src/png/pngread.c

   1
   2 /* pngread.c - read a PNG file
   3  *
   4  * Last changed in libpng 1.4.1 [February 25, 2010]
   5  * Copyright (c) 1998-2010 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 #define PNG_NO_PEDANTIC_WARNINGS
  18 #include "png.h"
  19 #ifdef PNG_READ_SUPPORTED
  20 #include "pngpriv.h"
  21
  22
  23 /* Create a PNG structure for reading, and allocate any memory needed. */
  24 png_structp PNGAPI
  25 png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
  26    png_error_ptr error_fn, png_error_ptr warn_fn)
  27 {
  28
  29 #ifdef PNG_USER_MEM_SUPPORTED
  30    return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
  31       warn_fn, NULL, NULL, NULL));
  32 }
  33
  34 /* Alternate create PNG structure for reading, and allocate any memory
  35  * needed.
  36  */
  37 png_structp PNGAPI
  38 png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
  39    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
  40    png_malloc_ptr malloc_fn, png_free_ptr free_fn)
  41 {
  42 #endif /* PNG_USER_MEM_SUPPORTED */
  43
  44 #ifdef PNG_SETJMP_SUPPORTED
  45    volatile
  46 #endif
  47    png_structp png_ptr;
  48    volatile int png_cleanup_needed = 0;
  49
  50 #ifdef PNG_SETJMP_SUPPORTED
  51 #ifdef USE_FAR_KEYWORD
  52    jmp_buf jmpbuf;
  53 #endif
  54 #endif
  55
  56    int i;
  57
  58    png_debug(1, "in png_create_read_struct");
  59
  60 #ifdef PNG_USER_MEM_SUPPORTED
  61    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
  62       malloc_fn, mem_ptr);
  63 #else
  64    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
  65 #endif
  66    if (png_ptr == NULL)
  67       return (NULL);
  68
  69    /* Added at libpng-1.2.6 */
  70 #ifdef PNG_USER_LIMITS_SUPPORTED
  71    png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
  72    png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
  73 #  ifdef PNG_USER_CHUNK_CACHE_MAX
  74    /* Added at libpng-1.2.43 and 1.4.0 */
  75    png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
  76 #  endif
  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(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), 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       do
 108       {
 109          if (user_png_ver[i] != png_libpng_ver[i])
 110             png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 111       } while (png_libpng_ver[i++]);
 112     }
 113     else
 114          png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 115
 116
 117     if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
 118     {
 119        /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
 120        * we must recompile any applications that use any older library version.
 121        * For versions after libpng 1.0, we will be compatible, so we need
 122        * only check the first digit.
 123        */
 124       if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
 125           (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
 126           (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
 127       {
 128 #ifdef PNG_STDIO_SUPPORTED
 129          char msg[80];
 130          if (user_png_ver)
 131          {
 132            png_snprintf(msg, 80,
 133               "Application was compiled with png.h from libpng-%.20s",
 134               user_png_ver);
 135            png_warning(png_ptr, msg);
 136          }
 137          png_snprintf(msg, 80,
 138              "Application  is  running with png.c from libpng-%.20s",
 139              png_libpng_ver);
 140          png_warning(png_ptr, msg);
 141 #endif
 142 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 143          png_ptr->flags = 0;
 144 #endif
 145          png_warning(png_ptr,
 146             "Incompatible libpng version in application and library");
 147
 148          png_cleanup_needed = 1;
 149       }
 150    }
 151
 152    if (!png_cleanup_needed)
 153    {
 154    /* Initialize zbuf - compression buffer */
 155    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 156    png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr,
 157      png_ptr->zbuf_size);
 158    if (png_ptr->zbuf == NULL)
 159         png_cleanup_needed = 1;
 160    }
 161    png_ptr->zstream.zalloc = png_zalloc;
 162    png_ptr->zstream.zfree = png_zfree;
 163    png_ptr->zstream.opaque = (voidpf)png_ptr;
 164
 165    if (!png_cleanup_needed)
 166    {
 167       switch (inflateInit(&png_ptr->zstream))
 168       {
 169          case Z_OK: /* Do nothing */ break;
 170          case Z_MEM_ERROR:
 171          case Z_STREAM_ERROR: png_warning(png_ptr, "zlib memory error");
 172             png_cleanup_needed = 1; break;
 173          case Z_VERSION_ERROR: png_warning(png_ptr, "zlib version error");
 174             png_cleanup_needed = 1; break;
 175          default: png_warning(png_ptr, "Unknown zlib error");
 176             png_cleanup_needed = 1;
 177       }
 178    }
 179
 180    if (png_cleanup_needed)
 181    {
 182       /* Clean up PNG structure and deallocate any memory. */
 183       png_free(png_ptr, png_ptr->zbuf);
 184       png_ptr->zbuf = NULL;
 185 #ifdef PNG_USER_MEM_SUPPORTED
 186       png_destroy_struct_2((png_voidp)png_ptr,
 187          (png_free_ptr)free_fn, (png_voidp)mem_ptr);
 188 #else
 189       png_destroy_struct((png_voidp)png_ptr);
 190 #endif
 191       return (NULL);
 192    }
 193
 194    png_ptr->zstream.next_out = png_ptr->zbuf;
 195    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 196
 197    png_set_read_fn(png_ptr, NULL, NULL);
 198
 199
 200    return (png_ptr);
 201 }
 202
 203
 204 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 205 /* Read the information before the actual image data.  This has been
 206  * changed in v0.90 to allow reading a file that already has the magic
 207  * bytes read from the stream.  You can tell libpng how many bytes have
 208  * been read from the beginning of the stream (up to the maximum of 8)
 209  * via png_set_sig_bytes(), and we will only check the remaining bytes
 210  * here.  The application can then have access to the signature bytes we
 211  * read if it is determined that this isn't a valid PNG file.
