src/tiff/libtiff/tif_packbits.c

   1 /* $Id$ */
   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 <stdio.h>
  35
  36 static int
  37 PackBitsPreEncode(TIFF* tif, tsample_t s)
  38 {
  39         (void) s;
  40
  41         if (!(tif->tif_data = (tidata_t)_TIFFmalloc(sizeof(tsize_t))))
  42                 return (0);
  43         /*
  44          * Calculate the scanline/tile-width size in bytes.
  45          */
  46         if (isTiled(tif))
  47                 *(tsize_t*)tif->tif_data = TIFFTileRowSize(tif);
  48         else
  49                 *(tsize_t*)tif->tif_data = TIFFScanlineSize(tif);
  50         return (1);
  51 }
  52
  53 static int
  54 PackBitsPostEncode(TIFF* tif)
  55 {
  56         if (tif->tif_data)
  57             _TIFFfree(tif->tif_data);
  58         return (1);
  59 }
  60
  61 /*
  62  * NB: tidata is the type representing *(tidata_t);
  63  *     if tidata_t is made signed then this type must
  64  *     be adjusted accordingly.
  65  */
  66 typedef unsigned char tidata;
  67
  68 /*
  69  * Encode a run of pixels.
  70  */
  71 static int
  72 PackBitsEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
  73 {
  74         unsigned char* bp = (unsigned char*) buf;
  75         tidata_t op, ep, lastliteral;
  76         long n, slop;
  77         int b;
  78         enum { BASE, LITERAL, RUN, LITERAL_RUN } state;
  79
  80         (void) s;
  81         op = tif->tif_rawcp;
  82         ep = tif->tif_rawdata + tif->tif_rawdatasize;
  83         state = BASE;
  84         lastliteral = 0;
  85         while (cc > 0) {
  86                 /*
  87                  * Find the longest string of identical bytes.
  88                  */
  89                 b = *bp++, cc--, n = 1;
  90                 for (; cc > 0 && b == *bp; cc--, bp++)
  91                         n++;
  92         again:
  93                 if (op + 2 >= ep) {             /* insure space for new data */
  94                         /*
  95                          * Be careful about writing the last
  96                          * literal.  Must write up to that point
  97                          * and then copy the remainder to the
  98                          * front of the buffer.
  99                          */
 100                         if (state == LITERAL || state == LITERAL_RUN) {
 101                                 slop = op - lastliteral;
 102                                 tif->tif_rawcc += lastliteral - tif->tif_rawcp;
 103                                 if (!TIFFFlushData1(tif))
 104                                         return (-1);
 105                                 op = tif->tif_rawcp;
 106                                 while (slop-- > 0)
 107                                         *op++ = *lastliteral++;
 108                                 lastliteral = tif->tif_rawcp;
 109                         } else {
 110                                 tif->tif_rawcc += op - tif->tif_rawcp;
 111                                 if (!TIFFFlushData1(tif))
 112                                         return (-1);
 113                                 op = tif->tif_rawcp;
 114                         }
 115                 }
 116                 switch (state) {
 117                 case BASE:              /* initial state, set run/literal */
 118                         if (n > 1) {
 119                                 state = RUN;
 120                                 if (n > 128) {
 121                                         *op++ = (tidata) -127;
 122                                         *op++ = (tidataval_t) b;
 123                                         n -= 128;
 124                                         goto again;
 125                                 }
 126                                 *op++ = (tidataval_t)(-(n-1));
 127                                 *op++ = (tidataval_t) b;
 128                         } else {
 129                                 lastliteral = op;
 130                                 *op++ = 0;
 131                                 *op++ = (tidataval_t) b;
 132                                 state = LITERAL;
 133                         }
 134                         break;
 135                 case LITERAL:           /* last object was literal string */
 136                         if (n > 1) {
 137                                 state = LITERAL_RUN;
 138                                 if (n > 128) {
 139                                         *op++ = (tidata) -127;
 140                                         *op++ = (tidataval_t) b;
 141                                         n -= 128;
 142                                         goto again;
 143                                 }
 144                                 *op++ = (tidataval_t)(-(n-1));  /* encode run */
 145                                 *op++ = (tidataval_t) b;
 146                         } else {                        /* extend literal */
 147                                 if (++(*lastliteral) == 127)
 148                                         state = BASE;
 149                                 *op++ = (tidataval_t) b;
 150                         }
 151                         break;
 152                 case RUN:               /* last object was run */
 153                         if (n > 1) {
 154                                 if (n > 128) {
 155                                         *op++ = (tidata) -127;
 156                                         *op++ = (tidataval_t) b;
 157                                         n -= 128;
 158                                         goto again;
 159                                 }
 160                                 *op++ = (tidataval_t)(-(n-1));
 161                                 *op++ = (tidataval_t) b;
 162                         } else {
 163                                 lastliteral = op;
 164                                 *op++ = 0;
 165                                 *op++ = (tidataval_t) b;
 166                                 state = LITERAL;
 167                         }
 168                         break;
 169                 case LITERAL_RUN:       /* literal followed by a run */
 170                         /*
 171                          * Check to see if previous run should
 172                          * be converted to a literal, in which
 173                          * case we convert literal-run-literal
 174                          * to a single literal.
