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libksquirrel/kernel/kls_ljpeg/ljpeg2ppm/huffd.c

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17 KiB

/*
* huffd.c --
*
* Code for JPEG lossless decoding. Large parts are grabbed from the IJG
* software, so:
*
* Copyright (C) 1991, 1992, Thomas G. Lane.
* Part of the Independent JPEG Group's software.
* See the file Copyright for more details.
*
* Copyright (c) 1993 Brian C. Smith, The Regents of the University
* of California
* All rights reserved.
*
* Copyright (c) 1994 Kongji Huang and Brian C. Smith.
* Cornell University
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL CORNELL UNIVERSITY BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF CORNELL
* UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* CORNELL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND CORNELL UNIVERSITY HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include "jpeg.h"
#include "mcu.h"
#include "io.h"
#include "proto.h"
#include "predictor.h"
#define RST0 0xD0 /* RST0 marker code */
static long getBuffer; /* current bit-extraction buffer */
static int bitsLeft; /* # of unused bits in it */
/*
* The following variables keep track of the input buffer
* for the JPEG data, which is read by ReadJpegData.
*/
Uchar inputBuffer[JPEG_BUF_SIZE]; /* Input buffer for JPEG data */
int numInputBytes; /* The total number of bytes in inputBuffer */
int maxInputBytes; /* Size of inputBuffer */
int inputBufferOffset; /* Offset of current byte */
/*
* Code for extracting the next N bits from the input stream.
* (N never exceeds 15 for JPEG data.)
* This needs to go as fast as possible!
*
* We read source bytes into getBuffer and dole out bits as needed.
* If getBuffer already contains enough bits, they are fetched in-line
* by the macros get_bits() and get_bit(). When there aren't enough bits,
* FillBitBuffer is called; it will attempt to fill getBuffer to the
* "high water mark", then extract the desired number of bits. The idea,
* of course, is to minimize the function-call overhead cost of entering
* FillBitBuffer.
* On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width
* of getBuffer to be used. (On machines with wider words, an even larger
* buffer could be used.)
*/
#define BITS_PER_LONG (8*sizeof(long))
#define MIN_GET_BITS (BITS_PER_LONG-7) /* max value for long getBuffer */
/*
* bmask[n] is mask for n rightmost bits
*/
static int bmask[] = {0x0000,
0x0001, 0x0003, 0x0007, 0x000F,
0x001F, 0x003F, 0x007F, 0x00FF,
0x01FF, 0x03FF, 0x07FF, 0x0FFF,
0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF};
/*
*--------------------------------------------------------------
*
* FillBitBuffer --
*
* Load up the bit buffer with at least nbits
* Process any stuffed bytes at this time.
*
* Results:
* None
*
* Side effects:
* The bitwise global variables are updated.
*
*--------------------------------------------------------------
*/
static void
FillBitBuffer (nbits)
int nbits;
{
int c, c2;
while (bitsLeft < MIN_GET_BITS) {
c = GetJpegChar ();
/*
* If it's 0xFF, check and discard stuffed zero byte
*/
if (c == 0xFF) {
c2 = GetJpegChar ();
if (c2 != 0) {
/*
* Oops, it's actually a marker indicating end of
* compressed data. Better put it back for use later.
*/
UnGetJpegChar (c2);
UnGetJpegChar (c);
/*
* There should be enough bits still left in the data
* segment; if so, just break out of the while loop.
*/
if (bitsLeft >= nbits)
break;
/*
* Uh-oh. Corrupted data: stuff zeroes into the data
* stream, since this sometimes occurs when we are on the
* last show_bits(8) during decoding of the Huffman
* segment.