 212  */
 213 void PNGAPI
 214 png_read_info(png_structp png_ptr, png_infop info_ptr)
 215 {
 216    png_debug(1, "in png_read_info");
 217
 218    if (png_ptr == NULL || info_ptr == NULL)
 219       return;
 220
 221    /* If we haven't checked all of the PNG signature bytes, do so now. */
 222    if (png_ptr->sig_bytes < 8)
 223    {
 224       png_size_t num_checked = png_ptr->sig_bytes,
 225                  num_to_check = 8 - num_checked;
 226
 227 #ifdef PNG_IO_STATE_SUPPORTED
 228       png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
 229 #endif
 230
 231       png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
 232       png_ptr->sig_bytes = 8;
 233
 234       if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
 235       {
 236          if (num_checked < 4 &&
 237              png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
 238             png_error(png_ptr, "Not a PNG file");
 239          else
 240             png_error(png_ptr, "PNG file corrupted by ASCII conversion");
 241       }
 242       if (num_checked < 3)
 243          png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
 244    }
 245
 246    for (;;)
 247    {
 248       PNG_IHDR;
 249       PNG_IDAT;
 250       PNG_IEND;
 251       PNG_PLTE;
 252 #ifdef PNG_READ_bKGD_SUPPORTED
 253       PNG_bKGD;
 254 #endif
 255 #ifdef PNG_READ_cHRM_SUPPORTED
 256       PNG_cHRM;
 257 #endif
 258 #ifdef PNG_READ_gAMA_SUPPORTED
 259       PNG_gAMA;
 260 #endif
 261 #ifdef PNG_READ_hIST_SUPPORTED
 262       PNG_hIST;
 263 #endif
 264 #ifdef PNG_READ_iCCP_SUPPORTED
 265       PNG_iCCP;
 266 #endif
 267 #ifdef PNG_READ_iTXt_SUPPORTED
 268       PNG_iTXt;
 269 #endif
 270 #ifdef PNG_READ_oFFs_SUPPORTED
 271       PNG_oFFs;
 272 #endif
 273 #ifdef PNG_READ_pCAL_SUPPORTED
 274       PNG_pCAL;
 275 #endif
 276 #ifdef PNG_READ_pHYs_SUPPORTED
 277       PNG_pHYs;
 278 #endif
 279 #ifdef PNG_READ_sBIT_SUPPORTED
 280       PNG_sBIT;
 281 #endif
 282 #ifdef PNG_READ_sCAL_SUPPORTED
 283       PNG_sCAL;
 284 #endif
 285 #ifdef PNG_READ_sPLT_SUPPORTED
 286       PNG_sPLT;
 287 #endif
 288 #ifdef PNG_READ_sRGB_SUPPORTED
 289       PNG_sRGB;
 290 #endif
 291 #ifdef PNG_READ_tEXt_SUPPORTED
 292       PNG_tEXt;
 293 #endif
 294 #ifdef PNG_READ_tIME_SUPPORTED
 295       PNG_tIME;
 296 #endif
 297 #ifdef PNG_READ_tRNS_SUPPORTED
 298       PNG_tRNS;
 299 #endif
 300 #ifdef PNG_READ_zTXt_SUPPORTED
 301       PNG_zTXt;
 302 #endif
 303       png_uint_32 length = png_read_chunk_header(png_ptr);
 304       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
 305
 306       /* This should be a binary subdivision search or a hash for
 307        * matching the chunk name rather than a linear search.
 308        */
 309       if (!png_memcmp(chunk_name, png_IDAT, 4))
 310         if (png_ptr->mode & PNG_AFTER_IDAT)
 311           png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 312
 313       if (!png_memcmp(chunk_name, png_IHDR, 4))
 314          png_handle_IHDR(png_ptr, info_ptr, length);
 315       else if (!png_memcmp(chunk_name, png_IEND, 4))
 316          png_handle_IEND(png_ptr, info_ptr, length);
 317 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 318       else if (png_handle_as_unknown(png_ptr, chunk_name))
 319       {
 320          if (!png_memcmp(chunk_name, png_IDAT, 4))
 321             png_ptr->mode |= PNG_HAVE_IDAT;
 322          png_handle_unknown(png_ptr, info_ptr, length);
 323          if (!png_memcmp(chunk_name, png_PLTE, 4))
 324             png_ptr->mode |= PNG_HAVE_PLTE;
 325          else if (!png_memcmp(chunk_name, png_IDAT, 4))
 326          {
 327             if (!(png_ptr->mode & PNG_HAVE_IHDR))
 328                png_error(png_ptr, "Missing IHDR before IDAT");
 329             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 330                      !(png_ptr->mode & PNG_HAVE_PLTE))
 331                png_error(png_ptr, "Missing PLTE before IDAT");
 332             break;
 333          }
 334       }
 335 #endif
 336       else if (!png_memcmp(chunk_name, png_PLTE, 4))
 337          png_handle_PLTE(png_ptr, info_ptr, length);
 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          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 343                   !(png_ptr->mode & PNG_HAVE_PLTE))
 344             png_error(png_ptr, "Missing PLTE before IDAT");
 345
 346          png_ptr->idat_size = length;
 347          png_ptr->mode |= PNG_HAVE_IDAT;
 348          break;
 349       }
 350 #ifdef PNG_READ_bKGD_SUPPORTED
 351       else if (!png_memcmp(chunk_name, png_bKGD, 4))
 352          png_handle_bKGD(png_ptr, info_ptr, length);
 353 #endif
 354 #ifdef PNG_READ_cHRM_SUPPORTED
 355       else if (!png_memcmp(chunk_name, png_cHRM, 4))
 356          png_handle_cHRM(png_ptr, info_ptr, length);
 357 #endif
 358 #ifdef PNG_READ_gAMA_SUPPORTED
 359       else if (!png_memcmp(chunk_name, png_gAMA, 4))
 360          png_handle_gAMA(png_ptr, info_ptr, length);
 361 #endif
 362 #ifdef PNG_READ_hIST_SUPPORTED
 363       else if (!png_memcmp(chunk_name, png_hIST, 4))
 364          png_handle_hIST(png_ptr, info_ptr, length);
 365 #endif
 366 #ifdef PNG_READ_oFFs_SUPPORTED
 367       else if (!png_memcmp(chunk_name, png_oFFs, 4))
 368          png_handle_oFFs(png_ptr, info_ptr, length);
 369 #endif
 370 #ifdef PNG_READ_pCAL_SUPPORTED
 371       else if (!png_memcmp(chunk_name, png_pCAL, 4))
 372          png_handle_pCAL(png_ptr, info_ptr, length);
 373 #endif
 374 #ifdef PNG_READ_sCAL_SUPPORTED
 375       else if (!png_memcmp(chunk_name, png_sCAL, 4))
 376          png_handle_sCAL(png_ptr, info_ptr, length);
 377 #endif
 378 #ifdef PNG_READ_pHYs_SUPPORTED
 379       else if (!png_memcmp(chunk_name, png_pHYs, 4))
 380          png_handle_pHYs(png_ptr, info_ptr, length);
 381 #endif
 382 #ifdef PNG_READ_sBIT_SUPPORTED
 383       else if (!png_memcmp(chunk_name, png_sBIT, 4))
 384          png_handle_sBIT(png_ptr, info_ptr, length);
 385 #endif
 386 #ifdef PNG_READ_sRGB_SUPPORTED
 387       else if (!png_memcmp(chunk_name, png_sRGB, 4))
 388          png_handle_sRGB(png_ptr, info_ptr, length);
 389 #endif
 390 #ifdef PNG_READ_iCCP_SUPPORTED
 391       else if (!png_memcmp(chunk_name, png_iCCP, 4))
