compiler/libpng/pngread.c

   1
   2 /* pngread.c - read a PNG file
   3  *
   4  * Last changed in libpng 1.5.1 [$RDATE%]
   5  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
   6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   8  *
   9  * This code is released under the libpng license.
  10  * For conditions of distribution and use, see the disclaimer
  11  * and license in png.h
  12  *
  13  * This file contains routines that an application calls directly to
  14  * read a PNG file or stream.
  15  */
  16
  17 #include "pngpriv.h"
  18
  19 #ifdef PNG_READ_SUPPORTED
  20
  21 /* Create a PNG structure for reading, and allocate any memory needed. */
  22 PNG_FUNCTION(png_structp,PNGAPI
  23 png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
  24     png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
  25 {
  26
  27 #ifdef PNG_USER_MEM_SUPPORTED
  28    return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
  29        warn_fn, NULL, NULL, NULL));
  30 }
  31
  32 /* Alternate create PNG structure for reading, and allocate any memory
  33  * needed.
  34  */
  35 PNG_FUNCTION(png_structp,PNGAPI
  36 png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
  37     png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
  38     png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
  39 {
  40 #endif /* PNG_USER_MEM_SUPPORTED */
  41
  42 #ifdef PNG_SETJMP_SUPPORTED
  43    volatile
  44 #endif
  45    png_structp png_ptr;
  46    volatile int png_cleanup_needed = 0;
  47
  48 #ifdef PNG_SETJMP_SUPPORTED
  49 #ifdef USE_FAR_KEYWORD
  50    jmp_buf png_jmpbuf;
  51 #endif
  52 #endif
  53
  54    int i;
  55
  56    png_debug(1, "in png_create_read_struct");
  57
  58 #ifdef PNG_USER_MEM_SUPPORTED
  59    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
  60        malloc_fn, mem_ptr);
  61 #else
  62    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
  63 #endif
  64    if (png_ptr == NULL)
  65       return (NULL);
  66
  67    /* Added at libpng-1.2.6 */
  68 #ifdef PNG_USER_LIMITS_SUPPORTED
  69    png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
  70    png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
  71
  72 #  ifdef PNG_USER_CHUNK_CACHE_MAX
  73    /* Added at libpng-1.2.43 and 1.4.0 */
  74    png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
  75 #  endif
  76
  77 #  ifdef PNG_SET_USER_CHUNK_MALLOC_MAX
  78    /* Added at libpng-1.2.43 and 1.4.1 */
  79    png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
  80 #  endif
  81 #endif
  82
  83 #ifdef PNG_SETJMP_SUPPORTED
  84 /* Applications that neglect to set up their own setjmp() and then
  85    encounter a png_error() will longjmp here.  Since the jmpbuf is
  86    then meaningless we abort instead of returning. */
  87 #ifdef USE_FAR_KEYWORD
  88    if (setjmp(png_jmpbuf))
  89 #else
  90    if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
  91 #endif
  92       PNG_ABORT();
  93 #ifdef USE_FAR_KEYWORD
  94    png_memcpy(png_jmpbuf(png_ptr), png_jmpbuf, png_sizeof(jmp_buf));
  95 #endif
  96 #endif /* PNG_SETJMP_SUPPORTED */
  97
  98 #ifdef PNG_USER_MEM_SUPPORTED
  99    png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
 100 #endif
 101
 102    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
 103
 104    if (user_png_ver)
 105    {
 106       i = 0;
 107
 108       do
 109       {
 110          if (user_png_ver[i] != png_libpng_ver[i])
 111             png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 112       } while (png_libpng_ver[i++]);
 113    }
 114
 115    else
 116       png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 117
 118
 119    if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
 120    {
 121      /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
 122       * we must recompile any applications that use any older library version.
 123       * For versions after libpng 1.0, we will be compatible, so we need
 124       * only check the first digit.
 125       */
 126       if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
 127           (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
 128           (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
 129       {
 130 #ifdef PNG_CONSOLE_IO_SUPPORTED
 131          char msg[80];
 132          if (user_png_ver)
 133          {
 134             png_snprintf2(msg, 80,
 135                 "Application built with libpng-%.20s"
 136                 " but running with %.20s",
 137                 user_png_ver,
 138                 png_libpng_ver);
 139             png_warning(png_ptr, msg);
 140          }
 141 #else
 142          png_warning(png_ptr,
 143              "Incompatible libpng version in application and library");
 144 #endif
 145 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 146          png_ptr->flags = 0;
 147 #endif
 148
 149          png_cleanup_needed = 1;
 150       }
 151    }
 152
 153    if (!png_cleanup_needed)
 154    {
 155    /* Initialize zbuf - compression buffer */
 156    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 157    png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr, png_ptr->zbuf_size);
 158
 159    if (png_ptr->zbuf == NULL)
 160       png_cleanup_needed = 1;
 161    }
 162
 163    png_ptr->zstream.zalloc = png_zalloc;
 164    png_ptr->zstream.zfree = png_zfree;
 165    png_ptr->zstream.opaque = (voidpf)png_ptr;
 166
 167    if (!png_cleanup_needed)
 168    {
 169       switch (inflateInit(&png_ptr->zstream))
 170       {
 171          case Z_OK:
 172             break; /* Do nothing */
 173
 174          case Z_MEM_ERROR:
 175             png_warning(png_ptr, "zlib memory error");
 176             png_cleanup_needed = 1;
 177             break;
 178
 179          case Z_STREAM_ERROR:
 180             png_warning(png_ptr, "zlib stream error");
 181             png_cleanup_needed = 1;
 182             break;
 183
 184          case Z_VERSION_ERROR:
 185             png_warning(png_ptr, "zlib version error");
 186             png_cleanup_needed = 1;
 187             break;
 188
 189          default: png_warning(png_ptr, "Unknown zlib error");
 190             png_cleanup_needed = 1;
 191       }
 192    }
 193
 194    if (png_cleanup_needed)
 195    {
 196       /* Clean up PNG structure and deallocate any memory. */
 197       png_free(png_ptr, png_ptr->zbuf);
 198       png_ptr->zbuf = NULL;
 199 #ifdef PNG_USER_MEM_SUPPORTED
 200       png_destroy_struct_2((png_voidp)png_ptr,
 201           (png_free_ptr)free_fn, (png_voidp)mem_ptr);
 202 #else
 203       png_destroy_struct((png_voidp)png_ptr);
 204 #endif
 205       return (NULL);
 206    }
 207
 208    png_ptr->zstream.next_out = png_ptr->zbuf;
 209    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 210
 211    png_set_read_fn(png_ptr, NULL, NULL);
 212
 213
 214    return (png_ptr);
 215 }
 216
 217
 218 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 219 /* Read the information before the actual image data.  This has been
 220  * changed in v0.90 to allow reading a file that already has the magic
 221  * bytes read from the stream.  You can tell libpng how many bytes have
 222  * been read from the beginning of the stream (up to the maximum of 8)
 223  * via png_set_sig_bytes(), and we will only check the remaining bytes
 224  * here.  The application can then have access to the signature bytes we
 225  * read if it is determined that this isn't a valid PNG file.
