src/tiff/libtiff/tif_read.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 /*
  28  * TIFF Library.
  29  * Scanline-oriented Read Support
  30  */
  31 #include "tiffiop.h"
  32 #include <stdio.h>
  33
  34         int TIFFFillStrip(TIFF*, tstrip_t);
  35         int TIFFFillTile(TIFF*, ttile_t);
  36 static  int TIFFStartStrip(TIFF*, tstrip_t);
  37 static  int TIFFStartTile(TIFF*, ttile_t);
  38 static  int TIFFCheckRead(TIFF*, int);
  39
  40 #define NOSTRIP ((tstrip_t) -1)                 /* undefined state */
  41 #define NOTILE  ((ttile_t) -1)                  /* undefined state */
  42
  43 /*
  44  * Seek to a random row+sample in a file.
  45  */
  46 static int
  47 TIFFSeek(TIFF* tif, uint32 row, tsample_t sample)
  48 {
  49         register TIFFDirectory *td = &tif->tif_dir;
  50         tstrip_t strip;
  51
  52         if (row >= td->td_imagelength) {        /* out of range */
  53                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "%lu: Row out of range, max %lu",
  54                     (unsigned long) row, (unsigned long) td->td_imagelength);
  55                 return (0);
  56         }
  57         if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
  58                 if (sample >= td->td_samplesperpixel) {
  59                         TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
  60                             "%lu: Sample out of range, max %lu",
  61                             (unsigned long) sample, (unsigned long) td->td_samplesperpixel);
  62                         return (0);
  63                 }
  64                 strip = sample*td->td_stripsperimage + row/td->td_rowsperstrip;
  65         } else
  66                 strip = row / td->td_rowsperstrip;
  67         if (strip != tif->tif_curstrip) {       /* different strip, refill */
  68                 if (!TIFFFillStrip(tif, strip))
  69                         return (0);
  70         } else if (row < tif->tif_row) {
  71                 /*
  72                  * Moving backwards within the same strip: backup
  73                  * to the start and then decode forward (below).
  74                  *
  75                  * NB: If you're planning on lots of random access within a
  76                  * strip, it's better to just read and decode the entire
  77                  * strip, and then access the decoded data in a random fashion.
  78                  */
  79                 if (!TIFFStartStrip(tif, strip))
  80                         return (0);
  81         }
  82         if (row != tif->tif_row) {
  83                 /*
  84                  * Seek forward to the desired row.
  85                  */
  86                 if (!(*tif->tif_seek)(tif, row - tif->tif_row))
  87                         return (0);
  88                 tif->tif_row = row;
  89         }
  90         return (1);
  91 }
  92
  93 int
  94 TIFFReadScanline(TIFF* tif, tdata_t buf, uint32 row, tsample_t sample)
  95 {
  96         int e;
  97
  98         if (!TIFFCheckRead(tif, 0))
  99                 return (-1);
 100         if( (e = TIFFSeek(tif, row, sample)) != 0) {
 101                 /*
 102                  * Decompress desired row into user buffer.
 103                  */
 104                 e = (*tif->tif_decoderow)
 105                     (tif, (tidata_t) buf, tif->tif_scanlinesize, sample);
 106
 107                 /* we are now poised at the beginning of the next row */
 108                 tif->tif_row = row + 1;
 109
 110                 if (e)
 111                         (*tif->tif_postdecode)(tif, (tidata_t) buf,
 112                             tif->tif_scanlinesize);
 113         }
 114         return (e > 0 ? 1 : -1);
 115 }
 116
 117 /*
 118  * Read a strip of data and decompress the specified
 119  * amount into the user-supplied buffer.
 120  */
 121 tsize_t
 122 TIFFReadEncodedStrip(TIFF* tif, tstrip_t strip, tdata_t buf, tsize_t size)
 123 {
 124         TIFFDirectory *td = &tif->tif_dir;
 125         uint32 nrows;
 126         tsize_t stripsize;
 127         tstrip_t sep_strip, strips_per_sep;
 128
 129         if (!TIFFCheckRead(tif, 0))
 130                 return (-1);
 131         if (strip >= td->td_nstrips) {
 132                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "%ld: Strip out of range, max %ld",
 133                     (long) strip, (long) td->td_nstrips);
 134                 return (-1);
 135         }
 136         /*
 137          * Calculate the strip size according to the number of
 138          * rows in the strip (check for truncated last strip on any
 139          * of the separations).