 392          png_handle_iCCP(png_ptr, info_ptr, length);
 393 #endif
 394 #ifdef PNG_READ_sPLT_SUPPORTED
 395       else if (!png_memcmp(chunk_name, png_sPLT, 4))
 396          png_handle_sPLT(png_ptr, info_ptr, length);
 397 #endif
 398 #ifdef PNG_READ_tEXt_SUPPORTED
 399       else if (!png_memcmp(chunk_name, png_tEXt, 4))
 400          png_handle_tEXt(png_ptr, info_ptr, length);
 401 #endif
 402 #ifdef PNG_READ_tIME_SUPPORTED
 403       else if (!png_memcmp(chunk_name, png_tIME, 4))
 404          png_handle_tIME(png_ptr, info_ptr, length);
 405 #endif
 406 #ifdef PNG_READ_tRNS_SUPPORTED
 407       else if (!png_memcmp(chunk_name, png_tRNS, 4))
 408          png_handle_tRNS(png_ptr, info_ptr, length);
 409 #endif
 410 #ifdef PNG_READ_zTXt_SUPPORTED
 411       else if (!png_memcmp(chunk_name, png_zTXt, 4))
 412          png_handle_zTXt(png_ptr, info_ptr, length);
 413 #endif
 414 #ifdef PNG_READ_iTXt_SUPPORTED
 415       else if (!png_memcmp(chunk_name, png_iTXt, 4))
 416          png_handle_iTXt(png_ptr, info_ptr, length);
 417 #endif
 418       else
 419          png_handle_unknown(png_ptr, info_ptr, length);
 420    }
 421 }
 422 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 423
 424 /* Optional call to update the users info_ptr structure */
 425 void PNGAPI
 426 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 427 {
 428    png_debug(1, "in png_read_update_info");
 429
 430    if (png_ptr == NULL)
 431       return;
 432    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 433       png_read_start_row(png_ptr);
 434    else
 435       png_warning(png_ptr,
 436       "Ignoring extra png_read_update_info() call; row buffer not reallocated");
 437
 438    png_read_transform_info(png_ptr, info_ptr);
 439 }
 440
 441 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 442 /* Initialize palette, background, etc, after transformations
 443  * are set, but before any reading takes place.  This allows
 444  * the user to obtain a gamma-corrected palette, for example.
 445  * If the user doesn't call this, we will do it ourselves.
 446  */
 447 void PNGAPI
 448 png_start_read_image(png_structp png_ptr)
 449 {
 450    png_debug(1, "in png_start_read_image");
 451
 452    if (png_ptr == NULL)
 453       return;
 454    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 455       png_read_start_row(png_ptr);
 456 }
 457 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 458
 459 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 460 void PNGAPI
 461 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 462 {
 463    PNG_IDAT;
 464    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
 465       0xff};
 466    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 467    int ret;
 468
 469    if (png_ptr == NULL)
 470       return;
 471
 472    png_debug2(1, "in png_read_row (row %lu, pass %d)",
 473       (unsigned long) png_ptr->row_number, png_ptr->pass);
 474
 475    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 476       png_read_start_row(png_ptr);
 477    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
 478    {
 479    /* Check for transforms that have been set but were defined out */
 480 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
 481    if (png_ptr->transformations & PNG_INVERT_MONO)
 482       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
 483 #endif
 484 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
 485    if (png_ptr->transformations & PNG_FILLER)
 486       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
 487 #endif
 488 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
 489     !defined(PNG_READ_PACKSWAP_SUPPORTED)
 490    if (png_ptr->transformations & PNG_PACKSWAP)
 491       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
 492 #endif
 493 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
 494    if (png_ptr->transformations & PNG_PACK)
 495       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
 496 #endif
 497 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
 498    if (png_ptr->transformations & PNG_SHIFT)
 499       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
 500 #endif
 501 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
 502    if (png_ptr->transformations & PNG_BGR)
 503       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
 504 #endif
 505 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
 506    if (png_ptr->transformations & PNG_SWAP_BYTES)
 507       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
 508 #endif
 509    }
 510
 511 #ifdef PNG_READ_INTERLACING_SUPPORTED
 512    /* If interlaced and we do not need a new row, combine row and return */
 513    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 514    {
 515       switch (png_ptr->pass)
 516       {
 517          case 0:
 518             if (png_ptr->row_number & 0x07)
 519             {
 520                if (dsp_row != NULL)
 521                   png_combine_row(png_ptr, dsp_row,
 522                      png_pass_dsp_mask[png_ptr->pass]);
 523                png_read_finish_row(png_ptr);
 524                return;
 525             }
 526             break;
 527          case 1:
 528             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
 529             {
 530                if (dsp_row != NULL)
 531                   png_combine_row(png_ptr, dsp_row,
 532                      png_pass_dsp_mask[png_ptr->pass]);
 533                png_read_finish_row(png_ptr);
 534                return;
 535             }
 536             break;
 537          case 2:
 538             if ((png_ptr->row_number & 0x07) != 4)
 539             {
 540                if (dsp_row != NULL && (png_ptr->row_number & 4))
 541                   png_combine_row(png_ptr, dsp_row,
 542                      png_pass_dsp_mask[png_ptr->pass]);
 543                png_read_finish_row(png_ptr);
 544                return;
 545             }
 546             break;
 547          case 3:
 548             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
 549             {
 550                if (dsp_row != NULL)
 551                   png_combine_row(png_ptr, dsp_row,
 552                      png_pass_dsp_mask[png_ptr->pass]);