 226  */
 227 void PNGAPI
 228 png_read_info(png_structp png_ptr, png_infop info_ptr)
 229 {
 230    png_debug(1, "in png_read_info");
 231
 232    if (png_ptr == NULL || info_ptr == NULL)
 233       return;
 234
 235    /* Read and check the PNG file signature. */
 236    png_read_sig(png_ptr, info_ptr);
 237
 238    for (;;)
 239    {
 240       PNG_IHDR;
 241       PNG_IDAT;
 242       PNG_IEND;
 243       PNG_PLTE;
 244 #ifdef PNG_READ_bKGD_SUPPORTED
 245       PNG_bKGD;
 246 #endif
 247 #ifdef PNG_READ_cHRM_SUPPORTED
 248       PNG_cHRM;
 249 #endif
 250 #ifdef PNG_READ_gAMA_SUPPORTED
 251       PNG_gAMA;
 252 #endif
 253 #ifdef PNG_READ_hIST_SUPPORTED
 254       PNG_hIST;
 255 #endif
 256 #ifdef PNG_READ_iCCP_SUPPORTED
 257       PNG_iCCP;
 258 #endif
 259 #ifdef PNG_READ_iTXt_SUPPORTED
 260       PNG_iTXt;
 261 #endif
 262 #ifdef PNG_READ_oFFs_SUPPORTED
 263       PNG_oFFs;
 264 #endif
 265 #ifdef PNG_READ_pCAL_SUPPORTED
 266       PNG_pCAL;
 267 #endif
 268 #ifdef PNG_READ_pHYs_SUPPORTED
 269       PNG_pHYs;
 270 #endif
 271 #ifdef PNG_READ_sBIT_SUPPORTED
 272       PNG_sBIT;
 273 #endif
 274 #ifdef PNG_READ_sCAL_SUPPORTED
 275       PNG_sCAL;
 276 #endif
 277 #ifdef PNG_READ_sPLT_SUPPORTED
 278       PNG_sPLT;
 279 #endif
 280 #ifdef PNG_READ_sRGB_SUPPORTED
 281       PNG_sRGB;
 282 #endif
 283 #ifdef PNG_READ_tEXt_SUPPORTED
 284       PNG_tEXt;
 285 #endif
 286 #ifdef PNG_READ_tIME_SUPPORTED
 287       PNG_tIME;
 288 #endif
 289 #ifdef PNG_READ_tRNS_SUPPORTED
 290       PNG_tRNS;
 291 #endif
 292 #ifdef PNG_READ_zTXt_SUPPORTED
 293       PNG_zTXt;
 294 #endif
 295       png_uint_32 length = png_read_chunk_header(png_ptr);
 296       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
 297
 298       /* This should be a binary subdivision search or a hash for
 299        * matching the chunk name rather than a linear search.
 300        */
 301       if (!png_memcmp(chunk_name, png_IDAT, 4))
 302          if (png_ptr->mode & PNG_AFTER_IDAT)
 303             png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 304
 305       if (!png_memcmp(chunk_name, png_IHDR, 4))
 306          png_handle_IHDR(png_ptr, info_ptr, length);
 307
 308       else if (!png_memcmp(chunk_name, png_IEND, 4))
 309          png_handle_IEND(png_ptr, info_ptr, length);
 310
 311 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 312       else if (png_handle_as_unknown(png_ptr, chunk_name))
 313       {
 314          if (!png_memcmp(chunk_name, png_IDAT, 4))
 315             png_ptr->mode |= PNG_HAVE_IDAT;
 316
 317          png_handle_unknown(png_ptr, info_ptr, length);
 318
 319          if (!png_memcmp(chunk_name, png_PLTE, 4))
 320             png_ptr->mode |= PNG_HAVE_PLTE;
 321
 322          else if (!png_memcmp(chunk_name, png_IDAT, 4))
 323          {
 324             if (!(png_ptr->mode & PNG_HAVE_IHDR))
 325                png_error(png_ptr, "Missing IHDR before IDAT");
 326
 327             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 328                 !(png_ptr->mode & PNG_HAVE_PLTE))
 329                png_error(png_ptr, "Missing PLTE before IDAT");
 330
 331             break;
 332          }
 333       }
 334 #endif
 335       else if (!png_memcmp(chunk_name, png_PLTE, 4))
 336          png_handle_PLTE(png_ptr, info_ptr, length);
 337
 338       else if (!png_memcmp(chunk_name, png_IDAT, 4))
 339       {
 340          if (!(png_ptr->mode & PNG_HAVE_IHDR))
 341             png_error(png_ptr, "Missing IHDR before IDAT");
 342
 343          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 344              !(png_ptr->mode & PNG_HAVE_PLTE))
 345             png_error(png_ptr, "Missing PLTE before IDAT");
 346
 347          png_ptr->idat_size = length;
 348          png_ptr->mode |= PNG_HAVE_IDAT;
 349          break;
 350       }
 351
 352 #ifdef PNG_READ_bKGD_SUPPORTED
 353       else if (!png_memcmp(chunk_name, png_bKGD, 4))
 354          png_handle_bKGD(png_ptr, info_ptr, length);
 355 #endif
 356
 357 #ifdef PNG_READ_cHRM_SUPPORTED
 358       else if (!png_memcmp(chunk_name, png_cHRM, 4))
 359          png_handle_cHRM(png_ptr, info_ptr, length);
 360 #endif
 361
 362 #ifdef PNG_READ_gAMA_SUPPORTED
 363       else if (!png_memcmp(chunk_name, png_gAMA, 4))
 364          png_handle_gAMA(png_ptr, info_ptr, length);
 365 #endif
 366
 367 #ifdef PNG_READ_hIST_SUPPORTED
 368       else if (!png_memcmp(chunk_name, png_hIST, 4))
 369          png_handle_hIST(png_ptr, info_ptr, length);
 370 #endif
 371
 372 #ifdef PNG_READ_oFFs_SUPPORTED
 373       else if (!png_memcmp(chunk_name, png_oFFs, 4))
 374          png_handle_oFFs(png_ptr, info_ptr, length);
 375 #endif
 376
 377 #ifdef PNG_READ_pCAL_SUPPORTED
 378       else if (!png_memcmp(chunk_name, png_pCAL, 4))
 379          png_handle_pCAL(png_ptr, info_ptr, length);
 380 #endif
 381
 382 #ifdef PNG_READ_sCAL_SUPPORTED
 383       else if (!png_memcmp(chunk_name, png_sCAL, 4))
 384          png_handle_sCAL(png_ptr, info_ptr, length);
 385 #endif
 386
 387 #ifdef PNG_READ_pHYs_SUPPORTED
 388       else if (!png_memcmp(chunk_name, png_pHYs, 4))
 389          png_handle_pHYs(png_ptr, info_ptr, length);
 390 #endif
 391
 392 #ifdef PNG_READ_sBIT_SUPPORTED
 393       else if (!png_memcmp(chunk_name, png_sBIT, 4))
 394          png_handle_sBIT(png_ptr, info_ptr, length);
 395 #endif
 396
 397 #ifdef PNG_READ_sRGB_SUPPORTED
 398       else if (!png_memcmp(chunk_name, png_sRGB, 4))
 399          png_handle_sRGB(png_ptr, info_ptr, length);
 400 #endif
 401
 402 #ifdef PNG_READ_iCCP_SUPPORTED
 403       else if (!png_memcmp(chunk_name, png_iCCP, 4))
 404          png_handle_iCCP(png_ptr, info_ptr, length);
 405 #endif
 406
 407 #ifdef PNG_READ_sPLT_SUPPORTED
 408       else if (!png_memcmp(chunk_name, png_sPLT, 4))
 409          png_handle_sPLT(png_ptr, info_ptr, length);
 410 #endif
 411
 412 #ifdef PNG_READ_tEXt_SUPPORTED
 413       else if (!png_memcmp(chunk_name, png_tEXt, 4))
 414          png_handle_tEXt(png_ptr, info_ptr, length);
 415 #endif
 416
 417 #ifdef PNG_READ_tIME_SUPPORTED
 418       else if (!png_memcmp(chunk_name, png_tIME, 4))