 140          */
 141         if( td->td_rowsperstrip >= td->td_imagelength )
 142             strips_per_sep = 1;
 143         else
 144             strips_per_sep = (td->td_imagelength+td->td_rowsperstrip-1)
 145                 / td->td_rowsperstrip;
 146
 147         sep_strip = strip % strips_per_sep;
 148
 149         if (sep_strip != strips_per_sep-1 ||
 150             (nrows = td->td_imagelength % td->td_rowsperstrip) == 0)
 151                 nrows = td->td_rowsperstrip;
 152
 153         stripsize = TIFFVStripSize(tif, nrows);
 154         if (size == (tsize_t) -1)
 155                 size = stripsize;
 156         else if (size > stripsize)
 157                 size = stripsize;
 158         if (TIFFFillStrip(tif, strip)
 159             && (*tif->tif_decodestrip)(tif, (tidata_t) buf, size,
 160                          (tsample_t)(strip / td->td_stripsperimage)) > 0 ) {
 161                 (*tif->tif_postdecode)(tif, (tidata_t) buf, size);
 162                 return (size);
 163         } else
 164                 return ((tsize_t) -1);
 165 }
 166
 167 static tsize_t
 168 TIFFReadRawStrip1(TIFF* tif,
 169     tstrip_t strip, tdata_t buf, tsize_t size, const char* module)
 170 {
 171         TIFFDirectory *td = &tif->tif_dir;
 172
 173         if (!isMapped(tif)) {
 174                 tsize_t cc;
 175
 176                 if (!SeekOK(tif, td->td_stripoffset[strip])) {
 177                         TIFFErrorExt(tif->tif_clientdata, module,
 178                             "%s: Seek error at scanline %lu, strip %lu",
 179                             tif->tif_name,
 180                             (unsigned long) tif->tif_row, (unsigned long) strip);
 181                         return (-1);
 182                 }
 183                 cc = TIFFReadFile(tif, buf, size);
 184                 if (cc != size) {
 185                         TIFFErrorExt(tif->tif_clientdata, module,
 186                 "%s: Read error at scanline %lu; got %lu bytes, expected %lu",
 187                             tif->tif_name,
 188                             (unsigned long) tif->tif_row,
 189                             (unsigned long) cc,
 190                             (unsigned long) size);
 191                         return (-1);
 192                 }
 193         } else {
 194                 if (td->td_stripoffset[strip] + size > tif->tif_size) {
 195                         TIFFErrorExt(tif->tif_clientdata, module,
 196     "%s: Read error at scanline %lu, strip %lu; got %lu bytes, expected %lu",
 197                             tif->tif_name,
 198                             (unsigned long) tif->tif_row,
 199                             (unsigned long) strip,
 200                             (unsigned long) tif->tif_size - td->td_stripoffset[strip],
 201                             (unsigned long) size);
 202                         return (-1);
 203                 }
 204                 _TIFFmemcpy(buf, tif->tif_base + td->td_stripoffset[strip],
 205                             size);
 206         }
 207         return (size);
 208 }
 209
 210 /*
 211  * Read a strip of data from the file.
 212  */
 213 tsize_t
 214 TIFFReadRawStrip(TIFF* tif, tstrip_t strip, tdata_t buf, tsize_t size)
 215 {
 216         static const char module[] = "TIFFReadRawStrip";
 217         TIFFDirectory *td = &tif->tif_dir;
 218         tsize_t bytecount;
 219
 220         if (!TIFFCheckRead(tif, 0))
 221                 return ((tsize_t) -1);
 222         if (strip >= td->td_nstrips) {
 223                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "%lu: Strip out of range, max %lu",
 224                     (unsigned long) strip, (unsigned long) td->td_nstrips);
 225                 return ((tsize_t) -1);
 226         }
 227         bytecount = td->td_stripbytecount[strip];
 228         if (bytecount <= 0) {
 229                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 230                     "%lu: Invalid strip byte count, strip %lu",
 231                     (unsigned long) bytecount, (unsigned long) strip);
 232                 return ((tsize_t) -1);
 233         }
 234         if (size != (tsize_t)-1 && size < bytecount)
 235                 bytecount = size;
 236         return (TIFFReadRawStrip1(tif, strip, buf, bytecount, module));
 237 }
 238
 239 /*
 240  * Read the specified strip and setup for decoding.
