310 lines
7.3 KiB
C
310 lines
7.3 KiB
C
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/*
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* Copyright (c) 1988-1997 Sam Leffler
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* Copyright (c) 1991-1997 Silicon Graphics, Inc.
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*
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* Permission to use, copy, modify, distribute, and sell this software and
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* its documentation for any purpose is hereby granted without fee, provided
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* that (i) the above copyright notices and this permission notice appear in
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* all copies of the software and related documentation, and (ii) the names of
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* Sam Leffler and Silicon Graphics may not be used in any advertising or
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* publicity relating to the software without the specific, prior written
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* permission of Sam Leffler and Silicon Graphics.
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*
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* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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*
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* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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* OF THIS SOFTWARE.
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*/
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#include "tiffiop.h"
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#ifdef PACKBITS_SUPPORT
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/*
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* TIFF Library.
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*
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* PackBits Compression Algorithm Support
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*/
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#include <stdio.h>
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static int
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PackBitsPreEncode(TIFF* tif, uint16 s)
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{
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(void) s;
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tif->tif_data = (uint8*)_TIFFmalloc(sizeof(tmsize_t));
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if (tif->tif_data == NULL)
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return (0);
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/*
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* Calculate the scanline/tile-width size in bytes.
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*/
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if (isTiled(tif))
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*(tmsize_t*)tif->tif_data = TIFFTileRowSize(tif);
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else
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*(tmsize_t*)tif->tif_data = TIFFScanlineSize(tif);
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return (1);
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}
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static int
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PackBitsPostEncode(TIFF* tif)
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{
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if (tif->tif_data)
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_TIFFfree(tif->tif_data);
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return (1);
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}
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/*
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* Encode a run of pixels.
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*/
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static int
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PackBitsEncode(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
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{
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unsigned char* bp = (unsigned char*) buf;
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uint8* op;
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uint8* ep;
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uint8* lastliteral;
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long n, slop;
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int b;
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enum { BASE, LITERAL, RUN, LITERAL_RUN } state;
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(void) s;
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op = tif->tif_rawcp;
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ep = tif->tif_rawdata + tif->tif_rawdatasize;
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state = BASE;
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lastliteral = 0;
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while (cc > 0) {
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/*
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* Find the longest string of identical bytes.
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*/
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b = *bp++;
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cc--;
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n = 1;
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for (; cc > 0 && b == *bp; cc--, bp++)
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n++;
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again:
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if (op + 2 >= ep) { /* insure space for new data */
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/*
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* Be careful about writing the last
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* literal. Must write up to that point
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* and then copy the remainder to the
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* front of the buffer.
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*/
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if (state == LITERAL || state == LITERAL_RUN) {
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slop = (long)(op - lastliteral);
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tif->tif_rawcc += (tmsize_t)(lastliteral - tif->tif_rawcp);
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if (!TIFFFlushData1(tif))
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return (0);
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op = tif->tif_rawcp;
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while (slop-- > 0)
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*op++ = *lastliteral++;
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lastliteral = tif->tif_rawcp;
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} else {
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tif->tif_rawcc += (tmsize_t)(op - tif->tif_rawcp);
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if (!TIFFFlushData1(tif))
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return (0);
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op = tif->tif_rawcp;
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}
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}
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switch (state) {
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case BASE: /* initial state, set run/literal */
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if (n > 1) {
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state = RUN;
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if (n > 128) {
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*op++ = (uint8) -127;
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*op++ = (uint8) b;
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n -= 128;
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goto again;
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}
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*op++ = (uint8)(-(n-1));
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*op++ = (uint8) b;
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} else {
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lastliteral = op;
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*op++ = 0;
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*op++ = (uint8) b;
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state = LITERAL;
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}
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break;
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case LITERAL: /* last object was literal string */
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if (n > 1) {
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state = LITERAL_RUN;
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if (n > 128) {
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*op++ = (uint8) -127;
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*op++ = (uint8) b;
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n -= 128;
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goto again;
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}
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*op++ = (uint8)(-(n-1)); /* encode run */
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*op++ = (uint8) b;
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} else { /* extend literal */
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if (++(*lastliteral) == 127)
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state = BASE;
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*op++ = (uint8) b;
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}
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break;
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case RUN: /* last object was run */
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if (n > 1) {
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if (n > 128) {
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*op++ = (uint8) -127;
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*op++ = (uint8) b;
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n -= 128;
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goto again;
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}
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*op++ = (uint8)(-(n-1));
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*op++ = (uint8) b;
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} else {
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lastliteral = op;
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*op++ = 0;
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*op++ = (uint8) b;
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state = LITERAL;
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}
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break;
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case LITERAL_RUN: /* literal followed by a run */
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/*
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* Check to see if previous run should
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* be converted to a literal, in which
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* case we convert literal-run-literal
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* to a single literal.