 419          png_handle_tIME(png_ptr, info_ptr, length);
 420 #endif
 421
 422 #ifdef PNG_READ_tRNS_SUPPORTED
 423       else if (!png_memcmp(chunk_name, png_tRNS, 4))
 424          png_handle_tRNS(png_ptr, info_ptr, length);
 425 #endif
 426
 427 #ifdef PNG_READ_zTXt_SUPPORTED
 428       else if (!png_memcmp(chunk_name, png_zTXt, 4))
 429          png_handle_zTXt(png_ptr, info_ptr, length);
 430 #endif
 431
 432 #ifdef PNG_READ_iTXt_SUPPORTED
 433       else if (!png_memcmp(chunk_name, png_iTXt, 4))
 434          png_handle_iTXt(png_ptr, info_ptr, length);
 435 #endif
 436
 437       else
 438          png_handle_unknown(png_ptr, info_ptr, length);
 439    }
 440 }
 441 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 442
 443 /* Optional call to update the users info_ptr structure */
 444 void PNGAPI
 445 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 446 {
 447    png_debug(1, "in png_read_update_info");
 448
 449    if (png_ptr == NULL)
 450       return;
 451
 452    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 453       png_read_start_row(png_ptr);
 454
 455    else
 456       png_warning(png_ptr,
 457           "Ignoring extra png_read_update_info() call;"
 458           " row buffer not reallocated");
 459
 460    png_read_transform_info(png_ptr, info_ptr);
 461 }
 462
 463 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 464 /* Initialize palette, background, etc, after transformations
 465  * are set, but before any reading takes place.  This allows
 466  * the user to obtain a gamma-corrected palette, for example.
 467  * If the user doesn't call this, we will do it ourselves.
 468  */
 469 void PNGAPI
 470 png_start_read_image(png_structp png_ptr)
 471 {
 472    png_debug(1, "in png_start_read_image");
 473
 474    if (png_ptr == NULL)
 475       return;
 476
 477    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 478       png_read_start_row(png_ptr);
 479    else
 480       png_warning(png_ptr,
 481           "Ignoring extra png_start_read_image() call;"
 482           " row buffer not reallocated");
 483 }
 484 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 485
 486 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 487 void PNGAPI
 488 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 489 {
 490    PNG_IDAT;
 491    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
 492        0xff};
 493    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 494    int ret;
 495
 496    if (png_ptr == NULL)
 497       return;
 498
 499    png_debug2(1, "in png_read_row (row %lu, pass %d)",
 500        (unsigned long)png_ptr->row_number, png_ptr->pass);
 501
 502    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 503       png_read_start_row(png_ptr);
 504
 505    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
 506    {
 507    /* Check for transforms that have been set but were defined out */
 508 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
 509    if (png_ptr->transformations & PNG_INVERT_MONO)
 510       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
 511 #endif
 512
 513 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
 514    if (png_ptr->transformations & PNG_FILLER)
 515       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
 516 #endif
 517
 518 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
 519     !defined(PNG_READ_PACKSWAP_SUPPORTED)
 520    if (png_ptr->transformations & PNG_PACKSWAP)
 521       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
 522 #endif
 523
 524 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
 525    if (png_ptr->transformations & PNG_PACK)
 526       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
 527 #endif
 528
 529 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
 530    if (png_ptr->transformations & PNG_SHIFT)
 531       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
 532 #endif
 533
 534 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
 535    if (png_ptr->transformations & PNG_BGR)
 536       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
 537 #endif
 538
 539 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
 540    if (png_ptr->transformations & PNG_SWAP_BYTES)
 541       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
 542 #endif
 543    }
 544
 545 #ifdef PNG_READ_INTERLACING_SUPPORTED
 546    /* If interlaced and we do not need a new row, combine row and return */
 547    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 548    {
 549       switch (png_ptr->pass)
 550       {
 551          case 0:
 552             if (png_ptr->row_number & 0x07)
 553             {
 554                if (dsp_row != NULL)
 555                   png_combine_row(png_ptr, dsp_row,
 556                      png_pass_dsp_mask[png_ptr->pass]);
 557                png_read_finish_row(png_ptr);
 558                return;
 559             }
 560             break;
 561
 562          case 1:
 563             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
 564             {
 565                if (dsp_row != NULL)
 566                   png_combine_row(png_ptr, dsp_row,
 567                       png_pass_dsp_mask[png_ptr->pass]);
 568
 569                png_read_finish_row(png_ptr);
 570                return;
 571             }
 572             break;
 573
 574          case 2:
 575             if ((png_ptr->row_number & 0x07) != 4)
 576             {
 577                if (dsp_row != NULL && (png_ptr->row_number & 4))
 578                   png_combine_row(png_ptr, dsp_row,
 579                       png_pass_dsp_mask[png_ptr->pass]);
 580
 581                png_read_finish_row(png_ptr);
 582                return;
 583             }
 584             break;
 585
 586          case 3:
 587             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
 588             {
 589                if (dsp_row != NULL)
 590                   png_combine_row(png_ptr, dsp_row,
 591                       png_pass_dsp_mask[png_ptr->pass]);
 592
 593                png_read_finish_row(png_ptr);
 594                return;
 595             }
 596             break;