 241  * The data buffer is expanded, as necessary, to
 242  * hold the strip's data.
 243  */
 244 int
 245 TIFFFillStrip(TIFF* tif, tstrip_t strip)
 246 {
 247         static const char module[] = "TIFFFillStrip";
 248         TIFFDirectory *td = &tif->tif_dir;
 249         tsize_t bytecount;
 250
 251         bytecount = td->td_stripbytecount[strip];
 252         if (bytecount <= 0) {
 253                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 254                     "%lu: Invalid strip byte count, strip %lu",
 255                     (unsigned long) bytecount, (unsigned long) strip);
 256                 return (0);
 257         }
 258         if (isMapped(tif) &&
 259             (isFillOrder(tif, td->td_fillorder)
 260              || (tif->tif_flags & TIFF_NOBITREV))) {
 261                 /*
 262                  * The image is mapped into memory and we either don't
 263                  * need to flip bits or the compression routine is going
 264                  * to handle this operation itself.  In this case, avoid
 265                  * copying the raw data and instead just reference the
 266                  * data from the memory mapped file image.  This assumes
 267                  * that the decompression routines do not modify the
 268                  * contents of the raw data buffer (if they try to,
 269                  * the application will get a fault since the file is
 270                  * mapped read-only).
 271                  */
 272                 if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata)
 273                         _TIFFfree(tif->tif_rawdata);
 274                 tif->tif_flags &= ~TIFF_MYBUFFER;
 275                 if ( td->td_stripoffset[strip] + bytecount > tif->tif_size) {
 276                         /*
 277                          * This error message might seem strange, but it's
 278                          * what would happen if a read were done instead.
 279                          */
 280                         TIFFErrorExt(tif->tif_clientdata, module,
 281                     "%s: Read error on strip %lu; got %lu bytes, expected %lu",
 282                             tif->tif_name,
 283                             (unsigned long) strip,
 284                             (unsigned long) tif->tif_size - td->td_stripoffset[strip],
 285                             (unsigned long) bytecount);
 286                         tif->tif_curstrip = NOSTRIP;
 287                         return (0);
 288                 }
 289                 tif->tif_rawdatasize = bytecount;
 290                 tif->tif_rawdata = tif->tif_base + td->td_stripoffset[strip];
 291         } else {
 292                 /*
 293                  * Expand raw data buffer, if needed, to
 294                  * hold data strip coming from file
 295                  * (perhaps should set upper bound on
 296                  *  the size of a buffer we'll use?).
 297                  */
 298                 if (bytecount > tif->tif_rawdatasize) {
 299                         tif->tif_curstrip = NOSTRIP;
 300                         if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
 301                                 TIFFErrorExt(tif->tif_clientdata, module,
 302                                 "%s: Data buffer too small to hold strip %lu",
 303                                     tif->tif_name, (unsigned long) strip);
 304                                 return (0);
 305                         }
 306                         if (!TIFFReadBufferSetup(tif, 0,
 307                             TIFFroundup(bytecount, 1024)))
 308                                 return (0);
 309                 }
 310                 if (TIFFReadRawStrip1(tif, strip, (unsigned char *)tif->tif_rawdata,
 311                     bytecount, module) != bytecount)
 312                         return (0);
 313                 if (!isFillOrder(tif, td->td_fillorder) &&
 314                     (tif->tif_flags & TIFF_NOBITREV) == 0)
 315                         TIFFReverseBits(tif->tif_rawdata, bytecount);
 316         }
 317         return (TIFFStartStrip(tif, strip));
 318 }
 319
 320 /*
 321  * Tile-oriented Read Support
 322  * Contributed by Nancy Cam (Silicon Graphics).
 323  */
 324
 325 /*
 326  * Read and decompress a tile of data.  The
 327  * tile is selected by the (x,y,z,s) coordinates.
 328  */
 329 tsize_t
 330 TIFFReadTile(TIFF* tif,
 331     tdata_t buf, uint32 x, uint32 y, uint32 z, tsample_t s)
 332 {
 333         if (!TIFFCheckRead(tif, 1) || !TIFFCheckTile(tif, x, y, z, s))
 334                 return (-1);
 335         return (TIFFReadEncodedTile(tif,
 336             TIFFComputeTile(tif, x, y, z, s), buf, (tsize_t) -1));
 337 }
 338
 339 /*
 340  * Read a tile of data and decompress the specified
 341  * amount into the user-supplied buffer.