 553                png_read_finish_row(png_ptr);
 554                return;
 555             }
 556             break;
 557          case 4:
 558             if ((png_ptr->row_number & 3) != 2)
 559             {
 560                if (dsp_row != NULL && (png_ptr->row_number & 2))
 561                   png_combine_row(png_ptr, dsp_row,
 562                      png_pass_dsp_mask[png_ptr->pass]);
 563                png_read_finish_row(png_ptr);
 564                return;
 565             }
 566             break;
 567          case 5:
 568             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
 569             {
 570                if (dsp_row != NULL)
 571                   png_combine_row(png_ptr, dsp_row,
 572                      png_pass_dsp_mask[png_ptr->pass]);
 573                png_read_finish_row(png_ptr);
 574                return;
 575             }
 576             break;
 577          case 6:
 578             if (!(png_ptr->row_number & 1))
 579             {
 580                png_read_finish_row(png_ptr);
 581                return;
 582             }
 583             break;
 584       }
 585    }
 586 #endif
 587
 588    if (!(png_ptr->mode & PNG_HAVE_IDAT))
 589       png_error(png_ptr, "Invalid attempt to read row data");
 590
 591    png_ptr->zstream.next_out = png_ptr->row_buf;
 592    png_ptr->zstream.avail_out =
 593        (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
 594        png_ptr->iwidth) + 1);
 595    do
 596    {
 597       if (!(png_ptr->zstream.avail_in))
 598       {
 599          while (!png_ptr->idat_size)
 600          {
 601             png_crc_finish(png_ptr, 0);
 602
 603             png_ptr->idat_size = png_read_chunk_header(png_ptr);
 604             if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 605                png_error(png_ptr, "Not enough image data");
 606          }
 607          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
 608          png_ptr->zstream.next_in = png_ptr->zbuf;
 609          if (png_ptr->zbuf_size > png_ptr->idat_size)
 610             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
 611          png_crc_read(png_ptr, png_ptr->zbuf,
 612             (png_size_t)png_ptr->zstream.avail_in);
 613          png_ptr->idat_size -= png_ptr->zstream.avail_in;
 614       }
 615       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 616       if (ret == Z_STREAM_END)
 617       {
 618          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
 619             png_ptr->idat_size)
 620             png_benign_error(png_ptr, "Extra compressed data");
 621          png_ptr->mode |= PNG_AFTER_IDAT;
 622          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 623          break;
 624       }
 625       if (ret != Z_OK)
 626          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
 627                    "Decompression error");
 628
 629    } while (png_ptr->zstream.avail_out);
 630
 631    png_ptr->row_info.color_type = png_ptr->color_type;
 632    png_ptr->row_info.width = png_ptr->iwidth;
 633    png_ptr->row_info.channels = png_ptr->channels;
 634    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 635    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 636    png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
 637        png_ptr->row_info.width);
 638
 639    if (png_ptr->row_buf[0])
 640    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 641       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 642       (int)(png_ptr->row_buf[0]));
 643
 644    png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
 645
 646 #ifdef PNG_MNG_FEATURES_SUPPORTED
 647    if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
 648       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
 649    {
 650       /* Intrapixel differencing */
 651       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
 652    }
 653 #endif
 654
 655
 656    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
 657       png_do_read_transformations(png_ptr);
 658
 659 #ifdef PNG_READ_INTERLACING_SUPPORTED
 660    /* Blow up interlaced rows to full size */
 661    if (png_ptr->interlaced &&
 662       (png_ptr->transformations & PNG_INTERLACE))
 663    {
 664       if (png_ptr->pass < 6)
 665          /* Old interface (pre-1.0.9):
 666           * png_do_read_interlace(&(png_ptr->row_info),
 667           *    png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 668           */
 669          png_do_read_interlace(png_ptr);
 670
 671       if (dsp_row != NULL)
 672          png_combine_row(png_ptr, dsp_row,
 673             png_pass_dsp_mask[png_ptr->pass]);
 674       if (row != NULL)
 675          png_combine_row(png_ptr, row,
 676             png_pass_mask[png_ptr->pass]);
 677    }
 678    else
 679 #endif
 680    {
 681       if (row != NULL)
 682          png_combine_row(png_ptr, row, 0xff);
 683       if (dsp_row != NULL)
 684          png_combine_row(png_ptr, dsp_row, 0xff);
 685    }
 686    png_read_finish_row(png_ptr);
 687
 688    if (png_ptr->read_row_fn != NULL)
 689       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
 690 }
 691 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 692
 693 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 694 /* Read one or more rows of image data.  If the image is interlaced,
 695  * and png_set_interlace_handling() has been called, the rows need to
 696  * contain the contents of the rows from the previous pass.  If the
 697  * image has alpha or transparency, and png_handle_alpha()[*] has been
 698  * called, the rows contents must be initialized to the contents of the
 699  * screen.
 700  *
 701  * "row" holds the actual image, and pixels are placed in it
 702  * as they arrive.  If the image is displayed after each pass, it will
 703  * appear to "sparkle" in.  "display_row" can be used to display a
 704  * "chunky" progressive image, with finer detail added as it becomes
 705  * available.  If you do not want this "chunky" display, you may pass
 706  * NULL for display_row.  If you do not want the sparkle display, and
 707  * you have not called png_handle_alpha(), you may pass NULL for rows.
