| 1 | /* $Id: tif_packbits.c,v 1.13 2006/02/07 11:03:29 dron Exp $ */
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| 2 |
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| 3 | /*
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| 4 | * Copyright (c) 1988-1997 Sam Leffler
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| 5 | * Copyright (c) 1991-1997 Silicon Graphics, Inc.
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| 6 | *
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| 7 | * Permission to use, copy, modify, distribute, and sell this software and
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| 8 | * its documentation for any purpose is hereby granted without fee, provided
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| 9 | * that (i) the above copyright notices and this permission notice appear in
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| 10 | * all copies of the software and related documentation, and (ii) the names of
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| 11 | * Sam Leffler and Silicon Graphics may not be used in any advertising or
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| 12 | * publicity relating to the software without the specific, prior written
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| 13 | * permission of Sam Leffler and Silicon Graphics.
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| 14 | *
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| 15 | * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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| 16 | * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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| 17 | * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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| 18 | *
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| 19 | * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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| 20 | * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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| 21 | * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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| 22 | * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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| 23 | * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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| 24 | * OF THIS SOFTWARE.
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| 25 | */
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| 26 |
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| 27 | #include "tiffiop.h"
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| 28 | #ifdef PACKBITS_SUPPORT
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| 29 | /*
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| 30 | * TIFF Library.
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| 31 | *
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| 32 | * PackBits Compression Algorithm Support
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| 33 | */
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| 34 | #include <stdio.h>
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| 35 |
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| 36 | static int
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| 37 | PackBitsPreEncode(TIFF* tif, tsample_t s)
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| 38 | {
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| 39 | (void) s;
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| 40 |
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| 41 | if (!(tif->tif_data = (tidata_t)_TIFFmalloc(sizeof(tsize_t))))
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| 42 | return (0);
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| 43 | /*
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| 44 | * Calculate the scanline/tile-width size in bytes.
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| 45 | */
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| 46 | if (isTiled(tif))
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| 47 | *(tsize_t*)tif->tif_data = TIFFTileRowSize(tif);
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| 48 | else
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| 49 | *(tsize_t*)tif->tif_data = TIFFScanlineSize(tif);
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| 50 | return (1);
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| 51 | }
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| 52 |
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| 53 | static int
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| 54 | PackBitsPostEncode(TIFF* tif)
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| 55 | {
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| 56 | if (tif->tif_data)
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| 57 | _TIFFfree(tif->tif_data);
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| 58 | return (1);
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| 59 | }
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| 60 |
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| 61 | /*
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| 62 | * NB: tidata is the type representing *(tidata_t);
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| 63 | * if tidata_t is made signed then this type must
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| 64 | * be adjusted accordingly.
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| 65 | */
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| 66 | typedef unsigned char tidata;
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| 67 |
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| 68 | /*
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| 69 | * Encode a run of pixels.
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| 70 | */
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| 71 | static int
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| 72 | PackBitsEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
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| 73 | {
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| 74 | unsigned char* bp = (unsigned char*) buf;
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| 75 | tidata_t op, ep, lastliteral;
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| 76 | long n, slop;
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| 77 | int b;
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| 78 | enum { BASE, LITERAL, RUN, LITERAL_RUN } state;
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| 79 |
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| 80 | (void) s;
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| 81 | op = tif->tif_rawcp;
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| 82 | ep = tif->tif_rawdata + tif->tif_rawdatasize;
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| 83 | state = BASE;
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| 84 | lastliteral = 0;
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| 85 | while (cc > 0) {
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| 86 | /*
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| 87 | * Find the longest string of identical bytes.
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| 88 | */
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| 89 | b = *bp++, cc--, n = 1;
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| 90 | for (; cc > 0 && b == *bp; cc--, bp++)
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| 91 | n++;
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| 92 | again:
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| 93 | if (op + 2 >= ep) { /* insure space for new data */
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| 94 | /*
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| 95 | * Be careful about writing the last
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| 96 | * literal. Must write up to that point
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| 97 | * and then copy the remainder to the
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| 98 | * front of the buffer.