 342  */
 343 tsize_t
 344 TIFFReadEncodedTile(TIFF* tif, ttile_t tile, tdata_t buf, tsize_t size)
 345 {
 346         TIFFDirectory *td = &tif->tif_dir;
 347         tsize_t tilesize = tif->tif_tilesize;
 348
 349         if (!TIFFCheckRead(tif, 1))
 350                 return (-1);
 351         if (tile >= td->td_nstrips) {
 352                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "%ld: Tile out of range, max %ld",
 353                     (long) tile, (unsigned long) td->td_nstrips);
 354                 return (-1);
 355         }
 356         if (size == (tsize_t) -1)
 357                 size = tilesize;
 358         else if (size > tilesize)
 359                 size = tilesize;
 360         if (TIFFFillTile(tif, tile) && (*tif->tif_decodetile)(tif,
 361             (tidata_t) buf, size, (tsample_t)(tile/td->td_stripsperimage))) {
 362                 (*tif->tif_postdecode)(tif, (tidata_t) buf, size);
 363                 return (size);
 364         } else
 365                 return (-1);
 366 }
 367
 368 static tsize_t
 369 TIFFReadRawTile1(TIFF* tif,
 370     ttile_t tile, tdata_t buf, tsize_t size, const char* module)
 371 {
 372         TIFFDirectory *td = &tif->tif_dir;
 373
 374         if (!isMapped(tif)) {
 375                 tsize_t cc;
 376
 377                 if (!SeekOK(tif, td->td_stripoffset[tile])) {
 378                         TIFFErrorExt(tif->tif_clientdata, module,
 379                             "%s: Seek error at row %ld, col %ld, tile %ld",
 380                             tif->tif_name,
 381                             (long) tif->tif_row,
 382                             (long) tif->tif_col,
 383                             (long) tile);
 384                         return ((tsize_t) -1);
 385                 }
 386                 cc = TIFFReadFile(tif, buf, size);
 387                 if (cc != size) {
 388                         TIFFErrorExt(tif->tif_clientdata, module,
 389             "%s: Read error at row %ld, col %ld; got %lu bytes, expected %lu",
 390                             tif->tif_name,
 391                             (long) tif->tif_row,
 392                             (long) tif->tif_col,
 393                             (unsigned long) cc,
 394                             (unsigned long) size);
 395                         return ((tsize_t) -1);
 396                 }
 397         } else {
 398                 if (td->td_stripoffset[tile] + size > tif->tif_size) {
 399                         TIFFErrorExt(tif->tif_clientdata, module,
 400     "%s: Read error at row %ld, col %ld, tile %ld; got %lu bytes, expected %lu",
 401                             tif->tif_name,
 402                             (long) tif->tif_row,
 403                             (long) tif->tif_col,
 404                             (long) tile,
 405                             (unsigned long) tif->tif_size - td->td_stripoffset[tile],
 406                             (unsigned long) size);
 407                         return ((tsize_t) -1);
 408                 }
 409                 _TIFFmemcpy(buf, tif->tif_base + td->td_stripoffset[tile], size);
 410         }
 411         return (size);
 412 }
 413
 414 /*
 415  * Read a tile of data from the file.
 416  */
 417 tsize_t
 418 TIFFReadRawTile(TIFF* tif, ttile_t tile, tdata_t buf, tsize_t size)
 419 {
 420         static const char module[] = "TIFFReadRawTile";
 421         TIFFDirectory *td = &tif->tif_dir;
 422         tsize_t bytecount;
 423
 424         if (!TIFFCheckRead(tif, 1))
 425                 return ((tsize_t) -1);
 426         if (tile >= td->td_nstrips) {
 427                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "%lu: Tile out of range, max %lu",
 428                     (unsigned long) tile, (unsigned long) td->td_nstrips);
 429                 return ((tsize_t) -1);
 430         }
 431         bytecount = td->td_stripbytecount[tile];
 432         if (size != (tsize_t) -1 && size < bytecount)
 433                 bytecount = size;
 434         return (TIFFReadRawTile1(tif, tile, buf, bytecount, module));
 435 }
 436
 437 /*
 438  * Read the specified tile and setup for decoding.
