous cycle, just return it. */
+ jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0,
+ 1, upsample->out_row_width);
+ num_rows = 1;
+ upsample->spare_full = FALSE;
+ } else {
+ /* Figure number of rows to return to caller. */
+ num_rows = 2;
+ /* Not more than the distance to the end of the image. */
+ if (num_rows > upsample->rows_to_go)
+ num_rows = upsample->rows_to_go;
+ /* And not more than what the client can accept: */
+ out_rows_avail -= *out_row_ctr;
+ if (num_rows > out_rows_avail)
+ num_rows = out_rows_avail;
+ /* Create output pointer array for upsampler. */
+ work_ptrs[0] = output_buf[*out_row_ctr];
+ if (num_rows > 1) {
+ work_ptrs[1] = output_buf[*out_row_ctr + 1];
+ } else {
+ work_ptrs[1] = upsample->spare_row;
+ upsample->spare_full = TRUE;
+ }
+ /* Now do the upsampling. */
+ (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs);
+ }
+
+ /* Adjust counts */
+ *out_row_ctr += num_rows;
+ upsample->rows_to_go -= num_rows;
+ /* When the buffer is emptied, declare this input row group consumed */
+ if (! upsample->spare_full)
+ (*in_row_group_ctr)++;
+}
+
+
+METHODDEF(void)
+merged_1v_upsample (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+/* 1:1 vertical sampling case: much easier, never need a spare row. */
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ (void)in_row_groups_avail;(void)out_rows_avail;
+
+ /* Just do the upsampling. */
+ (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr,
+ output_buf + *out_row_ctr);
+ /* Adjust counts */
+ (*out_row_ctr)++;
+ (*in_row_group_ctr)++;
+}
+
+
+/*
+ * These are the routines invoked by the control routines to do
+ * the actual upsampling/conversion. One row group is processed per call.
+ *
+ * Note: since we may be writing directly into application-supplied buffers,
+ * we have to be honest about the output width; we can't assume the buffer
+ * has been rounded up to an even width.
+ */
+
+
+/*
+ * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical.
+ */
+
+METHODDEF(void)
+h2v1_merged_upsample (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
+ JSAMPARRAY output_buf)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ register int y, cred, cgreen, cblue;
+ int cb, cr;
+ register JSAMPROW outptr;
+ JSAMPROW inptr0, inptr1, inptr2;
+ JDIMENSION col;
+ /* copy these pointers into registers if possible */
+ register JSAMPLE * range_limit = cinfo->sample_range_limit;
+ int * Crrtab = upsample->Cr_r_tab;
+ int * Cbbtab = upsample->Cb_b_tab;
+ INT32 * Crgtab = upsample->Cr_g_tab;
+ INT32 * Cbgtab = upsample->Cb_g_tab;
+ SHIFT_TEMPS
+
+ inptr0 = input_buf[0][in_row_group_ctr];
+ inptr1 = input_buf[1][in_row_group_ctr];
+ inptr2 = input_buf[2][in_row_group_ctr];
+ outptr = output_buf[0];
+ /* Loop for each pair of output pixels */
+ for (col = cinfo->output_width >> 1; col > 0; col--) {
+ /* Do the chroma part of the calculation */
+ cb = GETJSAMPLE(*inptr1++);
+ cr = GETJSAMPLE(*inptr2++);
+ cred = Crrtab[cr];
+ cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
+ cblue = Cbbtab[cb];
+ /* Fetch 2 Y values and emit 2 pixels */
+ y = GETJSAMPLE(*inptr0++);
+ outptr[RGB_RED] = range_limit[y + cred];
+ outptr[RGB_GREEN] = range_limit[y + cgreen];
+ outptr[RGB_BLUE] = range_limit[y + cblue];
+ outptr += RGB_PIXELSIZE;
+ y = GETJSAMPLE(*inptr0++);
+ outptr[RGB_RED] = range_limit[y + cred];
+ outptr[RGB_GREEN] = range_limit[y + cgreen];
+ outptr[RGB_BLUE] = range_limit[y + cblue];
+ outptr += RGB_PIXELSIZE;
+ }
+ /* If image width is odd, do the last output column separately */
+ if (cinfo->output_width & 1) {
+ cb = GETJSAMPLE(*inptr1);
+ cr = GETJSAMPLE(*inptr2);
+ cred = Crrtab[cr];
+ cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
+ cblue = Cbbtab[cb];
+ y = GETJSAMPLE(*inptr0);
+ outptr[RGB_RED] = range_limit[y + cred];
+ outptr[RGB_GREEN] = range_limit[y + cgreen];
+ outptr[RGB_BLUE] = range_limit[y + cblue];
+ }
+}
+
+
+/*
+ * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical.
+ */
+
+METHODDEF(void)
+h2v2_merged_upsample (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
+ JSAMPARRAY output_buf)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ register int y, cred, cgreen, cblue;
+ int cb, cr;
+ register JSAMPROW outptr0, outptr1;
+ JSAMPROW inptr00, inptr01, inptr1, inptr2;
+ JDIMENSION col;
+ /* copy these pointers into registers if possible */
+ register JSAMPLE * range_limit = cinfo->sample_range_limit;
+ int * Crrtab = upsample->Cr_r_tab;
+ int * Cbbtab = upsample->Cb_b_tab;
+ INT32 * Crgtab = upsample->Cr_g_tab;
+ INT32 * Cbgtab = upsample->Cb_g_tab;
+ SHIFT_TEMPS
+
+ inptr00 = input_buf[0][in_row_group_ctr*2];
+ inptr01 = input_buf[0][in_row_group_ctr*2 + 1];
+ inptr1 = input_buf[1][in_row_group_ctr];
+ inptr2 = input_buf[2][in_row_group_ctr];
+ outptr0 = output_buf[0];
+ outptr1 = output_buf[1];
+ /* Loop for each group of output pixels */
+ for (col = cinfo->output_width >> 1; col > 0; col--) {
+ /* Do the chroma part of the calculation */
+ cb = GETJSAMPLE(*inptr1++);
+ cr = GETJSAMPLE(*inptr2++);
+ cred = Crrtab[cr];
+ cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
+ cblue = Cbbtab[cb];
+ /* Fetch 4 Y values and emit 4 pixels */
+ y = GETJSAMPLE(*inptr00++);
+ outptr0[RGB_RED] = range_limit[y + cred];
+ outptr0[RGB_GREEN] = range_limit[y + cgreen];
+ outptr0[RGB_BLUE] = range_limit[y + cblue];
+ outptr0 += RGB_PIXELSIZE;
+ y = GETJSAMPLE(*inptr00++);
+ outptr0[RGB_RED] = range_limit[y + cred];
+ outptr0[RGB_GREEN] = range_limit[y + cgreen];
+ outptr0[RGB_BLUE] = range_limit[y + cblue];
+ outptr0 += RGB_PIXELSIZE;
+ y = GETJSAMPLE(*inptr01++);
+ outptr1[RGB_RED] = range_limit[y + cred];
+ outptr1[RGB_GREEN] = range_limit[y + cgreen];
+ outptr1[RGB_BLUE] = range_limit[y + cblue];
+ outptr1 += RGB_PIXELSIZE;
+ y = GETJSAMPLE(*inptr01++);
+ outptr1[RGB_RED] = range_limit[y + cred];
+ outptr1[RGB_GREEN] = range_limit[y + cgreen];
+ outptr1[RGB_BLUE] = range_limit[y + cblue];
+ outptr1 += RGB_PIXELSIZE;
+ }
+ /* If image width is odd, do the last output column separately */
+ if (cinfo->output_width & 1) {
+ cb = GETJSAMPLE(*inptr1);
+ cr = GETJSAMPLE(*inptr2);
+ cred = Crrtab[cr];
+ cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
+ cblue = Cbbtab[cb];
+ y = GETJSAMPLE(*inptr00);
+ outptr0[RGB_RED] = range_limit[y + cred];
+ outptr0[RGB_GREEN] = range_limit[y + cgreen];
+ outptr0[RGB_BLUE] = range_limit[y + cblue];
+ y = GETJSAMPLE(*inptr01);
+ outptr1[RGB_RED] = range_limit[y + cred];
+ outptr1[RGB_GREEN] = range_limit[y + cgreen];
+ outptr1[RGB_BLUE] = range_limit[y + cblue];
+ }
+}
+
+
+/*
+ * Module initialization routine for merged upsampling/color conversion.
+ *
+ * NB: this is called under the conditions determined by use_merged_upsample()
+ * in jdmaster.c. That routine MUST correspond to the actual capabilities
+ * of this module; no safety checks are made here.
+ */
+
+GLOBAL(void)
+jinit_merged_upsampler (j_decompress_ptr cinfo)
+{
+ my_upsample_ptr upsample;
+
+ upsample = (my_upsample_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_upsampler));
+ cinfo->upsample = (struct jpeg_upsampler *) upsample;
+ upsample->pub.start_pass = start_pass_merged_upsample;
+ upsample->pub.need_context_rows = FALSE;
+
+ upsample->out_row_width = cinfo->output_width * cinfo->out_color_components;
+
+ if (cinfo->max_v_samp_factor == 2) {
+ upsample->pub.upsample = merged_2v_upsample;
+ upsample->upmethod = h2v2_merged_upsample;
+ /* Allocate a spare row buffer */
+ upsample->spare_row = (JSAMPROW)
+ (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (size_t) (upsample->out_row_width * SIZEOF(JSAMPLE)));
+ } else {
+ upsample->pub.upsample = merged_1v_upsample;
+ upsample->upmethod = h2v1_merged_upsample;
+ /* No spare row needed */
+ upsample->spare_row = NULL;
+ }
+
+ build_ycc_rgb_table(cinfo);
+}
+
+#endif /* UPSAMPLE_MERGING_SUPPORTED */
--- /dev/null
+/*
+ * jdphuff.c
+ *
+ * Copyright (C) 1995-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy decoding routines for progressive JPEG.
+ *
+ * Much of the complexity here has to do with supporting input suspension.
+ * If the data source module demands suspension, we want to be able to back
+ * up to the start of the current MCU. To do this, we copy state variables
+ * into local working storage, and update them back to the permanent
+ * storage only upon successful completion of an MCU.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy subsystem */
+#include "jdhuff.h" /* Declarations shared with jd*huff.c */
+
+
+#ifdef D_PROGRESSIVE_SUPPORTED
+
+/*
+ * Private entropy decoder object for progressive Huffman decoding.
+ *
+ * The savable_state subrecord contains fields that change within an MCU,
+ * but must not be updated permanently until we complete the MCU.
+ */
+
+typedef struct {
+ unsigned int EOBRUN; /* remaining EOBs in EOBRUN */
+ int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
+} savable_state;
+
+/* This macro is to work around compilers with missing or broken
+ * structure assignment. You'll need to fix this code if you have
+ * such a compiler and you change MAX_COMPS_IN_SCAN.
+ */
+
+#ifndef NO_STRUCT_ASSIGN
+#define ASSIGN_STATE(dest,src) ((dest) = (src))
+#else
+#if MAX_COMPS_IN_SCAN == 4
+#define ASSIGN_STATE(dest,src) \
+ ((dest).EOBRUN = (src).EOBRUN, \
+ (dest).last_dc_val[0] = (src).last_dc_val[0], \
+ (dest).last_dc_val[1] = (src).last_dc_val[1], \
+ (dest).last_dc_val[2] = (src).last_dc_val[2], \
+ (dest).last_dc_val[3] = (src).last_dc_val[3])
+#endif
+#endif
+
+
+typedef struct {
+ huffd_common_fields; /* Fields shared with other entropy decoders */
+
+ /* These fields are loaded into local variables at start of each MCU.
+ * In case of suspension, we exit WITHOUT updating them.
+ */
+ savable_state saved; /* Other state at start of MCU */
+
+ /* These fields are NOT loaded into local working state. */
+ unsigned int restarts_to_go; /* MCUs left in this restart interval */
+
+ /* Pointers to derived tables (these workspaces have image lifespan) */
+ d_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
+
+ d_derived_tbl * ac_derived_tbl; /* active table during an AC scan */
+} phuff_entropy_decoder;
+
+typedef phuff_entropy_decoder * phuff_entropy_ptr;
+
+/* Forward declarations */
+METHODDEF(boolean) decode_mcu_DC_first JPP((j_decompress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(boolean) decode_mcu_AC_first JPP((j_decompress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(boolean) decode_mcu_DC_refine JPP((j_decompress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+METHODDEF(boolean) decode_mcu_AC_refine JPP((j_decompress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+
+
+/*
+ * Initialize for a Huffman-compressed scan.
+ */
+
+METHODDEF(void)
+start_pass_phuff_decoder (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
+ boolean is_DC_band, bad;
+ int ci, coefi, tbl;
+ int *coef_bit_ptr;
+ jpeg_component_info * compptr;
+
+ is_DC_band = (cinfo->Ss == 0);
+
+ /* Validate scan parameters */
+ bad = FALSE;
+ if (is_DC_band) {
+ if (cinfo->Se != 0)
+ bad = TRUE;
+ } else {
+ /* need not check Ss/Se < 0 since they came from unsigned bytes */
+ if (cinfo->Ss > cinfo->Se || cinfo->Se >= DCTSIZE2)
+ bad = TRUE;
+ /* AC scans may have only one component */
+ if (cinfo->comps_in_scan != 1)
+ bad = TRUE;
+ }
+ if (cinfo->Ah != 0) {
+ /* Successive approximation refinement scan: must have Al = Ah-1. */
+ if (cinfo->Al != cinfo->Ah-1)
+ bad = TRUE;
+ }
+ if (cinfo->Al > 13) /* need not check for < 0 */
+ bad = TRUE;
+ /* Arguably the maximum Al value should be less than 13 for 8-bit precision,
+ * but the spec doesn't say so, and we try to be liberal about what we
+ * accept. Note: large Al values could result in out-of-range DC
+ * coefficients during early scans, leading to bizarre displays due to
+ * overflows in the IDCT math. But we won't crash.
+ */
+ if (bad)
+ ERREXIT4(cinfo, JERR_BAD_PROGRESSION,
+ cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);
+ /* Update progression status, and verify that scan order is legal.
+ * Note that inter-scan inconsistencies are treated as warnings
+ * not fatal errors ... not clear if this is right way to behave.
+ */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ int cindex = cinfo->cur_comp_info[ci]->component_index;
+ coef_bit_ptr = & cinfo->coef_bits[cindex][0];
+ if (!is_DC_band && coef_bit_ptr[0] < 0) /* AC without prior DC scan */
+ WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, 0);
+ for (coefi = cinfo->Ss; coefi <= cinfo->Se; coefi++) {
+ int expected = (coef_bit_ptr[coefi] < 0) ? 0 : coef_bit_ptr[coefi];
+ if (cinfo->Ah != expected)
+ WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, coefi);
+ coef_bit_ptr[coefi] = cinfo->Al;
+ }
+ }
+
+ /* Select MCU decoding routine */
+ if (cinfo->Ah == 0) {
+ if (is_DC_band)
+ lossyd->entropy_decode_mcu = decode_mcu_DC_first;
+ else
+ lossyd->entropy_decode_mcu = decode_mcu_AC_first;
+ } else {
+ if (is_DC_band)
+ lossyd->entropy_decode_mcu = decode_mcu_DC_refine;
+ else
+ lossyd->entropy_decode_mcu = decode_mcu_AC_refine;
+ }
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* Make sure requested tables are present, and compute derived tables.
+ * We may build same derived table more than once, but it's not expensive.
+ */
+ if (is_DC_band) {
+ if (cinfo->Ah == 0) { /* DC refinement needs no table */
+ tbl = compptr->dc_tbl_no;
+ jpeg_make_d_derived_tbl(cinfo, TRUE, tbl,
+ & entropy->derived_tbls[tbl]);
+ }
+ } else {
+ tbl = compptr->ac_tbl_no;
+ jpeg_make_d_derived_tbl(cinfo, FALSE, tbl,
+ & entropy->derived_tbls[tbl]);
+ /* remember the single active table */
+ entropy->ac_derived_tbl = entropy->derived_tbls[tbl];
+ }
+ /* Initialize DC predictions to 0 */
+ entropy->saved.last_dc_val[ci] = 0;
+ }
+
+ /* Initialize bitread state variables */
+ entropy->bitstate.bits_left = 0;
+ entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */
+ entropy->insufficient_data = FALSE;
+
+ /* Initialize private state variables */
+ entropy->saved.EOBRUN = 0;
+
+ /* Initialize restart counter */
+ entropy->restarts_to_go = cinfo->restart_interval;
+}
+
+
+/*
+ * Figure F.12: extend sign bit.
+ * On some machines, a shift and add will be faster than a table lookup.
+ */
+
+#ifdef AVOID_TABLES
+
+#define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x))
+
+#else
+
+#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x))
+
+static const int extend_test[16] = /* entry n is 2**(n-1) */
+ { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
+ 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
+
+static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
+ { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1,
+ ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1,
+ ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1,
+ ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 };
+
+#endif /* AVOID_TABLES */
+
+
+/*
+ * Check for a restart marker & resynchronize decoder.
+ * Returns FALSE if must suspend.
+ */
+
+LOCAL(boolean)
+process_restart (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
+ int ci;
+
+ /* Throw away any unused bits remaining in bit buffer; */
+ /* include any full bytes in next_marker's count of discarded bytes */
+ cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8;
+ entropy->bitstate.bits_left = 0;
+
+ /* Advance past the RSTn marker */
+ if (! (*cinfo->marker->read_restart_marker) (cinfo))
+ return FALSE;
+
+ /* Re-initialize DC predictions to 0 */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++)
+ entropy->saved.last_dc_val[ci] = 0;
+ /* Re-init EOB run count, too */
+ entropy->saved.EOBRUN = 0;
+
+ /* Reset restart counter */
+ entropy->restarts_to_go = cinfo->restart_interval;
+
+ /* Reset out-of-data flag, unless read_restart_marker left us smack up
+ * against a marker. In that case we will end up treating the next data
+ * segment as empty, and we can avoid producing bogus output pixels by
+ * leaving the flag set.
+ */
+ if (cinfo->unread_marker == 0)
+ entropy->insufficient_data = FALSE;
+
+ return TRUE;
+}
+
+
+/*
+ * Huffman MCU decoding.
+ * Each of these routines decodes and returns one MCU's worth of
+ * Huffman-compressed coefficients.
+ * The coefficients are reordered from zigzag order into natural array order,
+ * but are not dequantized.
+ *
+ * The i'th block of the MCU is stored into the block pointed to by
+ * MCU_data[i]. WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER.
+ *
+ * We return FALSE if data source requested suspension. In that case no
+ * changes have been made to permanent state. (Exception: some output
+ * coefficients may already have been assigned. This is harmless for
+ * spectral selection, since we'll just re-assign them on the next call.
+ * Successive approximation AC refinement has to be more careful, however.)
+ */
+
+/*
+ * MCU decoding for DC initial scan (either spectral selection,
+ * or first pass of successive approximation).
+ */
+
+METHODDEF(boolean)
+decode_mcu_DC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
+ int Al = cinfo->Al;
+ register int s, r;
+ int blkn, ci;
+ JBLOCKROW block;
+ BITREAD_STATE_VARS;
+ savable_state state;
+ d_derived_tbl * tbl;
+ jpeg_component_info * compptr;
+
+ /* Process restart marker if needed; may have to suspend */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! process_restart(cinfo))
+ return FALSE;
+ }
+
+ /* If we've run out of data, just leave the MCU set to zeroes.
+ * This way, we return uniform gray for the remainder of the segment.
+ */
+ if (! entropy->insufficient_data) {
+
+ /* Load up working state */
+ BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
+ ASSIGN_STATE(state, entropy->saved);
+
+ /* Outer loop handles each block in the MCU */
+
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ block = MCU_data[blkn];
+ ci = cinfo->MCU_membership[blkn];
+ compptr = cinfo->cur_comp_info[ci];
+ tbl = entropy->derived_tbls[compptr->dc_tbl_no];
+
+ /* Decode a single block's worth of coefficients */
+
+ /* Section F.2.2.1: decode the DC coefficient difference */
+ HUFF_DECODE(s, br_state, tbl, return FALSE, label1);
+ if (s) {
+ CHECK_BIT_BUFFER(br_state, s, return FALSE);
+ r = GET_BITS(s);
+ s = HUFF_EXTEND(r, s);
+ }
+
+ /* Convert DC difference to actual value, update last_dc_val */
+ s += state.last_dc_val[ci];
+ state.last_dc_val[ci] = s;
+ /* Scale and output the coefficient (assumes jpeg_natural_order[0]=0) */
+ (*block)[0] = (JCOEF) (s << Al);
+ }
+
+ /* Completed MCU, so update state */
+ BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
+ ASSIGN_STATE(entropy->saved, state);
+ }
+
+ /* Account for restart interval (no-op if not using restarts) */
+ entropy->restarts_to_go--;
+
+ return TRUE;
+}
+
+
+/*
+ * MCU decoding for AC initial scan (either spectral selection,
+ * or first pass of successive approximation).
+ */
+
+METHODDEF(boolean)
+decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
+ int Se = cinfo->Se;
+ int Al = cinfo->Al;
+ register int s, k, r;
+ unsigned int EOBRUN;
+ JBLOCKROW block;
+ BITREAD_STATE_VARS;
+ d_derived_tbl * tbl;
+
+ /* Process restart marker if needed; may have to suspend */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! process_restart(cinfo))
+ return FALSE;
+ }
+
+ /* If we've run out of data, just leave the MCU set to zeroes.
+ * This way, we return uniform gray for the remainder of the segment.
+ */
+ if (! entropy->insufficient_data) {
+
+ /* Load up working state.
+ * We can avoid loading/saving bitread state if in an EOB run.
+ */
+ EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */
+
+ /* There is always only one block per MCU */
+
+ if (EOBRUN > 0) /* if it's a band of zeroes... */
+ EOBRUN--; /* ...process it now (we do nothing) */
+ else {
+ BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
+ block = MCU_data[0];
+ tbl = entropy->ac_derived_tbl;
+
+ for (k = cinfo->Ss; k <= Se; k++) {
+ HUFF_DECODE(s, br_state, tbl, return FALSE, label2);
+ r = s >> 4;
+ s &= 15;
+ if (s) {
+ k += r;
+ CHECK_BIT_BUFFER(br_state, s, return FALSE);
+ r = GET_BITS(s);
+ s = HUFF_EXTEND(r, s);
+ /* Scale and output coefficient in natural (dezigzagged) order */
+ (*block)[jpeg_natural_order[k]] = (JCOEF) (s << Al);
+ } else {
+ if (r == 15) { /* ZRL */
+ k += 15; /* skip 15 zeroes in band */
+ } else { /* EOBr, run length is 2^r + appended bits */
+ EOBRUN = 1 << r;
+ if (r) { /* EOBr, r > 0 */
+ CHECK_BIT_BUFFER(br_state, r, return FALSE);
+ r = GET_BITS(r);
+ EOBRUN += r;
+ }
+ EOBRUN--; /* this band is processed at this moment */
+ break; /* force end-of-band */
+ }
+ }
+ }
+
+ BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
+ }
+
+ /* Completed MCU, so update state */
+ entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */
+ }
+
+ /* Account for restart interval (no-op if not using restarts) */
+ entropy->restarts_to_go--;
+
+ return TRUE;
+}
+
+
+/*
+ * MCU decoding for DC successive approximation refinement scan.
+ * Note: we assume such scans can be multi-component, although the spec
+ * is not very clear on the point.
+ */
+
+METHODDEF(boolean)
+decode_mcu_DC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
+ int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */
+ int blkn;
+ JBLOCKROW block;
+ BITREAD_STATE_VARS;
+
+ /* Process restart marker if needed; may have to suspend */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! process_restart(cinfo))
+ return FALSE;
+ }
+
+ /* Not worth the cycles to check insufficient_data here,
+ * since we will not change the data anyway if we read zeroes.
+ */
+
+ /* Load up working state */
+ BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
+
+ /* Outer loop handles each block in the MCU */
+
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ block = MCU_data[blkn];
+
+ /* Encoded data is simply the next bit of the two's-complement DC value */
+ CHECK_BIT_BUFFER(br_state, 1, return FALSE);
+ if (GET_BITS(1))
+ (*block)[0] |= p1;
+ /* Note: since we use |=, repeating the assignment later is safe */
+ }
+
+ /* Completed MCU, so update state */
+ BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
+
+ /* Account for restart interval (no-op if not using restarts) */
+ entropy->restarts_to_go--;
+
+ return TRUE;
+}
+
+
+/*
+ * MCU decoding for AC successive approximation refinement scan.
+ */
+
+METHODDEF(boolean)
+decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
+ int Se = cinfo->Se;
+ int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */
+ int m1 = (-1) << cinfo->Al; /* -1 in the bit position being coded */
+ register int s, k, r;
+ unsigned int EOBRUN;
+ JBLOCKROW block;
+ JCOEFPTR thiscoef;
+ BITREAD_STATE_VARS;
+ d_derived_tbl * tbl;
+ int num_newnz;
+ int newnz_pos[DCTSIZE2];
+
+ /* Process restart marker if needed; may have to suspend */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! process_restart(cinfo))
+ return FALSE;
+ }
+
+ /* If we've run out of data, don't modify the MCU.
+ */
+ if (! entropy->insufficient_data) {
+
+ /* Load up working state */
+ BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
+ EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */
+
+ /* There is always only one block per MCU */
+ block = MCU_data[0];
+ tbl = entropy->ac_derived_tbl;
+
+ /* If we are forced to suspend, we must undo the assignments to any newly
+ * nonzero coefficients in the block, because otherwise we'd get confused
+ * next time about which coefficients were already nonzero.
+ * But we need not undo addition of bits to already-nonzero coefficients;
+ * instead, we can test the current bit to see if we already did it.
+ */
+ num_newnz = 0;
+
+ /* initialize coefficient loop counter to start of band */
+ k = cinfo->Ss;
+
+ if (EOBRUN == 0) {
+ for (; k <= Se; k++) {
+ HUFF_DECODE(s, br_state, tbl, goto undoit, label3);
+ r = s >> 4;
+ s &= 15;
+ if (s) {
+ if (s != 1) /* size of new coef should always be 1 */
+ WARNMS(cinfo, JWRN_HUFF_BAD_CODE);
+ CHECK_BIT_BUFFER(br_state, 1, goto undoit);
+ if (GET_BITS(1))
+ s = p1; /* newly nonzero coef is positive */
+ else
+ s = m1; /* newly nonzero coef is negative */
+ } else {
+ if (r != 15) {
+ EOBRUN = 1 << r; /* EOBr, run length is 2^r + appended bits */
+ if (r) {
+ CHECK_BIT_BUFFER(br_state, r, goto undoit);
+ r = GET_BITS(r);
+ EOBRUN += r;
+ }
+ break; /* rest of block is handled by EOB logic */
+ }
+ /* note s = 0 for processing ZRL */
+ }
+ /* Advance over already-nonzero coefs and r still-zero coefs,
+ * appending correction bits to the nonzeroes. A correction bit is 1
+ * if the absolute value of the coefficient must be increased.
+ */
+ do {
+ thiscoef = *block + jpeg_natural_order[k];
+ if (*thiscoef != 0) {
+ CHECK_BIT_BUFFER(br_state, 1, goto undoit);
+ if (GET_BITS(1)) {
+ if ((*thiscoef & p1) == 0) { /* do nothing if already set it */
+ if (*thiscoef >= 0)
+ *thiscoef += p1;
+ else
+ *thiscoef += m1;
+ }
+ }
+ } else {
+ if (--r < 0)
+ break; /* reached target zero coefficient */
+ }
+ k++;
+ } while (k <= Se);
+ if (s) {
+ int pos = jpeg_natural_order[k];
+ /* Output newly nonzero coefficient */
+ (*block)[pos] = (JCOEF) s;
+ /* Remember its position in case we have to suspend */
+ newnz_pos[num_newnz++] = pos;
+ }
+ }
+ }
+
+ if (EOBRUN > 0) {
+ /* Scan any remaining coefficient positions after the end-of-band
+ * (the last newly nonzero coefficient, if any). Append a correction
+ * bit to each already-nonzero coefficient. A correction bit is 1
+ * if the absolute value of the coefficient must be increased.
+ */
+ for (; k <= Se; k++) {
+ thiscoef = *block + jpeg_natural_order[k];
+ if (*thiscoef != 0) {
+ CHECK_BIT_BUFFER(br_state, 1, goto undoit);
+ if (GET_BITS(1)) {
+ if ((*thiscoef & p1) == 0) { /* do nothing if already changed it */
+ if (*thiscoef >= 0)
+ *thiscoef += p1;
+ else
+ *thiscoef += m1;
+ }
+ }
+ }
+ }
+ /* Count one block completed in EOB run */
+ EOBRUN--;
+ }
+
+ /* Completed MCU, so update state */
+ BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
+ entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */
+ }
+
+ /* Account for restart interval (no-op if not using restarts) */
+ entropy->restarts_to_go--;
+
+ return TRUE;
+
+undoit:
+ /* Re-zero any output coefficients that we made newly nonzero */
+ while (num_newnz > 0)
+ (*block)[newnz_pos[--num_newnz]] = 0;
+
+ return FALSE;
+}
+
+
+/*
+ * Module initialization routine for progressive Huffman entropy decoding.
+ */
+
+GLOBAL(void)
+jinit_phuff_decoder (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ phuff_entropy_ptr entropy;
+ int *coef_bit_ptr;
+ int ci, i;
+
+ entropy = (phuff_entropy_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(phuff_entropy_decoder));
+ lossyd->entropy_private = (void *) entropy;
+ lossyd->entropy_start_pass = start_pass_phuff_decoder;
+
+ /* Mark derived tables unallocated */
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ entropy->derived_tbls[i] = NULL;
+ }
+
+ /* Create progression status table */
+ cinfo->coef_bits = (int (*)[DCTSIZE2])
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ cinfo->num_components*DCTSIZE2*SIZEOF(int));
+ coef_bit_ptr = & cinfo->coef_bits[0][0];
+ for (ci = 0; ci < cinfo->num_components; ci++)
+ for (i = 0; i < DCTSIZE2; i++)
+ *coef_bit_ptr++ = -1;
+}
+
+#endif /* D_PROGRESSIVE_SUPPORTED */
--- /dev/null
+/*
+ * jdpostct.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the decompression postprocessing controller.
+ * This controller manages the upsampling, color conversion, and color
+ * quantization/reduction steps; specifically, it controls the buffering
+ * between upsample/color conversion and color quantization/reduction.
+ *
+ * If no color quantization/reduction is required, then this module has no
+ * work to do, and it just hands off to the upsample/color conversion code.
+ * An integrated upsample/convert/quantize process would replace this module
+ * entirely.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private buffer controller object */
+
+typedef struct {
+ struct jpeg_d_post_controller pub; /* public fields */
+
+ /* Color quantization source buffer: this holds output data from
+ * the upsample/color conversion step to be passed to the quantizer.
+ * For two-pass color quantization, we need a full-image buffer;
+ * for one-pass operation, a strip buffer is sufficient.
+ */
+ jvirt_sarray_ptr whole_image; /* virtual array, or NULL if one-pass */
+ JSAMPARRAY buffer; /* strip buffer, or current strip of virtual */
+ JDIMENSION strip_height; /* buffer size in rows */
+ /* for two-pass mode only: */
+ JDIMENSION starting_row; /* row # of first row in current strip */
+ JDIMENSION next_row; /* index of next row to fill/empty in strip */
+} my_post_controller;
+
+typedef my_post_controller * my_post_ptr;
+
+
+/* Forward declarations */
+METHODDEF(void) post_process_1pass
+ JPP((j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail));
+#ifdef QUANT_2PASS_SUPPORTED
+METHODDEF(void) post_process_prepass
+ JPP((j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail));
+METHODDEF(void) post_process_2pass
+ JPP((j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail));
+#endif
+
+
+/*
+ * Initialize for a processing pass.
+ */
+
+METHODDEF(void)
+start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
+{
+ my_post_ptr post = (my_post_ptr) cinfo->post;
+
+ switch (pass_mode) {
+ case JBUF_PASS_THRU:
+ if (cinfo->quantize_colors) {
+ /* Single-pass processing with color quantization. */
+ post->pub.post_process_data = post_process_1pass;
+ /* We could be doing buffered-image output before starting a 2-pass
+ * color quantization; in that case, jinit_d_post_controller did not
+ * allocate a strip buffer. Use the virtual-array buffer as workspace.
+ */
+ if (post->buffer == NULL) {
+ post->buffer = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, post->whole_image,
+ (JDIMENSION) 0, post->strip_height, TRUE);
+ }
+ } else {
+ /* For single-pass processing without color quantization,
+ * I have no work to do; just call the upsampler directly.
+ */
+ post->pub.post_process_data = cinfo->upsample->upsample;
+ }
+ break;
+#ifdef QUANT_2PASS_SUPPORTED
+ case JBUF_SAVE_AND_PASS:
+ /* First pass of 2-pass quantization */
+ if (post->whole_image == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ post->pub.post_process_data = post_process_prepass;
+ break;
+ case JBUF_CRANK_DEST:
+ /* Second pass of 2-pass quantization */
+ if (post->whole_image == NULL)
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ post->pub.post_process_data = post_process_2pass;
+ break;
+#endif /* QUANT_2PASS_SUPPORTED */
+ default:
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+ break;
+ }
+ post->starting_row = post->next_row = 0;
+}
+
+
+/*
+ * Process some data in the one-pass (strip buffer) case.
+ * This is used for color precision reduction as well as one-pass quantization.
+ */
+
+METHODDEF(void)
+post_process_1pass (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ my_post_ptr post = (my_post_ptr) cinfo->post;
+ JDIMENSION num_rows, max_rows;
+
+ /* Fill the buffer, but not more than what we can dump out in one go. */
+ /* Note we rely on the upsampler to detect bottom of image. */
+ max_rows = out_rows_avail - *out_row_ctr;
+ if (max_rows > post->strip_height)
+ max_rows = post->strip_height;
+ num_rows = 0;
+ (*cinfo->upsample->upsample) (cinfo,
+ input_buf, in_row_group_ctr, in_row_groups_avail,
+ post->buffer, &num_rows, max_rows);
+ /* Quantize and emit data. */
+ (*cinfo->cquantize->color_quantize) (cinfo,
+ post->buffer, output_buf + *out_row_ctr, (int) num_rows);
+ *out_row_ctr += num_rows;
+}
+
+
+#ifdef QUANT_2PASS_SUPPORTED
+
+/*
+ * Process some data in the first pass of 2-pass quantization.
+ */
+
+METHODDEF(void)
+post_process_prepass (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ my_post_ptr post = (my_post_ptr) cinfo->post;
+ JDIMENSION old_next_row, num_rows;
+ (void)output_buf;(void)out_rows_avail;
+
+ /* Reposition virtual buffer if at start of strip. */
+ if (post->next_row == 0) {
+ post->buffer = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, post->whole_image,
+ post->starting_row, post->strip_height, TRUE);
+ }
+
+ /* Upsample some data (up to a strip height's worth). */
+ old_next_row = post->next_row;
+ (*cinfo->upsample->upsample) (cinfo,
+ input_buf, in_row_group_ctr, in_row_groups_avail,
+ post->buffer, &post->next_row, post->strip_height);
+
+ /* Allow quantizer to scan new data. No data is emitted, */
+ /* but we advance out_row_ctr so outer loop can tell when we're done. */
+ if (post->next_row > old_next_row) {
+ num_rows = post->next_row - old_next_row;
+ (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
+ (JSAMPARRAY) NULL, (int) num_rows);
+ *out_row_ctr += num_rows;
+ }
+
+ /* Advance if we filled the strip. */
+ if (post->next_row >= post->strip_height) {
+ post->starting_row += post->strip_height;
+ post->next_row = 0;
+ }
+}
+
+
+/*
+ * Process some data in the second pass of 2-pass quantization.
+ */
+
+METHODDEF(void)
+post_process_2pass (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ my_post_ptr post = (my_post_ptr) cinfo->post;
+ JDIMENSION num_rows, max_rows;
+ (void)input_buf;(void)in_row_group_ctr;(void)in_row_groups_avail;
+
+ /* Reposition virtual buffer if at start of strip. */
+ if (post->next_row == 0) {
+ post->buffer = (*cinfo->mem->access_virt_sarray)
+ ((j_common_ptr) cinfo, post->whole_image,
+ post->starting_row, post->strip_height, FALSE);
+ }
+
+ /* Determine number of rows to emit. */
+ num_rows = post->strip_height - post->next_row; /* available in strip */
+ max_rows = out_rows_avail - *out_row_ctr; /* available in output area */
+ if (num_rows > max_rows)
+ num_rows = max_rows;
+ /* We have to check bottom of image here, can't depend on upsampler. */
+ max_rows = cinfo->output_height - post->starting_row;
+ if (num_rows > max_rows)
+ num_rows = max_rows;
+
+ /* Quantize and emit data. */
+ (*cinfo->cquantize->color_quantize) (cinfo,
+ post->buffer + post->next_row, output_buf + *out_row_ctr,
+ (int) num_rows);
+ *out_row_ctr += num_rows;
+
+ /* Advance if we filled the strip. */
+ post->next_row += num_rows;
+ if (post->next_row >= post->strip_height) {
+ post->starting_row += post->strip_height;
+ post->next_row = 0;
+ }
+}
+
+#endif /* QUANT_2PASS_SUPPORTED */
+
+
+/*
+ * Initialize postprocessing controller.
+ */
+
+GLOBAL(void)
+jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
+{
+ my_post_ptr post;
+
+ post = (my_post_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_post_controller));
+ cinfo->post = (struct jpeg_d_post_controller *) post;
+ post->pub.start_pass = start_pass_dpost;
+ post->whole_image = NULL; /* flag for no virtual arrays */
+ post->buffer = NULL; /* flag for no strip buffer */
+
+ /* Create the quantization buffer, if needed */
+ if (cinfo->quantize_colors) {
+ /* The buffer strip height is max_v_samp_factor, which is typically
+ * an efficient number of rows for upsampling to return.
+ * (In the presence of output rescaling, we might want to be smarter?)
+ */
+ post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
+ if (need_full_buffer) {
+ /* Two-pass color quantization: need full-image storage. */
+ /* We round up the number of rows to a multiple of the strip height. */
+#ifdef QUANT_2PASS_SUPPORTED
+ post->whole_image = (*cinfo->mem->request_virt_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
+ cinfo->output_width * cinfo->out_color_components,
+ (JDIMENSION) jround_up((long) cinfo->output_height,
+ (long) post->strip_height),
+ post->strip_height);
+#else
+ ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
+#endif /* QUANT_2PASS_SUPPORTED */
+ } else {
+ /* One-pass color quantization: just make a strip buffer. */
+ post->buffer = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ cinfo->output_width * cinfo->out_color_components,
+ post->strip_height);
+ }
+ }
+}
--- /dev/null
+/*
+ * jdpred.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains sample undifferencing (reconstruction) for lossless JPEG.
+ *
+ * In order to avoid paying the performance penalty of having to check the
+ * predictor being used and the row being processed for each call of the
+ * undifferencer, and to promote optimization, we have separate undifferencing
+ * functions for each case.
+ *
+ * We are able to avoid duplicating source code by implementing the predictors
+ * and undifferencers as macros. Each of the undifferencing functions are
+ * simply wrappers around an UNDIFFERENCE macro with the appropriate PREDICTOR
+ * macro passed as an argument.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+
+
+#ifdef D_LOSSLESS_SUPPORTED
+
+/* Predictor for the first column of the first row: 2^(P-Pt-1) */
+#define INITIAL_PREDICTORx (1 << (cinfo->data_precision - cinfo->Al - 1))
+
+/* Predictor for the first column of the remaining rows: Rb */
+#define INITIAL_PREDICTOR2 GETJSAMPLE(prev_row[0])
+
+
+/*
+ * 1-Dimensional undifferencer routine.
+ *
+ * This macro implements the 1-D horizontal predictor (1). INITIAL_PREDICTOR
+ * is used as the special case predictor for the first column, which must be
+ * either INITIAL_PREDICTOR2 or INITIAL_PREDICTORx. The remaining samples
+ * use PREDICTOR1.
+ *
+ * The reconstructed sample is supposed to be calculated modulo 2^16, so we
+ * logically AND the result with 0xFFFF.
+*/
+
+#define UNDIFFERENCE_1D(INITIAL_PREDICTOR) \
+ unsigned int xindex; \
+ int Ra; \
+ \
+ Ra = (diff_buf[0] + INITIAL_PREDICTOR) & 0xFFFF; \
+ undiff_buf[0] = Ra; \
+ \
+ for (xindex = 1; xindex < width; xindex++) { \
+ Ra = (diff_buf[xindex] + PREDICTOR1) & 0xFFFF; \
+ undiff_buf[xindex] = Ra; \
+ }
+
+/*
+ * 2-Dimensional undifferencer routine.
+ *
+ * This macro implements the 2-D horizontal predictors (#2-7). PREDICTOR2 is
+ * used as the special case predictor for the first column. The remaining
+ * samples use PREDICTOR, which is a function of Ra, Rb, Rc.
+ *
+ * Because prev_row and output_buf may point to the same storage area (in an
+ * interleaved image with Vi=1, for example), we must take care to buffer Rb/Rc
+ * before writing the current reconstructed sample value into output_buf.
+ *
+ * The reconstructed sample is supposed to be calculated modulo 2^16, so we
+ * logically AND the result with 0xFFFF.
+ */
+
+#define UNDIFFERENCE_2D(PREDICTOR) \
+ unsigned int xindex; \
+ int Ra, Rb, Rc; \
+ \
+ Rb = GETJSAMPLE(prev_row[0]); \
+ Ra = (diff_buf[0] + PREDICTOR2) & 0xFFFF; \
+ undiff_buf[0] = Ra; \
+ \
+ for (xindex = 1; xindex < width; xindex++) { \
+ Rc = Rb; \
+ Rb = GETJSAMPLE(prev_row[xindex]); \
+ Ra = (diff_buf[xindex] + PREDICTOR) & 0xFFFF; \
+ undiff_buf[xindex] = Ra; \
+ }
+
+
+/*
+ * Undifferencers for the all rows but the first in a scan or restart interval.
+ * The first sample in the row is undifferenced using the vertical
+ * predictor (2). The rest of the samples are undifferenced using the
+ * predictor specified in the scan header.
+ */
+
+METHODDEF(void)
+jpeg_undifference1(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ UNDIFFERENCE_1D(INITIAL_PREDICTOR2);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+METHODDEF(void)
+jpeg_undifference2(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ UNDIFFERENCE_2D(PREDICTOR2);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+METHODDEF(void)
+jpeg_undifference3(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ UNDIFFERENCE_2D(PREDICTOR3);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+METHODDEF(void)
+jpeg_undifference4(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ UNDIFFERENCE_2D(PREDICTOR4);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+METHODDEF(void)
+jpeg_undifference5(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ SHIFT_TEMPS
+ UNDIFFERENCE_2D(PREDICTOR5);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+METHODDEF(void)
+jpeg_undifference6(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ SHIFT_TEMPS
+ UNDIFFERENCE_2D(PREDICTOR6);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+METHODDEF(void)
+jpeg_undifference7(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ SHIFT_TEMPS
+ UNDIFFERENCE_2D(PREDICTOR7);
+ (void)cinfo;(void)comp_index;(void)diff_buf;(void)prev_row;(void)undiff_buf;(void)width;
+}
+
+
+/*
+ * Undifferencer for the first row in a scan or restart interval. The first
+ * sample in the row is undifferenced using the special predictor constant
+ * x=2^(P-Pt-1). The rest of the samples are undifferenced using the
+ * 1-D horizontal predictor (1).
+ */
+
+METHODDEF(void)
+jpeg_undifference_first_row(j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+
+ UNDIFFERENCE_1D(INITIAL_PREDICTORx);
+ (void)prev_row;
+
+ /*
+ * Now that we have undifferenced the first row, we want to use the
+ * undifferencer which corresponds to the predictor specified in the
+ * scan header.
+ */
+ switch (cinfo->Ss) {
+ case 1:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference1;
+ break;
+ case 2:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference2;
+ break;
+ case 3:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference3;
+ break;
+ case 4:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference4;
+ break;
+ case 5:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference5;
+ break;
+ case 6:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference6;
+ break;
+ case 7:
+ losslsd->predict_undifference[comp_index] = jpeg_undifference7;
+ break;
+ }
+}
+
+
+/*
+ * Initialize for an input processing pass.
+ */
+
+METHODDEF(void)
+predict_start_pass (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ int ci;
+
+ /* Check that the scan parameters Ss, Se, Ah, Al are OK for lossless JPEG.
+ *
+ * Ss is the predictor selection value (psv). Legal values for sequential
+ * lossless JPEG are: 1 <= psv <= 7.
+ *
+ * Se and Ah are not used and should be zero.
+ *
+ * Al specifies the point transform (Pt). Legal values are: 0 <= Pt <= 15.
+ */
+ if (cinfo->Ss < 1 || cinfo->Ss > 7 ||
+ cinfo->Se != 0 || cinfo->Ah != 0 ||
+ cinfo->Al > 15) /* need not check for < 0 */
+ ERREXIT4(cinfo, JERR_BAD_LOSSLESS,
+ cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);
+
+ /* Set undifference functions to first row function */
+ for (ci = 0; ci < cinfo->num_components; ci++)
+ losslsd->predict_undifference[ci] = jpeg_undifference_first_row;
+}
+
+
+/*
+ * Module initialization routine for the undifferencer.
+ */
+
+GLOBAL(void)
+jinit_undifferencer (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+
+ losslsd->predict_start_pass = predict_start_pass;
+ losslsd->predict_process_restart = predict_start_pass;
+}
+
+#endif /* D_LOSSLESS_SUPPORTED */
+
--- /dev/null
+/*
+ * jdsample.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains upsampling routines.
+ *
+ * Upsampling input data is counted in "row groups". A row group
+ * is defined to be (v_samp_factor * codec_data_unit / min_codec_data_unit)
+ * sample rows of each component. Upsampling will normally produce
+ * max_v_samp_factor pixel rows from each row group (but this could vary
+ * if the upsampler is applying a scale factor of its own).
+ *
+ * An excellent reference for image resampling is
+ * Digital Image Warping, George Wolberg, 1990.
+ * Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Pointer to routine to upsample a single component */
+typedef JMETHOD(void, upsample1_ptr,
+ (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr));
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_upsampler pub; /* public fields */
+
+ /* Color conversion buffer. When using separate upsampling and color
+ * conversion steps, this buffer holds one upsampled row group until it
+ * has been color converted and output.
+ * Note: we do not allocate any storage for component(s) which are full-size,
+ * ie do not need rescaling. The corresponding entry of color_buf[] is
+ * simply set to point to the input data array, thereby avoiding copying.
+ */
+ JSAMPARRAY color_buf[MAX_COMPONENTS];
+
+ /* Per-component upsampling method pointers */
+ upsample1_ptr methods[MAX_COMPONENTS];
+
+ int next_row_out; /* counts rows emitted from color_buf */
+ JDIMENSION rows_to_go; /* counts rows remaining in image */
+
+ /* Height of an input row group for each component. */
+ int rowgroup_height[MAX_COMPONENTS];
+
+ /* These arrays save pixel expansion factors so that int_expand need not
+ * recompute them each time. They are unused for other upsampling methods.
+ */
+ UINT8 h_expand[MAX_COMPONENTS];
+ UINT8 v_expand[MAX_COMPONENTS];
+} my_upsampler;
+
+typedef my_upsampler * my_upsample_ptr;
+
+
+/*
+ * Initialize for an upsampling pass.
+ */
+
+METHODDEF(void)
+start_pass_upsample (j_decompress_ptr cinfo)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+
+ /* Mark the conversion buffer empty */
+ upsample->next_row_out = cinfo->max_v_samp_factor;
+ /* Initialize total-height counter for detecting bottom of image */
+ upsample->rows_to_go = cinfo->output_height;
+}
+
+
+/*
+ * Control routine to do upsampling (and color conversion).
+ *
+ * In this version we upsample each component independently.
+ * We upsample one row group into the conversion buffer, then apply
+ * color conversion a row at a time.
+ */
+
+METHODDEF(void)
+sep_upsample (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ int ci;
+ jpeg_component_info * compptr;
+ JDIMENSION num_rows;
+ (void)in_row_groups_avail;
+
+ /* Fill the conversion buffer, if it's empty */
+ if (upsample->next_row_out >= cinfo->max_v_samp_factor) {
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Invoke per-component upsample method. Notice we pass a POINTER
+ * to color_buf[ci], so that fullsize_upsample can change it.
+ */
+ (*upsample->methods[ci]) (cinfo, compptr,
+ input_buf[ci] + (*in_row_group_ctr * upsample->rowgroup_height[ci]),
+ upsample->color_buf + ci);
+ }
+ upsample->next_row_out = 0;
+ }
+
+ /* Color-convert and emit rows */
+
+ /* How many we have in the buffer: */
+ num_rows = (JDIMENSION) (cinfo->max_v_samp_factor - upsample->next_row_out);
+ /* Not more than the distance to the end of the image. Need this test
+ * in case the image height is not a multiple of max_v_samp_factor:
+ */
+ if (num_rows > upsample->rows_to_go)
+ num_rows = upsample->rows_to_go;
+ /* And not more than what the client can accept: */
+ out_rows_avail -= *out_row_ctr;
+ if (num_rows > out_rows_avail)
+ num_rows = out_rows_avail;
+
+ (*cinfo->cconvert->color_convert) (cinfo, upsample->color_buf,
+ (JDIMENSION) upsample->next_row_out,
+ output_buf + *out_row_ctr,
+ (int) num_rows);
+
+ /* Adjust counts */
+ *out_row_ctr += num_rows;
+ upsample->rows_to_go -= num_rows;
+ upsample->next_row_out += num_rows;
+ /* When the buffer is emptied, declare this input row group consumed */
+ if (upsample->next_row_out >= cinfo->max_v_samp_factor)
+ (*in_row_group_ctr)++;
+}
+
+
+/*
+ * These are the routines invoked by sep_upsample to upsample pixel values
+ * of a single component. One row group is processed per call.
+ */
+
+
+/*
+ * For full-size components, we just make color_buf[ci] point at the
+ * input buffer, and thus avoid copying any data. Note that this is
+ * safe only because sep_upsample doesn't declare the input row group
+ * "consumed" until we are done color converting and emitting it.
+ */
+
+METHODDEF(void)
+fullsize_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ (void)cinfo;(void)compptr;
+ *output_data_ptr = input_data;
+}
+
+
+/*
+ * This is a no-op version used for "uninteresting" components.
+ * These components will not be referenced by color conversion.
+ */
+
+METHODDEF(void)
+noop_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ (void)cinfo;(void)compptr;(void)input_data;
+ *output_data_ptr = NULL; /* safety check */
+}
+
+
+/*
+ * This version handles any integral sampling ratios.
+ * This is not used for typical JPEG files, so it need not be fast.
+ * Nor, for that matter, is it particularly accurate: the algorithm is
+ * simple replication of the input pixel onto the corresponding output
+ * pixels. The hi-falutin sampling literature refers to this as a
+ * "box filter". A box filter tends to introduce visible artifacts,
+ * so if you are actually going to use 3:1 or 4:1 sampling ratios
+ * you would be well advised to improve this code.
+ */
+
+METHODDEF(void)
+int_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
+ JSAMPARRAY output_data = *output_data_ptr;
+ register JSAMPROW inptr, outptr;
+ register JSAMPLE invalue;
+ register int h;
+ JSAMPROW outend;
+ int h_expand, v_expand;
+ int inrow, outrow;
+
+ h_expand = upsample->h_expand[compptr->component_index];
+ v_expand = upsample->v_expand[compptr->component_index];
+
+ inrow = outrow = 0;
+ while (outrow < cinfo->max_v_samp_factor) {
+ /* Generate one output row with proper horizontal expansion */
+ inptr = input_data[inrow];
+ outptr = output_data[outrow];
+ outend = outptr + cinfo->output_width;
+ while (outptr < outend) {
+ invalue = *inptr++; /* don't need GETJSAMPLE() here */
+ for (h = h_expand; h > 0; h--) {
+ *outptr++ = invalue;
+ }
+ }
+ /* Generate any additional output rows by duplicating the first one */
+ if (v_expand > 1) {
+ jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
+ v_expand-1, cinfo->output_width);
+ }
+ inrow++;
+ outrow += v_expand;
+ }
+}
+
+
+/*
+ * Fast processing for the common case of 2:1 horizontal and 1:1 vertical.
+ * It's still a box filter.
+ */
+
+METHODDEF(void)
+h2v1_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ JSAMPARRAY output_data = *output_data_ptr;
+ register JSAMPROW inptr, outptr;
+ register JSAMPLE invalue;
+ JSAMPROW outend;
+ int inrow;
+ (void)compptr;
+
+ for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
+ inptr = input_data[inrow];
+ outptr = output_data[inrow];
+ outend = outptr + cinfo->output_width;
+ while (outptr < outend) {
+ invalue = *inptr++; /* don't need GETJSAMPLE() here */
+ *outptr++ = invalue;
+ *outptr++ = invalue;
+ }
+ }
+}
+
+
+/*
+ * Fast processing for the common case of 2:1 horizontal and 2:1 vertical.
+ * It's still a box filter.
+ */
+
+METHODDEF(void)
+h2v2_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ JSAMPARRAY output_data = *output_data_ptr;
+ register JSAMPROW inptr, outptr;
+ register JSAMPLE invalue;
+ JSAMPROW outend;
+ int inrow, outrow;
+ (void)compptr;
+
+ inrow = outrow = 0;
+ while (outrow < cinfo->max_v_samp_factor) {
+ inptr = input_data[inrow];
+ outptr = output_data[outrow];
+ outend = outptr + cinfo->output_width;
+ while (outptr < outend) {
+ invalue = *inptr++; /* don't need GETJSAMPLE() here */
+ *outptr++ = invalue;
+ *outptr++ = invalue;
+ }
+ jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
+ 1, cinfo->output_width);
+ inrow++;
+ outrow += 2;
+ }
+}
+
+
+/*
+ * Fancy processing for the common case of 2:1 horizontal and 1:1 vertical.
+ *
+ * The upsampling algorithm is linear interpolation between pixel centers,
+ * also known as a "triangle filter". This is a good compromise between
+ * speed and visual quality. The centers of the output pixels are 1/4 and 3/4
+ * of the way between input pixel centers.
+ *
+ * A note about the "bias" calculations: when rounding fractional values to
+ * integer, we do not want to always round 0.5 up to the next integer.
+ * If we did that, we'd introduce a noticeable bias towards larger values.
+ * Instead, this code is arranged so that 0.5 will be rounded up or down at
+ * alternate pixel locations (a simple ordered dither pattern).
+ */
+
+METHODDEF(void)
+h2v1_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ JSAMPARRAY output_data = *output_data_ptr;
+ register JSAMPROW inptr, outptr;
+ register int invalue;
+ register JDIMENSION colctr;
+ int inrow;
+
+ for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
+ inptr = input_data[inrow];
+ outptr = output_data[inrow];
+ /* Special case for first column */
+ invalue = GETJSAMPLE(*inptr++);
+ *outptr++ = (JSAMPLE) invalue;
+ *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(*inptr) + 2) >> 2);
+
+ for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {
+ /* General case: 3/4 * nearer pixel + 1/4 * further pixel */
+ invalue = GETJSAMPLE(*inptr++) * 3;
+ *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(inptr[-2]) + 1) >> 2);
+ *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(*inptr) + 2) >> 2);
+ }
+
+ /* Special case for last column */
+ invalue = GETJSAMPLE(*inptr);
+ *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(inptr[-1]) + 1) >> 2);
+ *outptr++ = (JSAMPLE) invalue;
+ }
+}
+
+
+/*
+ * Fancy processing for the common case of 2:1 horizontal and 2:1 vertical.
+ * Again a triangle filter; see comments for h2v1 case, above.
+ *
+ * It is OK for us to reference the adjacent input rows because we demanded
+ * context from the main buffer controller (see initialization code).
+ */
+
+METHODDEF(void)
+h2v2_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
+{
+ JSAMPARRAY output_data = *output_data_ptr;
+ register JSAMPROW inptr0, inptr1, outptr;
+#if BITS_IN_JSAMPLE == 8
+ register int thiscolsum, lastcolsum, nextcolsum;
+#else
+ register INT32 thiscolsum, lastcolsum, nextcolsum;
+#endif
+ register JDIMENSION colctr;
+ int inrow, outrow, v;
+
+ inrow = outrow = 0;
+ while (outrow < cinfo->max_v_samp_factor) {
+ for (v = 0; v < 2; v++) {
+ /* inptr0 points to nearest input row, inptr1 points to next nearest */
+ inptr0 = input_data[inrow];
+ if (v == 0) /* next nearest is row above */
+ inptr1 = input_data[inrow-1];
+ else /* next nearest is row below */
+ inptr1 = input_data[inrow+1];
+ outptr = output_data[outrow++];
+
+ /* Special case for first column */
+ thiscolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
+ nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
+ *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 8) >> 4);
+ *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);
+ lastcolsum = thiscolsum; thiscolsum = nextcolsum;
+
+ for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {
+ /* General case: 3/4 * nearer pixel + 1/4 * further pixel in each */
+ /* dimension, thus 9/16, 3/16, 3/16, 1/16 overall */
+ nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
+ *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);
+ *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);
+ lastcolsum = thiscolsum; thiscolsum = nextcolsum;
+ }
+
+ /* Special case for last column */
+ *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);
+ *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 7) >> 4);
+ }
+ inrow++;
+ }
+}
+
+
+/*
+ * Module initialization routine for upsampling.
+ */
+
+GLOBAL(void)
+jinit_upsampler (j_decompress_ptr cinfo)
+{
+ my_upsample_ptr upsample;
+ int ci;
+ jpeg_component_info * compptr;
+ boolean need_buffer, do_fancy;
+ int h_in_group, v_in_group, h_out_group, v_out_group;
+
+ upsample = (my_upsample_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_upsampler));
+ cinfo->upsample = (struct jpeg_upsampler *) upsample;
+ upsample->pub.start_pass = start_pass_upsample;
+ upsample->pub.upsample = sep_upsample;
+ upsample->pub.need_context_rows = FALSE; /* until we find out differently */
+
+ if (cinfo->CCIR601_sampling) /* this isn't supported */
+ ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
+
+ /* jdmainct.c doesn't support context rows when min_codec_data_unit = 1,
+ * so don't ask for it.
+ */
+ do_fancy = cinfo->do_fancy_upsampling && cinfo->min_codec_data_unit > 1;
+
+ /* Verify we can handle the sampling factors, select per-component methods,
+ * and create storage as needed.
+ */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Compute size of an "input group" after IDCT scaling. This many samples
+ * are to be converted to max_h_samp_factor * max_v_samp_factor pixels.
+ */
+ h_in_group = (compptr->h_samp_factor * compptr->codec_data_unit) /
+ cinfo->min_codec_data_unit;
+ v_in_group = (compptr->v_samp_factor * compptr->codec_data_unit) /
+ cinfo->min_codec_data_unit;
+ h_out_group = cinfo->max_h_samp_factor;
+ v_out_group = cinfo->max_v_samp_factor;
+ upsample->rowgroup_height[ci] = v_in_group; /* save for use later */
+ need_buffer = TRUE;
+ if (! compptr->component_needed) {
+ /* Don't bother to upsample an uninteresting component. */
+ upsample->methods[ci] = noop_upsample;
+ need_buffer = FALSE;
+ } else if (h_in_group == h_out_group && v_in_group == v_out_group) {
+ /* Fullsize components can be processed without any work. */
+ upsample->methods[ci] = fullsize_upsample;
+ need_buffer = FALSE;
+ } else if (h_in_group * 2 == h_out_group &&
+ v_in_group == v_out_group) {
+ /* Special cases for 2h1v upsampling */
+ if (do_fancy && compptr->downsampled_width > 2)
+ upsample->methods[ci] = h2v1_fancy_upsample;
+ else
+ upsample->methods[ci] = h2v1_upsample;
+ } else if (h_in_group * 2 == h_out_group &&
+ v_in_group * 2 == v_out_group) {
+ /* Special cases for 2h2v upsampling */
+ if (do_fancy && compptr->downsampled_width > 2) {
+ upsample->methods[ci] = h2v2_fancy_upsample;
+ upsample->pub.need_context_rows = TRUE;
+ } else
+ upsample->methods[ci] = h2v2_upsample;
+ } else if ((h_out_group % h_in_group) == 0 &&
+ (v_out_group % v_in_group) == 0) {
+ /* Generic integral-factors upsampling method */
+ upsample->methods[ci] = int_upsample;
+ upsample->h_expand[ci] = (UINT8) (h_out_group / h_in_group);
+ upsample->v_expand[ci] = (UINT8) (v_out_group / v_in_group);
+ } else
+ ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
+ if (need_buffer) {
+ upsample->color_buf[ci] = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) jround_up((long) cinfo->output_width,
+ (long) cinfo->max_h_samp_factor),
+ (JDIMENSION) cinfo->max_v_samp_factor);
+ }
+ }
+}
--- /dev/null
+/*
+ * jdscale.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains sample scaling for lossless JPEG. This is a
+ * combination of upscaling the undifferenced sample by 2^Pt and downscaling
+ * the sample to fit into JSAMPLE.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h" /* Private declarations for lossless codec */
+
+
+#ifdef D_LOSSLESS_SUPPORTED
+
+/*
+ * Private scaler object for lossless decoding.
+ */
+
+typedef struct {
+ int scale_factor;
+} scaler;
+
+typedef scaler * scaler_ptr;
+
+
+/*
+ * Scalers for packing sample differences into JSAMPLEs.
+ */
+
+METHODDEF(void)
+simple_upscale(j_decompress_ptr cinfo,
+ JDIFFROW diff_buf, JSAMPROW output_buf,
+ JDIMENSION width)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ scaler_ptr scaler = (scaler_ptr) losslsd->scaler_private;
+ int scale_factor = scaler->scale_factor;
+ unsigned int xindex;
+
+ for (xindex = 0; xindex < width; xindex++)
+ output_buf[xindex] = (JSAMPLE) (diff_buf[xindex] << scale_factor);
+}
+
+METHODDEF(void)
+simple_downscale(j_decompress_ptr cinfo,
+ JDIFFROW diff_buf, JSAMPROW output_buf,
+ JDIMENSION width)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ scaler_ptr scaler = (scaler_ptr) losslsd->scaler_private;
+ int scale_factor = scaler->scale_factor;
+ unsigned int xindex;
+ SHIFT_TEMPS
+
+ for (xindex = 0; xindex < width; xindex++)
+ output_buf[xindex] = (JSAMPLE) RIGHT_SHIFT(diff_buf[xindex], scale_factor);
+}
+
+METHODDEF(void)
+noscale(j_decompress_ptr cinfo,
+ JDIFFROW diff_buf, JSAMPROW output_buf,
+ JDIMENSION width)
+{
+ unsigned int xindex;
+ (void)cinfo;
+
+ for (xindex = 0; xindex < width; xindex++)
+ output_buf[xindex] = (JSAMPLE) diff_buf[xindex];
+}
+
+
+METHODDEF(void)
+scaler_start_pass (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ scaler_ptr scaler = (scaler_ptr) losslsd->scaler_private;
+ int downscale;
+
+ /*
+ * Downscale by the difference in the input vs. output precision. If the
+ * output precision >= input precision, then do not downscale.
+ */
+ downscale = BITS_IN_JSAMPLE < cinfo->data_precision ?
+ cinfo->data_precision - BITS_IN_JSAMPLE : 0;
+
+ scaler->scale_factor = cinfo->Al - downscale;
+
+ /* Set scaler functions based on scale_factor (positive = left shift) */
+ if (scaler->scale_factor > 0)
+ losslsd->scaler_scale = simple_upscale;
+ else if (scaler->scale_factor < 0) {
+ scaler->scale_factor = -scaler->scale_factor;
+ losslsd->scaler_scale = simple_downscale;
+ }
+ else
+ losslsd->scaler_scale = noscale;
+}
+
+
+GLOBAL(void)
+jinit_d_scaler (j_decompress_ptr cinfo)
+{
+ j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
+ scaler_ptr scaler;
+
+ scaler = (scaler_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(scaler));
+ losslsd->scaler_private = (void *) scaler;
+ losslsd->scaler_start_pass = scaler_start_pass;
+}
+
+#endif /* D_LOSSLESS_SUPPORTED */
+
--- /dev/null
+/*
+ * jdshuff.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains Huffman entropy decoding routines for sequential JPEG.
+ *
+ * Much of the complexity here has to do with supporting input suspension.
+ * If the data source module demands suspension, we want to be able to back
+ * up to the start of the current MCU. To do this, we copy state variables
+ * into local working storage, and update them back to the permanent
+ * storage only upon successful completion of an MCU.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h" /* Private declarations for lossy codec */
+#include "jdhuff.h" /* Declarations shared with jd*huff.c */
+
+
+/*
+ * Private entropy decoder object for Huffman decoding.
+ *
+ * The savable_state subrecord contains fields that change within an MCU,
+ * but must not be updated permanently until we complete the MCU.
+ */
+
+typedef struct {
+ int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
+} savable_state;
+
+/* This macro is to work around compilers with missing or broken
+ * structure assignment. You'll need to fix this code if you have
+ * such a compiler and you change MAX_COMPS_IN_SCAN.
+ */
+
+#ifndef NO_STRUCT_ASSIGN
+#define ASSIGN_STATE(dest,src) ((dest) = (src))
+#else
+#if MAX_COMPS_IN_SCAN == 4
+#define ASSIGN_STATE(dest,src) \
+ ((dest).last_dc_val[0] = (src).last_dc_val[0], \
+ (dest).last_dc_val[1] = (src).last_dc_val[1], \
+ (dest).last_dc_val[2] = (src).last_dc_val[2], \
+ (dest).last_dc_val[3] = (src).last_dc_val[3])
+#endif
+#endif
+
+
+typedef struct {
+ huffd_common_fields; /* Fields shared with other entropy decoders */
+
+ /* These fields are loaded into local variables at start of each MCU.
+ * In case of suspension, we exit WITHOUT updating them.
+ */
+ savable_state saved; /* Other state at start of MCU */
+
+ /* These fields are NOT loaded into local working state. */
+ unsigned int restarts_to_go; /* MCUs left in this restart interval */
+
+ /* Pointers to derived tables (these workspaces have image lifespan) */
+ d_derived_tbl * dc_derived_tbls[NUM_HUFF_TBLS];
+ d_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS];
+
+ /* Precalculated info set up by start_pass for use in decode_mcu: */
+
+ /* Pointers to derived tables to be used for each block within an MCU */
+ d_derived_tbl * dc_cur_tbls[D_MAX_DATA_UNITS_IN_MCU];
+ d_derived_tbl * ac_cur_tbls[D_MAX_DATA_UNITS_IN_MCU];
+ /* Whether we care about the DC and AC coefficient values for each block */
+ boolean dc_needed[D_MAX_DATA_UNITS_IN_MCU];
+ boolean ac_needed[D_MAX_DATA_UNITS_IN_MCU];
+} shuff_entropy_decoder;
+
+typedef shuff_entropy_decoder * shuff_entropy_ptr;
+
+
+/*
+ * Initialize for a Huffman-compressed scan.
+ */
+
+METHODDEF(void)
+start_pass_huff_decoder (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyd->entropy_private;
+ int ci, blkn, dctbl, actbl;
+ jpeg_component_info * compptr;
+
+ /* Check that the scan parameters Ss, Se, Ah/Al are OK for sequential JPEG.
+ * This ought to be an error condition, but we make it a warning because
+ * there are some baseline files out there with all zeroes in these bytes.
+ */
+ if (cinfo->Ss != 0 || cinfo->Se != DCTSIZE2-1 ||
+ cinfo->Ah != 0 || cinfo->Al != 0)
+ WARNMS(cinfo, JWRN_NOT_SEQUENTIAL);
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ dctbl = compptr->dc_tbl_no;
+ actbl = compptr->ac_tbl_no;
+ /* Compute derived values for Huffman tables */
+ /* We may do this more than once for a table, but it's not expensive */
+ jpeg_make_d_derived_tbl(cinfo, TRUE, dctbl,
+ & entropy->dc_derived_tbls[dctbl]);
+ jpeg_make_d_derived_tbl(cinfo, FALSE, actbl,
+ & entropy->ac_derived_tbls[actbl]);
+ /* Initialize DC predictions to 0 */
+ entropy->saved.last_dc_val[ci] = 0;
+ }
+
+ /* Precalculate decoding info for each block in an MCU of this scan */
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ ci = cinfo->MCU_membership[blkn];
+ compptr = cinfo->cur_comp_info[ci];
+ /* Precalculate which table to use for each block */
+ entropy->dc_cur_tbls[blkn] = entropy->dc_derived_tbls[compptr->dc_tbl_no];
+ entropy->ac_cur_tbls[blkn] = entropy->ac_derived_tbls[compptr->ac_tbl_no];
+ /* Decide whether we really care about the coefficient values */
+ if (compptr->component_needed) {
+ entropy->dc_needed[blkn] = TRUE;
+ /* we don't need the ACs if producing a 1/8th-size image */
+ entropy->ac_needed[blkn] = (compptr->codec_data_unit > 1);
+ } else {
+ entropy->dc_needed[blkn] = entropy->ac_needed[blkn] = FALSE;
+ }
+ }
+
+ /* Initialize bitread state variables */
+ entropy->bitstate.bits_left = 0;
+ entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */
+ entropy->insufficient_data = FALSE;
+
+ /* Initialize restart counter */
+ entropy->restarts_to_go = cinfo->restart_interval;
+}
+
+
+/*
+ * Figure F.12: extend sign bit.
+ * On some machines, a shift and add will be faster than a table lookup.
+ */
+
+#ifdef AVOID_TABLES
+
+#define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x))
+
+#else
+
+#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x))
+
+static const int extend_test[16] = /* entry n is 2**(n-1) */
+ { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
+ 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
+
+static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
+ { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1,
+ ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1,
+ ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1,
+ ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 };
+
+#endif /* AVOID_TABLES */
+
+
+/*
+ * Check for a restart marker & resynchronize decoder.
+ * Returns FALSE if must suspend.
+ */
+
+LOCAL(boolean)
+process_restart (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyd->entropy_private;
+ int ci;
+
+ /* Throw away any unused bits remaining in bit buffer; */
+ /* include any full bytes in next_marker's count of discarded bytes */
+ cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8;
+ entropy->bitstate.bits_left = 0;
+
+ /* Advance past the RSTn marker */
+ if (! (*cinfo->marker->read_restart_marker) (cinfo))
+ return FALSE;
+
+ /* Re-initialize DC predictions to 0 */
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++)
+ entropy->saved.last_dc_val[ci] = 0;
+
+ /* Reset restart counter */
+ entropy->restarts_to_go = cinfo->restart_interval;
+
+ /* Reset out-of-data flag, unless read_restart_marker left us smack up
+ * against a marker. In that case we will end up treating the next data
+ * segment as empty, and we can avoid producing bogus output pixels by
+ * leaving the flag set.
+ */
+ if (cinfo->unread_marker == 0)
+ entropy->insufficient_data = FALSE;
+
+ return TRUE;
+}
+
+
+/*
+ * Decode and return one MCU's worth of Huffman-compressed coefficients.
+ * The coefficients are reordered from zigzag order into natural array order,
+ * but are not dequantized.
+ *
+ * The i'th block of the MCU is stored into the block pointed to by
+ * MCU_data[i]. WE ASSUME THIS AREA HAS BEEN ZEROED BY THE CALLER.
+ * (Wholesale zeroing is usually a little faster than retail...)
+ *
+ * Returns FALSE if data source requested suspension. In that case no
+ * changes have been made to permanent state. (Exception: some output
+ * coefficients may already have been assigned. This is harmless for
+ * this module, since we'll just re-assign them on the next call.)
+ */
+
+METHODDEF(boolean)
+decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy = (shuff_entropy_ptr) lossyd->entropy_private;
+ int blkn;
+ BITREAD_STATE_VARS;
+ savable_state state;
+
+ /* Process restart marker if needed; may have to suspend */
+ if (cinfo->restart_interval) {
+ if (entropy->restarts_to_go == 0)
+ if (! process_restart(cinfo))
+ return FALSE;
+ }
+
+ /* If we've run out of data, just leave the MCU set to zeroes.
+ * This way, we return uniform gray for the remainder of the segment.
+ */
+ if (! entropy->insufficient_data) {
+
+ /* Load up working state */
+ BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
+ ASSIGN_STATE(state, entropy->saved);
+
+ /* Outer loop handles each block in the MCU */
+
+ for (blkn = 0; blkn < cinfo->data_units_in_MCU; blkn++) {
+ JBLOCKROW block = MCU_data[blkn];
+ d_derived_tbl * dctbl = entropy->dc_cur_tbls[blkn];
+ d_derived_tbl * actbl = entropy->ac_cur_tbls[blkn];
+ register int s, k, r;
+
+ /* Decode a single block's worth of coefficients */
+
+ /* Section F.2.2.1: decode the DC coefficient difference */
+ HUFF_DECODE(s, br_state, dctbl, return FALSE, label1);
+ if (s) {
+ CHECK_BIT_BUFFER(br_state, s, return FALSE);
+ r = GET_BITS(s);
+ s = HUFF_EXTEND(r, s);
+ }
+
+ if (entropy->dc_needed[blkn]) {
+ /* Convert DC difference to actual value, update last_dc_val */
+ int ci = cinfo->MCU_membership[blkn];
+ s += state.last_dc_val[ci];
+ state.last_dc_val[ci] = s;
+ /* Output the DC coefficient (assumes jpeg_natural_order[0] = 0) */
+ (*block)[0] = (JCOEF) s;
+ }
+
+ if (entropy->ac_needed[blkn]) {
+
+ /* Section F.2.2.2: decode the AC coefficients */
+ /* Since zeroes are skipped, output area must be cleared beforehand */
+ for (k = 1; k < DCTSIZE2; k++) {
+ HUFF_DECODE(s, br_state, actbl, return FALSE, label2);
+
+ r = s >> 4;
+ s &= 15;
+
+ if (s) {
+ k += r;
+ CHECK_BIT_BUFFER(br_state, s, return FALSE);
+ r = GET_BITS(s);
+ s = HUFF_EXTEND(r, s);
+ /* Output coefficient in natural (dezigzagged) order.
+ * Note: the extra entries in jpeg_natural_order[] will save us
+ * if k >= DCTSIZE2, which could happen if the data is corrupted.
+ */
+ (*block)[jpeg_natural_order[k]] = (JCOEF) s;
+ } else {
+ if (r != 15)
+ break;
+ k += 15;
+ }
+ }
+
+ } else {
+
+ /* Section F.2.2.2: decode the AC coefficients */
+ /* In this path we just discard the values */
+ for (k = 1; k < DCTSIZE2; k++) {
+ HUFF_DECODE(s, br_state, actbl, return FALSE, label3);
+
+ r = s >> 4;
+ s &= 15;
+
+ if (s) {
+ k += r;
+ CHECK_BIT_BUFFER(br_state, s, return FALSE);
+ DROP_BITS(s);
+ } else {
+ if (r != 15)
+ break;
+ k += 15;
+ }
+ }
+
+ }
+ }
+
+ /* Completed MCU, so update state */
+ BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
+ ASSIGN_STATE(entropy->saved, state);
+ }
+
+ /* Account for restart interval (no-op if not using restarts) */
+ entropy->restarts_to_go--;
+
+ return TRUE;
+}
+
+
+/*
+ * Module initialization routine for Huffman entropy decoding.
+ */
+
+GLOBAL(void)
+jinit_shuff_decoder (j_decompress_ptr cinfo)
+{
+ j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
+ shuff_entropy_ptr entropy;
+ int i;
+
+ entropy = (shuff_entropy_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(shuff_entropy_decoder));
+ lossyd->entropy_private = (void *) entropy;
+ lossyd->entropy_start_pass = start_pass_huff_decoder;
+ lossyd->entropy_decode_mcu = decode_mcu;
+
+ /* Mark tables unallocated */
+ for (i = 0; i < NUM_HUFF_TBLS; i++) {
+ entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL;
+ }
+}
--- /dev/null
+/*
+ * jdtrans.c
+ *
+ * Copyright (C) 1995-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains library routines for transcoding decompression,
+ * that is, reading raw DCT coefficient arrays from an input JPEG file.