*/
c = 0;
}
}
/*
* OK, load c into getBuffer
*/
getBuffer = (getBuffer << 8) | c;
bitsLeft += 8;
}
}
/* Macros to make things go at some speed! */
/* NB: parameter to get_bits should be simple variable, not expression */
#define show_bits(nbits,rv) { \
if (bitsLeft < nbits) FillBitBuffer(nbits); \
rv = (getBuffer >> (bitsLeft-(nbits))) & bmask[nbits]; \
}
#define show_bits8(rv) { \
if (bitsLeft < 8) FillBitBuffer(8); \
rv = (getBuffer >> (bitsLeft-8)) & 0xff; \
}
#define flush_bits(nbits) { \
bitsLeft -= (nbits); \
}
#define get_bits(nbits,rv) { \
if (bitsLeft < nbits) FillBitBuffer(nbits); \
rv = ((getBuffer >> (bitsLeft -= (nbits)))) & bmask[nbits]; \
}
#define get_bit(rv) { \
if (!bitsLeft) FillBitBuffer(1); \
rv = (getBuffer >> (--bitsLeft)) & 1; \
}
#ifdef DEBUG
/*
*--------------------------------------------------------------
*
* PmPutRow --
*
* Output one row of pixels stored in RowBuf.
*
* Results:
* None
*
* Side effects:
* One row of pixels are write to file pointed by outFile.
*
*--------------------------------------------------------------
*/
static void
PmPutRow(RowBuf,numComp,numCol,Pt)
MCU *RowBuf;
int numCol,Pt;
{
register int col,v;
/*
* Mulitply 2^Pt before output. Pt is the point
* transform parameter.
*/
if (numComp==1) { /*pgm*/
for (col = 0; col < numCol; col++) {
v=RowBuf[col][0]<<Pt;
(void)putc(v,outFile);
}
} else { /*ppm*/
for (col = 0; col < numCol; col++) {
v=RowBuf[col][0]<<Pt;
(void)putc(v,outFile);
v=RowBuf[col][1]<<Pt;
(void)putc(v,outFile);
v=RowBuf[col][2]<<Pt;
(void)putc(v,outFile);
}
}
}
#else
/*
*--------------------------------------------------------------
*
* PmPutRow --
*
* Output one row of pixels stored in RowBuf.
*
* Results:
* None
*
* Side effects:
* One row of pixels are write to file pointed by outFile.
*
*--------------------------------------------------------------
*/
#define PmPutRow(RowBuf,numComp,numCol,Pt) \
{ register int col,v; \
if (numComp==1) { /*pgm*/ \
for (col = 0; col < numCol; col++) { \
v=RowBuf[col][0]<<Pt; \
(void)putc(v,outFile); \
} \
} else { /*ppm*/ \
for (col = 0; col < numCol; col++) { \
v=RowBuf[col][0]<<Pt; \
(void)putc(v,outFile); \
v=RowBuf[col][1]<<Pt; \
(void)putc(v,outFile); \
v=RowBuf[col][2]<<Pt; \
(void)putc(v,outFile); \
} \
} \
}
#endif
/*
*--------------------------------------------------------------
*
* HuffDecode --
*
* Taken from Figure F.16: extract next coded symbol from
* input stream. This should becode a macro.
*
* Results:
* Next coded symbol
*
* Side effects:
* Bitstream is parsed.
*
*--------------------------------------------------------------
*/
#define HuffDecode(htbl,rv) \
{ \
int l, code, temp; \
\
/* \
* If the huffman code is less than 8 bits, we can use the fast \
* table lookup to get its value. It's more than 8 bits about \
* 3-4% of the time. \
*/ \
show_bits8(code); \
if (htbl->numbits[code]) { \
flush_bits(htbl->numbits[code]); \
rv=htbl->value[code]; \
} else { \
flush_bits(8); \
l = 8; \
while (code > htbl->maxcode[l]) { \
get_bit(temp); \
code = (code << 1) | temp; \
l++; \
} \
\
/* \
* With garbage input we may reach the sentinel value l = 17. \
*/ \
\
if (l > 16) { \
fprintf (stderr, "Corrupt JPEG data: bad Huffman code"); \
rv = 0; /* fake a zero as the safest result */ \
} else { \
rv = htbl->huffval[htbl->valptr[l] + \
((int)(code - htbl->mincode[l]))]; \
} \
} \
}
/*
*--------------------------------------------------------------
*
* HuffExtend --
*
* Code and table for Figure F.12: extend sign bit
*
* Results:
* The extended value.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
static int extendTest[16] = /* entry n is 2**(n-1) */
{0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000};
static int extendOffset[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};
#define HuffExtend(x,s) { \
if ((x) < extendTest[s]) { \
(x) += extendOffset[s]; \
} \
}
/*
*--------------------------------------------------------------
*
* HuffDecoderInit --
*
* Initialize for a Huffman-compressed scan.