 175                          */
 176                         if (n == 1 && op[-2] == (tidata) -1 &&
 177                             *lastliteral < 126) {
 178                                 state = (((*lastliteral) += 2) == 127 ?
 179                                     BASE : LITERAL);
 180                                 op[-2] = op[-1];        /* replicate */
 181                         } else
 182                                 state = RUN;
 183                         goto again;
 184                 }
 185         }
 186         tif->tif_rawcc += op - tif->tif_rawcp;
 187         tif->tif_rawcp = op;
 188         return (1);
 189 }
 190
 191 /*
 192  * Encode a rectangular chunk of pixels.  We break it up
 193  * into row-sized pieces to insure that encoded runs do
 194  * not span rows.  Otherwise, there can be problems with
 195  * the decoder if data is read, for example, by scanlines
 196  * when it was encoded by strips.
 197  */
 198 static int
 199 PackBitsEncodeChunk(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
 200 {
 201         tsize_t rowsize = *(tsize_t*)tif->tif_data;
 202
 203         while ((long)cc > 0) {
 204                 int     chunk = rowsize;
 205
 206                 if( cc < chunk )
 207                     chunk = cc;
 208
 209                 if (PackBitsEncode(tif, bp, chunk, s) < 0)
 210                     return (-1);
 211                 bp += chunk;
 212                 cc -= chunk;
 213         }
 214         return (1);
 215 }
 216
 217 static int
 218 PackBitsDecode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
 219 {
 220         char *bp;
 221         tsize_t cc;
 222         long n;
 223         int b;
 224
 225         (void) s;
 226         bp = (char*) tif->tif_rawcp;
 227         cc = tif->tif_rawcc;
 228         while (cc > 0 && (long)occ > 0) {
 229                 n = (long) *bp++, cc--;
 230                 /*
 231                  * Watch out for compilers that
 232                  * don't sign extend chars...
 233                  */
 234                 if (n >= 128)
 235                         n -= 256;
 236                 if (n < 0) {            /* replicate next byte -n+1 times */
 237                         if (n == -128)  /* nop */
 238                                 continue;
 239                         n = -n + 1;
 240                         if( occ < n )
 241                         {
 242                                                         TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
 243                                         "PackBitsDecode: discarding %d bytes "
 244                                         "to avoid buffer overrun",
 245                                         n - occ);
 246                             n = occ;
 247                         }
 248                         occ -= n;
 249                         b = *bp++, cc--;
 250                         while (n-- > 0)
 251                                 *op++ = (tidataval_t) b;
 252                 } else {                /* copy next n+1 bytes literally */
 253                         if (occ < n + 1)
 254                         {
 255                             TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
 256                                         "PackBitsDecode: discarding %d bytes "
 257                                         "to avoid buffer overrun",
 258                                         n - occ + 1);
 259                             n = occ - 1;
 260                         }
 261                         _TIFFmemcpy(op, bp, ++n);
 262                         op += n; occ -= n;
 263                         bp += n; cc -= n;
 264                 }
 265         }
 266         tif->tif_rawcp = (tidata_t) bp;
 267         tif->tif_rawcc = cc;
 268         if (occ > 0) {
 269                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 270                     "PackBitsDecode: Not enough data for scanline %ld",
 271                     (long) tif->tif_row);
 272                 return (0);
 273         }
 274         return (1);
 275 }
 276
 277 int
 278 TIFFInitPackBits(TIFF* tif, int scheme)
 279 {
 280         (void) scheme;
 281         tif->tif_decoderow = PackBitsDecode;
 282         tif->tif_decodestrip = PackBitsDecode;
 283         tif->tif_decodetile = PackBitsDecode;
 284         tif->tif_preencode = PackBitsPreEncode;
 285         tif->tif_postencode = PackBitsPostEncode;
 286         tif->tif_encoderow = PackBitsEncode;
 287         tif->tif_encodestrip = PackBitsEncodeChunk;
 288         tif->tif_encodetile = PackBitsEncodeChunk;
 289         return (1);
 290 }
 291 #endif /* PACKBITS_SUPPORT */
 292
 293 /* vim: set ts=8 sts=8 sw=8 noet: */