From 4caa0694570fdecca63e745c25471edc4272aad1 Mon Sep 17 00:00:00 2001 From: malaterre Date: Tue, 7 Dec 2004 15:41:59 +0000 Subject: [PATCH] ENH: Temporarily add jmemsrc. Patch suggest by Jean Michel Rouet, it enhance the jpeg lib to be able to decompress jpeg stream directly from memory + remove tabs --- src/gdcmjpeg/CMakeLists.txt | 2 +- src/gdcmjpeg/jmemsrc.c | 165 ++++++++++++++++++++++++++++++++++++ src/gdcmjpeg/jpeglib.h | 1 + 3 files changed, 167 insertions(+), 1 deletion(-) create mode 100644 src/gdcmjpeg/jmemsrc.c diff --git a/src/gdcmjpeg/CMakeLists.txt b/src/gdcmjpeg/CMakeLists.txt index 7a905f3b..43a5f275 100644 --- a/src/gdcmjpeg/CMakeLists.txt +++ b/src/gdcmjpeg/CMakeLists.txt @@ -43,7 +43,7 @@ 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 +jdatasrc.c jmemsrc.c ) SET(decomp_lossy_SRCS diff --git a/src/gdcmjpeg/jmemsrc.c b/src/gdcmjpeg/jmemsrc.c new file mode 100644 index 00000000..008592a7 --- /dev/null +++ b/src/gdcmjpeg/jmemsrc.c @@ -0,0 +1,165 @@ +/* + * jmemsrc.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 memory buffer that is preloaded with the entire + * JPEG file. This would not seem especially useful at first sight, but + * a number of people have asked for it. + * This is really just a stripped-down version of jdatasrc.c. Comparison + * of this code with jdatasrc.c may be helpful in seeing how to make + * custom source managers for other purposes. + */ + +/* 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 memory input */ + +typedef struct { + struct jpeg_source_mgr pub; /* public fields */ + + JOCTET eoi_buffer[2]; /* a place to put a dummy EOI */ +} my_source_mgr; + +typedef my_source_mgr * my_src_ptr; + + +/* + * Initialize source --- called by jpeg_read_header + * before any data is actually read. + */ + +METHODDEF(void) +init_source (j_decompress_ptr cinfo) +{ + /* No work, since jpeg_memory_src set up the buffer pointer and count. + * Indeed, if we want to read multiple JPEG images from one buffer, + * this *must* not do anything to the pointer. + */ +} + + +/* + * Fill the input buffer --- called whenever buffer is emptied. + * + * In this application, this routine should never be called; if it is called, + * the decompressor has overrun the end of the input buffer, implying we + * supplied an incomplete or corrupt JPEG datastream. A simple error exit + * might be the most appropriate response. + * + * But what we choose to do in this code is to supply dummy EOI markers + * in order to force the decompressor to finish processing and supply + * some sort of output image, no matter how corrupted. + */ + +METHODDEF(boolean) +fill_input_buffer (j_decompress_ptr cinfo) +{ + my_src_ptr src = (my_src_ptr) cinfo->src; + + WARNMS(cinfo, JWRN_JPEG_EOF); + + /* Create a fake EOI marker */ + src->eoi_buffer[0] = (JOCTET) 0xFF; + src->eoi_buffer[1] = (JOCTET) JPEG_EOI; + src->pub.next_input_byte = src->eoi_buffer; + src->pub.bytes_in_buffer = 2; + + return TRUE; +} + + +/* + * Skip data --- used to skip over a potentially large amount of + * uninteresting data (such as an APPn marker). + * + * If we overrun the end of the buffer, we let fill_input_buffer deal with + * it. An extremely large skip could cause some time-wasting here, but + * it really isn't supposed to happen ... and the decompressor will never + * skip more than 64K anyway. + */ + +METHODDEF(void) +skip_input_data (j_decompress_ptr cinfo, long num_bytes) +{ + my_src_ptr src = (my_src_ptr) cinfo->src; + + 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) +{ + /* no work necessary here */ +} + + +/* + * Prepare for input from a memory buffer. + */ + +GLOBAL(void) +jpeg_memory_src (j_decompress_ptr cinfo, const JOCTET * buffer, size_t bufsize) +{ + my_src_ptr src; + + /* The source object is made permanent so that a series of JPEG images + * can be read from a single buffer by calling jpeg_memory_src + * only before the first 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->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->pub.next_input_byte = buffer; + src->pub.bytes_in_buffer = bufsize; +} + + diff --git a/src/gdcmjpeg/jpeglib.h b/src/gdcmjpeg/jpeglib.h index 02c2d186..5d6f3a87 100644 --- a/src/gdcmjpeg/jpeglib.h +++ b/src/gdcmjpeg/jpeglib.h @@ -942,6 +942,7 @@ EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo)); /* 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)); +EXTERN(void) jpeg_memory_src JPP((j_decompress_ptr cinfo, const JOCTET * buffer, size_t bufsize)); /* Default parameter setup for compression */ EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo)); -- 2.45.2