* This is invoked after reading the SOS marker.
*
* Results:
* None
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void
HuffDecoderInit (dcPtr)
DecompressInfo *dcPtr;
{
short ci;
JpegComponentInfo *compptr;
/*
* Initialize static variables
*/
bitsLeft = 0;
for (ci = 0; ci < dcPtr->compsInScan; ci++) {
compptr = dcPtr->curCompInfo[ci];
/*
* Make sure requested tables are present
*/
if (dcPtr->dcHuffTblPtrs[compptr->dcTblNo] == NULL) {
fprintf (stderr, "Error: Use of undefined Huffman table\n");
exit (1);
}
/*
* Compute derived values for Huffman tables.
* We may do this more than once for same table, but it's not a
* big deal
*/
FixHuffTbl (dcPtr->dcHuffTblPtrs[compptr->dcTblNo]);
}
/*
* Initialize restart stuff
*/
dcPtr->restartInRows = (dcPtr->restartInterval)/(dcPtr->imageWidth);
dcPtr->restartRowsToGo = dcPtr->restartInRows;
dcPtr->nextRestartNum = 0;
}
/*
*--------------------------------------------------------------
*
* ProcessRestart --
*
* Check for a restart marker & resynchronize decoder.
*
* Results:
* None.
*
* Side effects:
* BitStream is parsed, bit buffer is reset, etc.
*
*--------------------------------------------------------------
*/
static void
ProcessRestart (dcPtr)
DecompressInfo *dcPtr;
{
int c, nbytes;
short ci;
/*
* Throw away any unused bits remaining in bit buffer
*/
nbytes = bitsLeft / 8;
bitsLeft = 0;
/*
* Scan for next JPEG marker
*/
do {
do { /* skip any non-FF bytes */
nbytes++;
c = GetJpegChar ();
} while (c != 0xFF);
do { /* skip any duplicate FFs */
/*
* we don't increment nbytes here since extra FFs are legal
*/
c = GetJpegChar ();
} while (c == 0xFF);
} while (c == 0); /* repeat if it was a stuffed FF/00 */
if (c != (RST0 + dcPtr->nextRestartNum)) {
/*
* Uh-oh, the restart markers have been messed up too.
* Just bail out.
*/
fprintf (stderr, "Error: Corrupt JPEG data. Exiting...\n");
exit(-1);
}
/*
* Update restart state
*/
dcPtr->restartRowsToGo = dcPtr->restartInRows;
dcPtr->nextRestartNum = (dcPtr->nextRestartNum + 1) & 7;
}
/*
*--------------------------------------------------------------
*
* DecodeFirstRow --
*
* Decode the first raster line of samples at the start of
* the scan and at the beginning of each restart interval.
* This includes modifying the component value so the real
* value, not the difference is returned.
*
* Results:
* None.
*
* Side effects:
* Bitstream is parsed.
*
*--------------------------------------------------------------
*/
void DecodeFirstRow(dcPtr,curRowBuf)
DecompressInfo *dcPtr;
MCU *curRowBuf;
{
register short curComp,ci;
register int s,col,compsInScan,numCOL;
register JpegComponentInfo *compptr;
int Pr,Pt,d;
HuffmanTable *dctbl;
Pr=dcPtr->dataPrecision;
Pt=dcPtr->Pt;
compsInScan=dcPtr->compsInScan;
numCOL=dcPtr->imageWidth;
/*
* the start of the scan or at the beginning of restart interval.
*/
for (curComp = 0; curComp < compsInScan; curComp++) {
ci = dcPtr->MCUmembership[curComp];
compptr = dcPtr->curCompInfo[ci];
dctbl = dcPtr->dcHuffTblPtrs[compptr->dcTblNo];
/*
* Section F.2.2.1: decode the difference
*/
HuffDecode (dctbl,s);
if (s) {
get_bits(s,d);
HuffExtend(d,s);
} else {
d = 0;
}
/*
* Add the predictor to the difference.