 439  * The data buffer is expanded, as necessary, to
 440  * hold the tile's data.
 441  */
 442 int
 443 TIFFFillTile(TIFF* tif, ttile_t tile)
 444 {
 445         static const char module[] = "TIFFFillTile";
 446         TIFFDirectory *td = &tif->tif_dir;
 447         tsize_t bytecount;
 448
 449         bytecount = td->td_stripbytecount[tile];
 450         if (bytecount <= 0) {
 451                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 452                     "%lu: Invalid tile byte count, tile %lu",
 453                     (unsigned long) bytecount, (unsigned long) tile);
 454                 return (0);
 455         }
 456         if (isMapped(tif) &&
 457             (isFillOrder(tif, td->td_fillorder)
 458              || (tif->tif_flags & TIFF_NOBITREV))) {
 459                 /*
 460                  * The image is mapped into memory and we either don't
 461                  * need to flip bits or the compression routine is going
 462                  * to handle this operation itself.  In this case, avoid
 463                  * copying the raw data and instead just reference the
 464                  * data from the memory mapped file image.  This assumes
 465                  * that the decompression routines do not modify the
 466                  * contents of the raw data buffer (if they try to,
 467                  * the application will get a fault since the file is
 468                  * mapped read-only).
 469                  */
 470                 if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata)
 471                         _TIFFfree(tif->tif_rawdata);
 472                 tif->tif_flags &= ~TIFF_MYBUFFER;
 473                 if ( td->td_stripoffset[tile] + bytecount > tif->tif_size) {
 474                         tif->tif_curtile = NOTILE;
 475                         return (0);
 476                 }
 477                 tif->tif_rawdatasize = bytecount;
 478                 tif->tif_rawdata = tif->tif_base + td->td_stripoffset[tile];
 479         } else {
 480                 /*
 481                  * Expand raw data buffer, if needed, to
 482                  * hold data tile coming from file
 483                  * (perhaps should set upper bound on
 484                  *  the size of a buffer we'll use?).
 485                  */
 486                 if (bytecount > tif->tif_rawdatasize) {
 487                         tif->tif_curtile = NOTILE;
 488                         if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
 489                                 TIFFErrorExt(tif->tif_clientdata, module,
 490                                 "%s: Data buffer too small to hold tile %ld",
 491                                     tif->tif_name, (long) tile);
 492                                 return (0);
 493                         }
 494                         if (!TIFFReadBufferSetup(tif, 0,
 495                             TIFFroundup(bytecount, 1024)))
 496                                 return (0);
 497                 }
 498                 if (TIFFReadRawTile1(tif, tile,
 499                                      (unsigned char *)tif->tif_rawdata,
 500                                      bytecount, module) != bytecount)
 501                         return (0);
 502                 if (!isFillOrder(tif, td->td_fillorder) &&
 503                     (tif->tif_flags & TIFF_NOBITREV) == 0)
 504                         TIFFReverseBits(tif->tif_rawdata, bytecount);
 505         }
 506         return (TIFFStartTile(tif, tile));
 507 }
 508
 509 /*
 510  * Setup the raw data buffer in preparation for
 511  * reading a strip of raw data.  If the buffer
 512  * is specified as zero, then a buffer of appropriate
 513  * size is allocated by the library.  Otherwise,
 514  * the client must guarantee that the buffer is
 515  * large enough to hold any individual strip of
 516  * raw data.
 517  */
 518 int
 519 TIFFReadBufferSetup(TIFF* tif, tdata_t bp, tsize_t size)
 520 {
 521         static const char module[] = "TIFFReadBufferSetup";
 522
 523         if (tif->tif_rawdata) {
 524                 if (tif->tif_flags & TIFF_MYBUFFER)
 525                         _TIFFfree(tif->tif_rawdata);
 526                 tif->tif_rawdata = NULL;
 527         }
 528         if (bp) {
 529                 tif->tif_rawdatasize = size;
 530                 tif->tif_rawdata = (tidata_t) bp;
 531                 tif->tif_flags &= ~TIFF_MYBUFFER;
 532         } else {
 533                 tif->tif_rawdatasize = TIFFroundup(size, 1024);
 534                 tif->tif_rawdata = (tidata_t) _TIFFmalloc(tif->tif_rawdatasize);
 535                 tif->tif_flags |= TIFF_MYBUFFER;
 536         }
 537         if (tif->tif_rawdata == NULL) {
 538                 TIFFErrorExt(tif->tif_clientdata, module,
 539                     "%s: No space for data buffer at scanline %ld",
 540                     tif->tif_name, (long) tif->tif_row);
 541                 tif->tif_rawdatasize = 0;
 542                 return (0);
 543         }
 544         return (1);
 545 }
 546
 547 /*
 548  * Set state to appear as if a
 549  * strip has just been read in.