+ * The routines in jdapimin.c will also be needed by a transcoder.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossy.h"
+
+
+/* Forward declarations */
+LOCAL(void) transdecode_master_selection JPP((j_decompress_ptr cinfo));
+
+
+/*
+ * Read the coefficient arrays from a JPEG file.
+ * jpeg_read_header must be completed before calling this.
+ *
+ * The entire image is read into a set of virtual coefficient-block arrays,
+ * one per component. The return value is a pointer to the array of
+ * virtual-array descriptors. These can be manipulated directly via the
+ * JPEG memory manager, or handed off to jpeg_write_coefficients().
+ * To release the memory occupied by the virtual arrays, call
+ * jpeg_finish_decompress() when done with the data.
+ *
+ * An alternative usage is to simply obtain access to the coefficient arrays
+ * during a buffered-image-mode decompression operation. This is allowed
+ * after any jpeg_finish_output() call. The arrays can be accessed until
+ * jpeg_finish_decompress() is called. (Note that any call to the library
+ * may reposition the arrays, so don't rely on access_virt_barray() results
+ * to stay valid across library calls.)
+ *
+ * Returns NULL if suspended. This case need be checked only if
+ * a suspending data source is used.
+ */
+
+GLOBAL(jvirt_barray_ptr *)
+jpeg_read_coefficients (j_decompress_ptr cinfo)
+{
+ /* j_lossy_d_ptr decomp; */
+
+ /* Can't read coefficients from lossless streams */
+ if (cinfo->process == JPROC_LOSSLESS) {
+ ERREXIT(cinfo, JERR_CANT_TRANSCODE);
+ return NULL;
+ }
+
+ if (cinfo->global_state == DSTATE_READY) {
+ /* First call: initialize active modules */
+ transdecode_master_selection(cinfo);
+ cinfo->global_state = DSTATE_RDCOEFS;
+ }
+ if (cinfo->global_state == DSTATE_RDCOEFS) {
+ /* Absorb whole file into the coef buffer */
+ for (;;) {
+ int retcode;
+ /* Call progress monitor hook if present */
+ if (cinfo->progress != NULL)
+ (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
+ /* Absorb some more input */
+ retcode = (*cinfo->inputctl->consume_input) (cinfo);
+ if (retcode == JPEG_SUSPENDED)
+ return NULL;
+ if (retcode == JPEG_REACHED_EOI)
+ break;
+ /* Advance progress counter if appropriate */
+ if (cinfo->progress != NULL &&
+ (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {
+ if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {
+ /* startup underestimated number of scans; ratchet up one scan */
+ cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;
+ }
+ }
+ }
+ /* Set state so that jpeg_finish_decompress does the right thing */
+ cinfo->global_state = DSTATE_STOPPING;
+ }
+ /* At this point we should be in state DSTATE_STOPPING if being used
+ * standalone, or in state DSTATE_BUFIMAGE if being invoked to get access
+ * to the coefficients during a full buffered-image-mode decompression.
+ */
+ if ((cinfo->global_state == DSTATE_STOPPING ||
+ cinfo->global_state == DSTATE_BUFIMAGE) && cinfo->buffered_image) {
+ return ((j_lossy_d_ptr) cinfo->codec)->coef_arrays;
+ }
+ /* Oops, improper usage */
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+ return NULL; /* keep compiler happy */
+}
+
+
+/*
+ * Master selection of decompression modules for transcoding.
+ * This substitutes for jdmaster.c's initialization of the full decompressor.
+ */
+
+LOCAL(void)
+transdecode_master_selection (j_decompress_ptr cinfo)
+{
+ /* This is effectively a buffered-image operation. */
+ cinfo->buffered_image = TRUE;
+
+ /* Initialize decompression codec */
+ jinit_d_codec(cinfo);
+
+ /* We can now tell the memory manager to allocate virtual arrays. */
+ (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
+
+ /* Initialize input side of decompressor to consume first scan. */
+ (*cinfo->inputctl->start_input_pass) (cinfo);
+
+ /* Initialize progress monitoring. */
+ if (cinfo->progress != NULL) {
+ int nscans;
+ /* Estimate number of scans to set pass_limit. */
+ if (cinfo->process == JPROC_PROGRESSIVE) {
+ /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
+ nscans = 2 + 3 * cinfo->num_components;
+ } else if (cinfo->inputctl->has_multiple_scans) {
+ /* For a nonprogressive multiscan file, estimate 1 scan per component. */
+ nscans = cinfo->num_components;
+ } else {
+ nscans = 1;
+ }
+ cinfo->progress->pass_counter = 0L;
+ cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
+ cinfo->progress->completed_passes = 0;
+ cinfo->progress->total_passes = 1;
+ }
+}
--- /dev/null
+/*
+ * jerror.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains simple error-reporting and trace-message routines.
+ * These are suitable for Unix-like systems and others where writing to
+ * stderr is the right thing to do. Many applications will want to replace
+ * some or all of these routines.
+ *
+ * If you define USE_WINDOWS_MESSAGEBOX in jconfig.h or in the makefile,
+ * you get a Windows-specific hack to display error messages in a dialog box.
+ * It ain't much, but it beats dropping error messages into the bit bucket,
+ * which is what happens to output to stderr under most Windows C compilers.
+ *
+ * These routines are used by both the compression and decompression code.
+ */
+
+/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jversion.h"
+#include "jerror.h"
+
+#ifdef USE_WINDOWS_MESSAGEBOX
+#include <windows.h>
+#endif
+
+#ifndef EXIT_FAILURE /* define exit() codes if not provided */
+#define EXIT_FAILURE 1
+#endif
+
+
+/*
+ * Create the message string table.
+ * We do this from the master message list in jerror.h by re-reading
+ * jerror.h with a suitable definition for macro JMESSAGE.
+ * The message table is made an external symbol just in case any applications
+ * want to refer to it directly.
+ */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_std_message_table jMsgTable
+#endif
+
+#define JMESSAGE(code,string) string ,
+
+const char * const jpeg_std_message_table[] = {
+#include "jerror.h"
+ NULL
+};
+
+
+/*
+ * Error exit handler: must not return to caller.
+ *
+ * Applications may override this if they want to get control back after
+ * an error. Typically one would longjmp somewhere instead of exiting.
+ * The setjmp buffer can be made a private field within an expanded error
+ * handler object. Note that the info needed to generate an error message
+ * is stored in the error object, so you can generate the message now or
+ * later, at your convenience.
+ * You should make sure that the JPEG object is cleaned up (with jpeg_abort
+ * or jpeg_destroy) at some point.
+ */
+
+METHODDEF(void)
+error_exit (j_common_ptr cinfo)
+{
+ /* Always display the message */
+ (*cinfo->err->output_message) (cinfo);
+
+ /* Let the memory manager delete any temp files before we die */
+ jpeg_destroy(cinfo);
+
+ exit(EXIT_FAILURE);
+}
+
+
+/*
+ * Actual output of an error or trace message.
+ * Applications may override this method to send JPEG messages somewhere
+ * other than stderr.
+ *
+ * On Windows, printing to stderr is generally completely useless,
+ * so we provide optional code to produce an error-dialog popup.
+ * Most Windows applications will still prefer to override this routine,
+ * but if they don't, it'll do something at least marginally useful.
+ *
+ * NOTE: to use the library in an environment that doesn't support the
+ * C stdio library, you may have to delete the call to fprintf() entirely,
+ * not just not use this routine.
+ */
+
+METHODDEF(void)
+output_message (j_common_ptr cinfo)
+{
+ char buffer[JMSG_LENGTH_MAX];
+
+ /* Create the message */
+ (*cinfo->err->format_message) (cinfo, buffer);
+
+#ifdef USE_WINDOWS_MESSAGEBOX
+ /* Display it in a message dialog box */
+ MessageBox(GetActiveWindow(), buffer, "JPEG Library Error",
+ MB_OK | MB_ICONERROR);
+#else
+ /* Send it to stderr, adding a newline */
+ fprintf(stderr, "%s\n", buffer);
+#endif
+}
+
+
+/*
+ * Decide whether to emit a trace or warning message.
+ * msg_level is one of:
+ * -1: recoverable corrupt-data warning, may want to abort.
+ * 0: important advisory messages (always display to user).
+ * 1: first level of tracing detail.
+ * 2,3,...: successively more detailed tracing messages.
+ * An application might override this method if it wanted to abort on warnings
+ * or change the policy about which messages to display.
+ */
+
+METHODDEF(void)
+emit_message (j_common_ptr cinfo, int msg_level)
+{
+ struct jpeg_error_mgr * err = cinfo->err;
+
+ if (msg_level < 0) {
+ /* It's a warning message. Since corrupt files may generate many warnings,
+ * the policy implemented here is to show only the first warning,
+ * unless trace_level >= 3.
+ */
+ if (err->num_warnings == 0 || err->trace_level >= 3)
+ (*err->output_message) (cinfo);
+ /* Always count warnings in num_warnings. */
+ err->num_warnings++;
+ } else {
+ /* It's a trace message. Show it if trace_level >= msg_level. */
+ if (err->trace_level >= msg_level)
+ (*err->output_message) (cinfo);
+ }
+}
+
+
+/*
+ * Format a message string for the most recent JPEG error or message.
+ * The message is stored into buffer, which should be at least JMSG_LENGTH_MAX
+ * characters. Note that no '\n' character is added to the string.
+ * Few applications should need to override this method.
+ */
+
+METHODDEF(void)
+format_message (j_common_ptr cinfo, char * buffer)
+{
+ struct jpeg_error_mgr * err = cinfo->err;
+ int msg_code = err->msg_code;
+ const char * msgtext = NULL;
+ const char * msgptr;
+ char ch;
+ boolean isstring;
+
+ /* Look up message string in proper table */
+ if (msg_code > 0 && msg_code <= err->last_jpeg_message) {
+ msgtext = err->jpeg_message_table[msg_code];
+ } else if (err->addon_message_table != NULL &&
+ msg_code >= err->first_addon_message &&
+ msg_code <= err->last_addon_message) {
+ msgtext = err->addon_message_table[msg_code - err->first_addon_message];
+ }
+
+ /* Defend against bogus message number */
+ if (msgtext == NULL) {
+ err->msg_parm.i[0] = msg_code;
+ msgtext = err->jpeg_message_table[0];
+ }
+
+ /* Check for string parameter, as indicated by %s in the message text */
+ isstring = FALSE;
+ msgptr = msgtext;
+ while ((ch = *msgptr++) != '\0') {
+ if (ch == '%') {
+ if (*msgptr == 's') isstring = TRUE;
+ break;
+ }
+ }
+
+ /* Format the message into the passed buffer */
+ if (isstring)
+ sprintf(buffer, msgtext, err->msg_parm.s);
+ else
+ sprintf(buffer, msgtext,
+ err->msg_parm.i[0], err->msg_parm.i[1],
+ err->msg_parm.i[2], err->msg_parm.i[3],
+ err->msg_parm.i[4], err->msg_parm.i[5],
+ err->msg_parm.i[6], err->msg_parm.i[7]);
+}
+
+
+/*
+ * Reset error state variables at start of a new image.
+ * This is called during compression startup to reset trace/error
+ * processing to default state, without losing any application-specific
+ * method pointers. An application might possibly want to override
+ * this method if it has additional error processing state.
+ */
+
+METHODDEF(void)
+reset_error_mgr (j_common_ptr cinfo)
+{
+ cinfo->err->num_warnings = 0;
+ /* trace_level is not reset since it is an application-supplied parameter */
+ cinfo->err->msg_code = 0; /* may be useful as a flag for "no error" */
+}
+
+
+/*
+ * Fill in the standard error-handling methods in a jpeg_error_mgr object.
+ * Typical call is:
+ * struct jpeg_compress_struct cinfo;
+ * struct jpeg_error_mgr err;
+ *
+ * cinfo.err = jpeg_std_error(&err);
+ * after which the application may override some of the methods.
+ */
+
+GLOBAL(struct jpeg_error_mgr *)
+jpeg_std_error (struct jpeg_error_mgr * err)
+{
+ err->error_exit = error_exit;
+ err->emit_message = emit_message;
+ err->output_message = output_message;
+ err->format_message = format_message;
+ err->reset_error_mgr = reset_error_mgr;
+
+ err->trace_level = 0; /* default = no tracing */
+ err->num_warnings = 0; /* no warnings emitted yet */
+ err->msg_code = 0; /* may be useful as a flag for "no error" */
+
+ /* Initialize message table pointers */
+ err->jpeg_message_table = jpeg_std_message_table;
+ err->last_jpeg_message = (int) JMSG_LASTMSGCODE - 1;
+
+ err->addon_message_table = NULL;
+ err->first_addon_message = 0; /* for safety */
+ err->last_addon_message = 0;
+
+ return err;
+}
--- /dev/null
+/*
+ * jerror.h
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file defines the error and message codes for the JPEG library.
+ * Edit this file to add new codes, or to translate the message strings to
+ * some other language.
+ * A set of error-reporting macros are defined too. Some applications using
+ * the JPEG library may wish to include this file to get the error codes
+ * and/or the macros.
+ */
+
+/*
+ * To define the enum list of message codes, include this file without
+ * defining macro JMESSAGE. To create a message string table, include it
+ * again with a suitable JMESSAGE definition (see jerror.c for an example).
+ */
+#ifndef JMESSAGE
+#ifndef JERROR_H
+/* First time through, define the enum list */
+#define JMAKE_ENUM_LIST
+#else
+/* Repeated inclusions of this file are no-ops unless JMESSAGE is defined */
+#define JMESSAGE(code,string)
+#endif /* JERROR_H */
+#endif /* JMESSAGE */
+
+#ifdef JMAKE_ENUM_LIST
+
+typedef enum {
+
+#define JMESSAGE(code,string) code ,
+
+#endif /* JMAKE_ENUM_LIST */
+
+JMESSAGE(JMSG_NOMESSAGE, "Bogus message code %d") /* Must be first entry! */
+
+/* For maintenance convenience, list is alphabetical by message code name */
+JMESSAGE(JERR_ARITH_NOTIMPL,
+ "Sorry, there are legal restrictions on arithmetic coding")
+JMESSAGE(JERR_BAD_ALIGN_TYPE, "ALIGN_TYPE is wrong, please fix")
+JMESSAGE(JERR_BAD_ALLOC_CHUNK, "MAX_ALLOC_CHUNK is wrong, please fix")
+JMESSAGE(JERR_BAD_BUFFER_MODE, "Bogus buffer control mode")
+JMESSAGE(JERR_BAD_COMPONENT_ID, "Invalid component ID %d in SOS")
+JMESSAGE(JERR_BAD_DCT_COEF, "DCT coefficient out of range")
+JMESSAGE(JERR_BAD_DCTSIZE, "IDCT output block size %d not supported")
+JMESSAGE(JERR_BAD_DIFF, "spatial difference out of range")
+JMESSAGE(JERR_BAD_HUFF_TABLE, "Bogus Huffman table definition")
+JMESSAGE(JERR_BAD_IN_COLORSPACE, "Bogus input colorspace")
+JMESSAGE(JERR_BAD_J_COLORSPACE, "Bogus JPEG colorspace")
+JMESSAGE(JERR_BAD_LENGTH, "Bogus marker length")
+JMESSAGE(JERR_BAD_LIB_VERSION,
+ "Wrong JPEG library version: library is %d, caller expects %d")
+JMESSAGE(JERR_BAD_LOSSLESS,
+ "Invalid lossless parameters Ss=%d Se=%d Ah=%d Al=%d")
+JMESSAGE(JERR_BAD_LOSSLESS_SCRIPT,
+ "Invalid lossless parameters at scan script entry %d")
+JMESSAGE(JERR_BAD_MCU_SIZE, "Sampling factors too large for interleaved scan")
+JMESSAGE(JERR_BAD_POOL_ID, "Invalid memory pool code %d")
+JMESSAGE(JERR_BAD_PRECISION, "Unsupported JPEG data precision %d")
+JMESSAGE(JERR_BAD_PROGRESSION,
+ "Invalid progressive parameters Ss=%d Se=%d Ah=%d Al=%d")
+JMESSAGE(JERR_BAD_PROG_SCRIPT,
+ "Invalid progressive parameters at scan script entry %d")
+JMESSAGE(JERR_BAD_RESTART, "Invalid restart interval: %d, must be an integer multiple of the number of MCUs in an MCU_row (%d)")
+JMESSAGE(JERR_BAD_SAMPLING, "Bogus sampling factors")
+JMESSAGE(JERR_BAD_SCAN_SCRIPT, "Invalid scan script at entry %d")
+JMESSAGE(JERR_BAD_STATE, "Improper call to JPEG library in state %d")
+JMESSAGE(JERR_BAD_STRUCT_SIZE,
+ "JPEG parameter struct mismatch: library thinks size is %u, caller expects %u")
+JMESSAGE(JERR_BAD_VIRTUAL_ACCESS, "Bogus virtual array access")
+JMESSAGE(JERR_BUFFER_SIZE, "Buffer passed to JPEG library is too small")
+JMESSAGE(JERR_CANT_SUSPEND, "Suspension not allowed here")
+JMESSAGE(JERR_CANT_TRANSCODE,
+ "Cannot transcode to/from lossless JPEG datastreams")
+JMESSAGE(JERR_CCIR601_NOTIMPL, "CCIR601 sampling not implemented yet")
+JMESSAGE(JERR_COMPONENT_COUNT, "Too many color components: %d, max %d")
+JMESSAGE(JERR_CONVERSION_NOTIMPL, "Unsupported color conversion request")
+JMESSAGE(JERR_DAC_INDEX, "Bogus DAC index %d")
+JMESSAGE(JERR_DAC_VALUE, "Bogus DAC value 0x%x")
+JMESSAGE(JERR_DHT_INDEX, "Bogus DHT index %d")
+JMESSAGE(JERR_DQT_INDEX, "Bogus DQT index %d")
+JMESSAGE(JERR_EMPTY_IMAGE, "Empty JPEG image (DNL not supported)")
+JMESSAGE(JERR_EMS_READ, "Read from EMS failed")
+JMESSAGE(JERR_EMS_WRITE, "Write to EMS failed")
+JMESSAGE(JERR_EOI_EXPECTED, "Didn't expect more than one scan")
+JMESSAGE(JERR_FILE_READ, "Input file read error")
+JMESSAGE(JERR_FILE_WRITE, "Output file write error --- out of disk space?")
+JMESSAGE(JERR_FRACT_SAMPLE_NOTIMPL, "Fractional sampling not implemented yet")
+JMESSAGE(JERR_HUFF_CLEN_OVERFLOW, "Huffman code size table overflow")
+JMESSAGE(JERR_HUFF_MISSING_CODE, "Missing Huffman code table entry")
+JMESSAGE(JERR_IMAGE_TOO_BIG, "Maximum supported image dimension is %u pixels")
+JMESSAGE(JERR_INPUT_EMPTY, "Empty input file")
+JMESSAGE(JERR_INPUT_EOF, "Premature end of input file")
+JMESSAGE(JERR_MISMATCHED_QUANT_TABLE,
+ "Cannot transcode due to multiple use of quantization table %d")
+JMESSAGE(JERR_MISSING_DATA, "Scan script does not transmit all data")
+JMESSAGE(JERR_MODE_CHANGE, "Invalid color quantization mode change")
+JMESSAGE(JERR_NOTIMPL, "Not implemented yet")
+JMESSAGE(JERR_NOT_COMPILED, "Requested feature was omitted at compile time")
+JMESSAGE(JERR_NO_ARITH_TABLE, "Arithmetic table 0x%02x was not defined")
+JMESSAGE(JERR_NO_BACKING_STORE, "Backing store not supported")
+JMESSAGE(JERR_NO_HUFF_TABLE, "Huffman table 0x%02x was not defined")
+JMESSAGE(JERR_NO_IMAGE, "JPEG datastream contains no image")
+JMESSAGE(JERR_NO_LOSSLESS_SCRIPT, "Lossless encoding was requested but no scan script was supplied")
+JMESSAGE(JERR_NO_QUANT_TABLE, "Quantization table 0x%02x was not defined")
+JMESSAGE(JERR_NO_SOI, "Not a JPEG file: starts with 0x%02x 0x%02x")
+JMESSAGE(JERR_OUT_OF_MEMORY, "Insufficient memory (case %d)")
+JMESSAGE(JERR_QUANT_COMPONENTS,
+ "Cannot quantize more than %d color components")
+JMESSAGE(JERR_QUANT_FEW_COLORS, "Cannot quantize to fewer than %d colors")
+JMESSAGE(JERR_QUANT_MANY_COLORS, "Cannot quantize to more than %d colors")
+JMESSAGE(JERR_SOF_DUPLICATE, "Invalid JPEG file structure: two SOF markers")
+JMESSAGE(JERR_SOF_NO_SOS, "Invalid JPEG file structure: missing SOS marker")
+JMESSAGE(JERR_SOF_UNSUPPORTED, "Unsupported JPEG process: SOF type 0x%02x")
+JMESSAGE(JERR_SOI_DUPLICATE, "Invalid JPEG file structure: two SOI markers")
+JMESSAGE(JERR_SOS_NO_SOF, "Invalid JPEG file structure: SOS before SOF")
+JMESSAGE(JERR_TFILE_CREATE, "Failed to create temporary file %s")
+JMESSAGE(JERR_TFILE_READ, "Read failed on temporary file")
+JMESSAGE(JERR_TFILE_SEEK, "Seek failed on temporary file")
+JMESSAGE(JERR_TFILE_WRITE,
+ "Write failed on temporary file --- out of disk space?")
+JMESSAGE(JERR_TOO_LITTLE_DATA, "Application transferred too few scanlines")
+JMESSAGE(JERR_UNKNOWN_MARKER, "Unsupported marker type 0x%02x")
+JMESSAGE(JERR_VIRTUAL_BUG, "Virtual array controller messed up")
+JMESSAGE(JERR_WIDTH_OVERFLOW, "Image too wide for this implementation")
+JMESSAGE(JERR_XMS_READ, "Read from XMS failed")
+JMESSAGE(JERR_XMS_WRITE, "Write to XMS failed")
+JMESSAGE(JMSG_COPYRIGHT, JCOPYRIGHT)
+JMESSAGE(JMSG_VERSION, JVERSION)
+JMESSAGE(JTRC_16BIT_TABLES,
+ "Caution: quantization tables are too coarse for baseline JPEG")
+JMESSAGE(JTRC_ADOBE,
+ "Adobe APP14 marker: version %d, flags 0x%04x 0x%04x, transform %d")
+JMESSAGE(JTRC_APP0, "Unknown APP0 marker (not JFIF), length %u")
+JMESSAGE(JTRC_APP14, "Unknown APP14 marker (not Adobe), length %u")
+JMESSAGE(JTRC_DAC, "Define Arithmetic Table 0x%02x: 0x%02x")
+JMESSAGE(JTRC_DHT, "Define Huffman Table 0x%02x")
+JMESSAGE(JTRC_DQT, "Define Quantization Table %d precision %d")
+JMESSAGE(JTRC_DRI, "Define Restart Interval %u")
+JMESSAGE(JTRC_EMS_CLOSE, "Freed EMS handle %u")
+JMESSAGE(JTRC_EMS_OPEN, "Obtained EMS handle %u")
+JMESSAGE(JTRC_EOI, "End Of Image")
+JMESSAGE(JTRC_HUFFBITS, " %3d %3d %3d %3d %3d %3d %3d %3d")
+JMESSAGE(JTRC_JFIF, "JFIF APP0 marker: version %d.%02d, density %dx%d %d")
+JMESSAGE(JTRC_JFIF_BADTHUMBNAILSIZE,
+ "Warning: thumbnail image size does not match data length %u")
+JMESSAGE(JTRC_JFIF_EXTENSION,
+ "JFIF extension marker: type 0x%02x, length %u")
+JMESSAGE(JTRC_JFIF_THUMBNAIL, " with %d x %d thumbnail image")
+JMESSAGE(JTRC_MISC_MARKER, "Miscellaneous marker 0x%02x, length %u")
+JMESSAGE(JTRC_PARMLESS_MARKER, "Unexpected marker 0x%02x")
+JMESSAGE(JTRC_QUANTVALS, " %4u %4u %4u %4u %4u %4u %4u %4u")
+JMESSAGE(JTRC_QUANT_3_NCOLORS, "Quantizing to %d = %d*%d*%d colors")
+JMESSAGE(JTRC_QUANT_NCOLORS, "Quantizing to %d colors")
+JMESSAGE(JTRC_QUANT_SELECTED, "Selected %d colors for quantization")
+JMESSAGE(JTRC_RECOVERY_ACTION, "At marker 0x%02x, recovery action %d")
+JMESSAGE(JTRC_RST, "RST%d")
+JMESSAGE(JTRC_SMOOTH_NOTIMPL,
+ "Smoothing not supported with nonstandard sampling ratios")
+JMESSAGE(JTRC_SOF, "Start Of Frame 0x%02x: width=%u, height=%u, components=%d")
+JMESSAGE(JTRC_SOF_COMPONENT, " Component %d: %dhx%dv q=%d")
+JMESSAGE(JTRC_SOI, "Start of Image")
+JMESSAGE(JTRC_SOS, "Start Of Scan: %d components")
+JMESSAGE(JTRC_SOS_COMPONENT, " Component %d: dc=%d ac=%d")
+JMESSAGE(JTRC_SOS_PARAMS, " Ss=%d, Se=%d, Ah=%d, Al=%d")
+JMESSAGE(JTRC_TFILE_CLOSE, "Closed temporary file %s")
+JMESSAGE(JTRC_TFILE_OPEN, "Opened temporary file %s")
+JMESSAGE(JTRC_THUMB_JPEG,
+ "JFIF extension marker: JPEG-compressed thumbnail image, length %u")
+JMESSAGE(JTRC_THUMB_PALETTE,
+ "JFIF extension marker: palette thumbnail image, length %u")
+JMESSAGE(JTRC_THUMB_RGB,
+ "JFIF extension marker: RGB thumbnail image, length %u")
+JMESSAGE(JTRC_UNKNOWN_LOSSLESS_IDS,
+ "Unrecognized component IDs %d %d %d, assuming RGB")
+JMESSAGE(JTRC_UNKNOWN_LOSSY_IDS,
+ "Unrecognized component IDs %d %d %d, assuming YCbCr")
+JMESSAGE(JTRC_XMS_CLOSE, "Freed XMS handle %u")
+JMESSAGE(JTRC_XMS_OPEN, "Obtained XMS handle %u")
+JMESSAGE(JWRN_ADOBE_XFORM, "Unknown Adobe color transform code %d")
+JMESSAGE(JWRN_ARITH_BAD_CODE, "Corrupt JPEG data: bad arithmetic code")
+JMESSAGE(JWRN_BOGUS_PROGRESSION,
+ "Inconsistent progression sequence for component %d coefficient %d")
+JMESSAGE(JWRN_EXTRANEOUS_DATA,
+ "Corrupt JPEG data: %u extraneous bytes before marker 0x%02x")
+JMESSAGE(JWRN_HIT_MARKER, "Corrupt JPEG data: premature end of data segment")
+JMESSAGE(JWRN_HUFF_BAD_CODE, "Corrupt JPEG data: bad Huffman code")
+JMESSAGE(JWRN_JFIF_MAJOR, "Warning: unknown JFIF revision number %d.%02d")
+JMESSAGE(JWRN_JPEG_EOF, "Premature end of JPEG file")
+JMESSAGE(JWRN_MUST_DOWNSCALE,
+ "Must downscale data from %d bits to %d")
+JMESSAGE(JWRN_MUST_RESYNC,
+ "Corrupt JPEG data: found marker 0x%02x instead of RST%d")
+JMESSAGE(JWRN_NOT_SEQUENTIAL, "Invalid SOS parameters for sequential JPEG")
+JMESSAGE(JWRN_TOO_MUCH_DATA, "Application transferred too many scanlines")
+
+#ifdef JMAKE_ENUM_LIST
+
+ JMSG_LASTMSGCODE
+} J_MESSAGE_CODE;
+
+#undef JMAKE_ENUM_LIST
+#endif /* JMAKE_ENUM_LIST */
+
+/* Zap JMESSAGE macro so that future re-inclusions do nothing by default */
+#undef JMESSAGE
+
+
+#ifndef JERROR_H
+#define JERROR_H
+
+/* Macros to simplify using the error and trace message stuff */
+/* The first parameter is either type of cinfo pointer */
+
+/* Fatal errors (print message and exit) */
+#define ERREXIT(cinfo,code) \
+ ((cinfo)->err->msg_code = (code), \
+ (*(cinfo)->err->error_exit) ((j_common_ptr) (cinfo)))
+#define ERREXIT1(cinfo,code,p1) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (*(cinfo)->err->error_exit) ((j_common_ptr) (cinfo)))
+#define ERREXIT2(cinfo,code,p1,p2) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (cinfo)->err->msg_parm.i[1] = (p2), \
+ (*(cinfo)->err->error_exit) ((j_common_ptr) (cinfo)))
+#define ERREXIT3(cinfo,code,p1,p2,p3) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (cinfo)->err->msg_parm.i[1] = (p2), \
+ (cinfo)->err->msg_parm.i[2] = (p3), \
+ (*(cinfo)->err->error_exit) ((j_common_ptr) (cinfo)))
+#define ERREXIT4(cinfo,code,p1,p2,p3,p4) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (cinfo)->err->msg_parm.i[1] = (p2), \
+ (cinfo)->err->msg_parm.i[2] = (p3), \
+ (cinfo)->err->msg_parm.i[3] = (p4), \
+ (*(cinfo)->err->error_exit) ((j_common_ptr) (cinfo)))
+#define ERREXITS(cinfo,code,str) \
+ ((cinfo)->err->msg_code = (code), \
+ strncpy((cinfo)->err->msg_parm.s, (str), JMSG_STR_PARM_MAX), \
+ (*(cinfo)->err->error_exit) ((j_common_ptr) (cinfo)))
+
+#define MAKESTMT(stuff) do { stuff } while (0)
+
+/* Nonfatal errors (we can keep going, but the data is probably corrupt) */
+#define WARNMS(cinfo,code) \
+ ((cinfo)->err->msg_code = (code), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), -1))
+#define WARNMS1(cinfo,code,p1) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), -1))
+#define WARNMS2(cinfo,code,p1,p2) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (cinfo)->err->msg_parm.i[1] = (p2), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), -1))
+
+/* Informational/debugging messages */
+#define TRACEMS(cinfo,lvl,code) \
+ ((cinfo)->err->msg_code = (code), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)))
+#define TRACEMS1(cinfo,lvl,code,p1) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)))
+#define TRACEMS2(cinfo,lvl,code,p1,p2) \
+ ((cinfo)->err->msg_code = (code), \
+ (cinfo)->err->msg_parm.i[0] = (p1), \
+ (cinfo)->err->msg_parm.i[1] = (p2), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)))
+#define TRACEMS3(cinfo,lvl,code,p1,p2,p3) \
+ MAKESTMT(int * _mp = (cinfo)->err->msg_parm.i; \
+ _mp[0] = (p1); _mp[1] = (p2); _mp[2] = (p3); \
+ (cinfo)->err->msg_code = (code); \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)); )
+#define TRACEMS4(cinfo,lvl,code,p1,p2,p3,p4) \
+ MAKESTMT(int * _mp = (cinfo)->err->msg_parm.i; \
+ _mp[0] = (p1); _mp[1] = (p2); _mp[2] = (p3); _mp[3] = (p4); \
+ (cinfo)->err->msg_code = (code); \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)); )
+#define TRACEMS5(cinfo,lvl,code,p1,p2,p3,p4,p5) \
+ MAKESTMT(int * _mp = (cinfo)->err->msg_parm.i; \
+ _mp[0] = (p1); _mp[1] = (p2); _mp[2] = (p3); _mp[3] = (p4); \
+ _mp[4] = (p5); \
+ (cinfo)->err->msg_code = (code); \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)); )
+#define TRACEMS8(cinfo,lvl,code,p1,p2,p3,p4,p5,p6,p7,p8) \
+ MAKESTMT(int * _mp = (cinfo)->err->msg_parm.i; \
+ _mp[0] = (p1); _mp[1] = (p2); _mp[2] = (p3); _mp[3] = (p4); \
+ _mp[4] = (p5); _mp[5] = (p6); _mp[6] = (p7); _mp[7] = (p8); \
+ (cinfo)->err->msg_code = (code); \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)); )
+#define TRACEMSS(cinfo,lvl,code,str) \
+ ((cinfo)->err->msg_code = (code), \
+ strncpy((cinfo)->err->msg_parm.s, (str), JMSG_STR_PARM_MAX), \
+ (*(cinfo)->err->emit_message) ((j_common_ptr) (cinfo), (lvl)))
+
+#endif /* JERROR_H */
--- /dev/null
+/*
+ * jfdctflt.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains a floating-point implementation of the
+ * forward DCT (Discrete Cosine Transform).
+ *
+ * This implementation should be more accurate than either of the integer
+ * DCT implementations. However, it may not give the same results on all
+ * machines because of differences in roundoff behavior. Speed will depend
+ * on the hardware's floating point capacity.
+ *
+ * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
+ * on each column. Direct algorithms are also available, but they are
+ * much more complex and seem not to be any faster when reduced to code.
+ *
+ * This implementation is based on Arai, Agui, and Nakajima's algorithm for
+ * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
+ * Japanese, but the algorithm is described in the Pennebaker & Mitchell
+ * JPEG textbook (see REFERENCES section in file README). The following code
+ * is based directly on figure 4-8 in P&M.
+ * While an 8-point DCT cannot be done in less than 11 multiplies, it is
+ * possible to arrange the computation so that many of the multiplies are
+ * simple scalings of the final outputs. These multiplies can then be
+ * folded into the multiplications or divisions by the JPEG quantization
+ * table entries. The AA&N method leaves only 5 multiplies and 29 adds
+ * to be done in the DCT itself.
+ * The primary disadvantage of this method is that with a fixed-point
+ * implementation, accuracy is lost due to imprecise representation of the
+ * scaled quantization values. However, that problem does not arise if
+ * we use floating point arithmetic.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef DCT_FLOAT_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/*
+ * Perform the forward DCT on one block of samples.
+ */
+
+GLOBAL(void)
+jpeg_fdct_float (FAST_FLOAT * data)
+{
+ FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ FAST_FLOAT tmp10, tmp11, tmp12, tmp13;
+ FAST_FLOAT z1, z2, z3, z4, z5, z11, z13;
+ FAST_FLOAT *dataptr;
+ int ctr;
+
+ /* Pass 1: process rows. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[0] + dataptr[7];
+ tmp7 = dataptr[0] - dataptr[7];
+ tmp1 = dataptr[1] + dataptr[6];
+ tmp6 = dataptr[1] - dataptr[6];
+ tmp2 = dataptr[2] + dataptr[5];
+ tmp5 = dataptr[2] - dataptr[5];
+ tmp3 = dataptr[3] + dataptr[4];
+ tmp4 = dataptr[3] - dataptr[4];
+
+ /* Even part */
+
+ tmp10 = tmp0 + tmp3; /* phase 2 */
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[0] = tmp10 + tmp11; /* phase 3 */
+ dataptr[4] = tmp10 - tmp11;
+
+ z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */
+ dataptr[2] = tmp13 + z1; /* phase 5 */
+ dataptr[6] = tmp13 - z1;
+
+ /* Odd part */
+
+ tmp10 = tmp4 + tmp5; /* phase 2 */
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp6 + tmp7;
+
+ /* The rotator is modified from fig 4-8 to avoid extra negations. */
+ z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */
+ z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */
+ z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */
+ z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */
+
+ z11 = tmp7 + z3; /* phase 5 */
+ z13 = tmp7 - z3;
+
+ dataptr[5] = z13 + z2; /* phase 6 */
+ dataptr[3] = z13 - z2;
+ dataptr[1] = z11 + z4;
+ dataptr[7] = z11 - z4;
+
+ dataptr += DCTSIZE; /* advance pointer to next row */
+ }
+
+ /* Pass 2: process columns. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
+ tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
+ tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
+ tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
+ tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
+ tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
+ tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
+ tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
+
+ /* Even part */
+
+ tmp10 = tmp0 + tmp3; /* phase 2 */
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
+ dataptr[DCTSIZE*4] = tmp10 - tmp11;
+
+ z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */
+ dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
+ dataptr[DCTSIZE*6] = tmp13 - z1;
+
+ /* Odd part */
+
+ tmp10 = tmp4 + tmp5; /* phase 2 */
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp6 + tmp7;
+
+ /* The rotator is modified from fig 4-8 to avoid extra negations. */
+ z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */
+ z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */
+ z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */
+ z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */
+
+ z11 = tmp7 + z3; /* phase 5 */
+ z13 = tmp7 - z3;
+
+ dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
+ dataptr[DCTSIZE*3] = z13 - z2;
+ dataptr[DCTSIZE*1] = z11 + z4;
+ dataptr[DCTSIZE*7] = z11 - z4;
+
+ dataptr++; /* advance pointer to next column */
+ }
+}
+
+#endif /* DCT_FLOAT_SUPPORTED */
--- /dev/null
+/*
+ * jfdctfst.c
+ *
+ * Copyright (C) 1994-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains a fast, not so accurate integer implementation of the
+ * forward DCT (Discrete Cosine Transform).
+ *
+ * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
+ * on each column. Direct algorithms are also available, but they are
+ * much more complex and seem not to be any faster when reduced to code.
+ *
+ * This implementation is based on Arai, Agui, and Nakajima's algorithm for
+ * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
+ * Japanese, but the algorithm is described in the Pennebaker & Mitchell
+ * JPEG textbook (see REFERENCES section in file README). The following code
+ * is based directly on figure 4-8 in P&M.
+ * While an 8-point DCT cannot be done in less than 11 multiplies, it is
+ * possible to arrange the computation so that many of the multiplies are
+ * simple scalings of the final outputs. These multiplies can then be
+ * folded into the multiplications or divisions by the JPEG quantization
+ * table entries. The AA&N method leaves only 5 multiplies and 29 adds
+ * to be done in the DCT itself.
+ * The primary disadvantage of this method is that with fixed-point math,
+ * accuracy is lost due to imprecise representation of the scaled
+ * quantization values. The smaller the quantization table entry, the less
+ * precise the scaled value, so this implementation does worse with high-
+ * quality-setting files than with low-quality ones.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef DCT_IFAST_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/* Scaling decisions are generally the same as in the LL&M algorithm;
+ * see jfdctint.c for more details. However, we choose to descale
+ * (right shift) multiplication products as soon as they are formed,
+ * rather than carrying additional fractional bits into subsequent additions.
+ * This compromises accuracy slightly, but it lets us save a few shifts.
+ * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
+ * everywhere except in the multiplications proper; this saves a good deal
+ * of work on 16-bit-int machines.
+ *
+ * Again to save a few shifts, the intermediate results between pass 1 and
+ * pass 2 are not upscaled, but are represented only to integral precision.
+ *
+ * A final compromise is to represent the multiplicative constants to only
+ * 8 fractional bits, rather than 13. This saves some shifting work on some
+ * machines, and may also reduce the cost of multiplication (since there
+ * are fewer one-bits in the constants).
+ */
+
+#define CONST_BITS 8
+
+
+/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
+ * causing a lot of useless floating-point operations at run time.
+ * To get around this we use the following pre-calculated constants.
+ * If you change CONST_BITS you may want to add appropriate values.
+ * (With a reasonable C compiler, you can just rely on the FIX() macro...)
+ */
+
+#if CONST_BITS == 8
+#define FIX_0_382683433 ((INT32) 98) /* FIX(0.382683433) */
+#define FIX_0_541196100 ((INT32) 139) /* FIX(0.541196100) */
+#define FIX_0_707106781 ((INT32) 181) /* FIX(0.707106781) */
+#define FIX_1_306562965 ((INT32) 334) /* FIX(1.306562965) */
+#else
+#define FIX_0_382683433 FIX(0.382683433)
+#define FIX_0_541196100 FIX(0.541196100)
+#define FIX_0_707106781 FIX(0.707106781)
+#define FIX_1_306562965 FIX(1.306562965)
+#endif
+
+
+/* We can gain a little more speed, with a further compromise in accuracy,
+ * by omitting the addition in a descaling shift. This yields an incorrectly
+ * rounded result half the time...
+ */
+
+#ifndef USE_ACCURATE_ROUNDING
+#undef DESCALE
+#define DESCALE(x,n) RIGHT_SHIFT(x, n)
+#endif
+
+
+/* Multiply a DCTELEM variable by an INT32 constant, and immediately
+ * descale to yield a DCTELEM result.
+ */
+
+#define MULTIPLY(var,const) ((DCTELEM) DESCALE((var) * (const), CONST_BITS))
+
+
+/*
+ * Perform the forward DCT on one block of samples.
+ */
+
+GLOBAL(void)
+jpeg_fdct_ifast (DCTELEM * data)
+{
+ DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ DCTELEM tmp10, tmp11, tmp12, tmp13;
+ DCTELEM z1, z2, z3, z4, z5, z11, z13;
+ DCTELEM *dataptr;
+ int ctr;
+ SHIFT_TEMPS
+
+ /* Pass 1: process rows. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[0] + dataptr[7];
+ tmp7 = dataptr[0] - dataptr[7];
+ tmp1 = dataptr[1] + dataptr[6];
+ tmp6 = dataptr[1] - dataptr[6];
+ tmp2 = dataptr[2] + dataptr[5];
+ tmp5 = dataptr[2] - dataptr[5];
+ tmp3 = dataptr[3] + dataptr[4];
+ tmp4 = dataptr[3] - dataptr[4];
+
+ /* Even part */
+
+ tmp10 = tmp0 + tmp3; /* phase 2 */
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[0] = tmp10 + tmp11; /* phase 3 */
+ dataptr[4] = tmp10 - tmp11;
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
+ dataptr[2] = tmp13 + z1; /* phase 5 */
+ dataptr[6] = tmp13 - z1;
+
+ /* Odd part */
+
+ tmp10 = tmp4 + tmp5; /* phase 2 */
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp6 + tmp7;
+
+ /* The rotator is modified from fig 4-8 to avoid extra negations. */
+ z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
+ z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
+ z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
+ z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
+
+ z11 = tmp7 + z3; /* phase 5 */
+ z13 = tmp7 - z3;
+
+ dataptr[5] = z13 + z2; /* phase 6 */
+ dataptr[3] = z13 - z2;
+ dataptr[1] = z11 + z4;
+ dataptr[7] = z11 - z4;
+
+ dataptr += DCTSIZE; /* advance pointer to next row */
+ }
+
+ /* Pass 2: process columns. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
+ tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
+ tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
+ tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
+ tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
+ tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
+ tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
+ tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
+
+ /* Even part */
+
+ tmp10 = tmp0 + tmp3; /* phase 2 */
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
+ dataptr[DCTSIZE*4] = tmp10 - tmp11;
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
+ dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
+ dataptr[DCTSIZE*6] = tmp13 - z1;
+
+ /* Odd part */
+
+ tmp10 = tmp4 + tmp5; /* phase 2 */
+ tmp11 = tmp5 + tmp6;
+ tmp12 = tmp6 + tmp7;
+
+ /* The rotator is modified from fig 4-8 to avoid extra negations. */
+ z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
+ z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
+ z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
+ z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
+
+ z11 = tmp7 + z3; /* phase 5 */
+ z13 = tmp7 - z3;
+
+ dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
+ dataptr[DCTSIZE*3] = z13 - z2;
+ dataptr[DCTSIZE*1] = z11 + z4;
+ dataptr[DCTSIZE*7] = z11 - z4;
+
+ dataptr++; /* advance pointer to next column */
+ }
+}
+
+#endif /* DCT_IFAST_SUPPORTED */
--- /dev/null
+/*
+ * jfdctint.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains a slow-but-accurate integer implementation of the
+ * forward DCT (Discrete Cosine Transform).
+ *
+ * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
+ * on each column. Direct algorithms are also available, but they are
+ * much more complex and seem not to be any faster when reduced to code.
+ *
+ * This implementation is based on an algorithm described in
+ * C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
+ * Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
+ * Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
+ * The primary algorithm described there uses 11 multiplies and 29 adds.
+ * We use their alternate method with 12 multiplies and 32 adds.
+ * The advantage of this method is that no data path contains more than one
+ * multiplication; this allows a very simple and accurate implementation in
+ * scaled fixed-point arithmetic, with a minimal number of shifts.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef DCT_ISLOW_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/*
+ * The poop on this scaling stuff is as follows:
+ *
+ * Each 1-D DCT step produces outputs which are a factor of sqrt(N)
+ * larger than the true DCT outputs. The final outputs are therefore
+ * a factor of N larger than desired; since N=8 this can be cured by
+ * a simple right shift at the end of the algorithm. The advantage of
+ * this arrangement is that we save two multiplications per 1-D DCT,
+ * because the y0 and y4 outputs need not be divided by sqrt(N).
+ * In the IJG code, this factor of 8 is removed by the quantization step
+ * (in jcdctmgr.c), NOT in this module.
+ *
+ * We have to do addition and subtraction of the integer inputs, which
+ * is no problem, and multiplication by fractional constants, which is
+ * a problem to do in integer arithmetic. We multiply all the constants
+ * by CONST_SCALE and convert them to integer constants (thus retaining
+ * CONST_BITS bits of precision in the constants). After doing a
+ * multiplication we have to divide the product by CONST_SCALE, with proper
+ * rounding, to produce the correct output. This division can be done
+ * cheaply as a right shift of CONST_BITS bits. We postpone shifting
+ * as long as possible so that partial sums can be added together with
+ * full fractional precision.
+ *
+ * The outputs of the first pass are scaled up by PASS1_BITS bits so that
+ * they are represented to better-than-integral precision. These outputs
+ * require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word
+ * with the recommended scaling. (For 12-bit sample data, the intermediate
+ * array is INT32 anyway.)
+ *
+ * To avoid overflow of the 32-bit intermediate results in pass 2, we must
+ * have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis
+ * shows that the values given below are the most effective.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define CONST_BITS 13
+#define PASS1_BITS 2
+#else
+#define CONST_BITS 13
+#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
+#endif
+
+/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
+ * causing a lot of useless floating-point operations at run time.
+ * To get around this we use the following pre-calculated constants.
+ * If you change CONST_BITS you may want to add appropriate values.
+ * (With a reasonable C compiler, you can just rely on the FIX() macro...)
+ */
+
+#if CONST_BITS == 13
+#define FIX_0_298631336 ((INT32) 2446) /* FIX(0.298631336) */
+#define FIX_0_390180644 ((INT32) 3196) /* FIX(0.390180644) */
+#define FIX_0_541196100 ((INT32) 4433) /* FIX(0.541196100) */
+#define FIX_0_765366865 ((INT32) 6270) /* FIX(0.765366865) */
+#define FIX_0_899976223 ((INT32) 7373) /* FIX(0.899976223) */
+#define FIX_1_175875602 ((INT32) 9633) /* FIX(1.175875602) */
+#define FIX_1_501321110 ((INT32) 12299) /* FIX(1.501321110) */
+#define FIX_1_847759065 ((INT32) 15137) /* FIX(1.847759065) */
+#define FIX_1_961570560 ((INT32) 16069) /* FIX(1.961570560) */
+#define FIX_2_053119869 ((INT32) 16819) /* FIX(2.053119869) */
+#define FIX_2_562915447 ((INT32) 20995) /* FIX(2.562915447) */
+#define FIX_3_072711026 ((INT32) 25172) /* FIX(3.072711026) */
+#else
+#define FIX_0_298631336 FIX(0.298631336)
+#define FIX_0_390180644 FIX(0.390180644)
+#define FIX_0_541196100 FIX(0.541196100)
+#define FIX_0_765366865 FIX(0.765366865)
+#define FIX_0_899976223 FIX(0.899976223)
+#define FIX_1_175875602 FIX(1.175875602)
+#define FIX_1_501321110 FIX(1.501321110)
+#define FIX_1_847759065 FIX(1.847759065)
+#define FIX_1_961570560 FIX(1.961570560)
+#define FIX_2_053119869 FIX(2.053119869)
+#define FIX_2_562915447 FIX(2.562915447)
+#define FIX_3_072711026 FIX(3.072711026)
+#endif
+
+
+/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
+ * For 8-bit samples with the recommended scaling, all the variable
+ * and constant values involved are no more than 16 bits wide, so a
+ * 16x16->32 bit multiply can be used instead of a full 32x32 multiply.
+ * For 12-bit samples, a full 32-bit multiplication will be needed.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define MULTIPLY(var,const) MULTIPLY16C16(var,const)
+#else
+#define MULTIPLY(var,const) ((var) * (const))
+#endif
+
+
+/*
+ * Perform the forward DCT on one block of samples.
+ */
+
+GLOBAL(void)
+jpeg_fdct_islow (DCTELEM * data)
+{
+ INT32 tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ INT32 tmp10, tmp11, tmp12, tmp13;
+ INT32 z1, z2, z3, z4, z5;
+ DCTELEM *dataptr;
+ int ctr;
+ SHIFT_TEMPS
+
+ /* Pass 1: process rows. */
+ /* Note results are scaled up by sqrt(8) compared to a true DCT; */
+ /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[0] + dataptr[7];
+ tmp7 = dataptr[0] - dataptr[7];
+ tmp1 = dataptr[1] + dataptr[6];
+ tmp6 = dataptr[1] - dataptr[6];
+ tmp2 = dataptr[2] + dataptr[5];
+ tmp5 = dataptr[2] - dataptr[5];
+ tmp3 = dataptr[3] + dataptr[4];
+ tmp4 = dataptr[3] - dataptr[4];
+
+ /* Even part per LL&M figure 1 --- note that published figure is faulty;
+ * rotator "sqrt(2)*c1" should be "sqrt(2)*c6".
+ */
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[0] = (DCTELEM) ((tmp10 + tmp11) << PASS1_BITS);
+ dataptr[4] = (DCTELEM) ((tmp10 - tmp11) << PASS1_BITS);
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);
+ dataptr[2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),
+ CONST_BITS-PASS1_BITS);
+ dataptr[6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065),
+ CONST_BITS-PASS1_BITS);
+
+ /* Odd part per figure 8 --- note paper omits factor of sqrt(2).
+ * cK represents cos(K*pi/16).
+ * i0..i3 in the paper are tmp4..tmp7 here.
+ */
+
+ z1 = tmp4 + tmp7;
+ z2 = tmp5 + tmp6;
+ z3 = tmp4 + tmp6;
+ z4 = tmp5 + tmp7;
+ z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
+
+ tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ dataptr[7] = (DCTELEM) DESCALE(tmp4 + z1 + z3, CONST_BITS-PASS1_BITS);
+ dataptr[5] = (DCTELEM) DESCALE(tmp5 + z2 + z4, CONST_BITS-PASS1_BITS);
+ dataptr[3] = (DCTELEM) DESCALE(tmp6 + z2 + z3, CONST_BITS-PASS1_BITS);
+ dataptr[1] = (DCTELEM) DESCALE(tmp7 + z1 + z4, CONST_BITS-PASS1_BITS);
+
+ dataptr += DCTSIZE; /* advance pointer to next row */
+ }
+
+ /* Pass 2: process columns.
+ * We remove the PASS1_BITS scaling, but leave the results scaled up
+ * by an overall factor of 8.
+ */
+
+ dataptr = data;
+ for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
+ tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
+ tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
+ tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
+ tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
+ tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
+ tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
+ tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
+ tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
+
+ /* Even part per LL&M figure 1 --- note that published figure is faulty;
+ * rotator "sqrt(2)*c1" should be "sqrt(2)*c6".
+ */
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp11, PASS1_BITS);
+ dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp10 - tmp11, PASS1_BITS);
+
+ z1 = MULTIPLY(tmp12 + tmp13, FIX_0_541196100);
+ dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp13, FIX_0_765366865),
+ CONST_BITS+PASS1_BITS);
+ dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(z1 + MULTIPLY(tmp12, - FIX_1_847759065),
+ CONST_BITS+PASS1_BITS);
+
+ /* Odd part per figure 8 --- note paper omits factor of sqrt(2).
+ * cK represents cos(K*pi/16).
+ * i0..i3 in the paper are tmp4..tmp7 here.
+ */
+
+ z1 = tmp4 + tmp7;
+ z2 = tmp5 + tmp6;
+ z3 = tmp4 + tmp6;
+ z4 = tmp5 + tmp7;
+ z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
+
+ tmp4 = MULTIPLY(tmp4, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp5 = MULTIPLY(tmp5, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp6 = MULTIPLY(tmp6, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp7 = MULTIPLY(tmp7, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp4 + z1 + z3,
+ CONST_BITS+PASS1_BITS);
+ dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp5 + z2 + z4,
+ CONST_BITS+PASS1_BITS);
+ dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp6 + z2 + z3,
+ CONST_BITS+PASS1_BITS);
+ dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp7 + z1 + z4,
+ CONST_BITS+PASS1_BITS);
+
+ dataptr++; /* advance pointer to next column */
+ }
+}
+
+#endif /* DCT_ISLOW_SUPPORTED */
--- /dev/null
+/*
+ * jidctflt.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains a floating-point implementation of the
+ * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
+ * must also perform dequantization of the input coefficients.
+ *
+ * This implementation should be more accurate than either of the integer
+ * IDCT implementations. However, it may not give the same results on all
+ * machines because of differences in roundoff behavior. Speed will depend
+ * on the hardware's floating point capacity.
+ *
+ * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
+ * on each row (or vice versa, but it's more convenient to emit a row at
+ * a time). Direct algorithms are also available, but they are much more
+ * complex and seem not to be any faster when reduced to code.
+ *
+ * This implementation is based on Arai, Agui, and Nakajima's algorithm for
+ * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
+ * Japanese, but the algorithm is described in the Pennebaker & Mitchell
+ * JPEG textbook (see REFERENCES section in file README). The following code
+ * is based directly on figure 4-8 in P&M.
+ * While an 8-point DCT cannot be done in less than 11 multiplies, it is
+ * possible to arrange the computation so that many of the multiplies are
+ * simple scalings of the final outputs. These multiplies can then be
+ * folded into the multiplications or divisions by the JPEG quantization
+ * table entries. The AA&N method leaves only 5 multiplies and 29 adds
+ * to be done in the DCT itself.
+ * The primary disadvantage of this method is that with a fixed-point
+ * implementation, accuracy is lost due to imprecise representation of the
+ * scaled quantization values. However, that problem does not arise if
+ * we use floating point arithmetic.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef DCT_FLOAT_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/* Dequantize a coefficient by multiplying it by the multiplier-table
+ * entry; produce a float result.
+ */
+
+#define DEQUANTIZE(coef,quantval) (((FAST_FLOAT) (coef)) * (quantval))
+
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients.
+ */
+
+GLOBAL(void)
+jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col)
+{
+ FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ FAST_FLOAT tmp10, tmp11, tmp12, tmp13;
+ FAST_FLOAT z5, z10, z11, z12, z13;
+ JCOEFPTR inptr;
+ FLOAT_MULT_TYPE * quantptr;
+ FAST_FLOAT * wsptr;
+ JSAMPROW outptr;
+ JSAMPLE *range_limit = IDCT_range_limit(cinfo);
+ int ctr;
+ FAST_FLOAT workspace[DCTSIZE2]; /* buffers data between passes */
+ SHIFT_TEMPS
+
+ /* Pass 1: process columns from input, store into work array. */
+
+ inptr = coef_block;
+ quantptr = (FLOAT_MULT_TYPE *) compptr->dct_table;
+ wsptr = workspace;
+ for (ctr = DCTSIZE; ctr > 0; ctr--) {
+ /* Due to quantization, we will usually find that many of the input
+ * coefficients are zero, especially the AC terms. We can exploit this
+ * by short-circuiting the IDCT calculation for any column in which all
+ * the AC terms are zero. In that case each output is equal to the
+ * DC coefficient (with scale factor as needed).
+ * With typical images and quantization tables, half or more of the
+ * column DCT calculations can be simplified this way.
+ */
+
+ if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 &&
+ inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 &&
+ inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 &&
+ inptr[DCTSIZE*7] == 0) {
+ /* AC terms all zero */
+ FAST_FLOAT dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+
+ wsptr[DCTSIZE*0] = dcval;
+ wsptr[DCTSIZE*1] = dcval;
+ wsptr[DCTSIZE*2] = dcval;
+ wsptr[DCTSIZE*3] = dcval;
+ wsptr[DCTSIZE*4] = dcval;
+ wsptr[DCTSIZE*5] = dcval;
+ wsptr[DCTSIZE*6] = dcval;
+ wsptr[DCTSIZE*7] = dcval;
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ continue;
+ }
+
+ /* Even part */
+
+ tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+ tmp1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
+ tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
+ tmp3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
+
+ tmp10 = tmp0 + tmp2; /* phase 3 */
+ tmp11 = tmp0 - tmp2;
+
+ tmp13 = tmp1 + tmp3; /* phases 5-3 */
+ tmp12 = (tmp1 - tmp3) * ((FAST_FLOAT) 1.414213562) - tmp13; /* 2*c4 */
+
+ tmp0 = tmp10 + tmp13; /* phase 2 */
+ tmp3 = tmp10 - tmp13;
+ tmp1 = tmp11 + tmp12;
+ tmp2 = tmp11 - tmp12;
+
+ /* Odd part */
+
+ tmp4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
+ tmp5 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
+ tmp6 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
+ tmp7 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
+
+ z13 = tmp6 + tmp5; /* phase 6 */
+ z10 = tmp6 - tmp5;
+ z11 = tmp4 + tmp7;
+ z12 = tmp4 - tmp7;
+
+ tmp7 = z11 + z13; /* phase 5 */
+ tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); /* 2*c4 */
+
+ z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */
+ tmp10 = ((FAST_FLOAT) 1.082392200) * z12 - z5; /* 2*(c2-c6) */
+ tmp12 = ((FAST_FLOAT) -2.613125930) * z10 + z5; /* -2*(c2+c6) */
+
+ tmp6 = tmp12 - tmp7; /* phase 2 */
+ tmp5 = tmp11 - tmp6;
+ tmp4 = tmp10 + tmp5;
+
+ wsptr[DCTSIZE*0] = tmp0 + tmp7;
+ wsptr[DCTSIZE*7] = tmp0 - tmp7;
+ wsptr[DCTSIZE*1] = tmp1 + tmp6;
+ wsptr[DCTSIZE*6] = tmp1 - tmp6;
+ wsptr[DCTSIZE*2] = tmp2 + tmp5;
+ wsptr[DCTSIZE*5] = tmp2 - tmp5;
+ wsptr[DCTSIZE*4] = tmp3 + tmp4;
+ wsptr[DCTSIZE*3] = tmp3 - tmp4;
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ }
+
+ /* Pass 2: process rows from work array, store into output array. */
+ /* Note that we must descale the results by a factor of 8 == 2**3. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < DCTSIZE; ctr++) {
+ outptr = output_buf[ctr] + output_col;
+ /* Rows of zeroes can be exploited in the same way as we did with columns.
+ * However, the column calculation has created many nonzero AC terms, so
+ * the simplification applies less often (typically 5% to 10% of the time).
+ * And testing floats for zero is relatively expensive, so we don't bother.
+ */
+
+ /* Even part */
+
+ tmp10 = wsptr[0] + wsptr[4];
+ tmp11 = wsptr[0] - wsptr[4];
+
+ tmp13 = wsptr[2] + wsptr[6];
+ tmp12 = (wsptr[2] - wsptr[6]) * ((FAST_FLOAT) 1.414213562) - tmp13;
+
+ tmp0 = tmp10 + tmp13;
+ tmp3 = tmp10 - tmp13;
+ tmp1 = tmp11 + tmp12;
+ tmp2 = tmp11 - tmp12;
+
+ /* Odd part */
+
+ z13 = wsptr[5] + wsptr[3];
+ z10 = wsptr[5] - wsptr[3];
+ z11 = wsptr[1] + wsptr[7];
+ z12 = wsptr[1] - wsptr[7];
+
+ tmp7 = z11 + z13;
+ tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562);
+
+ z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */
+ tmp10 = ((FAST_FLOAT) 1.082392200) * z12 - z5; /* 2*(c2-c6) */
+ tmp12 = ((FAST_FLOAT) -2.613125930) * z10 + z5; /* -2*(c2+c6) */
+
+ tmp6 = tmp12 - tmp7;
+ tmp5 = tmp11 - tmp6;
+ tmp4 = tmp10 + tmp5;
+
+ /* Final output stage: scale down by a factor of 8 and range-limit */
+
+ outptr[0] = range_limit[(int) DESCALE((INT32) (tmp0 + tmp7), 3)
+ & RANGE_MASK];
+ outptr[7] = range_limit[(int) DESCALE((INT32) (tmp0 - tmp7), 3)
+ & RANGE_MASK];
+ outptr[1] = range_limit[(int) DESCALE((INT32) (tmp1 + tmp6), 3)
+ & RANGE_MASK];
+ outptr[6] = range_limit[(int) DESCALE((INT32) (tmp1 - tmp6), 3)
+ & RANGE_MASK];
+ outptr[2] = range_limit[(int) DESCALE((INT32) (tmp2 + tmp5), 3)
+ & RANGE_MASK];
+ outptr[5] = range_limit[(int) DESCALE((INT32) (tmp2 - tmp5), 3)
+ & RANGE_MASK];
+ outptr[4] = range_limit[(int) DESCALE((INT32) (tmp3 + tmp4), 3)
+ & RANGE_MASK];
+ outptr[3] = range_limit[(int) DESCALE((INT32) (tmp3 - tmp4), 3)
+ & RANGE_MASK];
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ }
+}
+
+#endif /* DCT_FLOAT_SUPPORTED */
--- /dev/null
+/*
+ * jidctfst.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains a fast, not so accurate integer implementation of the
+ * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
+ * must also perform dequantization of the input coefficients.
+ *
+ * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
+ * on each row (or vice versa, but it's more convenient to emit a row at
+ * a time). Direct algorithms are also available, but they are much more
+ * complex and seem not to be any faster when reduced to code.
+ *
+ * This implementation is based on Arai, Agui, and Nakajima's algorithm for
+ * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
+ * Japanese, but the algorithm is described in the Pennebaker & Mitchell
+ * JPEG textbook (see REFERENCES section in file README). The following code
+ * is based directly on figure 4-8 in P&M.
+ * While an 8-point DCT cannot be done in less than 11 multiplies, it is
+ * possible to arrange the computation so that many of the multiplies are
+ * simple scalings of the final outputs. These multiplies can then be
+ * folded into the multiplications or divisions by the JPEG quantization
+ * table entries. The AA&N method leaves only 5 multiplies and 29 adds
+ * to be done in the DCT itself.
+ * The primary disadvantage of this method is that with fixed-point math,
+ * accuracy is lost due to imprecise representation of the scaled
+ * quantization values. The smaller the quantization table entry, the less
+ * precise the scaled value, so this implementation does worse with high-
+ * quality-setting files than with low-quality ones.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef DCT_IFAST_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/* Scaling decisions are generally the same as in the LL&M algorithm;
+ * see jidctint.c for more details. However, we choose to descale
+ * (right shift) multiplication products as soon as they are formed,
+ * rather than carrying additional fractional bits into subsequent additions.
+ * This compromises accuracy slightly, but it lets us save a few shifts.
+ * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
+ * everywhere except in the multiplications proper; this saves a good deal
+ * of work on 16-bit-int machines.
+ *
+ * The dequantized coefficients are not integers because the AA&N scaling
+ * factors have been incorporated. We represent them scaled up by PASS1_BITS,
+ * so that the first and second IDCT rounds have the same input scaling.
+ * For 8-bit JSAMPLEs, we choose IFAST_SCALE_BITS = PASS1_BITS so as to
+ * avoid a descaling shift; this compromises accuracy rather drastically
+ * for small quantization table entries, but it saves a lot of shifts.
+ * For 12-bit JSAMPLEs, there's no hope of using 16x16 multiplies anyway,
+ * so we use a much larger scaling factor to preserve accuracy.
+ *
+ * A final compromise is to represent the multiplicative constants to only
+ * 8 fractional bits, rather than 13. This saves some shifting work on some
+ * machines, and may also reduce the cost of multiplication (since there
+ * are fewer one-bits in the constants).
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define CONST_BITS 8
+#define PASS1_BITS 2
+#else
+#define CONST_BITS 8
+#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
+#endif
+
+/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
+ * causing a lot of useless floating-point operations at run time.
+ * To get around this we use the following pre-calculated constants.
+ * If you change CONST_BITS you may want to add appropriate values.
+ * (With a reasonable C compiler, you can just rely on the FIX() macro...)
+ */
+
+#if CONST_BITS == 8
+#define FIX_1_082392200 ((INT32) 277) /* FIX(1.082392200) */
+#define FIX_1_414213562 ((INT32) 362) /* FIX(1.414213562) */
+#define FIX_1_847759065 ((INT32) 473) /* FIX(1.847759065) */
+#define FIX_2_613125930 ((INT32) 669) /* FIX(2.613125930) */
+#else
+#define FIX_1_082392200 FIX(1.082392200)
+#define FIX_1_414213562 FIX(1.414213562)
+#define FIX_1_847759065 FIX(1.847759065)
+#define FIX_2_613125930 FIX(2.613125930)
+#endif
+
+
+/* We can gain a little more speed, with a further compromise in accuracy,
+ * by omitting the addition in a descaling shift. This yields an incorrectly
+ * rounded result half the time...
+ */
+
+#ifndef USE_ACCURATE_ROUNDING
+#undef DESCALE
+#define DESCALE(x,n) RIGHT_SHIFT(x, n)
+#endif
+
+
+/* Multiply a DCTELEM variable by an INT32 constant, and immediately
+ * descale to yield a DCTELEM result.
+ */
+
+#define MULTIPLY(var,const) ((DCTELEM) DESCALE((var) * (const), CONST_BITS))
+
+
+/* Dequantize a coefficient by multiplying it by the multiplier-table
+ * entry; produce a DCTELEM result. For 8-bit data a 16x16->16
+ * multiplication will do. For 12-bit data, the multiplier table is
+ * declared INT32, so a 32-bit multiply will be used.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define DEQUANTIZE(coef,quantval) (((IFAST_MULT_TYPE) (coef)) * (quantval))
+#else
+#define DEQUANTIZE(coef,quantval) \
+ DESCALE((coef)*(quantval), IFAST_SCALE_BITS-PASS1_BITS)
+#endif
+
+
+/* Like DESCALE, but applies to a DCTELEM and produces an int.
+ * We assume that int right shift is unsigned if INT32 right shift is.
+ */
+
+#ifdef RIGHT_SHIFT_IS_UNSIGNED
+#define ISHIFT_TEMPS DCTELEM ishift_temp;
+#if BITS_IN_JSAMPLE == 8
+#define DCTELEMBITS 16 /* DCTELEM may be 16 or 32 bits */
+#else
+#define DCTELEMBITS 32 /* DCTELEM must be 32 bits */
+#endif
+#define IRIGHT_SHIFT(x,shft) \
+ ((ishift_temp = (x)) < 0 ? \
+ (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \
+ (ishift_temp >> (shft)))
+#else
+#define ISHIFT_TEMPS
+#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
+#endif
+
+#ifdef USE_ACCURATE_ROUNDING
+#define IDESCALE(x,n) ((int) IRIGHT_SHIFT((x) + (1 << ((n)-1)), n))
+#else
+#define IDESCALE(x,n) ((int) IRIGHT_SHIFT(x, n))
+#endif
+
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients.
+ */
+
+GLOBAL(void)
+jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col)
+{
+ DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+ DCTELEM tmp10, tmp11, tmp12, tmp13;
+ DCTELEM z5, z10, z11, z12, z13;
+ JCOEFPTR inptr;
+ IFAST_MULT_TYPE * quantptr;
+ int * wsptr;
+ JSAMPROW outptr;
+ JSAMPLE *range_limit = IDCT_range_limit(cinfo);
+ int ctr;
+ int workspace[DCTSIZE2]; /* buffers data between passes */
+ SHIFT_TEMPS /* for DESCALE */
+ ISHIFT_TEMPS /* for IDESCALE */
+
+ /* Pass 1: process columns from input, store into work array. */
+
+ inptr = coef_block;
+ quantptr = (IFAST_MULT_TYPE *) compptr->dct_table;
+ wsptr = workspace;
+ for (ctr = DCTSIZE; ctr > 0; ctr--) {
+ /* Due to quantization, we will usually find that many of the input
+ * coefficients are zero, especially the AC terms. We can exploit this
+ * by short-circuiting the IDCT calculation for any column in which all
+ * the AC terms are zero. In that case each output is equal to the
+ * DC coefficient (with scale factor as needed).
+ * With typical images and quantization tables, half or more of the
+ * column DCT calculations can be simplified this way.
+ */
+
+ if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 &&
+ inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 &&
+ inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 &&
+ inptr[DCTSIZE*7] == 0) {
+ /* AC terms all zero */
+ int dcval = (int) DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+
+ wsptr[DCTSIZE*0] = dcval;
+ wsptr[DCTSIZE*1] = dcval;
+ wsptr[DCTSIZE*2] = dcval;
+ wsptr[DCTSIZE*3] = dcval;
+ wsptr[DCTSIZE*4] = dcval;
+ wsptr[DCTSIZE*5] = dcval;
+ wsptr[DCTSIZE*6] = dcval;
+ wsptr[DCTSIZE*7] = dcval;
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ continue;
+ }
+
+ /* Even part */
+
+ tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+ tmp1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
+ tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
+ tmp3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
+
+ tmp10 = tmp0 + tmp2; /* phase 3 */
+ tmp11 = tmp0 - tmp2;
+
+ tmp13 = tmp1 + tmp3; /* phases 5-3 */
+ tmp12 = MULTIPLY(tmp1 - tmp3, FIX_1_414213562) - tmp13; /* 2*c4 */
+
+ tmp0 = tmp10 + tmp13; /* phase 2 */
+ tmp3 = tmp10 - tmp13;
+ tmp1 = tmp11 + tmp12;
+ tmp2 = tmp11 - tmp12;
+
+ /* Odd part */
+
+ tmp4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
+ tmp5 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
+ tmp6 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
+ tmp7 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
+
+ z13 = tmp6 + tmp5; /* phase 6 */
+ z10 = tmp6 - tmp5;
+ z11 = tmp4 + tmp7;
+ z12 = tmp4 - tmp7;
+
+ tmp7 = z11 + z13; /* phase 5 */
+ tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562); /* 2*c4 */
+
+ z5 = MULTIPLY(z10 + z12, FIX_1_847759065); /* 2*c2 */
+ tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5; /* 2*(c2-c6) */
+ tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5; /* -2*(c2+c6) */
+
+ tmp6 = tmp12 - tmp7; /* phase 2 */
+ tmp5 = tmp11 - tmp6;
+ tmp4 = tmp10 + tmp5;
+
+ wsptr[DCTSIZE*0] = (int) (tmp0 + tmp7);
+ wsptr[DCTSIZE*7] = (int) (tmp0 - tmp7);
+ wsptr[DCTSIZE*1] = (int) (tmp1 + tmp6);
+ wsptr[DCTSIZE*6] = (int) (tmp1 - tmp6);
+ wsptr[DCTSIZE*2] = (int) (tmp2 + tmp5);
+ wsptr[DCTSIZE*5] = (int) (tmp2 - tmp5);
+ wsptr[DCTSIZE*4] = (int) (tmp3 + tmp4);
+ wsptr[DCTSIZE*3] = (int) (tmp3 - tmp4);
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ }
+
+ /* Pass 2: process rows from work array, store into output array. */
+ /* Note that we must descale the results by a factor of 8 == 2**3, */
+ /* and also undo the PASS1_BITS scaling. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < DCTSIZE; ctr++) {
+ outptr = output_buf[ctr] + output_col;
+ /* Rows of zeroes can be exploited in the same way as we did with columns.
+ * However, the column calculation has created many nonzero AC terms, so
+ * the simplification applies less often (typically 5% to 10% of the time).
+ * On machines with very fast multiplication, it's possible that the
+ * test takes more time than it's worth. In that case this section
+ * may be commented out.
+ */
+
+#ifndef NO_ZERO_ROW_TEST
+ if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 0 &&
+ wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) {
+ /* AC terms all zero */
+ JSAMPLE dcval = range_limit[IDESCALE(wsptr[0], PASS1_BITS+3)
+ & RANGE_MASK];
+
+ outptr[0] = dcval;
+ outptr[1] = dcval;
+ outptr[2] = dcval;
+ outptr[3] = dcval;
+ outptr[4] = dcval;
+ outptr[5] = dcval;
+ outptr[6] = dcval;
+ outptr[7] = dcval;
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ continue;
+ }
+#endif
+
+ /* Even part */
+
+ tmp10 = ((DCTELEM) wsptr[0] + (DCTELEM) wsptr[4]);
+ tmp11 = ((DCTELEM) wsptr[0] - (DCTELEM) wsptr[4]);
+
+ tmp13 = ((DCTELEM) wsptr[2] + (DCTELEM) wsptr[6]);
+ tmp12 = MULTIPLY((DCTELEM) wsptr[2] - (DCTELEM) wsptr[6], FIX_1_414213562)
+ - tmp13;
+
+ tmp0 = tmp10 + tmp13;
+ tmp3 = tmp10 - tmp13;
+ tmp1 = tmp11 + tmp12;
+ tmp2 = tmp11 - tmp12;
+
+ /* Odd part */
+
+ z13 = (DCTELEM) wsptr[5] + (DCTELEM) wsptr[3];
+ z10 = (DCTELEM) wsptr[5] - (DCTELEM) wsptr[3];
+ z11 = (DCTELEM) wsptr[1] + (DCTELEM) wsptr[7];
+ z12 = (DCTELEM) wsptr[1] - (DCTELEM) wsptr[7];
+
+ tmp7 = z11 + z13; /* phase 5 */
+ tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562); /* 2*c4 */
+
+ z5 = MULTIPLY(z10 + z12, FIX_1_847759065); /* 2*c2 */
+ tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5; /* 2*(c2-c6) */
+ tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5; /* -2*(c2+c6) */
+
+ tmp6 = tmp12 - tmp7; /* phase 2 */
+ tmp5 = tmp11 - tmp6;
+ tmp4 = tmp10 + tmp5;
+
+ /* Final output stage: scale down by a factor of 8 and range-limit */
+
+ outptr[0] = range_limit[IDESCALE(tmp0 + tmp7, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[7] = range_limit[IDESCALE(tmp0 - tmp7, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[1] = range_limit[IDESCALE(tmp1 + tmp6, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[6] = range_limit[IDESCALE(tmp1 - tmp6, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[2] = range_limit[IDESCALE(tmp2 + tmp5, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[5] = range_limit[IDESCALE(tmp2 - tmp5, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[4] = range_limit[IDESCALE(tmp3 + tmp4, PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[3] = range_limit[IDESCALE(tmp3 - tmp4, PASS1_BITS+3)
+ & RANGE_MASK];
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ }
+}
+
+#endif /* DCT_IFAST_SUPPORTED */
--- /dev/null
+/*
+ * jidctint.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains a slow-but-accurate integer implementation of the
+ * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
+ * must also perform dequantization of the input coefficients.
+ *
+ * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
+ * on each row (or vice versa, but it's more convenient to emit a row at
+ * a time). Direct algorithms are also available, but they are much more
+ * complex and seem not to be any faster when reduced to code.
+ *
+ * This implementation is based on an algorithm described in
+ * C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
+ * Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
+ * Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
+ * The primary algorithm described there uses 11 multiplies and 29 adds.
+ * We use their alternate method with 12 multiplies and 32 adds.
+ * The advantage of this method is that no data path contains more than one
+ * multiplication; this allows a very simple and accurate implementation in
+ * scaled fixed-point arithmetic, with a minimal number of shifts.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef DCT_ISLOW_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/*
+ * The poop on this scaling stuff is as follows:
+ *
+ * Each 1-D IDCT step produces outputs which are a factor of sqrt(N)
+ * larger than the true IDCT outputs. The final outputs are therefore
+ * a factor of N larger than desired; since N=8 this can be cured by
+ * a simple right shift at the end of the algorithm. The advantage of
+ * this arrangement is that we save two multiplications per 1-D IDCT,
+ * because the y0 and y4 inputs need not be divided by sqrt(N).