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*/
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if (n == 1 && op[-2] == (uint8) -1 &&
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*lastliteral < 126) {
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state = (((*lastliteral) += 2) == 127 ?
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BASE : LITERAL);
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op[-2] = op[-1]; /* replicate */
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} else
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state = RUN;
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goto again;
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}
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}
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tif->tif_rawcc += (tmsize_t)(op - tif->tif_rawcp);
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tif->tif_rawcp = op;
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return (1);
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}
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/*
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* Encode a rectangular chunk of pixels. We break it up
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* into row-sized pieces to insure that encoded runs do
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* not span rows. Otherwise, there can be problems with
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* the decoder if data is read, for example, by scanlines
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* when it was encoded by strips.
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*/
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static int
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PackBitsEncodeChunk(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
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{
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tmsize_t rowsize = *(tmsize_t*)tif->tif_data;
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while (cc > 0) {
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tmsize_t chunk = rowsize;
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if( cc < chunk )
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chunk = cc;
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if (PackBitsEncode(tif, bp, chunk, s) < 0)
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return (-1);
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bp += chunk;
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cc -= chunk;
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}
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return (1);
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}
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static int
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PackBitsDecode(TIFF* tif, uint8* op, tmsize_t occ, uint16 s)
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{
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static const char module[] = "PackBitsDecode";
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char *bp;
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tmsize_t cc;
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long n;
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int b;
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(void) s;
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bp = (char*) tif->tif_rawcp;
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cc = tif->tif_rawcc;
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while (cc > 0 && occ > 0) {
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n = (long) *bp++;
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cc--;
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/*
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* Watch out for compilers that
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* don't sign extend chars...
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*/
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if (n >= 128)
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n -= 256;
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if (n < 0) { /* replicate next byte -n+1 times */
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if (n == -128) /* nop */
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continue;
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n = -n + 1;
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if( occ < (tmsize_t)n )
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{
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TIFFWarningExt(tif->tif_clientdata, module,
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"Discarding %lu bytes to avoid buffer overrun",
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(unsigned long) ((tmsize_t)n - occ));
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n = (long)occ;
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}
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if( cc == 0 )
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{
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TIFFWarningExt(tif->tif_clientdata, module,
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"Terminating PackBitsDecode due to lack of data.");
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break;
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}
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occ -= n;
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b = *bp++;
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cc--;
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while (n-- > 0)
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*op++ = (uint8) b;
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} else { /* copy next n+1 bytes literally */
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if (occ < (tmsize_t)(n + 1))
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{
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TIFFWarningExt(tif->tif_clientdata, module,
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"Discarding %lu bytes to avoid buffer overrun",
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(unsigned long) ((tmsize_t)n - occ + 1));
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n = (long)occ - 1;
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}
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if (cc < (tmsize_t) (n+1))
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{
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TIFFWarningExt(tif->tif_clientdata, module,
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"Terminating PackBitsDecode due to lack of data.");
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break;
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}
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_TIFFmemcpy(op, bp, ++n);
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op += n; occ -= n;
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bp += n; cc -= n;
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}
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}
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tif->tif_rawcp = (uint8*) bp;
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tif->tif_rawcc = cc;
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if (occ > 0) {
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TIFFErrorExt(tif->tif_clientdata, module,
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"Not enough data for scanline %lu",
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(unsigned long) tif->tif_row);
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return (0);
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}
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return (1);
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}
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int
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TIFFInitPackBits(TIFF* tif, int scheme)
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{
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(void) scheme;
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tif->tif_decoderow = PackBitsDecode;
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tif->tif_decodestrip = PackBitsDecode;
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tif->tif_decodetile = PackBitsDecode;
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tif->tif_preencode = PackBitsPreEncode;
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tif->tif_postencode = PackBitsPostEncode;
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tif->tif_encoderow = PackBitsEncode;
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tif->tif_encodestrip = PackBitsEncodeChunk;
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tif->tif_encodetile = PackBitsEncodeChunk;
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return (1);
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}
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#endif /* PACKBITS_SUPPORT */
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/* vim: set ts=8 sts=8 sw=8 noet: */
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/*
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* Local Variables:
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* mode: c
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* c-basic-offset: 8
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* fill-column: 78
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* End:
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*/
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