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