 597
 598          case 4:
 599             if ((png_ptr->row_number & 3) != 2)
 600             {
 601                if (dsp_row != NULL && (png_ptr->row_number & 2))
 602                   png_combine_row(png_ptr, dsp_row,
 603                       png_pass_dsp_mask[png_ptr->pass]);
 604
 605                png_read_finish_row(png_ptr);
 606                return;
 607             }
 608             break;
 609          case 5:
 610             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
 611             {
 612                if (dsp_row != NULL)
 613                   png_combine_row(png_ptr, dsp_row,
 614                       png_pass_dsp_mask[png_ptr->pass]);
 615
 616                png_read_finish_row(png_ptr);
 617                return;
 618             }
 619             break;
 620
 621          default:
 622          case 6:
 623             if (!(png_ptr->row_number & 1))
 624             {
 625                png_read_finish_row(png_ptr);
 626                return;
 627             }
 628             break;
 629       }
 630    }
 631 #endif
 632
 633    if (!(png_ptr->mode & PNG_HAVE_IDAT))
 634       png_error(png_ptr, "Invalid attempt to read row data");
 635
 636    png_ptr->zstream.next_out = png_ptr->row_buf;
 637    png_ptr->zstream.avail_out =
 638        (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
 639        png_ptr->iwidth) + 1);
 640
 641    do
 642    {
 643       if (!(png_ptr->zstream.avail_in))
 644       {
 645          while (!png_ptr->idat_size)
 646          {
 647             png_crc_finish(png_ptr, 0);
 648
 649             png_ptr->idat_size = png_read_chunk_header(png_ptr);
 650             if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 651                png_error(png_ptr, "Not enough image data");
 652          }
 653          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
 654          png_ptr->zstream.next_in = png_ptr->zbuf;
 655          if (png_ptr->zbuf_size > png_ptr->idat_size)
 656             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
 657          png_crc_read(png_ptr, png_ptr->zbuf,
 658              (png_size_t)png_ptr->zstream.avail_in);
 659          png_ptr->idat_size -= png_ptr->zstream.avail_in;
 660       }
 661
 662       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 663
 664       if (ret == Z_STREAM_END)
 665       {
 666          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
 667             png_ptr->idat_size)
 668             png_benign_error(png_ptr, "Extra compressed data");
 669          png_ptr->mode |= PNG_AFTER_IDAT;
 670          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 671          break;
 672       }
 673
 674       if (ret != Z_OK)
 675          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
 676              "Decompression error");
 677
 678    } while (png_ptr->zstream.avail_out);
 679
 680    png_ptr->row_info.color_type = png_ptr->color_type;
 681    png_ptr->row_info.width = png_ptr->iwidth;
 682    png_ptr->row_info.channels = png_ptr->channels;
 683    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 684    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 685    png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
 686        png_ptr->row_info.width);
 687
 688    if (png_ptr->row_buf[0])
 689    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 690        png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 691        (int)(png_ptr->row_buf[0]));
 692
 693    png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
 694
 695 #ifdef PNG_MNG_FEATURES_SUPPORTED
 696    if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
 697        (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
 698    {
 699       /* Intrapixel differencing */
 700       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
 701    }
 702 #endif
 703
 704
 705    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
 706       png_do_read_transformations(png_ptr);
 707
 708 #ifdef PNG_READ_INTERLACING_SUPPORTED
 709    /* Blow up interlaced rows to full size */
 710    if (png_ptr->interlaced &&
 711       (png_ptr->transformations & PNG_INTERLACE))
 712    {
 713       if (png_ptr->pass < 6)
 714          /* Old interface (pre-1.0.9):
 715           * png_do_read_interlace(&(png_ptr->row_info),
 716           *    png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 717           */
 718          png_do_read_interlace(png_ptr);
 719
 720       if (dsp_row != NULL)
 721          png_combine_row(png_ptr, dsp_row, png_pass_dsp_mask[png_ptr->pass]);
 722
 723       if (row != NULL)
 724          png_combine_row(png_ptr, row, png_pass_mask[png_ptr->pass]);
 725    }
 726
 727    else
 728 #endif
 729    {
 730       if (row != NULL)
 731          png_combine_row(png_ptr, row, 0xff);
 732
 733       if (dsp_row != NULL)
 734          png_combine_row(png_ptr, dsp_row, 0xff);
 735    }
 736    png_read_finish_row(png_ptr);
 737
 738    if (png_ptr->read_row_fn != NULL)
 739       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
 740 }
 741 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 742
 743 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 744 /* Read one or more rows of image data.  If the image is interlaced,
 745  * and png_set_interlace_handling() has been called, the rows need to
 746  * contain the contents of the rows from the previous pass.  If the
 747  * image has alpha or transparency, and png_handle_alpha()[*] has been
 748  * called, the rows contents must be initialized to the contents of the
 749  * screen.
 750  *
 751  * "row" holds the actual image, and pixels are placed in it
 752  * as they arrive.  If the image is displayed after each pass, it will
 753  * appear to "sparkle" in.  "display_row" can be used to display a
 754  * "chunky" progressive image, with finer detail added as it becomes
 755  * available.  If you do not want this "chunky" display, you may pass
 756  * NULL for display_row.  If you do not want the sparkle display, and
 757  * you have not called png_handle_alpha(), you may pass NULL for rows.
