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666 lines
17 KiB
666 lines
17 KiB
/*
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* huffd.c --
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*
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* Code for JPEG lossless decoding. Large parts are grabbed from the IJG
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* software, so:
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*
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* Copyright (C) 1991, 1992, Thomas G. Lane.
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* Part of the Independent JPEG Group's software.
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* See the file Copyright for more details.
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*
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* Copyright (c) 1993 Brian C. Smith, The Regents of the University
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* of California
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* All rights reserved.
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*
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* Copyright (c) 1994 Kongji Huang and Brian C. Smith.
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* Cornell University
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* All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software and its
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* documentation for any purpose, without fee, and without written agreement is
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* hereby granted, provided that the above copyright notice and the following
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* two paragraphs appear in all copies of this software.
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*
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* IN NO EVENT SHALL CORNELL UNIVERSITY BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
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* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF CORNELL
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* UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* CORNELL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND CORNELL UNIVERSITY HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <malloc.h>
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#include "jpeg.h"
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#include "mcu.h"
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#include "io.h"
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#include "proto.h"
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#include "predictor.h"
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#define RST0 0xD0 /* RST0 marker code */
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static long getBuffer; /* current bit-extraction buffer */
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static int bitsLeft; /* # of unused bits in it */
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/*
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* The following variables keep track of the input buffer
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* for the JPEG data, which is read by ReadJpegData.
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*/
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Uchar inputBuffer[JPEG_BUF_SIZE]; /* Input buffer for JPEG data */
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int numInputBytes; /* The total number of bytes in inputBuffer */
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int maxInputBytes; /* Size of inputBuffer */
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int inputBufferOffset; /* Offset of current byte */
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/*
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* Code for extracting the next N bits from the input stream.
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* (N never exceeds 15 for JPEG data.)
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* This needs to go as fast as possible!
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*
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* We read source bytes into getBuffer and dole out bits as needed.
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* If getBuffer already contains enough bits, they are fetched in-line
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* by the macros get_bits() and get_bit(). When there aren't enough bits,
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* FillBitBuffer is called; it will attempt to fill getBuffer to the
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* "high water mark", then extract the desired number of bits. The idea,
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* of course, is to minimize the function-call overhead cost of entering
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* FillBitBuffer.
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* On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width
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* of getBuffer to be used. (On machines with wider words, an even larger
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* buffer could be used.)
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*/
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#define BITS_PER_LONG (8*sizeof(long))
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#define MIN_GET_BITS (BITS_PER_LONG-7) /* max value for long getBuffer */
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/*
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* bmask[n] is mask for n rightmost bits
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*/
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static int bmask[] = {0x0000,
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0x0001, 0x0003, 0x0007, 0x000F,
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0x001F, 0x003F, 0x007F, 0x00FF,
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0x01FF, 0x03FF, 0x07FF, 0x0FFF,
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0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF};
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/*
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*--------------------------------------------------------------
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*
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* FillBitBuffer --
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*
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* Load up the bit buffer with at least nbits
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* Process any stuffed bytes at this time.
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*
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* Results:
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* None
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*
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* Side effects:
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* The bitwise global variables are updated.
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*
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*--------------------------------------------------------------
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*/
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static void
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FillBitBuffer (nbits)
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int nbits;
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{
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int c, c2;
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while (bitsLeft < MIN_GET_BITS) {
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c = GetJpegChar ();
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/*
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* If it's 0xFF, check and discard stuffed zero byte
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*/
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if (c == 0xFF) {
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c2 = GetJpegChar ();
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if (c2 != 0) {
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/*
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* Oops, it's actually a marker indicating end of
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* compressed data. Better put it back for use later.
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*/
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UnGetJpegChar (c2);
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UnGetJpegChar (c);
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/*
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* There should be enough bits still left in the data
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* segment; if so, just break out of the while loop.