 708  * If you have called png_handle_alpha(), and the image has either an
 709  * alpha channel or a transparency chunk, you must provide a buffer for
 710  * rows.  In this case, you do not have to provide a display_row buffer
 711  * also, but you may.  If the image is not interlaced, or if you have
 712  * not called png_set_interlace_handling(), the display_row buffer will
 713  * be ignored, so pass NULL to it.
 714  *
 715  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 716  */
 717
 718 void PNGAPI
 719 png_read_rows(png_structp png_ptr, png_bytepp row,
 720    png_bytepp display_row, png_uint_32 num_rows)
 721 {
 722    png_uint_32 i;
 723    png_bytepp rp;
 724    png_bytepp dp;
 725
 726    png_debug(1, "in png_read_rows");
 727
 728    if (png_ptr == NULL)
 729       return;
 730    rp = row;
 731    dp = display_row;
 732    if (rp != NULL && dp != NULL)
 733       for (i = 0; i < num_rows; i++)
 734       {
 735          png_bytep rptr = *rp++;
 736          png_bytep dptr = *dp++;
 737
 738          png_read_row(png_ptr, rptr, dptr);
 739       }
 740    else if (rp != NULL)
 741       for (i = 0; i < num_rows; i++)
 742       {
 743          png_bytep rptr = *rp;
 744          png_read_row(png_ptr, rptr, NULL);
 745          rp++;
 746       }
 747    else if (dp != NULL)
 748       for (i = 0; i < num_rows; i++)
 749       {
 750          png_bytep dptr = *dp;
 751          png_read_row(png_ptr, NULL, dptr);
 752          dp++;
 753       }
 754 }
 755 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 756
 757 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 758 /* Read the entire image.  If the image has an alpha channel or a tRNS
 759  * chunk, and you have called png_handle_alpha()[*], you will need to
 760  * initialize the image to the current image that PNG will be overlaying.
 761  * We set the num_rows again here, in case it was incorrectly set in
 762  * png_read_start_row() by a call to png_read_update_info() or
 763  * png_start_read_image() if png_set_interlace_handling() wasn't called
 764  * prior to either of these functions like it should have been.  You can
 765  * only call this function once.  If you desire to have an image for
 766  * each pass of a interlaced image, use png_read_rows() instead.
 767  *
 768  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 769  */
 770 void PNGAPI
 771 png_read_image(png_structp png_ptr, png_bytepp image)
 772 {
 773    png_uint_32 i, image_height;
 774    int pass, j;
 775    png_bytepp rp;
 776
 777    png_debug(1, "in png_read_image");
 778
 779    if (png_ptr == NULL)
 780       return;
 781
 782 #ifdef PNG_READ_INTERLACING_SUPPORTED
 783    pass = png_set_interlace_handling(png_ptr);
 784 #else
 785    if (png_ptr->interlaced)
 786       png_error(png_ptr,
 787         "Cannot read interlaced image -- interlace handler disabled");
 788    pass = 1;
 789 #endif
 790
 791
 792    image_height=png_ptr->height;
 793    png_ptr->num_rows = image_height; /* Make sure this is set correctly */
 794
 795    for (j = 0; j < pass; j++)
 796    {
 797       rp = image;
 798       for (i = 0; i < image_height; i++)
 799       {
 800          png_read_row(png_ptr, *rp, NULL);
 801          rp++;
 802       }
 803    }
 804 }
 805 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 806
 807 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 808 /* Read the end of the PNG file.  Will not read past the end of the
 809  * file, will verify the end is accurate, and will read any comments
 810  * or time information at the end of the file, if info is not NULL.
 811  */
 812 void PNGAPI
 813 png_read_end(png_structp png_ptr, png_infop info_ptr)
 814 {
 815    png_debug(1, "in png_read_end");
 816
 817    if (png_ptr == NULL)
 818       return;
 819    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 820
 821    do
 822    {
 823       PNG_IHDR;
 824       PNG_IDAT;
 825       PNG_IEND;
 826       PNG_PLTE;
 827 #ifdef PNG_READ_bKGD_SUPPORTED
 828       PNG_bKGD;
 829 #endif
 830 #ifdef PNG_READ_cHRM_SUPPORTED
 831       PNG_cHRM;
 832 #endif
 833 #ifdef PNG_READ_gAMA_SUPPORTED
 834       PNG_gAMA;
 835 #endif
 836 #ifdef PNG_READ_hIST_SUPPORTED
 837       PNG_hIST;
 838 #endif
 839 #ifdef PNG_READ_iCCP_SUPPORTED
 840       PNG_iCCP;
 841 #endif
 842 #ifdef PNG_READ_iTXt_SUPPORTED
 843       PNG_iTXt;
 844 #endif
 845 #ifdef PNG_READ_oFFs_SUPPORTED
 846       PNG_oFFs;
 847 #endif
 848 #ifdef PNG_READ_pCAL_SUPPORTED
 849       PNG_pCAL;
 850 #endif
 851 #ifdef PNG_READ_pHYs_SUPPORTED
 852       PNG_pHYs;
 853 #endif
 854 #ifdef PNG_READ_sBIT_SUPPORTED
 855       PNG_sBIT;
 856 #endif
 857 #ifdef PNG_READ_sCAL_SUPPORTED
 858       PNG_sCAL;
 859 #endif
 860 #ifdef PNG_READ_sPLT_SUPPORTED
 861       PNG_sPLT;
 862 #endif
 863 #ifdef PNG_READ_sRGB_SUPPORTED
 864       PNG_sRGB;
 865 #endif
 866 #ifdef PNG_READ_tEXt_SUPPORTED
 867       PNG_tEXt;
 868 #endif
 869 #ifdef PNG_READ_tIME_SUPPORTED
 870       PNG_tIME;
 871 #endif
 872 #ifdef PNG_READ_tRNS_SUPPORTED
 873       PNG_tRNS;
 874 #endif
 875 #ifdef PNG_READ_zTXt_SUPPORTED
 876       PNG_zTXt;
 877 #endif
 878       png_uint_32 length = png_read_chunk_header(png_ptr);
 879       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
 880
 881       if (!png_memcmp(chunk_name, png_IHDR, 4))
 882          png_handle_IHDR(png_ptr, info_ptr, length);
 883       else if (!png_memcmp(chunk_name, png_IEND, 4))
 884          png_handle_IEND(png_ptr, info_ptr, length);
 885 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 886       else if (png_handle_as_unknown(png_ptr, chunk_name))
 887       {
 888          if (!png_memcmp(chunk_name, png_IDAT, 4))
 889          {
 890             if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 891                png_benign_error(png_ptr, "Too many IDATs found");
 892          }
 893          png_handle_unknown(png_ptr, info_ptr, length);
 894          if (!png_memcmp(chunk_name, png_PLTE, 4))
 895             png_ptr->mode |= PNG_HAVE_PLTE;
 896       }
 897 #endif
 898       else if (!png_memcmp(chunk_name, png_IDAT, 4))
 899       {
 900          /* Zero length IDATs are legal after the last IDAT has been
 901           * read, but not after other chunks have been read.