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| 99 | */
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| 100 | if (state == LITERAL || state == LITERAL_RUN) {
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| 101 | slop = op - lastliteral;
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| 102 | tif->tif_rawcc += lastliteral - tif->tif_rawcp;
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| 103 | if (!TIFFFlushData1(tif))
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| 104 | return (-1);
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| 105 | op = tif->tif_rawcp;
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| 106 | while (slop-- > 0)
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| 107 | *op++ = *lastliteral++;
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| 108 | lastliteral = tif->tif_rawcp;
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| 109 | } else {
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| 110 | tif->tif_rawcc += op - tif->tif_rawcp;
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| 111 | if (!TIFFFlushData1(tif))
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| 112 | return (-1);
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| 113 | op = tif->tif_rawcp;
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| 114 | }
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| 115 | }
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| 116 | switch (state) {
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| 117 | case BASE: /* initial state, set run/literal */
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| 118 | if (n > 1) {
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| 119 | state = RUN;
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| 120 | if (n > 128) {
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| 121 | *op++ = (tidata) -127;
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| 122 | *op++ = (tidataval_t) b;
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| 123 | n -= 128;
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| 124 | goto again;
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| 125 | }
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| 126 | *op++ = (tidataval_t)(-(n-1));
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| 127 | *op++ = (tidataval_t) b;
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| 128 | } else {
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| 129 | lastliteral = op;
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| 130 | *op++ = 0;
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| 131 | *op++ = (tidataval_t) b;
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| 132 | state = LITERAL;
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| 133 | }
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| 134 | break;
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| 135 | case LITERAL: /* last object was literal string */
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| 136 | if (n > 1) {
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| 137 | state = LITERAL_RUN;
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| 138 | if (n > 128) {
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| 139 | *op++ = (tidata) -127;
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| 140 | *op++ = (tidataval_t) b;
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| 141 | n -= 128;
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| 142 | goto again;
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| 143 | }
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| 144 | *op++ = (tidataval_t)(-(n-1)); /* encode run */
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| 145 | *op++ = (tidataval_t) b;
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| 146 | } else { /* extend literal */
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| 147 | if (++(*lastliteral) == 127)
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| 148 | state = BASE;
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| 149 | *op++ = (tidataval_t) b;
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| 150 | }
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| 151 | break;
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| 152 | case RUN: /* last object was run */
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| 153 | if (n > 1) {
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| 154 | if (n > 128) {
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| 155 | *op++ = (tidata) -127;
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| 156 | *op++ = (tidataval_t) b;
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| 157 | n -= 128;
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| 158 | goto again;
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| 159 | }
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| 160 | *op++ = (tidataval_t)(-(n-1));
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| 161 | *op++ = (tidataval_t) b;
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| 162 | } else {
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| 163 | lastliteral = op;
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| 164 | *op++ = 0;
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| 165 | *op++ = (tidataval_t) b;
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| 166 | state = LITERAL;
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| 167 | }
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| 168 | break;
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| 169 | case LITERAL_RUN: /* literal followed by a run */
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| 170 | /*
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| 171 | * Check to see if previous run should
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| 172 | * be converted to a literal, in which
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| 173 | * case we convert literal-run-literal
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| 174 | * to a single literal.
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| 175 | */
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| 176 | if (n == 1 && op[-2] == (tidata) -1 &&
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| 177 | *lastliteral < 126) {
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| 178 | state = (((*lastliteral) += 2) == 127 ?
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| 179 | BASE : LITERAL);
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| 180 | op[-2] = op[-1]; /* replicate */
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| 181 | } else
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| 182 | state = RUN;
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| 183 | goto again;
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| 184 | }
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| 185 | }
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| 186 | tif->tif_rawcc += op - tif->tif_rawcp;
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| 187 | tif->tif_rawcp = op;
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| 188 | return (1);
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| 189 | }
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| 190 |
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| 191 | /*
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| 192 | * Encode a rectangular chunk of pixels. We break it up
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| 193 | * into row-sized pieces to insure that encoded runs do
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| 194 | * not span rows. Otherwise, there can be problems with
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| 195 | * the decoder if data is read, for example, by scanlines
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| 196 | * when it was encoded by strips.