+ *
+ * We have to do addition and subtraction of the integer inputs, which
+ * is no problem, and multiplication by fractional constants, which is
+ * a problem to do in integer arithmetic. We multiply all the constants
+ * by CONST_SCALE and convert them to integer constants (thus retaining
+ * CONST_BITS bits of precision in the constants). After doing a
+ * multiplication we have to divide the product by CONST_SCALE, with proper
+ * rounding, to produce the correct output. This division can be done
+ * cheaply as a right shift of CONST_BITS bits. We postpone shifting
+ * as long as possible so that partial sums can be added together with
+ * full fractional precision.
+ *
+ * The outputs of the first pass are scaled up by PASS1_BITS bits so that
+ * they are represented to better-than-integral precision. These outputs
+ * require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word
+ * with the recommended scaling. (To scale up 12-bit sample data further, an
+ * intermediate INT32 array would be needed.)
+ *
+ * To avoid overflow of the 32-bit intermediate results in pass 2, we must
+ * have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis
+ * shows that the values given below are the most effective.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define CONST_BITS 13
+#define PASS1_BITS 2
+#else
+#define CONST_BITS 13
+#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
+#endif
+
+/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
+ * causing a lot of useless floating-point operations at run time.
+ * To get around this we use the following pre-calculated constants.
+ * If you change CONST_BITS you may want to add appropriate values.
+ * (With a reasonable C compiler, you can just rely on the FIX() macro...)
+ */
+
+#if CONST_BITS == 13
+#define FIX_0_298631336 ((INT32) 2446) /* FIX(0.298631336) */
+#define FIX_0_390180644 ((INT32) 3196) /* FIX(0.390180644) */
+#define FIX_0_541196100 ((INT32) 4433) /* FIX(0.541196100) */
+#define FIX_0_765366865 ((INT32) 6270) /* FIX(0.765366865) */
+#define FIX_0_899976223 ((INT32) 7373) /* FIX(0.899976223) */
+#define FIX_1_175875602 ((INT32) 9633) /* FIX(1.175875602) */
+#define FIX_1_501321110 ((INT32) 12299) /* FIX(1.501321110) */
+#define FIX_1_847759065 ((INT32) 15137) /* FIX(1.847759065) */
+#define FIX_1_961570560 ((INT32) 16069) /* FIX(1.961570560) */
+#define FIX_2_053119869 ((INT32) 16819) /* FIX(2.053119869) */
+#define FIX_2_562915447 ((INT32) 20995) /* FIX(2.562915447) */
+#define FIX_3_072711026 ((INT32) 25172) /* FIX(3.072711026) */
+#else
+#define FIX_0_298631336 FIX(0.298631336)
+#define FIX_0_390180644 FIX(0.390180644)
+#define FIX_0_541196100 FIX(0.541196100)
+#define FIX_0_765366865 FIX(0.765366865)
+#define FIX_0_899976223 FIX(0.899976223)
+#define FIX_1_175875602 FIX(1.175875602)
+#define FIX_1_501321110 FIX(1.501321110)
+#define FIX_1_847759065 FIX(1.847759065)
+#define FIX_1_961570560 FIX(1.961570560)
+#define FIX_2_053119869 FIX(2.053119869)
+#define FIX_2_562915447 FIX(2.562915447)
+#define FIX_3_072711026 FIX(3.072711026)
+#endif
+
+
+/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
+ * For 8-bit samples with the recommended scaling, all the variable
+ * and constant values involved are no more than 16 bits wide, so a
+ * 16x16->32 bit multiply can be used instead of a full 32x32 multiply.
+ * For 12-bit samples, a full 32-bit multiplication will be needed.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define MULTIPLY(var,const) MULTIPLY16C16(var,const)
+#else
+#define MULTIPLY(var,const) ((var) * (const))
+#endif
+
+
+/* Dequantize a coefficient by multiplying it by the multiplier-table
+ * entry; produce an int result. In this module, both inputs and result
+ * are 16 bits or less, so either int or short multiply will work.
+ */
+
+#define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval))
+
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients.
+ */
+
+GLOBAL(void)
+jpeg_idct_islow (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col)
+{
+ INT32 tmp0, tmp1, tmp2, tmp3;
+ INT32 tmp10, tmp11, tmp12, tmp13;
+ INT32 z1, z2, z3, z4, z5;
+ JCOEFPTR inptr;
+ ISLOW_MULT_TYPE * quantptr;
+ int * wsptr;
+ JSAMPROW outptr;
+ JSAMPLE *range_limit = IDCT_range_limit(cinfo);
+ int ctr;
+ int workspace[DCTSIZE2]; /* buffers data between passes */
+ SHIFT_TEMPS
+
+ /* Pass 1: process columns from input, store into work array. */
+ /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
+ /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+ inptr = coef_block;
+ quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
+ wsptr = workspace;
+ for (ctr = DCTSIZE; ctr > 0; ctr--) {
+ /* Due to quantization, we will usually find that many of the input
+ * coefficients are zero, especially the AC terms. We can exploit this
+ * by short-circuiting the IDCT calculation for any column in which all
+ * the AC terms are zero. In that case each output is equal to the
+ * DC coefficient (with scale factor as needed).
+ * With typical images and quantization tables, half or more of the
+ * column DCT calculations can be simplified this way.
+ */
+
+ if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 &&
+ inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 &&
+ inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 &&
+ inptr[DCTSIZE*7] == 0) {
+ /* AC terms all zero */
+ int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS;
+
+ wsptr[DCTSIZE*0] = dcval;
+ wsptr[DCTSIZE*1] = dcval;
+ wsptr[DCTSIZE*2] = dcval;
+ wsptr[DCTSIZE*3] = dcval;
+ wsptr[DCTSIZE*4] = dcval;
+ wsptr[DCTSIZE*5] = dcval;
+ wsptr[DCTSIZE*6] = dcval;
+ wsptr[DCTSIZE*7] = dcval;
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ continue;
+ }
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+
+ z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
+ z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
+
+ z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
+ tmp2 = z1 + MULTIPLY(z3, - FIX_1_847759065);
+ tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
+
+ z2 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+ z3 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
+
+ tmp0 = (z2 + z3) << CONST_BITS;
+ tmp1 = (z2 - z3) << CONST_BITS;
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
+ */
+
+ tmp0 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
+ tmp1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
+ tmp2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
+ tmp3 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
+
+ z1 = tmp0 + tmp3;
+ z2 = tmp1 + tmp2;
+ z3 = tmp0 + tmp2;
+ z4 = tmp1 + tmp3;
+ z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
+
+ tmp0 = MULTIPLY(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp1 = MULTIPLY(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp2 = MULTIPLY(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp3 = MULTIPLY(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*7] = (int) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*1] = (int) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*6] = (int) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*5] = (int) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*3] = (int) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
+ wsptr[DCTSIZE*4] = (int) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ }
+
+ /* Pass 2: process rows from work array, store into output array. */
+ /* Note that we must descale the results by a factor of 8 == 2**3, */
+ /* and also undo the PASS1_BITS scaling. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < DCTSIZE; ctr++) {
+ outptr = output_buf[ctr] + output_col;
+ /* Rows of zeroes can be exploited in the same way as we did with columns.
+ * However, the column calculation has created many nonzero AC terms, so
+ * the simplification applies less often (typically 5% to 10% of the time).
+ * On machines with very fast multiplication, it's possible that the
+ * test takes more time than it's worth. In that case this section
+ * may be commented out.
+ */
+
+#ifndef NO_ZERO_ROW_TEST
+ if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 0 &&
+ wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) {
+ /* AC terms all zero */
+ JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3)
+ & RANGE_MASK];
+
+ outptr[0] = dcval;
+ outptr[1] = dcval;
+ outptr[2] = dcval;
+ outptr[3] = dcval;
+ outptr[4] = dcval;
+ outptr[5] = dcval;
+ outptr[6] = dcval;
+ outptr[7] = dcval;
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ continue;
+ }
+#endif
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+
+ z2 = (INT32) wsptr[2];
+ z3 = (INT32) wsptr[6];
+
+ z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
+ tmp2 = z1 + MULTIPLY(z3, - FIX_1_847759065);
+ tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
+
+ tmp0 = ((INT32) wsptr[0] + (INT32) wsptr[4]) << CONST_BITS;
+ tmp1 = ((INT32) wsptr[0] - (INT32) wsptr[4]) << CONST_BITS;
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
+ */
+
+ tmp0 = (INT32) wsptr[7];
+ tmp1 = (INT32) wsptr[5];
+ tmp2 = (INT32) wsptr[3];
+ tmp3 = (INT32) wsptr[1];
+
+ z1 = tmp0 + tmp3;
+ z2 = tmp1 + tmp2;
+ z3 = tmp0 + tmp2;
+ z4 = tmp1 + tmp3;
+ z5 = MULTIPLY(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
+
+ tmp0 = MULTIPLY(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp1 = MULTIPLY(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp2 = MULTIPLY(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp3 = MULTIPLY(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp3,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[7] = range_limit[(int) DESCALE(tmp10 - tmp3,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[1] = range_limit[(int) DESCALE(tmp11 + tmp2,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[6] = range_limit[(int) DESCALE(tmp11 - tmp2,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[2] = range_limit[(int) DESCALE(tmp12 + tmp1,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[5] = range_limit[(int) DESCALE(tmp12 - tmp1,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[3] = range_limit[(int) DESCALE(tmp13 + tmp0,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+ outptr[4] = range_limit[(int) DESCALE(tmp13 - tmp0,
+ CONST_BITS+PASS1_BITS+3)
+ & RANGE_MASK];
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ }
+}
+
+#endif /* DCT_ISLOW_SUPPORTED */
--- /dev/null
+/*
+ * jidctred.c
+ *
+ * Copyright (C) 1994-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains inverse-DCT routines that produce reduced-size output:
+ * either 4x4, 2x2, or 1x1 pixels from an 8x8 DCT block.
+ *
+ * The implementation is based on the Loeffler, Ligtenberg and Moschytz (LL&M)
+ * algorithm used in jidctint.c. We simply replace each 8-to-8 1-D IDCT step
+ * with an 8-to-4 step that produces the four averages of two adjacent outputs
+ * (or an 8-to-2 step producing two averages of four outputs, for 2x2 output).
+ * These steps were derived by computing the corresponding values at the end
+ * of the normal LL&M code, then simplifying as much as possible.
+ *
+ * 1x1 is trivial: just take the DC coefficient divided by 8.
+ *
+ * See jidctint.c for additional comments.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+#ifdef IDCT_SCALING_SUPPORTED
+
+
+/*
+ * This module is specialized to the case DCTSIZE = 8.
+ */
+
+#if DCTSIZE != 8
+ Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
+#endif
+
+
+/* Scaling is the same as in jidctint.c. */
+
+#if BITS_IN_JSAMPLE == 8
+#define CONST_BITS 13
+#define PASS1_BITS 2
+#else
+#define CONST_BITS 13
+#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
+#endif
+
+/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
+ * causing a lot of useless floating-point operations at run time.
+ * To get around this we use the following pre-calculated constants.
+ * If you change CONST_BITS you may want to add appropriate values.
+ * (With a reasonable C compiler, you can just rely on the FIX() macro...)
+ */
+
+#if CONST_BITS == 13
+#define FIX_0_211164243 ((INT32) 1730) /* FIX(0.211164243) */
+#define FIX_0_509795579 ((INT32) 4176) /* FIX(0.509795579) */
+#define FIX_0_601344887 ((INT32) 4926) /* FIX(0.601344887) */
+#define FIX_0_720959822 ((INT32) 5906) /* FIX(0.720959822) */
+#define FIX_0_765366865 ((INT32) 6270) /* FIX(0.765366865) */
+#define FIX_0_850430095 ((INT32) 6967) /* FIX(0.850430095) */
+#define FIX_0_899976223 ((INT32) 7373) /* FIX(0.899976223) */
+#define FIX_1_061594337 ((INT32) 8697) /* FIX(1.061594337) */
+#define FIX_1_272758580 ((INT32) 10426) /* FIX(1.272758580) */
+#define FIX_1_451774981 ((INT32) 11893) /* FIX(1.451774981) */
+#define FIX_1_847759065 ((INT32) 15137) /* FIX(1.847759065) */
+#define FIX_2_172734803 ((INT32) 17799) /* FIX(2.172734803) */
+#define FIX_2_562915447 ((INT32) 20995) /* FIX(2.562915447) */
+#define FIX_3_624509785 ((INT32) 29692) /* FIX(3.624509785) */
+#else
+#define FIX_0_211164243 FIX(0.211164243)
+#define FIX_0_509795579 FIX(0.509795579)
+#define FIX_0_601344887 FIX(0.601344887)
+#define FIX_0_720959822 FIX(0.720959822)
+#define FIX_0_765366865 FIX(0.765366865)
+#define FIX_0_850430095 FIX(0.850430095)
+#define FIX_0_899976223 FIX(0.899976223)
+#define FIX_1_061594337 FIX(1.061594337)
+#define FIX_1_272758580 FIX(1.272758580)
+#define FIX_1_451774981 FIX(1.451774981)
+#define FIX_1_847759065 FIX(1.847759065)
+#define FIX_2_172734803 FIX(2.172734803)
+#define FIX_2_562915447 FIX(2.562915447)
+#define FIX_3_624509785 FIX(3.624509785)
+#endif
+
+
+/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
+ * For 8-bit samples with the recommended scaling, all the variable
+ * and constant values involved are no more than 16 bits wide, so a
+ * 16x16->32 bit multiply can be used instead of a full 32x32 multiply.
+ * For 12-bit samples, a full 32-bit multiplication will be needed.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define MULTIPLY(var,const) MULTIPLY16C16(var,const)
+#else
+#define MULTIPLY(var,const) ((var) * (const))
+#endif
+
+
+/* Dequantize a coefficient by multiplying it by the multiplier-table
+ * entry; produce an int result. In this module, both inputs and result
+ * are 16 bits or less, so either int or short multiply will work.
+ */
+
+#define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval))
+
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients,
+ * producing a reduced-size 4x4 output block.
+ */
+
+GLOBAL(void)
+jpeg_idct_4x4 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col)
+{
+ INT32 tmp0, tmp2, tmp10, tmp12;
+ INT32 z1, z2, z3, z4;
+ JCOEFPTR inptr;
+ ISLOW_MULT_TYPE * quantptr;
+ int * wsptr;
+ JSAMPROW outptr;
+ JSAMPLE *range_limit = IDCT_range_limit(cinfo);
+ int ctr;
+ int workspace[DCTSIZE*4]; /* buffers data between passes */
+ SHIFT_TEMPS
+
+ /* Pass 1: process columns from input, store into work array. */
+
+ inptr = coef_block;
+ quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
+ wsptr = workspace;
+ for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) {
+ /* Don't bother to process column 4, because second pass won't use it */
+ if (ctr == DCTSIZE-4)
+ continue;
+ if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 &&
+ inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*5] == 0 &&
+ inptr[DCTSIZE*6] == 0 && inptr[DCTSIZE*7] == 0) {
+ /* AC terms all zero; we need not examine term 4 for 4x4 output */
+ int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS;
+
+ wsptr[DCTSIZE*0] = dcval;
+ wsptr[DCTSIZE*1] = dcval;
+ wsptr[DCTSIZE*2] = dcval;
+ wsptr[DCTSIZE*3] = dcval;
+
+ continue;
+ }
+
+ /* Even part */
+
+ tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+ tmp0 <<= (CONST_BITS+1);
+
+ z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
+ z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
+
+ tmp2 = MULTIPLY(z2, FIX_1_847759065) + MULTIPLY(z3, - FIX_0_765366865);
+
+ tmp10 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+
+ /* Odd part */
+
+ z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
+ z2 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
+ z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
+ z4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
+
+ tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */
+ + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */
+ + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */
+ + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */
+
+ tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */
+ + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */
+ + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */
+ + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */
+
+ /* Final output stage */
+
+ wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp2, CONST_BITS-PASS1_BITS+1);
+ wsptr[DCTSIZE*3] = (int) DESCALE(tmp10 - tmp2, CONST_BITS-PASS1_BITS+1);
+ wsptr[DCTSIZE*1] = (int) DESCALE(tmp12 + tmp0, CONST_BITS-PASS1_BITS+1);
+ wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 - tmp0, CONST_BITS-PASS1_BITS+1);
+ }
+
+ /* Pass 2: process 4 rows from work array, store into output array. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < 4; ctr++) {
+ outptr = output_buf[ctr] + output_col;
+ /* It's not clear whether a zero row test is worthwhile here ... */
+
+#ifndef NO_ZERO_ROW_TEST
+ if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 &&
+ wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) {
+ /* AC terms all zero */
+ JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3)
+ & RANGE_MASK];
+
+ outptr[0] = dcval;
+ outptr[1] = dcval;
+ outptr[2] = dcval;
+ outptr[3] = dcval;
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ continue;
+ }
+#endif
+
+ /* Even part */
+
+ tmp0 = ((INT32) wsptr[0]) << (CONST_BITS+1);
+
+ tmp2 = MULTIPLY((INT32) wsptr[2], FIX_1_847759065)
+ + MULTIPLY((INT32) wsptr[6], - FIX_0_765366865);
+
+ tmp10 = tmp0 + tmp2;
+ tmp12 = tmp0 - tmp2;
+
+ /* Odd part */
+
+ z1 = (INT32) wsptr[7];
+ z2 = (INT32) wsptr[5];
+ z3 = (INT32) wsptr[3];
+ z4 = (INT32) wsptr[1];
+
+ tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */
+ + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */
+ + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */
+ + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */
+
+ tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */
+ + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */
+ + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */
+ + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */
+
+ /* Final output stage */
+
+ outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp2,
+ CONST_BITS+PASS1_BITS+3+1)
+ & RANGE_MASK];
+ outptr[3] = range_limit[(int) DESCALE(tmp10 - tmp2,
+ CONST_BITS+PASS1_BITS+3+1)
+ & RANGE_MASK];
+ outptr[1] = range_limit[(int) DESCALE(tmp12 + tmp0,
+ CONST_BITS+PASS1_BITS+3+1)
+ & RANGE_MASK];
+ outptr[2] = range_limit[(int) DESCALE(tmp12 - tmp0,
+ CONST_BITS+PASS1_BITS+3+1)
+ & RANGE_MASK];
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ }
+}
+
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients,
+ * producing a reduced-size 2x2 output block.
+ */
+
+GLOBAL(void)
+jpeg_idct_2x2 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col)
+{
+ INT32 tmp0, tmp10, z1;
+ JCOEFPTR inptr;
+ ISLOW_MULT_TYPE * quantptr;
+ int * wsptr;
+ JSAMPROW outptr;
+ JSAMPLE *range_limit = IDCT_range_limit(cinfo);
+ int ctr;
+ int workspace[DCTSIZE*2]; /* buffers data between passes */
+ SHIFT_TEMPS
+
+ /* Pass 1: process columns from input, store into work array. */
+
+ inptr = coef_block;
+ quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
+ wsptr = workspace;
+ for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) {
+ /* Don't bother to process columns 2,4,6 */
+ if (ctr == DCTSIZE-2 || ctr == DCTSIZE-4 || ctr == DCTSIZE-6)
+ continue;
+ if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*3] == 0 &&
+ inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*7] == 0) {
+ /* AC terms all zero; we need not examine terms 2,4,6 for 2x2 output */
+ int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS;
+
+ wsptr[DCTSIZE*0] = dcval;
+ wsptr[DCTSIZE*1] = dcval;
+
+ continue;
+ }
+
+ /* Even part */
+
+ z1 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
+ tmp10 = z1 << (CONST_BITS+2);
+
+ /* Odd part */
+
+ z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
+ tmp0 = MULTIPLY(z1, - FIX_0_720959822); /* sqrt(2) * (c7-c5+c3-c1) */
+ z1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
+ tmp0 += MULTIPLY(z1, FIX_0_850430095); /* sqrt(2) * (-c1+c3+c5+c7) */
+ z1 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
+ tmp0 += MULTIPLY(z1, - FIX_1_272758580); /* sqrt(2) * (-c1+c3-c5-c7) */
+ z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
+ tmp0 += MULTIPLY(z1, FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */
+
+ /* Final output stage */
+
+ wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp0, CONST_BITS-PASS1_BITS+2);
+ wsptr[DCTSIZE*1] = (int) DESCALE(tmp10 - tmp0, CONST_BITS-PASS1_BITS+2);
+ }
+
+ /* Pass 2: process 2 rows from work array, store into output array. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < 2; ctr++) {
+ outptr = output_buf[ctr] + output_col;
+ /* It's not clear whether a zero row test is worthwhile here ... */
+
+#ifndef NO_ZERO_ROW_TEST
+ if (wsptr[1] == 0 && wsptr[3] == 0 && wsptr[5] == 0 && wsptr[7] == 0) {
+ /* AC terms all zero */
+ JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3)
+ & RANGE_MASK];
+
+ outptr[0] = dcval;
+ outptr[1] = dcval;
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ continue;
+ }
+#endif
+
+ /* Even part */
+
+ tmp10 = ((INT32) wsptr[0]) << (CONST_BITS+2);
+
+ /* Odd part */
+
+ tmp0 = MULTIPLY((INT32) wsptr[7], - FIX_0_720959822) /* sqrt(2) * (c7-c5+c3-c1) */
+ + MULTIPLY((INT32) wsptr[5], FIX_0_850430095) /* sqrt(2) * (-c1+c3+c5+c7) */
+ + MULTIPLY((INT32) wsptr[3], - FIX_1_272758580) /* sqrt(2) * (-c1+c3-c5-c7) */
+ + MULTIPLY((INT32) wsptr[1], FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */
+
+ /* Final output stage */
+
+ outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp0,
+ CONST_BITS+PASS1_BITS+3+2)
+ & RANGE_MASK];
+ outptr[1] = range_limit[(int) DESCALE(tmp10 - tmp0,
+ CONST_BITS+PASS1_BITS+3+2)
+ & RANGE_MASK];
+
+ wsptr += DCTSIZE; /* advance pointer to next row */
+ }
+}
+
+
+/*
+ * Perform dequantization and inverse DCT on one block of coefficients,
+ * producing a reduced-size 1x1 output block.
+ */
+
+GLOBAL(void)
+jpeg_idct_1x1 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col)
+{
+ int dcval;
+ ISLOW_MULT_TYPE * quantptr;
+ JSAMPLE *range_limit = IDCT_range_limit(cinfo);
+ SHIFT_TEMPS
+
+ /* We hardly need an inverse DCT routine for this: just take the
+ * average pixel value, which is one-eighth of the DC coefficient.
+ */
+ quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
+ dcval = DEQUANTIZE(coef_block[0], quantptr[0]);
+ dcval = (int) DESCALE((INT32) dcval, 3);
+
+ output_buf[0][output_col] = range_limit[dcval & RANGE_MASK];
+}
+
+#endif /* IDCT_SCALING_SUPPORTED */
--- /dev/null
+/*
+ * jinclude.h
+ *
+ * Copyright (C) 1991-1994, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file exists to provide a single place to fix any problems with
+ * including the wrong system include files. (Common problems are taken
+ * care of by the standard jconfig symbols, but on really weird systems
+ * you may have to edit this file.)
+ *
+ * NOTE: this file is NOT intended to be included by applications using the
+ * JPEG library. Most applications need only include jpeglib.h.
+ */
+
+
+/* Include auto-config file to find out which system include files we need. */
+
+#include "jconfig.h" /* auto configuration options */
+#define JCONFIG_INCLUDED /* so that jpeglib.h doesn't do it again */
+
+/*
+ * We need the NULL macro and size_t typedef.
+ * On an ANSI-conforming system it is sufficient to include <stddef.h>.
+ * Otherwise, we get them from <stdlib.h> or <stdio.h>; we may have to
+ * pull in <sys/types.h> as well.
+ * Note that the core JPEG library does not require <stdio.h>;
+ * only the default error handler and data source/destination modules do.
+ * But we must pull it in because of the references to FILE in jpeglib.h.
+ * You can remove those references if you want to compile without <stdio.h>.
+ */
+
+#ifdef HAVE_STDDEF_H
+#include <stddef.h>
+#endif
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+#ifdef NEED_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#include <stdio.h>
+
+/*
+ * We need memory copying and zeroing functions, plus strncpy().
+ * ANSI and System V implementations declare these in <string.h>.
+ * BSD doesn't have the mem() functions, but it does have bcopy()/bzero().
+ * Some systems may declare memset and memcpy in <memory.h>.
+ *
+ * NOTE: we assume the size parameters to these functions are of type size_t.
+ * Change the casts in these macros if not!
+ */
+
+#ifdef NEED_BSD_STRINGS
+
+#include <strings.h>
+#define MEMZERO(target,size) bzero((void *)(target), (size_t)(size))
+#define MEMCOPY(dest,src,size) bcopy((const void *)(src), (void *)(dest), (size_t)(size))
+
+#else /* not BSD, assume ANSI/SysV string lib */
+
+#include <string.h>
+#define MEMZERO(target,size) memset((void *)(target), 0, (size_t)(size))
+#define MEMCOPY(dest,src,size) memcpy((void *)(dest), (const void *)(src), (size_t)(size))
+
+#endif
+
+/*
+ * In ANSI C, and indeed any rational implementation, size_t is also the
+ * type returned by sizeof(). However, it seems there are some irrational
+ * implementations out there, in which sizeof() returns an int even though
+ * size_t is defined as long or unsigned long. To ensure consistent results
+ * we always use this SIZEOF() macro in place of using sizeof() directly.
+ */
+
+#define SIZEOF(object) ((size_t) sizeof(object))
+
+/*
+ * The modules that use fread() and fwrite() always invoke them through
+ * these macros. On some systems you may need to twiddle the argument casts.
+ * CAUTION: argument order is different from underlying functions!
+ */
+
+#define JFREAD(file,buf,sizeofbuf) \
+ ((size_t) fread((void *) (buf), (size_t) 1, (size_t) (sizeofbuf), (file)))
+#define JFWRITE(file,buf,sizeofbuf) \
+ ((size_t) fwrite((const void *) (buf), (size_t) 1, (size_t) (sizeofbuf), (file)))
--- /dev/null
+/*
+ * jlossls.h
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This include file contains common declarations for the lossless JPEG
+ * codec modules.
+ */
+
+#ifndef JLOSSLS_H
+#define JLOSSLS_H
+
+
+/*
+ * Table H.1: Predictors for lossless coding.
+ */
+
+#define PREDICTOR1 Ra
+#define PREDICTOR2 Rb
+#define PREDICTOR3 Rc
+#define PREDICTOR4 (int) ((INT32) Ra + (INT32) Rb - (INT32) Rc)
+#define PREDICTOR5 (int) ((INT32) Ra + RIGHT_SHIFT((INT32) Rb - (INT32) Rc, 1))
+#define PREDICTOR6 (int) ((INT32) Rb + RIGHT_SHIFT((INT32) Ra - (INT32) Rc, 1))
+#define PREDICTOR7 (int) RIGHT_SHIFT((INT32) Ra + (INT32) Rb, 1)
+
+
+typedef JMETHOD(void, predict_difference_method_ptr,
+ (j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW prev_row,
+ JDIFFROW diff_buf, JDIMENSION width));
+
+typedef JMETHOD(void, scaler_method_ptr,
+ (j_compress_ptr cinfo, int ci,
+ JSAMPROW input_buf, JSAMPROW output_buf,
+ JDIMENSION width));
+
+/* Lossless-specific compression codec (compressor proper) */
+typedef struct {
+ struct jpeg_c_codec pub; /* public fields */
+
+
+ /* Difference buffer control */
+ JMETHOD(void, diff_start_pass, (j_compress_ptr cinfo,
+ J_BUF_MODE pass_mode));
+
+ /* Pointer to data which is private to diff controller */
+ void *diff_private;
+
+
+ /* Entropy encoding */
+ JMETHOD(JDIMENSION, entropy_encode_mcus, (j_compress_ptr cinfo,
+ JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num,
+ JDIMENSION MCU_col_num,
+ JDIMENSION nMCU));
+
+ /* Pointer to data which is private to entropy module */
+ void *entropy_private;
+
+
+ /* Prediction, differencing */
+ JMETHOD(void, predict_start_pass, (j_compress_ptr cinfo));
+
+ /* It is useful to allow each component to have a separate diff method. */
+ predict_difference_method_ptr predict_difference[MAX_COMPONENTS];
+
+ /* Pointer to data which is private to predictor module */
+ void *pred_private;
+
+ /* Sample scaling */
+ JMETHOD(void, scaler_start_pass, (j_compress_ptr cinfo));
+ JMETHOD(void, scaler_scale, (j_compress_ptr cinfo,
+ JSAMPROW input_buf, JSAMPROW output_buf,
+ JDIMENSION width));
+
+ /* Pointer to data which is private to scaler module */
+ void *scaler_private;
+
+} jpeg_lossless_c_codec;
+
+typedef jpeg_lossless_c_codec * j_lossless_c_ptr;
+
+
+typedef JMETHOD(void, predict_undifference_method_ptr,
+ (j_decompress_ptr cinfo, int comp_index,
+ JDIFFROW diff_buf, JDIFFROW prev_row,
+ JDIFFROW undiff_buf, JDIMENSION width));
+
+/* Lossless-specific decompression codec (decompressor proper) */
+typedef struct {
+ struct jpeg_d_codec pub; /* public fields */
+
+
+ /* Difference buffer control */
+ JMETHOD(void, diff_start_input_pass, (j_decompress_ptr cinfo));
+
+ /* Pointer to data which is private to diff controller */
+ void *diff_private;
+
+
+ /* Entropy decoding */
+ JMETHOD(void, entropy_start_pass, (j_decompress_ptr cinfo));
+ JMETHOD(boolean, entropy_process_restart, (j_decompress_ptr cinfo));
+ JMETHOD(JDIMENSION, entropy_decode_mcus, (j_decompress_ptr cinfo,
+ JDIFFIMAGE diff_buf,
+ JDIMENSION MCU_row_num,
+ JDIMENSION MCU_col_num,
+ JDIMENSION nMCU));
+
+ /* Pointer to data which is private to entropy module */
+ void *entropy_private;
+
+
+ /* Prediction, undifferencing */
+ JMETHOD(void, predict_start_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, predict_process_restart, (j_decompress_ptr cinfo));
+
+ /* It is useful to allow each component to have a separate undiff method. */
+ predict_undifference_method_ptr predict_undifference[MAX_COMPONENTS];
+
+ /* Pointer to data which is private to predictor module */
+ void *pred_private;
+
+ /* Sample scaling */
+ JMETHOD(void, scaler_start_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, scaler_scale, (j_decompress_ptr cinfo,
+ JDIFFROW diff_buf, JSAMPROW output_buf,
+ JDIMENSION width));
+
+ /* Pointer to data which is private to scaler module */
+ void *scaler_private;
+
+} jpeg_lossless_d_codec;
+
+typedef jpeg_lossless_d_codec * j_lossless_d_ptr;
+
+
+/* Compression module initialization routines */
+EXTERN(void) jinit_lossless_c_codec JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_lhuff_encoder JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_differencer JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_c_scaler JPP((j_compress_ptr cinfo));
+/* Decompression module initialization routines */
+EXTERN(void) jinit_lossless_d_codec JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_lhuff_decoder JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_undifferencer JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_d_scaler JPP((j_decompress_ptr cinfo));
+
+#endif /* JLOSSLS_H */
--- /dev/null
+/*
+ * jlossy.h
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This include file contains common declarations for the lossy (DCT-based)
+ * JPEG codec modules.
+ */
+
+#ifndef JLOSSY_H
+#define JLOSSY_H
+
+
+/* Lossy-specific compression codec (compressor proper) */
+typedef struct {
+ struct jpeg_c_codec pub; /* public fields */
+
+
+ /* Coefficient buffer control */
+ JMETHOD(void, coef_start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
+ /* JMETHOD(boolean, coef_compress_data, (j_compress_ptr cinfo,
+ JSAMPIMAGE input_buf));*/
+
+ /* Pointer to data which is private to coef module */
+ void *coef_private;
+
+
+ /* Forward DCT (also controls coefficient quantization) */
+ JMETHOD(void, fdct_start_pass, (j_compress_ptr cinfo));
+ /* perhaps this should be an array??? */
+ JMETHOD(void, fdct_forward_DCT, (j_compress_ptr cinfo,
+ jpeg_component_info * compptr,
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks));
+
+ /* Pointer to data which is private to fdct module */
+ void *fdct_private;
+
+
+ /* Entropy encoding */
+ JMETHOD(boolean, entropy_encode_mcu, (j_compress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+
+ /* Pointer to data which is private to entropy module */
+ void *entropy_private;
+
+} jpeg_lossy_c_codec;
+
+typedef jpeg_lossy_c_codec * j_lossy_c_ptr;
+
+
+
+typedef JMETHOD(void, inverse_DCT_method_ptr,
+ (j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block,
+ JSAMPARRAY output_buf, JDIMENSION output_col));
+
+/* Lossy-specific decompression codec (decompressor proper) */
+typedef struct {
+ struct jpeg_d_codec pub; /* public fields */
+
+
+ /* Coefficient buffer control */
+ JMETHOD(void, coef_start_input_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, coef_start_output_pass, (j_decompress_ptr cinfo));
+
+ /* Pointer to array of coefficient virtual arrays, or NULL if none */
+ jvirt_barray_ptr *coef_arrays;
+
+ /* Pointer to data which is private to coef module */
+ void *coef_private;
+
+
+ /* Entropy decoding */
+ JMETHOD(void, entropy_start_pass, (j_decompress_ptr cinfo));
+ JMETHOD(boolean, entropy_decode_mcu, (j_decompress_ptr cinfo,
+ JBLOCKROW *MCU_data));
+
+ /* This is here to share code between baseline and progressive decoders; */
+ /* other modules probably should not use it */
+ boolean entropy_insufficient_data; /* set TRUE after emitting warning */
+
+ /* Pointer to data which is private to entropy module */
+ void *entropy_private;
+
+
+ /* Inverse DCT (also performs dequantization) */
+ JMETHOD(void, idct_start_pass, (j_decompress_ptr cinfo));
+
+ /* It is useful to allow each component to have a separate IDCT method. */
+ inverse_DCT_method_ptr inverse_DCT[MAX_COMPONENTS];
+
+ /* Pointer to data which is private to idct module */
+ void *idct_private;
+
+} jpeg_lossy_d_codec;
+
+typedef jpeg_lossy_d_codec * j_lossy_d_ptr;
+
+
+/* Compression module initialization routines */
+EXTERN(void) jinit_lossy_c_codec JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_c_coef_controller JPP((j_compress_ptr cinfo,
+ boolean need_full_buffer));
+EXTERN(void) jinit_forward_dct JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_shuff_encoder JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_phuff_encoder JPP((j_compress_ptr cinfo));
+
+/* Decompression module initialization routines */
+EXTERN(void) jinit_lossy_d_codec JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_d_coef_controller JPP((j_decompress_ptr cinfo,
+ boolean need_full_buffer));
+EXTERN(void) jinit_shuff_decoder JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_phuff_decoder JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_inverse_dct JPP((j_decompress_ptr cinfo));
+
+#endif /* JLOSSY_H */
--- /dev/null
+/*
+ * jmemmgr.c
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains the JPEG system-independent memory management
+ * routines. This code is usable across a wide variety of machines; most
+ * of the system dependencies have been isolated in a separate file.
+ * The major functions provided here are:
+ * * pool-based allocation and freeing of memory;
+ * * policy decisions about how to divide available memory among the
+ * virtual arrays;
+ * * control logic for swapping virtual arrays between main memory and
+ * backing storage.
+ * The separate system-dependent file provides the actual backing-storage
+ * access code, and it contains the policy decision about how much total
+ * main memory to use.
+ * This file is system-dependent in the sense that some of its functions
+ * are unnecessary in some systems. For example, if there is enough virtual
+ * memory so that backing storage will never be used, much of the virtual
+ * array control logic could be removed. (Of course, if you have that much
+ * memory then you shouldn't care about a little bit of unused code...)
+ */
+
+#define JPEG_INTERNALS
+#define AM_MEMORY_MANAGER /* we define jvirt_Xarray_control structs */
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jmemsys.h" /* import the system-dependent declarations */
+
+#ifndef NO_GETENV
+#ifndef HAVE_STDLIB_H /* <stdlib.h> should declare getenv() */
+extern char * getenv JPP((const char * name));
+#endif
+#endif
+
+
+/*
+ * Some important notes:
+ * The allocation routines provided here must never return NULL.
+ * They should exit to error_exit if unsuccessful.
+ *
+ * It's not a good idea to try to merge the sarray, barray and darray
+ * routines, even though they are textually almost the same, because
+ * samples are usually stored as bytes while coefficients and differenced
+ * are shorts or ints. Thus, in machines where byte pointers have a
+ * different representation from word pointers, the resulting machine
+ * code could not be the same.
+ */
+
+
+/*
+ * Many machines require storage alignment: longs must start on 4-byte
+ * boundaries, doubles on 8-byte boundaries, etc. On such machines, malloc()
+ * always returns pointers that are multiples of the worst-case alignment
+ * requirement, and we had better do so too.
+ * There isn't any really portable way to determine the worst-case alignment
+ * requirement. This module assumes that the alignment requirement is
+ * multiples of sizeof(ALIGN_TYPE).
+ * By default, we define ALIGN_TYPE as double. This is necessary on some
+ * workstations (where doubles really do need 8-byte alignment) and will work
+ * fine on nearly everything. If your machine has lesser alignment needs,
+ * you can save a few bytes by making ALIGN_TYPE smaller.
+ * The only place I know of where this will NOT work is certain Macintosh
+ * 680x0 compilers that define double as a 10-byte IEEE extended float.
+ * Doing 10-byte alignment is counterproductive because longwords won't be
+ * aligned well. Put "#define ALIGN_TYPE long" in jconfig.h if you have
+ * such a compiler.
+ */
+
+#ifndef ALIGN_TYPE /* so can override from jconfig.h */
+#define ALIGN_TYPE double
+#endif
+
+
+/*
+ * We allocate objects from "pools", where each pool is gotten with a single
+ * request to jpeg_get_small() or jpeg_get_large(). There is no per-object
+ * overhead within a pool, except for alignment padding. Each pool has a
+ * header with a link to the next pool of the same class.
+ * Small and large pool headers are identical except that the latter's
+ * link pointer must be FAR on 80x86 machines.
+ * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
+ * field. This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
+ * of the alignment requirement of ALIGN_TYPE.
+ */
+
+typedef union small_pool_struct * small_pool_ptr;
+
+typedef union small_pool_struct {
+ struct {
+ small_pool_ptr next; /* next in list of pools */
+ size_t bytes_used; /* how many bytes already used within pool */
+ size_t bytes_left; /* bytes still available in this pool */
+ } hdr;
+ ALIGN_TYPE dummy; /* included in union to ensure alignment */
+} small_pool_hdr;
+
+typedef union large_pool_struct FAR * large_pool_ptr;
+
+typedef union large_pool_struct {
+ struct {
+ large_pool_ptr next; /* next in list of pools */
+ size_t bytes_used; /* how many bytes already used within pool */
+ size_t bytes_left; /* bytes still available in this pool */
+ } hdr;
+ ALIGN_TYPE dummy; /* included in union to ensure alignment */
+} large_pool_hdr;
+
+
+/*
+ * Here is the full definition of a memory manager object.
+ */
+
+typedef struct {
+ struct jpeg_memory_mgr pub; /* public fields */
+
+ /* Each pool identifier (lifetime class) names a linked list of pools. */
+ small_pool_ptr small_list[JPOOL_NUMPOOLS];
+ large_pool_ptr large_list[JPOOL_NUMPOOLS];
+
+ /* Since we only have one lifetime class of virtual arrays, only one
+ * linked list is necessary (for each datatype). Note that the virtual
+ * array control blocks being linked together are actually stored somewhere
+ * in the small-pool list.
+ */
+ jvirt_sarray_ptr virt_sarray_list;
+ jvirt_barray_ptr virt_barray_list;
+
+ /* This counts total space obtained from jpeg_get_small/large */
+ long total_space_allocated;
+
+ /* alloc_sarray and alloc_barray set this value for use by virtual
+ * array routines.
+ */
+ JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
+} my_memory_mgr;
+
+typedef my_memory_mgr * my_mem_ptr;
+
+
+/*
+ * The control blocks for virtual arrays.
+ * Note that these blocks are allocated in the "small" pool area.
+ * System-dependent info for the associated backing store (if any) is hidden
+ * inside the backing_store_info struct.
+ */
+
+struct jvirt_sarray_control {
+ JSAMPARRAY mem_buffer; /* => the in-memory buffer */
+ JDIMENSION rows_in_array; /* total virtual array height */
+ JDIMENSION samplesperrow; /* width of array (and of memory buffer) */
+ JDIMENSION maxaccess; /* max rows accessed by access_virt_sarray */
+ JDIMENSION rows_in_mem; /* height of memory buffer */
+ JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
+ JDIMENSION cur_start_row; /* first logical row # in the buffer */
+ JDIMENSION first_undef_row; /* row # of first uninitialized row */
+ boolean pre_zero; /* pre-zero mode requested? */
+ boolean dirty; /* do current buffer contents need written? */
+ boolean b_s_open; /* is backing-store data valid? */
+ jvirt_sarray_ptr next; /* link to next virtual sarray control block */
+ backing_store_info b_s_info; /* System-dependent control info */
+};
+
+struct jvirt_barray_control {
+ JBLOCKARRAY mem_buffer; /* => the in-memory buffer */
+ JDIMENSION rows_in_array; /* total virtual array height */
+ JDIMENSION blocksperrow; /* width of array (and of memory buffer) */
+ JDIMENSION maxaccess; /* max rows accessed by access_virt_barray */
+ JDIMENSION rows_in_mem; /* height of memory buffer */
+ JDIMENSION rowsperchunk; /* allocation chunk size in mem_buffer */
+ JDIMENSION cur_start_row; /* first logical row # in the buffer */
+ JDIMENSION first_undef_row; /* row # of first uninitialized row */
+ boolean pre_zero; /* pre-zero mode requested? */
+ boolean dirty; /* do current buffer contents need written? */
+ boolean b_s_open; /* is backing-store data valid? */
+ jvirt_barray_ptr next; /* link to next virtual barray control block */
+ backing_store_info b_s_info; /* System-dependent control info */
+};
+
+
+#ifdef MEM_STATS /* optional extra stuff for statistics */
+
+LOCAL(void)
+print_mem_stats (j_common_ptr cinfo, int pool_id)
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ small_pool_ptr shdr_ptr;
+ large_pool_ptr lhdr_ptr;
+
+ /* Since this is only a debugging stub, we can cheat a little by using
+ * fprintf directly rather than going through the trace message code.
+ * This is helpful because message parm array can't handle longs.
+ */
+ fprintf(stderr, "Freeing pool %d, total space = %ld\n",
+ pool_id, mem->total_space_allocated);
+
+ for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
+ lhdr_ptr = lhdr_ptr->hdr.next) {
+ fprintf(stderr, " Large chunk used %ld\n",
+ (long) lhdr_ptr->hdr.bytes_used);
+ }
+
+ for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
+ shdr_ptr = shdr_ptr->hdr.next) {
+ fprintf(stderr, " Small chunk used %ld free %ld\n",
+ (long) shdr_ptr->hdr.bytes_used,
+ (long) shdr_ptr->hdr.bytes_left);
+ }
+}
+
+#endif /* MEM_STATS */
+
+
+LOCAL(void)
+out_of_memory (j_common_ptr cinfo, int which)
+/* Report an out-of-memory error and stop execution */
+/* If we compiled MEM_STATS support, report alloc requests before dying */
+{
+#ifdef MEM_STATS
+ cinfo->err->trace_level = 2; /* force self_destruct to report stats */
+#endif
+ ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
+}
+
+
+/*
+ * Allocation of "small" objects.
+ *
+ * For these, we use pooled storage. When a new pool must be created,
+ * we try to get enough space for the current request plus a "slop" factor,
+ * where the slop will be the amount of leftover space in the new pool.
+ * The speed vs. space tradeoff is largely determined by the slop values.
+ * A different slop value is provided for each pool class (lifetime),
+ * and we also distinguish the first pool of a class from later ones.
+ * NOTE: the values given work fairly well on both 16- and 32-bit-int
+ * machines, but may be too small if longs are 64 bits or more.
+ */
+
+static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
+{
+ 1600, /* first PERMANENT pool */
+ 16000 /* first IMAGE pool */
+};
+
+static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
+{
+ 0, /* additional PERMANENT pools */
+ 5000 /* additional IMAGE pools */
+};
+
+#define MIN_SLOP 50 /* greater than 0 to avoid futile looping */
+
+
+METHODDEF(void *)
+alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
+/* Allocate a "small" object */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ small_pool_ptr hdr_ptr, prev_hdr_ptr;
+ char * data_ptr;
+ size_t odd_bytes, min_request, slop;
+
+ /* Check for unsatisfiable request (do now to ensure no overflow below) */
+ if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
+ out_of_memory(cinfo, 1); /* request exceeds malloc's ability */
+
+ /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
+ odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
+ if (odd_bytes > 0)
+ sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
+
+ /* See if space is available in any existing pool */
+ if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
+ ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
+ prev_hdr_ptr = NULL;
+ hdr_ptr = mem->small_list[pool_id];
+ while (hdr_ptr != NULL) {
+ if (hdr_ptr->hdr.bytes_left >= sizeofobject)
+ break; /* found pool with enough space */
+ prev_hdr_ptr = hdr_ptr;
+ hdr_ptr = hdr_ptr->hdr.next;
+ }
+
+ /* Time to make a new pool? */
+ if (hdr_ptr == NULL) {
+ /* min_request is what we need now, slop is what will be leftover */
+ min_request = sizeofobject + SIZEOF(small_pool_hdr);
+ if (prev_hdr_ptr == NULL) /* first pool in class? */
+ slop = first_pool_slop[pool_id];
+ else
+ slop = extra_pool_slop[pool_id];
+ /* Don't ask for more than MAX_ALLOC_CHUNK */
+ if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
+ slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
+ /* Try to get space, if fail reduce slop and try again */
+ for (;;) {
+ hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
+ if (hdr_ptr != NULL)
+ break;
+ slop /= 2;
+ if (slop < MIN_SLOP) /* give up when it gets real small */
+ out_of_memory(cinfo, 2); /* jpeg_get_small failed */
+ }
+ mem->total_space_allocated += min_request + slop;
+ /* Success, initialize the new pool header and add to end of list */
+ hdr_ptr->hdr.next = NULL;
+ hdr_ptr->hdr.bytes_used = 0;
+ hdr_ptr->hdr.bytes_left = sizeofobject + slop;
+ if (prev_hdr_ptr == NULL) /* first pool in class? */
+ mem->small_list[pool_id] = hdr_ptr;
+ else
+ prev_hdr_ptr->hdr.next = hdr_ptr;
+ }
+
+ /* OK, allocate the object from the current pool */
+ data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
+ data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
+ hdr_ptr->hdr.bytes_used += sizeofobject;
+ hdr_ptr->hdr.bytes_left -= sizeofobject;
+
+ return (void *) data_ptr;
+}
+
+
+/*
+ * Allocation of "large" objects.
+ *
+ * The external semantics of these are the same as "small" objects,
+ * except that FAR pointers are used on 80x86. However the pool
+ * management heuristics are quite different. We assume that each
+ * request is large enough that it may as well be passed directly to
+ * jpeg_get_large; the pool management just links everything together
+ * so that we can free it all on demand.
+ * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
+ * structures. The routines that create these structures (see below)
+ * deliberately bunch rows together to ensure a large request size.
+ */
+
+METHODDEF(void FAR *)
+alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
+/* Allocate a "large" object */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ large_pool_ptr hdr_ptr;
+ size_t odd_bytes;
+
+ /* Check for unsatisfiable request (do now to ensure no overflow below) */
+ if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
+ out_of_memory(cinfo, 3); /* request exceeds malloc's ability */
+
+ /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
+ odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
+ if (odd_bytes > 0)
+ sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
+
+ /* Always make a new pool */
+ if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
+ ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
+
+ hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
+ SIZEOF(large_pool_hdr));
+ if (hdr_ptr == NULL)
+ out_of_memory(cinfo, 4); /* jpeg_get_large failed */
+ mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr);
+
+ /* Success, initialize the new pool header and add to list */
+ hdr_ptr->hdr.next = mem->large_list[pool_id];
+ /* We maintain space counts in each pool header for statistical purposes,
+ * even though they are not needed for allocation.
+ */
+ hdr_ptr->hdr.bytes_used = sizeofobject;
+ hdr_ptr->hdr.bytes_left = 0;
+ mem->large_list[pool_id] = hdr_ptr;
+
+ return (void FAR *) (hdr_ptr + 1); /* point to first data byte in pool */
+}
+
+
+/*
+ * Creation of 2-D sample arrays.
+ * The pointers are in near heap, the samples themselves in FAR heap.
+ *
+ * To minimize allocation overhead and to allow I/O of large contiguous
+ * blocks, we allocate the sample rows in groups of as many rows as possible
+ * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
+ * NB: the virtual array control routines, later in this file, know about
+ * this chunking of rows. The rowsperchunk value is left in the mem manager
+ * object so that it can be saved away if this sarray is the workspace for
+ * a virtual array.
+ */
+
+METHODDEF(JSAMPARRAY)
+alloc_sarray (j_common_ptr cinfo, int pool_id,
+ JDIMENSION samplesperrow, JDIMENSION numrows)
+/* Allocate a 2-D sample array */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ JSAMPARRAY result;
+ JSAMPROW workspace;
+ JDIMENSION rowsperchunk, currow, i;
+ long ltemp;
+
+ /* Calculate max # of rows allowed in one allocation chunk */
+ ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
+ ((long) samplesperrow * SIZEOF(JSAMPLE));
+ if (ltemp <= 0)
+ ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
+ if (ltemp < (long) numrows)
+ rowsperchunk = (JDIMENSION) ltemp;
+ else
+ rowsperchunk = numrows;
+ mem->last_rowsperchunk = rowsperchunk;
+
+ /* Get space for row pointers (small object) */
+ result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
+ (size_t) (numrows * SIZEOF(JSAMPROW)));
+
+ /* Get the rows themselves (large objects) */
+ currow = 0;
+ while (currow < numrows) {
+ rowsperchunk = MIN(rowsperchunk, numrows - currow);
+ workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
+ (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
+ * SIZEOF(JSAMPLE)));
+ for (i = rowsperchunk; i > 0; i--) {
+ result[currow++] = workspace;
+ workspace += samplesperrow;
+ }
+ }
+
+ return result;
+}
+
+
+/*
+ * Creation of 2-D coefficient-block arrays.
+ * This is essentially the same as the code for sample arrays, above.
+ */
+
+METHODDEF(JBLOCKARRAY)
+alloc_barray (j_common_ptr cinfo, int pool_id,
+ JDIMENSION blocksperrow, JDIMENSION numrows)
+/* Allocate a 2-D coefficient-block array */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ JBLOCKARRAY result;
+ JBLOCKROW workspace;
+ JDIMENSION rowsperchunk, currow, i;
+ long ltemp;
+
+ /* Calculate max # of rows allowed in one allocation chunk */
+ ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
+ ((long) blocksperrow * SIZEOF(JBLOCK));
+ if (ltemp <= 0)
+ ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
+ if (ltemp < (long) numrows)
+ rowsperchunk = (JDIMENSION) ltemp;
+ else
+ rowsperchunk = numrows;
+ mem->last_rowsperchunk = rowsperchunk;
+
+ /* Get space for row pointers (small object) */
+ result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
+ (size_t) (numrows * SIZEOF(JBLOCKROW)));
+
+ /* Get the rows themselves (large objects) */
+ currow = 0;
+ while (currow < numrows) {
+ rowsperchunk = MIN(rowsperchunk, numrows - currow);
+ workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
+ (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
+ * SIZEOF(JBLOCK)));
+ for (i = rowsperchunk; i > 0; i--) {
+ result[currow++] = workspace;
+ workspace += blocksperrow;
+ }
+ }
+
+ return result;
+}
+
+
+#ifdef NEED_DARRAY
+
+/*
+ * Creation of 2-D difference arrays.
+ * This is essentially the same as the code for sample arrays, above.
+ */
+
+METHODDEF(JDIFFARRAY)
+alloc_darray (j_common_ptr cinfo, int pool_id,
+ JDIMENSION diffsperrow, JDIMENSION numrows)
+/* Allocate a 2-D difference array */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ JDIFFARRAY result;
+ JDIFFROW workspace;
+ JDIMENSION rowsperchunk, currow, i;
+ long ltemp;
+
+ /* Calculate max # of rows allowed in one allocation chunk */
+ ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
+ ((long) diffsperrow * SIZEOF(JDIFF));
+ if (ltemp <= 0)
+ ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
+ if (ltemp < (long) numrows)
+ rowsperchunk = (JDIMENSION) ltemp;
+ else
+ rowsperchunk = numrows;
+ mem->last_rowsperchunk = rowsperchunk;
+
+ /* Get space for row pointers (small object) */
+ result = (JDIFFARRAY) alloc_small(cinfo, pool_id,
+ (size_t) (numrows * SIZEOF(JDIFFROW)));
+
+ /* Get the rows themselves (large objects) */
+ currow = 0;
+ while (currow < numrows) {
+ rowsperchunk = MIN(rowsperchunk, numrows - currow);
+ workspace = (JDIFFROW) alloc_large(cinfo, pool_id,
+ (size_t) ((size_t) rowsperchunk * (size_t) diffsperrow
+ * SIZEOF(JDIFF)));
+ for (i = rowsperchunk; i > 0; i--) {
+ result[currow++] = workspace;
+ workspace += diffsperrow;
+ }
+ }
+
+ return result;
+}
+
+#endif
+
+
+/*
+ * About virtual array management:
+ *
+ * The above "normal" array routines are only used to allocate strip buffers
+ * (as wide as the image, but just a few rows high). Full-image-sized buffers
+ * are handled as "virtual" arrays. The array is still accessed a strip at a
+ * time, but the memory manager must save the whole array for repeated
+ * accesses. The intended implementation is that there is a strip buffer in
+ * memory (as high as is possible given the desired memory limit), plus a
+ * backing file that holds the rest of the array.
+ *
+ * The request_virt_array routines are told the total size of the image and
+ * the maximum number of rows that will be accessed at once. The in-memory
+ * buffer must be at least as large as the maxaccess value.
+ *
+ * The request routines create control blocks but not the in-memory buffers.
+ * That is postponed until realize_virt_arrays is called. At that time the
+ * total amount of space needed is known (approximately, anyway), so free
+ * memory can be divided up fairly.
+ *
+ * The access_virt_array routines are responsible for making a specific strip
+ * area accessible (after reading or writing the backing file, if necessary).
+ * Note that the access routines are told whether the caller intends to modify
+ * the accessed strip; during a read-only pass this saves having to rewrite
+ * data to disk. The access routines are also responsible for pre-zeroing
+ * any newly accessed rows, if pre-zeroing was requested.
+ *
+ * In current usage, the access requests are usually for nonoverlapping
+ * strips; that is, successive access start_row numbers differ by exactly
+ * num_rows = maxaccess. This means we can get good performance with simple
+ * buffer dump/reload logic, by making the in-memory buffer be a multiple
+ * of the access height; then there will never be accesses across bufferload
+ * boundaries. The code will still work with overlapping access requests,
+ * but it doesn't handle bufferload overlaps very efficiently.
+ */
+
+
+METHODDEF(jvirt_sarray_ptr)
+request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
+ JDIMENSION samplesperrow, JDIMENSION numrows,
+ JDIMENSION maxaccess)
+/* Request a virtual 2-D sample array */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ jvirt_sarray_ptr result;
+
+ /* Only IMAGE-lifetime virtual arrays are currently supported */
+ if (pool_id != JPOOL_IMAGE)
+ ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
+
+ /* get control block */
+ result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
+ SIZEOF(struct jvirt_sarray_control));
+
+ result->mem_buffer = NULL; /* marks array not yet realized */
+ result->rows_in_array = numrows;
+ result->samplesperrow = samplesperrow;
+ result->maxaccess = maxaccess;
+ result->pre_zero = pre_zero;
+ result->b_s_open = FALSE; /* no associated backing-store object */
+ result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
+ mem->virt_sarray_list = result;
+
+ return result;
+}
+
+
+METHODDEF(jvirt_barray_ptr)
+request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
+ JDIMENSION blocksperrow, JDIMENSION numrows,
+ JDIMENSION maxaccess)
+/* Request a virtual 2-D coefficient-block array */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ jvirt_barray_ptr result;
+
+ /* Only IMAGE-lifetime virtual arrays are currently supported */
+ if (pool_id != JPOOL_IMAGE)
+ ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
+
+ /* get control block */
+ result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
+ SIZEOF(struct jvirt_barray_control));
+
+ result->mem_buffer = NULL; /* marks array not yet realized */
+ result->rows_in_array = numrows;
+ result->blocksperrow = blocksperrow;
+ result->maxaccess = maxaccess;
+ result->pre_zero = pre_zero;
+ result->b_s_open = FALSE; /* no associated backing-store object */
+ result->next = mem->virt_barray_list; /* add to list of virtual arrays */
+ mem->virt_barray_list = result;
+
+ return result;
+}
+
+
+METHODDEF(void)
+realize_virt_arrays (j_common_ptr cinfo)
+/* Allocate the in-memory buffers for any unrealized virtual arrays */
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ long space_per_minheight, maximum_space, avail_mem;
+ long minheights, max_minheights;
+ jvirt_sarray_ptr sptr;
+ jvirt_barray_ptr bptr;
+
+ /* Compute the minimum space needed (maxaccess rows in each buffer)
+ * and the maximum space needed (full image height in each buffer).
+ * These may be of use to the system-dependent jpeg_mem_available routine.
+ */
+ space_per_minheight = 0;
+ maximum_space = 0;
+ for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
+ if (sptr->mem_buffer == NULL) { /* if not realized yet */
+ space_per_minheight += (long) sptr->maxaccess *
+ (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
+ maximum_space += (long) sptr->rows_in_array *
+ (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
+ }
+ }
+ for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
+ if (bptr->mem_buffer == NULL) { /* if not realized yet */
+ space_per_minheight += (long) bptr->maxaccess *
+ (long) bptr->blocksperrow * SIZEOF(JBLOCK);
+ maximum_space += (long) bptr->rows_in_array *
+ (long) bptr->blocksperrow * SIZEOF(JBLOCK);
+ }
+ }
+
+ if (space_per_minheight <= 0)
+ return; /* no unrealized arrays, no work */
+
+ /* Determine amount of memory to actually use; this is system-dependent. */
+ avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space,
+ mem->total_space_allocated);
+
+ /* If the maximum space needed is available, make all the buffers full
+ * height; otherwise parcel it out with the same number of minheights
+ * in each buffer.
+ */
+ if (avail_mem >= maximum_space)
+ max_minheights = 1000000000L;
+ else {
+ max_minheights = avail_mem / space_per_minheight;
+ /* If there doesn't seem to be enough space, try to get the minimum
+ * anyway. This allows a "stub" implementation of jpeg_mem_available().
+ */
+ if (max_minheights <= 0)
+ max_minheights = 1;
+ }
+
+ /* Allocate the in-memory buffers and initialize backing store as needed. */
+
+ for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
+ if (sptr->mem_buffer == NULL) { /* if not realized yet */
+ minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L;
+ if (minheights <= max_minheights) {
+ /* This buffer fits in memory */
+ sptr->rows_in_mem = sptr->rows_in_array;
+ } else {
+ /* It doesn't fit in memory, create backing store. */
+ sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess);
+ jpeg_open_backing_store(cinfo, & sptr->b_s_info,
+ (long) sptr->rows_in_array *
+ (long) sptr->samplesperrow *
+ (long) SIZEOF(JSAMPLE));
+ sptr->b_s_open = TRUE;
+ }
+ sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
+ sptr->samplesperrow, sptr->rows_in_mem);
+ sptr->rowsperchunk = mem->last_rowsperchunk;
+ sptr->cur_start_row = 0;
+ sptr->first_undef_row = 0;
+ sptr->dirty = FALSE;
+ }
+ }
+
+ for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
+ if (bptr->mem_buffer == NULL) { /* if not realized yet */
+ minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
+ if (minheights <= max_minheights) {
+ /* This buffer fits in memory */
+ bptr->rows_in_mem = bptr->rows_in_array;
+ } else {
+ /* It doesn't fit in memory, create backing store. */
+ bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess);
+ jpeg_open_backing_store(cinfo, & bptr->b_s_info,
+ (long) bptr->rows_in_array *
+ (long) bptr->blocksperrow *
+ (long) SIZEOF(JBLOCK));
+ bptr->b_s_open = TRUE;
+ }
+ bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
+ bptr->blocksperrow, bptr->rows_in_mem);
+ bptr->rowsperchunk = mem->last_rowsperchunk;
+ bptr->cur_start_row = 0;
+ bptr->first_undef_row = 0;
+ bptr->dirty = FALSE;
+ }
+ }
+}
+
+
+LOCAL(void)
+do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
+/* Do backing store read or write of a virtual sample array */
+{
+ long bytesperrow, file_offset, byte_count, rows, thisrow, i;
+
+ bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
+ file_offset = ptr->cur_start_row * bytesperrow;
+ /* Loop to read or write each allocation chunk in mem_buffer */
+ for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
+ /* One chunk, but check for short chunk at end of buffer */
+ rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
+ /* Transfer no more than is currently defined */
+ thisrow = (long) ptr->cur_start_row + i;
+ rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
+ /* Transfer no more than fits in file */
+ rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
+ if (rows <= 0) /* this chunk might be past end of file! */
+ break;
+ byte_count = rows * bytesperrow;
+ if (writing)
+ (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
+ (void FAR *) ptr->mem_buffer[i],
+ file_offset, byte_count);
+ else
+ (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
+ (void FAR *) ptr->mem_buffer[i],
+ file_offset, byte_count);
+ file_offset += byte_count;
+ }
+}
+
+
+LOCAL(void)
+do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
+/* Do backing store read or write of a virtual coefficient-block array */
+{
+ long bytesperrow, file_offset, byte_count, rows, thisrow, i;
+
+ bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
+ file_offset = ptr->cur_start_row * bytesperrow;
+ /* Loop to read or write each allocation chunk in mem_buffer */
+ for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
+ /* One chunk, but check for short chunk at end of buffer */
+ rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
+ /* Transfer no more than is currently defined */
+ thisrow = (long) ptr->cur_start_row + i;
+ rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
+ /* Transfer no more than fits in file */
+ rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
+ if (rows <= 0) /* this chunk might be past end of file! */
+ break;
+ byte_count = rows * bytesperrow;
+ if (writing)
+ (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
+ (void FAR *) ptr->mem_buffer[i],
+ file_offset, byte_count);
+ else
+ (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
+ (void FAR *) ptr->mem_buffer[i],
+ file_offset, byte_count);
+ file_offset += byte_count;
+ }
+}
+
+
+METHODDEF(JSAMPARRAY)
+access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
+ JDIMENSION start_row, JDIMENSION num_rows,
+ boolean writable)
+/* Access the part of a virtual sample array starting at start_row */
+/* and extending for num_rows rows. writable is true if */
+/* caller intends to modify the accessed area. */
+{
+ JDIMENSION end_row = start_row + num_rows;
+ JDIMENSION undef_row;
+
+ /* debugging check */
+ if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
+ ptr->mem_buffer == NULL)
+ ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
+
+ /* Make the desired part of the virtual array accessible */
+ if (start_row < ptr->cur_start_row ||
+ end_row > ptr->cur_start_row+ptr->rows_in_mem) {
+ if (! ptr->b_s_open)
+ ERREXIT(cinfo, JERR_VIRTUAL_BUG);
+ /* Flush old buffer contents if necessary */
+ if (ptr->dirty) {
+ do_sarray_io(cinfo, ptr, TRUE);
+ ptr->dirty = FALSE;
+ }
+ /* Decide what part of virtual array to access.
+ * Algorithm: if target address > current window, assume forward scan,
+ * load starting at target address. If target address < current window,
+ * assume backward scan, load so that target area is top of window.
+ * Note that when switching from forward write to forward read, will have
+ * start_row = 0, so the limiting case applies and we load from 0 anyway.
+ */
+ if (start_row > ptr->cur_start_row) {
+ ptr->cur_start_row = start_row;
+ } else {
+ /* use long arithmetic here to avoid overflow & unsigned problems */
+ long ltemp;
+
+ ltemp = (long) end_row - (long) ptr->rows_in_mem;
+ if (ltemp < 0)
+ ltemp = 0; /* don't fall off front end of file */
+ ptr->cur_start_row = (JDIMENSION) ltemp;
+ }
+ /* Read in the selected part of the array.
+ * During the initial write pass, we will do no actual read
+ * because the selected part is all undefined.
+ */
+ do_sarray_io(cinfo, ptr, FALSE);
+ }
+ /* Ensure the accessed part of the array is defined; prezero if needed.
+ * To improve locality of access, we only prezero the part of the array
+ * that the caller is about to access, not the entire in-memory array.
+ */
+ if (ptr->first_undef_row < end_row) {
+ if (ptr->first_undef_row < start_row) {
+ if (writable) /* writer skipped over a section of array */
+ ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
+ undef_row = start_row; /* but reader is allowed to read ahead */
+ } else {
+ undef_row = ptr->first_undef_row;
+ }
+ if (writable)
+ ptr->first_undef_row = end_row;
+ if (ptr->pre_zero) {
+ size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
+ undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
+ end_row -= ptr->cur_start_row;
+ while (undef_row < end_row) {
+ jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
+ undef_row++;
+ }
+ } else {
+ if (! writable) /* reader looking at undefined data */
+ ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
+ }
+ }
+ /* Flag the buffer dirty if caller will write in it */
+ if (writable)
+ ptr->dirty = TRUE;
+ /* Return address of proper part of the buffer */
+ return ptr->mem_buffer + (start_row - ptr->cur_start_row);
+}
+
+
+METHODDEF(JBLOCKARRAY)
+access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
+ JDIMENSION start_row, JDIMENSION num_rows,
+ boolean writable)
+/* Access the part of a virtual block array starting at start_row */
+/* and extending for num_rows rows. writable is true if */
+/* caller intends to modify the accessed area. */
+{
+ JDIMENSION end_row = start_row + num_rows;
+ JDIMENSION undef_row;
+
+ /* debugging check */
+ if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
+ ptr->mem_buffer == NULL)
+ ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
+
+ /* Make the desired part of the virtual array accessible */
+ if (start_row < ptr->cur_start_row ||
+ end_row > ptr->cur_start_row+ptr->rows_in_mem) {
+ if (! ptr->b_s_open)
+ ERREXIT(cinfo, JERR_VIRTUAL_BUG);
+ /* Flush old buffer contents if necessary */
+ if (ptr->dirty) {
+ do_barray_io(cinfo, ptr, TRUE);
+ ptr->dirty = FALSE;
+ }
+ /* Decide what part of virtual array to access.
+ * Algorithm: if target address > current window, assume forward scan,
+ * load starting at target address. If target address < current window,
+ * assume backward scan, load so that target area is top of window.
+ * Note that when switching from forward write to forward read, will have
+ * start_row = 0, so the limiting case applies and we load from 0 anyway.
+ */
+ if (start_row > ptr->cur_start_row) {
+ ptr->cur_start_row = start_row;
+ } else {
+ /* use long arithmetic here to avoid overflow & unsigned problems */
+ long ltemp;
+
+ ltemp = (long) end_row - (long) ptr->rows_in_mem;
+ if (ltemp < 0)
+ ltemp = 0; /* don't fall off front end of file */
+ ptr->cur_start_row = (JDIMENSION) ltemp;
+ }
+ /* Read in the selected part of the array.
+ * During the initial write pass, we will do no actual read
+ * because the selected part is all undefined.
+ */
+ do_barray_io(cinfo, ptr, FALSE);
+ }
+ /* Ensure the accessed part of the array is defined; prezero if needed.
+ * To improve locality of access, we only prezero the part of the array
+ * that the caller is about to access, not the entire in-memory array.
+ */
+ if (ptr->first_undef_row < end_row) {
+ if (ptr->first_undef_row < start_row) {
+ if (writable) /* writer skipped over a section of array */
+ ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
+ undef_row = start_row; /* but reader is allowed to read ahead */
+ } else {
+ undef_row = ptr->first_undef_row;
+ }
+ if (writable)
+ ptr->first_undef_row = end_row;
+ if (ptr->pre_zero) {
+ size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
+ undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
+ end_row -= ptr->cur_start_row;
+ while (undef_row < end_row) {
+ jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
+ undef_row++;
+ }
+ } else {
+ if (! writable) /* reader looking at undefined data */
+ ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
+ }
+ }
+ /* Flag the buffer dirty if caller will write in it */
+ if (writable)
+ ptr->dirty = TRUE;
+ /* Return address of proper part of the buffer */
+ return ptr->mem_buffer + (start_row - ptr->cur_start_row);
+}
+
+
+/*
+ * Release all objects belonging to a specified pool.
+ */
+
+METHODDEF(void)
+free_pool (j_common_ptr cinfo, int pool_id)
+{
+ my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
+ small_pool_ptr shdr_ptr;
+ large_pool_ptr lhdr_ptr;
+ size_t space_freed;
+
+ if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
+ ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
+
+#ifdef MEM_STATS
+ if (cinfo->err->trace_level > 1)
+ print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
+#endif
+
+ /* If freeing IMAGE pool, close any virtual arrays first */
+ if (pool_id == JPOOL_IMAGE) {
+ jvirt_sarray_ptr sptr;
+ jvirt_barray_ptr bptr;
+
+ for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
+ if (sptr->b_s_open) { /* there may be no backing store */
+ sptr->b_s_open = FALSE; /* prevent recursive close if error */
+ (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
+ }
+ }
+ mem->virt_sarray_list = NULL;
+ for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
+ if (bptr->b_s_open) { /* there may be no backing store */
+ bptr->b_s_open = FALSE; /* prevent recursive close if error */
+ (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
+ }
+ }
+ mem->virt_barray_list = NULL;
+ }
+
+ /* Release large objects */
+ lhdr_ptr = mem->large_list[pool_id];
+ mem->large_list[pool_id] = NULL;
+
+ while (lhdr_ptr != NULL) {
+ large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
+ space_freed = lhdr_ptr->hdr.bytes_used +
+ lhdr_ptr->hdr.bytes_left +
+ SIZEOF(large_pool_hdr);
+ jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
+ mem->total_space_allocated -= space_freed;
+ lhdr_ptr = next_lhdr_ptr;
+ }
+
+ /* Release small objects */
+ shdr_ptr = mem->small_list[pool_id];
+ mem->small_list[pool_id] = NULL;
+
+ while (shdr_ptr != NULL) {
+ small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
+ space_freed = shdr_ptr->hdr.bytes_used +
+ shdr_ptr->hdr.bytes_left +
+ SIZEOF(small_pool_hdr);
+ jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
+ mem->total_space_allocated -= space_freed;
+ shdr_ptr = next_shdr_ptr;
+ }
+}
+
+
+/*
+ * Close up shop entirely.
+ * Note that this cannot be called unless cinfo->mem is non-NULL.
+ */
+
+METHODDEF(void)
+self_destruct (j_common_ptr cinfo)
+{
+ int pool;
+
+ /* Close all backing store, release all memory.
+ * Releasing pools in reverse order might help avoid fragmentation
+ * with some (brain-damaged) malloc libraries.
+ */
+ for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
+ free_pool(cinfo, pool);
+ }
+
+ /* Release the memory manager control block too. */
+ jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
+ cinfo->mem = NULL; /* ensures I will be called only once */
+
+ jpeg_mem_term(cinfo); /* system-dependent cleanup */
+}
+
+
+/*
+ * Memory manager initialization.
+ * When this is called, only the error manager pointer is valid in cinfo!
+ */
+
+GLOBAL(void)
+jinit_memory_mgr (j_common_ptr cinfo)
+{
+ my_mem_ptr mem;
+ long max_to_use;
+ int pool;
+ size_t test_mac;
+
+ cinfo->mem = NULL; /* for safety if init fails */
+
+ /* Check for configuration errors.
+ * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
+ * doesn't reflect any real hardware alignment requirement.
+ * The test is a little tricky: for X>0, X and X-1 have no one-bits
+ * in common if and only if X is a power of 2, ie has only one one-bit.
+ * Some compilers may give an "unreachable code" warning here; ignore it.
+ */
+ if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
+ ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
+ /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
+ * a multiple of SIZEOF(ALIGN_TYPE).
+ * Again, an "unreachable code" warning may be ignored here.
+ * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
+ */
+ test_mac = (size_t) MAX_ALLOC_CHUNK;
+ if ((long) test_mac != MAX_ALLOC_CHUNK ||
+ (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
+ ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
+
+ max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
+
+ /* Attempt to allocate memory manager's control block */
+ mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
+
+ if (mem == NULL) {
+ jpeg_mem_term(cinfo); /* system-dependent cleanup */
+ ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
+ }
+
+ /* OK, fill in the method pointers */
+ mem->pub.alloc_small = alloc_small;
+ mem->pub.alloc_large = alloc_large;
+ mem->pub.alloc_sarray = alloc_sarray;
+ mem->pub.alloc_barray = alloc_barray;
+#ifdef NEED_DARRAY
+ mem->pub.alloc_darray = alloc_darray;
+#endif
+ mem->pub.request_virt_sarray = request_virt_sarray;
+ mem->pub.request_virt_barray = request_virt_barray;
+ mem->pub.realize_virt_arrays = realize_virt_arrays;
+ mem->pub.access_virt_sarray = access_virt_sarray;
+ mem->pub.access_virt_barray = access_virt_barray;
+ mem->pub.free_pool = free_pool;
+ mem->pub.self_destruct = self_destruct;
+
+ /* Make MAX_ALLOC_CHUNK accessible to other modules */
+ mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
+
+ /* Initialize working state */
+ mem->pub.max_memory_to_use = max_to_use;
+
+ for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
+ mem->small_list[pool] = NULL;
+ mem->large_list[pool] = NULL;
+ }
+ mem->virt_sarray_list = NULL;
+ mem->virt_barray_list = NULL;
+
+ mem->total_space_allocated = SIZEOF(my_memory_mgr);
+
+ /* Declare ourselves open for business */
+ cinfo->mem = & mem->pub;
+
+ /* Check for an environment variable JPEGMEM; if found, override the
+ * default max_memory setting from jpeg_mem_init. Note that the
+ * surrounding application may again override this value.
+ * If your system doesn't support getenv(), define NO_GETENV to disable
+ * this feature.
+ */
+#ifndef NO_GETENV
+ { char * memenv;
+
+ if ((memenv = getenv("JPEGMEM")) != NULL) {
+ char ch = 'x';
+
+ if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
+ if (ch == 'm' || ch == 'M')
+ max_to_use *= 1000L;
+ mem->pub.max_memory_to_use = max_to_use * 1000L;
+ }
+ }
+ }
+#endif
+
+}
--- /dev/null
+/*
+ * jmemnobs.c
+ *
+ * Copyright (C) 1992-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file provides a really simple implementation of the system-
+ * dependent portion of the JPEG memory manager. This implementation
+ * assumes that no backing-store files are needed: all required space
+ * can be obtained from malloc().
+ * This is very portable in the sense that it'll compile on almost anything,
+ * but you'd better have lots of main memory (or virtual memory) if you want
+ * to process big images.
+ * Note that the max_memory_to_use option is ignored by this implementation.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jmemsys.h" /* import the system-dependent declarations */
+
+#ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc(),free() */
+extern void * malloc JPP((size_t size));
+extern void free JPP((void *ptr));
+#endif
+
+
+/*
+ * Memory allocation and freeing are controlled by the regular library
+ * routines malloc() and free().
+ */
+
+GLOBAL(void *)
+jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
+{
+ (void)cinfo;
+ return (void *) malloc(sizeofobject);
+}
+
+GLOBAL(void)
+jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject)
+{
+ (void)cinfo;(void)sizeofobject;
+ free(object);
+}
+
+
+/*
+ * "Large" objects are treated the same as "small" ones.