 758  * If you have called png_handle_alpha(), and the image has either an
 759  * alpha channel or a transparency chunk, you must provide a buffer for
 760  * rows.  In this case, you do not have to provide a display_row buffer
 761  * also, but you may.  If the image is not interlaced, or if you have
 762  * not called png_set_interlace_handling(), the display_row buffer will
 763  * be ignored, so pass NULL to it.
 764  *
 765  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 766  */
 767
 768 void PNGAPI
 769 png_read_rows(png_structp png_ptr, png_bytepp row,
 770     png_bytepp display_row, png_uint_32 num_rows)
 771 {
 772    png_uint_32 i;
 773    png_bytepp rp;
 774    png_bytepp dp;
 775
 776    png_debug(1, "in png_read_rows");
 777
 778    if (png_ptr == NULL)
 779       return;
 780
 781    rp = row;
 782    dp = display_row;
 783    if (rp != NULL && dp != NULL)
 784       for (i = 0; i < num_rows; i++)
 785       {
 786          png_bytep rptr = *rp++;
 787          png_bytep dptr = *dp++;
 788
 789          png_read_row(png_ptr, rptr, dptr);
 790       }
 791
 792    else if (rp != NULL)
 793       for (i = 0; i < num_rows; i++)
 794       {
 795          png_bytep rptr = *rp;
 796          png_read_row(png_ptr, rptr, NULL);
 797          rp++;
 798       }
 799
 800    else if (dp != NULL)
 801       for (i = 0; i < num_rows; i++)
 802       {
 803          png_bytep dptr = *dp;
 804          png_read_row(png_ptr, NULL, dptr);
 805          dp++;
 806       }
 807 }
 808 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 809
 810 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 811 /* Read the entire image.  If the image has an alpha channel or a tRNS
 812  * chunk, and you have called png_handle_alpha()[*], you will need to
 813  * initialize the image to the current image that PNG will be overlaying.
 814  * We set the num_rows again here, in case it was incorrectly set in
 815  * png_read_start_row() by a call to png_read_update_info() or
 816  * png_start_read_image() if png_set_interlace_handling() wasn't called
 817  * prior to either of these functions like it should have been.  You can
 818  * only call this function once.  If you desire to have an image for
 819  * each pass of a interlaced image, use png_read_rows() instead.
 820  *
 821  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 822  */
 823 void PNGAPI
 824 png_read_image(png_structp png_ptr, png_bytepp image)
 825 {
 826    png_uint_32 i, image_height;
 827    int pass, j;
 828    png_bytepp rp;
 829
 830    png_debug(1, "in png_read_image");
 831
 832    if (png_ptr == NULL)
 833       return;
 834
 835 #ifdef PNG_READ_INTERLACING_SUPPORTED
 836    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 837    {
 838       pass = png_set_interlace_handling(png_ptr);
 839       /* And make sure transforms are initialized. */
 840       png_start_read_image(png_ptr);
 841    }
 842    else
 843    {
 844       if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
 845       {
 846          /* Caller called png_start_read_image or png_read_update_info without
 847           * first turning on the PNG_INTERLACE transform.  We can fix this here,
 848           * but the caller should do it!
 849           */
 850          png_warning(png_ptr, "Interlace handling should be turned on when "
 851             "using png_read_image");
 852          /* Make sure this is set correctly */
 853          png_ptr->num_rows = png_ptr->height;
 854       }
 855
 856       /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
 857        * the above error case.
 858        */
 859       pass = png_set_interlace_handling(png_ptr);
 860    }
 861 #else
 862    if (png_ptr->interlaced)
 863       png_error(png_ptr,
 864           "Cannot read interlaced image -- interlace handler disabled");
 865
 866    pass = 1;
 867 #endif
 868
 869    image_height=png_ptr->height;
 870
 871    for (j = 0; j < pass; j++)
 872    {
 873       rp = image;
 874       for (i = 0; i < image_height; i++)
 875       {
 876          png_read_row(png_ptr, *rp, NULL);
 877          rp++;
 878       }
 879    }
 880 }
 881 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 882
 883 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 884 /* Read the end of the PNG file.  Will not read past the end of the
 885  * file, will verify the end is accurate, and will read any comments
 886  * or time information at the end of the file, if info is not NULL.
 887  */
 888 void PNGAPI
 889 png_read_end(png_structp png_ptr, png_infop info_ptr)
 890 {
 891    png_debug(1, "in png_read_end");
 892
 893    if (png_ptr == NULL)
 894       return;
 895
 896    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 897
 898    do
 899    {
 900       PNG_IHDR;
 901       PNG_IDAT;
 902       PNG_IEND;
 903       PNG_PLTE;
 904 #ifdef PNG_READ_bKGD_SUPPORTED
 905       PNG_bKGD;
 906 #endif
 907 #ifdef PNG_READ_cHRM_SUPPORTED
 908       PNG_cHRM;
 909 #endif
 910 #ifdef PNG_READ_gAMA_SUPPORTED
 911       PNG_gAMA;
 912 #endif
 913 #ifdef PNG_READ_hIST_SUPPORTED
 914       PNG_hIST;
 915 #endif
 916 #ifdef PNG_READ_iCCP_SUPPORTED
 917       PNG_iCCP;
 918 #endif
 919 #ifdef PNG_READ_iTXt_SUPPORTED
 920       PNG_iTXt;
 921 #endif
 922 #ifdef PNG_READ_oFFs_SUPPORTED
 923       PNG_oFFs;
 924 #endif
 925 #ifdef PNG_READ_pCAL_SUPPORTED
 926       PNG_pCAL;
 927 #endif
 928 #ifdef PNG_READ_pHYs_SUPPORTED
 929       PNG_pHYs;
 930 #endif
 931 #ifdef PNG_READ_sBIT_SUPPORTED
 932       PNG_sBIT;
 933 #endif
 934 #ifdef PNG_READ_sCAL_SUPPORTED
 935       PNG_sCAL;
 936 #endif
 937 #ifdef PNG_READ_sPLT_SUPPORTED
 938       PNG_sPLT;
 939 #endif
 940 #ifdef PNG_READ_sRGB_SUPPORTED
 941       PNG_sRGB;
 942 #endif
 943 #ifdef PNG_READ_tEXt_SUPPORTED
 944       PNG_tEXt;
 945 #endif
 946 #ifdef PNG_READ_tIME_SUPPORTED
 947       PNG_tIME;
 948 #endif
 949 #ifdef PNG_READ_tRNS_SUPPORTED
 950       PNG_tRNS;
 951 #endif
 952 #ifdef PNG_READ_zTXt_SUPPORTED
 953       PNG_zTXt;
 954 #endif
 955       png_uint_32 length = png_read_chunk_header(png_ptr);
 956       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
 957
 958       if (!png_memcmp(chunk_name, png_IHDR, 4))
 959          png_handle_IHDR(png_ptr, info_ptr, length);
 960
 961       else if (!png_memcmp(chunk_name, png_IEND, 4))
 962          png_handle_IEND(png_ptr, info_ptr, length);
 963
 964 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 965       else if (png_handle_as_unknown(png_ptr, chunk_name))
 966       {
 967          if (!png_memcmp(chunk_name, png_IDAT, 4))
 968          {
 969             if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 970                png_benign_error(png_ptr, "Too many IDATs found");
 971          }
 972          png_handle_unknown(png_ptr, info_ptr, length);
 973          if (!png_memcmp(chunk_name, png_PLTE, 4))
 974             png_ptr->mode |= PNG_HAVE_PLTE;
 975       }
 976 #endif
 977
 978       else if (!png_memcmp(chunk_name, png_IDAT, 4))
 979       {
 980          /* Zero length IDATs are legal after the last IDAT has been
 981           * read, but not after other chunks have been read.