 902           */
 903          if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 904             png_benign_error(png_ptr, "Too many IDATs found");
 905          png_crc_finish(png_ptr, length);
 906       }
 907       else if (!png_memcmp(chunk_name, png_PLTE, 4))
 908          png_handle_PLTE(png_ptr, info_ptr, length);
 909 #ifdef PNG_READ_bKGD_SUPPORTED
 910       else if (!png_memcmp(chunk_name, png_bKGD, 4))
 911          png_handle_bKGD(png_ptr, info_ptr, length);
 912 #endif
 913 #ifdef PNG_READ_cHRM_SUPPORTED
 914       else if (!png_memcmp(chunk_name, png_cHRM, 4))
 915          png_handle_cHRM(png_ptr, info_ptr, length);
 916 #endif
 917 #ifdef PNG_READ_gAMA_SUPPORTED
 918       else if (!png_memcmp(chunk_name, png_gAMA, 4))
 919          png_handle_gAMA(png_ptr, info_ptr, length);
 920 #endif
 921 #ifdef PNG_READ_hIST_SUPPORTED
 922       else if (!png_memcmp(chunk_name, png_hIST, 4))
 923          png_handle_hIST(png_ptr, info_ptr, length);
 924 #endif
 925 #ifdef PNG_READ_oFFs_SUPPORTED
 926       else if (!png_memcmp(chunk_name, png_oFFs, 4))
 927          png_handle_oFFs(png_ptr, info_ptr, length);
 928 #endif
 929 #ifdef PNG_READ_pCAL_SUPPORTED
 930       else if (!png_memcmp(chunk_name, png_pCAL, 4))
 931          png_handle_pCAL(png_ptr, info_ptr, length);
 932 #endif
 933 #ifdef PNG_READ_sCAL_SUPPORTED
 934       else if (!png_memcmp(chunk_name, png_sCAL, 4))
 935          png_handle_sCAL(png_ptr, info_ptr, length);
 936 #endif
 937 #ifdef PNG_READ_pHYs_SUPPORTED
 938       else if (!png_memcmp(chunk_name, png_pHYs, 4))
 939          png_handle_pHYs(png_ptr, info_ptr, length);
 940 #endif
 941 #ifdef PNG_READ_sBIT_SUPPORTED
 942       else if (!png_memcmp(chunk_name, png_sBIT, 4))
 943          png_handle_sBIT(png_ptr, info_ptr, length);
 944 #endif
 945 #ifdef PNG_READ_sRGB_SUPPORTED
 946       else if (!png_memcmp(chunk_name, png_sRGB, 4))
 947          png_handle_sRGB(png_ptr, info_ptr, length);
 948 #endif
 949 #ifdef PNG_READ_iCCP_SUPPORTED
 950       else if (!png_memcmp(chunk_name, png_iCCP, 4))
 951          png_handle_iCCP(png_ptr, info_ptr, length);
 952 #endif
 953 #ifdef PNG_READ_sPLT_SUPPORTED
 954       else if (!png_memcmp(chunk_name, png_sPLT, 4))
 955          png_handle_sPLT(png_ptr, info_ptr, length);
 956 #endif
 957 #ifdef PNG_READ_tEXt_SUPPORTED
 958       else if (!png_memcmp(chunk_name, png_tEXt, 4))
 959          png_handle_tEXt(png_ptr, info_ptr, length);
 960 #endif
 961 #ifdef PNG_READ_tIME_SUPPORTED
 962       else if (!png_memcmp(chunk_name, png_tIME, 4))
 963          png_handle_tIME(png_ptr, info_ptr, length);
 964 #endif
 965 #ifdef PNG_READ_tRNS_SUPPORTED
 966       else if (!png_memcmp(chunk_name, png_tRNS, 4))
 967          png_handle_tRNS(png_ptr, info_ptr, length);
 968 #endif
 969 #ifdef PNG_READ_zTXt_SUPPORTED
 970       else if (!png_memcmp(chunk_name, png_zTXt, 4))
 971          png_handle_zTXt(png_ptr, info_ptr, length);
 972 #endif
 973 #ifdef PNG_READ_iTXt_SUPPORTED
 974       else if (!png_memcmp(chunk_name, png_iTXt, 4))
 975          png_handle_iTXt(png_ptr, info_ptr, length);
 976 #endif
 977       else
 978          png_handle_unknown(png_ptr, info_ptr, length);
 979    } while (!(png_ptr->mode & PNG_HAVE_IEND));
 980 }
 981 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 982
 983 /* Free all memory used by the read */
 984 void PNGAPI
 985 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
 986    png_infopp end_info_ptr_ptr)
 987 {
 988    png_structp png_ptr = NULL;
 989    png_infop info_ptr = NULL, end_info_ptr = NULL;
 990 #ifdef PNG_USER_MEM_SUPPORTED
 991    png_free_ptr free_fn = NULL;
 992    png_voidp mem_ptr = NULL;
 993 #endif
 994
 995    png_debug(1, "in png_destroy_read_struct");
 996
 997    if (png_ptr_ptr != NULL)
 998       png_ptr = *png_ptr_ptr;
 999    if (png_ptr == NULL)
1000       return;
1001
1002 #ifdef PNG_USER_MEM_SUPPORTED
1003    free_fn = png_ptr->free_fn;
1004    mem_ptr = png_ptr->mem_ptr;
1005 #endif
1006
1007    if (info_ptr_ptr != NULL)
1008       info_ptr = *info_ptr_ptr;
1009
1010    if (end_info_ptr_ptr != NULL)
1011       end_info_ptr = *end_info_ptr_ptr;
1012
1013    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1014
1015    if (info_ptr != NULL)
1016    {
1017 #ifdef PNG_TEXT_SUPPORTED
1018       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1019 #endif
1020
1021 #ifdef PNG_USER_MEM_SUPPORTED