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*/
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if (bitsLeft >= nbits)
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break;
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/*
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* Uh-oh. Corrupted data: stuff zeroes into the data
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* stream, since this sometimes occurs when we are on the
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* last show_bits(8) during decoding of the Huffman
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* segment.
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*/
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c = 0;
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}
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}
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/*
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* OK, load c into getBuffer
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*/
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getBuffer = (getBuffer << 8) | c;
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bitsLeft += 8;
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}
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}
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/* Macros to make things go at some speed! */
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/* NB: parameter to get_bits should be simple variable, not expression */
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#define show_bits(nbits,rv) { \
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if (bitsLeft < nbits) FillBitBuffer(nbits); \
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rv = (getBuffer >> (bitsLeft-(nbits))) & bmask[nbits]; \
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}
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#define show_bits8(rv) { \
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if (bitsLeft < 8) FillBitBuffer(8); \
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rv = (getBuffer >> (bitsLeft-8)) & 0xff; \
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}
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#define flush_bits(nbits) { \
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bitsLeft -= (nbits); \
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}
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#define get_bits(nbits,rv) { \
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if (bitsLeft < nbits) FillBitBuffer(nbits); \
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rv = ((getBuffer >> (bitsLeft -= (nbits)))) & bmask[nbits]; \
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}
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#define get_bit(rv) { \
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if (!bitsLeft) FillBitBuffer(1); \
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rv = (getBuffer >> (--bitsLeft)) & 1; \
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}
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#ifdef DEBUG
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/*
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*--------------------------------------------------------------
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*
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* PmPutRow --
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*
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* Output one row of pixels stored in RowBuf.
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*
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* Results:
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* None
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*
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* Side effects:
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* One row of pixels are write to file pointed by outFile.
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*
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*--------------------------------------------------------------
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*/
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static void
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PmPutRow(RowBuf,numComp,numCol,Pt)
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MCU *RowBuf;
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int numCol,Pt;
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{
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register int col,v;
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/*
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* Mulitply 2^Pt before output. Pt is the point
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* transform parameter.
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*/
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if (numComp==1) { /*pgm*/
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for (col = 0; col < numCol; col++) {
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v=RowBuf[col][0]<<Pt;
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(void)putc(v,outFile);
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}
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} else { /*ppm*/
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for (col = 0; col < numCol; col++) {
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v=RowBuf[col][0]<<Pt;
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(void)putc(v,outFile);
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v=RowBuf[col][1]<<Pt;
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(void)putc(v,outFile);
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v=RowBuf[col][2]<<Pt;
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(void)putc(v,outFile);
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}
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}
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}
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#else
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/*
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*--------------------------------------------------------------
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*
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* PmPutRow --
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*
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* Output one row of pixels stored in RowBuf.
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*
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* Results:
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* None
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*
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* Side effects:
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* One row of pixels are write to file pointed by outFile.
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*
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*--------------------------------------------------------------
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*/
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#define PmPutRow(RowBuf,numComp,numCol,Pt) \
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{ register int col,v; \
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if (numComp==1) { /*pgm*/ \
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for (col = 0; col < numCol; col++) { \
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v=RowBuf[col][0]<<Pt; \
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(void)putc(v,outFile); \
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} \
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} else { /*ppm*/ \
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for (col = 0; col < numCol; col++) { \
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v=RowBuf[col][0]<<Pt; \
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(void)putc(v,outFile); \
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v=RowBuf[col][1]<<Pt; \
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(void)putc(v,outFile); \
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v=RowBuf[col][2]<<Pt; \
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(void)putc(v,outFile); \
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} \
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} \
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}
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#endif
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/*
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*--------------------------------------------------------------
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*
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* HuffDecode --
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*
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* Taken from Figure F.16: extract next coded symbol from
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* input stream. This should becode a macro.
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*
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* Results:
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* Next coded symbol
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*
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* Side effects:
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* Bitstream is parsed.
