reactos/dll/3rdparty/libpng/pngread.c

   1
   2 /* pngread.c - read a PNG file
   3  *
   4  * Last changed in libpng 1.5.10 [March 8, 2012]
   5  * Copyright (c) 1998-2012 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 tmp_jmpbuf;
  51 #endif
  52 #endif
  53
  54    png_debug(1, "in png_create_read_struct");
  55
  56 #ifdef PNG_USER_MEM_SUPPORTED
  57    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
  58        malloc_fn, mem_ptr);
  59 #else
  60    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
  61 #endif
  62    if (png_ptr == NULL)
  63       return (NULL);
  64
  65    /* Added at libpng-1.2.6 */
  66 #ifdef PNG_USER_LIMITS_SUPPORTED
  67    png_ptr->user_width_max = PNG_USER_WIDTH_MAX;
  68    png_ptr->user_height_max = PNG_USER_HEIGHT_MAX;
  69
  70    /* Added at libpng-1.2.43 and 1.4.0 */
  71    png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
  72
  73    /* Added at libpng-1.2.43 and 1.4.1 */
  74    png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
  75 #endif
  76
  77 #ifdef PNG_SETJMP_SUPPORTED
  78 /* Applications that neglect to set up their own setjmp() and then
  79  * encounter a png_error() will longjmp here.  Since the jmpbuf is
  80  * then meaningless we abort instead of returning.
  81  */
  82 #ifdef USE_FAR_KEYWORD
  83    if (setjmp(tmp_jmpbuf))
  84 #else
  85    if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
  86 #endif
  87       PNG_ABORT();
  88 #ifdef USE_FAR_KEYWORD
  89    png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
  90 #endif
  91 #endif /* PNG_SETJMP_SUPPORTED */
  92
  93 #ifdef PNG_USER_MEM_SUPPORTED
  94    png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
  95 #endif
  96
  97    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
  98
  99    /* Call the general version checker (shared with read and write code): */
 100    if (!png_user_version_check(png_ptr, user_png_ver))
 101       png_cleanup_needed = 1;
 102
 103    if (!png_cleanup_needed)
 104    {
 105    /* Initialize zbuf - compression buffer */
 106    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 107    png_ptr->zbuf = (png_bytep)png_malloc_warn(png_ptr, png_ptr->zbuf_size);
 108
 109    if (png_ptr->zbuf == NULL)
 110       png_cleanup_needed = 1;
 111    }
 112
 113    png_ptr->zstream.zalloc = png_zalloc;
 114    png_ptr->zstream.zfree = png_zfree;
 115    png_ptr->zstream.opaque = (voidpf)png_ptr;
 116
 117    if (!png_cleanup_needed)
 118    {
 119       switch (inflateInit(&png_ptr->zstream))
 120       {
 121          case Z_OK:
 122             break; /* Do nothing */
 123
 124          case Z_MEM_ERROR:
 125             png_warning(png_ptr, "zlib memory error");
 126             png_cleanup_needed = 1;
 127             break;
 128
 129          case Z_STREAM_ERROR:
 130             png_warning(png_ptr, "zlib stream error");
 131             png_cleanup_needed = 1;
 132             break;
 133
 134          case Z_VERSION_ERROR:
 135             png_warning(png_ptr, "zlib version error");
 136             png_cleanup_needed = 1;
 137             break;
 138
 139          default: png_warning(png_ptr, "Unknown zlib error");
 140             png_cleanup_needed = 1;
 141       }
 142    }
 143
 144    if (png_cleanup_needed)
 145    {
 146       /* Clean up PNG structure and deallocate any memory. */
 147       png_free(png_ptr, png_ptr->zbuf);
 148       png_ptr->zbuf = NULL;
 149 #ifdef PNG_USER_MEM_SUPPORTED
 150       png_destroy_struct_2((png_voidp)png_ptr,
 151           (png_free_ptr)free_fn, (png_voidp)mem_ptr);
 152 #else
 153       png_destroy_struct((png_voidp)png_ptr);
 154 #endif
 155       return (NULL);
 156    }
 157
 158    png_ptr->zstream.next_out = png_ptr->zbuf;
 159    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 160
 161    png_set_read_fn(png_ptr, NULL, NULL);
 162
 163
 164    return (png_ptr);
 165 }
 166
 167
 168 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 169 /* Read the information before the actual image data.  This has been
 170  * changed in v0.90 to allow reading a file that already has the magic
 171  * bytes read from the stream.  You can tell libpng how many bytes have
 172  * been read from the beginning of the stream (up to the maximum of 8)
 173  * via png_set_sig_bytes(), and we will only check the remaining bytes
 174  * here.  The application can then have access to the signature bytes we
 175  * read if it is determined that this isn't a valid PNG file.