1022       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1023           (png_voidp)mem_ptr);
1024 #else
1025       png_destroy_struct((png_voidp)info_ptr);
1026 #endif
1027       *info_ptr_ptr = NULL;
1028    }
1029
1030    if (end_info_ptr != NULL)
1031    {
1032 #ifdef PNG_READ_TEXT_SUPPORTED
1033       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1034 #endif
1035 #ifdef PNG_USER_MEM_SUPPORTED
1036       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1037          (png_voidp)mem_ptr);
1038 #else
1039       png_destroy_struct((png_voidp)end_info_ptr);
1040 #endif
1041       *end_info_ptr_ptr = NULL;
1042    }
1043
1044    if (png_ptr != NULL)
1045    {
1046 #ifdef PNG_USER_MEM_SUPPORTED
1047       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1048           (png_voidp)mem_ptr);
1049 #else
1050       png_destroy_struct((png_voidp)png_ptr);
1051 #endif
1052       *png_ptr_ptr = NULL;
1053    }
1054 }
1055
1056 /* Free all memory used by the read (old method) */
1057 void /* PRIVATE */
1058 png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1059     png_infop end_info_ptr)
1060 {
1061 #ifdef PNG_SETJMP_SUPPORTED
1062    jmp_buf tmp_jmp;
1063 #endif
1064    png_error_ptr error_fn;
1065    png_error_ptr warning_fn;
1066    png_voidp error_ptr;
1067 #ifdef PNG_USER_MEM_SUPPORTED
1068    png_free_ptr free_fn;
1069 #endif
1070
1071    png_debug(1, "in png_read_destroy");
1072
1073    if (info_ptr != NULL)
1074       png_info_destroy(png_ptr, info_ptr);
1075
1076    if (end_info_ptr != NULL)
1077       png_info_destroy(png_ptr, end_info_ptr);
1078
1079    png_free(png_ptr, png_ptr->zbuf);
1080    png_free(png_ptr, png_ptr->big_row_buf);
1081    png_free(png_ptr, png_ptr->prev_row);
1082    png_free(png_ptr, png_ptr->chunkdata);
1083 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1084    png_free(png_ptr, png_ptr->palette_lookup);
1085    png_free(png_ptr, png_ptr->quantize_index);
1086 #endif
1087 #ifdef PNG_READ_GAMMA_SUPPORTED
1088    png_free(png_ptr, png_ptr->gamma_table);
1089 #endif
1090 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1091    png_free(png_ptr, png_ptr->gamma_from_1);
1092    png_free(png_ptr, png_ptr->gamma_to_1);
1093 #endif
1094    if (png_ptr->free_me & PNG_FREE_PLTE)
1095       png_zfree(png_ptr, png_ptr->palette);
1096    png_ptr->free_me &= ~PNG_FREE_PLTE;
1097 #if defined(PNG_tRNS_SUPPORTED) || \
1098     defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1099    if (png_ptr->free_me & PNG_FREE_TRNS)
1100       png_free(png_ptr, png_ptr->trans_alpha);
1101    png_ptr->free_me &= ~PNG_FREE_TRNS;
1102 #endif
1103 #ifdef PNG_READ_hIST_SUPPORTED
1104    if (png_ptr->free_me & PNG_FREE_HIST)
1105       png_free(png_ptr, png_ptr->hist);
1106    png_ptr->free_me &= ~PNG_FREE_HIST;
1107 #endif
1108 #ifdef PNG_READ_GAMMA_SUPPORTED
1109    if (png_ptr->gamma_16_table != NULL)
1110    {
1111       int i;
1112       int istop = (1 << (8 - png_ptr->gamma_shift));
1113       for (i = 0; i < istop; i++)
1114       {
1115          png_free(png_ptr, png_ptr->gamma_16_table[i]);
1116       }
1117    png_free(png_ptr, png_ptr->gamma_16_table);
1118    }
1119 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1120    if (png_ptr->gamma_16_from_1 != NULL)
1121    {
1122       int i;
1123       int istop = (1 << (8 - png_ptr->gamma_shift));
1124       for (i = 0; i < istop; i++)
1125       {
1126          png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1127       }
1128    png_free(png_ptr, png_ptr->gamma_16_from_1);
1129    }
1130    if (png_ptr->gamma_16_to_1 != NULL)
1131    {
1132       int i;
1133       int istop = (1 << (8 - png_ptr->gamma_shift));
1134       for (i = 0; i < istop; i++)
1135       {
1136          png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1137       }
1138    png_free(png_ptr, png_ptr->gamma_16_to_1);
1139    }
1140 #endif
1141 #endif
1142 #ifdef PNG_TIME_RFC1123_SUPPORTED
1143    png_free(png_ptr, png_ptr->time_buffer);
1144 #endif
1145
1146    inflateEnd(&png_ptr->zstream);
1147 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1148    png_free(png_ptr, png_ptr->save_buffer);
1149 #endif
1150
1151 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1152 #ifdef PNG_TEXT_SUPPORTED
1153    png_free(png_ptr, png_ptr->current_text);
1154 #endif /* PNG_TEXT_SUPPORTED */
1155 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1156
1157    /* Save the important info out of the png_struct, in case it is
1158     * being used again.