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*
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*--------------------------------------------------------------
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*/
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#define HuffDecode(htbl,rv) \
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{ \
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int l, code, temp; \
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\
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/* \
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* If the huffman code is less than 8 bits, we can use the fast \
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* table lookup to get its value. It's more than 8 bits about \
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* 3-4% of the time. \
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*/ \
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show_bits8(code); \
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if (htbl->numbits[code]) { \
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flush_bits(htbl->numbits[code]); \
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rv=htbl->value[code]; \
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} else { \
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flush_bits(8); \
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l = 8; \
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while (code > htbl->maxcode[l]) { \
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get_bit(temp); \
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code = (code << 1) | temp; \
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l++; \
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} \
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\
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/* \
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* With garbage input we may reach the sentinel value l = 17. \
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*/ \
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\
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if (l > 16) { \
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fprintf (stderr, "Corrupt JPEG data: bad Huffman code"); \
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rv = 0; /* fake a zero as the safest result */ \
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} else { \
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rv = htbl->huffval[htbl->valptr[l] + \
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((int)(code - htbl->mincode[l]))]; \
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} \
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} \
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}
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/*
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*--------------------------------------------------------------
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*
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* HuffExtend --
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*
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* Code and table for Figure F.12: extend sign bit
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*
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* Results:
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* The extended value.
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*
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* Side effects:
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* None.
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*
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*--------------------------------------------------------------
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*/
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static int extendTest[16] = /* entry n is 2**(n-1) */
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{0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
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0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000};
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static int extendOffset[16] = /* entry n is (-1 << n) + 1 */
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{0, ((-1) << 1) + 1, ((-1) << 2) + 1, ((-1) << 3) + 1, ((-1) << 4) + 1,
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((-1) << 5) + 1, ((-1) << 6) + 1, ((-1) << 7) + 1, ((-1) << 8) + 1,
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((-1) << 9) + 1, ((-1) << 10) + 1, ((-1) << 11) + 1, ((-1) << 12) + 1,
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((-1) << 13) + 1, ((-1) << 14) + 1, ((-1) << 15) + 1};
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#define HuffExtend(x,s) { \
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if ((x) < extendTest[s]) { \
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(x) += extendOffset[s]; \
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} \
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}
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/*
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*--------------------------------------------------------------
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*
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* HuffDecoderInit --
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*
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* Initialize for a Huffman-compressed scan.
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* This is invoked after reading the SOS marker.
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*
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* Results:
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* None
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*
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* Side effects:
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* None.
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*
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*--------------------------------------------------------------
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*/
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void
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HuffDecoderInit (dcPtr)
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DecompressInfo *dcPtr;
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{
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short ci;
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JpegComponentInfo *compptr;
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/*
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* Initialize static variables
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*/
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bitsLeft = 0;
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for (ci = 0; ci < dcPtr->compsInScan; ci++) {
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compptr = dcPtr->curCompInfo[ci];
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/*
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* Make sure requested tables are present
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*/
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if (dcPtr->dcHuffTblPtrs[compptr->dcTblNo] == NULL) {
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fprintf (stderr, "Error: Use of undefined Huffman table\n");
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exit (1);
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}
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/*
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* Compute derived values for Huffman tables.
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* We may do this more than once for same table, but it's not a
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* big deal
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*/
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FixHuffTbl (dcPtr->dcHuffTblPtrs[compptr->dcTblNo]);
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}
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/*
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* Initialize restart stuff
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*/
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dcPtr->restartInRows = (dcPtr->restartInterval)/(dcPtr->imageWidth);
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dcPtr->restartRowsToGo = dcPtr->restartInRows;
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dcPtr->nextRestartNum = 0;
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}
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/*
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*--------------------------------------------------------------
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*
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* ProcessRestart --
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*
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* Check for a restart marker & resynchronize decoder.
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*
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* Results:
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* None.
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*
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* Side effects:
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* BitStream is parsed, bit buffer is reset, etc.