 176  */
 177 void PNGAPI
 178 png_read_info(png_structp png_ptr, png_infop info_ptr)
 179 {
 180    png_debug(1, "in png_read_info");
 181
 182    if (png_ptr == NULL || info_ptr == NULL)
 183       return;
 184
 185    /* Read and check the PNG file signature. */
 186    png_read_sig(png_ptr, info_ptr);
 187
 188    for (;;)
 189    {
 190       png_uint_32 length = png_read_chunk_header(png_ptr);
 191       png_uint_32 chunk_name = png_ptr->chunk_name;
 192
 193       /* This should be a binary subdivision search or a hash for
 194        * matching the chunk name rather than a linear search.
 195        */
 196       if (chunk_name == png_IDAT)
 197          if (png_ptr->mode & PNG_AFTER_IDAT)
 198             png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 199
 200       if (chunk_name == png_IHDR)
 201          png_handle_IHDR(png_ptr, info_ptr, length);
 202
 203       else if (chunk_name == png_IEND)
 204          png_handle_IEND(png_ptr, info_ptr, length);
 205
 206 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 207       else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
 208          PNG_HANDLE_CHUNK_AS_DEFAULT)
 209       {
 210          if (chunk_name == png_IDAT)
 211             png_ptr->mode |= PNG_HAVE_IDAT;
 212
 213          png_handle_unknown(png_ptr, info_ptr, length);
 214
 215          if (chunk_name == png_PLTE)
 216             png_ptr->mode |= PNG_HAVE_PLTE;
 217
 218          else if (chunk_name == png_IDAT)
 219          {
 220             if (!(png_ptr->mode & PNG_HAVE_IHDR))
 221                png_error(png_ptr, "Missing IHDR before IDAT");
 222
 223             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 224                 !(png_ptr->mode & PNG_HAVE_PLTE))
 225                png_error(png_ptr, "Missing PLTE before IDAT");
 226
 227             break;
 228          }
 229       }
 230 #endif
 231       else if (chunk_name == png_PLTE)
 232          png_handle_PLTE(png_ptr, info_ptr, length);
 233
 234       else if (chunk_name == png_IDAT)
 235       {
 236          if (!(png_ptr->mode & PNG_HAVE_IHDR))
 237             png_error(png_ptr, "Missing IHDR before IDAT");
 238
 239          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 240              !(png_ptr->mode & PNG_HAVE_PLTE))
 241             png_error(png_ptr, "Missing PLTE before IDAT");
 242
 243          png_ptr->idat_size = length;
 244          png_ptr->mode |= PNG_HAVE_IDAT;
 245          break;
 246       }
 247
 248 #ifdef PNG_READ_bKGD_SUPPORTED
 249       else if (chunk_name == png_bKGD)
 250          png_handle_bKGD(png_ptr, info_ptr, length);
 251 #endif
 252
 253 #ifdef PNG_READ_cHRM_SUPPORTED
 254       else if (chunk_name == png_cHRM)
 255          png_handle_cHRM(png_ptr, info_ptr, length);
 256 #endif
 257
 258 #ifdef PNG_READ_gAMA_SUPPORTED
 259       else if (chunk_name == png_gAMA)
 260          png_handle_gAMA(png_ptr, info_ptr, length);
 261 #endif
 262
 263 #ifdef PNG_READ_hIST_SUPPORTED
 264       else if (chunk_name == png_hIST)
 265          png_handle_hIST(png_ptr, info_ptr, length);
 266 #endif
 267
 268 #ifdef PNG_READ_oFFs_SUPPORTED
 269       else if (chunk_name == png_oFFs)
 270          png_handle_oFFs(png_ptr, info_ptr, length);
 271 #endif
 272
 273 #ifdef PNG_READ_pCAL_SUPPORTED
 274       else if (chunk_name == png_pCAL)
 275          png_handle_pCAL(png_ptr, info_ptr, length);
 276 #endif
 277
 278 #ifdef PNG_READ_sCAL_SUPPORTED
 279       else if (chunk_name == png_sCAL)
 280          png_handle_sCAL(png_ptr, info_ptr, length);
 281 #endif
 282
 283 #ifdef PNG_READ_pHYs_SUPPORTED
 284       else if (chunk_name == png_pHYs)
 285          png_handle_pHYs(png_ptr, info_ptr, length);
 286 #endif
 287
 288 #ifdef PNG_READ_sBIT_SUPPORTED