 982           */
 983          if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 984             png_benign_error(png_ptr, "Too many IDATs found");
 985
 986          png_crc_finish(png_ptr, length);
 987       }
 988       else if (!png_memcmp(chunk_name, png_PLTE, 4))
 989          png_handle_PLTE(png_ptr, info_ptr, length);
 990
 991 #ifdef PNG_READ_bKGD_SUPPORTED
 992       else if (!png_memcmp(chunk_name, png_bKGD, 4))
 993          png_handle_bKGD(png_ptr, info_ptr, length);
 994 #endif
 995
 996 #ifdef PNG_READ_cHRM_SUPPORTED
 997       else if (!png_memcmp(chunk_name, png_cHRM, 4))
 998          png_handle_cHRM(png_ptr, info_ptr, length);
 999 #endif
1000
1001 #ifdef PNG_READ_gAMA_SUPPORTED
1002       else if (!png_memcmp(chunk_name, png_gAMA, 4))
1003          png_handle_gAMA(png_ptr, info_ptr, length);
1004 #endif
1005
1006 #ifdef PNG_READ_hIST_SUPPORTED
1007       else if (!png_memcmp(chunk_name, png_hIST, 4))
1008          png_handle_hIST(png_ptr, info_ptr, length);
1009 #endif
1010
1011 #ifdef PNG_READ_oFFs_SUPPORTED
1012       else if (!png_memcmp(chunk_name, png_oFFs, 4))
1013          png_handle_oFFs(png_ptr, info_ptr, length);
1014 #endif
1015
1016 #ifdef PNG_READ_pCAL_SUPPORTED
1017       else if (!png_memcmp(chunk_name, png_pCAL, 4))
1018          png_handle_pCAL(png_ptr, info_ptr, length);
1019 #endif
1020
1021 #ifdef PNG_READ_sCAL_SUPPORTED
1022       else if (!png_memcmp(chunk_name, png_sCAL, 4))
1023          png_handle_sCAL(png_ptr, info_ptr, length);
1024 #endif
1025
1026 #ifdef PNG_READ_pHYs_SUPPORTED
1027       else if (!png_memcmp(chunk_name, png_pHYs, 4))
1028          png_handle_pHYs(png_ptr, info_ptr, length);
1029 #endif
1030
1031 #ifdef PNG_READ_sBIT_SUPPORTED
1032       else if (!png_memcmp(chunk_name, png_sBIT, 4))
1033          png_handle_sBIT(png_ptr, info_ptr, length);
1034 #endif
1035
1036 #ifdef PNG_READ_sRGB_SUPPORTED
1037       else if (!png_memcmp(chunk_name, png_sRGB, 4))
1038          png_handle_sRGB(png_ptr, info_ptr, length);
1039 #endif
1040
1041 #ifdef PNG_READ_iCCP_SUPPORTED
1042       else if (!png_memcmp(chunk_name, png_iCCP, 4))
1043          png_handle_iCCP(png_ptr, info_ptr, length);
1044 #endif
1045
1046 #ifdef PNG_READ_sPLT_SUPPORTED
1047       else if (!png_memcmp(chunk_name, png_sPLT, 4))
1048          png_handle_sPLT(png_ptr, info_ptr, length);
1049 #endif
1050
1051 #ifdef PNG_READ_tEXt_SUPPORTED
1052       else if (!png_memcmp(chunk_name, png_tEXt, 4))
1053          png_handle_tEXt(png_ptr, info_ptr, length);
1054 #endif
1055
1056 #ifdef PNG_READ_tIME_SUPPORTED
1057       else if (!png_memcmp(chunk_name, png_tIME, 4))
1058          png_handle_tIME(png_ptr, info_ptr, length);
1059 #endif
1060
1061 #ifdef PNG_READ_tRNS_SUPPORTED
1062       else if (!png_memcmp(chunk_name, png_tRNS, 4))
1063          png_handle_tRNS(png_ptr, info_ptr, length);
1064 #endif
1065
1066 #ifdef PNG_READ_zTXt_SUPPORTED
1067       else if (!png_memcmp(chunk_name, png_zTXt, 4))
1068          png_handle_zTXt(png_ptr, info_ptr, length);
1069 #endif
1070
1071 #ifdef PNG_READ_iTXt_SUPPORTED
1072       else if (!png_memcmp(chunk_name, png_iTXt, 4))
1073          png_handle_iTXt(png_ptr, info_ptr, length);
1074 #endif
1075
1076       else
1077          png_handle_unknown(png_ptr, info_ptr, length);
1078    } while (!(png_ptr->mode & PNG_HAVE_IEND));
1079 }
1080 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1081
1082 /* Free all memory used by the read */
1083 void PNGAPI
1084 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1085     png_infopp end_info_ptr_ptr)
1086 {
1087    png_structp png_ptr = NULL;
1088    png_infop info_ptr = NULL, end_info_ptr = NULL;
1089 #ifdef PNG_USER_MEM_SUPPORTED
1090    png_free_ptr free_fn = NULL;
1091    png_voidp mem_ptr = NULL;
1092 #endif
1093
1094    png_debug(1, "in png_destroy_read_struct");
1095
1096    if (png_ptr_ptr != NULL)
1097       png_ptr = *png_ptr_ptr;
1098    if (png_ptr == NULL)
1099       return;
1100
1101 #ifdef PNG_USER_MEM_SUPPORTED
1102    free_fn = png_ptr->free_fn;
1103    mem_ptr = png_ptr->mem_ptr;
1104 #endif
1105
1106    if (info_ptr_ptr != NULL)
1107       info_ptr = *info_ptr_ptr;
1108
1109    if (end_info_ptr_ptr != NULL)
1110       end_info_ptr = *end_info_ptr_ptr;
1111
1112    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1113
1114    if (info_ptr != NULL)
1115    {
1116 #ifdef PNG_TEXT_SUPPORTED
1117       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1118 #endif
1119
1120 #ifdef PNG_USER_MEM_SUPPORTED