 550  */
 551 static int
 552 TIFFStartStrip(TIFF* tif, tstrip_t strip)
 553 {
 554         TIFFDirectory *td = &tif->tif_dir;
 555
 556         if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
 557                 if (!(*tif->tif_setupdecode)(tif))
 558                         return (0);
 559                 tif->tif_flags |= TIFF_CODERSETUP;
 560         }
 561         tif->tif_curstrip = strip;
 562         tif->tif_row = (strip % td->td_stripsperimage) * td->td_rowsperstrip;
 563         tif->tif_rawcp = tif->tif_rawdata;
 564         tif->tif_rawcc = td->td_stripbytecount[strip];
 565         return ((*tif->tif_predecode)(tif,
 566                         (tsample_t)(strip / td->td_stripsperimage)));
 567 }
 568
 569 /*
 570  * Set state to appear as if a
 571  * tile has just been read in.
 572  */
 573 static int
 574 TIFFStartTile(TIFF* tif, ttile_t tile)
 575 {
 576         TIFFDirectory *td = &tif->tif_dir;
 577
 578         if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
 579                 if (!(*tif->tif_setupdecode)(tif))
 580                         return (0);
 581                 tif->tif_flags |= TIFF_CODERSETUP;
 582         }
 583         tif->tif_curtile = tile;
 584         tif->tif_row =
 585             (tile % TIFFhowmany(td->td_imagewidth, td->td_tilewidth)) *
 586                 td->td_tilelength;
 587         tif->tif_col =
 588             (tile % TIFFhowmany(td->td_imagelength, td->td_tilelength)) *
 589                 td->td_tilewidth;
 590         tif->tif_rawcp = tif->tif_rawdata;
 591         tif->tif_rawcc = td->td_stripbytecount[tile];
 592         return ((*tif->tif_predecode)(tif,
 593                         (tsample_t)(tile/td->td_stripsperimage)));
 594 }
 595
 596 static int
 597 TIFFCheckRead(TIFF* tif, int tiles)
 598 {
 599         if (tif->tif_mode == O_WRONLY) {
 600                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "File not open for reading");
 601                 return (0);
 602         }
 603         if (tiles ^ isTiled(tif)) {
 604                 TIFFErrorExt(tif->tif_clientdata, tif->tif_name, tiles ?
 605                     "Can not read tiles from a stripped image" :
 606                     "Can not read scanlines from a tiled image");
 607                 return (0);
 608         }
 609         return (1);
 610 }
 611
 612 void
 613 _TIFFNoPostDecode(TIFF* tif, tidata_t buf, tsize_t cc)
 614 {
 615     (void) tif; (void) buf; (void) cc;
 616 }
 617
 618 void
 619 _TIFFSwab16BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 620 {
 621     (void) tif;
 622     assert((cc & 1) == 0);
 623     TIFFSwabArrayOfShort((uint16*) buf, cc/2);
 624 }
 625
 626 void
 627 _TIFFSwab24BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 628 {
 629     (void) tif;
 630     assert((cc % 3) == 0);
 631     TIFFSwabArrayOfTriples((uint8*) buf, cc/3);
 632 }
 633
 634 void
 635 _TIFFSwab32BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 636 {
 637     (void) tif;
 638     assert((cc & 3) == 0);
 639     TIFFSwabArrayOfLong((uint32*) buf, cc/4);
 640 }
 641
 642 void
 643 _TIFFSwab64BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 644 {
 645     (void) tif;
 646     assert((cc & 7) == 0);
 647     TIFFSwabArrayOfDouble((double*) buf, cc/8);
 648 }
 649
 650 /* vim: set ts=8 sts=8 sw=8 noet: */