1 /* SPMG/JPEG-LS IMPLEMENTATION V.2.1
2 =====================================
3 These programs are Copyright (c) University of British Columbia. All rights reserved.
4 They may be freely redistributed in their entirety provided that this copyright
5 notice is not removed. THEY MAY NOT BE SOLD FOR PROFIT OR INCORPORATED IN
6 COMMERCIAL PROGRAMS WITHOUT THE WRITTEN PERMISSION OF THE COPYRIGHT HOLDER.
7 Each program is provided as is, without any express or implied warranty,
8 without even the warranty of fitness for a particular purpose.
10 =========================================================
11 THIS SOFTWARE IS BASED ON HP's implementation of jpeg-ls:
12 =========================================================
14 LOCO-I/JPEG-LS IMPLEMENTATION V.0.90
15 -------------------------------------------------------------------------------
16 (c) COPYRIGHT HEWLETT-PACKARD COMPANY, 1995-1999.
17 HEWLETT-PACKARD COMPANY ("HP") DOES NOT WARRANT THE ACCURACY OR
18 COMPLETENESS OF THE INFORMATION GIVEN HERE. ANY USE MADE OF, OR
19 RELIANCE ON, SUCH INFORMATION IS ENTIRELY AT USER'S OWN RISK.
20 BY DOWNLOADING THE LOCO-I/JPEG-LS COMPRESSORS/DECOMPRESSORS
21 ("THE SOFTWARE") YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS
22 OF THIS LICENSING AGREEMENT.
23 YOU MAY DOWNLOAD AND USE THE SOFTWARE FOR NON-COMMERCIAL PURPOSES
24 FREE OF CHARGE OR FURTHER OBLIGATION. YOU MAY NOT, DIRECTLY OR
25 INDIRECTLY, DISTRIBUTE THE SOFTWARE FOR A FEE, INCORPORATE THIS
26 SOFTWARE INTO ANY PRODUCT OFFERED FOR SALE, OR USE THE SOFTWARE
27 TO PROVIDE A SERVICE FOR WHICH A FEE IS CHARGED.
28 YOU MAY MAKE COPIES OF THE SOFTWARE AND DISTRIBUTE SUCH COPIES TO
29 OTHER PERSONS PROVIDED THAT SUCH COPIES ARE ACCOMPANIED BY
30 HEWLETT-PACKARD'S COPYRIGHT NOTICE AND THIS AGREEMENT AND THAT
31 SUCH OTHER PERSONS AGREE TO BE BOUND BY THE TERMS OF THIS AGREEMENT.
32 THE SOFTWARE IS NOT OF PRODUCT QUALITY AND MAY HAVE ERRORS OR DEFECTS.
33 THE JPEG-LS STANDARD IS STILL UNDER DEVELOPMENT. THE SOFTWARE IS NOT A
34 FINAL OR FULL IMPLEMENTATION OF THE STANDARD. HP GIVES NO EXPRESS OR
35 IMPLIED WARRANTY OF ANY KIND AND ANY IMPLIED WARRANTIES OF
36 MERCHANTABILITY AND FITNESS FOR PURPOSE ARE DISCLAIMED.
37 HP SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
38 OR CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE.
39 -------------------------------------------------------------------------------
44 * Initial code by Alex Jakulin, Aug. 1995
46 * Modified and optimized: Gadiel Seroussi, October 1995
48 * Modified and added Restart marker and input tables by:
49 * David Cheng-Hsiu Chu, and Ismail R. Ismail march 1999
54 #include <string.h> /* for memset */
57 /*extern int zeroLUT[]; */ /* lookup table to find number of leading zeroes */
59 /*extern FILE *in, *out; */
61 byte negbuff[BUFSIZE+4]; /* byte I/O buffer, allowing for 4 "negative"
65 'buff' is defined as 'rawbuff+4' in bitio.h, so that buff[-4]..buff[-1]
66 are well defined. Those locations are used to "return" data to
67 the byte buffer when flushing the input bit buffer .
71 int fp; /* index into byte buffer */
72 int truebufsize; /* true size of byte buffer ( <= BUFSIZE) */
75 int zeroLUT[256]; /* table to find out number of leading zeros */
78 /* BIT I/O variables */
79 dword reg; /* BIT buffer for input/output */
80 int bits; /* number of bits free in bit buffer (on output) */
81 /* (number of bits free)-8 in bit buffer (on input)*/
84 /****************************************************************************
86 * note: some routines are implemented as preprocessor macros. See bitio.h.
87 ****************************************************************************/
90 void bufiinit(FILE *fil) {
91 /* argument is ignored */
99 byte fillinbuff(FILE *fil)
103 /* remember 4 last bytes of current buffer (for "undo") */
104 for ( i=-4; i<0; i++ )
105 buff[i] = buff[fp+i];
106 truebufsize = fread(buff, 1, BUFSIZE, fil);
107 if ( truebufsize < BUFSIZE )
109 if ( truebufsize <= 0 )
112 { /* second attempt to read past EOF */
113 fprintf(stderr,"*** Premature EOF in compressed file\n");
118 /* One attempt to read past EOF is OK */
122 /* fill buffer with zeros */
123 memset(buff+truebufsize, 0, (BUFSIZE-truebufsize)*sizeof(*buff));
131 /* Initializes the bit input routines */
139 Flush the input bit buffer TO A BYTE BOUNDARY. Return unused whole
140 bytes to the byte buffer
150 filled = 24 - bits; /* how many bits at the MS part of reg
151 have unused data. These correspond to
152 at most filled+2 bits from the input
153 stream, as at most 2 '0' bits might have
154 been dropped by marker processing */
156 dbytes = (filled+2)/8; /* the coorrect number of bytes we need to
157 "unget" is either dbytes or dbytes-1 */
158 /* this solution is more general than what is required here: it
159 will work correctly even if the end of a scan is not followed
160 by a marker, as will necessarily be the case with the standard JPEG
164 bp = buff + fp - dbytes; /* back-in the buffer */
166 for ( i=0; i<dbytes; i++ )
168 if ( bp[i-1]==0xff && (bp[i]&0x80)==0 )
170 treg |= bp[i] << (BITBUFSIZE-7-k);
175 treg |= bp[i] << (BITBUFSIZE-8-k);
183 /* check consistency */
184 if ( filled-k > 7 ) {
185 fprintf(stderr,"bitiflush: inconsistent bits=%d filled=%d k=%d\n",bits,filled,k);
189 if ( treg != (reg<<discard) ) {
190 fprintf(stderr,"bitiflush: inconsistent bits=%d discard=%d reg=%08lx treg=%08x\n",bits, discard, reg, treg);
193 if ( reg & (((1<<discard)-1)<<(BITBUFSIZE-discard)) )
194 fprintf(stderr,"bitiflush: Warning: discarding nonzero bits; reg=%08lx bits=%d discard=%d\n",reg,bits,discard);
196 fp -= dbytes; /* do the unget */
197 if ( buff[fp-1]==0xff && buff[fp]==0 ) fp++;
206 /* Unpad zeros from byte length */
225 /* creates the bit counting look-up table. */
231 for (i = 0; i < 256; ++i) {
245 /* if using functions instead of macros */
251 assert(no > 0 && no <= 18);
252 temp = reg >> (32 - no);
256 # define GETBITS(n) getbits(n)
258 /* see GETBITS(x,n) in bitio.h */