+ * NB: although we include FAR keywords in the routine declarations,
+ * this file won't actually work in 80x86 small/medium model; at least,
+ * you probably won't be able to process useful-size images in only 64KB.
+ */
+
+GLOBAL(void FAR *)
+jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
+{
+ (void)cinfo;
+ return (void FAR *) malloc(sizeofobject);
+}
+
+GLOBAL(void)
+jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)
+{
+ (void)cinfo;(void)sizeofobject;
+ free(object);
+}
+
+
+/*
+ * This routine computes the total memory space available for allocation.
+ * Here we always say, "we got all you want bud!"
+ */
+
+GLOBAL(long)
+jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
+ long max_bytes_needed, long already_allocated)
+{
+ (void)cinfo;(void)min_bytes_needed;(void)already_allocated;
+ return max_bytes_needed;
+}
+
+
+/*
+ * Backing store (temporary file) management.
+ * Since jpeg_mem_available always promised the moon,
+ * this should never be called and we can just error out.
+ */
+
+GLOBAL(void)
+jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
+ long total_bytes_needed)
+{
+ (void)info;(void)total_bytes_needed;
+ ERREXIT(cinfo, JERR_NO_BACKING_STORE);
+}
+
+
+/*
+ * These routines take care of any system-dependent initialization and
+ * cleanup required. Here, there isn't any.
+ */
+
+GLOBAL(long)
+jpeg_mem_init (j_common_ptr cinfo)
+{
+ (void)cinfo;
+ return 0; /* just set max_memory_to_use to 0 */
+}
+
+GLOBAL(void)
+jpeg_mem_term (j_common_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work */
+}
--- /dev/null
+/*
+ * jmemsys.h
+ *
+ * Copyright (C) 1992-1997, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This include file defines the interface between the system-independent
+ * and system-dependent portions of the JPEG memory manager. No other
+ * modules need include it. (The system-independent portion is jmemmgr.c;
+ * there are several different versions of the system-dependent portion.)
+ *
+ * This file works as-is for the system-dependent memory managers supplied
+ * in the IJG distribution. You may need to modify it if you write a
+ * custom memory manager. If system-dependent changes are needed in
+ * this file, the best method is to #ifdef them based on a configuration
+ * symbol supplied in jconfig.h, as we have done with USE_MSDOS_MEMMGR
+ * and USE_MAC_MEMMGR.
+ */
+
+
+/* Short forms of external names for systems with brain-damaged linkers. */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_get_small jGetSmall
+#define jpeg_free_small jFreeSmall
+#define jpeg_get_large jGetLarge
+#define jpeg_free_large jFreeLarge
+#define jpeg_mem_available jMemAvail
+#define jpeg_open_backing_store jOpenBackStore
+#define jpeg_mem_init jMemInit
+#define jpeg_mem_term jMemTerm
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+
+/*
+ * These two functions are used to allocate and release small chunks of
+ * memory. (Typically the total amount requested through jpeg_get_small is
+ * no more than 20K or so; this will be requested in chunks of a few K each.)
+ * Behavior should be the same as for the standard library functions malloc
+ * and free; in particular, jpeg_get_small must return NULL on failure.
+ * On most systems, these ARE malloc and free. jpeg_free_small is passed the
+ * size of the object being freed, just in case it's needed.
+ * On an 80x86 machine using small-data memory model, these manage near heap.
+ */
+
+EXTERN(void *) jpeg_get_small JPP((j_common_ptr cinfo, size_t sizeofobject));
+EXTERN(void) jpeg_free_small JPP((j_common_ptr cinfo, void * object,
+ size_t sizeofobject));
+
+/*
+ * These two functions are used to allocate and release large chunks of
+ * memory (up to the total free space designated by jpeg_mem_available).
+ * The interface is the same as above, except that on an 80x86 machine,
+ * far pointers are used. On most other machines these are identical to
+ * the jpeg_get/free_small routines; but we keep them separate anyway,
+ * in case a different allocation strategy is desirable for large chunks.
+ */
+
+EXTERN(void FAR *) jpeg_get_large JPP((j_common_ptr cinfo,
+ size_t sizeofobject));
+EXTERN(void) jpeg_free_large JPP((j_common_ptr cinfo, void FAR * object,
+ size_t sizeofobject));
+
+/*
+ * The macro MAX_ALLOC_CHUNK designates the maximum number of bytes that may
+ * be requested in a single call to jpeg_get_large (and jpeg_get_small for that
+ * matter, but that case should never come into play). This macro is needed
+ * to model the 64Kb-segment-size limit of far addressing on 80x86 machines.
+ * On those machines, we expect that jconfig.h will provide a proper value.
+ * On machines with 32-bit flat address spaces, any large constant may be used.
+ *
+ * NB: jmemmgr.c expects that MAX_ALLOC_CHUNK will be representable as type
+ * size_t and will be a multiple of sizeof(align_type).
+ */
+
+#ifndef MAX_ALLOC_CHUNK /* may be overridden in jconfig.h */
+#define MAX_ALLOC_CHUNK 1000000000L
+#endif
+
+/*
+ * This routine computes the total space still available for allocation by
+ * jpeg_get_large. If more space than this is needed, backing store will be
+ * used. NOTE: any memory already allocated must not be counted.
+ *
+ * There is a minimum space requirement, corresponding to the minimum
+ * feasible buffer sizes; jmemmgr.c will request that much space even if
+ * jpeg_mem_available returns zero. The maximum space needed, enough to hold
+ * all working storage in memory, is also passed in case it is useful.
+ * Finally, the total space already allocated is passed. If no better
+ * method is available, cinfo->mem->max_memory_to_use - already_allocated
+ * is often a suitable calculation.
+ *
+ * It is OK for jpeg_mem_available to underestimate the space available
+ * (that'll just lead to more backing-store access than is really necessary).
+ * However, an overestimate will lead to failure. Hence it's wise to subtract
+ * a slop factor from the true available space. 5% should be enough.
+ *
+ * On machines with lots of virtual memory, any large constant may be returned.
+ * Conversely, zero may be returned to always use the minimum amount of memory.
+ */
+
+EXTERN(long) jpeg_mem_available JPP((j_common_ptr cinfo,
+ long min_bytes_needed,
+ long max_bytes_needed,
+ long already_allocated));
+
+
+/*
+ * This structure holds whatever state is needed to access a single
+ * backing-store object. The read/write/close method pointers are called
+ * by jmemmgr.c to manipulate the backing-store object; all other fields
+ * are private to the system-dependent backing store routines.
+ */
+
+#define TEMP_NAME_LENGTH 64 /* max length of a temporary file's name */
+
+
+#ifdef USE_MSDOS_MEMMGR /* DOS-specific junk */
+
+typedef unsigned short XMSH; /* type of extended-memory handles */
+typedef unsigned short EMSH; /* type of expanded-memory handles */
+
+typedef union {
+ short file_handle; /* DOS file handle if it's a temp file */
+ XMSH xms_handle; /* handle if it's a chunk of XMS */
+ EMSH ems_handle; /* handle if it's a chunk of EMS */
+} handle_union;
+
+#endif /* USE_MSDOS_MEMMGR */
+
+#ifdef USE_MAC_MEMMGR /* Mac-specific junk */
+#include <Files.h>
+#endif /* USE_MAC_MEMMGR */
+
+
+typedef struct backing_store_struct * backing_store_ptr;
+
+typedef struct backing_store_struct {
+ /* Methods for reading/writing/closing this backing-store object */
+ JMETHOD(void, read_backing_store, (j_common_ptr cinfo,
+ backing_store_ptr info,
+ void FAR * buffer_address,
+ long file_offset, long byte_count));
+ JMETHOD(void, write_backing_store, (j_common_ptr cinfo,
+ backing_store_ptr info,
+ void FAR * buffer_address,
+ long file_offset, long byte_count));
+ JMETHOD(void, close_backing_store, (j_common_ptr cinfo,
+ backing_store_ptr info));
+
+ /* Private fields for system-dependent backing-store management */
+#ifdef USE_MSDOS_MEMMGR
+ /* For the MS-DOS manager (jmemdos.c), we need: */
+ handle_union handle; /* reference to backing-store storage object */
+ char temp_name[TEMP_NAME_LENGTH]; /* name if it's a file */
+#else
+#ifdef USE_MAC_MEMMGR
+ /* For the Mac manager (jmemmac.c), we need: */
+ short temp_file; /* file reference number to temp file */
+ FSSpec tempSpec; /* the FSSpec for the temp file */
+ char temp_name[TEMP_NAME_LENGTH]; /* name if it's a file */
+#else
+ /* For a typical implementation with temp files, we need: */
+ FILE * temp_file; /* stdio reference to temp file */
+ char temp_name[TEMP_NAME_LENGTH]; /* name of temp file */
+#endif
+#endif
+} backing_store_info;
+
+
+/*
+ * Initial opening of a backing-store object. This must fill in the
+ * read/write/close pointers in the object. The read/write routines
+ * may take an error exit if the specified maximum file size is exceeded.
+ * (If jpeg_mem_available always returns a large value, this routine can
+ * just take an error exit.)
+ */
+
+EXTERN(void) jpeg_open_backing_store JPP((j_common_ptr cinfo,
+ backing_store_ptr info,
+ long total_bytes_needed));
+
+
+/*
+ * These routines take care of any system-dependent initialization and
+ * cleanup required. jpeg_mem_init will be called before anything is
+ * allocated (and, therefore, nothing in cinfo is of use except the error
+ * manager pointer). It should return a suitable default value for
+ * max_memory_to_use; this may subsequently be overridden by the surrounding
+ * application. (Note that max_memory_to_use is only important if
+ * jpeg_mem_available chooses to consult it ... no one else will.)
+ * jpeg_mem_term may assume that all requested memory has been freed and that
+ * all opened backing-store objects have been closed.
+ */
+
+EXTERN(long) jpeg_mem_init JPP((j_common_ptr cinfo));
+EXTERN(void) jpeg_mem_term JPP((j_common_ptr cinfo));
--- /dev/null
+/*
+ * jmorecfg.h
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains additional configuration options that customize the
+ * JPEG software for special applications or support machine-dependent
+ * optimizations. Most users will not need to touch this file.
+ */
+
+/*
+ * Define BITS_IN_JSAMPLE as either
+ * 8 for 8-bit sample values (the usual setting)
+ * 12 for 12-bit sample values
+ * Only 8 and 12 are legal data precisions for lossy JPEG according to the
+ * JPEG standard, and the IJG code does not support anything else!
+ * We do not support run-time selection of data precision, sorry.
+ */
+
+/*#define BITS_IN_JSAMPLE 8*//* use 8 or 12 (or 16 only for lossless) */
+#define BITS_IN_JSAMPLE @CMAKE_BITS_IN_JSAMPLE@
+
+/*
+ * Maximum number of components (color channels) allowed in JPEG image.
+ * To meet the letter of the JPEG spec, set this to 255. However, darn
+ * few applications need more than 4 channels (maybe 5 for CMYK + alpha
+ * mask). We recommend 10 as a reasonable compromise; use 4 if you are
+ * really short on memory. (Each allowed component costs a hundred or so
+ * bytes of storage, whether actually used in an image or not.)
+ */
+
+#define MAX_COMPONENTS 10 /* maximum number of image components */
+
+
+/*
+ * Basic data types.
+ * You may need to change these if you have a machine with unusual data
+ * type sizes; for example, "char" not 8 bits, "short" not 16 bits,
+ * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits,
+ * but it had better be at least 16.
+ */
+
+/* Representation of a single sample (pixel element value).
+ * We frequently allocate large arrays of these, so it's important to keep
+ * them small. But if you have memory to burn and access to char or short
+ * arrays is very slow on your hardware, you might want to change these.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+/* JSAMPLE should be the smallest type that will hold the values 0..255.
+ * You can use a signed char by having GETJSAMPLE mask it with 0xFF.
+ */
+
+#ifdef HAVE_UNSIGNED_CHAR
+
+typedef unsigned char JSAMPLE;
+#define GETJSAMPLE(value) ((int) (value))
+
+#else /* not HAVE_UNSIGNED_CHAR */
+
+typedef char JSAMPLE;
+#ifdef CHAR_IS_UNSIGNED
+#define GETJSAMPLE(value) ((int) (value))
+#else
+#define GETJSAMPLE(value) ((int) (value) & 0xFF)
+#endif /* CHAR_IS_UNSIGNED */
+
+#endif /* HAVE_UNSIGNED_CHAR */
+
+#define MAXJSAMPLE 255
+#define CENTERJSAMPLE 128
+
+#endif /* BITS_IN_JSAMPLE == 8 */
+
+
+#if BITS_IN_JSAMPLE == 12
+/* JSAMPLE should be the smallest type that will hold the values 0..4095.
+ * On nearly all machines "short" will do nicely.
+ */
+
+typedef short JSAMPLE;
+#define GETJSAMPLE(value) ((int) (value))
+
+#define MAXJSAMPLE 4095
+#define CENTERJSAMPLE 2048
+
+#endif /* BITS_IN_JSAMPLE == 12 */
+
+
+#if BITS_IN_JSAMPLE == 16
+/* JSAMPLE should be the smallest type that will hold the values 0..65535.
+ * You can use a signed short by having GETJSAMPLE mask it with 0xFFFF.
+ */
+
+#ifdef HAVE_UNSIGNED_SHORT
+
+typedef unsigned short JSAMPLE;
+#define GETJSAMPLE(value) ((int) (value))
+
+#else /* not HAVE_UNSIGNED_SHORT */
+
+typedef short JSAMPLE;
+#ifdef SHORT_IS_UNSIGNED
+#define GETJSAMPLE(value) ((int) (value))
+#else
+#define GETJSAMPLE(value) ((int) (value) & 0xFFFF)
+#endif /* SHORT_IS_UNSIGNED */
+
+#endif /* HAVE_UNSIGNED_SHORT */
+
+#define MAXJSAMPLE 65535
+#define CENTERJSAMPLE 32768
+
+#endif /* BITS_IN_JSAMPLE == 16 */
+
+
+/* Representation of a DCT frequency coefficient.
+ * This should be a signed value of at least 16 bits; "short" is usually OK.
+ * Again, we allocate large arrays of these, but you can change to int
+ * if you have memory to burn and "short" is really slow.
+ */
+
+typedef short JCOEF;
+
+
+/* Representation of a spatial difference value.
+ * This should be a signed value of at least 16 bits; int is usually OK.
+ */
+
+typedef int JDIFF;
+
+
+/* Compressed datastreams are represented as arrays of JOCTET.
+ * These must be EXACTLY 8 bits wide, at least once they are written to
+ * external storage. Note that when using the stdio data source/destination
+ * managers, this is also the data type passed to fread/fwrite.
+ */
+
+#ifdef HAVE_UNSIGNED_CHAR
+
+typedef unsigned char JOCTET;
+#define GETJOCTET(value) (value)
+
+#else /* not HAVE_UNSIGNED_CHAR */
+
+typedef char JOCTET;
+#ifdef CHAR_IS_UNSIGNED
+#define GETJOCTET(value) (value)
+#else
+#define GETJOCTET(value) ((value) & 0xFF)
+#endif /* CHAR_IS_UNSIGNED */
+
+#endif /* HAVE_UNSIGNED_CHAR */
+
+
+/* These typedefs are used for various table entries and so forth.
+ * They must be at least as wide as specified; but making them too big
+ * won't cost a huge amount of memory, so we don't provide special
+ * extraction code like we did for JSAMPLE. (In other words, these
+ * typedefs live at a different point on the speed/space tradeoff curve.)
+ */
+
+/* UINT8 must hold at least the values 0..255. */
+
+#ifdef HAVE_UNSIGNED_CHAR
+typedef unsigned char UINT8;
+#else /* not HAVE_UNSIGNED_CHAR */
+#ifdef CHAR_IS_UNSIGNED
+typedef char UINT8;
+#else /* not CHAR_IS_UNSIGNED */
+typedef short UINT8;
+#endif /* CHAR_IS_UNSIGNED */
+#endif /* HAVE_UNSIGNED_CHAR */
+
+/* UINT16 must hold at least the values 0..65535. */
+
+#ifdef HAVE_UNSIGNED_SHORT
+typedef unsigned short UINT16;
+#else /* not HAVE_UNSIGNED_SHORT */
+typedef unsigned int UINT16;
+#endif /* HAVE_UNSIGNED_SHORT */
+
+/* INT16 must hold at least the values -32768..32767. */
+
+#ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
+typedef short INT16;
+#endif
+
+/* INT32 must hold at least signed 32-bit values. */
+/* X11/xmd.h and basetsd.h correctly defines INT32 */
+
+#if !defined(XMD_H) && !defined(_BASETSD_H_)
+typedef int INT32;
+#endif
+
+/* Datatype used for image dimensions. The JPEG standard only supports
+ * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
+ * "unsigned int" is sufficient on all machines. However, if you need to
+ * handle larger images and you don't mind deviating from the spec, you
+ * can change this datatype.
+ */
+
+typedef unsigned int JDIMENSION;
+
+#define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
+
+
+/* These macros are used in all function definitions and extern declarations.
+ * You could modify them if you need to change function linkage conventions;
+ * in particular, you'll need to do that to make the library a Windows DLL.
+ * Another application is to make all functions global for use with debuggers
+ * or code profilers that require it.
+ */
+
+/* a function called through method pointers: */
+#define METHODDEF(type) static type
+/* a function used only in its module: */
+#define LOCAL(type) static type
+/* a function referenced thru EXTERNs: */
+#if defined( _WIN32 ) && defined (JPEGDLL)
+#define GLOBAL(type) __declspec(dllexport) type
+#else
+#define GLOBAL(type) type
+#endif
+
+/* a reference to a GLOBAL function: */
+#if defined(_WIN32) && !defined(JPEGSTATIC)
+#ifdef JPEGDLL
+/* Win32, building a dll */
+#define EXTERN(type) __declspec(dllexport) type
+#else
+/* Win32, not building a dll but using the dll */
+#define EXTERN(type) __declspec(dllimport) type
+#endif
+#else
+/* not a Win32 system or building a static Win32 lib */
+#define EXTERN(type) extern type
+#endif
+
+
+/* This macro is used to declare a "method", that is, a function pointer.
+ * We want to supply prototype parameters if the compiler can cope.
+ * Note that the arglist parameter must be parenthesized!
+ * Again, you can customize this if you need special linkage keywords.
+ */
+
+#ifdef HAVE_PROTOTYPES
+#define JMETHOD(type,methodname,arglist) type (*methodname) arglist
+#else
+#define JMETHOD(type,methodname,arglist) type (*methodname) ()
+#endif
+
+
+/* Here is the pseudo-keyword for declaring pointers that must be "far"
+ * on 80x86 machines. Most of the specialized coding for 80x86 is handled
+ * by just saying "FAR *" where such a pointer is needed. In a few places
+ * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
+ */
+
+#ifndef FAR
+#ifdef NEED_FAR_POINTERS
+#define FAR far
+#else
+#define FAR
+#endif
+#endif
+
+
+/*
+ * On a few systems, type boolean and/or its values FALSE, TRUE may appear
+ * in standard header files. Or you may have conflicts with application-
+ * specific header files that you want to include together with these files.
+ * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
+ */
+
+#ifndef HAVE_BOOLEAN
+typedef int boolean;
+#endif
+#ifndef FALSE /* in case these macros already exist */
+#define FALSE 0 /* values of boolean */
+#endif
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+
+/*
+ * The remaining options affect code selection within the JPEG library,
+ * but they don't need to be visible to most applications using the library.
+ * To minimize application namespace pollution, the symbols won't be
+ * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
+ */
+
+#ifdef JPEG_INTERNALS
+#define JPEG_INTERNAL_OPTIONS
+#endif
+
+#ifdef JPEG_INTERNAL_OPTIONS
+
+
+/*
+ * These defines indicate whether to include various optional functions.
+ * Undefining some of these symbols will produce a smaller but less capable
+ * library. Note that you can leave certain source files out of the
+ * compilation/linking process if you've #undef'd the corresponding symbols.
+ * (You may HAVE to do that if your compiler doesn't like null source files.)
+ */
+
+/* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */
+
+/* Capability options common to encoder and decoder: */
+
+#define DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
+#define DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
+#define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
+
+/* Encoder capability options: */
+
+#undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
+#define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
+#define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
+#define C_LOSSLESS_SUPPORTED /* Lossless JPEG? */
+#define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
+/* Note: if you selected 12-bit data precision, it is dangerous to turn off
+ * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit
+ * precision, so jcshuff.c normally uses entropy optimization to compute
+ * usable tables for higher precision. If you don't want to do optimization,
+ * you'll have to supply different default Huffman tables.
+ * The exact same statements apply for progressive and lossless JPEG:
+ * the default tables don't work for progressive mode or lossless mode.
+ * (This may get fixed, however.)
+ */
+#define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
+
+/* Decoder capability options: */
+
+#undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
+#define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
+#define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
+#define D_LOSSLESS_SUPPORTED /* Lossless JPEG? */
+#define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
+#define BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
+#define IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */
+#undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
+#define UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
+#define QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
+#define QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
+
+/* more capability options later, no doubt */
+
+
+/*
+ * Ordering of RGB data in scanlines passed to or from the application.
+ * If your application wants to deal with data in the order B,G,R, just
+ * change these macros. You can also deal with formats such as R,G,B,X
+ * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
+ * the offsets will also change the order in which colormap data is organized.
+ * RESTRICTIONS:
+ * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
+ * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
+ * useful if you are using JPEG color spaces other than YCbCr or grayscale.
+ * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
+ * is not 3 (they don't understand about dummy color components!). So you
+ * can't use color quantization if you change that value.
+ */
+
+#define RGB_RED 0 /* Offset of Red in an RGB scanline element */
+#define RGB_GREEN 1 /* Offset of Green */
+#define RGB_BLUE 2 /* Offset of Blue */
+#define RGB_PIXELSIZE 3 /* JSAMPLEs per RGB scanline element */
+
+
+/* Definitions for speed-related optimizations. */
+
+
+/* If your compiler supports inline functions, define INLINE
+ * as the inline keyword; otherwise define it as empty.
+ */
+
+#ifndef INLINE
+#ifdef __GNUC__ /* for instance, GNU C knows about inline */
+#define INLINE __inline__
+#endif
+#ifndef INLINE
+#define INLINE /* default is to define it as empty */
+#endif
+#endif
+
+
+/* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
+ * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
+ * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
+ */
+
+#ifndef MULTIPLIER
+#define MULTIPLIER int /* type for fastest integer multiply */
+#endif
+
+
+/* FAST_FLOAT should be either float or double, whichever is done faster
+ * by your compiler. (Note that this type is only used in the floating point
+ * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
+ * Typically, float is faster in ANSI C compilers, while double is faster in
+ * pre-ANSI compilers (because they insist on converting to double anyway).
+ * The code below therefore chooses float if we have ANSI-style prototypes.
+ */
+
+#ifndef FAST_FLOAT
+#ifdef HAVE_PROTOTYPES
+#define FAST_FLOAT float
+#else
+#define FAST_FLOAT double
+#endif
+#endif
+
+#if defined ( _MSC_VER )
+#pragma warning ( disable : 4100 )
+#pragma warning ( disable : 4115 )
+#pragma warning ( disable : 4127 )
+#pragma warning ( disable : 4244 )
+#pragma warning ( disable : 4251 )
+#pragma warning ( disable : 4267 )
+#pragma warning ( disable : 4305 )
+#pragma warning ( disable : 4309 )
+#pragma warning ( disable : 4706 )
+#pragma warning ( disable : 4786 )
+#pragma warning ( disable : 4057 )
+#pragma warning ( disable : 4189 )
+#pragma warning ( disable : 4505 )
+#endif
+
+
+#endif /* JPEG_INTERNAL_OPTIONS */
--- /dev/null
+/*
+ * jpegint.h
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file provides common declarations for the various JPEG modules.
+ * These declarations are considered internal to the JPEG library; most
+ * applications using the library shouldn't need to include this file.
+ */
+
+
+/* Declarations for both compression & decompression */
+
+typedef enum { /* Operating modes for buffer controllers */
+ JBUF_PASS_THRU, /* Plain stripwise operation */
+ /* Remaining modes require a full-image buffer to have been created */
+ JBUF_SAVE_SOURCE, /* Run source subobject only, save output */
+ JBUF_CRANK_DEST, /* Run dest subobject only, using saved data */
+ JBUF_SAVE_AND_PASS /* Run both subobjects, save output */
+} J_BUF_MODE;
+
+/* Values of global_state field (jdapi.c has some dependencies on ordering!) */
+#define CSTATE_START 100 /* after create_compress */
+#define CSTATE_SCANNING 101 /* start_compress done, write_scanlines OK */
+#define CSTATE_RAW_OK 102 /* start_compress done, write_raw_data OK */
+#define CSTATE_WRCOEFS 103 /* jpeg_write_coefficients done */
+#define DSTATE_START 200 /* after create_decompress */
+#define DSTATE_INHEADER 201 /* reading header markers, no SOS yet */
+#define DSTATE_READY 202 /* found SOS, ready for start_decompress */
+#define DSTATE_PRELOAD 203 /* reading multiscan file in start_decompress*/
+#define DSTATE_PRESCAN 204 /* performing dummy pass for 2-pass quant */
+#define DSTATE_SCANNING 205 /* start_decompress done, read_scanlines OK */
+#define DSTATE_RAW_OK 206 /* start_decompress done, read_raw_data OK */
+#define DSTATE_BUFIMAGE 207 /* expecting jpeg_start_output */
+#define DSTATE_BUFPOST 208 /* looking for SOS/EOI in jpeg_finish_output */
+#define DSTATE_RDCOEFS 209 /* reading file in jpeg_read_coefficients */
+#define DSTATE_STOPPING 210 /* looking for EOI in jpeg_finish_decompress */
+
+
+/* Declarations for compression modules */
+
+/* Master control module */
+struct jpeg_comp_master {
+ JMETHOD(void, prepare_for_pass, (j_compress_ptr cinfo));
+ JMETHOD(void, pass_startup, (j_compress_ptr cinfo));
+ JMETHOD(void, finish_pass, (j_compress_ptr cinfo));
+
+ /* State variables made visible to other modules */
+ boolean call_pass_startup; /* True if pass_startup must be called */
+ boolean is_last_pass; /* True during last pass */
+};
+
+/* Main buffer control (downsampled-data buffer) */
+struct jpeg_c_main_controller {
+ JMETHOD(void, start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
+ JMETHOD(void, process_data, (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail));
+};
+
+/* Compression preprocessing (downsampling input buffer control) */
+struct jpeg_c_prep_controller {
+ JMETHOD(void, start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
+ JMETHOD(void, pre_process_data, (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf,
+ JDIMENSION *in_row_ctr,
+ JDIMENSION in_rows_avail,
+ JSAMPIMAGE output_buf,
+ JDIMENSION *out_row_group_ctr,
+ JDIMENSION out_row_groups_avail));
+};
+
+/* Compression codec (compressor proper) */
+struct jpeg_c_codec {
+ JMETHOD(void, entropy_start_pass, (j_compress_ptr cinfo,
+ boolean gather_statistics));
+ JMETHOD(void, entropy_finish_pass, (j_compress_ptr cinfo));
+ JMETHOD(boolean, need_optimization_pass, (j_compress_ptr cinfo));
+ JMETHOD(void, start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
+ JMETHOD(boolean, compress_data, (j_compress_ptr cinfo,
+ JSAMPIMAGE input_buf));
+};
+
+/* Colorspace conversion */
+struct jpeg_color_converter {
+ JMETHOD(void, start_pass, (j_compress_ptr cinfo));
+ JMETHOD(void, color_convert, (j_compress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows));
+};
+
+/* Downsampling */
+struct jpeg_downsampler {
+ JMETHOD(void, start_pass, (j_compress_ptr cinfo));
+ JMETHOD(void, downsample, (j_compress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION in_row_index,
+ JSAMPIMAGE output_buf,
+ JDIMENSION out_row_group_index));
+
+ boolean need_context_rows; /* TRUE if need rows above & below */
+};
+
+/* Marker writing */
+struct jpeg_marker_writer {
+ JMETHOD(void, write_file_header, (j_compress_ptr cinfo));
+ JMETHOD(void, write_frame_header, (j_compress_ptr cinfo));
+ JMETHOD(void, write_scan_header, (j_compress_ptr cinfo));
+ JMETHOD(void, write_file_trailer, (j_compress_ptr cinfo));
+ JMETHOD(void, write_tables_only, (j_compress_ptr cinfo));
+ /* These routines are exported to allow insertion of extra markers */
+ /* Probably only COM and APPn markers should be written this way */
+ JMETHOD(void, write_marker_header, (j_compress_ptr cinfo, int marker,
+ unsigned int datalen));
+ JMETHOD(void, write_marker_byte, (j_compress_ptr cinfo, int val));
+};
+
+
+/* Declarations for decompression modules */
+
+/* Master control module */
+struct jpeg_decomp_master {
+ JMETHOD(void, prepare_for_output_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, finish_output_pass, (j_decompress_ptr cinfo));
+
+ /* State variables made visible to other modules */
+ boolean is_dummy_pass; /* True during 1st pass for 2-pass quant */
+};
+
+/* Input control module */
+struct jpeg_input_controller {
+ JMETHOD(int, consume_input, (j_decompress_ptr cinfo));
+ JMETHOD(void, reset_input_controller, (j_decompress_ptr cinfo));
+ JMETHOD(void, start_input_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, finish_input_pass, (j_decompress_ptr cinfo));
+
+ /* State variables made visible to other modules */
+ boolean has_multiple_scans; /* True if file has multiple scans */
+ boolean eoi_reached; /* True when EOI has been consumed */
+};
+
+/* Main buffer control (downsampled-data buffer) */
+struct jpeg_d_main_controller {
+ JMETHOD(void, start_pass, (j_decompress_ptr cinfo, J_BUF_MODE pass_mode));
+ JMETHOD(void, process_data, (j_decompress_ptr cinfo,
+ JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail));
+};
+
+/* Decompression codec (decompressor proper) */
+struct jpeg_d_codec {
+ JMETHOD(void, calc_output_dimensions, (j_decompress_ptr cinfo));
+ JMETHOD(void, start_input_pass, (j_decompress_ptr cinfo));
+ JMETHOD(int, consume_data, (j_decompress_ptr cinfo));
+ JMETHOD(void, start_output_pass, (j_decompress_ptr cinfo));
+ JMETHOD(int, decompress_data, (j_decompress_ptr cinfo,
+ JSAMPIMAGE output_buf));
+};
+
+/* Decompression postprocessing (color quantization buffer control) */
+struct jpeg_d_post_controller {
+ JMETHOD(void, start_pass, (j_decompress_ptr cinfo, J_BUF_MODE pass_mode));
+ JMETHOD(void, post_process_data, (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf,
+ JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf,
+ JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail));
+};
+
+/* Marker reading & parsing */
+struct jpeg_marker_reader {
+ JMETHOD(void, reset_marker_reader, (j_decompress_ptr cinfo));
+ /* Read markers until SOS or EOI.
+ * Returns same codes as are defined for jpeg_consume_input:
+ * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
+ */
+ JMETHOD(int, read_markers, (j_decompress_ptr cinfo));
+ /* Read a restart marker --- exported for use by entropy decoder only */
+ jpeg_marker_parser_method read_restart_marker;
+
+ /* State of marker reader --- nominally internal, but applications
+ * supplying COM or APPn handlers might like to know the state.
+ */
+ boolean saw_SOI; /* found SOI? */
+ boolean saw_SOF; /* found SOF? */
+ int next_restart_num; /* next restart number expected (0-7) */
+ unsigned int discarded_bytes; /* # of bytes skipped looking for a marker */
+};
+
+/* Upsampling (note that upsampler must also call color converter) */
+struct jpeg_upsampler {
+ JMETHOD(void, start_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, upsample, (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf,
+ JDIMENSION *in_row_group_ctr,
+ JDIMENSION in_row_groups_avail,
+ JSAMPARRAY output_buf,
+ JDIMENSION *out_row_ctr,
+ JDIMENSION out_rows_avail));
+
+ boolean need_context_rows; /* TRUE if need rows above & below */
+};
+
+/* Colorspace conversion */
+struct jpeg_color_deconverter {
+ JMETHOD(void, start_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, color_convert, (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows));
+};
+
+/* Color quantization or color precision reduction */
+struct jpeg_color_quantizer {
+ JMETHOD(void, start_pass, (j_decompress_ptr cinfo, boolean is_pre_scan));
+ JMETHOD(void, color_quantize, (j_decompress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPARRAY output_buf,
+ int num_rows));
+ JMETHOD(void, finish_pass, (j_decompress_ptr cinfo));
+ JMETHOD(void, new_color_map, (j_decompress_ptr cinfo));
+};
+
+
+/* Miscellaneous useful macros */
+
+#undef MAX
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+#undef MIN
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+
+
+/* We assume that right shift corresponds to signed division by 2 with
+ * rounding towards minus infinity. This is correct for typical "arithmetic
+ * shift" instructions that shift in copies of the sign bit. But some
+ * C compilers implement >> with an unsigned shift. For these machines you
+ * must define RIGHT_SHIFT_IS_UNSIGNED.
+ * RIGHT_SHIFT provides a proper signed right shift of an INT32 quantity.
+ * It is only applied with constant shift counts. SHIFT_TEMPS must be
+ * included in the variables of any routine using RIGHT_SHIFT.
+ */
+
+#ifdef RIGHT_SHIFT_IS_UNSIGNED
+#define SHIFT_TEMPS INT32 shift_temp;
+#define RIGHT_SHIFT(x,shft) \
+ ((shift_temp = (x)) < 0 ? \
+ (shift_temp >> (shft)) | ((~((INT32) 0)) << (32-(shft))) : \
+ (shift_temp >> (shft)))
+#else
+#define SHIFT_TEMPS
+#define RIGHT_SHIFT(x,shft) ((x) >> (shft))
+#endif
+
+
+/* Short forms of external names for systems with brain-damaged linkers. */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jinit_c_codec jICCodec
+#define jinit_c_diff_controller jICDiffC
+#define jinit_lossy_c_codec jILossyC
+#define jinit_lossless_c_codec jILosslessC
+#define jinit_compress_master jICompress
+#define jinit_c_master_control jICMaster
+#define jinit_c_main_controller jICMainC
+#define jinit_c_prep_controller jICPrepC
+#define jinit_c_coef_controller jICCoefC
+#define jinit_color_converter jICColor
+#define jinit_downsampler jIDownsampler
+#define jinit_forward_dct jIFDCT
+#define jinit_shuff_encoder jISHEncoder
+#define jinit_phuff_encoder jIPHEncoder
+#define jinit_arith_encoder jIAEncoder
+#define jinit_marker_writer jIMWriter
+#define jinit_d_codec jIDCodec
+#define jinit_lossy_d_codec jILossyD
+#define jinit_lossless_d_codec jILosslsD
+#define jinit_master_decompress jIDMaster
+#define jinit_d_main_controller jIDMainC
+#define jinit_d_coef_controller jIDCoefC
+#define jinit_d_diff_controller jIDDiffC
+#define jinit_d_post_controller jIDPostC
+#define jinit_input_controller jIInCtlr
+#define jinit_marker_reader jIMReader
+#define jinit_shuff_decoder jISHDecoder
+#define jinit_phuff_decoder jIPHDecoder
+#define jinit_arith_decoder jIADecoder
+#define jinit_lhuff_decoder jILHDecoder
+#define jinit_undifferencer jIUndiff
+#define jinit_d_scaler jIDScaler
+#define jinit_inverse_dct jIIDCT
+#define jinit_upsampler jIUpsampler
+#define jinit_color_deconverter jIDColor
+#define jinit_1pass_quantizer jI1Quant
+#define jinit_2pass_quantizer jI2Quant
+#define jinit_merged_upsampler jIMUpsampler
+#define jinit_memory_mgr jIMemMgr
+#define jdiv_round_up jDivRound
+#define jround_up jRound
+#define jcopy_sample_rows jCopySamples
+#define jcopy_block_row jCopyBlocks
+#define jzero_far jZeroFar
+#define jpeg_zigzag_order jZIGTable
+#define jpeg_natural_order jZAGTable
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+
+/* Compression module initialization routines */
+EXTERN(void) jinit_c_codec JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_c_diff_controller JPP((j_compress_ptr cinfo, boolean need_full_buffer));
+EXTERN(void) jinit_compress_master JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_c_master_control JPP((j_compress_ptr cinfo,
+ boolean transcode_only));
+EXTERN(void) jinit_c_main_controller JPP((j_compress_ptr cinfo,
+ boolean need_full_buffer));
+EXTERN(void) jinit_c_prep_controller JPP((j_compress_ptr cinfo,
+ boolean need_full_buffer));
+EXTERN(void) jinit_compressor JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_color_converter JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_downsampler JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_marker_writer JPP((j_compress_ptr cinfo));
+EXTERN(void) jinit_arith_encoder JPP((j_compress_ptr cinfo));
+/* Decompression module initialization routines */
+EXTERN(void) jinit_d_codec JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_d_diff_controller JPP((j_decompress_ptr cinfo, boolean need_full_buffer));
+EXTERN(void) jinit_master_decompress JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_d_main_controller JPP((j_decompress_ptr cinfo,
+ boolean need_full_buffer));
+EXTERN(void) jinit_decompressor JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_d_post_controller JPP((j_decompress_ptr cinfo,
+ boolean need_full_buffer));
+EXTERN(void) jinit_input_controller JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_marker_reader JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_arith_decoder JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_upsampler JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_color_deconverter JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_1pass_quantizer JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_2pass_quantizer JPP((j_decompress_ptr cinfo));
+EXTERN(void) jinit_merged_upsampler JPP((j_decompress_ptr cinfo));
+/* Memory manager initialization */
+EXTERN(void) jinit_memory_mgr JPP((j_common_ptr cinfo));
+
+/* Utility routines in jutils.c */
+EXTERN(long) jdiv_round_up JPP((long a, long b));
+EXTERN(long) jround_up JPP((long a, long b));
+EXTERN(void) jcopy_sample_rows JPP((JSAMPARRAY input_array, int source_row,
+ JSAMPARRAY output_array, int dest_row,
+ int num_rows, JDIMENSION num_cols));
+EXTERN(void) jcopy_block_row JPP((JBLOCKROW input_row, JBLOCKROW output_row,
+ JDIMENSION num_blocks));
+EXTERN(void) jzero_far JPP((void FAR * target, size_t bytestozero));
+/* Constant tables in jutils.c */
+#if 0 /* This table is not actually needed in v6a */
+extern const int jpeg_zigzag_order[]; /* natural coef order to zigzag order */
+#endif
+extern const int jpeg_natural_order[]; /* zigzag coef order to natural order */
+
+/* Suppress undefined-structure complaints if necessary. */
+
+#ifdef INCOMPLETE_TYPES_BROKEN
+#ifndef AM_MEMORY_MANAGER /* only jmemmgr.c defines these */
+struct jvirt_sarray_control { long dummy; };
+struct jvirt_barray_control { long dummy; };
+#endif
+#endif /* INCOMPLETE_TYPES_BROKEN */
--- /dev/null
+/*
+ * jpeglib.h
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file defines the application interface for the JPEG library.
+ * Most applications using the library need only include this file,
+ * and perhaps jerror.h if they want to know the exact error codes.
+ */
+
+#ifndef JPEGLIB_H
+#define JPEGLIB_H
+
+/*
+ * First we include the configuration files that record how this
+ * installation of the JPEG library is set up. jconfig.h can be
+ * generated automatically for many systems. jmorecfg.h contains
+ * manual configuration options that most people need not worry about.
+ */
+
+#ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
+#include "jconfig.h" /* widely used configuration options */
+#endif
+#include "jmorecfg.h" /* seldom changed options */
+
+
+/* Version ID for the JPEG library.
+ * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
+ */
+
+#define JPEG_LIB_VERSION 62 /* Version 6b */
+
+
+/* Various constants determining the sizes of things.
+ * All of these are specified by the JPEG standard, so don't change them
+ * if you want to be compatible.
+ */
+
+#define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
+#define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
+#define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
+#define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
+#define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
+#define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
+#define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
+/* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
+ * the PostScript DCT filter can emit files with many more than 10 data units
+ * per MCU.
+ * If you happen to run across such a file, you can up D_MAX_DATA_UNITS_IN_MCU
+ * to handle it. We even let you do this from the jconfig.h file. However,
+ * we strongly discourage changing C_MAX_DATA_UNITS_IN_MCU; just because Adobe
+ * sometimes emits noncompliant files doesn't mean you should too.
+ */
+#define C_MAX_DATA_UNITS_IN_MCU 10 /* compressor's limit on data units/MCU */
+#ifndef D_MAX_DATA_UNITS_IN_MCU
+#define D_MAX_DATA_UNITS_IN_MCU 10 /* decompressor's limit on data units/MCU */
+#endif
+
+
+/* Data structures for images (arrays of samples and of DCT coefficients).
+ * On 80x86 machines, the image arrays are too big for near pointers,
+ * but the pointer arrays can fit in near memory.
+ */
+
+typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
+typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
+typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
+
+typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
+typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
+typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
+typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
+
+typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
+
+typedef JDIFF FAR *JDIFFROW; /* pointer to one row of difference values */
+typedef JDIFFROW *JDIFFARRAY; /* ptr to some rows (a 2-D diff array) */
+typedef JDIFFARRAY *JDIFFIMAGE; /* a 3-D diff array: top index is color */
+
+
+/* Types for JPEG compression parameters and working tables. */
+
+
+/* DCT coefficient quantization tables. */
+
+typedef struct {
+ /* This array gives the coefficient quantizers in natural array order
+ * (not the zigzag order in which they are stored in a JPEG DQT marker).
+ * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
+ */
+ UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
+ /* This field is used only during compression. It's initialized FALSE when
+ * the table is created, and set TRUE when it's been output to the file.
+ * You could suppress output of a table by setting this to TRUE.
+ * (See jpeg_suppress_tables for an example.)
+ */
+ boolean sent_table; /* TRUE when table has been output */
+} JQUANT_TBL;
+
+
+/* Huffman coding tables. */
+
+typedef struct {
+ /* These two fields directly represent the contents of a JPEG DHT marker */
+ UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
+ /* length k bits; bits[0] is unused */
+ UINT8 huffval[256]; /* The symbols, in order of incr code length */
+ /* This field is used only during compression. It's initialized FALSE when
+ * the table is created, and set TRUE when it's been output to the file.
+ * You could suppress output of a table by setting this to TRUE.
+ * (See jpeg_suppress_tables for an example.)
+ */
+ boolean sent_table; /* TRUE when table has been output */
+} JHUFF_TBL;
+
+
+/* Basic info about one component (color channel). */
+
+typedef struct {
+ /* These values are fixed over the whole image. */
+ /* For compression, they must be supplied by parameter setup; */
+ /* for decompression, they are read from the SOF marker. */
+ int component_id; /* identifier for this component (0..255) */
+ int component_index; /* its index in SOF or cinfo->comp_info[] */
+ int h_samp_factor; /* horizontal sampling factor (1..4) */
+ int v_samp_factor; /* vertical sampling factor (1..4) */
+ int quant_tbl_no; /* quantization table selector (0..3) */
+ /* These values may vary between scans. */
+ /* For compression, they must be supplied by parameter setup; */
+ /* for decompression, they are read from the SOS marker. */
+ /* The decompressor output side may not use these variables. */
+ int dc_tbl_no; /* DC entropy table selector (0..3) */
+ int ac_tbl_no; /* AC entropy table selector (0..3) */
+
+ /* Remaining fields should be treated as private by applications. */
+
+ /* These values are computed during compression or decompression startup: */
+ /* Component's size in data units.
+ * Any dummy data units added to complete an MCU are not counted; therefore
+ * these values do not depend on whether a scan is interleaved or not.
+ */
+ JDIMENSION width_in_data_units;
+ JDIMENSION height_in_data_units;
+ /* Size of a data unit in/output by the codec (in samples). Always
+ * data_unit for compression. For decompression this is the size of the
+ * output from one data_unit, reflecting any processing performed by the
+ * codec. For example, in the DCT-based codec, scaling may be applied
+ * during the IDCT step. Values of 1,2,4,8 are likely to be supported.
+ * Note that different components may have different codec_data_unit sizes.
+ */
+ int codec_data_unit;
+ /* The downsampled dimensions are the component's actual, unpadded number
+ * of samples at the main buffer (preprocessing/compression interface), thus
+ * downsampled_width = ceil(image_width * Hi/Hmax)
+ * and similarly for height. For decompression, codec-based processing is
+ * included (ie, IDCT scaling), so
+ * downsampled_width = ceil(image_width * Hi/Hmax * codec_data_unit/data_unit)
+ */
+ JDIMENSION downsampled_width; /* actual width in samples */
+ JDIMENSION downsampled_height; /* actual height in samples */
+ /* This flag is used only for decompression. In cases where some of the
+ * components will be ignored (eg grayscale output from YCbCr image),
+ * we can skip most computations for the unused components.
+ */
+ boolean component_needed; /* do we need the value of this component? */
+
+ /* These values are computed before starting a scan of the component. */
+ /* The decompressor output side may not use these variables. */
+ int MCU_width; /* number of data units per MCU, horizontally */
+ int MCU_height; /* number of data units per MCU, vertically */
+ int MCU_data_units; /* MCU_width * MCU_height */
+ int MCU_sample_width; /* MCU width in samples, MCU_width*codec_data_unit */
+ int last_col_width; /* # of non-dummy data_units across in last MCU */
+ int last_row_height; /* # of non-dummy data_units down in last MCU */
+
+ /* Saved quantization table for component; NULL if none yet saved.
+ * See jdinput.c comments about the need for this information.
+ * This field is currently used only for decompression.
+ */
+ JQUANT_TBL * quant_table;
+
+ /* Private per-component storage for DCT or IDCT subsystem. */
+ void * dct_table;
+} jpeg_component_info;
+
+
+/* The script for encoding a multiple-scan file is an array of these: */
+
+typedef struct {
+ int comps_in_scan; /* number of components encoded in this scan */
+ int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
+ int Ss, Se; /* progressive JPEG spectral selection parms
+ lossless JPEG predictor select parm (Ss) */
+ int Ah, Al; /* progressive JPEG successive approx. parms
+ lossless JPEG point transform parm (Al) */
+} jpeg_scan_info;
+
+/* The decompressor can save APPn and COM markers in a list of these: */
+
+typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
+
+struct jpeg_marker_struct {
+ jpeg_saved_marker_ptr next; /* next in list, or NULL */
+ UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */
+ unsigned int original_length; /* # bytes of data in the file */
+ unsigned int data_length; /* # bytes of data saved at data[] */
+ JOCTET FAR * data; /* the data contained in the marker */
+ /* the marker length word is not counted in data_length or original_length */
+};
+
+/* Known codec processes. */
+
+typedef enum {
+ JPROC_SEQUENTIAL, /* baseline/extended sequential DCT */
+ JPROC_PROGRESSIVE, /* progressive DCT */
+ JPROC_LOSSLESS /* lossless (sequential) */
+} J_CODEC_PROCESS;
+
+/* Known color spaces. */
+
+typedef enum {
+ JCS_UNKNOWN, /* error/unspecified */
+ JCS_GRAYSCALE, /* monochrome */
+ JCS_RGB, /* red/green/blue */
+ JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
+ JCS_CMYK, /* C/M/Y/K */
+ JCS_YCCK /* Y/Cb/Cr/K */
+} J_COLOR_SPACE;
+
+/* DCT/IDCT algorithm options. */
+
+typedef enum {
+ JDCT_ISLOW, /* slow but accurate integer algorithm */
+ JDCT_IFAST, /* faster, less accurate integer method */
+ JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
+} J_DCT_METHOD;
+
+#ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
+#define JDCT_DEFAULT JDCT_ISLOW
+#endif
+#ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
+#define JDCT_FASTEST JDCT_IFAST
+#endif
+
+/* Dithering options for decompression. */
+
+typedef enum {
+ JDITHER_NONE, /* no dithering */
+ JDITHER_ORDERED, /* simple ordered dither */
+ JDITHER_FS /* Floyd-Steinberg error diffusion dither */
+} J_DITHER_MODE;
+
+
+/* Common fields between JPEG compression and decompression master structs. */
+
+#define jpeg_common_fields \
+ struct jpeg_error_mgr * err; /* Error handler module */\
+ struct jpeg_memory_mgr * mem; /* Memory manager module */\
+ struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
+ void * client_data; /* Available for use by application */\
+ boolean is_decompressor; /* So common code can tell which is which */\
+ int global_state /* For checking call sequence validity */
+
+/* Routines that are to be used by both halves of the library are declared
+ * to receive a pointer to this structure. There are no actual instances of
+ * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
+ */
+struct jpeg_common_struct {
+ jpeg_common_fields; /* Fields common to both master struct types */
+ /* Additional fields follow in an actual jpeg_compress_struct or
+ * jpeg_decompress_struct. All three structs must agree on these
+ * initial fields! (This would be a lot cleaner in C++.)
+ */
+};
+
+typedef struct jpeg_common_struct * j_common_ptr;
+typedef struct jpeg_compress_struct * j_compress_ptr;
+typedef struct jpeg_decompress_struct * j_decompress_ptr;
+
+
+/* Master record for a compression instance */
+
+struct jpeg_compress_struct {
+ jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
+
+ /* Destination for compressed data */
+ struct jpeg_destination_mgr * dest;
+
+ /* Description of source image --- these fields must be filled in by
+ * outer application before starting compression. in_color_space must
+ * be correct before you can even call jpeg_set_defaults().
+ */
+
+ JDIMENSION image_width; /* input image width */
+ JDIMENSION image_height; /* input image height */
+ int input_components; /* # of color components in input image */
+ J_COLOR_SPACE in_color_space; /* colorspace of input image */
+
+ double input_gamma; /* image gamma of input image */
+
+ /* Compression parameters --- these fields must be set before calling
+ * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
+ * initialize everything to reasonable defaults, then changing anything
+ * the application specifically wants to change. That way you won't get
+ * burnt when new parameters are added. Also note that there are several
+ * helper routines to simplify changing parameters.
+ */
+
+ boolean lossless; /* TRUE=lossless encoding, FALSE=lossy */
+
+ int data_precision; /* bits of precision in image data */
+
+ int num_components; /* # of color components in JPEG image */
+ J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
+
+ jpeg_component_info * comp_info;
+ /* comp_info[i] describes component that appears i'th in SOF */
+
+ JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
+ /* ptrs to coefficient quantization tables, or NULL if not defined */
+
+ JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
+ JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
+ /* ptrs to Huffman coding tables, or NULL if not defined */
+
+ UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
+ UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
+ UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
+
+ int num_scans; /* # of entries in scan_info array */
+ const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
+ /* The default value of scan_info is NULL, which causes a single-scan
+ * sequential JPEG file to be emitted. To create a multi-scan file,
+ * set num_scans and scan_info to point to an array of scan definitions.
+ */
+
+ boolean raw_data_in; /* TRUE=caller supplies downsampled data */
+ boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
+ boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
+ boolean CCIR601_sampling; /* TRUE=first samples are cosited */
+ int smoothing_factor; /* 1..100, or 0 for no input smoothing */
+ J_DCT_METHOD dct_method; /* DCT algorithm selector */
+
+ /* The restart interval can be specified in absolute MCUs by setting
+ * restart_interval, or in MCU rows by setting restart_in_rows
+ * (in which case the correct restart_interval will be figured
+ * for each scan).
+ */
+ unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
+ int restart_in_rows; /* if > 0, MCU rows per restart interval */
+
+ /* Parameters controlling emission of special markers. */
+
+ boolean write_JFIF_header; /* should a JFIF marker be written? */
+ UINT8 JFIF_major_version; /* What to write for the JFIF version number */
+ UINT8 JFIF_minor_version;
+ /* These three values are not used by the JPEG code, merely copied */
+ /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
+ /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
+ /* ratio is defined by X_density/Y_density even when density_unit=0. */
+ UINT8 density_unit; /* JFIF code for pixel size units */
+ UINT16 X_density; /* Horizontal pixel density */
+ UINT16 Y_density; /* Vertical pixel density */
+ boolean write_Adobe_marker; /* should an Adobe marker be written? */
+
+ /* State variable: index of next scanline to be written to
+ * jpeg_write_scanlines(). Application may use this to control its
+ * processing loop, e.g., "while (next_scanline < image_height)".
+ */
+
+ JDIMENSION next_scanline; /* 0 .. image_height-1 */
+
+ /* Remaining fields are known throughout compressor, but generally
+ * should not be touched by a surrounding application.
+ */
+
+ /*
+ * These fields are computed during compression startup
+ */
+ int data_unit; /* size of data unit in samples */
+ J_CODEC_PROCESS process; /* encoding process of JPEG image */
+
+ int max_h_samp_factor; /* largest h_samp_factor */
+ int max_v_samp_factor; /* largest v_samp_factor */
+
+ JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to codec */
+ /* The codec receives data in units of MCU rows as defined for fully
+ * interleaved scans (whether the JPEG file is interleaved or not).
+ * There are v_samp_factor * data_unit sample rows of each component in an
+ * "iMCU" (interleaved MCU) row.
+ */
+
+ /*
+ * These fields are valid during any one scan.
+ * They describe the components and MCUs actually appearing in the scan.
+ */
+ int comps_in_scan; /* # of JPEG components in this scan */
+ jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
+ /* *cur_comp_info[i] describes component that appears i'th in SOS */
+
+ JDIMENSION MCUs_per_row; /* # of MCUs across the image */
+ JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
+
+ int data_units_in_MCU; /* # of data units per MCU */
+ int MCU_membership[C_MAX_DATA_UNITS_IN_MCU];
+ /* MCU_membership[i] is index in cur_comp_info of component owning */
+ /* i'th block in an MCU */
+
+ int Ss, Se, Ah, Al; /* progressive/lossless JPEG parameters for scan */
+
+ /*
+ * Links to compression subobjects (methods and private variables of modules)
+ */
+ struct jpeg_comp_master * master;
+ struct jpeg_c_main_controller * main;
+ struct jpeg_c_prep_controller * prep;
+ struct jpeg_c_codec * codec;
+ struct jpeg_marker_writer * marker;
+ struct jpeg_color_converter * cconvert;
+ struct jpeg_downsampler * downsample;
+ jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
+ int script_space_size;
+};
+
+
+/* Master record for a decompression instance */
+
+struct jpeg_decompress_struct {
+ jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
+
+ /* Source of compressed data */
+ struct jpeg_source_mgr * src;
+
+ /* Basic description of image --- filled in by jpeg_read_header(). */
+ /* Application may inspect these values to decide how to process image. */
+
+ JDIMENSION image_width; /* nominal image width (from SOF marker) */
+ JDIMENSION image_height; /* nominal image height */
+ int num_components; /* # of color components in JPEG image */
+ J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
+
+ /* Decompression processing parameters --- these fields must be set before
+ * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
+ * them to default values.
+ */
+
+ J_COLOR_SPACE out_color_space; /* colorspace for output */
+
+ unsigned int scale_num, scale_denom; /* fraction by which to scale image */
+
+ double output_gamma; /* image gamma wanted in output */
+
+ boolean buffered_image; /* TRUE=multiple output passes */
+ boolean raw_data_out; /* TRUE=downsampled data wanted */
+
+ J_DCT_METHOD dct_method; /* IDCT algorithm selector */
+ boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
+ boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
+
+ boolean quantize_colors; /* TRUE=colormapped output wanted */
+ /* the following are ignored if not quantize_colors: */
+ J_DITHER_MODE dither_mode; /* type of color dithering to use */
+ boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
+ int desired_number_of_colors; /* max # colors to use in created colormap */
+ /* these are significant only in buffered-image mode: */
+ boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
+ boolean enable_external_quant;/* enable future use of external colormap */
+ boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
+
+ /* Description of actual output image that will be returned to application.
+ * These fields are computed by jpeg_start_decompress().
+ * You can also use jpeg_calc_output_dimensions() to determine these values
+ * in advance of calling jpeg_start_decompress().
+ */
+
+ JDIMENSION output_width; /* scaled image width */
+ JDIMENSION output_height; /* scaled image height */
+ int out_color_components; /* # of color components in out_color_space */
+ int output_components; /* # of color components returned */
+ /* output_components is 1 (a colormap index) when quantizing colors;
+ * otherwise it equals out_color_components.
+ */
+ int rec_outbuf_height; /* min recommended height of scanline buffer */
+ /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
+ * high, space and time will be wasted due to unnecessary data copying.
+ * Usually rec_outbuf_height will be 1 or 2, at most 4.
+ */
+
+ /* When quantizing colors, the output colormap is described by these fields.
+ * The application can supply a colormap by setting colormap non-NULL before
+ * calling jpeg_start_decompress; otherwise a colormap is created during
+ * jpeg_start_decompress or jpeg_start_output.
+ * The map has out_color_components rows and actual_number_of_colors columns.
+ */
+ int actual_number_of_colors; /* number of entries in use */
+ JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
+
+ /* State variables: these variables indicate the progress of decompression.
+ * The application may examine these but must not modify them.
+ */
+
+ /* Row index of next scanline to be read from jpeg_read_scanlines().
+ * Application may use this to control its processing loop, e.g.,
+ * "while (output_scanline < output_height)".
+ */
+ JDIMENSION output_scanline; /* 0 .. output_height-1 */
+
+ /* Current input scan number and number of iMCU rows completed in scan.
+ * These indicate the progress of the decompressor input side.
+ */
+ int input_scan_number; /* Number of SOS markers seen so far */
+ JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
+
+ /* The "output scan number" is the notional scan being displayed by the
+ * output side. The decompressor will not allow output scan/row number
+ * to get ahead of input scan/row, but it can fall arbitrarily far behind.
+ */
+ int output_scan_number; /* Nominal scan number being displayed */
+ JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
+
+ /* Current progression status. coef_bits[c][i] indicates the precision
+ * with which component c's DCT coefficient i (in zigzag order) is known.
+ * It is -1 when no data has yet been received, otherwise it is the point
+ * transform (shift) value for the most recent scan of the coefficient
+ * (thus, 0 at completion of the progression).
+ * This pointer is NULL when reading a non-progressive file.
+ */
+ int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
+
+ /* Internal JPEG parameters --- the application usually need not look at
+ * these fields. Note that the decompressor output side may not use
+ * any parameters that can change between scans.
+ */
+
+ /* Quantization and Huffman tables are carried forward across input
+ * datastreams when processing abbreviated JPEG datastreams.
+ */
+
+ JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
+ /* ptrs to coefficient quantization tables, or NULL if not defined */
+
+ JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
+ JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
+ /* ptrs to Huffman coding tables, or NULL if not defined */
+
+ /* These parameters are never carried across datastreams, since they
+ * are given in SOF/SOS markers or defined to be reset by SOI.
+ */
+
+ int data_precision; /* bits of precision in image data */
+
+ jpeg_component_info * comp_info;
+ /* comp_info[i] describes component that appears i'th in SOF */
+
+ boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
+
+ UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
+ UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
+ UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
+
+ unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
+
+ /* These fields record data obtained from optional markers recognized by
+ * the JPEG library.
+ */
+ boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
+ /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
+ UINT8 JFIF_major_version; /* JFIF version number */
+ UINT8 JFIF_minor_version;
+ UINT8 density_unit; /* JFIF code for pixel size units */
+ UINT16 X_density; /* Horizontal pixel density */
+ UINT16 Y_density; /* Vertical pixel density */
+ boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
+ UINT8 Adobe_transform; /* Color transform code from Adobe marker */
+
+ boolean CCIR601_sampling; /* TRUE=first samples are cosited */
+
+ /* Aside from the specific data retained from APPn markers known to the
+ * library, the uninterpreted contents of any or all APPn and COM markers
+ * can be saved in a list for examination by the application.
+ */
+ jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
+
+ /* Remaining fields are known throughout decompressor, but generally
+ * should not be touched by a surrounding application.
+ */
+
+ /*
+ * These fields are computed during decompression startup
+ */
+ int data_unit; /* size of data unit in samples */
+ J_CODEC_PROCESS process; /* decoding process of JPEG image */
+
+ int max_h_samp_factor; /* largest h_samp_factor */
+ int max_v_samp_factor; /* largest v_samp_factor */
+
+ int min_codec_data_unit; /* smallest codec_data_unit of any component */
+
+ JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
+ /* The codec's input and output progress is measured in units of "iMCU"
+ * (interleaved MCU) rows. These are the same as MCU rows in fully
+ * interleaved JPEG scans, but are used whether the scan is interleaved
+ * or not. We define an iMCU row as v_samp_factor data_unit rows of each
+ * component. Therefore, the codec output contains
+ * v_samp_factor*codec_data_unit sample rows of a component per iMCU row.
+ */
+
+ JSAMPLE * sample_range_limit; /* table for fast range-limiting */
+
+ /*
+ * These fields are valid during any one scan.
+ * They describe the components and MCUs actually appearing in the scan.
+ * Note that the decompressor output side must not use these fields.
+ */
+ int comps_in_scan; /* # of JPEG components in this scan */
+ jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
+ /* *cur_comp_info[i] describes component that appears i'th in SOS */
+
+ JDIMENSION MCUs_per_row; /* # of MCUs across the image */
+ JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
+
+ int data_units_in_MCU; /* # of data _units per MCU */
+ int MCU_membership[D_MAX_DATA_UNITS_IN_MCU];
+ /* MCU_membership[i] is index in cur_comp_info of component owning */
+ /* i'th data unit in an MCU */
+
+ int Ss, Se, Ah, Al; /* progressive/lossless JPEG parms for scan */
+
+ /* This field is shared between entropy decoder and marker parser.
+ * It is either zero or the code of a JPEG marker that has been
+ * read from the data source, but has not yet been processed.
+ */
+ int unread_marker;
+
+ /*
+ * Links to decompression subobjects (methods, private variables of modules)
+ */
+ struct jpeg_decomp_master * master;
+ struct jpeg_d_main_controller * main;
+ struct jpeg_d_codec * codec;
+ struct jpeg_d_post_controller * post;
+ struct jpeg_input_controller * inputctl;
+ struct jpeg_marker_reader * marker;
+ struct jpeg_upsampler * upsample;
+ struct jpeg_color_deconverter * cconvert;
+ struct jpeg_color_quantizer * cquantize;
+};
+
+
+/* "Object" declarations for JPEG modules that may be supplied or called
+ * directly by the surrounding application.
+ * As with all objects in the JPEG library, these structs only define the
+ * publicly visible methods and state variables of a module. Additional
+ * private fields may exist after the public ones.
+ */
+
+
+/* Error handler object */
+
+struct jpeg_error_mgr {
+ /* Error exit handler: does not return to caller */
+ JMETHOD(void, error_exit, (j_common_ptr cinfo));
+ /* Conditionally emit a trace or warning message */
+ JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
+ /* Routine that actually outputs a trace or error message */
+ JMETHOD(void, output_message, (j_common_ptr cinfo));
+ /* Format a message string for the most recent JPEG error or message */
+ JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
+#define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
+ /* Reset error state variables at start of a new image */
+ JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
+
+ /* The message ID code and any parameters are saved here.
+ * A message can have one string parameter or up to 8 int parameters.
+ */
+ int msg_code;
+#define JMSG_STR_PARM_MAX 80
+ union {
+ int i[8];
+ char s[JMSG_STR_PARM_MAX];
+ } msg_parm;
+
+ /* Standard state variables for error facility */
+
+ int trace_level; /* max msg_level that will be displayed */
+
+ /* For recoverable corrupt-data errors, we emit a warning message,
+ * but keep going unless emit_message chooses to abort. emit_message
+ * should count warnings in num_warnings. The surrounding application
+ * can check for bad data by seeing if num_warnings is nonzero at the
+ * end of processing.
+ */
+ long num_warnings; /* number of corrupt-data warnings */
+
+ /* These fields point to the table(s) of error message strings.
+ * An application can change the table pointer to switch to a different
+ * message list (typically, to change the language in which errors are
+ * reported). Some applications may wish to add additional error codes
+ * that will be handled by the JPEG library error mechanism; the second
+ * table pointer is used for this purpose.
+ *
+ * First table includes all errors generated by JPEG library itself.
+ * Error code 0 is reserved for a "no such error string" message.
+ */
+ const char * const * jpeg_message_table; /* Library errors */
+ int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
+ /* Second table can be added by application (see cjpeg/djpeg for example).
+ * It contains strings numbered first_addon_message..last_addon_message.
+ */
+ const char * const * addon_message_table; /* Non-library errors */
+ int first_addon_message; /* code for first string in addon table */
+ int last_addon_message; /* code for last string in addon table */
+};
+
+
+/* Progress monitor object */
+
+struct jpeg_progress_mgr {
+ JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
+
+ long pass_counter; /* work units completed in this pass */
+ long pass_limit; /* total number of work units in this pass */
+ int completed_passes; /* passes completed so far */
+ int total_passes; /* total number of passes expected */
+};
+
+
+/* Data destination object for compression */
+
+struct jpeg_destination_mgr {
+ JOCTET * next_output_byte; /* => next byte to write in buffer */
+ size_t free_in_buffer; /* # of byte spaces remaining in buffer */
+
+ JMETHOD(void, init_destination, (j_compress_ptr cinfo));
+ JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
+ JMETHOD(void, term_destination, (j_compress_ptr cinfo));
+};
+
+
+/* Data source object for decompression */
+
+struct jpeg_source_mgr {
+ const JOCTET * next_input_byte; /* => next byte to read from buffer */
+ size_t bytes_in_buffer; /* # of bytes remaining in buffer */
+
+ JMETHOD(void, init_source, (j_decompress_ptr cinfo));
+ JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
+ JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
+ JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
+ JMETHOD(void, term_source, (j_decompress_ptr cinfo));
+};
+
+
+/* Memory manager object.
+ * Allocates "small" objects (a few K total), "large" objects (tens of K),
+ * and "really big" objects (virtual arrays with backing store if needed).
+ * The memory manager does not allow individual objects to be freed; rather,
+ * each created object is assigned to a pool, and whole pools can be freed
+ * at once. This is faster and more convenient than remembering exactly what
+ * to free, especially where malloc()/free() are not too speedy.
+ * NB: alloc routines never return NULL. They exit to error_exit if not
+ * successful.
+ */
+
+#define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
+#define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
+#define JPOOL_NUMPOOLS 2
+
+typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
+typedef struct jvirt_barray_control * jvirt_barray_ptr;
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+#define NEED_DARRAY
+#else
+#ifdef D_LOSSLESS_SUPPORTED
+#define NEED_DARRAY
+#endif
+#endif
+
+struct jpeg_memory_mgr {
+ /* Method pointers */
+ JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
+ size_t sizeofobject));
+ JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
+ size_t sizeofobject));
+ JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
+ JDIMENSION samplesperrow,
+ JDIMENSION numrows));
+ JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
+ JDIMENSION blocksperrow,
+ JDIMENSION numrows));
+#ifdef NEED_DARRAY
+ JMETHOD(JDIFFARRAY, alloc_darray, (j_common_ptr cinfo, int pool_id,
+ JDIMENSION diffsperrow,
+ JDIMENSION numrows));
+#endif
+ JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
+ int pool_id,
+ boolean pre_zero,
+ JDIMENSION samplesperrow,
+ JDIMENSION numrows,
+ JDIMENSION maxaccess));
+ JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
+ int pool_id,
+ boolean pre_zero,
+ JDIMENSION blocksperrow,
+ JDIMENSION numrows,
+ JDIMENSION maxaccess));
+ JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
+ JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
+ jvirt_sarray_ptr ptr,
+ JDIMENSION start_row,
+ JDIMENSION num_rows,
+ boolean writable));
+ JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
+ jvirt_barray_ptr ptr,
+ JDIMENSION start_row,
+ JDIMENSION num_rows,
+ boolean writable));
+ JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
+ JMETHOD(void, self_destruct, (j_common_ptr cinfo));
+
+ /* Limit on memory allocation for this JPEG object. (Note that this is
+ * merely advisory, not a guaranteed maximum; it only affects the space
+ * used for virtual-array buffers.) May be changed by outer application
+ * after creating the JPEG object.
+ */
+ long max_memory_to_use;
+
+ /* Maximum allocation request accepted by alloc_large. */
+ long max_alloc_chunk;
+};
+
+
+/* Routine signature for application-supplied marker processing methods.
+ * Need not pass marker code since it is stored in cinfo->unread_marker.
+ */
+typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
+
+
+/* Declarations for routines called by application.
+ * The JPP macro hides prototype parameters from compilers that can't cope.
+ * Note JPP requires double parentheses.
+ */
+
+#ifdef HAVE_PROTOTYPES
+#define JPP(arglist) arglist
+#else
+#define JPP(arglist) ()
+#endif
+
+
+/* Short forms of external names for systems with brain-damaged linkers.
+ * We shorten external names to be unique in the first six letters, which
+ * is good enough for all known systems.
+ * (If your compiler itself needs names to be unique in less than 15
+ * characters, you are out of luck. Get a better compiler.)
+ */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_std_error jStdError
+#define jpeg_CreateCompress jCreaCompress
+#define jpeg_CreateDecompress jCreaDecompress
+#define jpeg_destroy_compress jDestCompress
+#define jpeg_destroy_decompress jDestDecompress
+#define jpeg_stdio_dest jStdDest
+#define jpeg_stdio_src jStdSrc
+#define jpeg_set_defaults jSetDefaults
+#define jpeg_set_colorspace jSetColorspace
+#define jpeg_default_colorspace jDefColorspace
+#define jpeg_set_quality jSetQuality
+#define jpeg_set_linear_quality jSetLQuality
+#define jpeg_add_quant_table jAddQuantTable
+#define jpeg_quality_scaling jQualityScaling
+#define jpeg_simple_lossless jSimLossless
+#define jpeg_simple_progression jSimProgress
+#define jpeg_suppress_tables jSuppressTables
+#define jpeg_alloc_quant_table jAlcQTable
+#define jpeg_alloc_huff_table jAlcHTable
+#define jpeg_start_compress jStrtCompress
+#define jpeg_write_scanlines jWrtScanlines
+#define jpeg_finish_compress jFinCompress
+#define jpeg_write_raw_data jWrtRawData
+#define jpeg_write_marker jWrtMarker
+#define jpeg_write_m_header jWrtMHeader
+#define jpeg_write_m_byte jWrtMByte
+#define jpeg_write_tables jWrtTables
+#define jpeg_read_header jReadHeader
+#define jpeg_start_decompress jStrtDecompress
+#define jpeg_read_scanlines jReadScanlines
+#define jpeg_finish_decompress jFinDecompress
+#define jpeg_read_raw_data jReadRawData
+#define jpeg_has_multiple_scans jHasMultScn
+#define jpeg_start_output jStrtOutput
+#define jpeg_finish_output jFinOutput
+#define jpeg_input_complete jInComplete
+#define jpeg_new_colormap jNewCMap
+#define jpeg_consume_input jConsumeInput
+#define jpeg_calc_output_dimensions jCalcDimensions
+#define jpeg_save_markers jSaveMarkers
+#define jpeg_set_marker_processor jSetMarker
+#define jpeg_read_coefficients jReadCoefs
+#define jpeg_write_coefficients jWrtCoefs
+#define jpeg_copy_critical_parameters jCopyCrit
+#define jpeg_abort_compress jAbrtCompress
+#define jpeg_abort_decompress jAbrtDecompress
+#define jpeg_abort jAbort
+#define jpeg_destroy jDestroy
+#define jpeg_resync_to_restart jResyncRestart
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+
+/* Default error-management setup */
+EXTERN(struct jpeg_error_mgr *) jpeg_std_error
+ JPP((struct jpeg_error_mgr * err));
+
+/* Initialization of JPEG compression objects.
+ * jpeg_create_compress() and jpeg_create_decompress() are the exported
+ * names that applications should call. These expand to calls on
+ * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
+ * passed for version mismatch checking.
+ * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
+ */
+#define jpeg_create_compress(cinfo) \
+ jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
+ (size_t) sizeof(struct jpeg_compress_struct))
+#define jpeg_create_decompress(cinfo) \
+ jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
+ (size_t) sizeof(struct jpeg_decompress_struct))
+EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
+ int version, size_t structsize));
+EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
+ int version, size_t structsize));
+/* Destruction of JPEG compression objects */
+EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
+EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
+
+/* Standard data source and destination managers: stdio streams. */
+/* Caller is responsible for opening the file before and closing after. */
+EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
+EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
+
+/* Default parameter setup for compression */
+EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
+/* Compression parameter setup aids */
+EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
+ J_COLOR_SPACE colorspace));
+EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
+EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
+ boolean force_baseline));
+EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
+ int scale_factor,
+ boolean force_baseline));
+EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
+ const unsigned int *basic_table,
+ int scale_factor,
+ boolean force_baseline));
+EXTERN(int) jpeg_quality_scaling JPP((int quality));
+EXTERN(void) jpeg_simple_lossless JPP((j_compress_ptr cinfo,
+ int predictor, int point_transform));
+EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
+EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
+ boolean suppress));
+EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
+EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
+
+/* Main entry points for compression */
+EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
+ boolean write_all_tables));
+EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
+ JSAMPARRAY scanlines,
+ JDIMENSION num_lines));
+EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
+
+/* Replaces jpeg_write_scanlines when writing raw downsampled data. */
+EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
+ JSAMPIMAGE data,
+ JDIMENSION num_lines));
+
+/* Write a special marker. See libjpeg.doc concerning safe usage. */
+EXTERN(void) jpeg_write_marker
+ JPP((j_compress_ptr cinfo, int marker,
+ const JOCTET * dataptr, unsigned int datalen));
+/* Same, but piecemeal. */
+EXTERN(void) jpeg_write_m_header
+ JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
+EXTERN(void) jpeg_write_m_byte
+ JPP((j_compress_ptr cinfo, int val));
+
+/* Alternate compression function: just write an abbreviated table file */
+EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
+
+/* Decompression startup: read start of JPEG datastream to see what's there */
+EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
+ boolean require_image));
+/* Return value is one of: */
+#define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
+#define JPEG_HEADER_OK 1 /* Found valid image datastream */
+#define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
+/* If you pass require_image = TRUE (normal case), you need not check for
+ * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
+ * JPEG_SUSPENDED is only possible if you use a data source module that can
+ * give a suspension return (the stdio source module doesn't).
+ */
+
+/* Main entry points for decompression */
+EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
+EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
+ JSAMPARRAY scanlines,
+ JDIMENSION max_lines));
+EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
+
+/* Replaces jpeg_read_scanlines when reading raw downsampled data. */
+EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
+ JSAMPIMAGE data,
+ JDIMENSION max_lines));
+
+/* Additional entry points for buffered-image mode. */
+EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
+EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
+ int scan_number));
+EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
+EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
+EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
+EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
+/* Return value is one of: */
+/* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
+#define JPEG_REACHED_SOS 1 /* Reached start of new scan */
+#define JPEG_REACHED_EOI 2 /* Reached end of image */
+#define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
+#define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
+
+/* Precalculate output dimensions for current decompression parameters. */
+EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
+
+/* Control saving of COM and APPn markers into marker_list. */
+EXTERN(void) jpeg_save_markers
+ JPP((j_decompress_ptr cinfo, int marker_code,
+ unsigned int length_limit));
+
+/* Install a special processing method for COM or APPn markers. */
+EXTERN(void) jpeg_set_marker_processor
+ JPP((j_decompress_ptr cinfo, int marker_code,
+ jpeg_marker_parser_method routine));
+
+/* Read or write raw DCT coefficients --- useful for lossless transcoding. */
+EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
+EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
+ jvirt_barray_ptr * coef_arrays));
+EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
+ j_compress_ptr dstinfo));
+
+/* If you choose to abort compression or decompression before completing
+ * jpeg_finish_(de)compress, then you need to clean up to release memory,
+ * temporary files, etc. You can just call jpeg_destroy_(de)compress
+ * if you're done with the JPEG object, but if you want to clean it up and
+ * reuse it, call this:
+ */
+EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
+EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
+
+/* Generic versions of jpeg_abort and jpeg_destroy that work on either
+ * flavor of JPEG object. These may be more convenient in some places.
+ */
+EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
+EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
+
+/* Default restart-marker-resync procedure for use by data source modules */
+EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
+ int desired));
+
+
+/* These marker codes are exported since applications and data source modules
+ * are likely to want to use them.