1121       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1122           (png_voidp)mem_ptr);
1123 #else
1124       png_destroy_struct((png_voidp)info_ptr);
1125 #endif
1126       *info_ptr_ptr = NULL;
1127    }
1128
1129    if (end_info_ptr != NULL)
1130    {
1131 #ifdef PNG_READ_TEXT_SUPPORTED
1132       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1133 #endif
1134 #ifdef PNG_USER_MEM_SUPPORTED
1135       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1136           (png_voidp)mem_ptr);
1137 #else
1138       png_destroy_struct((png_voidp)end_info_ptr);
1139 #endif
1140       *end_info_ptr_ptr = NULL;
1141    }
1142
1143    if (png_ptr != NULL)
1144    {
1145 #ifdef PNG_USER_MEM_SUPPORTED
1146       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1147           (png_voidp)mem_ptr);
1148 #else
1149       png_destroy_struct((png_voidp)png_ptr);
1150 #endif
1151       *png_ptr_ptr = NULL;
1152    }
1153 }
1154
1155 /* Free all memory used by the read (old method) */
1156 void /* PRIVATE */
1157 png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1158     png_infop end_info_ptr)
1159 {
1160 #ifdef PNG_SETJMP_SUPPORTED
1161    jmp_buf tmp_jmp;
1162 #endif
1163    png_error_ptr error_fn;
1164    png_error_ptr warning_fn;
1165    png_voidp error_ptr;
1166 #ifdef PNG_USER_MEM_SUPPORTED
1167    png_free_ptr free_fn;
1168 #endif
1169
1170    png_debug(1, "in png_read_destroy");
1171
1172    if (info_ptr != NULL)
1173       png_info_destroy(png_ptr, info_ptr);
1174
1175    if (end_info_ptr != NULL)
1176       png_info_destroy(png_ptr, end_info_ptr);
1177
1178    png_free(png_ptr, png_ptr->zbuf);
1179    png_free(png_ptr, png_ptr->big_row_buf);
1180    png_free(png_ptr, png_ptr->prev_row);
1181    png_free(png_ptr, png_ptr->chunkdata);
1182
1183 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1184    png_free(png_ptr, png_ptr->palette_lookup);
1185    png_free(png_ptr, png_ptr->quantize_index);
1186 #endif
1187
1188 #ifdef PNG_READ_GAMMA_SUPPORTED
1189    png_free(png_ptr, png_ptr->gamma_table);
1190 #endif
1191
1192 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1193    png_free(png_ptr, png_ptr->gamma_from_1);
1194    png_free(png_ptr, png_ptr->gamma_to_1);
1195 #endif
1196
1197    if (png_ptr->free_me & PNG_FREE_PLTE)
1198       png_zfree(png_ptr, png_ptr->palette);
1199    png_ptr->free_me &= ~PNG_FREE_PLTE;
1200
1201 #if defined(PNG_tRNS_SUPPORTED) || \
1202     defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1203    if (png_ptr->free_me & PNG_FREE_TRNS)
1204       png_free(png_ptr, png_ptr->trans_alpha);
1205    png_ptr->free_me &= ~PNG_FREE_TRNS;
1206 #endif
1207
1208 #ifdef PNG_READ_hIST_SUPPORTED
1209    if (png_ptr->free_me & PNG_FREE_HIST)
1210       png_free(png_ptr, png_ptr->hist);
1211    png_ptr->free_me &= ~PNG_FREE_HIST;
1212 #endif
1213
1214 #ifdef PNG_READ_GAMMA_SUPPORTED
1215    if (png_ptr->gamma_16_table != NULL)
1216    {
1217       int i;
1218       int istop = (1 << (8 - png_ptr->gamma_shift));
1219       for (i = 0; i < istop; i++)
1220       {
1221          png_free(png_ptr, png_ptr->gamma_16_table[i]);
1222       }
1223    png_free(png_ptr, png_ptr->gamma_16_table);
1224    }
1225
1226 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1227    if (png_ptr->gamma_16_from_1 != NULL)
1228    {
1229       int i;
1230       int istop = (1 << (8 - png_ptr->gamma_shift));
1231       for (i = 0; i < istop; i++)
1232       {
1233          png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1234       }
1235    png_free(png_ptr, png_ptr->gamma_16_from_1);
1236    }
1237    if (png_ptr->gamma_16_to_1 != NULL)
1238    {
1239       int i;
1240       int istop = (1 << (8 - png_ptr->gamma_shift));
1241       for (i = 0; i < istop; i++)
1242       {
1243          png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1244       }
1245    png_free(png_ptr, png_ptr->gamma_16_to_1);
1246    }
1247 #endif
1248 #endif
1249
1250 #ifdef PNG_TIME_RFC1123_SUPPORTED
1251    png_free(png_ptr, png_ptr->time_buffer);
1252 #endif
1253
1254    inflateEnd(&png_ptr->zstream);
1255
1256 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1257    png_free(png_ptr, png_ptr->save_buffer);
1258 #endif
1259
1260 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1261 #ifdef PNG_TEXT_SUPPORTED
1262    png_free(png_ptr, png_ptr->current_text);
1263 #endif /* PNG_TEXT_SUPPORTED */
1264 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1265
1266    /* Save the important info out of the png_struct, in case it is
1267     * being used again.