*/
curRowBuf[0][curComp]=d+(1<<(Pr-Pt-1));
}
/*
* the rest of the first row
*/
for (col=1; col<numCOL; col++) {
for (curComp = 0; curComp < compsInScan; curComp++) {
ci = dcPtr->MCUmembership[curComp];
compptr = dcPtr->curCompInfo[ci];
dctbl = dcPtr->dcHuffTblPtrs[compptr->dcTblNo];
/*
* Section F.2.2.1: decode the difference
*/
HuffDecode (dctbl,s);
if (s) {
get_bits(s,d);
HuffExtend(d,s);
} else {
d = 0;
}
/*
* Add the predictor to the difference.
*/
curRowBuf[col][curComp]=d+curRowBuf[col-1][curComp];
}
}
if (dcPtr->restartInRows) {
(dcPtr->restartRowsToGo)--;
}
}
/*
*--------------------------------------------------------------
*
* DecodeImage --
*
* Decode the input stream. This includes modifying
* the component value so the real value, not the
* difference is returned.
*
* Results:
* None.
*
* Side effects:
* Bitstream is parsed.
*
*--------------------------------------------------------------
*/
void
DecodeImage(dcPtr)
DecompressInfo *dcPtr;
{
register int s,d,col,row;
register short curComp, ci;
HuffmanTable *dctbl;
JpegComponentInfo *compptr;
int predictor;
int numCOL,numROW,compsInScan;
MCU *prevRowBuf,*curRowBuf;
int imagewidth,Pt,psv;
numCOL=imagewidth=dcPtr->imageWidth;
numROW=dcPtr->imageHeight;
compsInScan=dcPtr->compsInScan;
Pt=dcPtr->Pt;
psv=dcPtr->Ss;
prevRowBuf=mcuROW2;
curRowBuf=mcuROW1;
/*
* Decode the first row of image. Output the row and
* turn this row into a previous row for later predictor
* calculation.
*/
DecodeFirstRow(dcPtr,curRowBuf);
PmPutRow(curRowBuf,compsInScan,numCOL,Pt);
swap(MCU *,prevRowBuf,curRowBuf);
for (row=1; row<numROW; row++) {
/*
* Account for restart interval, process restart marker if needed.
*/
if (dcPtr->restartInRows) {
if (dcPtr->restartRowsToGo == 0) {
ProcessRestart (dcPtr);
/*
* Reset predictors at restart.
*/
DecodeFirstRow(dcPtr,curRowBuf);
PmPutRow(curRowBuf,compsInScan,numCOL,Pt);
swap(MCU *,prevRowBuf,curRowBuf);
continue;
}
dcPtr->restartRowsToGo--;
}
/*
* The upper neighbors are predictors for the first column.
*/
for (curComp = 0; curComp < compsInScan; curComp++) {
ci = dcPtr->MCUmembership[curComp];
compptr = dcPtr->curCompInfo[ci];
dctbl = dcPtr->dcHuffTblPtrs[compptr->dcTblNo];
/*
* Section F.2.2.1: decode the difference
*/
HuffDecode (dctbl,s);
if (s) {
get_bits(s,d);
HuffExtend(d,s);
} else {
d = 0;
}
curRowBuf[0][curComp]=d+prevRowBuf[0][curComp];
}
/*
* For the rest of the column on this row, predictor
* calculations are base on PSV.
*/
for (col=1; col<numCOL; col++) {
for (curComp = 0; curComp < compsInScan; curComp++) {
ci = dcPtr->MCUmembership[curComp];
compptr = dcPtr->curCompInfo[ci];
dctbl = dcPtr->dcHuffTblPtrs[compptr->dcTblNo];
/*
* Section F.2.2.1: decode the difference
*/
HuffDecode (dctbl,s);
if (s) {
get_bits(s,d);
HuffExtend(d,s);
} else {
d = 0;
}
QuickPredict(col,curComp,curRowBuf,prevRowBuf,
psv,&predictor);
curRowBuf[col][curComp]=d+predictor;
}
}
PmPutRow(curRowBuf,compsInScan,numCOL,Pt);
swap(MCU *,prevRowBuf,curRowBuf);
}
}