+ */
+
+#define JPEG_RST0 0xD0 /* RST0 marker code */
+#define JPEG_EOI 0xD9 /* EOI marker code */
+#define JPEG_APP0 0xE0 /* APP0 marker code */
+#define JPEG_COM 0xFE /* COM marker code */
+
+
+/* If we have a brain-damaged compiler that emits warnings (or worse, errors)
+ * for structure definitions that are never filled in, keep it quiet by
+ * supplying dummy definitions for the various substructures.
+ */
+
+#ifdef INCOMPLETE_TYPES_BROKEN
+#ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
+struct jvirt_sarray_control { long dummy; };
+struct jvirt_barray_control { long dummy; };
+struct jpeg_comp_master { long dummy; };
+struct jpeg_c_main_controller { long dummy; };
+struct jpeg_c_prep_controller { long dummy; };
+struct jpeg_c_coef_controller { long dummy; };
+struct jpeg_marker_writer { long dummy; };
+struct jpeg_color_converter { long dummy; };
+struct jpeg_downsampler { long dummy; };
+struct jpeg_forward_dct { long dummy; };
+struct jpeg_entropy_encoder { long dummy; };
+struct jpeg_decomp_master { long dummy; };
+struct jpeg_d_main_controller { long dummy; };
+struct jpeg_d_coef_controller { long dummy; };
+struct jpeg_d_post_controller { long dummy; };
+struct jpeg_input_controller { long dummy; };
+struct jpeg_marker_reader { long dummy; };
+struct jpeg_entropy_decoder { long dummy; };
+struct jpeg_inverse_dct { long dummy; };
+struct jpeg_upsampler { long dummy; };
+struct jpeg_color_deconverter { long dummy; };
+struct jpeg_color_quantizer { long dummy; };
+#endif /* JPEG_INTERNALS */
+#endif /* INCOMPLETE_TYPES_BROKEN */
+
+
+/*
+ * The JPEG library modules define JPEG_INTERNALS before including this file.
+ * The internal structure declarations are read only when that is true.
+ * Applications using the library should not include jpegint.h, but may wish
+ * to include jerror.h.
+ */
+
+#ifdef JPEG_INTERNALS
+#include "jpegint.h" /* fetch private declarations */
+#include "jerror.h" /* fetch error codes too */
+#endif
+
+#endif /* JPEGLIB_H */
--- /dev/null
+/*
+ * jquant1.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains 1-pass color quantization (color mapping) routines.
+ * These routines provide mapping to a fixed color map using equally spaced
+ * color values. Optional Floyd-Steinberg or ordered dithering is available.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+#ifdef QUANT_1PASS_SUPPORTED
+
+
+/*
+ * The main purpose of 1-pass quantization is to provide a fast, if not very
+ * high quality, colormapped output capability. A 2-pass quantizer usually
+ * gives better visual quality; however, for quantized grayscale output this
+ * quantizer is perfectly adequate. Dithering is highly recommended with this
+ * quantizer, though you can turn it off if you really want to.
+ *
+ * In 1-pass quantization the colormap must be chosen in advance of seeing the
+ * image. We use a map consisting of all combinations of Ncolors[i] color
+ * values for the i'th component. The Ncolors[] values are chosen so that
+ * their product, the total number of colors, is no more than that requested.
+ * (In most cases, the product will be somewhat less.)
+ *
+ * Since the colormap is orthogonal, the representative value for each color
+ * component can be determined without considering the other components;
+ * then these indexes can be combined into a colormap index by a standard
+ * N-dimensional-array-subscript calculation. Most of the arithmetic involved
+ * can be precalculated and stored in the lookup table colorindex[].
+ * colorindex[i][j] maps pixel value j in component i to the nearest
+ * representative value (grid plane) for that component; this index is
+ * multiplied by the array stride for component i, so that the
+ * index of the colormap entry closest to a given pixel value is just
+ * sum( colorindex[component-number][pixel-component-value] )
+ * Aside from being fast, this scheme allows for variable spacing between
+ * representative values with no additional lookup cost.
+ *
+ * If gamma correction has been applied in color conversion, it might be wise
+ * to adjust the color grid spacing so that the representative colors are
+ * equidistant in linear space. At this writing, gamma correction is not
+ * implemented by jdcolor, so nothing is done here.
+ */
+
+
+/* Declarations for ordered dithering.
+ *
+ * We use a standard 16x16 ordered dither array. The basic concept of ordered
+ * dithering is described in many references, for instance Dale Schumacher's
+ * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991).
+ * In place of Schumacher's comparisons against a "threshold" value, we add a
+ * "dither" value to the input pixel and then round the result to the nearest
+ * output value. The dither value is equivalent to (0.5 - threshold) times
+ * the distance between output values. For ordered dithering, we assume that
+ * the output colors are equally spaced; if not, results will probably be
+ * worse, since the dither may be too much or too little at a given point.
+ *
+ * The normal calculation would be to form pixel value + dither, range-limit
+ * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual.
+ * We can skip the separate range-limiting step by extending the colorindex
+ * table in both directions.
+ */
+
+#define ODITHER_SIZE 16 /* dimension of dither matrix */
+/* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */
+#define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */
+#define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */
+
+typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE];
+typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE];
+
+static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = {
+ /* Bayer's order-4 dither array. Generated by the code given in
+ * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I.
+ * The values in this array must range from 0 to ODITHER_CELLS-1.
+ */
+ { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 },
+ { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 },
+ { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 },
+ { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 },
+ { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 },
+ { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 },
+ { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 },
+ { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 },
+ { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 },
+ { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 },
+ { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 },
+ { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 },
+ { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 },
+ { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 },
+ { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 },
+ { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 }
+};
+
+
+/* Declarations for Floyd-Steinberg dithering.
+ *
+ * Errors are accumulated into the array fserrors[], at a resolution of
+ * 1/16th of a pixel count. The error at a given pixel is propagated
+ * to its not-yet-processed neighbors using the standard F-S fractions,
+ * ... (here) 7/16
+ * 3/16 5/16 1/16
+ * We work left-to-right on even rows, right-to-left on odd rows.
+ *
+ * We can get away with a single array (holding one row's worth of errors)
+ * by using it to store the current row's errors at pixel columns not yet
+ * processed, but the next row's errors at columns already processed. We
+ * need only a few extra variables to hold the errors immediately around the
+ * current column. (If we are lucky, those variables are in registers, but
+ * even if not, they're probably cheaper to access than array elements are.)
+ *
+ * The fserrors[] array is indexed [component#][position].
+ * We provide (#columns + 2) entries per component; the extra entry at each
+ * end saves us from special-casing the first and last pixels.
+ *
+ * Note: on a wide image, we might not have enough room in a PC's near data
+ * segment to hold the error array; so it is allocated with alloc_large.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+typedef INT16 FSERROR; /* 16 bits should be enough */
+typedef int LOCFSERROR; /* use 'int' for calculation temps */
+#else
+typedef INT32 FSERROR; /* may need more than 16 bits */
+typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */
+#endif
+
+typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */
+
+
+/* Private subobject */
+
+#define MAX_Q_COMPS 4 /* max components I can handle */
+
+typedef struct {
+ struct jpeg_color_quantizer pub; /* public fields */
+
+ /* Initially allocated colormap is saved here */
+ JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */
+ int sv_actual; /* number of entries in use */
+
+ JSAMPARRAY colorindex; /* Precomputed mapping for speed */
+ /* colorindex[i][j] = index of color closest to pixel value j in component i,
+ * premultiplied as described above. Since colormap indexes must fit into
+ * JSAMPLEs, the entries of this array will too.
+ */
+ boolean is_padded; /* is the colorindex padded for odither? */
+
+ int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */
+
+ /* Variables for ordered dithering */
+ int row_index; /* cur row's vertical index in dither matrix */
+ ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */
+
+ /* Variables for Floyd-Steinberg dithering */
+ FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */
+ boolean on_odd_row; /* flag to remember which row we are on */
+} my_cquantizer;
+
+typedef my_cquantizer * my_cquantize_ptr;
+
+
+/*
+ * Policy-making subroutines for create_colormap and create_colorindex.
+ * These routines determine the colormap to be used. The rest of the module
+ * only assumes that the colormap is orthogonal.
+ *
+ * * select_ncolors decides how to divvy up the available colors
+ * among the components.
+ * * output_value defines the set of representative values for a component.
+ * * largest_input_value defines the mapping from input values to
+ * representative values for a component.
+ * Note that the latter two routines may impose different policies for
+ * different components, though this is not currently done.
+ */
+
+
+LOCAL(int)
+select_ncolors (j_decompress_ptr cinfo, int Ncolors[])
+/* Determine allocation of desired colors to components, */
+/* and fill in Ncolors[] array to indicate choice. */
+/* Return value is total number of colors (product of Ncolors[] values). */
+{
+ int nc = cinfo->out_color_components; /* number of color components */
+ int max_colors = cinfo->desired_number_of_colors;
+ int total_colors, iroot, i, j;
+ boolean changed;
+ long temp;
+ static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE };
+
+ /* We can allocate at least the nc'th root of max_colors per component. */
+ /* Compute floor(nc'th root of max_colors). */
+ iroot = 1;
+ do {
+ iroot++;
+ temp = iroot; /* set temp = iroot ** nc */
+ for (i = 1; i < nc; i++)
+ temp *= iroot;
+ } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */
+ iroot--; /* now iroot = floor(root) */
+
+ /* Must have at least 2 color values per component */
+ if (iroot < 2)
+ ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp);
+
+ /* Initialize to iroot color values for each component */
+ total_colors = 1;
+ for (i = 0; i < nc; i++) {
+ Ncolors[i] = iroot;
+ total_colors *= iroot;
+ }
+ /* We may be able to increment the count for one or more components without
+ * exceeding max_colors, though we know not all can be incremented.
+ * Sometimes, the first component can be incremented more than once!
+ * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.)
+ * In RGB colorspace, try to increment G first, then R, then B.
+ */
+ do {
+ changed = FALSE;
+ for (i = 0; i < nc; i++) {
+ j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i);
+ /* calculate new total_colors if Ncolors[j] is incremented */
+ temp = total_colors / Ncolors[j];
+ temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */
+ if (temp > (long) max_colors)
+ break; /* won't fit, done with this pass */
+ Ncolors[j]++; /* OK, apply the increment */
+ total_colors = (int) temp;
+ changed = TRUE;
+ }
+ } while (changed);
+
+ return total_colors;
+}
+
+
+LOCAL(int)
+output_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
+/* Return j'th output value, where j will range from 0 to maxj */
+/* The output values must fall in 0..MAXJSAMPLE in increasing order */
+{
+ (void)cinfo;(void)ci;
+ /* We always provide values 0 and MAXJSAMPLE for each component;
+ * any additional values are equally spaced between these limits.
+ * (Forcing the upper and lower values to the limits ensures that
+ * dithering can't produce a color outside the selected gamut.)
+ */
+ return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj);
+}
+
+
+LOCAL(int)
+largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
+/* Return largest input value that should map to j'th output value */
+/* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */
+{
+ (void)cinfo;(void)ci;
+ /* Breakpoints are halfway between values returned by output_value */
+ return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj));
+}
+
+
+/*
+ * Create the colormap.
+ */
+
+LOCAL(void)
+create_colormap (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ JSAMPARRAY colormap; /* Created colormap */
+ int total_colors; /* Number of distinct output colors */
+ int i,j,k, nci, blksize, blkdist, ptr, val;
+
+ /* Select number of colors for each component */
+ total_colors = select_ncolors(cinfo, cquantize->Ncolors);
+
+ /* Report selected color counts */
+ if (cinfo->out_color_components == 3)
+ TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS,
+ total_colors, cquantize->Ncolors[0],
+ cquantize->Ncolors[1], cquantize->Ncolors[2]);
+ else
+ TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors);
+
+ /* Allocate and fill in the colormap. */
+ /* The colors are ordered in the map in standard row-major order, */
+ /* i.e. rightmost (highest-indexed) color changes most rapidly. */
+
+ colormap = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components);
+
+ /* blksize is number of adjacent repeated entries for a component */
+ /* blkdist is distance between groups of identical entries for a component */
+ blkdist = total_colors;
+
+ for (i = 0; i < cinfo->out_color_components; i++) {
+ /* fill in colormap entries for i'th color component */
+ nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
+ blksize = blkdist / nci;
+ for (j = 0; j < nci; j++) {
+ /* Compute j'th output value (out of nci) for component */
+ val = output_value(cinfo, i, j, nci-1);
+ /* Fill in all colormap entries that have this value of this component */
+ for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {
+ /* fill in blksize entries beginning at ptr */
+ for (k = 0; k < blksize; k++)
+ colormap[i][ptr+k] = (JSAMPLE) val;
+ }
+ }
+ blkdist = blksize; /* blksize of this color is blkdist of next */
+ }
+
+ /* Save the colormap in private storage,
+ * where it will survive color quantization mode changes.
+ */
+ cquantize->sv_colormap = colormap;
+ cquantize->sv_actual = total_colors;
+}
+
+
+/*
+ * Create the color index table.
+ */
+
+LOCAL(void)
+create_colorindex (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ JSAMPROW indexptr;
+ int i,j,k, nci, blksize, val, pad;
+
+ /* For ordered dither, we pad the color index tables by MAXJSAMPLE in
+ * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE).
+ * This is not necessary in the other dithering modes. However, we
+ * flag whether it was done in case user changes dithering mode.
+ */
+ if (cinfo->dither_mode == JDITHER_ORDERED) {
+ pad = MAXJSAMPLE*2;
+ cquantize->is_padded = TRUE;
+ } else {
+ pad = 0;
+ cquantize->is_padded = FALSE;
+ }
+
+ cquantize->colorindex = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) (MAXJSAMPLE+1 + pad),
+ (JDIMENSION) cinfo->out_color_components);
+
+ /* blksize is number of adjacent repeated entries for a component */
+ blksize = cquantize->sv_actual;
+
+ for (i = 0; i < cinfo->out_color_components; i++) {
+ /* fill in colorindex entries for i'th color component */
+ nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
+ blksize = blksize / nci;
+
+ /* adjust colorindex pointers to provide padding at negative indexes. */
+ if (pad)
+ cquantize->colorindex[i] += MAXJSAMPLE;
+
+ /* in loop, val = index of current output value, */
+ /* and k = largest j that maps to current val */
+ indexptr = cquantize->colorindex[i];
+ val = 0;
+ k = largest_input_value(cinfo, i, 0, nci-1);
+ for (j = 0; j <= MAXJSAMPLE; j++) {
+ while (j > k) /* advance val if past boundary */
+ k = largest_input_value(cinfo, i, ++val, nci-1);
+ /* premultiply so that no multiplication needed in main processing */
+ indexptr[j] = (JSAMPLE) (val * blksize);
+ }
+ /* Pad at both ends if necessary */
+ if (pad)
+ for (j = 1; j <= MAXJSAMPLE; j++) {
+ indexptr[-j] = indexptr[0];
+ indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE];
+ }
+ }
+}
+
+
+/*
+ * Create an ordered-dither array for a component having ncolors
+ * distinct output values.
+ */
+
+LOCAL(ODITHER_MATRIX_PTR)
+make_odither_array (j_decompress_ptr cinfo, int ncolors)
+{
+ ODITHER_MATRIX_PTR odither;
+ int j,k;
+ INT32 num,den;
+
+ odither = (ODITHER_MATRIX_PTR)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(ODITHER_MATRIX));
+ /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1).
+ * Hence the dither value for the matrix cell with fill order f
+ * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1).
+ * On 16-bit-int machine, be careful to avoid overflow.
+ */
+ den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1));
+ for (j = 0; j < ODITHER_SIZE; j++) {
+ for (k = 0; k < ODITHER_SIZE; k++) {
+ num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k])))
+ * MAXJSAMPLE;
+ /* Ensure round towards zero despite C's lack of consistency
+ * about rounding negative values in integer division...
+ */
+ odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den);
+ }
+ }
+ return odither;
+}
+
+
+/*
+ * Create the ordered-dither tables.
+ * Components having the same number of representative colors may
+ * share a dither table.
+ */
+
+LOCAL(void)
+create_odither_tables (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ ODITHER_MATRIX_PTR odither;
+ int i, j, nci;
+
+ for (i = 0; i < cinfo->out_color_components; i++) {
+ nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
+ odither = NULL; /* search for matching prior component */
+ for (j = 0; j < i; j++) {
+ if (nci == cquantize->Ncolors[j]) {
+ odither = cquantize->odither[j];
+ break;
+ }
+ }
+ if (odither == NULL) /* need a new table? */
+ odither = make_odither_array(cinfo, nci);
+ cquantize->odither[i] = odither;
+ }
+}
+
+
+/*
+ * Map some rows of pixels to the output colormapped representation.
+ */
+
+METHODDEF(void)
+color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+ JSAMPARRAY output_buf, int num_rows)
+/* General case, no dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ JSAMPARRAY colorindex = cquantize->colorindex;
+ register int pixcode, ci;
+ register JSAMPROW ptrin, ptrout;
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+ register int nc = cinfo->out_color_components;
+
+ for (row = 0; row < num_rows; row++) {
+ ptrin = input_buf[row];
+ ptrout = output_buf[row];
+ for (col = width; col > 0; col--) {
+ pixcode = 0;
+ for (ci = 0; ci < nc; ci++) {
+ pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]);
+ }
+ *ptrout++ = (JSAMPLE) pixcode;
+ }
+ }
+}
+
+
+METHODDEF(void)
+color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+ JSAMPARRAY output_buf, int num_rows)
+/* Fast path for out_color_components==3, no dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ register int pixcode;
+ register JSAMPROW ptrin, ptrout;
+ JSAMPROW colorindex0 = cquantize->colorindex[0];
+ JSAMPROW colorindex1 = cquantize->colorindex[1];
+ JSAMPROW colorindex2 = cquantize->colorindex[2];
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+
+ for (row = 0; row < num_rows; row++) {
+ ptrin = input_buf[row];
+ ptrout = output_buf[row];
+ for (col = width; col > 0; col--) {
+ pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]);
+ pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]);
+ pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]);
+ *ptrout++ = (JSAMPLE) pixcode;
+ }
+ }
+}
+
+
+METHODDEF(void)
+quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+ JSAMPARRAY output_buf, int num_rows)
+/* General case, with ordered dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ register JSAMPROW input_ptr;
+ register JSAMPROW output_ptr;
+ JSAMPROW colorindex_ci;
+ int * dither; /* points to active row of dither matrix */
+ int row_index, col_index; /* current indexes into dither matrix */
+ int nc = cinfo->out_color_components;
+ int ci;
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+
+ for (row = 0; row < num_rows; row++) {
+ /* Initialize output values to 0 so can process components separately */
+ jzero_far((void FAR *) output_buf[row],
+ (size_t) (width * SIZEOF(JSAMPLE)));
+ row_index = cquantize->row_index;
+ for (ci = 0; ci < nc; ci++) {
+ input_ptr = input_buf[row] + ci;
+ output_ptr = output_buf[row];
+ colorindex_ci = cquantize->colorindex[ci];
+ dither = cquantize->odither[ci][row_index];
+ col_index = 0;
+
+ for (col = width; col > 0; col--) {
+ /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE,
+ * select output value, accumulate into output code for this pixel.
+ * Range-limiting need not be done explicitly, as we have extended
+ * the colorindex table to produce the right answers for out-of-range
+ * inputs. The maximum dither is +- MAXJSAMPLE; this sets the
+ * required amount of padding.
+ */
+ *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]];
+ input_ptr += nc;
+ output_ptr++;
+ col_index = (col_index + 1) & ODITHER_MASK;
+ }
+ }
+ /* Advance row index for next row */
+ row_index = (row_index + 1) & ODITHER_MASK;
+ cquantize->row_index = row_index;
+ }
+}
+
+
+METHODDEF(void)
+quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+ JSAMPARRAY output_buf, int num_rows)
+/* Fast path for out_color_components==3, with ordered dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ register int pixcode;
+ register JSAMPROW input_ptr;
+ register JSAMPROW output_ptr;
+ JSAMPROW colorindex0 = cquantize->colorindex[0];
+ JSAMPROW colorindex1 = cquantize->colorindex[1];
+ JSAMPROW colorindex2 = cquantize->colorindex[2];
+ int * dither0; /* points to active row of dither matrix */
+ int * dither1;
+ int * dither2;
+ int row_index, col_index; /* current indexes into dither matrix */
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+
+ for (row = 0; row < num_rows; row++) {
+ row_index = cquantize->row_index;
+ input_ptr = input_buf[row];
+ output_ptr = output_buf[row];
+ dither0 = cquantize->odither[0][row_index];
+ dither1 = cquantize->odither[1][row_index];
+ dither2 = cquantize->odither[2][row_index];
+ col_index = 0;
+
+ for (col = width; col > 0; col--) {
+ pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) +
+ dither0[col_index]]);
+ pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) +
+ dither1[col_index]]);
+ pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) +
+ dither2[col_index]]);
+ *output_ptr++ = (JSAMPLE) pixcode;
+ col_index = (col_index + 1) & ODITHER_MASK;
+ }
+ row_index = (row_index + 1) & ODITHER_MASK;
+ cquantize->row_index = row_index;
+ }
+}
+
+
+METHODDEF(void)
+quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+ JSAMPARRAY output_buf, int num_rows)
+/* General case, with Floyd-Steinberg dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ register LOCFSERROR cur; /* current error or pixel value */
+ LOCFSERROR belowerr; /* error for pixel below cur */
+ LOCFSERROR bpreverr; /* error for below/prev col */
+ LOCFSERROR bnexterr; /* error for below/next col */
+ LOCFSERROR delta;
+ register FSERRPTR errorptr; /* => fserrors[] at column before current */
+ register JSAMPROW input_ptr;
+ register JSAMPROW output_ptr;
+ JSAMPROW colorindex_ci;
+ JSAMPROW colormap_ci;
+ int pixcode;
+ int nc = cinfo->out_color_components;
+ int dir; /* 1 for left-to-right, -1 for right-to-left */
+ int dirnc; /* dir * nc */
+ int ci;
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+ JSAMPLE *range_limit = cinfo->sample_range_limit;
+ SHIFT_TEMPS
+
+ for (row = 0; row < num_rows; row++) {
+ /* Initialize output values to 0 so can process components separately */
+ jzero_far((void FAR *) output_buf[row],
+ (size_t) (width * SIZEOF(JSAMPLE)));
+ for (ci = 0; ci < nc; ci++) {
+ input_ptr = input_buf[row] + ci;
+ output_ptr = output_buf[row];
+ if (cquantize->on_odd_row) {
+ /* work right to left in this row */
+ input_ptr += (width-1) * nc; /* so point to rightmost pixel */
+ output_ptr += width-1;
+ dir = -1;
+ dirnc = -nc;
+ errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */
+ } else {
+ /* work left to right in this row */
+ dir = 1;
+ dirnc = nc;
+ errorptr = cquantize->fserrors[ci]; /* => entry before first column */
+ }
+ colorindex_ci = cquantize->colorindex[ci];
+ colormap_ci = cquantize->sv_colormap[ci];
+ /* Preset error values: no error propagated to first pixel from left */
+ cur = 0;
+ /* and no error propagated to row below yet */
+ belowerr = bpreverr = 0;
+
+ for (col = width; col > 0; col--) {
+ /* cur holds the error propagated from the previous pixel on the
+ * current line. Add the error propagated from the previous line
+ * to form the complete error correction term for this pixel, and
+ * round the error term (which is expressed * 16) to an integer.
+ * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct
+ * for either sign of the error value.
+ * Note: errorptr points to *previous* column's array entry.
+ */
+ cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4);
+ /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.
+ * The maximum error is +- MAXJSAMPLE; this sets the required size
+ * of the range_limit array.
+ */
+ cur += GETJSAMPLE(*input_ptr);
+ cur = GETJSAMPLE(range_limit[cur]);
+ /* Select output value, accumulate into output code for this pixel */
+ pixcode = GETJSAMPLE(colorindex_ci[cur]);
+ *output_ptr += (JSAMPLE) pixcode;
+ /* Compute actual representation error at this pixel */
+ /* Note: we can do this even though we don't have the final */
+ /* pixel code, because the colormap is orthogonal. */
+ cur -= GETJSAMPLE(colormap_ci[pixcode]);
+ /* Compute error fractions to be propagated to adjacent pixels.
+ * Add these into the running sums, and simultaneously shift the
+ * next-line error sums left by 1 column.
+ */
+ bnexterr = cur;
+ delta = cur * 2;
+ cur += delta; /* form error * 3 */
+ errorptr[0] = (FSERROR) (bpreverr + cur);
+ cur += delta; /* form error * 5 */
+ bpreverr = belowerr + cur;
+ belowerr = bnexterr;
+ cur += delta; /* form error * 7 */
+ /* At this point cur contains the 7/16 error value to be propagated
+ * to the next pixel on the current line, and all the errors for the
+ * next line have been shifted over. We are therefore ready to move on.
+ */
+ input_ptr += dirnc; /* advance input ptr to next column */
+ output_ptr += dir; /* advance output ptr to next column */
+ errorptr += dir; /* advance errorptr to current column */
+ }
+ /* Post-loop cleanup: we must unload the final error value into the
+ * final fserrors[] entry. Note we need not unload belowerr because
+ * it is for the dummy column before or after the actual array.
+ */
+ errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */
+ }
+ cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE);
+ }
+}
+
+
+/*
+ * Allocate workspace for Floyd-Steinberg errors.
+ */
+
+LOCAL(void)
+alloc_fs_workspace (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ size_t arraysize;
+ int i;
+
+ arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
+ for (i = 0; i < cinfo->out_color_components; i++) {
+ cquantize->fserrors[i] = (FSERRPTR)
+ (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);
+ }
+}
+
+
+/*
+ * Initialize for one-pass color quantization.
+ */
+
+METHODDEF(void)
+start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ size_t arraysize;
+ int i;
+ (void)is_pre_scan;
+
+ /* Install my colormap. */
+ cinfo->colormap = cquantize->sv_colormap;
+ cinfo->actual_number_of_colors = cquantize->sv_actual;
+
+ /* Initialize for desired dithering mode. */
+ switch (cinfo->dither_mode) {
+ case JDITHER_NONE:
+ if (cinfo->out_color_components == 3)
+ cquantize->pub.color_quantize = color_quantize3;
+ else
+ cquantize->pub.color_quantize = color_quantize;
+ break;
+ case JDITHER_ORDERED:
+ if (cinfo->out_color_components == 3)
+ cquantize->pub.color_quantize = quantize3_ord_dither;
+ else
+ cquantize->pub.color_quantize = quantize_ord_dither;
+ cquantize->row_index = 0; /* initialize state for ordered dither */
+ /* If user changed to ordered dither from another mode,
+ * we must recreate the color index table with padding.
+ * This will cost extra space, but probably isn't very likely.
+ */
+ if (! cquantize->is_padded)
+ create_colorindex(cinfo);
+ /* Create ordered-dither tables if we didn't already. */
+ if (cquantize->odither[0] == NULL)
+ create_odither_tables(cinfo);
+ break;
+ case JDITHER_FS:
+ cquantize->pub.color_quantize = quantize_fs_dither;
+ cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */
+ /* Allocate Floyd-Steinberg workspace if didn't already. */
+ if (cquantize->fserrors[0] == NULL)
+ alloc_fs_workspace(cinfo);
+ /* Initialize the propagated errors to zero. */
+ arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
+ for (i = 0; i < cinfo->out_color_components; i++)
+ jzero_far((void FAR *) cquantize->fserrors[i], arraysize);
+ break;
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+}
+
+
+/*
+ * Finish up at the end of the pass.
+ */
+
+METHODDEF(void)
+finish_pass_1_quant (j_decompress_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work in 1-pass case */
+}
+
+
+/*
+ * Switch to a new external colormap between output passes.
+ * Shouldn't get to this module!
+ */
+
+METHODDEF(void)
+new_color_map_1_quant (j_decompress_ptr cinfo)
+{
+ ERREXIT(cinfo, JERR_MODE_CHANGE);
+}
+
+
+/*
+ * Module initialization routine for 1-pass color quantization.
+ */
+
+GLOBAL(void)
+jinit_1pass_quantizer (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize;
+
+ cquantize = (my_cquantize_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_cquantizer));
+ cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;
+ cquantize->pub.start_pass = start_pass_1_quant;
+ cquantize->pub.finish_pass = finish_pass_1_quant;
+ cquantize->pub.new_color_map = new_color_map_1_quant;
+ cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */
+ cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */
+
+ /* Make sure my internal arrays won't overflow */
+ if (cinfo->out_color_components > MAX_Q_COMPS)
+ ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS);
+ /* Make sure colormap indexes can be represented by JSAMPLEs */
+ if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))
+ ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1);
+
+ /* Create the colormap and color index table. */
+ create_colormap(cinfo);
+ create_colorindex(cinfo);
+
+ /* Allocate Floyd-Steinberg workspace now if requested.
+ * We do this now since it is FAR storage and may affect the memory
+ * manager's space calculations. If the user changes to FS dither
+ * mode in a later pass, we will allocate the space then, and will
+ * possibly overrun the max_memory_to_use setting.
+ */
+ if (cinfo->dither_mode == JDITHER_FS)
+ alloc_fs_workspace(cinfo);
+}
+
+#endif /* QUANT_1PASS_SUPPORTED */
--- /dev/null
+/*
+ * jquant2.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains 2-pass color quantization (color mapping) routines.
+ * These routines provide selection of a custom color map for an image,
+ * followed by mapping of the image to that color map, with optional
+ * Floyd-Steinberg dithering.
+ * It is also possible to use just the second pass to map to an arbitrary
+ * externally-given color map.
+ *
+ * Note: ordered dithering is not supported, since there isn't any fast
+ * way to compute intercolor distances; it's unclear that ordered dither's
+ * fundamental assumptions even hold with an irregularly spaced color map.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+#ifdef QUANT_2PASS_SUPPORTED
+
+
+/*
+ * This module implements the well-known Heckbert paradigm for color
+ * quantization. Most of the ideas used here can be traced back to
+ * Heckbert's seminal paper
+ * Heckbert, Paul. "Color Image Quantization for Frame Buffer Display",
+ * Proc. SIGGRAPH '82, Computer Graphics v.16 #3 (July 1982), pp 297-304.
+ *
+ * In the first pass over the image, we accumulate a histogram showing the
+ * usage count of each possible color. To keep the histogram to a reasonable
+ * size, we reduce the precision of the input; typical practice is to retain
+ * 5 or 6 bits per color, so that 8 or 4 different input values are counted
+ * in the same histogram cell.
+ *
+ * Next, the color-selection step begins with a box representing the whole
+ * color space, and repeatedly splits the "largest" remaining box until we
+ * have as many boxes as desired colors. Then the mean color in each
+ * remaining box becomes one of the possible output colors.
+ *
+ * The second pass over the image maps each input pixel to the closest output
+ * color (optionally after applying a Floyd-Steinberg dithering correction).
+ * This mapping is logically trivial, but making it go fast enough requires
+ * considerable care.
+ *
+ * Heckbert-style quantizers vary a good deal in their policies for choosing
+ * the "largest" box and deciding where to cut it. The particular policies
+ * used here have proved out well in experimental comparisons, but better ones
+ * may yet be found.
+ *
+ * In earlier versions of the IJG code, this module quantized in YCbCr color
+ * space, processing the raw upsampled data without a color conversion step.
+ * This allowed the color conversion math to be done only once per colormap
+ * entry, not once per pixel. However, that optimization precluded other
+ * useful optimizations (such as merging color conversion with upsampling)
+ * and it also interfered with desired capabilities such as quantizing to an
+ * externally-supplied colormap. We have therefore abandoned that approach.
+ * The present code works in the post-conversion color space, typically RGB.
+ *
+ * To improve the visual quality of the results, we actually work in scaled
+ * RGB space, giving G distances more weight than R, and R in turn more than
+ * B. To do everything in integer math, we must use integer scale factors.
+ * The 2/3/1 scale factors used here correspond loosely to the relative
+ * weights of the colors in the NTSC grayscale equation.
+ * If you want to use this code to quantize a non-RGB color space, you'll
+ * probably need to change these scale factors.
+ */
+
+#define R_SCALE 2 /* scale R distances by this much */
+#define G_SCALE 3 /* scale G distances by this much */
+#define B_SCALE 1 /* and B by this much */
+
+/* Relabel R/G/B as components 0/1/2, respecting the RGB ordering defined
+ * in jmorecfg.h. As the code stands, it will do the right thing for R,G,B
+ * and B,G,R orders. If you define some other weird order in jmorecfg.h,
+ * you'll get compile errors until you extend this logic. In that case
+ * you'll probably want to tweak the histogram sizes too.
+ */
+
+#if RGB_RED == 0
+#define C0_SCALE R_SCALE
+#endif
+#if RGB_BLUE == 0
+#define C0_SCALE B_SCALE
+#endif
+#if RGB_GREEN == 1
+#define C1_SCALE G_SCALE
+#endif
+#if RGB_RED == 2
+#define C2_SCALE R_SCALE
+#endif
+#if RGB_BLUE == 2
+#define C2_SCALE B_SCALE
+#endif
+
+
+/*
+ * First we have the histogram data structure and routines for creating it.
+ *
+ * The number of bits of precision can be adjusted by changing these symbols.
+ * We recommend keeping 6 bits for G and 5 each for R and B.
+ * If you have plenty of memory and cycles, 6 bits all around gives marginally
+ * better results; if you are short of memory, 5 bits all around will save
+ * some space but degrade the results.
+ * To maintain a fully accurate histogram, we'd need to allocate a "long"
+ * (preferably unsigned long) for each cell. In practice this is overkill;
+ * we can get by with 16 bits per cell. Few of the cell counts will overflow,
+ * and clamping those that do overflow to the maximum value will give close-
+ * enough results. This reduces the recommended histogram size from 256Kb
+ * to 128Kb, which is a useful savings on PC-class machines.
+ * (In the second pass the histogram space is re-used for pixel mapping data;
+ * in that capacity, each cell must be able to store zero to the number of
+ * desired colors. 16 bits/cell is plenty for that too.)
+ * Since the JPEG code is intended to run in small memory model on 80x86
+ * machines, we can't just allocate the histogram in one chunk. Instead
+ * of a true 3-D array, we use a row of pointers to 2-D arrays. Each
+ * pointer corresponds to a C0 value (typically 2^5 = 32 pointers) and
+ * each 2-D array has 2^6*2^5 = 2048 or 2^6*2^6 = 4096 entries. Note that
+ * on 80x86 machines, the pointer row is in near memory but the actual
+ * arrays are in far memory (same arrangement as we use for image arrays).
+ */
+
+#define MAXNUMCOLORS (MAXJSAMPLE+1) /* maximum size of colormap */
+
+/* These will do the right thing for either R,G,B or B,G,R color order,
+ * but you may not like the results for other color orders.
+ */
+#define HIST_C0_BITS 5 /* bits of precision in R/B histogram */
+#define HIST_C1_BITS 6 /* bits of precision in G histogram */
+#define HIST_C2_BITS 5 /* bits of precision in B/R histogram */
+
+/* Number of elements along histogram axes. */
+#define HIST_C0_ELEMS (1<<HIST_C0_BITS)
+#define HIST_C1_ELEMS (1<<HIST_C1_BITS)
+#define HIST_C2_ELEMS (1<<HIST_C2_BITS)
+
+/* These are the amounts to shift an input value to get a histogram index. */
+#define C0_SHIFT (BITS_IN_JSAMPLE-HIST_C0_BITS)
+#define C1_SHIFT (BITS_IN_JSAMPLE-HIST_C1_BITS)
+#define C2_SHIFT (BITS_IN_JSAMPLE-HIST_C2_BITS)
+
+
+typedef UINT16 histcell; /* histogram cell; prefer an unsigned type */
+
+typedef histcell FAR * histptr; /* for pointers to histogram cells */
+
+typedef histcell hist1d[HIST_C2_ELEMS]; /* typedefs for the array */
+typedef hist1d FAR * hist2d; /* type for the 2nd-level pointers */
+typedef hist2d * hist3d; /* type for top-level pointer */
+
+
+/* Declarations for Floyd-Steinberg dithering.
+ *
+ * Errors are accumulated into the array fserrors[], at a resolution of
+ * 1/16th of a pixel count. The error at a given pixel is propagated
+ * to its not-yet-processed neighbors using the standard F-S fractions,
+ * ... (here) 7/16
+ * 3/16 5/16 1/16
+ * We work left-to-right on even rows, right-to-left on odd rows.
+ *
+ * We can get away with a single array (holding one row's worth of errors)
+ * by using it to store the current row's errors at pixel columns not yet
+ * processed, but the next row's errors at columns already processed. We
+ * need only a few extra variables to hold the errors immediately around the
+ * current column. (If we are lucky, those variables are in registers, but
+ * even if not, they're probably cheaper to access than array elements are.)
+ *
+ * The fserrors[] array has (#columns + 2) entries; the extra entry at
+ * each end saves us from special-casing the first and last pixels.
+ * Each entry is three values long, one value for each color component.
+ *
+ * Note: on a wide image, we might not have enough room in a PC's near data
+ * segment to hold the error array; so it is allocated with alloc_large.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+typedef INT16 FSERROR; /* 16 bits should be enough */
+typedef int LOCFSERROR; /* use 'int' for calculation temps */
+#else
+typedef INT32 FSERROR; /* may need more than 16 bits */
+typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */
+#endif
+
+typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */
+
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_color_quantizer pub; /* public fields */
+
+ /* Space for the eventually created colormap is stashed here */
+ JSAMPARRAY sv_colormap; /* colormap allocated at init time */
+ int desired; /* desired # of colors = size of colormap */
+
+ /* Variables for accumulating image statistics */
+ hist3d histogram; /* pointer to the histogram */
+
+ boolean needs_zeroed; /* TRUE if next pass must zero histogram */
+
+ /* Variables for Floyd-Steinberg dithering */
+ FSERRPTR fserrors; /* accumulated errors */
+ boolean on_odd_row; /* flag to remember which row we are on */
+ int * error_limiter; /* table for clamping the applied error */
+} my_cquantizer;
+
+typedef my_cquantizer * my_cquantize_ptr;
+
+
+/*
+ * Prescan some rows of pixels.
+ * In this module the prescan simply updates the histogram, which has been
+ * initialized to zeroes by start_pass.
+ * An output_buf parameter is required by the method signature, but no data
+ * is actually output (in fact the buffer controller is probably passing a
+ * NULL pointer).
+ */
+
+METHODDEF(void)
+prescan_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ register JSAMPROW ptr;
+ register histptr histp;
+ register hist3d histogram = cquantize->histogram;
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+ (void)output_buf;
+
+ for (row = 0; row < num_rows; row++) {
+ ptr = input_buf[row];
+ for (col = width; col > 0; col--) {
+ /* get pixel value and index into the histogram */
+ histp = & histogram[GETJSAMPLE(ptr[0]) >> C0_SHIFT]
+ [GETJSAMPLE(ptr[1]) >> C1_SHIFT]
+ [GETJSAMPLE(ptr[2]) >> C2_SHIFT];
+ /* increment, check for overflow and undo increment if so. */
+ if (++(*histp) <= 0)
+ (*histp)--;
+ ptr += 3;
+ }
+ }
+}
+
+
+/*
+ * Next we have the really interesting routines: selection of a colormap
+ * given the completed histogram.
+ * These routines work with a list of "boxes", each representing a rectangular
+ * subset of the input color space (to histogram precision).
+ */
+
+typedef struct {
+ /* The bounds of the box (inclusive); expressed as histogram indexes */
+ int c0min, c0max;
+ int c1min, c1max;
+ int c2min, c2max;
+ /* The volume (actually 2-norm) of the box */
+ INT32 volume;
+ /* The number of nonzero histogram cells within this box */
+ long colorcount;
+} box;
+
+typedef box * boxptr;
+
+
+LOCAL(boxptr)
+find_biggest_color_pop (boxptr boxlist, int numboxes)
+/* Find the splittable box with the largest color population */
+/* Returns NULL if no splittable boxes remain */
+{
+ register boxptr boxp;
+ register int i;
+ register long maxc = 0;
+ boxptr which = NULL;
+
+ for (i = 0, boxp = boxlist; i < numboxes; i++, boxp++) {
+ if (boxp->colorcount > maxc && boxp->volume > 0) {
+ which = boxp;
+ maxc = boxp->colorcount;
+ }
+ }
+ return which;
+}
+
+
+LOCAL(boxptr)
+find_biggest_volume (boxptr boxlist, int numboxes)
+/* Find the splittable box with the largest (scaled) volume */
+/* Returns NULL if no splittable boxes remain */
+{
+ register boxptr boxp;
+ register int i;
+ register INT32 maxv = 0;
+ boxptr which = NULL;
+
+ for (i = 0, boxp = boxlist; i < numboxes; i++, boxp++) {
+ if (boxp->volume > maxv) {
+ which = boxp;
+ maxv = boxp->volume;
+ }
+ }
+ return which;
+}
+
+
+LOCAL(void)
+update_box (j_decompress_ptr cinfo, boxptr boxp)
+/* Shrink the min/max bounds of a box to enclose only nonzero elements, */
+/* and recompute its volume and population */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ hist3d histogram = cquantize->histogram;
+ histptr histp;
+ int c0,c1,c2;
+ int c0min,c0max,c1min,c1max,c2min,c2max;
+ INT32 dist0,dist1,dist2;
+ long ccount;
+
+ c0min = boxp->c0min; c0max = boxp->c0max;
+ c1min = boxp->c1min; c1max = boxp->c1max;
+ c2min = boxp->c2min; c2max = boxp->c2max;
+
+ if (c0max > c0min)
+ for (c0 = c0min; c0 <= c0max; c0++)
+ for (c1 = c1min; c1 <= c1max; c1++) {
+ histp = & histogram[c0][c1][c2min];
+ for (c2 = c2min; c2 <= c2max; c2++)
+ if (*histp++ != 0) {
+ boxp->c0min = c0min = c0;
+ goto have_c0min;
+ }
+ }
+ have_c0min:
+ if (c0max > c0min)
+ for (c0 = c0max; c0 >= c0min; c0--)
+ for (c1 = c1min; c1 <= c1max; c1++) {
+ histp = & histogram[c0][c1][c2min];
+ for (c2 = c2min; c2 <= c2max; c2++)
+ if (*histp++ != 0) {
+ boxp->c0max = c0max = c0;
+ goto have_c0max;
+ }
+ }
+ have_c0max:
+ if (c1max > c1min)
+ for (c1 = c1min; c1 <= c1max; c1++)
+ for (c0 = c0min; c0 <= c0max; c0++) {
+ histp = & histogram[c0][c1][c2min];
+ for (c2 = c2min; c2 <= c2max; c2++)
+ if (*histp++ != 0) {
+ boxp->c1min = c1min = c1;
+ goto have_c1min;
+ }
+ }
+ have_c1min:
+ if (c1max > c1min)
+ for (c1 = c1max; c1 >= c1min; c1--)
+ for (c0 = c0min; c0 <= c0max; c0++) {
+ histp = & histogram[c0][c1][c2min];
+ for (c2 = c2min; c2 <= c2max; c2++)
+ if (*histp++ != 0) {
+ boxp->c1max = c1max = c1;
+ goto have_c1max;
+ }
+ }
+ have_c1max:
+ if (c2max > c2min)
+ for (c2 = c2min; c2 <= c2max; c2++)
+ for (c0 = c0min; c0 <= c0max; c0++) {
+ histp = & histogram[c0][c1min][c2];
+ for (c1 = c1min; c1 <= c1max; c1++, histp += HIST_C2_ELEMS)
+ if (*histp != 0) {
+ boxp->c2min = c2min = c2;
+ goto have_c2min;
+ }
+ }
+ have_c2min:
+ if (c2max > c2min)
+ for (c2 = c2max; c2 >= c2min; c2--)
+ for (c0 = c0min; c0 <= c0max; c0++) {
+ histp = & histogram[c0][c1min][c2];
+ for (c1 = c1min; c1 <= c1max; c1++, histp += HIST_C2_ELEMS)
+ if (*histp != 0) {
+ boxp->c2max = c2max = c2;
+ goto have_c2max;
+ }
+ }
+ have_c2max:
+
+ /* Update box volume.
+ * We use 2-norm rather than real volume here; this biases the method
+ * against making long narrow boxes, and it has the side benefit that
+ * a box is splittable iff norm > 0.
+ * Since the differences are expressed in histogram-cell units,
+ * we have to shift back to JSAMPLE units to get consistent distances;
+ * after which, we scale according to the selected distance scale factors.
+ */
+ dist0 = ((c0max - c0min) << C0_SHIFT) * C0_SCALE;
+ dist1 = ((c1max - c1min) << C1_SHIFT) * C1_SCALE;
+ dist2 = ((c2max - c2min) << C2_SHIFT) * C2_SCALE;
+ boxp->volume = dist0*dist0 + dist1*dist1 + dist2*dist2;
+
+ /* Now scan remaining volume of box and compute population */
+ ccount = 0;
+ for (c0 = c0min; c0 <= c0max; c0++)
+ for (c1 = c1min; c1 <= c1max; c1++) {
+ histp = & histogram[c0][c1][c2min];
+ for (c2 = c2min; c2 <= c2max; c2++, histp++)
+ if (*histp != 0) {
+ ccount++;
+ }
+ }
+ boxp->colorcount = ccount;
+}
+
+
+LOCAL(int)
+median_cut (j_decompress_ptr cinfo, boxptr boxlist, int numboxes,
+ int desired_colors)
+/* Repeatedly select and split the largest box until we have enough boxes */
+{
+ int n,lb;
+ int c0,c1,c2,cmax;
+ register boxptr b1,b2;
+
+ while (numboxes < desired_colors) {
+ /* Select box to split.
+ * Current algorithm: by population for first half, then by volume.
+ */
+ if (numboxes*2 <= desired_colors) {
+ b1 = find_biggest_color_pop(boxlist, numboxes);
+ } else {
+ b1 = find_biggest_volume(boxlist, numboxes);
+ }
+ if (b1 == NULL) /* no splittable boxes left! */
+ break;
+ b2 = &boxlist[numboxes]; /* where new box will go */
+ /* Copy the color bounds to the new box. */
+ b2->c0max = b1->c0max; b2->c1max = b1->c1max; b2->c2max = b1->c2max;
+ b2->c0min = b1->c0min; b2->c1min = b1->c1min; b2->c2min = b1->c2min;
+ /* Choose which axis to split the box on.
+ * Current algorithm: longest scaled axis.
+ * See notes in update_box about scaling distances.
+ */
+ c0 = ((b1->c0max - b1->c0min) << C0_SHIFT) * C0_SCALE;
+ c1 = ((b1->c1max - b1->c1min) << C1_SHIFT) * C1_SCALE;
+ c2 = ((b1->c2max - b1->c2min) << C2_SHIFT) * C2_SCALE;
+ /* We want to break any ties in favor of green, then red, blue last.
+ * This code does the right thing for R,G,B or B,G,R color orders only.
+ */
+#if RGB_RED == 0
+ cmax = c1; n = 1;
+ if (c0 > cmax) { cmax = c0; n = 0; }
+ if (c2 > cmax) { n = 2; }
+#else
+ cmax = c1; n = 1;
+ if (c2 > cmax) { cmax = c2; n = 2; }
+ if (c0 > cmax) { n = 0; }
+#endif
+ /* Choose split point along selected axis, and update box bounds.
+ * Current algorithm: split at halfway point.
+ * (Since the box has been shrunk to minimum volume,
+ * any split will produce two nonempty subboxes.)
+ * Note that lb value is max for lower box, so must be < old max.
+ */
+ switch (n) {
+ case 0:
+ lb = (b1->c0max + b1->c0min) / 2;
+ b1->c0max = lb;
+ b2->c0min = lb+1;
+ break;
+ case 1:
+ lb = (b1->c1max + b1->c1min) / 2;
+ b1->c1max = lb;
+ b2->c1min = lb+1;
+ break;
+ case 2:
+ lb = (b1->c2max + b1->c2min) / 2;
+ b1->c2max = lb;
+ b2->c2min = lb+1;
+ break;
+ }
+ /* Update stats for boxes */
+ update_box(cinfo, b1);
+ update_box(cinfo, b2);
+ numboxes++;
+ }
+ return numboxes;
+}
+
+
+LOCAL(void)
+compute_color (j_decompress_ptr cinfo, boxptr boxp, int icolor)
+/* Compute representative color for a box, put it in colormap[icolor] */
+{
+ /* Current algorithm: mean weighted by pixels (not colors) */
+ /* Note it is important to get the rounding correct! */
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ hist3d histogram = cquantize->histogram;
+ histptr histp;
+ int c0,c1,c2;
+ int c0min,c0max,c1min,c1max,c2min,c2max;
+ long count;
+ long total = 0;
+ long c0total = 0;
+ long c1total = 0;
+ long c2total = 0;
+
+ c0min = boxp->c0min; c0max = boxp->c0max;
+ c1min = boxp->c1min; c1max = boxp->c1max;
+ c2min = boxp->c2min; c2max = boxp->c2max;
+
+ for (c0 = c0min; c0 <= c0max; c0++)
+ for (c1 = c1min; c1 <= c1max; c1++) {
+ histp = & histogram[c0][c1][c2min];
+ for (c2 = c2min; c2 <= c2max; c2++) {
+ if ((count = *histp++) != 0) {
+ total += count;
+ c0total += ((c0 << C0_SHIFT) + ((1<<C0_SHIFT)>>1)) * count;
+ c1total += ((c1 << C1_SHIFT) + ((1<<C1_SHIFT)>>1)) * count;
+ c2total += ((c2 << C2_SHIFT) + ((1<<C2_SHIFT)>>1)) * count;
+ }
+ }
+ }
+
+ cinfo->colormap[0][icolor] = (JSAMPLE) ((c0total + (total>>1)) / total);
+ cinfo->colormap[1][icolor] = (JSAMPLE) ((c1total + (total>>1)) / total);
+ cinfo->colormap[2][icolor] = (JSAMPLE) ((c2total + (total>>1)) / total);
+}
+
+
+LOCAL(void)
+select_colors (j_decompress_ptr cinfo, int desired_colors)
+/* Master routine for color selection */
+{
+ boxptr boxlist;
+ int numboxes;
+ int i;
+
+ /* Allocate workspace for box list */
+ boxlist = (boxptr) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, desired_colors * SIZEOF(box));
+ /* Initialize one box containing whole space */
+ numboxes = 1;
+ boxlist[0].c0min = 0;
+ boxlist[0].c0max = MAXJSAMPLE >> C0_SHIFT;
+ boxlist[0].c1min = 0;
+ boxlist[0].c1max = MAXJSAMPLE >> C1_SHIFT;
+ boxlist[0].c2min = 0;
+ boxlist[0].c2max = MAXJSAMPLE >> C2_SHIFT;
+ /* Shrink it to actually-used volume and set its statistics */
+ update_box(cinfo, & boxlist[0]);
+ /* Perform median-cut to produce final box list */
+ numboxes = median_cut(cinfo, boxlist, numboxes, desired_colors);
+ /* Compute the representative color for each box, fill colormap */
+ for (i = 0; i < numboxes; i++)
+ compute_color(cinfo, & boxlist[i], i);
+ cinfo->actual_number_of_colors = numboxes;
+ TRACEMS1(cinfo, 1, JTRC_QUANT_SELECTED, numboxes);
+}
+
+
+/*
+ * These routines are concerned with the time-critical task of mapping input
+ * colors to the nearest color in the selected colormap.
+ *
+ * We re-use the histogram space as an "inverse color map", essentially a
+ * cache for the results of nearest-color searches. All colors within a
+ * histogram cell will be mapped to the same colormap entry, namely the one
+ * closest to the cell's center. This may not be quite the closest entry to
+ * the actual input color, but it's almost as good. A zero in the cache
+ * indicates we haven't found the nearest color for that cell yet; the array
+ * is cleared to zeroes before starting the mapping pass. When we find the
+ * nearest color for a cell, its colormap index plus one is recorded in the
+ * cache for future use. The pass2 scanning routines call fill_inverse_cmap
+ * when they need to use an unfilled entry in the cache.
+ *
+ * Our method of efficiently finding nearest colors is based on the "locally
+ * sorted search" idea described by Heckbert and on the incremental distance
+ * calculation described by Spencer W. Thomas in chapter III.1 of Graphics
+ * Gems II (James Arvo, ed. Academic Press, 1991). Thomas points out that
+ * the distances from a given colormap entry to each cell of the histogram can
+ * be computed quickly using an incremental method: the differences between
+ * distances to adjacent cells themselves differ by a constant. This allows a
+ * fairly fast implementation of the "brute force" approach of computing the
+ * distance from every colormap entry to every histogram cell. Unfortunately,
+ * it needs a work array to hold the best-distance-so-far for each histogram
+ * cell (because the inner loop has to be over cells, not colormap entries).
+ * The work array elements have to be INT32s, so the work array would need
+ * 256Kb at our recommended precision. This is not feasible in DOS machines.
+ *
+ * To get around these problems, we apply Thomas' method to compute the
+ * nearest colors for only the cells within a small subbox of the histogram.
+ * The work array need be only as big as the subbox, so the memory usage
+ * problem is solved. Furthermore, we need not fill subboxes that are never
+ * referenced in pass2; many images use only part of the color gamut, so a
+ * fair amount of work is saved. An additional advantage of this
+ * approach is that we can apply Heckbert's locality criterion to quickly
+ * eliminate colormap entries that are far away from the subbox; typically
+ * three-fourths of the colormap entries are rejected by Heckbert's criterion,
+ * and we need not compute their distances to individual cells in the subbox.
+ * The speed of this approach is heavily influenced by the subbox size: too
+ * small means too much overhead, too big loses because Heckbert's criterion
+ * can't eliminate as many colormap entries. Empirically the best subbox
+ * size seems to be about 1/512th of the histogram (1/8th in each direction).
+ *
+ * Thomas' article also describes a refined method which is asymptotically
+ * faster than the brute-force method, but it is also far more complex and
+ * cannot efficiently be applied to small subboxes. It is therefore not
+ * useful for programs intended to be portable to DOS machines. On machines
+ * with plenty of memory, filling the whole histogram in one shot with Thomas'
+ * refined method might be faster than the present code --- but then again,
+ * it might not be any faster, and it's certainly more complicated.
+ */
+
+
+/* log2(histogram cells in update box) for each axis; this can be adjusted */
+#define BOX_C0_LOG (HIST_C0_BITS-3)
+#define BOX_C1_LOG (HIST_C1_BITS-3)
+#define BOX_C2_LOG (HIST_C2_BITS-3)
+
+#define BOX_C0_ELEMS (1<<BOX_C0_LOG) /* # of hist cells in update box */
+#define BOX_C1_ELEMS (1<<BOX_C1_LOG)
+#define BOX_C2_ELEMS (1<<BOX_C2_LOG)
+
+#define BOX_C0_SHIFT (C0_SHIFT + BOX_C0_LOG)
+#define BOX_C1_SHIFT (C1_SHIFT + BOX_C1_LOG)
+#define BOX_C2_SHIFT (C2_SHIFT + BOX_C2_LOG)
+
+
+/*
+ * The next three routines implement inverse colormap filling. They could
+ * all be folded into one big routine, but splitting them up this way saves
+ * some stack space (the mindist[] and bestdist[] arrays need not coexist)
+ * and may allow some compilers to produce better code by registerizing more
+ * inner-loop variables.
+ */
+
+LOCAL(int)
+find_nearby_colors (j_decompress_ptr cinfo, int minc0, int minc1, int minc2,
+ JSAMPLE colorlist[])
+/* Locate the colormap entries close enough to an update box to be candidates
+ * for the nearest entry to some cell(s) in the update box. The update box
+ * is specified by the center coordinates of its first cell. The number of
+ * candidate colormap entries is returned, and their colormap indexes are
+ * placed in colorlist[].
+ * This routine uses Heckbert's "locally sorted search" criterion to select
+ * the colors that need further consideration.
+ */
+{
+ int numcolors = cinfo->actual_number_of_colors;
+ int maxc0, maxc1, maxc2;
+ int centerc0, centerc1, centerc2;
+ int i, x, ncolors;
+ INT32 minmaxdist, min_dist, max_dist, tdist;
+ INT32 mindist[MAXNUMCOLORS]; /* min distance to colormap entry i */
+
+ /* Compute true coordinates of update box's upper corner and center.
+ * Actually we compute the coordinates of the center of the upper-corner
+ * histogram cell, which are the upper bounds of the volume we care about.
+ * Note that since ">>" rounds down, the "center" values may be closer to
+ * min than to max; hence comparisons to them must be "<=", not "<".
+ */
+ maxc0 = minc0 + ((1 << BOX_C0_SHIFT) - (1 << C0_SHIFT));
+ centerc0 = (minc0 + maxc0) >> 1;
+ maxc1 = minc1 + ((1 << BOX_C1_SHIFT) - (1 << C1_SHIFT));
+ centerc1 = (minc1 + maxc1) >> 1;
+ maxc2 = minc2 + ((1 << BOX_C2_SHIFT) - (1 << C2_SHIFT));
+ centerc2 = (minc2 + maxc2) >> 1;
+
+ /* For each color in colormap, find:
+ * 1. its minimum squared-distance to any point in the update box
+ * (zero if color is within update box);
+ * 2. its maximum squared-distance to any point in the update box.
+ * Both of these can be found by considering only the corners of the box.
+ * We save the minimum distance for each color in mindist[];
+ * only the smallest maximum distance is of interest.
+ */
+ minmaxdist = 0x7FFFFFFFL;
+
+ for (i = 0; i < numcolors; i++) {
+ /* We compute the squared-c0-distance term, then add in the other two. */
+ x = GETJSAMPLE(cinfo->colormap[0][i]);
+ if (x < minc0) {
+ tdist = (x - minc0) * C0_SCALE;
+ min_dist = tdist*tdist;
+ tdist = (x - maxc0) * C0_SCALE;
+ max_dist = tdist*tdist;
+ } else if (x > maxc0) {
+ tdist = (x - maxc0) * C0_SCALE;
+ min_dist = tdist*tdist;
+ tdist = (x - minc0) * C0_SCALE;
+ max_dist = tdist*tdist;
+ } else {
+ /* within cell range so no contribution to min_dist */
+ min_dist = 0;
+ if (x <= centerc0) {
+ tdist = (x - maxc0) * C0_SCALE;
+ max_dist = tdist*tdist;
+ } else {
+ tdist = (x - minc0) * C0_SCALE;
+ max_dist = tdist*tdist;
+ }
+ }
+
+ x = GETJSAMPLE(cinfo->colormap[1][i]);
+ if (x < minc1) {
+ tdist = (x - minc1) * C1_SCALE;
+ min_dist += tdist*tdist;
+ tdist = (x - maxc1) * C1_SCALE;
+ max_dist += tdist*tdist;
+ } else if (x > maxc1) {
+ tdist = (x - maxc1) * C1_SCALE;
+ min_dist += tdist*tdist;
+ tdist = (x - minc1) * C1_SCALE;
+ max_dist += tdist*tdist;
+ } else {
+ /* within cell range so no contribution to min_dist */
+ if (x <= centerc1) {
+ tdist = (x - maxc1) * C1_SCALE;
+ max_dist += tdist*tdist;
+ } else {
+ tdist = (x - minc1) * C1_SCALE;
+ max_dist += tdist*tdist;
+ }
+ }
+
+ x = GETJSAMPLE(cinfo->colormap[2][i]);
+ if (x < minc2) {
+ tdist = (x - minc2) * C2_SCALE;
+ min_dist += tdist*tdist;
+ tdist = (x - maxc2) * C2_SCALE;
+ max_dist += tdist*tdist;
+ } else if (x > maxc2) {
+ tdist = (x - maxc2) * C2_SCALE;
+ min_dist += tdist*tdist;
+ tdist = (x - minc2) * C2_SCALE;
+ max_dist += tdist*tdist;
+ } else {
+ /* within cell range so no contribution to min_dist */
+ if (x <= centerc2) {
+ tdist = (x - maxc2) * C2_SCALE;
+ max_dist += tdist*tdist;
+ } else {
+ tdist = (x - minc2) * C2_SCALE;
+ max_dist += tdist*tdist;
+ }
+ }
+
+ mindist[i] = min_dist; /* save away the results */
+ if (max_dist < minmaxdist)
+ minmaxdist = max_dist;
+ }
+
+ /* Now we know that no cell in the update box is more than minmaxdist
+ * away from some colormap entry. Therefore, only colors that are
+ * within minmaxdist of some part of the box need be considered.
+ */
+ ncolors = 0;
+ for (i = 0; i < numcolors; i++) {
+ if (mindist[i] <= minmaxdist)
+ colorlist[ncolors++] = (JSAMPLE) i;
+ }
+ return ncolors;
+}
+
+
+LOCAL(void)
+find_best_colors (j_decompress_ptr cinfo, int minc0, int minc1, int minc2,
+ int numcolors, JSAMPLE colorlist[], JSAMPLE bestcolor[])
+/* Find the closest colormap entry for each cell in the update box,
+ * given the list of candidate colors prepared by find_nearby_colors.
+ * Return the indexes of the closest entries in the bestcolor[] array.
+ * This routine uses Thomas' incremental distance calculation method to
+ * find the distance from a colormap entry to successive cells in the box.
+ */
+{
+ int ic0, ic1, ic2;
+ int i, icolor;
+ register INT32 * bptr; /* pointer into bestdist[] array */
+ JSAMPLE * cptr; /* pointer into bestcolor[] array */
+ INT32 dist0, dist1; /* initial distance values */
+ register INT32 dist2; /* current distance in inner loop */
+ INT32 xx0, xx1; /* distance increments */
+ register INT32 xx2;
+ INT32 inc0, inc1, inc2; /* initial values for increments */
+ /* This array holds the distance to the nearest-so-far color for each cell */
+ INT32 bestdist[BOX_C0_ELEMS * BOX_C1_ELEMS * BOX_C2_ELEMS];
+
+ /* Initialize best-distance for each cell of the update box */
+ bptr = bestdist;
+ for (i = BOX_C0_ELEMS*BOX_C1_ELEMS*BOX_C2_ELEMS-1; i >= 0; i--)
+ *bptr++ = 0x7FFFFFFFL;
+
+ /* For each color selected by find_nearby_colors,
+ * compute its distance to the center of each cell in the box.
+ * If that's less than best-so-far, update best distance and color number.
+ */
+
+ /* Nominal steps between cell centers ("x" in Thomas article) */
+#define STEP_C0 ((1 << C0_SHIFT) * C0_SCALE)
+#define STEP_C1 ((1 << C1_SHIFT) * C1_SCALE)
+#define STEP_C2 ((1 << C2_SHIFT) * C2_SCALE)
+
+ for (i = 0; i < numcolors; i++) {
+ icolor = GETJSAMPLE(colorlist[i]);
+ /* Compute (square of) distance from minc0/c1/c2 to this color */
+ inc0 = (minc0 - GETJSAMPLE(cinfo->colormap[0][icolor])) * C0_SCALE;
+ dist0 = inc0*inc0;
+ inc1 = (minc1 - GETJSAMPLE(cinfo->colormap[1][icolor])) * C1_SCALE;
+ dist0 += inc1*inc1;
+ inc2 = (minc2 - GETJSAMPLE(cinfo->colormap[2][icolor])) * C2_SCALE;
+ dist0 += inc2*inc2;
+ /* Form the initial difference increments */
+ inc0 = inc0 * (2 * STEP_C0) + STEP_C0 * STEP_C0;
+ inc1 = inc1 * (2 * STEP_C1) + STEP_C1 * STEP_C1;
+ inc2 = inc2 * (2 * STEP_C2) + STEP_C2 * STEP_C2;
+ /* Now loop over all cells in box, updating distance per Thomas method */
+ bptr = bestdist;
+ cptr = bestcolor;
+ xx0 = inc0;
+ for (ic0 = BOX_C0_ELEMS-1; ic0 >= 0; ic0--) {
+ dist1 = dist0;
+ xx1 = inc1;
+ for (ic1 = BOX_C1_ELEMS-1; ic1 >= 0; ic1--) {
+ dist2 = dist1;
+ xx2 = inc2;
+ for (ic2 = BOX_C2_ELEMS-1; ic2 >= 0; ic2--) {
+ if (dist2 < *bptr) {
+ *bptr = dist2;
+ *cptr = (JSAMPLE) icolor;
+ }
+ dist2 += xx2;
+ xx2 += 2 * STEP_C2 * STEP_C2;
+ bptr++;
+ cptr++;
+ }
+ dist1 += xx1;
+ xx1 += 2 * STEP_C1 * STEP_C1;
+ }
+ dist0 += xx0;
+ xx0 += 2 * STEP_C0 * STEP_C0;
+ }
+ }
+}
+
+
+LOCAL(void)
+fill_inverse_cmap (j_decompress_ptr cinfo, int c0, int c1, int c2)
+/* Fill the inverse-colormap entries in the update box that contains */
+/* histogram cell c0/c1/c2. (Only that one cell MUST be filled, but */
+/* we can fill as many others as we wish.) */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ hist3d histogram = cquantize->histogram;
+ int minc0, minc1, minc2; /* lower left corner of update box */
+ int ic0, ic1, ic2;
+ register JSAMPLE * cptr; /* pointer into bestcolor[] array */
+ register histptr cachep; /* pointer into main cache array */
+ /* This array lists the candidate colormap indexes. */
+ JSAMPLE colorlist[MAXNUMCOLORS];
+ int numcolors; /* number of candidate colors */
+ /* This array holds the actually closest colormap index for each cell. */
+ JSAMPLE bestcolor[BOX_C0_ELEMS * BOX_C1_ELEMS * BOX_C2_ELEMS];
+
+ /* Convert cell coordinates to update box ID */
+ c0 >>= BOX_C0_LOG;
+ c1 >>= BOX_C1_LOG;
+ c2 >>= BOX_C2_LOG;
+
+ /* Compute true coordinates of update box's origin corner.
+ * Actually we compute the coordinates of the center of the corner
+ * histogram cell, which are the lower bounds of the volume we care about.
+ */
+ minc0 = (c0 << BOX_C0_SHIFT) + ((1 << C0_SHIFT) >> 1);
+ minc1 = (c1 << BOX_C1_SHIFT) + ((1 << C1_SHIFT) >> 1);
+ minc2 = (c2 << BOX_C2_SHIFT) + ((1 << C2_SHIFT) >> 1);
+
+ /* Determine which colormap entries are close enough to be candidates
+ * for the nearest entry to some cell in the update box.
+ */
+ numcolors = find_nearby_colors(cinfo, minc0, minc1, minc2, colorlist);
+
+ /* Determine the actually nearest colors. */
+ find_best_colors(cinfo, minc0, minc1, minc2, numcolors, colorlist,
+ bestcolor);
+
+ /* Save the best color numbers (plus 1) in the main cache array */
+ c0 <<= BOX_C0_LOG; /* convert ID back to base cell indexes */
+ c1 <<= BOX_C1_LOG;
+ c2 <<= BOX_C2_LOG;
+ cptr = bestcolor;
+ for (ic0 = 0; ic0 < BOX_C0_ELEMS; ic0++) {
+ for (ic1 = 0; ic1 < BOX_C1_ELEMS; ic1++) {
+ cachep = & histogram[c0+ic0][c1+ic1][c2];
+ for (ic2 = 0; ic2 < BOX_C2_ELEMS; ic2++) {
+ *cachep++ = (histcell) (GETJSAMPLE(*cptr++) + 1);
+ }
+ }
+ }
+}
+
+
+/*
+ * Map some rows of pixels to the output colormapped representation.
+ */
+
+METHODDEF(void)
+pass2_no_dither (j_decompress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPARRAY output_buf, int num_rows)
+/* This version performs no dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ hist3d histogram = cquantize->histogram;
+ register JSAMPROW inptr, outptr;
+ register histptr cachep;
+ register int c0, c1, c2;
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+
+ for (row = 0; row < num_rows; row++) {
+ inptr = input_buf[row];
+ outptr = output_buf[row];
+ for (col = width; col > 0; col--) {
+ /* get pixel value and index into the cache */
+ c0 = GETJSAMPLE(*inptr++) >> C0_SHIFT;
+ c1 = GETJSAMPLE(*inptr++) >> C1_SHIFT;
+ c2 = GETJSAMPLE(*inptr++) >> C2_SHIFT;
+ cachep = & histogram[c0][c1][c2];
+ /* If we have not seen this color before, find nearest colormap entry */
+ /* and update the cache */
+ if (*cachep == 0)
+ fill_inverse_cmap(cinfo, c0,c1,c2);
+ /* Now emit the colormap index for this cell */
+ *outptr++ = (JSAMPLE) (*cachep - 1);
+ }
+ }
+}
+
+
+METHODDEF(void)
+pass2_fs_dither (j_decompress_ptr cinfo,
+ JSAMPARRAY input_buf, JSAMPARRAY output_buf, int num_rows)
+/* This version performs Floyd-Steinberg dithering */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ hist3d histogram = cquantize->histogram;
+ register LOCFSERROR cur0, cur1, cur2; /* current error or pixel value */
+ LOCFSERROR belowerr0, belowerr1, belowerr2; /* error for pixel below cur */
+ LOCFSERROR bpreverr0, bpreverr1, bpreverr2; /* error for below/prev col */
+ register FSERRPTR errorptr; /* => fserrors[] at column before current */
+ JSAMPROW inptr; /* => current input pixel */
+ JSAMPROW outptr; /* => current output pixel */
+ histptr cachep;
+ int dir; /* +1 or -1 depending on direction */
+ int dir3; /* 3*dir, for advancing inptr & errorptr */
+ int row;
+ JDIMENSION col;
+ JDIMENSION width = cinfo->output_width;
+ JSAMPLE *range_limit = cinfo->sample_range_limit;
+ int *error_limit = cquantize->error_limiter;
+ JSAMPROW colormap0 = cinfo->colormap[0];
+ JSAMPROW colormap1 = cinfo->colormap[1];
+ JSAMPROW colormap2 = cinfo->colormap[2];
+ SHIFT_TEMPS
+
+ for (row = 0; row < num_rows; row++) {
+ inptr = input_buf[row];
+ outptr = output_buf[row];
+ if (cquantize->on_odd_row) {
+ /* work right to left in this row */
+ inptr += (width-1) * 3; /* so point to rightmost pixel */
+ outptr += width-1;
+ dir = -1;
+ dir3 = -3;
+ errorptr = cquantize->fserrors + (width+1)*3; /* => entry after last column */
+ cquantize->on_odd_row = FALSE; /* flip for next time */
+ } else {
+ /* work left to right in this row */
+ dir = 1;
+ dir3 = 3;
+ errorptr = cquantize->fserrors; /* => entry before first real column */
+ cquantize->on_odd_row = TRUE; /* flip for next time */
+ }
+ /* Preset error values: no error propagated to first pixel from left */
+ cur0 = cur1 = cur2 = 0;
+ /* and no error propagated to row below yet */
+ belowerr0 = belowerr1 = belowerr2 = 0;
+ bpreverr0 = bpreverr1 = bpreverr2 = 0;
+
+ for (col = width; col > 0; col--) {
+ /* curN holds the error propagated from the previous pixel on the
+ * current line. Add the error propagated from the previous line
+ * to form the complete error correction term for this pixel, and
+ * round the error term (which is expressed * 16) to an integer.
+ * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct
+ * for either sign of the error value.
+ * Note: errorptr points to *previous* column's array entry.
+ */
+ cur0 = RIGHT_SHIFT(cur0 + errorptr[dir3+0] + 8, 4);
+ cur1 = RIGHT_SHIFT(cur1 + errorptr[dir3+1] + 8, 4);
+ cur2 = RIGHT_SHIFT(cur2 + errorptr[dir3+2] + 8, 4);
+ /* Limit the error using transfer function set by init_error_limit.
+ * See comments with init_error_limit for rationale.
+ */
+ cur0 = error_limit[cur0];
+ cur1 = error_limit[cur1];
+ cur2 = error_limit[cur2];
+ /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.
+ * The maximum error is +- MAXJSAMPLE (or less with error limiting);
+ * this sets the required size of the range_limit array.
+ */
+ cur0 += GETJSAMPLE(inptr[0]);
+ cur1 += GETJSAMPLE(inptr[1]);
+ cur2 += GETJSAMPLE(inptr[2]);
+ cur0 = GETJSAMPLE(range_limit[cur0]);
+ cur1 = GETJSAMPLE(range_limit[cur1]);
+ cur2 = GETJSAMPLE(range_limit[cur2]);
+ /* Index into the cache with adjusted pixel value */
+ cachep = & histogram[cur0>>C0_SHIFT][cur1>>C1_SHIFT][cur2>>C2_SHIFT];
+ /* If we have not seen this color before, find nearest colormap */
+ /* entry and update the cache */
+ if (*cachep == 0)
+ fill_inverse_cmap(cinfo, cur0>>C0_SHIFT,cur1>>C1_SHIFT,cur2>>C2_SHIFT);
+ /* Now emit the colormap index for this cell */
+ { register int pixcode = *cachep - 1;
+ *outptr = (JSAMPLE) pixcode;
+ /* Compute representation error for this pixel */
+ cur0 -= GETJSAMPLE(colormap0[pixcode]);
+ cur1 -= GETJSAMPLE(colormap1[pixcode]);
+ cur2 -= GETJSAMPLE(colormap2[pixcode]);
+ }
+ /* Compute error fractions to be propagated to adjacent pixels.
+ * Add these into the running sums, and simultaneously shift the
+ * next-line error sums left by 1 column.
+ */
+ { register LOCFSERROR bnexterr, delta;
+
+ bnexterr = cur0; /* Process component 0 */
+ delta = cur0 * 2;
+ cur0 += delta; /* form error * 3 */
+ errorptr[0] = (FSERROR) (bpreverr0 + cur0);
+ cur0 += delta; /* form error * 5 */
+ bpreverr0 = belowerr0 + cur0;
+ belowerr0 = bnexterr;
+ cur0 += delta; /* form error * 7 */
+ bnexterr = cur1; /* Process component 1 */
+ delta = cur1 * 2;
+ cur1 += delta; /* form error * 3 */
+ errorptr[1] = (FSERROR) (bpreverr1 + cur1);
+ cur1 += delta; /* form error * 5 */
+ bpreverr1 = belowerr1 + cur1;
+ belowerr1 = bnexterr;
+ cur1 += delta; /* form error * 7 */
+ bnexterr = cur2; /* Process component 2 */
+ delta = cur2 * 2;
+ cur2 += delta; /* form error * 3 */
+ errorptr[2] = (FSERROR) (bpreverr2 + cur2);
+ cur2 += delta; /* form error * 5 */
+ bpreverr2 = belowerr2 + cur2;
+ belowerr2 = bnexterr;
+ cur2 += delta; /* form error * 7 */
+ }
+ /* At this point curN contains the 7/16 error value to be propagated
+ * to the next pixel on the current line, and all the errors for the
+ * next line have been shifted over. We are therefore ready to move on.
+ */
+ inptr += dir3; /* Advance pixel pointers to next column */
+ outptr += dir;
+ errorptr += dir3; /* advance errorptr to current column */
+ }
+ /* Post-loop cleanup: we must unload the final error values into the
+ * final fserrors[] entry. Note we need not unload belowerrN because
+ * it is for the dummy column before or after the actual array.
+ */
+ errorptr[0] = (FSERROR) bpreverr0; /* unload prev errs into array */
+ errorptr[1] = (FSERROR) bpreverr1;
+ errorptr[2] = (FSERROR) bpreverr2;
+ }
+}
+
+
+/*
+ * Initialize the error-limiting transfer function (lookup table).
+ * The raw F-S error computation can potentially compute error values of up to
+ * +- MAXJSAMPLE. But we want the maximum correction applied to a pixel to be
+ * much less, otherwise obviously wrong pixels will be created. (Typical
+ * effects include weird fringes at color-area boundaries, isolated bright
+ * pixels in a dark area, etc.) The standard advice for avoiding this problem
+ * is to ensure that the "corners" of the color cube are allocated as output
+ * colors; then repeated errors in the same direction cannot cause cascading
+ * error buildup. However, that only prevents the error from getting
+ * completely out of hand; Aaron Giles reports that error limiting improves
+ * the results even with corner colors allocated.