1268     */
1269 #ifdef PNG_SETJMP_SUPPORTED
1270    png_memcpy(tmp_jmp, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
1271 #endif
1272
1273    error_fn = png_ptr->error_fn;
1274    warning_fn = png_ptr->warning_fn;
1275    error_ptr = png_ptr->error_ptr;
1276 #ifdef PNG_USER_MEM_SUPPORTED
1277    free_fn = png_ptr->free_fn;
1278 #endif
1279
1280    png_memset(png_ptr, 0, png_sizeof(png_struct));
1281
1282    png_ptr->error_fn = error_fn;
1283    png_ptr->warning_fn = warning_fn;
1284    png_ptr->error_ptr = error_ptr;
1285 #ifdef PNG_USER_MEM_SUPPORTED
1286    png_ptr->free_fn = free_fn;
1287 #endif
1288
1289 #ifdef PNG_SETJMP_SUPPORTED
1290    png_memcpy(png_ptr->png_jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
1291 #endif
1292
1293 }
1294
1295 void PNGAPI
1296 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1297 {
1298    if (png_ptr == NULL)
1299       return;
1300
1301    png_ptr->read_row_fn = read_row_fn;
1302 }
1303
1304
1305 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1306 #ifdef PNG_INFO_IMAGE_SUPPORTED
1307 void PNGAPI
1308 png_read_png(png_structp png_ptr, png_infop info_ptr,
1309                            int transforms,
1310                            voidp params)
1311 {
1312    int row;
1313
1314    if (png_ptr == NULL)
1315       return;
1316
1317    /* png_read_info() gives us all of the information from the
1318     * PNG file before the first IDAT (image data chunk).
1319     */
1320    png_read_info(png_ptr, info_ptr);
1321    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1322       png_error(png_ptr, "Image is too high to process with png_read_png()");
1323
1324    /* -------------- image transformations start here ------------------- */
1325
1326 #ifdef PNG_READ_16_TO_8_SUPPORTED
1327    /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
1328     */
1329    if (transforms & PNG_TRANSFORM_STRIP_16)
1330       png_set_strip_16(png_ptr);
1331 #endif
1332
1333 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1334    /* Strip alpha bytes from the input data without combining with
1335     * the background (not recommended).
1336     */
1337    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1338       png_set_strip_alpha(png_ptr);
1339 #endif
1340
1341 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1342    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1343     * byte into separate bytes (useful for paletted and grayscale images).
1344     */
1345    if (transforms & PNG_TRANSFORM_PACKING)
1346       png_set_packing(png_ptr);
1347 #endif
1348
1349 #ifdef PNG_READ_PACKSWAP_SUPPORTED
1350    /* Change the order of packed pixels to least significant bit first
1351     * (not useful if you are using png_set_packing).
1352     */
1353    if (transforms & PNG_TRANSFORM_PACKSWAP)
1354       png_set_packswap(png_ptr);
1355 #endif
1356
1357 #ifdef PNG_READ_EXPAND_SUPPORTED
1358    /* Expand paletted colors into true RGB triplets
1359     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1360     * Expand paletted or RGB images with transparency to full alpha
1361     * channels so the data will be available as RGBA quartets.
1362     */
1363    if (transforms & PNG_TRANSFORM_EXPAND)
1364       if ((png_ptr->bit_depth < 8) ||
1365           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1366           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1367          png_set_expand(png_ptr);
1368 #endif
1369
1370    /* We don't handle background color or gamma transformation or quantizing.
1371     */
1372
1373 #ifdef PNG_READ_INVERT_SUPPORTED
1374    /* Invert monochrome files to have 0 as white and 1 as black
1375     */
1376    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1377       png_set_invert_mono(png_ptr);
1378 #endif
1379
1380 #ifdef PNG_READ_SHIFT_SUPPORTED
1381    /* If you want to shift the pixel values from the range [0,255] or
1382     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1383     * colors were originally in:
1384     */
1385    if ((transforms & PNG_TRANSFORM_SHIFT)
1386        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1387    {
1388       png_color_8p sig_bit;
1389
1390       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1391       png_set_shift(png_ptr, sig_bit);
1392    }
1393 #endif
1394
1395 #ifdef PNG_READ_BGR_SUPPORTED
1396    /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
1397    if (transforms & PNG_TRANSFORM_BGR)
1398       png_set_bgr(png_ptr);
1399 #endif
1400
1401 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1402    /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
1403    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1404       png_set_swap_alpha(png_ptr);
1405 #endif
1406
1407 #ifdef PNG_READ_SWAP_SUPPORTED
1408    /* Swap bytes of 16 bit files to least significant byte first */
1409    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1410       png_set_swap(png_ptr);
1411 #endif
1412
1413 /* Added at libpng-1.2.41 */
1414 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1415    /* Invert the alpha channel from opacity to transparency */
1416    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1417       png_set_invert_alpha(png_ptr);
1418 #endif
1419
1420 /* Added at libpng-1.2.41 */
1421 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1422    /* Expand grayscale image to RGB */
1423    if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1424       png_set_gray_to_rgb(png_ptr);
1425 #endif
1426
1427    /* We don't handle adding filler bytes */
1428
1429    /* Optional call to gamma correct and add the background to the palette
1430     * and update info structure.  REQUIRED if you are expecting libpng to
1431     * update the palette for you (i.e., you selected such a transform above).
1432     */
1433    png_read_update_info(png_ptr, info_ptr);
1434
1435    /* -------------- image transformations end here ------------------- */
1436
1437    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1438    if (info_ptr->row_pointers == NULL)
1439    {
1440       png_uint_32 iptr;
1441
1442       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1443           info_ptr->height * png_sizeof(png_bytep));
1444       for (iptr=0; iptr<info_ptr->height; iptr++)
1445          info_ptr->row_pointers[iptr] = NULL;
1446
1447       info_ptr->free_me |= PNG_FREE_ROWS;
1448
1449       for (row = 0; row < (int)info_ptr->height; row++)
1450          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1451             png_get_rowbytes(png_ptr, info_ptr));
1452    }
1453
1454    png_read_image(png_ptr, info_ptr->row_pointers);
1455    info_ptr->valid |= PNG_INFO_IDAT;
1456
1457    /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1458    png_read_end(png_ptr, info_ptr);
1459
1460    PNG_UNUSED(transforms)   /* Quiet compiler warnings */
1461    PNG_UNUSED(params)
1462
1463 }
1464 #endif /* PNG_INFO_IMAGE_SUPPORTED */
1465 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1466 #endif /* PNG_READ_SUPPORTED */