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*
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*--------------------------------------------------------------
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*/
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static void
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ProcessRestart (dcPtr)
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DecompressInfo *dcPtr;
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{
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int c, nbytes;
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short ci;
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/*
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* Throw away any unused bits remaining in bit buffer
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*/
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nbytes = bitsLeft / 8;
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bitsLeft = 0;
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/*
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* Scan for next JPEG marker
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*/
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do {
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do { /* skip any non-FF bytes */
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nbytes++;
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c = GetJpegChar ();
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} while (c != 0xFF);
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do { /* skip any duplicate FFs */
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/*
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* we don't increment nbytes here since extra FFs are legal
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*/
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c = GetJpegChar ();
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} while (c == 0xFF);
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} while (c == 0); /* repeat if it was a stuffed FF/00 */
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if (c != (RST0 + dcPtr->nextRestartNum)) {
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/*
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* Uh-oh, the restart markers have been messed up too.
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* Just bail out.
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*/
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fprintf (stderr, "Error: Corrupt JPEG data. Exiting...\n");
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exit(-1);
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}
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/*
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* Update restart state
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*/
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dcPtr->restartRowsToGo = dcPtr->restartInRows;
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dcPtr->nextRestartNum = (dcPtr->nextRestartNum + 1) & 7;
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}
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/*
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*--------------------------------------------------------------
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*
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* DecodeFirstRow --
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*
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* Decode the first raster line of samples at the start of
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* the scan and at the beginning of each restart interval.
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* This includes modifying the component value so the real
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* value, not the difference is returned.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Bitstream is parsed.
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*
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*--------------------------------------------------------------
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*/
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void DecodeFirstRow(dcPtr,curRowBuf)
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DecompressInfo *dcPtr;
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MCU *curRowBuf;
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{
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register short curComp,ci;
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register int s,col,compsInScan,numCOL;
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register JpegComponentInfo *compptr;
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int Pr,Pt,d;
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HuffmanTable *dctbl;
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Pr=dcPtr->dataPrecision;
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Pt=dcPtr->Pt;
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compsInScan=dcPtr->compsInScan;
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numCOL=dcPtr->imageWidth;
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/*
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* the start of the scan or at the beginning of restart interval.
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*/
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for (curComp = 0; curComp < compsInScan; curComp++) {
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ci = dcPtr->MCUmembership[curComp];
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compptr = dcPtr->curCompInfo[ci];
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dctbl = dcPtr->dcHuffTblPtrs[compptr->dcTblNo];
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/*
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* Section F.2.2.1: decode the difference
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*/
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HuffDecode (dctbl,s);
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if (s) {
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get_bits(s,d);
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HuffExtend(d,s);
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} else {
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d = 0;
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}
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/*
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* Add the predictor to the difference.
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*/
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curRowBuf[0][curComp]=d+(1<<(Pr-Pt-1));
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}
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/*
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* the rest of the first row
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*/
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for (col=1; col<numCOL; col++) {
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for (curComp = 0; curComp < compsInScan; curComp++) {
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ci = dcPtr->MCUmembership[curComp];
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compptr = dcPtr->curCompInfo[ci];
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dctbl = dcPtr->dcHuffTblPtrs[compptr->dcTblNo];
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/*
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* Section F.2.2.1: decode the difference
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*/
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HuffDecode (dctbl,s);
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if (s) {
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get_bits(s,d);
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HuffExtend(d,s);
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} else {
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d = 0;
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}
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/*
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* Add the predictor to the difference.
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*/
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curRowBuf[col][curComp]=d+curRowBuf[col-1][curComp];
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}
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}
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if (dcPtr->restartInRows) {
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(dcPtr->restartRowsToGo)--;
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}
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}
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/*
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*--------------------------------------------------------------
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*
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* DecodeImage --
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*
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* Decode the input stream. This includes modifying
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* the component value so the real value, not the
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* difference is returned.
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*
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* Results:
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* None.
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*
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* 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);
|
|
}
|
|
}
|