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| 197 | */
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| 198 | static int
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| 199 | PackBitsEncodeChunk(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
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| 200 | {
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| 201 | tsize_t rowsize = *(tsize_t*)tif->tif_data;
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| 202 |
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| 203 | while ((long)cc > 0) {
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| 204 | int chunk = rowsize;
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| 205 |
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| 206 | if( cc < chunk )
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| 207 | chunk = cc;
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| 208 |
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| 209 | if (PackBitsEncode(tif, bp, chunk, s) < 0)
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| 210 | return (-1);
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| 211 | bp += chunk;
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| 212 | cc -= chunk;
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| 213 | }
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| 214 | return (1);
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| 215 | }
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| 216 |
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| 217 | static int
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| 218 | PackBitsDecode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
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| 219 | {
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| 220 | char *bp;
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| 221 | tsize_t cc;
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| 222 | long n;
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| 223 | int b;
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| 224 |
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| 225 | (void) s;
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| 226 | bp = (char*) tif->tif_rawcp;
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| 227 | cc = tif->tif_rawcc;
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| 228 | while (cc > 0 && (long)occ > 0) {
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| 229 | n = (long) *bp++, cc--;
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| 230 | /*
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| 231 | * Watch out for compilers that
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| 232 | * don't sign extend chars...
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| 233 | */
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| 234 | if (n >= 128)
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| 235 | n -= 256;
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| 236 | if (n < 0) { /* replicate next byte -n+1 times */
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| 237 | if (n == -128) /* nop */
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| 238 | continue;
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| 239 | n = -n + 1;
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| 240 | if( occ < n )
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| 241 | {
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| 242 | TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
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| 243 | "PackBitsDecode: discarding %d bytes "
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| 244 | "to avoid buffer overrun",
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| 245 | n - occ);
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| 246 | n = occ;
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| 247 | }
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| 248 | occ -= n;
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| 249 | b = *bp++, cc--;
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| 250 | while (n-- > 0)
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| 251 | *op++ = (tidataval_t) b;
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| 252 | } else { /* copy next n+1 bytes literally */
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| 253 | if (occ < n + 1)
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| 254 | {
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| 255 | TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
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| 256 | "PackBitsDecode: discarding %d bytes "
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| 257 | "to avoid buffer overrun",
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| 258 | n - occ + 1);
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| 259 | n = occ - 1;
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| 260 | }
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| 261 | _TIFFmemcpy(op, bp, ++n);
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| 262 | op += n; occ -= n;
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| 263 | bp += n; cc -= n;
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| 264 | }
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| 265 | }
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| 266 | tif->tif_rawcp = (tidata_t) bp;
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| 267 | tif->tif_rawcc = cc;
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| 268 | if (occ > 0) {
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| 269 | TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
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| 270 | "PackBitsDecode: Not enough data for scanline %ld",
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| 271 | (long) tif->tif_row);
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| 272 | return (0);
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| 273 | }
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| 274 | return (1);
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| 275 | }
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| 276 |
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| 277 | int
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| 278 | TIFFInitPackBits(TIFF* tif, int scheme)
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| 279 | {
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| 280 | (void) scheme;
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| 281 | tif->tif_decoderow = PackBitsDecode;
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| 282 | tif->tif_decodestrip = PackBitsDecode;
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| 283 | tif->tif_decodetile = PackBitsDecode;
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| 284 | tif->tif_preencode = PackBitsPreEncode;
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| 285 | tif->tif_postencode = PackBitsPostEncode;
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| 286 | tif->tif_encoderow = PackBitsEncode;
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| 287 | tif->tif_encodestrip = PackBitsEncodeChunk;
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| 288 | tif->tif_encodetile = PackBitsEncodeChunk;
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| 289 | return (1);
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| 290 | }
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| 291 | #endif /* PACKBITS_SUPPORT */
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| 292 |
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| 293 | /* vim: set ts=8 sts=8 sw=8 noet: */
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