+ * A simple clamping of the error values to about +- MAXJSAMPLE/8 works pretty
+ * well, but the smoother transfer function used below is even better. Thanks
+ * to Aaron Giles for this idea.
+ */
+
+LOCAL(void)
+init_error_limit (j_decompress_ptr cinfo)
+/* Allocate and fill in the error_limiter table */
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ int * table;
+ int in, out;
+
+ table = (int *) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, (MAXJSAMPLE*2+1) * SIZEOF(int));
+ table += MAXJSAMPLE; /* so can index -MAXJSAMPLE .. +MAXJSAMPLE */
+ cquantize->error_limiter = table;
+
+#define STEPSIZE ((MAXJSAMPLE+1)/16)
+ /* Map errors 1:1 up to +- MAXJSAMPLE/16 */
+ out = 0;
+ for (in = 0; in < STEPSIZE; in++, out++) {
+ table[in] = out; table[-in] = -out;
+ }
+ /* Map errors 1:2 up to +- 3*MAXJSAMPLE/16 */
+ for (; in < STEPSIZE*3; in++, out += (in&1) ? 0 : 1) {
+ table[in] = out; table[-in] = -out;
+ }
+ /* Clamp the rest to final out value (which is (MAXJSAMPLE+1)/8) */
+ for (; in <= MAXJSAMPLE; in++) {
+ table[in] = out; table[-in] = -out;
+ }
+#undef STEPSIZE
+}
+
+
+/*
+ * Finish up at the end of each pass.
+ */
+
+METHODDEF(void)
+finish_pass1 (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+
+ /* Select the representative colors and fill in cinfo->colormap */
+ cinfo->colormap = cquantize->sv_colormap;
+ select_colors(cinfo, cquantize->desired);
+ /* Force next pass to zero the color index table */
+ cquantize->needs_zeroed = TRUE;
+}
+
+
+METHODDEF(void)
+finish_pass2 (j_decompress_ptr cinfo)
+{
+ (void)cinfo;
+ /* no work */
+}
+
+
+/*
+ * Initialize for each processing pass.
+ */
+
+METHODDEF(void)
+start_pass_2_quant (j_decompress_ptr cinfo, boolean is_pre_scan)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+ hist3d histogram = cquantize->histogram;
+ int i;
+
+ /* Only F-S dithering or no dithering is supported. */
+ /* If user asks for ordered dither, give him F-S. */
+ if (cinfo->dither_mode != JDITHER_NONE)
+ cinfo->dither_mode = JDITHER_FS;
+
+ if (is_pre_scan) {
+ /* Set up method pointers */
+ cquantize->pub.color_quantize = prescan_quantize;
+ cquantize->pub.finish_pass = finish_pass1;
+ cquantize->needs_zeroed = TRUE; /* Always zero histogram */
+ } else {
+ /* Set up method pointers */
+ if (cinfo->dither_mode == JDITHER_FS)
+ cquantize->pub.color_quantize = pass2_fs_dither;
+ else
+ cquantize->pub.color_quantize = pass2_no_dither;
+ cquantize->pub.finish_pass = finish_pass2;
+
+ /* Make sure color count is acceptable */
+ i = cinfo->actual_number_of_colors;
+ if (i < 1)
+ ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, 1);
+ if (i > MAXNUMCOLORS)
+ ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXNUMCOLORS);
+
+ if (cinfo->dither_mode == JDITHER_FS) {
+ size_t arraysize = (size_t) ((cinfo->output_width + 2) *
+ (3 * SIZEOF(FSERROR)));
+ /* Allocate Floyd-Steinberg workspace if we didn't already. */
+ if (cquantize->fserrors == NULL)
+ cquantize->fserrors = (FSERRPTR) (*cinfo->mem->alloc_large)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);
+ /* Initialize the propagated errors to zero. */
+ jzero_far((void FAR *) cquantize->fserrors, arraysize);
+ /* Make the error-limit table if we didn't already. */
+ if (cquantize->error_limiter == NULL)
+ init_error_limit(cinfo);
+ cquantize->on_odd_row = FALSE;
+ }
+
+ }
+ /* Zero the histogram or inverse color map, if necessary */
+ if (cquantize->needs_zeroed) {
+ for (i = 0; i < HIST_C0_ELEMS; i++) {
+ jzero_far((void FAR *) histogram[i],
+ HIST_C1_ELEMS*HIST_C2_ELEMS * SIZEOF(histcell));
+ }
+ cquantize->needs_zeroed = FALSE;
+ }
+}
+
+
+/*
+ * Switch to a new external colormap between output passes.
+ */
+
+METHODDEF(void)
+new_color_map_2_quant (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
+
+ /* Reset the inverse color map */
+ cquantize->needs_zeroed = TRUE;
+}
+
+
+/*
+ * Module initialization routine for 2-pass color quantization.
+ */
+
+GLOBAL(void)
+jinit_2pass_quantizer (j_decompress_ptr cinfo)
+{
+ my_cquantize_ptr cquantize;
+ int i;
+
+ cquantize = (my_cquantize_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_cquantizer));
+ cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;
+ cquantize->pub.start_pass = start_pass_2_quant;
+ cquantize->pub.new_color_map = new_color_map_2_quant;
+ cquantize->fserrors = NULL; /* flag optional arrays not allocated */
+ cquantize->error_limiter = NULL;
+
+ /* Make sure jdmaster didn't give me a case I can't handle */
+ if (cinfo->out_color_components != 3)
+ ERREXIT(cinfo, JERR_NOTIMPL);
+
+ /* Allocate the histogram/inverse colormap storage */
+ cquantize->histogram = (hist3d) (*cinfo->mem->alloc_small)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE, HIST_C0_ELEMS * SIZEOF(hist2d));
+ for (i = 0; i < HIST_C0_ELEMS; i++) {
+ cquantize->histogram[i] = (hist2d) (*cinfo->mem->alloc_large)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ HIST_C1_ELEMS*HIST_C2_ELEMS * SIZEOF(histcell));
+ }
+ cquantize->needs_zeroed = TRUE; /* histogram is garbage now */
+
+ /* Allocate storage for the completed colormap, if required.
+ * We do this now since it is FAR storage and may affect
+ * the memory manager's space calculations.
+ */
+ if (cinfo->enable_2pass_quant) {
+ /* Make sure color count is acceptable */
+ int desired = cinfo->desired_number_of_colors;
+ /* Lower bound on # of colors ... somewhat arbitrary as long as > 0 */
+ if (desired < 8)
+ ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, 8);
+ /* Make sure colormap indexes can be represented by JSAMPLEs */
+ if (desired > MAXNUMCOLORS)
+ ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXNUMCOLORS);
+ cquantize->sv_colormap = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo,JPOOL_IMAGE, (JDIMENSION) desired, (JDIMENSION) 3);
+ cquantize->desired = desired;
+ } else
+ cquantize->sv_colormap = NULL;
+
+ /* Only F-S dithering or no dithering is supported. */
+ /* If user asks for ordered dither, give him F-S. */
+ if (cinfo->dither_mode != JDITHER_NONE)
+ cinfo->dither_mode = JDITHER_FS;
+
+ /* Allocate Floyd-Steinberg workspace if necessary.
+ * This isn't really needed until pass 2, but again it is FAR storage.
+ * Although we will cope with a later change in dither_mode,
+ * we do not promise to honor max_memory_to_use if dither_mode changes.
+ */
+ if (cinfo->dither_mode == JDITHER_FS) {
+ cquantize->fserrors = (FSERRPTR) (*cinfo->mem->alloc_large)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (size_t) ((cinfo->output_width + 2) * (3 * SIZEOF(FSERROR))));
+ /* Might as well create the error-limiting table too. */
+ init_error_limit(cinfo);
+ }
+}
+
+#endif /* QUANT_2PASS_SUPPORTED */
--- /dev/null
+/*
+ * jutils.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains tables and miscellaneous utility routines needed
+ * for both compression and decompression.
+ * Note we prefix all global names with "j" to minimize conflicts with
+ * a surrounding application.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * jpeg_zigzag_order[i] is the zigzag-order position of the i'th element
+ * of a DCT block read in natural order (left to right, top to bottom).
+ */
+
+#if 0 /* This table is not actually needed in v6a */
+
+const int jpeg_zigzag_order[DCTSIZE2] = {
+ 0, 1, 5, 6, 14, 15, 27, 28,
+ 2, 4, 7, 13, 16, 26, 29, 42,
+ 3, 8, 12, 17, 25, 30, 41, 43,
+ 9, 11, 18, 24, 31, 40, 44, 53,
+ 10, 19, 23, 32, 39, 45, 52, 54,
+ 20, 22, 33, 38, 46, 51, 55, 60,
+ 21, 34, 37, 47, 50, 56, 59, 61,
+ 35, 36, 48, 49, 57, 58, 62, 63
+};
+
+#endif
+
+/*
+ * jpeg_natural_order[i] is the natural-order position of the i'th element
+ * of zigzag order.
+ *
+ * When reading corrupted data, the Huffman decoders could attempt
+ * to reference an entry beyond the end of this array (if the decoded
+ * zero run length reaches past the end of the block). To prevent
+ * wild stores without adding an inner-loop test, we put some extra
+ * "63"s after the real entries. This will cause the extra coefficient
+ * to be stored in location 63 of the block, not somewhere random.
+ * The worst case would be a run-length of 15, which means we need 16
+ * fake entries.
+ */
+
+const int jpeg_natural_order[DCTSIZE2+16] = {
+ 0, 1, 8, 16, 9, 2, 3, 10,
+ 17, 24, 32, 25, 18, 11, 4, 5,
+ 12, 19, 26, 33, 40, 48, 41, 34,
+ 27, 20, 13, 6, 7, 14, 21, 28,
+ 35, 42, 49, 56, 57, 50, 43, 36,
+ 29, 22, 15, 23, 30, 37, 44, 51,
+ 58, 59, 52, 45, 38, 31, 39, 46,
+ 53, 60, 61, 54, 47, 55, 62, 63,
+ 63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
+ 63, 63, 63, 63, 63, 63, 63, 63
+};
+
+
+/*
+ * Arithmetic utilities
+ */
+
+GLOBAL(long)
+jdiv_round_up (long a, long b)
+/* Compute a/b rounded up to next integer, ie, ceil(a/b) */
+/* Assumes a >= 0, b > 0 */
+{
+ return (a + b - 1L) / b;
+}
+
+
+GLOBAL(long)
+jround_up (long a, long b)
+/* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
+/* Assumes a >= 0, b > 0 */
+{
+ a += b - 1L;
+ return a - (a % b);
+}
+
+
+/* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
+ * and coefficient-block arrays. This won't work on 80x86 because the arrays
+ * are FAR and we're assuming a small-pointer memory model. However, some
+ * DOS compilers provide far-pointer versions of memcpy() and memset() even
+ * in the small-model libraries. These will be used if USE_FMEM is defined.
+ * Otherwise, the routines below do it the hard way. (The performance cost
+ * is not all that great, because these routines aren't very heavily used.)
+ */
+
+#ifndef NEED_FAR_POINTERS /* normal case, same as regular macros */
+#define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size)
+#define FMEMZERO(target,size) MEMZERO(target,size)
+#else /* 80x86 case, define if we can */
+#ifdef USE_FMEM
+#define FMEMCOPY(dest,src,size) _fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
+#define FMEMZERO(target,size) _fmemset((void FAR *)(target), 0, (size_t)(size))
+#endif
+#endif
+
+
+GLOBAL(void)
+jcopy_sample_rows (JSAMPARRAY input_array, int source_row,
+ JSAMPARRAY output_array, int dest_row,
+ int num_rows, JDIMENSION num_cols)
+/* Copy some rows of samples from one place to another.
+ * num_rows rows are copied from input_array[source_row++]
+ * to output_array[dest_row++]; these areas may overlap for duplication.
+ * The source and destination arrays must be at least as wide as num_cols.
+ */
+{
+ register JSAMPROW inptr, outptr;
+#ifdef FMEMCOPY
+ register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
+#else
+ register JDIMENSION count;
+#endif
+ register int row;
+
+ input_array += source_row;
+ output_array += dest_row;
+
+ for (row = num_rows; row > 0; row--) {
+ inptr = *input_array++;
+ outptr = *output_array++;
+#ifdef FMEMCOPY
+ FMEMCOPY(outptr, inptr, count);
+#else
+ for (count = num_cols; count > 0; count--)
+ *outptr++ = *inptr++; /* needn't bother with GETJSAMPLE() here */
+#endif
+ }
+}
+
+
+GLOBAL(void)
+jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row,
+ JDIMENSION num_blocks)
+/* Copy a row of coefficient blocks from one place to another. */
+{
+#ifdef FMEMCOPY
+ FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
+#else
+ register JCOEFPTR inptr, outptr;
+ register long count;
+
+ inptr = (JCOEFPTR) input_row;
+ outptr = (JCOEFPTR) output_row;
+ for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
+ *outptr++ = *inptr++;
+ }
+#endif
+}
+
+
+GLOBAL(void)
+jzero_far (void FAR * target, size_t bytestozero)
+/* Zero out a chunk of FAR memory. */
+/* This might be sample-array data, block-array data, or alloc_large data. */
+{
+#ifdef FMEMZERO
+ FMEMZERO(target, bytestozero);
+#else
+ register char FAR * ptr = (char FAR *) target;
+ register size_t count;
+
+ for (count = bytestozero; count > 0; count--) {
+ *ptr++ = 0;
+ }
+#endif
+}
--- /dev/null
+/*
+ * jversion.h
+ *
+ * Copyright (C) 1991-1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains software version identification.
+ */
+
+
+#define JVERSION "6b 27-Mar-1998"
+
+#define JCOPYRIGHT "Copyright (C) 1998, Thomas G. Lane"
--- /dev/null
+USING THE IJG JPEG LIBRARY
+
+Copyright (C) 1994-1998, Thomas G. Lane.
+This file is part of the Independent JPEG Group's software.
+For conditions of distribution and use, see the accompanying README file.
+
+
+This file describes how to use the IJG JPEG library within an application
+program. Read it if you want to write a program that uses the library.
+
+The file example.c provides heavily commented skeleton code for calling the
+JPEG library. Also see jpeglib.h (the include file to be used by application
+programs) for full details about data structures and function parameter lists.
+The library source code, of course, is the ultimate reference.
+
+Note that there have been *major* changes from the application interface
+presented by IJG version 4 and earlier versions. The old design had several
+inherent limitations, and it had accumulated a lot of cruft as we added
+features while trying to minimize application-interface changes. We have
+sacrificed backward compatibility in the version 5 rewrite, but we think the
+improvements justify this.
+
+
+TABLE OF CONTENTS
+-----------------
+
+Overview:
+ Functions provided by the library
+ Outline of typical usage
+Basic library usage:
+ Data formats
+ Compression details
+ Decompression details
+ Mechanics of usage: include files, linking, etc
+Advanced features:
+ Compression parameter selection
+ Decompression parameter selection
+ Special color spaces
+ Error handling
+ Compressed data handling (source and destination managers)
+ I/O suspension
+ Progressive JPEG support
+ Buffered-image mode
+ Abbreviated datastreams and multiple images
+ Special markers
+ Raw (downsampled) image data
+ Really raw data: DCT coefficients
+ Progress monitoring
+ Memory management
+ Memory usage
+ Library compile-time options
+ Portability considerations
+ Notes for MS-DOS implementors
+
+You should read at least the overview and basic usage sections before trying
+to program with the library. The sections on advanced features can be read
+if and when you need them.
+
+
+OVERVIEW
+========
+
+Functions provided by the library
+---------------------------------
+
+The IJG JPEG library provides C code to read and write JPEG-compressed image
+files. The surrounding application program receives or supplies image data a
+scanline at a time, using a straightforward uncompressed image format. All
+details of color conversion and other preprocessing/postprocessing can be
+handled by the library.
+
+The library includes a substantial amount of code that is not covered by the
+JPEG standard but is necessary for typical applications of JPEG. These
+functions preprocess the image before JPEG compression or postprocess it after
+decompression. They include colorspace conversion, downsampling/upsampling,
+and color quantization. The application indirectly selects use of this code
+by specifying the format in which it wishes to supply or receive image data.
+For example, if colormapped output is requested, then the decompression
+library automatically invokes color quantization.
+
+A wide range of quality vs. speed tradeoffs are possible in JPEG processing,
+and even more so in decompression postprocessing. The decompression library
+provides multiple implementations that cover most of the useful tradeoffs,
+ranging from very-high-quality down to fast-preview operation. On the
+compression side we have generally not provided low-quality choices, since
+compression is normally less time-critical. It should be understood that the
+low-quality modes may not meet the JPEG standard's accuracy requirements;
+nonetheless, they are useful for viewers.
+
+A word about functions *not* provided by the library. We handle a subset of
+the ISO JPEG standard; most baseline, extended-sequential, and progressive
+JPEG processes are supported. (Our subset includes all features now in common
+use.) Unsupported ISO options include:
+ * Hierarchical storage
+ * Arithmetic entropy coding (unsupported for legal reasons)
+ * DNL marker
+ * Nonintegral subsampling ratios
+We support both 8- and 12-bit data precision, but this is a compile-time
+choice rather than a run-time choice; hence it is difficult to use both
+precisions in a single application.
+
+By itself, the library handles only interchange JPEG datastreams --- in
+particular the widely used JFIF file format. The library can be used by
+surrounding code to process interchange or abbreviated JPEG datastreams that
+are embedded in more complex file formats. (For example, this library is
+used by the free LIBTIFF library to support JPEG compression in TIFF.)
+
+
+Outline of typical usage
+------------------------
+
+The rough outline of a JPEG compression operation is:
+
+ Allocate and initialize a JPEG compression object
+ Specify the destination for the compressed data (eg, a file)
+ Set parameters for compression, including image size & colorspace
+ jpeg_start_compress(...);
+ while (scan lines remain to be written)
+ jpeg_write_scanlines(...);
+ jpeg_finish_compress(...);
+ Release the JPEG compression object
+
+A JPEG compression object holds parameters and working state for the JPEG
+library. We make creation/destruction of the object separate from starting
+or finishing compression of an image; the same object can be re-used for a
+series of image compression operations. This makes it easy to re-use the
+same parameter settings for a sequence of images. Re-use of a JPEG object
+also has important implications for processing abbreviated JPEG datastreams,
+as discussed later.
+
+The image data to be compressed is supplied to jpeg_write_scanlines() from
+in-memory buffers. If the application is doing file-to-file compression,
+reading image data from the source file is the application's responsibility.
+The library emits compressed data by calling a "data destination manager",
+which typically will write the data into a file; but the application can
+provide its own destination manager to do something else.
+
+Similarly, the rough outline of a JPEG decompression operation is:
+
+ Allocate and initialize a JPEG decompression object
+ Specify the source of the compressed data (eg, a file)
+ Call jpeg_read_header() to obtain image info
+ Set parameters for decompression
+ jpeg_start_decompress(...);
+ while (scan lines remain to be read)
+ jpeg_read_scanlines(...);
+ jpeg_finish_decompress(...);
+ Release the JPEG decompression object
+
+This is comparable to the compression outline except that reading the
+datastream header is a separate step. This is helpful because information
+about the image's size, colorspace, etc is available when the application
+selects decompression parameters. For example, the application can choose an
+output scaling ratio that will fit the image into the available screen size.
+
+The decompression library obtains compressed data by calling a data source
+manager, which typically will read the data from a file; but other behaviors
+can be obtained with a custom source manager. Decompressed data is delivered
+into in-memory buffers passed to jpeg_read_scanlines().
+
+It is possible to abort an incomplete compression or decompression operation
+by calling jpeg_abort(); or, if you do not need to retain the JPEG object,
+simply release it by calling jpeg_destroy().
+
+JPEG compression and decompression objects are two separate struct types.
+However, they share some common fields, and certain routines such as
+jpeg_destroy() can work on either type of object.
+
+The JPEG library has no static variables: all state is in the compression
+or decompression object. Therefore it is possible to process multiple
+compression and decompression operations concurrently, using multiple JPEG
+objects.
+
+Both compression and decompression can be done in an incremental memory-to-
+memory fashion, if suitable source/destination managers are used. See the
+section on "I/O suspension" for more details.
+
+
+BASIC LIBRARY USAGE
+===================
+
+Data formats
+------------
+
+Before diving into procedural details, it is helpful to understand the
+image data format that the JPEG library expects or returns.
+
+The standard input image format is a rectangular array of pixels, with each
+pixel having the same number of "component" or "sample" values (color
+channels). You must specify how many components there are and the colorspace
+interpretation of the components. Most applications will use RGB data
+(three components per pixel) or grayscale data (one component per pixel).
+PLEASE NOTE THAT RGB DATA IS THREE SAMPLES PER PIXEL, GRAYSCALE ONLY ONE.
+A remarkable number of people manage to miss this, only to find that their
+programs don't work with grayscale JPEG files.
+
+There is no provision for colormapped input. JPEG files are always full-color
+or full grayscale (or sometimes another colorspace such as CMYK). You can
+feed in a colormapped image by expanding it to full-color format. However
+JPEG often doesn't work very well with source data that has been colormapped,
+because of dithering noise. This is discussed in more detail in the JPEG FAQ
+and the other references mentioned in the README file.
+
+Pixels are stored by scanlines, with each scanline running from left to
+right. The component values for each pixel are adjacent in the row; for
+example, R,G,B,R,G,B,R,G,B,... for 24-bit RGB color. Each scanline is an
+array of data type JSAMPLE --- which is typically "unsigned char", unless
+you've changed jmorecfg.h. (You can also change the RGB pixel layout, say
+to B,G,R order, by modifying jmorecfg.h. But see the restrictions listed in
+that file before doing so.)
+
+A 2-D array of pixels is formed by making a list of pointers to the starts of
+scanlines; so the scanlines need not be physically adjacent in memory. Even
+if you process just one scanline at a time, you must make a one-element
+pointer array to conform to this structure. Pointers to JSAMPLE rows are of
+type JSAMPROW, and the pointer to the pointer array is of type JSAMPARRAY.
+
+The library accepts or supplies one or more complete scanlines per call.
+It is not possible to process part of a row at a time. Scanlines are always
+processed top-to-bottom. You can process an entire image in one call if you
+have it all in memory, but usually it's simplest to process one scanline at
+a time.
+
+For best results, source data values should have the precision specified by
+BITS_IN_JSAMPLE (normally 8 bits). For instance, if you choose to compress
+data that's only 6 bits/channel, you should left-justify each value in a
+byte before passing it to the compressor. If you need to compress data
+that has more than 8 bits/channel, compile with BITS_IN_JSAMPLE = 12.
+(See "Library compile-time options", later.)
+
+
+The data format returned by the decompressor is the same in all details,
+except that colormapped output is supported. (Again, a JPEG file is never
+colormapped. But you can ask the decompressor to perform on-the-fly color
+quantization to deliver colormapped output.) If you request colormapped
+output then the returned data array contains a single JSAMPLE per pixel;
+its value is an index into a color map. The color map is represented as
+a 2-D JSAMPARRAY in which each row holds the values of one color component,
+that is, colormap[i][j] is the value of the i'th color component for pixel
+value (map index) j. Note that since the colormap indexes are stored in
+JSAMPLEs, the maximum number of colors is limited by the size of JSAMPLE
+(ie, at most 256 colors for an 8-bit JPEG library).
+
+
+Compression details
+-------------------
+
+Here we revisit the JPEG compression outline given in the overview.
+
+1. Allocate and initialize a JPEG compression object.
+
+A JPEG compression object is a "struct jpeg_compress_struct". (It also has
+a bunch of subsidiary structures which are allocated via malloc(), but the
+application doesn't control those directly.) This struct can be just a local
+variable in the calling routine, if a single routine is going to execute the
+whole JPEG compression sequence. Otherwise it can be static or allocated
+from malloc().
+
+You will also need a structure representing a JPEG error handler. The part
+of this that the library cares about is a "struct jpeg_error_mgr". If you
+are providing your own error handler, you'll typically want to embed the
+jpeg_error_mgr struct in a larger structure; this is discussed later under
+"Error handling". For now we'll assume you are just using the default error
+handler. The default error handler will print JPEG error/warning messages
+on stderr, and it will call exit() if a fatal error occurs.
+
+You must initialize the error handler structure, store a pointer to it into
+the JPEG object's "err" field, and then call jpeg_create_compress() to
+initialize the rest of the JPEG object.
+
+Typical code for this step, if you are using the default error handler, is
+
+ struct jpeg_compress_struct cinfo;
+ struct jpeg_error_mgr jerr;
+ ...
+ cinfo.err = jpeg_std_error(&jerr);
+ jpeg_create_compress(&cinfo);
+
+jpeg_create_compress allocates a small amount of memory, so it could fail
+if you are out of memory. In that case it will exit via the error handler;
+that's why the error handler must be initialized first.
+
+
+2. Specify the destination for the compressed data (eg, a file).
+
+As previously mentioned, the JPEG library delivers compressed data to a
+"data destination" module. The library includes one data destination
+module which knows how to write to a stdio stream. You can use your own
+destination module if you want to do something else, as discussed later.
+
+If you use the standard destination module, you must open the target stdio
+stream beforehand. Typical code for this step looks like:
+
+ FILE * outfile;
+ ...
+ if ((outfile = fopen(filename, "wb")) == NULL) {
+ fprintf(stderr, "can't open %s\n", filename);
+ exit(1);
+ }
+ jpeg_stdio_dest(&cinfo, outfile);
+
+where the last line invokes the standard destination module.
+
+WARNING: it is critical that the binary compressed data be delivered to the
+output file unchanged. On non-Unix systems the stdio library may perform
+newline translation or otherwise corrupt binary data. To suppress this
+behavior, you may need to use a "b" option to fopen (as shown above), or use
+setmode() or another routine to put the stdio stream in binary mode. See
+cjpeg.c and djpeg.c for code that has been found to work on many systems.
+
+You can select the data destination after setting other parameters (step 3),
+if that's more convenient. You may not change the destination between
+calling jpeg_start_compress() and jpeg_finish_compress().
+
+
+3. Set parameters for compression, including image size & colorspace.
+
+You must supply information about the source image by setting the following
+fields in the JPEG object (cinfo structure):
+
+ image_width Width of image, in pixels
+ image_height Height of image, in pixels
+ input_components Number of color channels (samples per pixel)
+ in_color_space Color space of source image
+
+The image dimensions are, hopefully, obvious. JPEG supports image dimensions
+of 1 to 64K pixels in either direction. The input color space is typically
+RGB or grayscale, and input_components is 3 or 1 accordingly. (See "Special
+color spaces", later, for more info.) The in_color_space field must be
+assigned one of the J_COLOR_SPACE enum constants, typically JCS_RGB or
+JCS_GRAYSCALE.
+
+JPEG has a large number of compression parameters that determine how the
+image is encoded. Most applications don't need or want to know about all
+these parameters. You can set all the parameters to reasonable defaults by
+calling jpeg_set_defaults(); then, if there are particular values you want
+to change, you can do so after that. The "Compression parameter selection"
+section tells about all the parameters.
+
+You must set in_color_space correctly before calling jpeg_set_defaults(),
+because the defaults depend on the source image colorspace. However the
+other three source image parameters need not be valid until you call
+jpeg_start_compress(). There's no harm in calling jpeg_set_defaults() more
+than once, if that happens to be convenient.
+
+Typical code for a 24-bit RGB source image is
+
+ cinfo.image_width = Width; /* image width and height, in pixels */
+ cinfo.image_height = Height;
+ cinfo.input_components = 3; /* # of color components per pixel */
+ cinfo.in_color_space = JCS_RGB; /* colorspace of input image */
+
+ jpeg_set_defaults(&cinfo);
+ /* Make optional parameter settings here */
+
+
+4. jpeg_start_compress(...);
+
+After you have established the data destination and set all the necessary
+source image info and other parameters, call jpeg_start_compress() to begin
+a compression cycle. This will initialize internal state, allocate working
+storage, and emit the first few bytes of the JPEG datastream header.
+
+Typical code:
+
+ jpeg_start_compress(&cinfo, TRUE);
+
+The "TRUE" parameter ensures that a complete JPEG interchange datastream
+will be written. This is appropriate in most cases. If you think you might
+want to use an abbreviated datastream, read the section on abbreviated
+datastreams, below.
+
+Once you have called jpeg_start_compress(), you may not alter any JPEG
+parameters or other fields of the JPEG object until you have completed
+the compression cycle.
+
+
+5. while (scan lines remain to be written)
+ jpeg_write_scanlines(...);
+
+Now write all the required image data by calling jpeg_write_scanlines()
+one or more times. You can pass one or more scanlines in each call, up
+to the total image height. In most applications it is convenient to pass
+just one or a few scanlines at a time. The expected format for the passed
+data is discussed under "Data formats", above.
+
+Image data should be written in top-to-bottom scanline order. The JPEG spec
+contains some weasel wording about how top and bottom are application-defined
+terms (a curious interpretation of the English language...) but if you want
+your files to be compatible with everyone else's, you WILL use top-to-bottom
+order. If the source data must be read in bottom-to-top order, you can use
+the JPEG library's virtual array mechanism to invert the data efficiently.
+Examples of this can be found in the sample application cjpeg.
+
+The library maintains a count of the number of scanlines written so far
+in the next_scanline field of the JPEG object. Usually you can just use
+this variable as the loop counter, so that the loop test looks like
+"while (cinfo.next_scanline < cinfo.image_height)".
+
+Code for this step depends heavily on the way that you store the source data.
+example.c shows the following code for the case of a full-size 2-D source
+array containing 3-byte RGB pixels:
+
+ JSAMPROW row_pointer[1]; /* pointer to a single row */
+ int row_stride; /* physical row width in buffer */
+
+ row_stride = image_width * 3; /* JSAMPLEs per row in image_buffer */
+
+ while (cinfo.next_scanline < cinfo.image_height) {
+ row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride];
+ jpeg_write_scanlines(&cinfo, row_pointer, 1);
+ }
+
+jpeg_write_scanlines() returns the number of scanlines actually written.
+This will normally be equal to the number passed in, so you can usually
+ignore the return value. It is different in just two cases:
+ * If you try to write more scanlines than the declared image height,
+ the additional scanlines are ignored.
+ * If you use a suspending data destination manager, output buffer overrun
+ will cause the compressor to return before accepting all the passed lines.
+ This feature is discussed under "I/O suspension", below. The normal
+ stdio destination manager will NOT cause this to happen.
+In any case, the return value is the same as the change in the value of
+next_scanline.
+
+
+6. jpeg_finish_compress(...);
+
+After all the image data has been written, call jpeg_finish_compress() to
+complete the compression cycle. This step is ESSENTIAL to ensure that the
+last bufferload of data is written to the data destination.
+jpeg_finish_compress() also releases working memory associated with the JPEG
+object.
+
+Typical code:
+
+ jpeg_finish_compress(&cinfo);
+
+If using the stdio destination manager, don't forget to close the output
+stdio stream (if necessary) afterwards.
+
+If you have requested a multi-pass operating mode, such as Huffman code
+optimization, jpeg_finish_compress() will perform the additional passes using
+data buffered by the first pass. In this case jpeg_finish_compress() may take
+quite a while to complete. With the default compression parameters, this will
+not happen.
+
+It is an error to call jpeg_finish_compress() before writing the necessary
+total number of scanlines. If you wish to abort compression, call
+jpeg_abort() as discussed below.
+
+After completing a compression cycle, you may dispose of the JPEG object
+as discussed next, or you may use it to compress another image. In that case
+return to step 2, 3, or 4 as appropriate. If you do not change the
+destination manager, the new datastream will be written to the same target.
+If you do not change any JPEG parameters, the new datastream will be written
+with the same parameters as before. Note that you can change the input image
+dimensions freely between cycles, but if you change the input colorspace, you
+should call jpeg_set_defaults() to adjust for the new colorspace; and then
+you'll need to repeat all of step 3.
+
+
+7. Release the JPEG compression object.
+
+When you are done with a JPEG compression object, destroy it by calling
+jpeg_destroy_compress(). This will free all subsidiary memory (regardless of
+the previous state of the object). Or you can call jpeg_destroy(), which
+works for either compression or decompression objects --- this may be more
+convenient if you are sharing code between compression and decompression
+cases. (Actually, these routines are equivalent except for the declared type
+of the passed pointer. To avoid gripes from ANSI C compilers, jpeg_destroy()
+should be passed a j_common_ptr.)
+
+If you allocated the jpeg_compress_struct structure from malloc(), freeing
+it is your responsibility --- jpeg_destroy() won't. Ditto for the error
+handler structure.
+
+Typical code:
+
+ jpeg_destroy_compress(&cinfo);
+
+
+8. Aborting.
+
+If you decide to abort a compression cycle before finishing, you can clean up
+in either of two ways:
+
+* If you don't need the JPEG object any more, just call
+ jpeg_destroy_compress() or jpeg_destroy() to release memory. This is
+ legitimate at any point after calling jpeg_create_compress() --- in fact,
+ it's safe even if jpeg_create_compress() fails.
+
+* If you want to re-use the JPEG object, call jpeg_abort_compress(), or call
+ jpeg_abort() which works on both compression and decompression objects.
+ This will return the object to an idle state, releasing any working memory.
+ jpeg_abort() is allowed at any time after successful object creation.
+
+Note that cleaning up the data destination, if required, is your
+responsibility; neither of these routines will call term_destination().
+(See "Compressed data handling", below, for more about that.)
+
+jpeg_destroy() and jpeg_abort() are the only safe calls to make on a JPEG
+object that has reported an error by calling error_exit (see "Error handling"
+for more info). The internal state of such an object is likely to be out of
+whack. Either of these two routines will return the object to a known state.
+
+
+Decompression details
+---------------------
+
+Here we revisit the JPEG decompression outline given in the overview.
+
+1. Allocate and initialize a JPEG decompression object.
+
+This is just like initialization for compression, as discussed above,
+except that the object is a "struct jpeg_decompress_struct" and you
+call jpeg_create_decompress(). Error handling is exactly the same.
+
+Typical code:
+
+ struct jpeg_decompress_struct cinfo;
+ struct jpeg_error_mgr jerr;
+ ...
+ cinfo.err = jpeg_std_error(&jerr);
+ jpeg_create_decompress(&cinfo);
+
+(Both here and in the IJG code, we usually use variable name "cinfo" for
+both compression and decompression objects.)
+
+
+2. Specify the source of the compressed data (eg, a file).
+
+As previously mentioned, the JPEG library reads compressed data from a "data
+source" module. The library includes one data source module which knows how
+to read from a stdio stream. You can use your own source module if you want
+to do something else, as discussed later.
+
+If you use the standard source module, you must open the source stdio stream
+beforehand. Typical code for this step looks like:
+
+ FILE * infile;
+ ...
+ if ((infile = fopen(filename, "rb")) == NULL) {
+ fprintf(stderr, "can't open %s\n", filename);
+ exit(1);
+ }
+ jpeg_stdio_src(&cinfo, infile);
+
+where the last line invokes the standard source module.
+
+WARNING: it is critical that the binary compressed data be read unchanged.
+On non-Unix systems the stdio library may perform newline translation or
+otherwise corrupt binary data. To suppress this behavior, you may need to use
+a "b" option to fopen (as shown above), or use setmode() or another routine to
+put the stdio stream in binary mode. See cjpeg.c and djpeg.c for code that
+has been found to work on many systems.
+
+You may not change the data source between calling jpeg_read_header() and
+jpeg_finish_decompress(). If you wish to read a series of JPEG images from
+a single source file, you should repeat the jpeg_read_header() to
+jpeg_finish_decompress() sequence without reinitializing either the JPEG
+object or the data source module; this prevents buffered input data from
+being discarded.
+
+
+3. Call jpeg_read_header() to obtain image info.
+
+Typical code for this step is just
+
+ jpeg_read_header(&cinfo, TRUE);
+
+This will read the source datastream header markers, up to the beginning
+of the compressed data proper. On return, the image dimensions and other
+info have been stored in the JPEG object. The application may wish to
+consult this information before selecting decompression parameters.
+
+More complex code is necessary if
+ * A suspending data source is used --- in that case jpeg_read_header()
+ may return before it has read all the header data. See "I/O suspension",
+ below. The normal stdio source manager will NOT cause this to happen.
+ * Abbreviated JPEG files are to be processed --- see the section on
+ abbreviated datastreams. Standard applications that deal only in
+ interchange JPEG files need not be concerned with this case either.
+
+It is permissible to stop at this point if you just wanted to find out the
+image dimensions and other header info for a JPEG file. In that case,
+call jpeg_destroy() when you are done with the JPEG object, or call
+jpeg_abort() to return it to an idle state before selecting a new data
+source and reading another header.
+
+
+4. Set parameters for decompression.
+
+jpeg_read_header() sets appropriate default decompression parameters based on
+the properties of the image (in particular, its colorspace). However, you
+may well want to alter these defaults before beginning the decompression.
+For example, the default is to produce full color output from a color file.
+If you want colormapped output you must ask for it. Other options allow the
+returned image to be scaled and allow various speed/quality tradeoffs to be
+selected. "Decompression parameter selection", below, gives details.
+
+If the defaults are appropriate, nothing need be done at this step.
+
+Note that all default values are set by each call to jpeg_read_header().
+If you reuse a decompression object, you cannot expect your parameter
+settings to be preserved across cycles, as you can for compression.
+You must set desired parameter values each time.
+
+
+5. jpeg_start_decompress(...);
+
+Once the parameter values are satisfactory, call jpeg_start_decompress() to
+begin decompression. This will initialize internal state, allocate working
+memory, and prepare for returning data.
+
+Typical code is just
+
+ jpeg_start_decompress(&cinfo);
+
+If you have requested a multi-pass operating mode, such as 2-pass color
+quantization, jpeg_start_decompress() will do everything needed before data
+output can begin. In this case jpeg_start_decompress() may take quite a while
+to complete. With a single-scan (non progressive) JPEG file and default
+decompression parameters, this will not happen; jpeg_start_decompress() will
+return quickly.
+
+After this call, the final output image dimensions, including any requested
+scaling, are available in the JPEG object; so is the selected colormap, if
+colormapped output has been requested. Useful fields include
+
+ output_width image width and height, as scaled
+ output_height
+ out_color_components # of color components in out_color_space
+ output_components # of color components returned per pixel
+ colormap the selected colormap, if any
+ actual_number_of_colors number of entries in colormap
+
+output_components is 1 (a colormap index) when quantizing colors; otherwise it
+equals out_color_components. It is the number of JSAMPLE values that will be
+emitted per pixel in the output arrays.
+
+Typically you will need to allocate data buffers to hold the incoming image.
+You will need output_width * output_components JSAMPLEs per scanline in your
+output buffer, and a total of output_height scanlines will be returned.
+
+Note: if you are using the JPEG library's internal memory manager to allocate
+data buffers (as djpeg does), then the manager's protocol requires that you
+request large buffers *before* calling jpeg_start_decompress(). This is a
+little tricky since the output_XXX fields are not normally valid then. You
+can make them valid by calling jpeg_calc_output_dimensions() after setting the
+relevant parameters (scaling, output color space, and quantization flag).
+
+
+6. while (scan lines remain to be read)
+ jpeg_read_scanlines(...);
+
+Now you can read the decompressed image data by calling jpeg_read_scanlines()
+one or more times. At each call, you pass in the maximum number of scanlines
+to be read (ie, the height of your working buffer); jpeg_read_scanlines()
+will return up to that many lines. The return value is the number of lines
+actually read. The format of the returned data is discussed under "Data
+formats", above. Don't forget that grayscale and color JPEGs will return
+different data formats!
+
+Image data is returned in top-to-bottom scanline order. If you must write
+out the image in bottom-to-top order, you can use the JPEG library's virtual
+array mechanism to invert the data efficiently. Examples of this can be
+found in the sample application djpeg.
+
+The library maintains a count of the number of scanlines returned so far
+in the output_scanline field of the JPEG object. Usually you can just use
+this variable as the loop counter, so that the loop test looks like
+"while (cinfo.output_scanline < cinfo.output_height)". (Note that the test
+should NOT be against image_height, unless you never use scaling. The
+image_height field is the height of the original unscaled image.)
+The return value always equals the change in the value of output_scanline.
+
+If you don't use a suspending data source, it is safe to assume that
+jpeg_read_scanlines() reads at least one scanline per call, until the
+bottom of the image has been reached.
+
+If you use a buffer larger than one scanline, it is NOT safe to assume that
+jpeg_read_scanlines() fills it. (The current implementation returns only a
+few scanlines per call, no matter how large a buffer you pass.) So you must
+always provide a loop that calls jpeg_read_scanlines() repeatedly until the
+whole image has been read.
+
+
+7. jpeg_finish_decompress(...);
+
+After all the image data has been read, call jpeg_finish_decompress() to
+complete the decompression cycle. This causes working memory associated
+with the JPEG object to be released.
+
+Typical code:
+
+ jpeg_finish_decompress(&cinfo);
+
+If using the stdio source manager, don't forget to close the source stdio
+stream if necessary.
+
+It is an error to call jpeg_finish_decompress() before reading the correct
+total number of scanlines. If you wish to abort decompression, call
+jpeg_abort() as discussed below.
+
+After completing a decompression cycle, you may dispose of the JPEG object as
+discussed next, or you may use it to decompress another image. In that case
+return to step 2 or 3 as appropriate. If you do not change the source
+manager, the next image will be read from the same source.
+
+
+8. Release the JPEG decompression object.
+
+When you are done with a JPEG decompression object, destroy it by calling
+jpeg_destroy_decompress() or jpeg_destroy(). The previous discussion of
+destroying compression objects applies here too.
+
+Typical code:
+
+ jpeg_destroy_decompress(&cinfo);
+
+
+9. Aborting.
+
+You can abort a decompression cycle by calling jpeg_destroy_decompress() or
+jpeg_destroy() if you don't need the JPEG object any more, or
+jpeg_abort_decompress() or jpeg_abort() if you want to reuse the object.
+The previous discussion of aborting compression cycles applies here too.
+
+
+Mechanics of usage: include files, linking, etc
+-----------------------------------------------
+
+Applications using the JPEG library should include the header file jpeglib.h
+to obtain declarations of data types and routines. Before including
+jpeglib.h, include system headers that define at least the typedefs FILE and
+size_t. On ANSI-conforming systems, including <stdio.h> is sufficient; on
+older Unix systems, you may need <sys/types.h> to define size_t.
+
+If the application needs to refer to individual JPEG library error codes, also
+include jerror.h to define those symbols.
+
+jpeglib.h indirectly includes the files jconfig.h and jmorecfg.h. If you are
+installing the JPEG header files in a system directory, you will want to
+install all four files: jpeglib.h, jerror.h, jconfig.h, jmorecfg.h.
+
+The most convenient way to include the JPEG code into your executable program
+is to prepare a library file ("libjpeg.a", or a corresponding name on non-Unix
+machines) and reference it at your link step. If you use only half of the
+library (only compression or only decompression), only that much code will be
+included from the library, unless your linker is hopelessly brain-damaged.
+The supplied makefiles build libjpeg.a automatically (see install.doc).
+
+While you can build the JPEG library as a shared library if the whim strikes
+you, we don't really recommend it. The trouble with shared libraries is that
+at some point you'll probably try to substitute a new version of the library
+without recompiling the calling applications. That generally doesn't work
+because the parameter struct declarations usually change with each new
+version. In other words, the library's API is *not* guaranteed binary
+compatible across versions; we only try to ensure source-code compatibility.
+(In hindsight, it might have been smarter to hide the parameter structs from
+applications and introduce a ton of access functions instead. Too late now,
+however.)
+
+On some systems your application may need to set up a signal handler to ensure
+that temporary files are deleted if the program is interrupted. This is most
+critical if you are on MS-DOS and use the jmemdos.c memory manager back end;
+it will try to grab extended memory for temp files, and that space will NOT be
+freed automatically. See cjpeg.c or djpeg.c for an example signal handler.
+
+It may be worth pointing out that the core JPEG library does not actually
+require the stdio library: only the default source/destination managers and
+error handler need it. You can use the library in a stdio-less environment
+if you replace those modules and use jmemnobs.c (or another memory manager of
+your own devising). More info about the minimum system library requirements
+may be found in jinclude.h.
+
+
+ADVANCED FEATURES
+=================
+
+Compression parameter selection
+-------------------------------
+
+This section describes all the optional parameters you can set for JPEG
+compression, as well as the "helper" routines provided to assist in this
+task. Proper setting of some parameters requires detailed understanding
+of the JPEG standard; if you don't know what a parameter is for, it's best
+not to mess with it! See REFERENCES in the README file for pointers to
+more info about JPEG.
+
+It's a good idea to call jpeg_set_defaults() first, even if you plan to set
+all the parameters; that way your code is more likely to work with future JPEG
+libraries that have additional parameters. For the same reason, we recommend
+you use a helper routine where one is provided, in preference to twiddling
+cinfo fields directly.
+
+The helper routines are:
+
+jpeg_set_defaults (j_compress_ptr cinfo)
+ This routine sets all JPEG parameters to reasonable defaults, using
+ only the input image's color space (field in_color_space, which must
+ already be set in cinfo). Many applications will only need to use
+ this routine and perhaps jpeg_set_quality().
+
+jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
+ Sets the JPEG file's colorspace (field jpeg_color_space) as specified,
+ and sets other color-space-dependent parameters appropriately. See
+ "Special color spaces", below, before using this. A large number of
+ parameters, including all per-component parameters, are set by this
+ routine; if you want to twiddle individual parameters you should call
+ jpeg_set_colorspace() before rather than after.
+
+jpeg_default_colorspace (j_compress_ptr cinfo)
+ Selects an appropriate JPEG colorspace based on cinfo->in_color_space,
+ and calls jpeg_set_colorspace(). This is actually a subroutine of
+ jpeg_set_defaults(). It's broken out in case you want to change
+ just the colorspace-dependent JPEG parameters.
+
+jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline)
+ Constructs JPEG quantization tables appropriate for the indicated
+ quality setting. The quality value is expressed on the 0..100 scale
+ recommended by IJG (cjpeg's "-quality" switch uses this routine).
+ Note that the exact mapping from quality values to tables may change
+ in future IJG releases as more is learned about DCT quantization.
+ If the force_baseline parameter is TRUE, then the quantization table
+ entries are constrained to the range 1..255 for full JPEG baseline
+ compatibility. In the current implementation, this only makes a
+ difference for quality settings below 25, and it effectively prevents
+ very small/low quality files from being generated. The IJG decoder
+ is capable of reading the non-baseline files generated at low quality
+ settings when force_baseline is FALSE, but other decoders may not be.
+
+jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
+ boolean force_baseline)
+ Same as jpeg_set_quality() except that the generated tables are the
+ sample tables given in the JPEC spec section K.1, multiplied by the
+ specified scale factor (which is expressed as a percentage; thus
+ scale_factor = 100 reproduces the spec's tables). Note that larger
+ scale factors give lower quality. This entry point is useful for
+ conforming to the Adobe PostScript DCT conventions, but we do not
+ recommend linear scaling as a user-visible quality scale otherwise.
+ force_baseline again constrains the computed table entries to 1..255.
+
+int jpeg_quality_scaling (int quality)
+ Converts a value on the IJG-recommended quality scale to a linear
+ scaling percentage. Note that this routine may change or go away
+ in future releases --- IJG may choose to adopt a scaling method that
+ can't be expressed as a simple scalar multiplier, in which case the
+ premise of this routine collapses. Caveat user.
+
+jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl,
+ const unsigned int *basic_table,
+ int scale_factor, boolean force_baseline)
+ Allows an arbitrary quantization table to be created. which_tbl
+ indicates which table slot to fill. basic_table points to an array
+ of 64 unsigned ints given in normal array order. These values are
+ multiplied by scale_factor/100 and then clamped to the range 1..65535
+ (or to 1..255 if force_baseline is TRUE).
+ CAUTION: prior to library version 6a, jpeg_add_quant_table expected
+ the basic table to be given in JPEG zigzag order. If you need to
+ write code that works with either older or newer versions of this
+ routine, you must check the library version number. Something like
+ "#if JPEG_LIB_VERSION >= 61" is the right test.
+
+jpeg_simple_progression (j_compress_ptr cinfo)
+ Generates a default scan script for writing a progressive-JPEG file.
+ This is the recommended method of creating a progressive file,
+ unless you want to make a custom scan sequence. You must ensure that
+ the JPEG color space is set correctly before calling this routine.
+
+jpeg_simple_lossless (j_compress_ptr cinfo, int predictor, int point_transform)
+ Generates a default scan script for writing a lossless-JPEG file.
+ This is the recommended method of creating a lossless file,
+ unless you want to make a custom scan sequence. You must ensure that
+ the JPEG color space is set correctly before calling this routine.
+
+
+Compression parameters (cinfo fields) include:
+
+J_DCT_METHOD dct_method
+ Selects the algorithm used for the DCT step. Choices are:
+ JDCT_ISLOW: slow but accurate integer algorithm
+ JDCT_IFAST: faster, less accurate integer method
+ JDCT_FLOAT: floating-point method
+ JDCT_DEFAULT: default method (normally JDCT_ISLOW)
+ JDCT_FASTEST: fastest method (normally JDCT_IFAST)
+ The FLOAT method is very slightly more accurate than the ISLOW method,
+ but may give different results on different machines due to varying
+ roundoff behavior. The integer methods should give the same results
+ on all machines. On machines with sufficiently fast FP hardware, the
+ floating-point method may also be the fastest. The IFAST method is
+ considerably less accurate than the other two; its use is not
+ recommended if high quality is a concern. JDCT_DEFAULT and
+ JDCT_FASTEST are macros configurable by each installation.
+
+J_COLOR_SPACE jpeg_color_space
+int num_components
+ The JPEG color space and corresponding number of components; see
+ "Special color spaces", below, for more info. We recommend using
+ jpeg_set_color_space() if you want to change these.
+
+boolean optimize_coding
+ TRUE causes the compressor to compute optimal Huffman coding tables
+ for the image. This requires an extra pass over the data and
+ therefore costs a good deal of space and time. The default is
+ FALSE, which tells the compressor to use the supplied or default
+ Huffman tables. In most cases optimal tables save only a few percent
+ of file size compared to the default tables. Note that when this is
+ TRUE, you need not supply Huffman tables at all, and any you do
+ supply will be overwritten.
+
+unsigned int restart_interval
+int restart_in_rows
+ To emit restart markers in the JPEG file, set one of these nonzero.
+ Set restart_interval to specify the exact interval in MCU blocks.
+ Set restart_in_rows to specify the interval in MCU rows. (If
+ restart_in_rows is not 0, then restart_interval is set after the
+ image width in MCUs is computed.) Defaults are zero (no restarts).
+ One restart marker per MCU row is often a good choice.
+ NOTE: the overhead of restart markers is higher in grayscale JPEG
+ files than in color files, and MUCH higher in progressive JPEGs.
+ If you use restarts, you may want to use larger intervals in those
+ cases.
+
+const jpeg_scan_info * scan_info
+int num_scans
+ By default, scan_info is NULL; this causes the compressor to write a
+ single-scan sequential JPEG file. If not NULL, scan_info points to
+ an array of scan definition records of length num_scans. The
+ compressor will then write a JPEG file having one scan for each scan
+ definition record. This is used to generate noninterleaved or
+ progressive JPEG files. The library checks that the scan array
+ defines a valid JPEG scan sequence. (jpeg_simple_progression creates
+ a suitable scan definition array for progressive JPEG.) This is
+ discussed further under "Progressive JPEG support".
+
+int smoothing_factor
+ If non-zero, the input image is smoothed; the value should be 1 for
+ minimal smoothing to 100 for maximum smoothing. Consult jcsample.c
+ for details of the smoothing algorithm. The default is zero.
+
+boolean write_JFIF_header
+ If TRUE, a JFIF APP0 marker is emitted. jpeg_set_defaults() and
+ jpeg_set_colorspace() set this TRUE if a JFIF-legal JPEG color space
+ (ie, YCbCr or grayscale) is selected, otherwise FALSE.
+
+UINT8 JFIF_major_version
+UINT8 JFIF_minor_version
+ The version number to be written into the JFIF marker.
+ jpeg_set_defaults() initializes the version to 1.01 (major=minor=1).
+ You should set it to 1.02 (major=1, minor=2) if you plan to write
+ any JFIF 1.02 extension markers.
+
+UINT8 density_unit
+UINT16 X_density
+UINT16 Y_density
+ The resolution information to be written into the JFIF marker;
+ not used otherwise. density_unit may be 0 for unknown,
+ 1 for dots/inch, or 2 for dots/cm. The default values are 0,1,1
+ indicating square pixels of unknown size.
+
+boolean write_Adobe_marker
+ If TRUE, an Adobe APP14 marker is emitted. jpeg_set_defaults() and
+ jpeg_set_colorspace() set this TRUE if JPEG color space RGB, CMYK,
+ or YCCK is selected, otherwise FALSE. It is generally a bad idea
+ to set both write_JFIF_header and write_Adobe_marker. In fact,
+ you probably shouldn't change the default settings at all --- the
+ default behavior ensures that the JPEG file's color space can be
+ recognized by the decoder.
+
+JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS]
+ Pointers to coefficient quantization tables, one per table slot,
+ or NULL if no table is defined for a slot. Usually these should
+ be set via one of the above helper routines; jpeg_add_quant_table()
+ is general enough to define any quantization table. The other
+ routines will set up table slot 0 for luminance quality and table
+ slot 1 for chrominance.
+
+JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS]
+JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS]
+ Pointers to Huffman coding tables, one per table slot, or NULL if
+ no table is defined for a slot. Slots 0 and 1 are filled with the
+ JPEG sample tables by jpeg_set_defaults(). If you need to allocate
+ more table structures, jpeg_alloc_huff_table() may be used.
+ Note that optimal Huffman tables can be computed for an image
+ by setting optimize_coding, as discussed above; there's seldom
+ any need to mess with providing your own Huffman tables.
+
+There are some additional cinfo fields which are not documented here
+because you currently can't change them; for example, you can't set
+arith_code TRUE because arithmetic coding is unsupported.
+
+
+Per-component parameters are stored in the struct cinfo.comp_info[i] for
+component number i. Note that components here refer to components of the
+JPEG color space, *not* the source image color space. A suitably large
+comp_info[] array is allocated by jpeg_set_defaults(); if you choose not
+to use that routine, it's up to you to allocate the array.
+
+int component_id
+ The one-byte identifier code to be recorded in the JPEG file for
+ this component. For the standard color spaces, we recommend you
+ leave the default values alone.
+
+int h_samp_factor
+int v_samp_factor
+ Horizontal and vertical sampling factors for the component; must
+ be 1..4 according to the JPEG standard. Note that larger sampling
+ factors indicate a higher-resolution component; many people find
+ this behavior quite unintuitive. The default values are 2,2 for
+ luminance components and 1,1 for chrominance components, except
+ for grayscale where 1,1 is used.
+
+int quant_tbl_no
+ Quantization table number for component. The default value is
+ 0 for luminance components and 1 for chrominance components.
+
+int dc_tbl_no
+int ac_tbl_no
+ DC and AC entropy coding table numbers. The default values are
+ 0 for luminance components and 1 for chrominance components.
+
+int component_index
+ Must equal the component's index in comp_info[]. (Beginning in
+ release v6, the compressor library will fill this in automatically;
+ you don't have to.)
+
+
+Decompression parameter selection
+---------------------------------
+
+Decompression parameter selection is somewhat simpler than compression
+parameter selection, since all of the JPEG internal parameters are
+recorded in the source file and need not be supplied by the application.
+(Unless you are working with abbreviated files, in which case see
+"Abbreviated datastreams", below.) Decompression parameters control
+the postprocessing done on the image to deliver it in a format suitable
+for the application's use. Many of the parameters control speed/quality
+tradeoffs, in which faster decompression may be obtained at the price of
+a poorer-quality image. The defaults select the highest quality (slowest)
+processing.
+
+The following fields in the JPEG object are set by jpeg_read_header() and
+may be useful to the application in choosing decompression parameters:
+
+JDIMENSION image_width Width and height of image
+JDIMENSION image_height
+int num_components Number of color components
+J_COLOR_SPACE jpeg_color_space Colorspace of image
+boolean saw_JFIF_marker TRUE if a JFIF APP0 marker was seen
+ UINT8 JFIF_major_version Version information from JFIF marker
+ UINT8 JFIF_minor_version
+ UINT8 density_unit Resolution data from JFIF marker
+ UINT16 X_density
+ UINT16 Y_density
+boolean saw_Adobe_marker TRUE if an Adobe APP14 marker was seen
+ UINT8 Adobe_transform Color transform code from Adobe marker
+
+The JPEG color space, unfortunately, is something of a guess since the JPEG
+standard proper does not provide a way to record it. In practice most files
+adhere to the JFIF or Adobe conventions, and the decoder will recognize these
+correctly. See "Special color spaces", below, for more info.
+
+
+The decompression parameters that determine the basic properties of the
+returned image are:
+
+J_COLOR_SPACE out_color_space
+ Output color space. jpeg_read_header() sets an appropriate default
+ based on jpeg_color_space; typically it will be RGB or grayscale.
+ The application can change this field to request output in a different
+ colorspace. For example, set it to JCS_GRAYSCALE to get grayscale
+ output from a color file. (This is useful for previewing: grayscale
+ output is faster than full color since the color components need not
+ be processed.) Note that not all possible color space transforms are
+ currently implemented; you may need to extend jdcolor.c if you want an
+ unusual conversion.
+
+unsigned int scale_num, scale_denom
+ Scale the image by the fraction scale_num/scale_denom. Default is
+ 1/1, or no scaling. Currently, the only supported scaling ratios
+ are 1/1, 1/2, 1/4, and 1/8. (The library design allows for arbitrary
+ scaling ratios but this is not likely to be implemented any time soon.)
+ Smaller scaling ratios permit significantly faster decoding since
+ fewer pixels need be processed and a simpler IDCT method can be used.
+
+boolean quantize_colors
+ If set TRUE, colormapped output will be delivered. Default is FALSE,
+ meaning that full-color output will be delivered.
+
+The next three parameters are relevant only if quantize_colors is TRUE.
+
+int desired_number_of_colors
+ Maximum number of colors to use in generating a library-supplied color
+ map (the actual number of colors is returned in a different field).
+ Default 256. Ignored when the application supplies its own color map.
+
+boolean two_pass_quantize
+ If TRUE, an extra pass over the image is made to select a custom color
+ map for the image. This usually looks a lot better than the one-size-
+ fits-all colormap that is used otherwise. Default is TRUE. Ignored
+ when the application supplies its own color map.
+
+J_DITHER_MODE dither_mode
+ Selects color dithering method. Supported values are:
+ JDITHER_NONE no dithering: fast, very low quality
+ JDITHER_ORDERED ordered dither: moderate speed and quality
+ JDITHER_FS Floyd-Steinberg dither: slow, high quality
+ Default is JDITHER_FS. (At present, ordered dither is implemented
+ only in the single-pass, standard-colormap case. If you ask for
+ ordered dither when two_pass_quantize is TRUE or when you supply
+ an external color map, you'll get F-S dithering.)
+
+When quantize_colors is TRUE, the target color map is described by the next
+two fields. colormap is set to NULL by jpeg_read_header(). The application
+can supply a color map by setting colormap non-NULL and setting
+actual_number_of_colors to the map size. Otherwise, jpeg_start_decompress()
+selects a suitable color map and sets these two fields itself.
+[Implementation restriction: at present, an externally supplied colormap is
+only accepted for 3-component output color spaces.]
+
+JSAMPARRAY colormap
+ The color map, represented as a 2-D pixel array of out_color_components
+ rows and actual_number_of_colors columns. Ignored if not quantizing.
+ CAUTION: if the JPEG library creates its own colormap, the storage
+ pointed to by this field is released by jpeg_finish_decompress().
+ Copy the colormap somewhere else first, if you want to save it.
+
+int actual_number_of_colors
+ The number of colors in the color map.
+
+Additional decompression parameters that the application may set include:
+
+J_DCT_METHOD dct_method
+ Selects the algorithm used for the DCT step. Choices are the same
+ as described above for compression.
+
+boolean do_fancy_upsampling
+ If TRUE, do careful upsampling of chroma components. If FALSE,
+ a faster but sloppier method is used. Default is TRUE. The visual
+ impact of the sloppier method is often very small.
+
+boolean do_block_smoothing
+ If TRUE, interblock smoothing is applied in early stages of decoding
+ progressive JPEG files; if FALSE, not. Default is TRUE. Early
+ progression stages look "fuzzy" with smoothing, "blocky" without.
+ In any case, block smoothing ceases to be applied after the first few
+ AC coefficients are known to full accuracy, so it is relevant only
+ when using buffered-image mode for progressive images.
+
+boolean enable_1pass_quant
+boolean enable_external_quant
+boolean enable_2pass_quant
+ These are significant only in buffered-image mode, which is
+ described in its own section below.
+
+
+The output image dimensions are given by the following fields. These are
+computed from the source image dimensions and the decompression parameters
+by jpeg_start_decompress(). You can also call jpeg_calc_output_dimensions()
+to obtain the values that will result from the current parameter settings.
+This can be useful if you are trying to pick a scaling ratio that will get
+close to a desired target size. It's also important if you are using the
+JPEG library's memory manager to allocate output buffer space, because you
+are supposed to request such buffers *before* jpeg_start_decompress().
+
+JDIMENSION output_width Actual dimensions of output image.
+JDIMENSION output_height
+int out_color_components Number of color components in out_color_space.
+int output_components Number of color components returned.
+int rec_outbuf_height Recommended height of scanline buffer.
+
+When quantizing colors, output_components is 1, indicating a single color map
+index per pixel. Otherwise it equals out_color_components. The output arrays
+are required to be output_width * output_components JSAMPLEs wide.
+
+rec_outbuf_height is the recommended minimum height (in scanlines) of the
+buffer passed to jpeg_read_scanlines(). If the buffer is smaller, the
+library will still work, but time will be wasted due to unnecessary data
+copying. In high-quality modes, rec_outbuf_height is always 1, but some
+faster, lower-quality modes set it to larger values (typically 2 to 4).
+If you are going to ask for a high-speed processing mode, you may as well
+go to the trouble of honoring rec_outbuf_height so as to avoid data copying.
+(An output buffer larger than rec_outbuf_height lines is OK, but won't
+provide any material speed improvement over that height.)
+
+
+Special color spaces
+--------------------
+
+The JPEG standard itself is "color blind" and doesn't specify any particular
+color space. It is customary to convert color data to a luminance/chrominance
+color space before compressing, since this permits greater compression. The
+existing de-facto JPEG file format standards specify YCbCr or grayscale data
+(JFIF), or grayscale, RGB, YCbCr, CMYK, or YCCK (Adobe). For special
+applications such as multispectral images, other color spaces can be used,
+but it must be understood that such files will be unportable.
+
+The JPEG library can handle the most common colorspace conversions (namely
+RGB <=> YCbCr and CMYK <=> YCCK). It can also deal with data of an unknown
+color space, passing it through without conversion. If you deal extensively
+with an unusual color space, you can easily extend the library to understand
+additional color spaces and perform appropriate conversions.
+
+For compression, the source data's color space is specified by field
+in_color_space. This is transformed to the JPEG file's color space given
+by jpeg_color_space. jpeg_set_defaults() chooses a reasonable JPEG color
+space depending on in_color_space, but you can override this by calling
+jpeg_set_colorspace(). Of course you must select a supported transformation.
+jccolor.c currently supports the following transformations:
+ RGB => YCbCr
+ RGB => GRAYSCALE
+ YCbCr => GRAYSCALE
+ CMYK => YCCK
+plus the null transforms: GRAYSCALE => GRAYSCALE, RGB => RGB,
+YCbCr => YCbCr, CMYK => CMYK, YCCK => YCCK, and UNKNOWN => UNKNOWN.
+
+The de-facto file format standards (JFIF and Adobe) specify APPn markers that
+indicate the color space of the JPEG file. It is important to ensure that
+these are written correctly, or omitted if the JPEG file's color space is not
+one of the ones supported by the de-facto standards. jpeg_set_colorspace()
+will set the compression parameters to include or omit the APPn markers
+properly, so long as it is told the truth about the JPEG color space.
+For example, if you are writing some random 3-component color space without
+conversion, don't try to fake out the library by setting in_color_space and
+jpeg_color_space to JCS_YCbCr; use JCS_UNKNOWN. You may want to write an
+APPn marker of your own devising to identify the colorspace --- see "Special
+markers", below.
+
+When told that the color space is UNKNOWN, the library will default to using
+luminance-quality compression parameters for all color components. You may
+well want to change these parameters. See the source code for
+jpeg_set_colorspace(), in jcparam.c, for details.
+
+For decompression, the JPEG file's color space is given in jpeg_color_space,
+and this is transformed to the output color space out_color_space.
+jpeg_read_header's setting of jpeg_color_space can be relied on if the file
+conforms to JFIF or Adobe conventions, but otherwise it is no better than a
+guess. If you know the JPEG file's color space for certain, you can override
+jpeg_read_header's guess by setting jpeg_color_space. jpeg_read_header also
+selects a default output color space based on (its guess of) jpeg_color_space;
+set out_color_space to override this. Again, you must select a supported
+transformation. jdcolor.c currently supports
+ YCbCr => GRAYSCALE
+ YCbCr => RGB
+ GRAYSCALE => RGB
+ YCCK => CMYK
+as well as the null transforms. (Since GRAYSCALE=>RGB is provided, an
+application can force grayscale JPEGs to look like color JPEGs if it only
+wants to handle one case.)
+
+The two-pass color quantizer, jquant2.c, is specialized to handle RGB data
+(it weights distances appropriately for RGB colors). You'll need to modify
+the code if you want to use it for non-RGB output color spaces. Note that
+jquant2.c is used to map to an application-supplied colormap as well as for
+the normal two-pass colormap selection process.
+
+CAUTION: it appears that Adobe Photoshop writes inverted data in CMYK JPEG
+files: 0 represents 100% ink coverage, rather than 0% ink as you'd expect.
+This is arguably a bug in Photoshop, but if you need to work with Photoshop
+CMYK files, you will have to deal with it in your application. We cannot
+"fix" this in the library by inverting the data during the CMYK<=>YCCK
+transform, because that would break other applications, notably Ghostscript.
+Photoshop versions prior to 3.0 write EPS files containing JPEG-encoded CMYK
+data in the same inverted-YCCK representation used in bare JPEG files, but
+the surrounding PostScript code performs an inversion using the PS image
+operator. I am told that Photoshop 3.0 will write uninverted YCCK in
+EPS/JPEG files, and will omit the PS-level inversion. (But the data
+polarity used in bare JPEG files will not change in 3.0.) In either case,
+the JPEG library must not invert the data itself, or else Ghostscript would
+read these EPS files incorrectly.
+
+
+Error handling
+--------------
+
+When the default error handler is used, any error detected inside the JPEG
+routines will cause a message to be printed on stderr, followed by exit().
+You can supply your own error handling routines to override this behavior
+and to control the treatment of nonfatal warnings and trace/debug messages.
+The file example.c illustrates the most common case, which is to have the
+application regain control after an error rather than exiting.
+
+The JPEG library never writes any message directly; it always goes through
+the error handling routines. Three classes of messages are recognized:
+ * Fatal errors: the library cannot continue.
+ * Warnings: the library can continue, but the data is corrupt, and a
+ damaged output image is likely to result.
+ * Trace/informational messages. These come with a trace level indicating
+ the importance of the message; you can control the verbosity of the
+ program by adjusting the maximum trace level that will be displayed.
+
+You may, if you wish, simply replace the entire JPEG error handling module
+(jerror.c) with your own code. However, you can avoid code duplication by
+only replacing some of the routines depending on the behavior you need.
+This is accomplished by calling jpeg_std_error() as usual, but then overriding
+some of the method pointers in the jpeg_error_mgr struct, as illustrated by
+example.c.
+
+All of the error handling routines will receive a pointer to the JPEG object
+(a j_common_ptr which points to either a jpeg_compress_struct or a
+jpeg_decompress_struct; if you need to tell which, test the is_decompressor
+field). This struct includes a pointer to the error manager struct in its
+"err" field. Frequently, custom error handler routines will need to access
+additional data which is not known to the JPEG library or the standard error
+handler. The most convenient way to do this is to embed either the JPEG
+object or the jpeg_error_mgr struct in a larger structure that contains
+additional fields; then casting the passed pointer provides access to the
+additional fields. Again, see example.c for one way to do it. (Beginning
+with IJG version 6b, there is also a void pointer "client_data" in each
+JPEG object, which the application can also use to find related data.
+The library does not touch client_data at all.)
+
+The individual methods that you might wish to override are:
+
+error_exit (j_common_ptr cinfo)
+ Receives control for a fatal error. Information sufficient to
+ generate the error message has been stored in cinfo->err; call
+ output_message to display it. Control must NOT return to the caller;
+ generally this routine will exit() or longjmp() somewhere.
+ Typically you would override this routine to get rid of the exit()
+ default behavior. Note that if you continue processing, you should
+ clean up the JPEG object with jpeg_abort() or jpeg_destroy().
+
+output_message (j_common_ptr cinfo)
+ Actual output of any JPEG message. Override this to send messages
+ somewhere other than stderr. Note that this method does not know
+ how to generate a message, only where to send it.
+
+format_message (j_common_ptr cinfo, char * buffer)
+ Constructs a readable error message string based on the error info
+ stored in cinfo->err. This method is called by output_message. Few
+ applications should need to override this method. One possible
+ reason for doing so is to implement dynamic switching of error message
+ language.
+
+emit_message (j_common_ptr cinfo, int msg_level)
+ Decide whether or not to emit a warning or trace message; if so,
+ calls output_message. The main reason for overriding this method
+ would be to abort on warnings. msg_level is -1 for warnings,
+ 0 and up for trace messages.
+
+Only error_exit() and emit_message() are called from the rest of the JPEG
+library; the other two are internal to the error handler.
+
+The actual message texts are stored in an array of strings which is pointed to
+by the field err->jpeg_message_table. The messages are numbered from 0 to
+err->last_jpeg_message, and it is these code numbers that are used in the
+JPEG library code. You could replace the message texts (for instance, with
+messages in French or German) by changing the message table pointer. See
+jerror.h for the default texts. CAUTION: this table will almost certainly
+change or grow from one library version to the next.
+
+It may be useful for an application to add its own message texts that are
+handled by the same mechanism. The error handler supports a second "add-on"
+message table for this purpose. To define an addon table, set the pointer
+err->addon_message_table and the message numbers err->first_addon_message and
+err->last_addon_message. If you number the addon messages beginning at 1000
+or so, you won't have to worry about conflicts with the library's built-in
+messages. See the sample applications cjpeg/djpeg for an example of using
+addon messages (the addon messages are defined in cderror.h).
+
+Actual invocation of the error handler is done via macros defined in jerror.h:
+ ERREXITn(...) for fatal errors
+ WARNMSn(...) for corrupt-data warnings
+ TRACEMSn(...) for trace and informational messages.
+These macros store the message code and any additional parameters into the
+error handler struct, then invoke the error_exit() or emit_message() method.
+The variants of each macro are for varying numbers of additional parameters.
+The additional parameters are inserted into the generated message using
+standard printf() format codes.
+
+See jerror.h and jerror.c for further details.
+
+
+Compressed data handling (source and destination managers)
+----------------------------------------------------------
+
+The JPEG compression library sends its compressed data to a "destination
+manager" module. The default destination manager just writes the data to a
+stdio stream, but you can provide your own manager to do something else.
+Similarly, the decompression library calls a "source manager" to obtain the
+compressed data; you can provide your own source manager if you want the data
+to come from somewhere other than a stdio stream.
+
+In both cases, compressed data is processed a bufferload at a time: the
+destination or source manager provides a work buffer, and the library invokes
+the manager only when the buffer is filled or emptied. (You could define a
+one-character buffer to force the manager to be invoked for each byte, but
+that would be rather inefficient.) The buffer's size and location are
+controlled by the manager, not by the library. For example, if you desired to
+decompress a JPEG datastream that was all in memory, you could just make the
+buffer pointer and length point to the original data in memory. Then the
+buffer-reload procedure would be invoked only if the decompressor ran off the
+end of the datastream, which would indicate an erroneous datastream.
+
+The work buffer is defined as an array of datatype JOCTET, which is generally
+"char" or "unsigned char". On a machine where char is not exactly 8 bits
+wide, you must define JOCTET as a wider data type and then modify the data
+source and destination modules to transcribe the work arrays into 8-bit units
+on external storage.
+
+A data destination manager struct contains a pointer and count defining the
+next byte to write in the work buffer and the remaining free space:
+
+ JOCTET * next_output_byte; /* => next byte to write in buffer */
+ size_t free_in_buffer; /* # of byte spaces remaining in buffer */
+
+The library increments the pointer and decrements the count until the buffer
+is filled. The manager's empty_output_buffer method must reset the pointer
+and count. The manager is expected to remember the buffer's starting address
+and total size in private fields not visible to the library.
+
+A data destination manager provides three methods:
+
+init_destination (j_compress_ptr cinfo)
+ Initialize destination. This is called by jpeg_start_compress()
+ before any data is actually written. It must initialize
+ next_output_byte and free_in_buffer. free_in_buffer must be
+ initialized to a positive value.
+
+empty_output_buffer (j_compress_ptr cinfo)
+ This is called whenever the buffer has filled (free_in_buffer
+ reaches zero). In typical applications, it should write out the
+ *entire* buffer (use the saved start address and buffer length;
+ ignore the current state of next_output_byte and free_in_buffer).
+ Then reset the pointer & count to the start of the buffer, and
+ return TRUE indicating that the buffer has been dumped.
+ free_in_buffer must be set to a positive value when TRUE is
+ returned. A FALSE return should only be used when I/O suspension is
+ desired (this operating mode is discussed in the next section).
+
+term_destination (j_compress_ptr cinfo)
+ Terminate destination --- called by jpeg_finish_compress() after all
+ data has been written. In most applications, this must flush any
+ data remaining in the buffer. Use either next_output_byte or
+ free_in_buffer to determine how much data is in the buffer.
+
+term_destination() is NOT called by jpeg_abort() or jpeg_destroy(). If you
+want the destination manager to be cleaned up during an abort, you must do it
+yourself.
+
+You will also need code to create a jpeg_destination_mgr struct, fill in its
+method pointers, and insert a pointer to the struct into the "dest" field of
+the JPEG compression object. This can be done in-line in your setup code if
+you like, but it's probably cleaner to provide a separate routine similar to
+the jpeg_stdio_dest() routine of the supplied destination manager.
+
+Decompression source managers follow a parallel design, but with some
+additional frammishes. The source manager struct contains a pointer and count
+defining the next byte to read from the work buffer and the number of bytes
+remaining:
+
+ const JOCTET * next_input_byte; /* => next byte to read from buffer */
+ size_t bytes_in_buffer; /* # of bytes remaining in buffer */
+
+The library increments the pointer and decrements the count until the buffer
+is emptied. The manager's fill_input_buffer method must reset the pointer and
+count. In most applications, the manager must remember the buffer's starting
+address and total size in private fields not visible to the library.
+
+A data source manager provides five methods:
+
+init_source (j_decompress_ptr cinfo)
+ Initialize source. This is called by jpeg_read_header() before any
+ data is actually read. Unlike init_destination(), it may leave
+ bytes_in_buffer set to 0 (in which case a fill_input_buffer() call
+ will occur immediately).
+
+fill_input_buffer (j_decompress_ptr cinfo)
+ This is called whenever bytes_in_buffer has reached zero and more
+ data is wanted. In typical applications, it should read fresh data
+ into the buffer (ignoring the current state of next_input_byte and
+ bytes_in_buffer), reset the pointer & count to the start of the
+ buffer, and return TRUE indicating that the buffer has been reloaded.
+ It is not necessary to fill the buffer entirely, only to obtain at
+ least one more byte. bytes_in_buffer MUST be set to a positive value
+ if TRUE is returned. A FALSE return should only be used when I/O
+ suspension is desired (this mode is discussed in the next section).
+
+skip_input_data (j_decompress_ptr cinfo, long num_bytes)
+ Skip num_bytes worth of data. The buffer pointer and count should
+ be advanced over num_bytes input bytes, refilling the buffer as
+ needed. This is used to skip over a potentially large amount of
+ uninteresting data (such as an APPn marker). In some applications
+ it may be possible to optimize away the reading of the skipped data,
+ but it's not clear that being smart is worth much trouble; large
+ skips are uncommon. bytes_in_buffer may be zero on return.