1159     */
1160 #ifdef PNG_SETJMP_SUPPORTED
1161    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
1162 #endif
1163
1164    error_fn = png_ptr->error_fn;
1165    warning_fn = png_ptr->warning_fn;
1166    error_ptr = png_ptr->error_ptr;
1167 #ifdef PNG_USER_MEM_SUPPORTED
1168    free_fn = png_ptr->free_fn;
1169 #endif
1170
1171    png_memset(png_ptr, 0, png_sizeof(png_struct));
1172
1173    png_ptr->error_fn = error_fn;
1174    png_ptr->warning_fn = warning_fn;
1175    png_ptr->error_ptr = error_ptr;
1176 #ifdef PNG_USER_MEM_SUPPORTED
1177    png_ptr->free_fn = free_fn;
1178 #endif
1179
1180 #ifdef PNG_SETJMP_SUPPORTED
1181    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
1182 #endif
1183
1184 }
1185
1186 void PNGAPI
1187 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1188 {
1189    if (png_ptr == NULL)
1190       return;
1191    png_ptr->read_row_fn = read_row_fn;
1192 }
1193
1194
1195 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1196 #ifdef PNG_INFO_IMAGE_SUPPORTED
1197 void PNGAPI
1198 png_read_png(png_structp png_ptr, png_infop info_ptr,
1199                            int transforms,
1200                            voidp params)
1201 {
1202    int row;
1203
1204    if (png_ptr == NULL)
1205       return;
1206
1207    /* png_read_info() gives us all of the information from the
1208     * PNG file before the first IDAT (image data chunk).
1209     */
1210    png_read_info(png_ptr, info_ptr);
1211    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1212       png_error(png_ptr, "Image is too high to process with png_read_png()");
1213
1214    /* -------------- image transformations start here ------------------- */
1215
1216 #ifdef PNG_READ_16_TO_8_SUPPORTED
1217    /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
1218     */
1219    if (transforms & PNG_TRANSFORM_STRIP_16)
1220       png_set_strip_16(png_ptr);
1221 #endif
1222
1223 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1224    /* Strip alpha bytes from the input data without combining with
1225     * the background (not recommended).
1226     */
1227    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1228       png_set_strip_alpha(png_ptr);
1229 #endif
1230
1231 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1232    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1233     * byte into separate bytes (useful for paletted and grayscale images).
1234     */
1235    if (transforms & PNG_TRANSFORM_PACKING)
1236       png_set_packing(png_ptr);
1237 #endif
1238
1239 #ifdef PNG_READ_PACKSWAP_SUPPORTED
1240    /* Change the order of packed pixels to least significant bit first
1241     * (not useful if you are using png_set_packing).
1242     */
1243    if (transforms & PNG_TRANSFORM_PACKSWAP)
1244       png_set_packswap(png_ptr);
1245 #endif
1246
1247 #ifdef PNG_READ_EXPAND_SUPPORTED
1248    /* Expand paletted colors into true RGB triplets
1249     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1250     * Expand paletted or RGB images with transparency to full alpha
1251     * channels so the data will be available as RGBA quartets.
1252     */
1253    if (transforms & PNG_TRANSFORM_EXPAND)
1254       if ((png_ptr->bit_depth < 8) ||
1255           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1256           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1257          png_set_expand(png_ptr);
1258 #endif
1259
1260    /* We don't handle background color or gamma transformation or quantizing.
1261     */
1262
1263 #ifdef PNG_READ_INVERT_SUPPORTED
1264    /* Invert monochrome files to have 0 as white and 1 as black
1265     */
1266    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1267       png_set_invert_mono(png_ptr);
1268 #endif
1269
1270 #ifdef PNG_READ_SHIFT_SUPPORTED
1271    /* If you want to shift the pixel values from the range [0,255] or
1272     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1273     * colors were originally in:
1274     */
1275    if ((transforms & PNG_TRANSFORM_SHIFT)
1276        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1277    {
1278       png_color_8p sig_bit;
1279
1280       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1281       png_set_shift(png_ptr, sig_bit);
1282    }
1283 #endif
1284
1285 #ifdef PNG_READ_BGR_SUPPORTED
1286    /* Flip the RGB pixels to BGR (or RGBA to BGRA)
1287     */
1288    if (transforms & PNG_TRANSFORM_BGR)
1289       png_set_bgr(png_ptr);
1290 #endif
1291
1292 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1293    /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1294     */
1295    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1296        png_set_swap_alpha(png_ptr);
1297 #endif
1298
1299 #ifdef PNG_READ_SWAP_SUPPORTED
1300    /* Swap bytes of 16 bit files to least significant byte first
1301     */
1302    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1303       png_set_swap(png_ptr);
1304 #endif
1305
1306 /* Added at libpng-1.2.41 */
1307 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1308    /* Invert the alpha channel from opacity to transparency
1309     */
1310    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1311        png_set_invert_alpha(png_ptr);
1312 #endif
1313
1314 /* Added at libpng-1.2.41 */
1315 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1316    /* Expand grayscale image to RGB
1317     */
1318    if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1319        png_set_gray_to_rgb(png_ptr);
1320 #endif
1321
1322    /* We don't handle adding filler bytes */
1323
1324    /* Optional call to gamma correct and add the background to the palette
1325     * and update info structure.  REQUIRED if you are expecting libpng to
1326     * update the palette for you (i.e., you selected such a transform above).
1327     */
1328    png_read_update_info(png_ptr, info_ptr);
1329
1330    /* -------------- image transformations end here ------------------- */
1331
1332    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1333    if (info_ptr->row_pointers == NULL)
1334    {
1335     png_uint_32 iptr;
1336
1337       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1338          info_ptr->height * png_sizeof(png_bytep));
1339       for (iptr=0; iptr<info_ptr->height; iptr++)
1340          info_ptr->row_pointers[iptr] = NULL;
1341
1342       info_ptr->free_me |= PNG_FREE_ROWS;
1343
1344       for (row = 0; row < (int)info_ptr->height; row++)
1345          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1346             png_get_rowbytes(png_ptr, info_ptr));
1347    }
1348
1349    png_read_image(png_ptr, info_ptr->row_pointers);
1350    info_ptr->valid |= PNG_INFO_IDAT;
1351
1352    /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1353    png_read_end(png_ptr, info_ptr);
1354
1355    transforms = transforms; /* Quiet compiler warnings */
1356    params = params;
1357
1358 }
1359 #endif /* PNG_INFO_IMAGE_SUPPORTED */
1360 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1361 #endif /* PNG_READ_SUPPORTED */