+ A zero or negative skip count should be treated as a no-op.
+
+resync_to_restart (j_decompress_ptr cinfo, int desired)
+ This routine is called only when the decompressor has failed to find
+ a restart (RSTn) marker where one is expected. Its mission is to
+ find a suitable point for resuming decompression. For most
+ applications, we recommend that you just use the default resync
+ procedure, jpeg_resync_to_restart(). However, if you are able to back
+ up in the input data stream, or if you have a-priori knowledge about
+ the likely location of restart markers, you may be able to do better.
+ Read the read_restart_marker() and jpeg_resync_to_restart() routines
+ in jdmarker.c if you think you'd like to implement your own resync
+ procedure.
+
+term_source (j_decompress_ptr cinfo)
+ Terminate source --- called by jpeg_finish_decompress() after all
+ data has been read. Often a no-op.
+
+For both fill_input_buffer() and skip_input_data(), there is no such thing
+as an EOF return. If the end of the file has been reached, the routine has
+a choice of exiting via ERREXIT() or inserting fake data into the buffer.
+In most cases, generating a warning message and inserting a fake EOI marker
+is the best course of action --- this will allow the decompressor to output
+however much of the image is there. In pathological cases, the decompressor
+may swallow the EOI and again demand data ... just keep feeding it fake EOIs.
+jdatasrc.c illustrates the recommended error recovery behavior.
+
+term_source() is NOT called by jpeg_abort() or jpeg_destroy(). If you want
+the source manager to be cleaned up during an abort, you must do it yourself.
+
+You will also need code to create a jpeg_source_mgr struct, fill in its method
+pointers, and insert a pointer to the struct into the "src" field of the JPEG
+decompression object. This can be done in-line in your setup code if you
+like, but it's probably cleaner to provide a separate routine similar to the
+jpeg_stdio_src() routine of the supplied source manager.
+
+For more information, consult the stdio source and destination managers
+in jdatasrc.c and jdatadst.c.
+
+
+I/O suspension
+--------------
+
+Some applications need to use the JPEG library as an incremental memory-to-
+memory filter: when the compressed data buffer is filled or emptied, they want
+control to return to the outer loop, rather than expecting that the buffer can
+be emptied or reloaded within the data source/destination manager subroutine.
+The library supports this need by providing an "I/O suspension" mode, which we
+describe in this section.
+
+The I/O suspension mode is not a panacea: nothing is guaranteed about the
+maximum amount of time spent in any one call to the library, so it will not
+eliminate response-time problems in single-threaded applications. If you
+need guaranteed response time, we suggest you "bite the bullet" and implement
+a real multi-tasking capability.
+
+To use I/O suspension, cooperation is needed between the calling application
+and the data source or destination manager; you will always need a custom
+source/destination manager. (Please read the previous section if you haven't
+already.) The basic idea is that the empty_output_buffer() or
+fill_input_buffer() routine is a no-op, merely returning FALSE to indicate
+that it has done nothing. Upon seeing this, the JPEG library suspends
+operation and returns to its caller. The surrounding application is
+responsible for emptying or refilling the work buffer before calling the
+JPEG library again.
+
+Compression suspension:
+
+For compression suspension, use an empty_output_buffer() routine that returns
+FALSE; typically it will not do anything else. This will cause the
+compressor to return to the caller of jpeg_write_scanlines(), with the return
+value indicating that not all the supplied scanlines have been accepted.
+The application must make more room in the output buffer, adjust the output
+buffer pointer/count appropriately, and then call jpeg_write_scanlines()
+again, pointing to the first unconsumed scanline.
+
+When forced to suspend, the compressor will backtrack to a convenient stopping
+point (usually the start of the current MCU); it will regenerate some output
+data when restarted. Therefore, although empty_output_buffer() is only
+called when the buffer is filled, you should NOT write out the entire buffer
+after a suspension. Write only the data up to the current position of
+next_output_byte/free_in_buffer. The data beyond that point will be
+regenerated after resumption.
+
+Because of the backtracking behavior, a good-size output buffer is essential
+for efficiency; you don't want the compressor to suspend often. (In fact, an
+overly small buffer could lead to infinite looping, if a single MCU required
+more data than would fit in the buffer.) We recommend a buffer of at least
+several Kbytes. You may want to insert explicit code to ensure that you don't
+call jpeg_write_scanlines() unless there is a reasonable amount of space in
+the output buffer; in other words, flush the buffer before trying to compress
+more data.
+
+The compressor does not allow suspension while it is trying to write JPEG
+markers at the beginning and end of the file. This means that:
+ * At the beginning of a compression operation, there must be enough free
+ space in the output buffer to hold the header markers (typically 600 or
+ so bytes). The recommended buffer size is bigger than this anyway, so
+ this is not a problem as long as you start with an empty buffer. However,
+ this restriction might catch you if you insert large special markers, such
+ as a JFIF thumbnail image, without flushing the buffer afterwards.
+ * When you call jpeg_finish_compress(), there must be enough space in the
+ output buffer to emit any buffered data and the final EOI marker. In the
+ current implementation, half a dozen bytes should suffice for this, but
+ for safety's sake we recommend ensuring that at least 100 bytes are free
+ before calling jpeg_finish_compress().
+
+A more significant restriction is that jpeg_finish_compress() cannot suspend.
+This means you cannot use suspension with multi-pass operating modes, namely
+Huffman code optimization and multiple-scan output. Those modes write the
+whole file during jpeg_finish_compress(), which will certainly result in
+buffer overrun. (Note that this restriction applies only to compression,
+not decompression. The decompressor supports input suspension in all of its
+operating modes.)
+
+Decompression suspension:
+
+For decompression suspension, use a fill_input_buffer() routine that simply
+returns FALSE (except perhaps during error recovery, as discussed below).
+This will cause the decompressor to return to its caller with an indication
+that suspension has occurred. This can happen at four places:
+ * jpeg_read_header(): will return JPEG_SUSPENDED.
+ * jpeg_start_decompress(): will return FALSE, rather than its usual TRUE.
+ * jpeg_read_scanlines(): will return the number of scanlines already
+ completed (possibly 0).
+ * jpeg_finish_decompress(): will return FALSE, rather than its usual TRUE.
+The surrounding application must recognize these cases, load more data into
+the input buffer, and repeat the call. In the case of jpeg_read_scanlines(),
+increment the passed pointers past any scanlines successfully read.
+
+Just as with compression, the decompressor will typically backtrack to a
+convenient restart point before suspending. When fill_input_buffer() is
+called, next_input_byte/bytes_in_buffer point to the current restart point,
+which is where the decompressor will backtrack to if FALSE is returned.
+The data beyond that position must NOT be discarded if you suspend; it needs
+to be re-read upon resumption. In most implementations, you'll need to shift
+this data down to the start of your work buffer and then load more data after
+it. Again, this behavior means that a several-Kbyte work buffer is essential
+for decent performance; furthermore, you should load a reasonable amount of
+new data before resuming decompression. (If you loaded, say, only one new
+byte each time around, you could waste a LOT of cycles.)
+
+The skip_input_data() source manager routine requires special care in a
+suspension scenario. This routine is NOT granted the ability to suspend the
+decompressor; it can decrement bytes_in_buffer to zero, but no more. If the
+requested skip distance exceeds the amount of data currently in the input
+buffer, then skip_input_data() must set bytes_in_buffer to zero and record the
+additional skip distance somewhere else. The decompressor will immediately
+call fill_input_buffer(), which should return FALSE, which will cause a
+suspension return. The surrounding application must then arrange to discard
+the recorded number of bytes before it resumes loading the input buffer.
+(Yes, this design is rather baroque, but it avoids complexity in the far more
+common case where a non-suspending source manager is used.)
+
+If the input data has been exhausted, we recommend that you emit a warning
+and insert dummy EOI markers just as a non-suspending data source manager
+would do. This can be handled either in the surrounding application logic or
+within fill_input_buffer(); the latter is probably more efficient. If
+fill_input_buffer() knows that no more data is available, it can set the
+pointer/count to point to a dummy EOI marker and then return TRUE just as
+though it had read more data in a non-suspending situation.
+
+The decompressor does not attempt to suspend within standard JPEG markers;
+instead it will backtrack to the start of the marker and reprocess the whole
+marker next time. Hence the input buffer must be large enough to hold the
+longest standard marker in the file. Standard JPEG markers should normally
+not exceed a few hundred bytes each (DHT tables are typically the longest).
+We recommend at least a 2K buffer for performance reasons, which is much
+larger than any correct marker is likely to be. For robustness against
+damaged marker length counts, you may wish to insert a test in your
+application for the case that the input buffer is completely full and yet
+the decoder has suspended without consuming any data --- otherwise, if this
+situation did occur, it would lead to an endless loop. (The library can't
+provide this test since it has no idea whether "the buffer is full", or
+even whether there is a fixed-size input buffer.)
+
+The input buffer would need to be 64K to allow for arbitrary COM or APPn
+markers, but these are handled specially: they are either saved into allocated
+memory, or skipped over by calling skip_input_data(). In the former case,
+suspension is handled correctly, and in the latter case, the problem of
+buffer overrun is placed on skip_input_data's shoulders, as explained above.
+Note that if you provide your own marker handling routine for large markers,
+you should consider how to deal with buffer overflow.
+
+Multiple-buffer management:
+
+In some applications it is desirable to store the compressed data in a linked
+list of buffer areas, so as to avoid data copying. This can be handled by
+having empty_output_buffer() or fill_input_buffer() set the pointer and count
+to reference the next available buffer; FALSE is returned only if no more
+buffers are available. Although seemingly straightforward, there is a
+pitfall in this approach: the backtrack that occurs when FALSE is returned
+could back up into an earlier buffer. For example, when fill_input_buffer()
+is called, the current pointer & count indicate the backtrack restart point.
+Since fill_input_buffer() will set the pointer and count to refer to a new
+buffer, the restart position must be saved somewhere else. Suppose a second
+call to fill_input_buffer() occurs in the same library call, and no
+additional input data is available, so fill_input_buffer must return FALSE.
+If the JPEG library has not moved the pointer/count forward in the current
+buffer, then *the correct restart point is the saved position in the prior
+buffer*. Prior buffers may be discarded only after the library establishes
+a restart point within a later buffer. Similar remarks apply for output into
+a chain of buffers.
+
+The library will never attempt to backtrack over a skip_input_data() call,
+so any skipped data can be permanently discarded. You still have to deal
+with the case of skipping not-yet-received data, however.
+
+It's much simpler to use only a single buffer; when fill_input_buffer() is
+called, move any unconsumed data (beyond the current pointer/count) down to
+the beginning of this buffer and then load new data into the remaining buffer
+space. This approach requires a little more data copying but is far easier
+to get right.
+
+
+Progressive JPEG support
+------------------------
+
+Progressive JPEG rearranges the stored data into a series of scans of
+increasing quality. In situations where a JPEG file is transmitted across a
+slow communications link, a decoder can generate a low-quality image very
+quickly from the first scan, then gradually improve the displayed quality as
+more scans are received. The final image after all scans are complete is
+identical to that of a regular (sequential) JPEG file of the same quality
+setting. Progressive JPEG files are often slightly smaller than equivalent
+sequential JPEG files, but the possibility of incremental display is the main
+reason for using progressive JPEG.
+
+The IJG encoder library generates progressive JPEG files when given a
+suitable "scan script" defining how to divide the data into scans.
+Creation of progressive JPEG files is otherwise transparent to the encoder.
+Progressive JPEG files can also be read transparently by the decoder library.
+If the decoding application simply uses the library as defined above, it
+will receive a final decoded image without any indication that the file was
+progressive. Of course, this approach does not allow incremental display.
+To perform incremental display, an application needs to use the decoder
+library's "buffered-image" mode, in which it receives a decoded image
+multiple times.
+
+Each displayed scan requires about as much work to decode as a full JPEG
+image of the same size, so the decoder must be fairly fast in relation to the
+data transmission rate in order to make incremental display useful. However,
+it is possible to skip displaying the image and simply add the incoming bits
+to the decoder's coefficient buffer. This is fast because only Huffman
+decoding need be done, not IDCT, upsampling, colorspace conversion, etc.
+The IJG decoder library allows the application to switch dynamically between
+displaying the image and simply absorbing the incoming bits. A properly
+coded application can automatically adapt the number of display passes to
+suit the time available as the image is received. Also, a final
+higher-quality display cycle can be performed from the buffered data after
+the end of the file is reached.
+
+Progressive compression:
+
+To create a progressive JPEG file (or a multiple-scan sequential JPEG file),
+set the scan_info cinfo field to point to an array of scan descriptors, and
+perform compression as usual. Instead of constructing your own scan list,
+you can call the jpeg_simple_progression() helper routine to create a
+recommended progression sequence; this method should be used by all
+applications that don't want to get involved in the nitty-gritty of
+progressive scan sequence design. (If you want to provide user control of
+scan sequences, you may wish to borrow the scan script reading code found
+in rdswitch.c, so that you can read scan script files just like cjpeg's.)
+When scan_info is not NULL, the compression library will store DCT'd data
+into a buffer array as jpeg_write_scanlines() is called, and will emit all
+the requested scans during jpeg_finish_compress(). This implies that
+multiple-scan output cannot be created with a suspending data destination
+manager, since jpeg_finish_compress() does not support suspension. We
+should also note that the compressor currently forces Huffman optimization
+mode when creating a progressive JPEG file, because the default Huffman
+tables are unsuitable for progressive files.
+
+Progressive decompression:
+
+When buffered-image mode is not used, the decoder library will read all of
+a multi-scan file during jpeg_start_decompress(), so that it can provide a
+final decoded image. (Here "multi-scan" means either progressive or
+multi-scan sequential.) This makes multi-scan files transparent to the
+decoding application. However, existing applications that used suspending
+input with version 5 of the IJG library will need to be modified to check
+for a suspension return from jpeg_start_decompress().
+
+To perform incremental display, an application must use the library's
+buffered-image mode. This is described in the next section.
+
+
+Buffered-image mode
+-------------------
+
+In buffered-image mode, the library stores the partially decoded image in a
+coefficient buffer, from which it can be read out as many times as desired.
+This mode is typically used for incremental display of progressive JPEG files,
+but it can be used with any JPEG file. Each scan of a progressive JPEG file
+adds more data (more detail) to the buffered image. The application can
+display in lockstep with the source file (one display pass per input scan),
+or it can allow input processing to outrun display processing. By making
+input and display processing run independently, it is possible for the
+application to adapt progressive display to a wide range of data transmission
+rates.
+
+The basic control flow for buffered-image decoding is
+
+ jpeg_create_decompress()
+ set data source
+ jpeg_read_header()
+ set overall decompression parameters
+ cinfo.buffered_image = TRUE; /* select buffered-image mode */
+ jpeg_start_decompress()
+ for (each output pass) {
+ adjust output decompression parameters if required
+ jpeg_start_output() /* start a new output pass */
+ for (all scanlines in image) {
+ jpeg_read_scanlines()
+ display scanlines
+ }
+ jpeg_finish_output() /* terminate output pass */
+ }
+ jpeg_finish_decompress()
+ jpeg_destroy_decompress()
+
+This differs from ordinary unbuffered decoding in that there is an additional
+level of looping. The application can choose how many output passes to make
+and how to display each pass.
+
+The simplest approach to displaying progressive images is to do one display
+pass for each scan appearing in the input file. In this case the outer loop
+condition is typically
+ while (! jpeg_input_complete(&cinfo))
+and the start-output call should read
+ jpeg_start_output(&cinfo, cinfo.input_scan_number);
+The second parameter to jpeg_start_output() indicates which scan of the input
+file is to be displayed; the scans are numbered starting at 1 for this
+purpose. (You can use a loop counter starting at 1 if you like, but using
+the library's input scan counter is easier.) The library automatically reads
+data as necessary to complete each requested scan, and jpeg_finish_output()
+advances to the next scan or end-of-image marker (hence input_scan_number
+will be incremented by the time control arrives back at jpeg_start_output()).
+With this technique, data is read from the input file only as needed, and
+input and output processing run in lockstep.
+
+After reading the final scan and reaching the end of the input file, the
+buffered image remains available; it can be read additional times by
+repeating the jpeg_start_output()/jpeg_read_scanlines()/jpeg_finish_output()
+sequence. For example, a useful technique is to use fast one-pass color
+quantization for display passes made while the image is arriving, followed by
+a final display pass using two-pass quantization for highest quality. This
+is done by changing the library parameters before the final output pass.
+Changing parameters between passes is discussed in detail below.
+
+In general the last scan of a progressive file cannot be recognized as such
+until after it is read, so a post-input display pass is the best approach if
+you want special processing in the final pass.
+
+When done with the image, be sure to call jpeg_finish_decompress() to release
+the buffered image (or just use jpeg_destroy_decompress()).
+
+If input data arrives faster than it can be displayed, the application can
+cause the library to decode input data in advance of what's needed to produce
+output. This is done by calling the routine jpeg_consume_input().
+The return value is one of the following:
+ JPEG_REACHED_SOS: reached an SOS marker (the start of a new scan)
+ JPEG_REACHED_EOI: reached the EOI marker (end of image)
+ JPEG_ROW_COMPLETED: completed reading one MCU row of compressed data
+ JPEG_SCAN_COMPLETED: completed reading last MCU row of current scan
+ JPEG_SUSPENDED: suspended before completing any of the above
+(JPEG_SUSPENDED can occur only if a suspending data source is used.) This
+routine can be called at any time after initializing the JPEG object. It
+reads some additional data and returns when one of the indicated significant
+events occurs. (If called after the EOI marker is reached, it will
+immediately return JPEG_REACHED_EOI without attempting to read more data.)
+
+The library's output processing will automatically call jpeg_consume_input()
+whenever the output processing overtakes the input; thus, simple lockstep
+display requires no direct calls to jpeg_consume_input(). But by adding
+calls to jpeg_consume_input(), you can absorb data in advance of what is
+being displayed. This has two benefits:
+ * You can limit buildup of unprocessed data in your input buffer.
+ * You can eliminate extra display passes by paying attention to the
+ state of the library's input processing.
+
+The first of these benefits only requires interspersing calls to
+jpeg_consume_input() with your display operations and any other processing
+you may be doing. To avoid wasting cycles due to backtracking, it's best to
+call jpeg_consume_input() only after a hundred or so new bytes have arrived.
+This is discussed further under "I/O suspension", above. (Note: the JPEG
+library currently is not thread-safe. You must not call jpeg_consume_input()
+from one thread of control if a different library routine is working on the
+same JPEG object in another thread.)
+
+When input arrives fast enough that more than one new scan is available
+before you start a new output pass, you may as well skip the output pass
+corresponding to the completed scan. This occurs for free if you pass
+cinfo.input_scan_number as the target scan number to jpeg_start_output().
+The input_scan_number field is simply the index of the scan currently being
+consumed by the input processor. You can ensure that this is up-to-date by
+emptying the input buffer just before calling jpeg_start_output(): call
+jpeg_consume_input() repeatedly until it returns JPEG_SUSPENDED or
+JPEG_REACHED_EOI.
+
+The target scan number passed to jpeg_start_output() is saved in the
+cinfo.output_scan_number field. The library's output processing calls
+jpeg_consume_input() whenever the current input scan number and row within
+that scan is less than or equal to the current output scan number and row.
+Thus, input processing can "get ahead" of the output processing but is not
+allowed to "fall behind". You can achieve several different effects by
+manipulating this interlock rule. For example, if you pass a target scan
+number greater than the current input scan number, the output processor will
+wait until that scan starts to arrive before producing any output. (To avoid
+an infinite loop, the target scan number is automatically reset to the last
+scan number when the end of image is reached. Thus, if you specify a large
+target scan number, the library will just absorb the entire input file and
+then perform an output pass. This is effectively the same as what
+jpeg_start_decompress() does when you don't select buffered-image mode.)
+When you pass a target scan number equal to the current input scan number,
+the image is displayed no faster than the current input scan arrives. The
+final possibility is to pass a target scan number less than the current input
+scan number; this disables the input/output interlock and causes the output
+processor to simply display whatever it finds in the image buffer, without
+waiting for input. (However, the library will not accept a target scan
+number less than one, so you can't avoid waiting for the first scan.)
+
+When data is arriving faster than the output display processing can advance
+through the image, jpeg_consume_input() will store data into the buffered
+image beyond the point at which the output processing is reading data out
+again. If the input arrives fast enough, it may "wrap around" the buffer to
+the point where the input is more than one whole scan ahead of the output.
+If the output processing simply proceeds through its display pass without
+paying attention to the input, the effect seen on-screen is that the lower
+part of the image is one or more scans better in quality than the upper part.
+Then, when the next output scan is started, you have a choice of what target
+scan number to use. The recommended choice is to use the current input scan
+number at that time, which implies that you've skipped the output scans
+corresponding to the input scans that were completed while you processed the
+previous output scan. In this way, the decoder automatically adapts its
+speed to the arriving data, by skipping output scans as necessary to keep up
+with the arriving data.
+
+When using this strategy, you'll want to be sure that you perform a final
+output pass after receiving all the data; otherwise your last display may not
+be full quality across the whole screen. So the right outer loop logic is
+something like this:
+ do {
+ absorb any waiting input by calling jpeg_consume_input()
+ final_pass = jpeg_input_complete(&cinfo);
+ adjust output decompression parameters if required
+ jpeg_start_output(&cinfo, cinfo.input_scan_number);
+ ...
+ jpeg_finish_output()
+ } while (! final_pass);
+rather than quitting as soon as jpeg_input_complete() returns TRUE. This
+arrangement makes it simple to use higher-quality decoding parameters
+for the final pass. But if you don't want to use special parameters for
+the final pass, the right loop logic is like this:
+ for (;;) {
+ absorb any waiting input by calling jpeg_consume_input()
+ jpeg_start_output(&cinfo, cinfo.input_scan_number);
+ ...
+ jpeg_finish_output()
+ if (jpeg_input_complete(&cinfo) &&
+ cinfo.input_scan_number == cinfo.output_scan_number)
+ break;
+ }
+In this case you don't need to know in advance whether an output pass is to
+be the last one, so it's not necessary to have reached EOF before starting
+the final output pass; rather, what you want to test is whether the output
+pass was performed in sync with the final input scan. This form of the loop
+will avoid an extra output pass whenever the decoder is able (or nearly able)
+to keep up with the incoming data.
+
+When the data transmission speed is high, you might begin a display pass,
+then find that much or all of the file has arrived before you can complete
+the pass. (You can detect this by noting the JPEG_REACHED_EOI return code
+from jpeg_consume_input(), or equivalently by testing jpeg_input_complete().)
+In this situation you may wish to abort the current display pass and start a
+new one using the newly arrived information. To do so, just call
+jpeg_finish_output() and then start a new pass with jpeg_start_output().
+
+A variant strategy is to abort and restart display if more than one complete
+scan arrives during an output pass; this can be detected by noting
+JPEG_REACHED_SOS returns and/or examining cinfo.input_scan_number. This
+idea should be employed with caution, however, since the display process
+might never get to the bottom of the image before being aborted, resulting
+in the lower part of the screen being several passes worse than the upper.
+In most cases it's probably best to abort an output pass only if the whole
+file has arrived and you want to begin the final output pass immediately.
+
+When receiving data across a communication link, we recommend always using
+the current input scan number for the output target scan number; if a
+higher-quality final pass is to be done, it should be started (aborting any
+incomplete output pass) as soon as the end of file is received. However,
+many other strategies are possible. For example, the application can examine
+the parameters of the current input scan and decide whether to display it or
+not. If the scan contains only chroma data, one might choose not to use it
+as the target scan, expecting that the scan will be small and will arrive
+quickly. To skip to the next scan, call jpeg_consume_input() until it
+returns JPEG_REACHED_SOS or JPEG_REACHED_EOI. Or just use the next higher
+number as the target scan for jpeg_start_output(); but that method doesn't
+let you inspect the next scan's parameters before deciding to display it.
+
+
+In buffered-image mode, jpeg_start_decompress() never performs input and
+thus never suspends. An application that uses input suspension with
+buffered-image mode must be prepared for suspension returns from these
+routines:
+* jpeg_start_output() performs input only if you request 2-pass quantization
+ and the target scan isn't fully read yet. (This is discussed below.)
+* jpeg_read_scanlines(), as always, returns the number of scanlines that it
+ was able to produce before suspending.
+* jpeg_finish_output() will read any markers following the target scan,
+ up to the end of the file or the SOS marker that begins another scan.
+ (But it reads no input if jpeg_consume_input() has already reached the
+ end of the file or a SOS marker beyond the target output scan.)
+* jpeg_finish_decompress() will read until the end of file, and thus can
+ suspend if the end hasn't already been reached (as can be tested by
+ calling jpeg_input_complete()).
+jpeg_start_output(), jpeg_finish_output(), and jpeg_finish_decompress()
+all return TRUE if they completed their tasks, FALSE if they had to suspend.
+In the event of a FALSE return, the application must load more input data
+and repeat the call. Applications that use non-suspending data sources need
+not check the return values of these three routines.
+
+
+It is possible to change decoding parameters between output passes in the
+buffered-image mode. The decoder library currently supports only very
+limited changes of parameters. ONLY THE FOLLOWING parameter changes are
+allowed after jpeg_start_decompress() is called:
+* dct_method can be changed before each call to jpeg_start_output().
+ For example, one could use a fast DCT method for early scans, changing
+ to a higher quality method for the final scan.
+* dither_mode can be changed before each call to jpeg_start_output();
+ of course this has no impact if not using color quantization. Typically
+ one would use ordered dither for initial passes, then switch to
+ Floyd-Steinberg dither for the final pass. Caution: changing dither mode
+ can cause more memory to be allocated by the library. Although the amount
+ of memory involved is not large (a scanline or so), it may cause the
+ initial max_memory_to_use specification to be exceeded, which in the worst
+ case would result in an out-of-memory failure.
+* do_block_smoothing can be changed before each call to jpeg_start_output().
+ This setting is relevant only when decoding a progressive JPEG image.
+ During the first DC-only scan, block smoothing provides a very "fuzzy" look
+ instead of the very "blocky" look seen without it; which is better seems a
+ matter of personal taste. But block smoothing is nearly always a win
+ during later stages, especially when decoding a successive-approximation
+ image: smoothing helps to hide the slight blockiness that otherwise shows
+ up on smooth gradients until the lowest coefficient bits are sent.
+* Color quantization mode can be changed under the rules described below.
+ You *cannot* change between full-color and quantized output (because that
+ would alter the required I/O buffer sizes), but you can change which
+ quantization method is used.
+
+When generating color-quantized output, changing quantization method is a
+very useful way of switching between high-speed and high-quality display.
+The library allows you to change among its three quantization methods:
+1. Single-pass quantization to a fixed color cube.
+ Selected by cinfo.two_pass_quantize = FALSE and cinfo.colormap = NULL.
+2. Single-pass quantization to an application-supplied colormap.
+ Selected by setting cinfo.colormap to point to the colormap (the value of
+ two_pass_quantize is ignored); also set cinfo.actual_number_of_colors.
+3. Two-pass quantization to a colormap chosen specifically for the image.
+ Selected by cinfo.two_pass_quantize = TRUE and cinfo.colormap = NULL.
+ (This is the default setting selected by jpeg_read_header, but it is
+ probably NOT what you want for the first pass of progressive display!)
+These methods offer successively better quality and lesser speed. However,
+only the first method is available for quantizing in non-RGB color spaces.
+
+IMPORTANT: because the different quantizer methods have very different
+working-storage requirements, the library requires you to indicate which
+one(s) you intend to use before you call jpeg_start_decompress(). (If we did
+not require this, the max_memory_to_use setting would be a complete fiction.)
+You do this by setting one or more of these three cinfo fields to TRUE:
+ enable_1pass_quant Fixed color cube colormap
+ enable_external_quant Externally-supplied colormap
+ enable_2pass_quant Two-pass custom colormap
+All three are initialized FALSE by jpeg_read_header(). But
+jpeg_start_decompress() automatically sets TRUE the one selected by the
+current two_pass_quantize and colormap settings, so you only need to set the
+enable flags for any other quantization methods you plan to change to later.
+
+After setting the enable flags correctly at jpeg_start_decompress() time, you
+can change to any enabled quantization method by setting two_pass_quantize
+and colormap properly just before calling jpeg_start_output(). The following
+special rules apply:
+1. You must explicitly set cinfo.colormap to NULL when switching to 1-pass
+ or 2-pass mode from a different mode, or when you want the 2-pass
+ quantizer to be re-run to generate a new colormap.
+2. To switch to an external colormap, or to change to a different external
+ colormap than was used on the prior pass, you must call
+ jpeg_new_colormap() after setting cinfo.colormap.
+NOTE: if you want to use the same colormap as was used in the prior pass,
+you should not do either of these things. This will save some nontrivial
+switchover costs.
+(These requirements exist because cinfo.colormap will always be non-NULL
+after completing a prior output pass, since both the 1-pass and 2-pass
+quantizers set it to point to their output colormaps. Thus you have to
+do one of these two things to notify the library that something has changed.
+Yup, it's a bit klugy, but it's necessary to do it this way for backwards
+compatibility.)
+
+Note that in buffered-image mode, the library generates any requested colormap
+during jpeg_start_output(), not during jpeg_start_decompress().
+
+When using two-pass quantization, jpeg_start_output() makes a pass over the
+buffered image to determine the optimum color map; it therefore may take a
+significant amount of time, whereas ordinarily it does little work. The
+progress monitor hook is called during this pass, if defined. It is also
+important to realize that if the specified target scan number is greater than
+or equal to the current input scan number, jpeg_start_output() will attempt
+to consume input as it makes this pass. If you use a suspending data source,
+you need to check for a FALSE return from jpeg_start_output() under these
+conditions. The combination of 2-pass quantization and a not-yet-fully-read
+target scan is the only case in which jpeg_start_output() will consume input.
+
+
+Application authors who support buffered-image mode may be tempted to use it
+for all JPEG images, even single-scan ones. This will work, but it is
+inefficient: there is no need to create an image-sized coefficient buffer for
+single-scan images. Requesting buffered-image mode for such an image wastes
+memory. Worse, it can cost time on large images, since the buffered data has
+to be swapped out or written to a temporary file. If you are concerned about
+maximum performance on baseline JPEG files, you should use buffered-image
+mode only when the incoming file actually has multiple scans. This can be
+tested by calling jpeg_has_multiple_scans(), which will return a correct
+result at any time after jpeg_read_header() completes.
+
+It is also worth noting that when you use jpeg_consume_input() to let input
+processing get ahead of output processing, the resulting pattern of access to
+the coefficient buffer is quite nonsequential. It's best to use the memory
+manager jmemnobs.c if you can (ie, if you have enough real or virtual main
+memory). If not, at least make sure that max_memory_to_use is set as high as
+possible. If the JPEG memory manager has to use a temporary file, you will
+probably see a lot of disk traffic and poor performance. (This could be
+improved with additional work on the memory manager, but we haven't gotten
+around to it yet.)
+
+In some applications it may be convenient to use jpeg_consume_input() for all
+input processing, including reading the initial markers; that is, you may
+wish to call jpeg_consume_input() instead of jpeg_read_header() during
+startup. This works, but note that you must check for JPEG_REACHED_SOS and
+JPEG_REACHED_EOI return codes as the equivalent of jpeg_read_header's codes.
+Once the first SOS marker has been reached, you must call
+jpeg_start_decompress() before jpeg_consume_input() will consume more input;
+it'll just keep returning JPEG_REACHED_SOS until you do. If you read a
+tables-only file this way, jpeg_consume_input() will return JPEG_REACHED_EOI
+without ever returning JPEG_REACHED_SOS; be sure to check for this case.
+If this happens, the decompressor will not read any more input until you call
+jpeg_abort() to reset it. It is OK to call jpeg_consume_input() even when not
+using buffered-image mode, but in that case it's basically a no-op after the
+initial markers have been read: it will just return JPEG_SUSPENDED.
+
+
+Abbreviated datastreams and multiple images
+-------------------------------------------
+
+A JPEG compression or decompression object can be reused to process multiple
+images. This saves a small amount of time per image by eliminating the
+"create" and "destroy" operations, but that isn't the real purpose of the
+feature. Rather, reuse of an object provides support for abbreviated JPEG
+datastreams. Object reuse can also simplify processing a series of images in
+a single input or output file. This section explains these features.
+
+A JPEG file normally contains several hundred bytes worth of quantization
+and Huffman tables. In a situation where many images will be stored or
+transmitted with identical tables, this may represent an annoying overhead.
+The JPEG standard therefore permits tables to be omitted. The standard
+defines three classes of JPEG datastreams:
+ * "Interchange" datastreams contain an image and all tables needed to decode
+ the image. These are the usual kind of JPEG file.
+ * "Abbreviated image" datastreams contain an image, but are missing some or
+ all of the tables needed to decode that image.
+ * "Abbreviated table specification" (henceforth "tables-only") datastreams
+ contain only table specifications.
+To decode an abbreviated image, it is necessary to load the missing table(s)
+into the decoder beforehand. This can be accomplished by reading a separate
+tables-only file. A variant scheme uses a series of images in which the first
+image is an interchange (complete) datastream, while subsequent ones are
+abbreviated and rely on the tables loaded by the first image. It is assumed
+that once the decoder has read a table, it will remember that table until a
+new definition for the same table number is encountered.
+
+It is the application designer's responsibility to figure out how to associate
+the correct tables with an abbreviated image. While abbreviated datastreams
+can be useful in a closed environment, their use is strongly discouraged in
+any situation where data exchange with other applications might be needed.
+Caveat designer.
+
+The JPEG library provides support for reading and writing any combination of
+tables-only datastreams and abbreviated images. In both compression and
+decompression objects, a quantization or Huffman table will be retained for
+the lifetime of the object, unless it is overwritten by a new table definition.
+
+
+To create abbreviated image datastreams, it is only necessary to tell the
+compressor not to emit some or all of the tables it is using. Each
+quantization and Huffman table struct contains a boolean field "sent_table",
+which normally is initialized to FALSE. For each table used by the image, the
+header-writing process emits the table and sets sent_table = TRUE unless it is
+already TRUE. (In normal usage, this prevents outputting the same table
+definition multiple times, as would otherwise occur because the chroma
+components typically share tables.) Thus, setting this field to TRUE before
+calling jpeg_start_compress() will prevent the table from being written at
+all.
+
+If you want to create a "pure" abbreviated image file containing no tables,
+just call "jpeg_suppress_tables(&cinfo, TRUE)" after constructing all the
+tables. If you want to emit some but not all tables, you'll need to set the
+individual sent_table fields directly.
+
+To create an abbreviated image, you must also call jpeg_start_compress()
+with a second parameter of FALSE, not TRUE. Otherwise jpeg_start_compress()
+will force all the sent_table fields to FALSE. (This is a safety feature to
+prevent abbreviated images from being created accidentally.)
+
+To create a tables-only file, perform the same parameter setup that you
+normally would, but instead of calling jpeg_start_compress() and so on, call
+jpeg_write_tables(&cinfo). This will write an abbreviated datastream
+containing only SOI, DQT and/or DHT markers, and EOI. All the quantization
+and Huffman tables that are currently defined in the compression object will
+be emitted unless their sent_tables flag is already TRUE, and then all the
+sent_tables flags will be set TRUE.
+
+A sure-fire way to create matching tables-only and abbreviated image files
+is to proceed as follows:
+
+ create JPEG compression object
+ set JPEG parameters
+ set destination to tables-only file
+ jpeg_write_tables(&cinfo);
+ set destination to image file
+ jpeg_start_compress(&cinfo, FALSE);
+ write data...
+ jpeg_finish_compress(&cinfo);
+
+Since the JPEG parameters are not altered between writing the table file and
+the abbreviated image file, the same tables are sure to be used. Of course,
+you can repeat the jpeg_start_compress() ... jpeg_finish_compress() sequence
+many times to produce many abbreviated image files matching the table file.
+
+You cannot suppress output of the computed Huffman tables when Huffman
+optimization is selected. (If you could, there'd be no way to decode the
+image...) Generally, you don't want to set optimize_coding = TRUE when
+you are trying to produce abbreviated files.
+
+In some cases you might want to compress an image using tables which are
+not stored in the application, but are defined in an interchange or
+tables-only file readable by the application. This can be done by setting up
+a JPEG decompression object to read the specification file, then copying the
+tables into your compression object. See jpeg_copy_critical_parameters()
+for an example of copying quantization tables.
+
+
+To read abbreviated image files, you simply need to load the proper tables
+into the decompression object before trying to read the abbreviated image.
+If the proper tables are stored in the application program, you can just
+allocate the table structs and fill in their contents directly. For example,
+to load a fixed quantization table into table slot "n":
+
+ if (cinfo.quant_tbl_ptrs[n] == NULL)
+ cinfo.quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) &cinfo);
+ quant_ptr = cinfo.quant_tbl_ptrs[n]; /* quant_ptr is JQUANT_TBL* */
+ for (i = 0; i < 64; i++) {
+ /* Qtable[] is desired quantization table, in natural array order */
+ quant_ptr->quantval[i] = Qtable[i];
+ }
+
+Code to load a fixed Huffman table is typically (for AC table "n"):
+
+ if (cinfo.ac_huff_tbl_ptrs[n] == NULL)
+ cinfo.ac_huff_tbl_ptrs[n] = jpeg_alloc_huff_table((j_common_ptr) &cinfo);
+ huff_ptr = cinfo.ac_huff_tbl_ptrs[n]; /* huff_ptr is JHUFF_TBL* */
+ for (i = 1; i <= 16; i++) {
+ /* counts[i] is number of Huffman codes of length i bits, i=1..16 */
+ huff_ptr->bits[i] = counts[i];
+ }
+ for (i = 0; i < 256; i++) {
+ /* symbols[] is the list of Huffman symbols, in code-length order */
+ huff_ptr->huffval[i] = symbols[i];
+ }
+
+(Note that trying to set cinfo.quant_tbl_ptrs[n] to point directly at a
+constant JQUANT_TBL object is not safe. If the incoming file happened to
+contain a quantization table definition, your master table would get
+overwritten! Instead allocate a working table copy and copy the master table
+into it, as illustrated above. Ditto for Huffman tables, of course.)
+
+You might want to read the tables from a tables-only file, rather than
+hard-wiring them into your application. The jpeg_read_header() call is
+sufficient to read a tables-only file. You must pass a second parameter of
+FALSE to indicate that you do not require an image to be present. Thus, the
+typical scenario is
+
+ create JPEG decompression object
+ set source to tables-only file
+ jpeg_read_header(&cinfo, FALSE);
+ set source to abbreviated image file
+ jpeg_read_header(&cinfo, TRUE);
+ set decompression parameters
+ jpeg_start_decompress(&cinfo);
+ read data...
+ jpeg_finish_decompress(&cinfo);
+
+In some cases, you may want to read a file without knowing whether it contains
+an image or just tables. In that case, pass FALSE and check the return value
+from jpeg_read_header(): it will be JPEG_HEADER_OK if an image was found,
+JPEG_HEADER_TABLES_ONLY if only tables were found. (A third return value,
+JPEG_SUSPENDED, is possible when using a suspending data source manager.)
+Note that jpeg_read_header() will not complain if you read an abbreviated
+image for which you haven't loaded the missing tables; the missing-table check
+occurs later, in jpeg_start_decompress().
+
+
+It is possible to read a series of images from a single source file by
+repeating the jpeg_read_header() ... jpeg_finish_decompress() sequence,
+without releasing/recreating the JPEG object or the data source module.
+(If you did reinitialize, any partial bufferload left in the data source
+buffer at the end of one image would be discarded, causing you to lose the
+start of the next image.) When you use this method, stored tables are
+automatically carried forward, so some of the images can be abbreviated images
+that depend on tables from earlier images.
+
+If you intend to write a series of images into a single destination file,
+you might want to make a specialized data destination module that doesn't
+flush the output buffer at term_destination() time. This would speed things
+up by some trifling amount. Of course, you'd need to remember to flush the
+buffer after the last image. You can make the later images be abbreviated
+ones by passing FALSE to jpeg_start_compress().
+
+
+Special markers
+---------------
+
+Some applications may need to insert or extract special data in the JPEG
+datastream. The JPEG standard provides marker types "COM" (comment) and
+"APP0" through "APP15" (application) to hold application-specific data.
+Unfortunately, the use of these markers is not specified by the standard.
+COM markers are fairly widely used to hold user-supplied text. The JFIF file
+format spec uses APP0 markers with specified initial strings to hold certain
+data. Adobe applications use APP14 markers beginning with the string "Adobe"
+for miscellaneous data. Other APPn markers are rarely seen, but might
+contain almost anything.
+
+If you wish to store user-supplied text, we recommend you use COM markers
+and place readable 7-bit ASCII text in them. Newline conventions are not
+standardized --- expect to find LF (Unix style), CR/LF (DOS style), or CR
+(Mac style). A robust COM reader should be able to cope with random binary
+garbage, including nulls, since some applications generate COM markers
+containing non-ASCII junk. (But yours should not be one of them.)
+
+For program-supplied data, use an APPn marker, and be sure to begin it with an
+identifying string so that you can tell whether the marker is actually yours.
+It's probably best to avoid using APP0 or APP14 for any private markers.
+(NOTE: the upcoming SPIFF standard will use APP8 markers; we recommend you
+not use APP8 markers for any private purposes, either.)
+
+Keep in mind that at most 65533 bytes can be put into one marker, but you
+can have as many markers as you like.
+
+By default, the IJG compression library will write a JFIF APP0 marker if the
+selected JPEG colorspace is grayscale or YCbCr, or an Adobe APP14 marker if
+the selected colorspace is RGB, CMYK, or YCCK. You can disable this, but
+we don't recommend it. The decompression library will recognize JFIF and
+Adobe markers and will set the JPEG colorspace properly when one is found.
+
+
+You can write special markers immediately following the datastream header by
+calling jpeg_write_marker() after jpeg_start_compress() and before the first
+call to jpeg_write_scanlines(). When you do this, the markers appear after
+the SOI and the JFIF APP0 and Adobe APP14 markers (if written), but before
+all else. Specify the marker type parameter as "JPEG_COM" for COM or
+"JPEG_APP0 + n" for APPn. (Actually, jpeg_write_marker will let you write
+any marker type, but we don't recommend writing any other kinds of marker.)
+For example, to write a user comment string pointed to by comment_text:
+ jpeg_write_marker(cinfo, JPEG_COM, comment_text, strlen(comment_text));
+
+If it's not convenient to store all the marker data in memory at once,
+you can instead call jpeg_write_m_header() followed by multiple calls to
+jpeg_write_m_byte(). If you do it this way, it's your responsibility to
+call jpeg_write_m_byte() exactly the number of times given in the length
+parameter to jpeg_write_m_header(). (This method lets you empty the
+output buffer partway through a marker, which might be important when
+using a suspending data destination module. In any case, if you are using
+a suspending destination, you should flush its buffer after inserting
+any special markers. See "I/O suspension".)
+
+Or, if you prefer to synthesize the marker byte sequence yourself,
+you can just cram it straight into the data destination module.
+
+If you are writing JFIF 1.02 extension markers (thumbnail images), don't
+forget to set cinfo.JFIF_minor_version = 2 so that the encoder will write the
+correct JFIF version number in the JFIF header marker. The library's default
+is to write version 1.01, but that's wrong if you insert any 1.02 extension
+markers. (We could probably get away with just defaulting to 1.02, but there
+used to be broken decoders that would complain about unknown minor version
+numbers. To reduce compatibility risks it's safest not to write 1.02 unless
+you are actually using 1.02 extensions.)
+
+
+When reading, two methods of handling special markers are available:
+1. You can ask the library to save the contents of COM and/or APPn markers
+into memory, and then examine them at your leisure afterwards.
+2. You can supply your own routine to process COM and/or APPn markers
+on-the-fly as they are read.
+The first method is simpler to use, especially if you are using a suspending
+data source; writing a marker processor that copes with input suspension is
+not easy (consider what happens if the marker is longer than your available
+input buffer). However, the second method conserves memory since the marker
+data need not be kept around after it's been processed.
+
+For either method, you'd normally set up marker handling after creating a
+decompression object and before calling jpeg_read_header(), because the
+markers of interest will typically be near the head of the file and so will
+be scanned by jpeg_read_header. Once you've established a marker handling
+method, it will be used for the life of that decompression object
+(potentially many datastreams), unless you change it. Marker handling is
+determined separately for COM markers and for each APPn marker code.
+
+
+To save the contents of special markers in memory, call
+ jpeg_save_markers(cinfo, marker_code, length_limit)
+where marker_code is the marker type to save, JPEG_COM or JPEG_APP0+n.
+(To arrange to save all the special marker types, you need to call this
+routine 17 times, for COM and APP0-APP15.) If the incoming marker is longer
+than length_limit data bytes, only length_limit bytes will be saved; this
+parameter allows you to avoid chewing up memory when you only need to see the
+first few bytes of a potentially large marker. If you want to save all the
+data, set length_limit to 0xFFFF; that is enough since marker lengths are only
+16 bits. As a special case, setting length_limit to 0 prevents that marker
+type from being saved at all. (That is the default behavior, in fact.)
+
+After jpeg_read_header() completes, you can examine the special markers by
+following the cinfo->marker_list pointer chain. All the special markers in
+the file appear in this list, in order of their occurrence in the file (but
+omitting any markers of types you didn't ask for). Both the original data
+length and the saved data length are recorded for each list entry; the latter
+will not exceed length_limit for the particular marker type. Note that these
+lengths exclude the marker length word, whereas the stored representation
+within the JPEG file includes it. (Hence the maximum data length is really
+only 65533.)
+
+It is possible that additional special markers appear in the file beyond the
+SOS marker at which jpeg_read_header stops; if so, the marker list will be
+extended during reading of the rest of the file. This is not expected to be
+common, however. If you are short on memory you may want to reset the length
+limit to zero for all marker types after finishing jpeg_read_header, to
+ensure that the max_memory_to_use setting cannot be exceeded due to addition
+of later markers.
+
+The marker list remains stored until you call jpeg_finish_decompress or
+jpeg_abort, at which point the memory is freed and the list is set to empty.
+(jpeg_destroy also releases the storage, of course.)
+
+Note that the library is internally interested in APP0 and APP14 markers;
+if you try to set a small nonzero length limit on these types, the library
+will silently force the length up to the minimum it wants. (But you can set
+a zero length limit to prevent them from being saved at all.) Also, in a
+16-bit environment, the maximum length limit may be constrained to less than
+65533 by malloc() limitations. It is therefore best not to assume that the
+effective length limit is exactly what you set it to be.
+
+
+If you want to supply your own marker-reading routine, you do it by calling
+jpeg_set_marker_processor(). A marker processor routine must have the
+signature
+ boolean jpeg_marker_parser_method (j_decompress_ptr cinfo)
+Although the marker code is not explicitly passed, the routine can find it
+in cinfo->unread_marker. At the time of call, the marker proper has been
+read from the data source module. The processor routine is responsible for
+reading the marker length word and the remaining parameter bytes, if any.
+Return TRUE to indicate success. (FALSE should be returned only if you are
+using a suspending data source and it tells you to suspend. See the standard
+marker processors in jdmarker.c for appropriate coding methods if you need to
+use a suspending data source.)
+
+If you override the default APP0 or APP14 processors, it is up to you to
+recognize JFIF and Adobe markers if you want colorspace recognition to occur
+properly. We recommend copying and extending the default processors if you
+want to do that. (A better idea is to save these marker types for later
+examination by calling jpeg_save_markers(); that method doesn't interfere
+with the library's own processing of these markers.)
+
+jpeg_set_marker_processor() and jpeg_save_markers() are mutually exclusive
+--- if you call one it overrides any previous call to the other, for the
+particular marker type specified.
+
+A simple example of an external COM processor can be found in djpeg.c.
+Also, see jpegtran.c for an example of using jpeg_save_markers.
+
+
+Raw (downsampled) image data
+----------------------------
+
+Some applications need to supply already-downsampled image data to the JPEG
+compressor, or to receive raw downsampled data from the decompressor. The
+library supports this requirement by allowing the application to write or
+read raw data, bypassing the normal preprocessing or postprocessing steps.
+The interface is different from the standard one and is somewhat harder to
+use. If your interest is merely in bypassing color conversion, we recommend
+that you use the standard interface and simply set jpeg_color_space =
+in_color_space (or jpeg_color_space = out_color_space for decompression).
+The mechanism described in this section is necessary only to supply or
+receive downsampled image data, in which not all components have the same
+dimensions.
+
+
+To compress raw data, you must supply the data in the colorspace to be used
+in the JPEG file (please read the earlier section on Special color spaces)
+and downsampled to the sampling factors specified in the JPEG parameters.
+You must supply the data in the format used internally by the JPEG library,
+namely a JSAMPIMAGE array. This is an array of pointers to two-dimensional
+arrays, each of type JSAMPARRAY. Each 2-D array holds the values for one
+color component. This structure is necessary since the components are of
+different sizes. If the image dimensions are not a multiple of the MCU size,
+you must also pad the data correctly (usually, this is done by replicating
+the last column and/or row). The data must be padded to a multiple of a DCT
+block in each component: that is, each downsampled row must contain a
+multiple of 8 valid samples, and there must be a multiple of 8 sample rows
+for each component. (For applications such as conversion of digital TV
+images, the standard image size is usually a multiple of the DCT block size,
+so that no padding need actually be done.)
+
+The procedure for compression of raw data is basically the same as normal
+compression, except that you call jpeg_write_raw_data() in place of
+jpeg_write_scanlines(). Before calling jpeg_start_compress(), you must do
+the following:
+ * Set cinfo->raw_data_in to TRUE. (It is set FALSE by jpeg_set_defaults().)
+ This notifies the library that you will be supplying raw data.
+ * Ensure jpeg_color_space is correct --- an explicit jpeg_set_colorspace()
+ call is a good idea. Note that since color conversion is bypassed,
+ in_color_space is ignored, except that jpeg_set_defaults() uses it to
+ choose the default jpeg_color_space setting.
+ * Ensure the sampling factors, cinfo->comp_info[i].h_samp_factor and
+ cinfo->comp_info[i].v_samp_factor, are correct. Since these indicate the
+ dimensions of the data you are supplying, it's wise to set them
+ explicitly, rather than assuming the library's defaults are what you want.
+
+To pass raw data to the library, call jpeg_write_raw_data() in place of
+jpeg_write_scanlines(). The two routines work similarly except that
+jpeg_write_raw_data takes a JSAMPIMAGE data array rather than JSAMPARRAY.
+The scanlines count passed to and returned from jpeg_write_raw_data is
+measured in terms of the component with the largest v_samp_factor.
+
+jpeg_write_raw_data() processes one MCU row per call, which is to say
+v_samp_factor*DCTSIZE sample rows of each component. The passed num_lines
+value must be at least max_v_samp_factor*DCTSIZE, and the return value will
+be exactly that amount (or possibly some multiple of that amount, in future
+library versions). This is true even on the last call at the bottom of the
+image; don't forget to pad your data as necessary.
+
+The required dimensions of the supplied data can be computed for each
+component as
+ cinfo->comp_info[i].width_in_blocks*DCTSIZE samples per row
+ cinfo->comp_info[i].height_in_blocks*DCTSIZE rows in image
+after jpeg_start_compress() has initialized those fields. If the valid data
+is smaller than this, it must be padded appropriately. For some sampling
+factors and image sizes, additional dummy DCT blocks are inserted to make
+the image a multiple of the MCU dimensions. The library creates such dummy
+blocks itself; it does not read them from your supplied data. Therefore you
+need never pad by more than DCTSIZE samples. An example may help here.
+Assume 2h2v downsampling of YCbCr data, that is
+ cinfo->comp_info[0].h_samp_factor = 2 for Y
+ cinfo->comp_info[0].v_samp_factor = 2
+ cinfo->comp_info[1].h_samp_factor = 1 for Cb
+ cinfo->comp_info[1].v_samp_factor = 1
+ cinfo->comp_info[2].h_samp_factor = 1 for Cr
+ cinfo->comp_info[2].v_samp_factor = 1
+and suppose that the nominal image dimensions (cinfo->image_width and
+cinfo->image_height) are 101x101 pixels. Then jpeg_start_compress() will
+compute downsampled_width = 101 and width_in_blocks = 13 for Y,
+downsampled_width = 51 and width_in_blocks = 7 for Cb and Cr (and the same
+for the height fields). You must pad the Y data to at least 13*8 = 104
+columns and rows, the Cb/Cr data to at least 7*8 = 56 columns and rows. The
+MCU height is max_v_samp_factor = 2 DCT rows so you must pass at least 16
+scanlines on each call to jpeg_write_raw_data(), which is to say 16 actual
+sample rows of Y and 8 each of Cb and Cr. A total of 7 MCU rows are needed,
+so you must pass a total of 7*16 = 112 "scanlines". The last DCT block row
+of Y data is dummy, so it doesn't matter what you pass for it in the data
+arrays, but the scanlines count must total up to 112 so that all of the Cb
+and Cr data gets passed.
+
+Output suspension is supported with raw-data compression: if the data
+destination module suspends, jpeg_write_raw_data() will return 0.
+In this case the same data rows must be passed again on the next call.
+
+
+Decompression with raw data output implies bypassing all postprocessing:
+you cannot ask for rescaling or color quantization, for instance. More
+seriously, you must deal with the color space and sampling factors present in
+the incoming file. If your application only handles, say, 2h1v YCbCr data,
+you must check for and fail on other color spaces or other sampling factors.
+The library will not convert to a different color space for you.
+
+To obtain raw data output, set cinfo->raw_data_out = TRUE before
+jpeg_start_decompress() (it is set FALSE by jpeg_read_header()). Be sure to
+verify that the color space and sampling factors are ones you can handle.
+Then call jpeg_read_raw_data() in place of jpeg_read_scanlines(). The
+decompression process is otherwise the same as usual.
+
+jpeg_read_raw_data() returns one MCU row per call, and thus you must pass a
+buffer of at least max_v_samp_factor*DCTSIZE scanlines (scanline counting is
+the same as for raw-data compression). The buffer you pass must be large
+enough to hold the actual data plus padding to DCT-block boundaries. As with
+compression, any entirely dummy DCT blocks are not processed so you need not
+allocate space for them, but the total scanline count includes them. The
+above example of computing buffer dimensions for raw-data compression is
+equally valid for decompression.
+
+Input suspension is supported with raw-data decompression: if the data source
+module suspends, jpeg_read_raw_data() will return 0. You can also use
+buffered-image mode to read raw data in multiple passes.
+
+
+Really raw data: DCT coefficients
+---------------------------------
+
+It is possible to read or write the contents of a JPEG file as raw DCT
+coefficients. This facility is mainly intended for use in lossless
+transcoding between different JPEG file formats. Other possible applications
+include lossless cropping of a JPEG image, lossless reassembly of a
+multi-strip or multi-tile TIFF/JPEG file into a single JPEG datastream, etc.
+
+To read the contents of a JPEG file as DCT coefficients, open the file and do
+jpeg_read_header() as usual. But instead of calling jpeg_start_decompress()
+and jpeg_read_scanlines(), call jpeg_read_coefficients(). This will read the
+entire image into a set of virtual coefficient-block arrays, one array per
+component. The return value is a pointer to an array of virtual-array
+descriptors. Each virtual array can be accessed directly using the JPEG
+memory manager's access_virt_barray method (see Memory management, below,
+and also read structure.doc's discussion of virtual array handling). Or,
+for simple transcoding to a different JPEG file format, the array list can
+just be handed directly to jpeg_write_coefficients().
+
+Each block in the block arrays contains quantized coefficient values in
+normal array order (not JPEG zigzag order). The block arrays contain only
+DCT blocks containing real data; any entirely-dummy blocks added to fill out
+interleaved MCUs at the right or bottom edges of the image are discarded
+during reading and are not stored in the block arrays. (The size of each
+block array can be determined from the width_in_blocks and height_in_blocks
+fields of the component's comp_info entry.) This is also the data format
+expected by jpeg_write_coefficients().
+
+When you are done using the virtual arrays, call jpeg_finish_decompress()
+to release the array storage and return the decompression object to an idle
+state; or just call jpeg_destroy() if you don't need to reuse the object.
+
+If you use a suspending data source, jpeg_read_coefficients() will return
+NULL if it is forced to suspend; a non-NULL return value indicates successful
+completion. You need not test for a NULL return value when using a
+non-suspending data source.
+
+It is also possible to call jpeg_read_coefficients() to obtain access to the
+decoder's coefficient arrays during a normal decode cycle in buffered-image
+mode. This frammish might be useful for progressively displaying an incoming
+image and then re-encoding it without loss. To do this, decode in buffered-
+image mode as discussed previously, then call jpeg_read_coefficients() after
+the last jpeg_finish_output() call. The arrays will be available for your use
+until you call jpeg_finish_decompress().
+
+
+To write the contents of a JPEG file as DCT coefficients, you must provide
+the DCT coefficients stored in virtual block arrays. You can either pass
+block arrays read from an input JPEG file by jpeg_read_coefficients(), or
+allocate virtual arrays from the JPEG compression object and fill them
+yourself. In either case, jpeg_write_coefficients() is substituted for
+jpeg_start_compress() and jpeg_write_scanlines(). Thus the sequence is
+ * Create compression object
+ * Set all compression parameters as necessary
+ * Request virtual arrays if needed
+ * jpeg_write_coefficients()
+ * jpeg_finish_compress()
+ * Destroy or re-use compression object
+jpeg_write_coefficients() is passed a pointer to an array of virtual block
+array descriptors; the number of arrays is equal to cinfo.num_components.
+
+The virtual arrays need only have been requested, not realized, before
+jpeg_write_coefficients() is called. A side-effect of
+jpeg_write_coefficients() is to realize any virtual arrays that have been
+requested from the compression object's memory manager. Thus, when obtaining
+the virtual arrays from the compression object, you should fill the arrays
+after calling jpeg_write_coefficients(). The data is actually written out
+when you call jpeg_finish_compress(); jpeg_write_coefficients() only writes
+the file header.
+
+When writing raw DCT coefficients, it is crucial that the JPEG quantization
+tables and sampling factors match the way the data was encoded, or the
+resulting file will be invalid. For transcoding from an existing JPEG file,
+we recommend using jpeg_copy_critical_parameters(). This routine initializes
+all the compression parameters to default values (like jpeg_set_defaults()),
+then copies the critical information from a source decompression object.
+The decompression object should have just been used to read the entire
+JPEG input file --- that is, it should be awaiting jpeg_finish_decompress().
+
+jpeg_write_coefficients() marks all tables stored in the compression object
+as needing to be written to the output file (thus, it acts like
+jpeg_start_compress(cinfo, TRUE)). This is for safety's sake, to avoid
+emitting abbreviated JPEG files by accident. If you really want to emit an
+abbreviated JPEG file, call jpeg_suppress_tables(), or set the tables'
+individual sent_table flags, between calling jpeg_write_coefficients() and
+jpeg_finish_compress().
+
+
+Progress monitoring
+-------------------
+
+Some applications may need to regain control from the JPEG library every so
+often. The typical use of this feature is to produce a percent-done bar or
+other progress display. (For a simple example, see cjpeg.c or djpeg.c.)
+Although you do get control back frequently during the data-transferring pass
+(the jpeg_read_scanlines or jpeg_write_scanlines loop), any additional passes
+will occur inside jpeg_finish_compress or jpeg_start_decompress; those
+routines may take a long time to execute, and you don't get control back
+until they are done.
+
+You can define a progress-monitor routine which will be called periodically
+by the library. No guarantees are made about how often this call will occur,
+so we don't recommend you use it for mouse tracking or anything like that.
+At present, a call will occur once per MCU row, scanline, or sample row
+group, whichever unit is convenient for the current processing mode; so the
+wider the image, the longer the time between calls. During the data
+transferring pass, only one call occurs per call of jpeg_read_scanlines or
+jpeg_write_scanlines, so don't pass a large number of scanlines at once if
+you want fine resolution in the progress count. (If you really need to use
+the callback mechanism for time-critical tasks like mouse tracking, you could
+insert additional calls inside some of the library's inner loops.)
+
+To establish a progress-monitor callback, create a struct jpeg_progress_mgr,
+fill in its progress_monitor field with a pointer to your callback routine,
+and set cinfo->progress to point to the struct. The callback will be called
+whenever cinfo->progress is non-NULL. (This pointer is set to NULL by
+jpeg_create_compress or jpeg_create_decompress; the library will not change
+it thereafter. So if you allocate dynamic storage for the progress struct,
+make sure it will live as long as the JPEG object does. Allocating from the
+JPEG memory manager with lifetime JPOOL_PERMANENT will work nicely.) You
+can use the same callback routine for both compression and decompression.
+
+The jpeg_progress_mgr struct contains four fields which are set by the library:
+ long pass_counter; /* work units completed in this pass */
+ long pass_limit; /* total number of work units in this pass */
+ int completed_passes; /* passes completed so far */
+ int total_passes; /* total number of passes expected */
+During any one pass, pass_counter increases from 0 up to (not including)
+pass_limit; the step size is usually but not necessarily 1. The pass_limit
+value may change from one pass to another. The expected total number of
+passes is in total_passes, and the number of passes already completed is in
+completed_passes. Thus the fraction of work completed may be estimated as
+ completed_passes + (pass_counter/pass_limit)
+ --------------------------------------------
+ total_passes
+ignoring the fact that the passes may not be equal amounts of work.
+
+When decompressing, pass_limit can even change within a pass, because it
+depends on the number of scans in the JPEG file, which isn't always known in
+advance. The computed fraction-of-work-done may jump suddenly (if the library
+discovers it has overestimated the number of scans) or even decrease (in the
+opposite case). It is not wise to put great faith in the work estimate.
+
+When using the decompressor's buffered-image mode, the progress monitor work
+estimate is likely to be completely unhelpful, because the library has no way
+to know how many output passes will be demanded of it. Currently, the library
+sets total_passes based on the assumption that there will be one more output
+pass if the input file end hasn't yet been read (jpeg_input_complete() isn't
+TRUE), but no more output passes if the file end has been reached when the
+output pass is started. This means that total_passes will rise as additional
+output passes are requested. If you have a way of determining the input file
+size, estimating progress based on the fraction of the file that's been read
+will probably be more useful than using the library's value.
+
+
+Memory management
+-----------------
+
+This section covers some key facts about the JPEG library's built-in memory
+manager. For more info, please read structure.doc's section about the memory
+manager, and consult the source code if necessary.
+
+All memory and temporary file allocation within the library is done via the
+memory manager. If necessary, you can replace the "back end" of the memory
+manager to control allocation yourself (for example, if you don't want the
+library to use malloc() and free() for some reason).
+
+Some data is allocated "permanently" and will not be freed until the JPEG
+object is destroyed. Most data is allocated "per image" and is freed by
+jpeg_finish_compress, jpeg_finish_decompress, or jpeg_abort. You can call the
+memory manager yourself to allocate structures that will automatically be
+freed at these times. Typical code for this is
+ ptr = (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, size);
+Use JPOOL_PERMANENT to get storage that lasts as long as the JPEG object.
+Use alloc_large instead of alloc_small for anything bigger than a few Kbytes.
+There are also alloc_sarray and alloc_barray routines that automatically
+build 2-D sample or block arrays.
+
+The library's minimum space requirements to process an image depend on the
+image's width, but not on its height, because the library ordinarily works
+with "strip" buffers that are as wide as the image but just a few rows high.
+Some operating modes (eg, two-pass color quantization) require full-image
+buffers. Such buffers are treated as "virtual arrays": only the current strip
+need be in memory, and the rest can be swapped out to a temporary file.
+
+If you use the simplest memory manager back end (jmemnobs.c), then no
+temporary files are used; virtual arrays are simply malloc()'d. Images bigger
+than memory can be processed only if your system supports virtual memory.
+The other memory manager back ends support temporary files of various flavors
+and thus work in machines without virtual memory. They may also be useful on
+Unix machines if you need to process images that exceed available swap space.
+
+When using temporary files, the library will make the in-memory buffers for
+its virtual arrays just big enough to stay within a "maximum memory" setting.
+Your application can set this limit by setting cinfo->mem->max_memory_to_use
+after creating the JPEG object. (Of course, there is still a minimum size for
+the buffers, so the max-memory setting is effective only if it is bigger than
+the minimum space needed.) If you allocate any large structures yourself, you
+must allocate them before jpeg_start_compress() or jpeg_start_decompress() in
+order to have them counted against the max memory limit. Also keep in mind
+that space allocated with alloc_small() is ignored, on the assumption that
+it's too small to be worth worrying about; so a reasonable safety margin
+should be left when setting max_memory_to_use.
+
+If you use the jmemname.c or jmemdos.c memory manager back end, it is
+important to clean up the JPEG object properly to ensure that the temporary
+files get deleted. (This is especially crucial with jmemdos.c, where the
+"temporary files" may be extended-memory segments; if they are not freed,
+DOS will require a reboot to recover the memory.) Thus, with these memory
+managers, it's a good idea to provide a signal handler that will trap any
+early exit from your program. The handler should call either jpeg_abort()
+or jpeg_destroy() for any active JPEG objects. A handler is not needed with
+jmemnobs.c, and shouldn't be necessary with jmemansi.c or jmemmac.c either,
+since the C library is supposed to take care of deleting files made with
+tmpfile().
+
+
+Memory usage
+------------
+
+Working memory requirements while performing compression or decompression
+depend on image dimensions, image characteristics (such as colorspace and
+JPEG process), and operating mode (application-selected options).
+
+As of v6b, the decompressor requires:
+ 1. About 24K in more-or-less-fixed-size data. This varies a bit depending
+ on operating mode and image characteristics (particularly color vs.
+ grayscale), but it doesn't depend on image dimensions.
+ 2. Strip buffers (of size proportional to the image width) for IDCT and
+ upsampling results. The worst case for commonly used sampling factors
+ is about 34 bytes * width in pixels for a color image. A grayscale image
+ only needs about 8 bytes per pixel column.
+ 3. A full-image DCT coefficient buffer is needed to decode a multi-scan JPEG
+ file (including progressive JPEGs), or whenever you select buffered-image
+ mode. This takes 2 bytes/coefficient. At typical 2x2 sampling, that's
+ 3 bytes per pixel for a color image. Worst case (1x1 sampling) requires
+ 6 bytes/pixel. For grayscale, figure 2 bytes/pixel.
+ 4. To perform 2-pass color quantization, the decompressor also needs a
+ 128K color lookup table and a full-image pixel buffer (3 bytes/pixel).
+This does not count any memory allocated by the application, such as a
+buffer to hold the final output image.
+
+The above figures are valid for 8-bit JPEG data precision and a machine with
+32-bit ints. For 12-bit JPEG data, double the size of the strip buffers and
+quantization pixel buffer. The "fixed-size" data will be somewhat smaller
+with 16-bit ints, larger with 64-bit ints. Also, CMYK or other unusual
+color spaces will require different amounts of space.
+
+The full-image coefficient and pixel buffers, if needed at all, do not
+have to be fully RAM resident; you can have the library use temporary
+files instead when the total memory usage would exceed a limit you set.
+(But if your OS supports virtual memory, it's probably better to just use
+jmemnobs and let the OS do the swapping.)
+
+The compressor's memory requirements are similar, except that it has no need
+for color quantization. Also, it needs a full-image DCT coefficient buffer
+if Huffman-table optimization is asked for, even if progressive mode is not
+requested.
+
+If you need more detailed information about memory usage in a particular
+situation, you can enable the MEM_STATS code in jmemmgr.c.
+
+
+Library compile-time options
+----------------------------
+
+A number of compile-time options are available by modifying jmorecfg.h.
+
+The JPEG standard provides for both the baseline 8-bit DCT process and
+a 12-bit DCT process. The IJG code supports 12-bit lossy JPEG if you define
+BITS_IN_JSAMPLE as 12 rather than 8. Note that this causes JSAMPLE to be
+larger than a char, so it affects the surrounding application's image data.
+The sample applications cjpeg and djpeg can support 12-bit mode only for PPM
+and GIF file formats; you must disable the other file formats to compile a
+12-bit cjpeg or djpeg. (install.doc has more information about that.)
+At present, a 12-bit library can handle *only* 12-bit images, not both
+precisions. (If you need to include both 8- and 12-bit libraries in a single
+application, you could probably do it by defining NEED_SHORT_EXTERNAL_NAMES
+for just one of the copies. You'd have to access the 8-bit and 12-bit copies
+from separate application source files. This is untested ... if you try it,
+we'd like to hear whether it works!)
+
+Note that a 12-bit library always compresses in Huffman optimization mode,
+in order to generate valid Huffman tables. This is necessary because our
+default Huffman tables only cover 8-bit data. If you need to output 12-bit
+files in one pass, you'll have to supply suitable default Huffman tables.
+You may also want to supply your own DCT quantization tables; the existing
+quality-scaling code has been developed for 8-bit use, and probably doesn't
+generate especially good tables for 12-bit.
+
+The maximum number of components (color channels) in the image is determined
+by MAX_COMPONENTS. The JPEG standard allows up to 255 components, but we
+expect that few applications will need more than four or so.
+
+On machines with unusual data type sizes, you may be able to improve
+performance or reduce memory space by tweaking the various typedefs in
+jmorecfg.h. In particular, on some RISC CPUs, access to arrays of "short"s
+is quite slow; consider trading memory for speed by making JCOEF, INT16, and
+UINT16 be "int" or "unsigned int". UINT8 is also a candidate to become int.
+You probably don't want to make JSAMPLE be int unless you have lots of memory
+to burn.
+
+You can reduce the size of the library by compiling out various optional
+functions. To do this, undefine xxx_SUPPORTED symbols as necessary.
+
+You can also save a few K by not having text error messages in the library;
+the standard error message table occupies about 5Kb. This is particularly
+reasonable for embedded applications where there's no good way to display
+a message anyway. To do this, remove the creation of the message table
+(jpeg_std_message_table[]) from jerror.c, and alter format_message to do
+something reasonable without it. You could output the numeric value of the
+message code number, for example. If you do this, you can also save a couple
+more K by modifying the TRACEMSn() macros in jerror.h to expand to nothing;
+you don't need trace capability anyway, right?
+
+
+Portability considerations
+--------------------------
+
+The JPEG library has been written to be extremely portable; the sample
+applications cjpeg and djpeg are slightly less so. This section summarizes
+the design goals in this area. (If you encounter any bugs that cause the
+library to be less portable than is claimed here, we'd appreciate hearing
+about them.)
+
+The code works fine on ANSI C, C++, and pre-ANSI C compilers, using any of
+the popular system include file setups, and some not-so-popular ones too.
+See install.doc for configuration procedures.
+
+The code is not dependent on the exact sizes of the C data types. As
+distributed, we make the assumptions that
+ char is at least 8 bits wide
+ short is at least 16 bits wide
+ int is at least 16 bits wide
+ long is at least 32 bits wide
+(These are the minimum requirements of the ANSI C standard.) Wider types will
+work fine, although memory may be used inefficiently if char is much larger
+than 8 bits or short is much bigger than 16 bits. The code should work
+equally well with 16- or 32-bit ints.
+
+In a system where these assumptions are not met, you may be able to make the
+code work by modifying the typedefs in jmorecfg.h. However, you will probably
+have difficulty if int is less than 16 bits wide, since references to plain
+int abound in the code.
+
+char can be either signed or unsigned, although the code runs faster if an
+unsigned char type is available. If char is wider than 8 bits, you will need
+to redefine JOCTET and/or provide custom data source/destination managers so
+that JOCTET represents exactly 8 bits of data on external storage.
+
+The JPEG library proper does not assume ASCII representation of characters.
+But some of the image file I/O modules in cjpeg/djpeg do have ASCII
+dependencies in file-header manipulation; so does cjpeg's select_file_type()
+routine.
+
+The JPEG library does not rely heavily on the C library. In particular, C
+stdio is used only by the data source/destination modules and the error
+handler, all of which are application-replaceable. (cjpeg/djpeg are more
+heavily dependent on stdio.) malloc and free are called only from the memory
+manager "back end" module, so you can use a different memory allocator by
+replacing that one file.
+
+The code generally assumes that C names must be unique in the first 15
+characters. However, global function names can be made unique in the
+first 6 characters by defining NEED_SHORT_EXTERNAL_NAMES.
+
+More info about porting the code may be gleaned by reading jconfig.doc,
+jmorecfg.h, and jinclude.h.
+
+
+Notes for MS-DOS implementors
+-----------------------------
+
+The IJG code is designed to work efficiently in 80x86 "small" or "medium"
+memory models (i.e., data pointers are 16 bits unless explicitly declared
+"far"; code pointers can be either size). You may be able to use small
+model to compile cjpeg or djpeg by itself, but you will probably have to use
+medium model for any larger application. This won't make much difference in
+performance. You *will* take a noticeable performance hit if you use a
+large-data memory model (perhaps 10%-25%), and you should avoid "huge" model
+if at all possible.
+
+The JPEG library typically needs 2Kb-3Kb of stack space. It will also
+malloc about 20K-30K of near heap space while executing (and lots of far
+heap, but that doesn't count in this calculation). This figure will vary
+depending on selected operating mode, and to a lesser extent on image size.
+There is also about 5Kb-6Kb of constant data which will be allocated in the
+near data segment (about 4Kb of this is the error message table).
+Thus you have perhaps 20K available for other modules' static data and near
+heap space before you need to go to a larger memory model. The C library's
+static data will account for several K of this, but that still leaves a good
+deal for your needs. (If you are tight on space, you could reduce the sizes
+of the I/O buffers allocated by jdatasrc.c and jdatadst.c, say from 4K to
+1K. Another possibility is to move the error message table to far memory;
+this should be doable with only localized hacking on jerror.c.)
+
+About 2K of the near heap space is "permanent" memory that will not be
+released until you destroy the JPEG object. This is only an issue if you
+save a JPEG object between compression or decompression operations.
+
+Far data space may also be a tight resource when you are dealing with large
+images. The most memory-intensive case is decompression with two-pass color
+quantization, or single-pass quantization to an externally supplied color
+map. This requires a 128Kb color lookup table plus strip buffers amounting
+to about 40 bytes per column for typical sampling ratios (eg, about 25600
+bytes for a 640-pixel-wide image). You may not be able to process wide
+images if you have large data structures of your own.
+
+Of course, all of these concerns vanish if you use a 32-bit flat-memory-model
+compiler, such as DJGPP or Watcom C. We highly recommend flat model if you
+can use it; the JPEG library is significantly faster in flat model.
--- /dev/null
+#ifndef gdcm_jpeg12_mangle_h
+#define gdcm_jpeg12_mangle_h
+
+/*
+
+This header file mangles all symbols exported from the jpeg library.
+It is included in all files while building the jpeg library. Due to
+namespace pollution, no jpeg headers should be included in .h files in
+GDCM. This also allows us to generate two jpeg library (8bits and 12bits).
+
+The following command was used to obtain the symbol list:
+
+nm libgdcmjpeg12.a | grep " [R|T] " | colrm 1 11 | sort
+
+(actually copy/paste from jpeg8bits)
+*/
+
+
+
+#define jcopy_block_row gdcm_jpeg12_jcopy_block_row
+#define jcopy_sample_rows gdcm_jpeg12_jcopy_sample_rows
+#define jdiv_round_up gdcm_jpeg12_jdiv_round_up
+#define jinit_1pass_quantizer gdcm_jpeg12_jinit_1pass_quantizer
+#define jinit_2pass_quantizer gdcm_jpeg12_jinit_2pass_quantizer
+#define jinit_arith_decoder gdcm_jpeg12_jinit_arith_decoder
+#define jinit_arith_encoder gdcm_jpeg12_jinit_arith_encoder
+#define jinit_c_codec gdcm_jpeg12_jinit_c_codec
+#define jinit_c_coef_controller gdcm_jpeg12_jinit_c_coef_controller
+#define jinit_c_diff_controller gdcm_jpeg12_jinit_c_diff_controller
+#define jinit_c_main_controller gdcm_jpeg12_jinit_c_main_controller
+#define jinit_c_master_control gdcm_jpeg12_jinit_c_master_control
+#define jinit_c_prep_controller gdcm_jpeg12_jinit_c_prep_controller
+#define jinit_c_scaler gdcm_jpeg12_jinit_c_scaler
+#define jinit_color_converter gdcm_jpeg12_jinit_color_converter
+#define jinit_color_deconverter gdcm_jpeg12_jinit_color_deconverter
+#define jinit_compress_master gdcm_jpeg12_jinit_compress_master
+#define jinit_d_codec gdcm_jpeg12_jinit_d_codec
+#define jinit_d_coef_controller gdcm_jpeg12_jinit_d_coef_controller
+#define jinit_d_diff_controller gdcm_jpeg12_jinit_d_diff_controller
+#define jinit_d_main_controller gdcm_jpeg12_jinit_d_main_controller
+#define jinit_d_post_controller gdcm_jpeg12_jinit_d_post_controller
+#define jinit_d_scaler gdcm_jpeg12_jinit_d_scaler
+#define jinit_differencer gdcm_jpeg12_jinit_differencer
+#define jinit_downsampler gdcm_jpeg12_jinit_downsampler
+#define jinit_forward_dct gdcm_jpeg12_jinit_forward_dct
+#define jinit_input_controller gdcm_jpeg12_jinit_input_controller
+#define jinit_inverse_dct gdcm_jpeg12_jinit_inverse_dct
+#define jinit_lhuff_decoder gdcm_jpeg12_jinit_lhuff_decoder
+#define jinit_lhuff_encoder gdcm_jpeg12_jinit_lhuff_encoder
+#define jinit_lossless_c_codec gdcm_jpeg12_jinit_lossless_c_codec
+#define jinit_lossless_d_codec gdcm_jpeg12_jinit_lossless_d_codec
+#define jinit_lossy_c_codec gdcm_jpeg12_jinit_lossy_c_codec
+#define jinit_lossy_d_codec gdcm_jpeg12_jinit_lossy_d_codec
+#define jinit_marker_reader gdcm_jpeg12_jinit_marker_reader
+#define jinit_marker_writer gdcm_jpeg12_jinit_marker_writer
+#define jinit_master_decompress gdcm_jpeg12_jinit_master_decompress
+#define jinit_memory_mgr gdcm_jpeg12_jinit_memory_mgr
+#define jinit_merged_upsampler gdcm_jpeg12_jinit_merged_upsampler
+#define jinit_phuff_decoder gdcm_jpeg12_jinit_phuff_decoder
+#define jinit_phuff_encoder gdcm_jpeg12_jinit_phuff_encoder
+#define jinit_shuff_decoder gdcm_jpeg12_jinit_shuff_decoder
+#define jinit_shuff_encoder gdcm_jpeg12_jinit_shuff_encoder
+#define jinit_undifferencer gdcm_jpeg12_jinit_undifferencer
+#define jinit_upsampler gdcm_jpeg12_jinit_upsampler
+#define jpeg_CreateCompress gdcm_jpeg12_jpeg_CreateCompress
+#define jpeg_CreateDecompress gdcm_jpeg12_jpeg_CreateDecompress
+#define jpeg_abort gdcm_jpeg12_jpeg_abort
+#define jpeg_abort_compress gdcm_jpeg12_jpeg_abort_compress
+#define jpeg_abort_decompress gdcm_jpeg12_jpeg_abort_decompress
+#define jpeg_add_quant_table gdcm_jpeg12_jpeg_add_quant_table
+#define jpeg_alloc_huff_table gdcm_jpeg12_jpeg_alloc_huff_table
+#define jpeg_alloc_quant_table gdcm_jpeg12_jpeg_alloc_quant_table
+#define jpeg_calc_output_dimensions gdcm_jpeg12_jpeg_calc_output_dimensions
+#define jpeg_consume_input gdcm_jpeg12_jpeg_consume_input
+#define jpeg_copy_critical_parameters gdcm_jpeg12_jpeg_copy_critical_parameters
+#define jpeg_default_colorspace gdcm_jpeg12_jpeg_default_colorspace
+#define jpeg_destroy gdcm_jpeg12_jpeg_destroy
+#define jpeg_destroy_compress gdcm_jpeg12_jpeg_destroy_compress
+#define jpeg_destroy_decompress gdcm_jpeg12_jpeg_destroy_decompress
+#define jpeg_fdct_float gdcm_jpeg12_jpeg_fdct_float
+#define jpeg_fdct_ifast gdcm_jpeg12_jpeg_fdct_ifast
+#define jpeg_fdct_islow gdcm_jpeg12_jpeg_fdct_islow
+#define jpeg_fill_bit_buffer gdcm_jpeg12_jpeg_fill_bit_buffer
+#define jpeg_finish_compress gdcm_jpeg12_jpeg_finish_compress
+#define jpeg_finish_decompress gdcm_jpeg12_jpeg_finish_decompress
+#define jpeg_finish_output gdcm_jpeg12_jpeg_finish_output
+#define jpeg_free_large gdcm_jpeg12_jpeg_free_large
+#define jpeg_free_small gdcm_jpeg12_jpeg_free_small
+#define jpeg_gen_optimal_table gdcm_jpeg12_jpeg_gen_optimal_table
+#define jpeg_get_large gdcm_jpeg12_jpeg_get_large
+#define jpeg_get_small gdcm_jpeg12_jpeg_get_small
+#define jpeg_has_multiple_scans gdcm_jpeg12_jpeg_has_multiple_scans
+#define jpeg_huff_decode gdcm_jpeg12_jpeg_huff_decode
+#define jpeg_idct_1x1 gdcm_jpeg12_jpeg_idct_1x1
+#define jpeg_idct_2x2 gdcm_jpeg12_jpeg_idct_2x2
+#define jpeg_idct_4x4 gdcm_jpeg12_jpeg_idct_4x4
+#define jpeg_idct_float gdcm_jpeg12_jpeg_idct_float
+#define jpeg_idct_ifast gdcm_jpeg12_jpeg_idct_ifast
+#define jpeg_idct_islow gdcm_jpeg12_jpeg_idct_islow
+#define jpeg_input_complete gdcm_jpeg12_jpeg_input_complete
+#define jpeg_make_c_derived_tbl gdcm_jpeg12_jpeg_make_c_derived_tbl
+#define jpeg_make_d_derived_tbl gdcm_jpeg12_jpeg_make_d_derived_tbl
+#define jpeg_mem_available gdcm_jpeg12_jpeg_mem_available
+#define jpeg_mem_init gdcm_jpeg12_jpeg_mem_init
+#define jpeg_mem_term gdcm_jpeg12_jpeg_mem_term
+#define jpeg_natural_order gdcm_jpeg12_jpeg_natural_order
+#define jpeg_new_colormap gdcm_jpeg12_jpeg_new_colormap
+#define jpeg_open_backing_store gdcm_jpeg12_jpeg_open_backing_store
+#define jpeg_quality_scaling gdcm_jpeg12_jpeg_quality_scaling
+#define jpeg_read_coefficients gdcm_jpeg12_jpeg_read_coefficients
+#define jpeg_read_header gdcm_jpeg12_jpeg_read_header
+#define jpeg_read_raw_data gdcm_jpeg12_jpeg_read_raw_data
+#define jpeg_read_scanlines gdcm_jpeg12_jpeg_read_scanlines
+#define jpeg_resync_to_restart gdcm_jpeg12_jpeg_resync_to_restart
+#define jpeg_save_markers gdcm_jpeg12_jpeg_save_markers
+#define jpeg_set_colorspace gdcm_jpeg12_jpeg_set_colorspace
+#define jpeg_set_defaults gdcm_jpeg12_jpeg_set_defaults
+#define jpeg_set_linear_quality gdcm_jpeg12_jpeg_set_linear_quality
+#define jpeg_set_marker_processor gdcm_jpeg12_jpeg_set_marker_processor
+#define jpeg_set_quality gdcm_jpeg12_jpeg_set_quality
+#define jpeg_simple_lossless gdcm_jpeg12_jpeg_simple_lossless
+#define jpeg_simple_progression gdcm_jpeg12_jpeg_simple_progression
+#define jpeg_start_compress gdcm_jpeg12_jpeg_start_compress
+#define jpeg_start_decompress gdcm_jpeg12_jpeg_start_decompress
+#define jpeg_start_output gdcm_jpeg12_jpeg_start_output
+#define jpeg_std_error gdcm_jpeg12_jpeg_std_error
+#define jpeg_std_message_table gdcm_jpeg12_jpeg_std_message_table
+#define jpeg_stdio_dest gdcm_jpeg12_jpeg_stdio_dest
+#define jpeg_stdio_src gdcm_jpeg12_jpeg_stdio_src
+#define jpeg_suppress_tables gdcm_jpeg12_jpeg_suppress_tables
+#define jpeg_write_coefficients gdcm_jpeg12_jpeg_write_coefficients
+#define jpeg_write_m_byte gdcm_jpeg12_jpeg_write_m_byte
+#define jpeg_write_m_header gdcm_jpeg12_jpeg_write_m_header
+#define jpeg_write_marker gdcm_jpeg12_jpeg_write_marker
+#define jpeg_write_raw_data gdcm_jpeg12_jpeg_write_raw_data
+#define jpeg_write_scanlines gdcm_jpeg12_jpeg_write_scanlines
+#define jpeg_write_tables gdcm_jpeg12_jpeg_write_tables
+#define jround_up gdcm_jpeg12_jround_up
+#define jzero_far gdcm_jpeg12_jzero_far
+
+#endif
--- /dev/null
+#ifndef gdcm_jpeg16_mangle_h
+#define gdcm_jpeg16_mangle_h
+
+/*
+
+This header file mangles all symbols exported from the jpeg library.
+It is included in all files while building the jpeg library. Due to
+namespace pollution, no jpeg headers should be included in .h files in
+GDCM. This also allows us to generate three jpeg library (8, 12 and 16bits).
+
+The following command was used to obtain the symbol list:
+
+nm libgdcmjpeg16.a | grep " [R|T] " | colrm 1 11 | sort
+
+(actually copy/paste from jpeg8bits)
+*/
+
+
+
+#define jcopy_block_row gdcm_jpeg16_jcopy_block_row
+#define jcopy_sample_rows gdcm_jpeg16_jcopy_sample_rows
+#define jdiv_round_up gdcm_jpeg16_jdiv_round_up
+#define jinit_1pass_quantizer gdcm_jpeg16_jinit_1pass_quantizer
+#define jinit_2pass_quantizer gdcm_jpeg16_jinit_2pass_quantizer
+#define jinit_arith_decoder gdcm_jpeg16_jinit_arith_decoder
+#define jinit_arith_encoder gdcm_jpeg16_jinit_arith_encoder
+#define jinit_c_codec gdcm_jpeg16_jinit_c_codec
+#define jinit_c_coef_controller gdcm_jpeg16_jinit_c_coef_controller
+#define jinit_c_diff_controller gdcm_jpeg16_jinit_c_diff_controller
+#define jinit_c_main_controller gdcm_jpeg16_jinit_c_main_controller
+#define jinit_c_master_control gdcm_jpeg16_jinit_c_master_control
+#define jinit_c_prep_controller gdcm_jpeg16_jinit_c_prep_controller
+#define jinit_c_scaler gdcm_jpeg16_jinit_c_scaler
+#define jinit_color_converter gdcm_jpeg16_jinit_color_converter
+#define jinit_color_deconverter gdcm_jpeg16_jinit_color_deconverter
+#define jinit_compress_master gdcm_jpeg16_jinit_compress_master
+#define jinit_d_codec gdcm_jpeg16_jinit_d_codec
+#define jinit_d_coef_controller gdcm_jpeg16_jinit_d_coef_controller
+#define jinit_d_diff_controller gdcm_jpeg16_jinit_d_diff_controller
+#define jinit_d_main_controller gdcm_jpeg16_jinit_d_main_controller
+#define jinit_d_post_controller gdcm_jpeg16_jinit_d_post_controller
+#define jinit_d_scaler gdcm_jpeg16_jinit_d_scaler
+#define jinit_differencer gdcm_jpeg16_jinit_differencer
+#define jinit_downsampler gdcm_jpeg16_jinit_downsampler
+#define jinit_forward_dct gdcm_jpeg16_jinit_forward_dct
+#define jinit_input_controller gdcm_jpeg16_jinit_input_controller
+#define jinit_inverse_dct gdcm_jpeg16_jinit_inverse_dct
+#define jinit_lhuff_decoder gdcm_jpeg16_jinit_lhuff_decoder
+#define jinit_lhuff_encoder gdcm_jpeg16_jinit_lhuff_encoder
+#define jinit_lossless_c_codec gdcm_jpeg16_jinit_lossless_c_codec
+#define jinit_lossless_d_codec gdcm_jpeg16_jinit_lossless_d_codec
+#define jinit_lossy_c_codec gdcm_jpeg16_jinit_lossy_c_codec
+#define jinit_lossy_d_codec gdcm_jpeg16_jinit_lossy_d_codec
+#define jinit_marker_reader gdcm_jpeg16_jinit_marker_reader
+#define jinit_marker_writer gdcm_jpeg16_jinit_marker_writer
+#define jinit_master_decompress gdcm_jpeg16_jinit_master_decompress
+#define jinit_memory_mgr gdcm_jpeg16_jinit_memory_mgr
+#define jinit_merged_upsampler gdcm_jpeg16_jinit_merged_upsampler
+#define jinit_phuff_decoder gdcm_jpeg16_jinit_phuff_decoder
+#define jinit_phuff_encoder gdcm_jpeg16_jinit_phuff_encoder
+#define jinit_shuff_decoder gdcm_jpeg16_jinit_shuff_decoder
+#define jinit_shuff_encoder gdcm_jpeg16_jinit_shuff_encoder
+#define jinit_undifferencer gdcm_jpeg16_jinit_undifferencer
+#define jinit_upsampler gdcm_jpeg16_jinit_upsampler
+#define jpeg_CreateCompress gdcm_jpeg16_jpeg_CreateCompress
+#define jpeg_CreateDecompress gdcm_jpeg16_jpeg_CreateDecompress
+#define jpeg_abort gdcm_jpeg16_jpeg_abort
+#define jpeg_abort_compress gdcm_jpeg16_jpeg_abort_compress
+#define jpeg_abort_decompress gdcm_jpeg16_jpeg_abort_decompress
+#define jpeg_add_quant_table gdcm_jpeg16_jpeg_add_quant_table
+#define jpeg_alloc_huff_table gdcm_jpeg16_jpeg_alloc_huff_table
+#define jpeg_alloc_quant_table gdcm_jpeg16_jpeg_alloc_quant_table
+#define jpeg_calc_output_dimensions gdcm_jpeg16_jpeg_calc_output_dimensions
+#define jpeg_consume_input gdcm_jpeg16_jpeg_consume_input
+#define jpeg_copy_critical_parameters gdcm_jpeg16_jpeg_copy_critical_parameters
+#define jpeg_default_colorspace gdcm_jpeg16_jpeg_default_colorspace
+#define jpeg_destroy gdcm_jpeg16_jpeg_destroy
+#define jpeg_destroy_compress gdcm_jpeg16_jpeg_destroy_compress
+#define jpeg_destroy_decompress gdcm_jpeg16_jpeg_destroy_decompress
+#define jpeg_fdct_float gdcm_jpeg16_jpeg_fdct_float
+#define jpeg_fdct_ifast gdcm_jpeg16_jpeg_fdct_ifast
+#define jpeg_fdct_islow gdcm_jpeg16_jpeg_fdct_islow
+#define jpeg_fill_bit_buffer gdcm_jpeg16_jpeg_fill_bit_buffer
+#define jpeg_finish_compress gdcm_jpeg16_jpeg_finish_compress
+#define jpeg_finish_decompress gdcm_jpeg16_jpeg_finish_decompress
+#define jpeg_finish_output gdcm_jpeg16_jpeg_finish_output
+#define jpeg_free_large gdcm_jpeg16_jpeg_free_large
+#define jpeg_free_small gdcm_jpeg16_jpeg_free_small
+#define jpeg_gen_optimal_table gdcm_jpeg16_jpeg_gen_optimal_table
+#define jpeg_get_large gdcm_jpeg16_jpeg_get_large
+#define jpeg_get_small gdcm_jpeg16_jpeg_get_small
+#define jpeg_has_multiple_scans gdcm_jpeg16_jpeg_has_multiple_scans
+#define jpeg_huff_decode gdcm_jpeg16_jpeg_huff_decode
+#define jpeg_idct_1x1 gdcm_jpeg16_jpeg_idct_1x1
+#define jpeg_idct_2x2 gdcm_jpeg16_jpeg_idct_2x2
+#define jpeg_idct_4x4 gdcm_jpeg16_jpeg_idct_4x4
+#define jpeg_idct_float gdcm_jpeg16_jpeg_idct_float
+#define jpeg_idct_ifast gdcm_jpeg16_jpeg_idct_ifast
+#define jpeg_idct_islow gdcm_jpeg16_jpeg_idct_islow
+#define jpeg_input_complete gdcm_jpeg16_jpeg_input_complete
+#define jpeg_make_c_derived_tbl gdcm_jpeg16_jpeg_make_c_derived_tbl
+#define jpeg_make_d_derived_tbl gdcm_jpeg16_jpeg_make_d_derived_tbl
+#define jpeg_mem_available gdcm_jpeg16_jpeg_mem_available
+#define jpeg_mem_init gdcm_jpeg16_jpeg_mem_init
+#define jpeg_mem_term gdcm_jpeg16_jpeg_mem_term
+#define jpeg_natural_order gdcm_jpeg16_jpeg_natural_order
+#define jpeg_new_colormap gdcm_jpeg16_jpeg_new_colormap
+#define jpeg_open_backing_store gdcm_jpeg16_jpeg_open_backing_store
+#define jpeg_quality_scaling gdcm_jpeg16_jpeg_quality_scaling
+#define jpeg_read_coefficients gdcm_jpeg16_jpeg_read_coefficients
+#define jpeg_read_header gdcm_jpeg16_jpeg_read_header
+#define jpeg_read_raw_data gdcm_jpeg16_jpeg_read_raw_data
+#define jpeg_read_scanlines gdcm_jpeg16_jpeg_read_scanlines
+#define jpeg_resync_to_restart gdcm_jpeg16_jpeg_resync_to_restart
+#define jpeg_save_markers gdcm_jpeg16_jpeg_save_markers
+#define jpeg_set_colorspace gdcm_jpeg16_jpeg_set_colorspace
+#define jpeg_set_defaults gdcm_jpeg16_jpeg_set_defaults
+#define jpeg_set_linear_quality gdcm_jpeg16_jpeg_set_linear_quality
+#define jpeg_set_marker_processor gdcm_jpeg16_jpeg_set_marker_processor
+#define jpeg_set_quality gdcm_jpeg16_jpeg_set_quality
+#define jpeg_simple_lossless gdcm_jpeg16_jpeg_simple_lossless
+#define jpeg_simple_progression gdcm_jpeg16_jpeg_simple_progression
+#define jpeg_start_compress gdcm_jpeg16_jpeg_start_compress
+#define jpeg_start_decompress gdcm_jpeg16_jpeg_start_decompress
+#define jpeg_start_output gdcm_jpeg16_jpeg_start_output
+#define jpeg_std_error gdcm_jpeg16_jpeg_std_error
+#define jpeg_std_message_table gdcm_jpeg16_jpeg_std_message_table
+#define jpeg_stdio_dest gdcm_jpeg16_jpeg_stdio_dest
+#define jpeg_stdio_src gdcm_jpeg16_jpeg_stdio_src
+#define jpeg_suppress_tables gdcm_jpeg16_jpeg_suppress_tables
+#define jpeg_write_coefficients gdcm_jpeg16_jpeg_write_coefficients
+#define jpeg_write_m_byte gdcm_jpeg16_jpeg_write_m_byte
+#define jpeg_write_m_header gdcm_jpeg16_jpeg_write_m_header
+#define jpeg_write_marker gdcm_jpeg16_jpeg_write_marker
+#define jpeg_write_raw_data gdcm_jpeg16_jpeg_write_raw_data
+#define jpeg_write_scanlines gdcm_jpeg16_jpeg_write_scanlines
+#define jpeg_write_tables gdcm_jpeg16_jpeg_write_tables
+#define jround_up gdcm_jpeg16_jround_up
+#define jzero_far gdcm_jpeg16_jzero_far
+
+#endif
--- /dev/null
+#ifndef gdcm_jpeg8_mangle_h
+#define gdcm_jpeg8_mangle_h
+
+/*
+
+This header file mangles all symbols exported from the jpeg library.
+It is included in all files while building the jpeg library. Due to
+namespace pollution, no jpeg headers should be included in .h files in
+GDCM. This also allows us to generate two jpeg library (8bits and 12bits).
+
+The following command was used to obtain the symbol list:
+
+nm libgdcmjpeg8.a | grep " [R|T] " | colrm 1 11 | sort
+*/
+
+
+#define jcopy_block_row gdcm_jpeg8_jcopy_block_row
+#define jcopy_sample_rows gdcm_jpeg8_jcopy_sample_rows
+#define jdiv_round_up gdcm_jpeg8_jdiv_round_up
+#define jinit_1pass_quantizer gdcm_jpeg8_jinit_1pass_quantizer
+#define jinit_2pass_quantizer gdcm_jpeg8_jinit_2pass_quantizer
+#define jinit_arith_decoder gdcm_jpeg8_jinit_arith_decoder
+#define jinit_arith_encoder gdcm_jpeg8_jinit_arith_encoder
+#define jinit_c_codec gdcm_jpeg8_jinit_c_codec
+#define jinit_c_coef_controller gdcm_jpeg8_jinit_c_coef_controller
+#define jinit_c_diff_controller gdcm_jpeg8_jinit_c_diff_controller
+#define jinit_c_main_controller gdcm_jpeg8_jinit_c_main_controller
+#define jinit_c_master_control gdcm_jpeg8_jinit_c_master_control
+#define jinit_c_prep_controller gdcm_jpeg8_jinit_c_prep_controller
+#define jinit_c_scaler gdcm_jpeg8_jinit_c_scaler
+#define jinit_color_converter gdcm_jpeg8_jinit_color_converter
+#define jinit_color_deconverter gdcm_jpeg8_jinit_color_deconverter
+#define jinit_compress_master gdcm_jpeg8_jinit_compress_master
+#define jinit_d_codec gdcm_jpeg8_jinit_d_codec
+#define jinit_d_coef_controller gdcm_jpeg8_jinit_d_coef_controller
+#define jinit_d_diff_controller gdcm_jpeg8_jinit_d_diff_controller
+#define jinit_d_main_controller gdcm_jpeg8_jinit_d_main_controller
+#define jinit_d_post_controller gdcm_jpeg8_jinit_d_post_controller
+#define jinit_d_scaler gdcm_jpeg8_jinit_d_scaler
+#define jinit_differencer gdcm_jpeg8_jinit_differencer
+#define jinit_downsampler gdcm_jpeg8_jinit_downsampler
+#define jinit_forward_dct gdcm_jpeg8_jinit_forward_dct
+#define jinit_input_controller gdcm_jpeg8_jinit_input_controller
+#define jinit_inverse_dct gdcm_jpeg8_jinit_inverse_dct
+#define jinit_lhuff_decoder gdcm_jpeg8_jinit_lhuff_decoder
+#define jinit_lhuff_encoder gdcm_jpeg8_jinit_lhuff_encoder
+#define jinit_lossless_c_codec gdcm_jpeg8_jinit_lossless_c_codec
+#define jinit_lossless_d_codec gdcm_jpeg8_jinit_lossless_d_codec
+#define jinit_lossy_c_codec gdcm_jpeg8_jinit_lossy_c_codec
+#define jinit_lossy_d_codec gdcm_jpeg8_jinit_lossy_d_codec
+#define jinit_marker_reader gdcm_jpeg8_jinit_marker_reader
+#define jinit_marker_writer gdcm_jpeg8_jinit_marker_writer
+#define jinit_master_decompress gdcm_jpeg8_jinit_master_decompress
+#define jinit_memory_mgr gdcm_jpeg8_jinit_memory_mgr
+#define jinit_merged_upsampler gdcm_jpeg8_jinit_merged_upsampler
+#define jinit_phuff_decoder gdcm_jpeg8_jinit_phuff_decoder
+#define jinit_phuff_encoder gdcm_jpeg8_jinit_phuff_encoder
+#define jinit_shuff_decoder gdcm_jpeg8_jinit_shuff_decoder
+#define jinit_shuff_encoder gdcm_jpeg8_jinit_shuff_encoder
+#define jinit_undifferencer gdcm_jpeg8_jinit_undifferencer
+#define jinit_upsampler gdcm_jpeg8_jinit_upsampler
+#define jpeg_CreateCompress gdcm_jpeg8_jpeg_CreateCompress
+#define jpeg_CreateDecompress gdcm_jpeg8_jpeg_CreateDecompress
+#define jpeg_abort gdcm_jpeg8_jpeg_abort
+#define jpeg_abort_compress gdcm_jpeg8_jpeg_abort_compress
+#define jpeg_abort_decompress gdcm_jpeg8_jpeg_abort_decompress
+#define jpeg_add_quant_table gdcm_jpeg8_jpeg_add_quant_table
+#define jpeg_alloc_huff_table gdcm_jpeg8_jpeg_alloc_huff_table
+#define jpeg_alloc_quant_table gdcm_jpeg8_jpeg_alloc_quant_table
+#define jpeg_calc_output_dimensions gdcm_jpeg8_jpeg_calc_output_dimensions
+#define jpeg_consume_input gdcm_jpeg8_jpeg_consume_input
+#define jpeg_copy_critical_parameters gdcm_jpeg8_jpeg_copy_critical_parameters
+#define jpeg_default_colorspace gdcm_jpeg8_jpeg_default_colorspace
+#define jpeg_destroy gdcm_jpeg8_jpeg_destroy
+#define jpeg_destroy_compress gdcm_jpeg8_jpeg_destroy_compress
+#define jpeg_destroy_decompress gdcm_jpeg8_jpeg_destroy_decompress
+#define jpeg_fdct_float gdcm_jpeg8_jpeg_fdct_float
+#define jpeg_fdct_ifast gdcm_jpeg8_jpeg_fdct_ifast
+#define jpeg_fdct_islow gdcm_jpeg8_jpeg_fdct_islow
+#define jpeg_fill_bit_buffer gdcm_jpeg8_jpeg_fill_bit_buffer
+#define jpeg_finish_compress gdcm_jpeg8_jpeg_finish_compress
+#define jpeg_finish_decompress gdcm_jpeg8_jpeg_finish_decompress
+#define jpeg_finish_output gdcm_jpeg8_jpeg_finish_output
+#define jpeg_free_large gdcm_jpeg8_jpeg_free_large
+#define jpeg_free_small gdcm_jpeg8_jpeg_free_small
+#define jpeg_gen_optimal_table gdcm_jpeg8_jpeg_gen_optimal_table
+#define jpeg_get_large gdcm_jpeg8_jpeg_get_large
+#define jpeg_get_small gdcm_jpeg8_jpeg_get_small
+#define jpeg_has_multiple_scans gdcm_jpeg8_jpeg_has_multiple_scans
+#define jpeg_huff_decode gdcm_jpeg8_jpeg_huff_decode
+#define jpeg_idct_1x1 gdcm_jpeg8_jpeg_idct_1x1
+#define jpeg_idct_2x2 gdcm_jpeg8_jpeg_idct_2x2
+#define jpeg_idct_4x4 gdcm_jpeg8_jpeg_idct_4x4
+#define jpeg_idct_float gdcm_jpeg8_jpeg_idct_float
+#define jpeg_idct_ifast gdcm_jpeg8_jpeg_idct_ifast
+#define jpeg_idct_islow gdcm_jpeg8_jpeg_idct_islow
+#define jpeg_input_complete gdcm_jpeg8_jpeg_input_complete
+#define jpeg_make_c_derived_tbl gdcm_jpeg8_jpeg_make_c_derived_tbl
+#define jpeg_make_d_derived_tbl gdcm_jpeg8_jpeg_make_d_derived_tbl
+#define jpeg_mem_available gdcm_jpeg8_jpeg_mem_available
+#define jpeg_mem_init gdcm_jpeg8_jpeg_mem_init
+#define jpeg_mem_term gdcm_jpeg8_jpeg_mem_term
+#define jpeg_natural_order gdcm_jpeg8_jpeg_natural_order
+#define jpeg_new_colormap gdcm_jpeg8_jpeg_new_colormap
+#define jpeg_open_backing_store gdcm_jpeg8_jpeg_open_backing_store
+#define jpeg_quality_scaling gdcm_jpeg8_jpeg_quality_scaling
+#define jpeg_read_coefficients gdcm_jpeg8_jpeg_read_coefficients
+#define jpeg_read_header gdcm_jpeg8_jpeg_read_header
+#define jpeg_read_raw_data gdcm_jpeg8_jpeg_read_raw_data
+#define jpeg_read_scanlines gdcm_jpeg8_jpeg_read_scanlines
+#define jpeg_resync_to_restart gdcm_jpeg8_jpeg_resync_to_restart
+#define jpeg_save_markers gdcm_jpeg8_jpeg_save_markers
+#define jpeg_set_colorspace gdcm_jpeg8_jpeg_set_colorspace
+#define jpeg_set_defaults gdcm_jpeg8_jpeg_set_defaults
+#define jpeg_set_linear_quality gdcm_jpeg8_jpeg_set_linear_quality
+#define jpeg_set_marker_processor gdcm_jpeg8_jpeg_set_marker_processor
+#define jpeg_set_quality gdcm_jpeg8_jpeg_set_quality
+#define jpeg_simple_lossless gdcm_jpeg8_jpeg_simple_lossless
+#define jpeg_simple_progression gdcm_jpeg8_jpeg_simple_progression
+#define jpeg_start_compress gdcm_jpeg8_jpeg_start_compress
+#define jpeg_start_decompress gdcm_jpeg8_jpeg_start_decompress
+#define jpeg_start_output gdcm_jpeg8_jpeg_start_output
+#define jpeg_std_error gdcm_jpeg8_jpeg_std_error
+#define jpeg_std_message_table gdcm_jpeg8_jpeg_std_message_table
+#define jpeg_stdio_dest gdcm_jpeg8_jpeg_stdio_dest
+#define jpeg_stdio_src gdcm_jpeg8_jpeg_stdio_src
+#define jpeg_suppress_tables gdcm_jpeg8_jpeg_suppress_tables
+#define jpeg_write_coefficients gdcm_jpeg8_jpeg_write_coefficients
+#define jpeg_write_m_byte gdcm_jpeg8_jpeg_write_m_byte
+#define jpeg_write_m_header gdcm_jpeg8_jpeg_write_m_header
+#define jpeg_write_marker gdcm_jpeg8_jpeg_write_marker
+#define jpeg_write_raw_data gdcm_jpeg8_jpeg_write_raw_data
+#define jpeg_write_scanlines gdcm_jpeg8_jpeg_write_scanlines
+#define jpeg_write_tables gdcm_jpeg8_jpeg_write_tables
+#define jround_up gdcm_jpeg8_jround_up
+#define jzero_far gdcm_jpeg8_jzero_far
+
+
+#endif
--- /dev/null
+IJG JPEG LIBRARY: SYSTEM ARCHITECTURE
+
+Copyright (C) 1991-1995, Thomas G. Lane.
+This file is part of the Independent JPEG Group's software.
+For conditions of distribution and use, see the accompanying README file.
+
+
+This file provides an overview of the architecture of the IJG JPEG software;
+that is, the functions of the various modules in the system and the interfaces
+between modules. For more precise details about any data structure or calling
+convention, see the include files and comments in the source code.
+
+We assume that the reader is already somewhat familiar with the JPEG standard.
+The README file includes references for learning about JPEG. The file
+libjpeg.doc describes the library from the viewpoint of an application
+programmer using the library; it's best to read that file before this one.
+Also, the file coderules.doc describes the coding style conventions we use.
+
+In this document, JPEG-specific terminology follows the JPEG standard:
+ A "component" means a color channel, e.g., Red or Luminance.
+ A "sample" is a single component value (i.e., one number in the image data).
+ A "coefficient" is a frequency coefficient (a DCT transform output number).
+ A "block" is an 8x8 group of samples or coefficients.
+ A "data unit" is an abstract data type which is either a block for lossy
+ (DCT-based) codecs or a sample for lossless (predictive) codecs.
+ An "MCU" (minimum coded unit) is an interleaved set of data units of size
+ determined by the sampling factors, or a single data unit in a
+ noninterleaved scan.
+We do not use the terms "pixel" and "sample" interchangeably. When we say
+pixel, we mean an element of the full-size image, while a sample is an element
+of the downsampled image. Thus the number of samples may vary across
+components while the number of pixels does not. (This terminology is not used
+rigorously throughout the code, but it is used in places where confusion would
+otherwise result.)
+
+
+*** System features ***
+
+The IJG distribution contains two parts:
+ * A subroutine library for JPEG compression and decompression.
+ * cjpeg/djpeg, two sample applications that use the library to transform
+ JFIF JPEG files to and from several other image formats.
+cjpeg/djpeg are of no great intellectual complexity: they merely add a simple
+command-line user interface and I/O routines for several uncompressed image
+formats. This document concentrates on the library itself.
+
+We desire the library to be capable of supporting all JPEG baseline, extended
+sequential, and progressive DCT processes, as well as the lossless (spatial)
+process. Hierarchical processes are not supported.
+
+Within these limits, any set of compression parameters allowed by the JPEG
+spec should be readable for decompression. (We can be more restrictive about
+what formats we can generate.) Although the system design allows for all
+parameter values, some uncommon settings are not yet implemented and may
+never be; nonintegral sampling ratios are the prime example. Furthermore,
+we treat 8-bit vs. 12-bit data precision as a compile-time switch, not a
+run-time option, because most machines can store 8-bit pixels much more
+compactly than 12-bit.
+
+For legal reasons, JPEG arithmetic coding is not currently supported, but
+extending the library to include it would be straightforward.
+
+By itself, the library handles only interchange JPEG datastreams --- in
+particular the widely used JFIF file format. The library can be used by
+surrounding code to process interchange or abbreviated JPEG datastreams that
+are embedded in more complex file formats. (For example, libtiff uses this
+library to implement JPEG compression within the TIFF file format.)
+
+The library includes a substantial amount of code that is not covered by the
+JPEG standard but is necessary for typical applications of JPEG. These
+functions preprocess the image before JPEG compression or postprocess it after
+decompression. They include colorspace conversion, downsampling/upsampling,
+and color quantization. This code can be omitted if not needed.
+
+A wide range of quality vs. speed tradeoffs are possible in JPEG processing,
+and even more so in decompression postprocessing. The decompression library
+provides multiple implementations that cover most of the useful tradeoffs,
+ranging from very-high-quality down to fast-preview operation. On the
+compression side we have generally not provided low-quality choices, since
+compression is normally less time-critical. It should be understood that the
+low-quality modes may not meet the JPEG standard's accuracy requirements;
+nonetheless, they are useful for viewers.
+
+
+*** Portability issues ***
+
+Portability is an essential requirement for the library. The key portability
+issues that show up at the level of system architecture are:
+
+1. Memory usage. We want the code to be able to run on PC-class machines
+with limited memory. Images should therefore be processed sequentially (in
+strips), to avoid holding the whole image in memory at once. Where a
+full-image buffer is necessary, we should be able to use either virtual memory
+or temporary files.
+
+2. Near/far pointer distinction. To run efficiently on 80x86 machines, the
+code should distinguish "small" objects (kept in near data space) from
+"large" ones (kept in far data space). This is an annoying restriction, but
+fortunately it does not impact code quality for less brain-damaged machines,
+and the source code clutter turns out to be minimal with sufficient use of
+pointer typedefs.
+
+3. Data precision. We assume that "char" is at least 8 bits, "short" and
+"int" at least 16, "long" at least 32. The code will work fine with larger
+data sizes, although memory may be used inefficiently in some cases. However,
+the JPEG compressed datastream must ultimately appear on external storage as a
+sequence of 8-bit bytes if it is to conform to the standard. This may pose a
+problem on machines where char is wider than 8 bits. The library represents
+compressed data as an array of values of typedef JOCTET. If no data type
+exactly 8 bits wide is available, custom data source and data destination
+modules must be written to unpack and pack the chosen JOCTET datatype into
+8-bit external representation.
+
+
+*** System overview ***
+
+The compressor and decompressor are each divided into two main sections:
+the JPEG compressor or decompressor proper, and the preprocessing or
+postprocessing functions. The interface between these two sections is the
+image data that the official JPEG spec regards as its input or output: this
+data is in the colorspace to be used for compression, and it is downsampled
+to the sampling factors to be used. The preprocessing and postprocessing
+steps are responsible for converting a normal image representation to or from
+this form. (Those few applications that want to deal with YCbCr downsampled
+data can skip the preprocessing or postprocessing step.)
+
+Looking more closely, the compressor library contains the following main
+elements:
+
+ Preprocessing:
+ * Color space conversion (e.g., RGB to YCbCr).
+ * Edge expansion and downsampling. Optionally, this step can do simple
+ smoothing --- this is often helpful for low-quality source data.
+ Lossy JPEG proper:
+ * MCU assembly, DCT, quantization.
+ * Entropy coding (sequential or progressive, Huffman or arithmetic).
+ Lossless JPEG proper:
+ * Point transform.
+ * Prediction, differencing.
+ * Entropy coding (Huffman or arithmetic)
+
+In addition to these modules we need overall control, marker generation,
+and support code (memory management & error handling). There is also a
+module responsible for physically writing the output data --- typically
+this is just an interface to fwrite(), but some applications may need to
+do something else with the data.
+
+The decompressor library contains the following main elements:
+
+ Lossy JPEG proper:
+ * Entropy decoding (sequential or progressive, Huffman or arithmetic).
+ * Dequantization, inverse DCT, MCU disassembly.
+ Lossless JPEG proper:
+ * Entropy decoding (Huffman or arithmetic).
+ * Prediction, undifferencing.
+ * Point transform, sample size scaling.
+ Postprocessing:
+ * Upsampling. Optionally, this step may be able to do more general
+ rescaling of the image.
+ * Color space conversion (e.g., YCbCr to RGB). This step may also
+ provide gamma adjustment [ currently it does not ].
+ * Optional color quantization (e.g., reduction to 256 colors).
+ * Optional color precision reduction (e.g., 24-bit to 15-bit color).
+ [This feature is not currently implemented.]
+
+We also need overall control, marker parsing, and a data source module.
+The support code (memory management & error handling) can be shared with
+the compression half of the library.
+
+There may be several implementations of each of these elements, particularly
+in the decompressor, where a wide range of speed/quality tradeoffs is very
+useful. It must be understood that some of the best speedups involve
+merging adjacent steps in the pipeline. For example, upsampling, color space
+conversion, and color quantization might all be done at once when using a
+low-quality ordered-dither technique. The system architecture is designed to
+allow such merging where appropriate.
+
+
+Note: it is convenient to regard edge expansion (padding to block boundaries)
+as a preprocessing/postprocessing function, even though the JPEG spec includes
+it in compression/decompression. We do this because downsampling/upsampling
+can be simplified a little if they work on padded data: it's not necessary to
+have special cases at the right and bottom edges. Therefore the interface
+buffer is always an integral number of blocks wide and high, and we expect
+compression preprocessing to pad the source data properly. Padding will occur
+only to the next block (8-sample) boundary. In an interleaved-scan situation,
+additional dummy blocks may be used to fill out MCUs, but the MCU assembly and
+disassembly logic will create or discard these blocks internally. (This is
+advantageous for speed reasons, since we avoid DCTing the dummy blocks.
+It also permits a small reduction in file size, because the compressor can
+choose dummy block contents so as to minimize their size in compressed form.
+Finally, it makes the interface buffer specification independent of whether
+the file is actually interleaved or not.) Applications that wish to deal
+directly with the downsampled data must provide similar buffering and padding
+for odd-sized images.
+
+
+*** Poor man's object-oriented programming ***
+
+It should be clear by now that we have a lot of quasi-independent processing
+steps, many of which have several possible behaviors. To avoid cluttering the
+code with lots of switch statements, we use a simple form of object-style
+programming to separate out the different possibilities.
+
+For example, two different color quantization algorithms could be implemented
+as two separate modules that present the same external interface; at runtime,
+the calling code will access the proper module indirectly through an "object".
+
+We can get the limited features we need while staying within portable C.
+The basic tool is a function pointer. An "object" is just a struct
+containing one or more function pointer fields, each of which corresponds to
+a method name in real object-oriented languages. During initialization we
+fill in the function pointers with references to whichever module we have
+determined we need to use in this run. Then invocation of the module is done
+by indirecting through a function pointer; on most machines this is no more
+expensive than a switch statement, which would be the only other way of
+making the required run-time choice. The really significant benefit, of
+course, is keeping the source code clean and well structured.
+
+We can also arrange to have private storage that varies between different
+implementations of the same kind of object. We do this by making all the
+module-specific object structs be separately allocated entities, which will
+be accessed via pointers in the master compression or decompression struct.
+The "public" fields or methods for a given kind of object are specified by
+a commonly known struct. But a module's initialization code can allocate
+a larger struct that contains the common struct as its first member, plus
+additional private fields. With appropriate pointer casting, the module's
+internal functions can access these private fields. (For a simple example,
+see jdatadst.c, which implements the external interface specified by struct
+jpeg_destination_mgr, but adds extra fields.)
+
+(Of course this would all be a lot easier if we were using C++, but we are
+not yet prepared to assume that everyone has a C++ compiler.)
+
+An important benefit of this scheme is that it is easy to provide multiple
+versions of any method, each tuned to a particular case. While a lot of
+precalculation might be done to select an optimal implementation of a method,
+the cost per invocation is constant. For example, the upsampling step might
+have a "generic" method, plus one or more "hardwired" methods for the most
+popular sampling factors; the hardwired methods would be faster because they'd
+use straight-line code instead of for-loops. The cost to determine which
+method to use is paid only once, at startup, and the selection criteria are
+hidden from the callers of the method.
+
+This plan differs a little bit from usual object-oriented structures, in that
+only one instance of each object class will exist during execution. The
+reason for having the class structure is that on different runs we may create
+different instances (choose to execute different modules). You can think of
+the term "method" as denoting the common interface presented by a particular
+set of interchangeable functions, and "object" as denoting a group of related
+methods, or the total shared interface behavior of a group of modules.
+
+
+*** Overall control structure ***
+
+We previously mentioned the need for overall control logic in the compression
+and decompression libraries. In IJG implementations prior to v5, overall
+control was mostly provided by "pipeline control" modules, which proved to be
+large, unwieldy, and hard to understand. To improve the situation, the
+control logic has been subdivided into multiple modules. The control modules
+consist of:
+
+1. Master control for module selection and initialization. This has two
+responsibilities:
+
+ 1A. Startup initialization at the beginning of image processing.
+ The individual processing modules to be used in this run are selected
+ and given initialization calls.
+
+ 1B. Per-pass control. This determines how many passes will be performed
+ and calls each active processing module to configure itself
+ appropriately at the beginning of each pass. End-of-pass processing,
+ where necessary, is also invoked from the master control module.
+
+ Method selection is partially distributed, in that a particular processing
+ module may contain several possible implementations of a particular method,
+ which it will select among when given its initialization call. The master
+ control code need only be concerned with decisions that affect more than
+ one module.
+
+2. Data buffering control. A separate control module exists for each
+ inter-processing-step data buffer. This module is responsible for
+ invoking the processing steps that write or read that data buffer.
+
+Each buffer controller sees the world as follows:
+
+input data => processing step A => buffer => processing step B => output data
+ | | |
+ ------------------ controller ------------------
+
+The controller knows the dataflow requirements of steps A and B: how much data
+they want to accept in one chunk and how much they output in one chunk. Its
+function is to manage its buffer and call A and B at the proper times.
+
+A data buffer control module may itself be viewed as a processing step by a
+higher-level control module; thus the control modules form a binary tree with
+elementary processing steps at the leaves of the tree.
+
+The control modules are objects. A considerable amount of flexibility can
+be had by replacing implementations of a control module. For example:
+* Merging of adjacent steps in the pipeline is done by replacing a control
+ module and its pair of processing-step modules with a single processing-
+ step module. (Hence the possible merges are determined by the tree of
+ control modules.)
+* In some processing modes, a given interstep buffer need only be a "strip"
+ buffer large enough to accommodate the desired data chunk sizes. In other
+ modes, a full-image buffer is needed and several passes are required.
+ The control module determines which kind of buffer is used and manipulates
+ virtual array buffers as needed. One or both processing steps may be
+ unaware of the multi-pass behavior.
+
+In theory, we might be able to make all of the data buffer controllers
+interchangeable and provide just one set of implementations for all. In
+practice, each one contains considerable special-case processing for its
+particular job. The buffer controller concept should be regarded as an
+overall system structuring principle, not as a complete description of the
+task performed by any one controller.
+
+
+*** Codec object structure ***
+
+As noted above, this library supports both the lossy (DCT-based) and lossless
+JPEG processes. Because these processes have little in common with one another
+(and their implementations share very little code), we need to provide a way to
+isloate the underlying JPEG process from the rest of the library. This is
+accomplished by introducing an abstract "codec object" which acts a generic
+interface to the JPEG (de)compressor proper.
+
+Using the power of the object-oriented scheme described above, we build the
+lossy and lossless modules as two separate implementations of the codec object.
+Switching between lossy and lossless processes then becomes as trivial as
+assigning the appropriate method pointers during initialization of the library.
+
+
+*** Compression object structure ***
+
+Here is a sketch of the logical structure of the JPEG compression library:
+
+ |-- Colorspace conversion
+ |-- Preprocessing controller --|
+ | |-- Downsampling
+ |
+Main controller --|
+ | /--> Lossy codec
+ | /
+ |-- Compression codec < *OR*
+ \
+ \--> Lossless codec
+
+
+where the lossy codec looks like:
+
+ |-- Forward DCT, quantize
+<-- Coefficient controller --|
+ |-- Entropy encoding
+
+
+and the lossless codec looks like:
+
+ |-- Point transformation
+ |
+<-- Difference controller --|-- Prediction, differencing
+ |
+ |-- Lossless entropy encoding
+
+
+This sketch also describes the flow of control (subroutine calls) during
+typical image data processing. Each of the components shown in the diagram is
+an "object" which may have several different implementations available. One
+or more source code files contain the actual implementation(s) of each object.
+
+The objects shown above are:
+
+* Main controller: buffer controller for the subsampled-data buffer, which
+ holds the preprocessed input data. This controller invokes preprocessing to
+ fill the subsampled-data buffer, and JPEG compression to empty it. There is
+ usually no need for a full-image buffer here; a strip buffer is adequate.
+
+* Preprocessing controller: buffer controller for the downsampling input data
+ buffer, which lies between colorspace conversion and downsampling. Note
+ that a unified conversion/downsampling module would probably replace this
+ controller entirely.
+
+* Colorspace conversion: converts application image data into the desired
+ JPEG color space; also changes the data from pixel-interleaved layout to
+ separate component planes. Processes one pixel row at a time.
+
+* Downsampling: performs reduction of chroma components as required.
+ Optionally may perform pixel-level smoothing as well. Processes a "row
+ group" at a time, where a row group is defined as Vmax pixel rows of each
+ component before downsampling, and Vk sample rows afterwards (remember Vk
+ differs across components). Some downsampling or smoothing algorithms may
+ require context rows above and below the current row group; the
+ preprocessing controller is responsible for supplying these rows via proper
+ buffering. The downsampler is responsible for edge expansion at the right
+ edge (i.e., extending each sample row to a multiple of 8 samples); but the
+ preprocessing controller is responsible for vertical edge expansion (i.e.,
+ duplicating the bottom sample row as needed to make a multiple of 8 rows).
+
+* Coefficient controller: buffer controller for the DCT-coefficient data.
+ This controller handles MCU assembly, including insertion of dummy DCT
+ blocks when needed at the right or bottom edge. When performing
+ Huffman-code optimization or emitting a multiscan JPEG file, this
+ controller is responsible for buffering the full image. The equivalent of
+ one fully interleaved MCU row of subsampled data is processed per call,
+ even when the JPEG file is noninterleaved.
+
+* Forward DCT and quantization: Perform DCT, quantize, and emit coefficients.
+ Works on one or more DCT blocks at a time. (Note: the coefficients are now
+ emitted in normal array order, which the entropy encoder is expected to
+ convert to zigzag order as necessary. Prior versions of the IJG code did
+ the conversion to zigzag order within the quantization step.)
+
+* Entropy encoding: Perform Huffman or arithmetic entropy coding and emit the
+ coded data to the data destination module. Works on one MCU per call.
+ For progressive JPEG, the same DCT blocks are fed to the entropy coder
+ during each pass, and the coder must emit the appropriate subset of
+ coefficients.
+
+* Difference controller: buffer controller for the spatial difference data.
+ When emitting a multiscan JPEG file, this controller is responsible for
+ buffering the full image. The equivalent of one fully interleaved MCU row
+ of subsampled data is processed per call, even when the JPEG file is
+ noninterleaved.
+
+* Point transformation: Scale the data down by the point transformation
+ parameter.
+
+* Prediction and differencing: Calculate the predictor and subtract it
+ from the input. Works on one scanline per call. The difference
+ controller supplies the prior scanline which is used for prediction.
+
+* Lossless entropy encoding: Perform Huffman or arithmetic entropy coding and
+ emit the coded data to the data destination module. This module handles MCU
+ assembly. Works on one MCU-row per call.
+
+In addition to the above objects, the compression library includes these
+objects:
+
+* Master control: determines the number of passes required, controls overall
+ and per-pass initialization of the other modules.
+
+* Marker writing: generates JPEG markers (except for RSTn, which is emitted
+ by the entropy encoder when needed).
+
+* Data destination manager: writes the output JPEG datastream to its final
+ destination (e.g., a file). The destination manager supplied with the
+ library knows how to write to a stdio stream; for other behaviors, the
+ surrounding application may provide its own destination manager.
+
+* Memory manager: allocates and releases memory, controls virtual arrays
+ (with backing store management, where required).
+
+* Error handler: performs formatting and output of error and trace messages;
+ determines handling of nonfatal errors. The surrounding application may
+ override some or all of this object's methods to change error handling.
+
+* Progress monitor: supports output of "percent-done" progress reports.
+ This object represents an optional callback to the surrounding application:
+ if wanted, it must be supplied by the application.
+
+The error handler, destination manager, and progress monitor objects are
+defined as separate objects in order to simplify application-specific
+customization of the JPEG library. A surrounding application may override
+individual methods or supply its own all-new implementation of one of these
+objects. The object interfaces for these objects are therefore treated as
+part of the application interface of the library, whereas the other objects
+are internal to the library.
+
+The error handler and memory manager are shared by JPEG compression and
+decompression; the progress monitor, if used, may be shared as well.
+
+
+*** Decompression object structure ***
+
+Here is a sketch of the logical structure of the JPEG decompression library:
+
+ /--> Lossy codec
+ /
+ |-- Decompression codec < *OR*
+ | \
+ | \--> Lossless codec
+Main controller --|
+ |
+ | |-- Upsampling
+ |-- Postprocessing controller --| |-- Colorspace conversion
+ |-- Color quantization
+ |-- Color precision reduction
+
+
+where the lossy codec looks like:
+
+ |-- Entropy decoding
+<-- Coefficient controller --|
+ |-- Dequantize, Inverse DCT
+
+
+and the lossless codec looks like:
+
+ |-- Lossless entropy decoding
+ |
+<-- Difference controller --|-- Prediction, undifferencing
+ |
+ |-- Point transformation, sample size scaling
+
+
+As before, this diagram also represents typical control flow. The objects
+shown are:
+
+* Main controller: buffer controller for the subsampled-data buffer, which
+ holds the output of JPEG decompression proper. This controller's primary
+ task is to feed the postprocessing procedure. Some upsampling algorithms
+ may require context rows above and below the current row group; when this
+ is true, the main controller is responsible for managing its buffer so as
+ to make context rows available. In the current design, the main buffer is
+ always a strip buffer; a full-image buffer is never required.
+
+* Coefficient controller: buffer controller for the DCT-coefficient data.
+ This controller handles MCU disassembly, including deletion of any dummy
+ DCT blocks at the right or bottom edge. When reading a multiscan JPEG
+ file, this controller is responsible for buffering the full image.
+ (Buffering DCT coefficients, rather than samples, is necessary to support
+ progressive JPEG.) The equivalent of one fully interleaved MCU row of
+ subsampled data is processed per call, even when the source JPEG file is
+ noninterleaved.
+
+* Entropy decoding: Read coded data from the data source module and perform
+ Huffman or arithmetic entropy decoding. Works on one MCU per call.
+ For progressive JPEG decoding, the coefficient controller supplies the prior
+ coefficients of each MCU (initially all zeroes), which the entropy decoder
+ modifies in each scan.
+
+* Dequantization and inverse DCT: like it says. Note that the coefficients
+ buffered by the coefficient controller have NOT been dequantized; we
+ merge dequantization and inverse DCT into a single step for speed reasons.
+ When scaled-down output is asked for, simplified DCT algorithms may be used
+ that emit only 1x1, 2x2, or 4x4 samples per DCT block, not the full 8x8.
+ Works on one DCT block at a time.
+
+* Difference controller: buffer controller for the spatial difference data.
+ When reading a multiscan JPEG file, this controller is responsible for
+ buffering the full image. The equivalent of one fully interleaved MCU row
+ is processed per call, even when the source JPEG file is noninterleaved.
+
+* Lossless entropy decoding: Read coded data from the data source module and
+ perform Huffman or arithmetic entropy decoding. Works on one MCU-row per
+ call.
+
+* Prediction and undifferencing: Calculate the predictor and add it to the
+ decoded difference. Works on one scanline per call. The difference
+ controller supplies the prior scanline which is used for prediction.
+
+* Point transform and sample size scaling: Scale the data up by the point
+ transformation parameter and scale it down to fit into the compiled-in
+ sample size.
+
+* Postprocessing controller: buffer controller for the color quantization
+ input buffer, when quantization is in use. (Without quantization, this
+ controller just calls the upsampler.) For two-pass quantization, this
+ controller is responsible for buffering the full-image data.
+
+* Upsampling: restores chroma components to full size. (May support more
+ general output rescaling, too. Note that if undersized DCT outputs have
+ been emitted by the DCT module, this module must adjust so that properly
+ sized outputs are created.) Works on one row group at a time. This module
+ also calls the color conversion module, so its top level is effectively a
+ buffer controller for the upsampling->color conversion buffer. However, in
+ all but the highest-quality operating modes, upsampling and color
+ conversion are likely to be merged into a single step.
+
+* Colorspace conversion: convert from JPEG color space to output color space,
+ and change data layout from separate component planes to pixel-interleaved.
+ Works on one pixel row at a time.
+
+* Color quantization: reduce the data to colormapped form, using either an
+ externally specified colormap or an internally generated one. This module
+ is not used for full-color output. Works on one pixel row at a time; may
+ require two passes to generate a color map. Note that the output will
+ always be a single component representing colormap indexes. In the current
+ design, the output values are JSAMPLEs, so an 8-bit compilation cannot
+ quantize to more than 256 colors. This is unlikely to be a problem in
+ practice.
+
+* Color reduction: this module handles color precision reduction, e.g.,
+ generating 15-bit color (5 bits/primary) from JPEG's 24-bit output.
+ Not quite clear yet how this should be handled... should we merge it with
+ colorspace conversion???
+
+Note that some high-speed operating modes might condense the entire
+postprocessing sequence to a single module (upsample, color convert, and
+quantize in one step).
+
+In addition to the above objects, the decompression library includes these
+objects:
+
+* Master control: determines the number of passes required, controls overall
+ and per-pass initialization of the other modules. This is subdivided into
+ input and output control: jdinput.c controls only input-side processing,
+ while jdmaster.c handles overall initialization and output-side control.
+
+* Marker reading: decodes JPEG markers (except for RSTn).
+
+* Data source manager: supplies the input JPEG datastream. The source
+ manager supplied with the library knows how to read from a stdio stream;
+ for other behaviors, the surrounding application may provide its own source
+ manager.
+
+* Memory manager: same as for compression library.
+
+* Error handler: same as for compression library.
+
+* Progress monitor: same as for compression library.
+
+As with compression, the data source manager, error handler, and progress
+monitor are candidates for replacement by a surrounding application.
+
+
+*** Decompression input and output separation ***
+
+To support efficient incremental display of progressive JPEG files, the
+decompressor is divided into two sections that can run independently:
+
+1. Data input includes marker parsing, entropy decoding, and input into the
+ coefficient controller's DCT coefficient buffer. Note that this
+ processing is relatively cheap and fast.
+
+2. Data output reads from the DCT coefficient buffer and performs the IDCT
+ and all postprocessing steps.
+
+For a progressive JPEG file, the data input processing is allowed to get
+arbitrarily far ahead of the data output processing. (This occurs only
+if the application calls jpeg_consume_input(); otherwise input and output
+run in lockstep, since the input section is called only when the output
+section needs more data.) In this way the application can avoid making
+extra display passes when data is arriving faster than the display pass
+can run. Furthermore, it is possible to abort an output pass without
+losing anything, since the coefficient buffer is read-only as far as the
+output section is concerned. See libjpeg.doc for more detail.
+
+A full-image coefficient array is only created if the JPEG file has multiple
+scans (or if the application specifies buffered-image mode anyway). When
+reading a single-scan file, the coefficient controller normally creates only
+a one-MCU buffer, so input and output processing must run in lockstep in this
+case. jpeg_consume_input() is effectively a no-op in this situation.
+
+The main impact of dividing the decompressor in this fashion is that we must
+be very careful with shared variables in the cinfo data structure. Each
+variable that can change during the course of decompression must be
+classified as belonging to data input or data output, and each section must
+look only at its own variables. For example, the data output section may not
+depend on any of the variables that describe the current scan in the JPEG
+file, because these may change as the data input section advances into a new
+scan.
+
+The progress monitor is (somewhat arbitrarily) defined to treat input of the
+file as one pass when buffered-image mode is not used, and to ignore data
+input work completely when buffered-image mode is used. Note that the
+library has no reliable way to predict the number of passes when dealing
+with a progressive JPEG file, nor can it predict the number of output passes
+in buffered-image mode. So the work estimate is inherently bogus anyway.
+
+No comparable division is currently made in the compression library, because
+there isn't any real need for it.
+
+
+*** Data formats ***
+
+Arrays of pixel sample values use the following data structure:
+
+ typedef something JSAMPLE; a pixel component value, 0..MAXJSAMPLE
+ typedef JSAMPLE *JSAMPROW; ptr to a row of samples
+ typedef JSAMPROW *JSAMPARRAY; ptr to a list of rows
+ typedef JSAMPARRAY *JSAMPIMAGE; ptr to a list of color-component arrays
+
+The basic element type JSAMPLE will typically be one of unsigned char,
+(signed) char, or short. Short will be used if samples wider than 8 bits are
+to be supported (this is a compile-time option). Otherwise, unsigned char is
+used if possible. If the compiler only supports signed chars, then it is
+necessary to mask off the value when reading. Thus, all reads of JSAMPLE
+values must be coded as "GETJSAMPLE(value)", where the macro will be defined
+as "((value) & 0xFF)" on signed-char machines and "((int) (value))" elsewhere.
+
+With these conventions, JSAMPLE values can be assumed to be >= 0. This helps
+simplify correct rounding during downsampling, etc. The JPEG standard's
+specification that sample values run from -128..127 is accommodated by
+subtracting 128 just as the sample value is copied into the source array for
+the DCT step (this will be an array of signed ints). Similarly, during
+decompression the output of the IDCT step will be immediately shifted back to
+0..255. (NB: different values are required when 12-bit samples are in use.
+The code is written in terms of MAXJSAMPLE and CENTERJSAMPLE, which will be
+defined as 255 and 128 respectively in an 8-bit implementation, and as 4095
+and 2048 in a 12-bit implementation.)
+
+We use a pointer per row, rather than a two-dimensional JSAMPLE array. This
+choice costs only a small amount of memory and has several benefits:
+* Code using the data structure doesn't need to know the allocated width of
+ the rows. This simplifies edge expansion/compression, since we can work
+ in an array that's wider than the logical picture width.
+* Indexing doesn't require multiplication; this is a performance win on many
+ machines.
+* Arrays with more than 64K total elements can be supported even on machines
+ where malloc() cannot allocate chunks larger than 64K.
+* The rows forming a component array may be allocated at different times
+ without extra copying. This trick allows some speedups in smoothing steps
+ that need access to the previous and next rows.
+
+Note that each color component is stored in a separate array; we don't use the
+traditional layout in which the components of a pixel are stored together.
+This simplifies coding of modules that work on each component independently,
+because they don't need to know how many components there are. Furthermore,
+we can read or write each component to a temporary file independently, which
+is helpful when dealing with noninterleaved JPEG files.
+
+In general, a specific sample value is accessed by code such as
+ GETJSAMPLE(image[colorcomponent][row][col])
+where col is measured from the image left edge, but row is measured from the
+first sample row currently in memory. Either of the first two indexings can
+be precomputed by copying the relevant pointer.
+
+
+Since most image-processing applications prefer to work on images in which
+the components of a pixel are stored together, the data passed to or from the
+surrounding application uses the traditional convention: a single pixel is
+represented by N consecutive JSAMPLE values, and an image row is an array of
+(# of color components)*(image width) JSAMPLEs. One or more rows of data can
+be represented by a pointer of type JSAMPARRAY in this scheme. This scheme is
+converted to component-wise storage inside the JPEG library. (Applications
+that want to skip JPEG preprocessing or postprocessing will have to contend
+with component-wise storage.)
+
+
+Arrays of DCT-coefficient values use the following data structure:
+
+ typedef short JCOEF; a 16-bit signed integer
+ typedef JCOEF JBLOCK[DCTSIZE2]; an 8x8 block of coefficients
+ typedef JBLOCK *JBLOCKROW; ptr to one horizontal row of 8x8 blocks
+ typedef JBLOCKROW *JBLOCKARRAY; ptr to a list of such rows
+ typedef JBLOCKARRAY *JBLOCKIMAGE; ptr to a list of color component arrays
+
+The underlying type is at least a 16-bit signed integer; while "short" is big
+enough on all machines of interest, on some machines it is preferable to use
+"int" for speed reasons, despite the storage cost. Coefficients are grouped
+into 8x8 blocks (but we always use #defines DCTSIZE and DCTSIZE2 rather than
+"8" and "64").
+
+The contents of a coefficient block may be in either "natural" or zigzagged
+order, and may be true values or divided by the quantization coefficients,
+depending on where the block is in the processing pipeline. In the current
+library, coefficient blocks are kept in natural order everywhere; the entropy
+codecs zigzag or dezigzag the data as it is written or read. The blocks
+contain quantized coefficients everywhere outside the DCT/IDCT subsystems.
+(This latter decision may need to be revisited to support variable
+quantization a la JPEG Part 3.)
+
+Notice that the allocation unit is now a row of 8x8 blocks, corresponding to
+eight rows of samples. Otherwise the structure is much the same as for
+samples, and for the same reasons.
+
+On machines where malloc() can't handle a request bigger than 64Kb, this data
+structure limits us to rows of less than 512 JBLOCKs, or a picture width of
+4000+ pixels. This seems an acceptable restriction.
+
+
+On 80x86 machines, the bottom-level pointer types (JSAMPROW and JBLOCKROW)
+must be declared as "far" pointers, but the upper levels can be "near"
+(implying that the pointer lists are allocated in the DS segment).
+We use a #define symbol FAR, which expands to the "far" keyword when
+compiling on 80x86 machines and to nothing elsewhere.
+
+
+*** Suspendable processing ***
+
+In some applications it is desirable to use the JPEG library as an
+incremental, memory-to-memory filter. In this situation the data source or
+destination may be a limited-size buffer, and we can't rely on being able to
+empty or refill the buffer at arbitrary times. Instead the application would
+like to have control return from the library at buffer overflow/underrun, and
+then resume compression or decompression at a later time.
+
+This scenario is supported for simple cases. (For anything more complex, we
+recommend that the application "bite the bullet" and develop real multitasking
+capability.) The libjpeg.doc file goes into more detail about the usage and
+limitations of this capability; here we address the implications for library
+structure.
+
+The essence of the problem is that the entropy codec (coder or decoder) must
+be prepared to stop at arbitrary times. In turn, the controllers that call
+the entropy codec must be able to stop before having produced or consumed all
+the data that they normally would handle in one call. That part is reasonably
+straightforward: we make the controller call interfaces include "progress
+counters" which indicate the number of data chunks successfully processed, and
+we require callers to test the counter rather than just assume all of the data
+was processed.
+
+Rather than trying to restart at an arbitrary point, the current Huffman
+codecs are designed to restart at the beginning of the current MCU after a
+suspension due to buffer overflow/underrun. At the start of each call, the
+codec's internal state is loaded from permanent storage (in the JPEG object
+structures) into local variables. On successful completion of the MCU, the
+permanent state is updated. (This copying is not very expensive, and may even
+lead to *improved* performance if the local variables can be registerized.)
+If a suspension occurs, the codec simply returns without updating the state,
+thus effectively reverting to the start of the MCU. Note that this implies
+leaving some data unprocessed in the source/destination buffer (ie, the
+compressed partial MCU). The data source/destination module interfaces are
+specified so as to make this possible. This also implies that the data buffer
+must be large enough to hold a worst-case compressed MCU; a couple thousand
+bytes should be enough.
+
+In a successive-approximation AC refinement scan, the progressive Huffman
+decoder has to be able to undo assignments of newly nonzero coefficients if it
+suspends before the MCU is complete, since decoding requires distinguishing
+previously-zero and previously-nonzero coefficients. This is a bit tedious
+but probably won't have much effect on performance. Other variants of Huffman
+decoding need not worry about this, since they will just store the same values
+again if forced to repeat the MCU.
+
+This approach would probably not work for an arithmetic codec, since its
+modifiable state is quite large and couldn't be copied cheaply. Instead it
+would have to suspend and resume exactly at the point of the buffer end.
+
+The JPEG marker reader is designed to cope with suspension at an arbitrary
+point. It does so by backing up to the start of the marker parameter segment,
+so the data buffer must be big enough to hold the largest marker of interest.
+Again, a couple KB should be adequate. (A special "skip" convention is used
+to bypass COM and APPn markers, so these can be larger than the buffer size
+without causing problems; otherwise a 64K buffer would be needed in the worst
+case.)
+
+The JPEG marker writer currently does *not* cope with suspension. I feel that
+this is not necessary; it is much easier simply to require the application to
+ensure there is enough buffer space before starting. (An empty 2K buffer is
+more than sufficient for the header markers; and ensuring there are a dozen or
+two bytes available before calling jpeg_finish_compress() will suffice for the
+trailer.) This would not work for writing multi-scan JPEG files, but
+we simply do not intend to support that capability with suspension.
+
+
+*** Memory manager services ***
+
+The JPEG library's memory manager controls allocation and deallocation of
+memory, and it manages large "virtual" data arrays on machines where the
+operating system does not provide virtual memory. Note that the same
+memory manager serves both compression and decompression operations.
+
+In all cases, allocated objects are tied to a particular compression or
+decompression master record, and they will be released when that master
+record is destroyed.
+
+The memory manager does not provide explicit deallocation of objects.
+Instead, objects are created in "pools" of free storage, and a whole pool
+can be freed at once. This approach helps prevent storage-leak bugs, and
+it speeds up operations whenever malloc/free are slow (as they often are).
+The pools can be regarded as lifetime identifiers for objects. Two
+pools/lifetimes are defined:
+ * JPOOL_PERMANENT lasts until master record is destroyed
+ * JPOOL_IMAGE lasts until done with image (JPEG datastream)
+Permanent lifetime is used for parameters and tables that should be carried
+across from one datastream to another; this includes all application-visible
+parameters. Image lifetime is used for everything else. (A third lifetime,
+JPOOL_PASS = one processing pass, was originally planned. However it was
+dropped as not being worthwhile. The actual usage patterns are such that the
+peak memory usage would be about the same anyway; and having per-pass storage
+substantially complicates the virtual memory allocation rules --- see below.)
+
+The memory manager deals with three kinds of object:
+1. "Small" objects. Typically these require no more than 10K-20K total.
+2. "Large" objects. These may require tens to hundreds of K depending on
+ image size. Semantically they behave the same as small objects, but we
+ distinguish them for two reasons:
+ * On MS-DOS machines, large objects are referenced by FAR pointers,
+ small objects by NEAR pointers.
+ * Pool allocation heuristics may differ for large and small objects.
+ Note that individual "large" objects cannot exceed the size allowed by
+ type size_t, which may be 64K or less on some machines.
+3. "Virtual" objects. These are large 2-D arrays of JSAMPLEs or JBLOCKs
+ (typically large enough for the entire image being processed). The
+ memory manager provides stripwise access to these arrays. On machines
+ without virtual memory, the rest of the array may be swapped out to a
+ temporary file.
+
+(Note: JSAMPARRAY and JBLOCKARRAY data structures are a combination of large
+objects for the data proper and small objects for the row pointers. For
+convenience and speed, the memory manager provides single routines to create
+these structures. Similarly, virtual arrays include a small control block
+and a JSAMPARRAY or JBLOCKARRAY working buffer, all created with one call.)
+
+In the present implementation, virtual arrays are only permitted to have image
+lifespan. (Permanent lifespan would not be reasonable, and pass lifespan is
+not very useful since a virtual array's raison d'etre is to store data for
+multiple passes through the image.) We also expect that only "small" objects
+will be given permanent lifespan, though this restriction is not required by
+the memory manager.
+
+In a non-virtual-memory machine, some performance benefit can be gained by
+making the in-memory buffers for virtual arrays be as large as possible.
+(For small images, the buffers might fit entirely in memory, so blind
+swapping would be very wasteful.) The memory manager will adjust the height
+of the buffers to fit within a prespecified maximum memory usage. In order
+to do this in a reasonably optimal fashion, the manager needs to allocate all
+of the virtual arrays at once. Therefore, there isn't a one-step allocation
+routine for virtual arrays; instead, there is a "request" routine that simply
+allocates the control block, and a "realize" routine (called just once) that
+determines space allocation and creates all of the actual buffers. The
+realize routine must allow for space occupied by non-virtual large objects.
+(We don't bother to factor in the space needed for small objects, on the
+grounds that it isn't worth the trouble.)
+
+To support all this, we establish the following protocol for doing business
+with the memory manager:
+ 1. Modules must request virtual arrays (which may have only image lifespan)
+ during the initial setup phase, i.e., in their jinit_xxx routines.
+ 2. All "large" objects (including JSAMPARRAYs and JBLOCKARRAYs) must also be
+ allocated during initial setup.
+ 3. realize_virt_arrays will be called at the completion of initial setup.
+ The above conventions ensure that sufficient information is available
+ for it to choose a good size for virtual array buffers.
+Small objects of any lifespan may be allocated at any time. We expect that
+the total space used for small objects will be small enough to be negligible
+in the realize_virt_arrays computation.
+
+In a virtual-memory machine, we simply pretend that the available space is
+infinite, thus causing realize_virt_arrays to decide that it can allocate all
+the virtual arrays as full-size in-memory buffers. The overhead of the
+virtual-array access protocol is very small when no swapping occurs.
+
+A virtual array can be specified to be "pre-zeroed"; when this flag is set,
+never-yet-written sections of the array are set to zero before being made
+available to the caller. If this flag is not set, never-written sections
+of the array contain garbage. (This feature exists primarily because the
+equivalent logic would otherwise be needed in jdcoefct.c for progressive
+JPEG mode; we may as well make it available for possible other uses.)
+
+The first write pass on a virtual array is required to occur in top-to-bottom
+order; read passes, as well as any write passes after the first one, may
+access the array in any order. This restriction exists partly to simplify
+the virtual array control logic, and partly because some file systems may not
+support seeking beyond the current end-of-file in a temporary file. The main
+implication of this restriction is that rearrangement of rows (such as
+converting top-to-bottom data order to bottom-to-top) must be handled while
+reading data out of the virtual array, not while putting it in.
+
+
+*** Memory manager internal structure ***
+
+To isolate system dependencies as much as possible, we have broken the
+memory manager into two parts. There is a reasonably system-independent
+"front end" (jmemmgr.c) and a "back end" that contains only the code
+likely to change across systems. All of the memory management methods
+outlined above are implemented by the front end. The back end provides
+the following routines for use by the front end (none of these routines
+are known to the rest of the JPEG code):
+
+jpeg_mem_init, jpeg_mem_term system-dependent initialization/shutdown
+
+jpeg_get_small, jpeg_free_small interface to malloc and free library routines
+ (or their equivalents)
+
+jpeg_get_large, jpeg_free_large interface to FAR malloc/free in MSDOS machines;
+ else usually the same as
+ jpeg_get_small/jpeg_free_small
+
+jpeg_mem_available estimate available memory
+
+jpeg_open_backing_store create a backing-store object
+
+read_backing_store, manipulate a backing-store object
+write_backing_store,
+close_backing_store
+
+On some systems there will be more than one type of backing-store object
+(specifically, in MS-DOS a backing store file might be an area of extended
+memory as well as a disk file). jpeg_open_backing_store is responsible for
+choosing how to implement a given object. The read/write/close routines
+are method pointers in the structure that describes a given object; this
+lets them be different for different object types.
+
+It may be necessary to ensure that backing store objects are explicitly
+released upon abnormal program termination. For example, MS-DOS won't free
+extended memory by itself. To support this, we will expect the main program
+or surrounding application to arrange to call self_destruct (typically via
+jpeg_destroy) upon abnormal termination. This may require a SIGINT signal
+handler or equivalent. We don't want to have the back end module install its
+own signal handler, because that would pre-empt the surrounding application's
+ability to control signal handling.
+
+The IJG distribution includes several memory manager back end implementations.
+Usually the same back end should be suitable for all applications on a given
+system, but it is possible for an application to supply its own back end at
+need.
+
+
+*** Implications of DNL marker ***
+
+Some JPEG files may use a DNL marker to postpone definition of the image
+height (this would be useful for a fax-like scanner's output, for instance).
+In these files the SOF marker claims the image height is 0, and you only
+find out the true image height at the end of the first scan.
+
+We could read these files as follows:
+1. Upon seeing zero image height, replace it by 65535 (the maximum allowed).
+2. When the DNL is found, update the image height in the global image
+ descriptor.
+This implies that control modules must avoid making copies of the image
+height, and must re-test for termination after each MCU row. This would
+be easy enough to do.
+
+In cases where image-size data structures are allocated, this approach will
+result in very inefficient use of virtual memory or much-larger-than-necessary
+temporary files. This seems acceptable for something that probably won't be a
+mainstream usage. People might have to forgo use of memory-hogging options
+(such as two-pass color quantization or noninterleaved JPEG files) if they
+want efficient conversion of such files. (One could improve efficiency by
+demanding a user-supplied upper bound for the height, less than 65536; in most
+cases it could be much less.)
+
+The standard also permits the SOF marker to overestimate the image height,
+with a DNL to give the true, smaller height at the end of the first scan.
+This would solve the space problems if the overestimate wasn't too great.
+However, it implies that you don't even know whether DNL will be used.
+
+This leads to a couple of very serious objections:
+1. Testing for a DNL marker must occur in the inner loop of the decompressor's
+ Huffman decoder; this implies a speed penalty whether the feature is used
+ or not.
+2. There is no way to hide the last-minute change in image height from an
+ application using the decoder. Thus *every* application using the IJG
+ library would suffer a complexity penalty whether it cared about DNL or
+ not.
+We currently do not support DNL because of these problems.
+
+A different approach is to insist that DNL-using files be preprocessed by a
+separate program that reads ahead to the DNL, then goes back and fixes the SOF
+marker. This is a much simpler solution and is probably far more efficient.
+Even if one wants piped input, buffering the first scan of the JPEG file needs
+a lot smaller temp file than is implied by the maximum-height method. For
+this approach we'd simply treat DNL as a no-op in the decompressor (at most,
+check that it matches the SOF image height).
+
+We will not worry about making the compressor capable of outputting DNL.
+Something similar to the first scheme above could be applied if anyone ever
+wants to make that work.
*/
/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
+#include <gdcmjpeg/jinclude.h>
+#include <gdcmjpeg/jerror.h>
/* Expanded data source object for stdio input */
git://git.creatis.insa-lyon.fr / gdcm.git / commitdiff