 289       else if (chunk_name == png_sBIT)
 290          png_handle_sBIT(png_ptr, info_ptr, length);
 291 #endif
 292
 293 #ifdef PNG_READ_sRGB_SUPPORTED
 294       else if (chunk_name == png_sRGB)
 295          png_handle_sRGB(png_ptr, info_ptr, length);
 296 #endif
 297
 298 #ifdef PNG_READ_iCCP_SUPPORTED
 299       else if (chunk_name == png_iCCP)
 300          png_handle_iCCP(png_ptr, info_ptr, length);
 301 #endif
 302
 303 #ifdef PNG_READ_sPLT_SUPPORTED
 304       else if (chunk_name == png_sPLT)
 305          png_handle_sPLT(png_ptr, info_ptr, length);
 306 #endif
 307
 308 #ifdef PNG_READ_tEXt_SUPPORTED
 309       else if (chunk_name == png_tEXt)
 310          png_handle_tEXt(png_ptr, info_ptr, length);
 311 #endif
 312
 313 #ifdef PNG_READ_tIME_SUPPORTED
 314       else if (chunk_name == png_tIME)
 315          png_handle_tIME(png_ptr, info_ptr, length);
 316 #endif
 317
 318 #ifdef PNG_READ_tRNS_SUPPORTED
 319       else if (chunk_name == png_tRNS)
 320          png_handle_tRNS(png_ptr, info_ptr, length);
 321 #endif
 322
 323 #ifdef PNG_READ_zTXt_SUPPORTED
 324       else if (chunk_name == png_zTXt)
 325          png_handle_zTXt(png_ptr, info_ptr, length);
 326 #endif
 327
 328 #ifdef PNG_READ_iTXt_SUPPORTED
 329       else if (chunk_name == png_iTXt)
 330          png_handle_iTXt(png_ptr, info_ptr, length);
 331 #endif
 332
 333       else
 334          png_handle_unknown(png_ptr, info_ptr, length);
 335    }
 336 }
 337 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 338
 339 /* Optional call to update the users info_ptr structure */
 340 void PNGAPI
 341 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 342 {
 343    png_debug(1, "in png_read_update_info");
 344
 345    if (png_ptr == NULL)
 346       return;
 347
 348    png_read_start_row(png_ptr);
 349
 350 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
 351    png_read_transform_info(png_ptr, info_ptr);
 352 #else
 353    PNG_UNUSED(info_ptr)
 354 #endif
 355 }
 356
 357 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 358 /* Initialize palette, background, etc, after transformations
 359  * are set, but before any reading takes place.  This allows
 360  * the user to obtain a gamma-corrected palette, for example.
 361  * If the user doesn't call this, we will do it ourselves.
 362  */
 363 void PNGAPI
 364 png_start_read_image(png_structp png_ptr)
 365 {
 366    png_debug(1, "in png_start_read_image");
 367
 368    if (png_ptr != NULL)
 369      png_read_start_row(png_ptr);
 370 }
 371 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 372
 373 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 374 void PNGAPI
 375 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 376 {
 377    int ret;
 378
 379    png_row_info row_info;
 380
 381    if (png_ptr == NULL)
 382       return;
 383
 384    png_debug2(1, "in png_read_row (row %lu, pass %d)",
 385        (unsigned long)png_ptr->row_number, png_ptr->pass);
 386
 387    /* png_read_start_row sets the information (in particular iwidth) for this
 388     * interlace pass.
 389     */
 390    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 391       png_read_start_row(png_ptr);
 392
 393    /* 1.5.6: row_info moved out of png_struct to a local here. */
 394    row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
 395    row_info.color_type = png_ptr->color_type;
 396    row_info.bit_depth = png_ptr->bit_depth;
 397    row_info.channels = png_ptr->channels;
 398    row_info.pixel_depth = png_ptr->pixel_depth;
 399    row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
 400
 401    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
 402    {
 403    /* Check for transforms that have been set but were defined out */
 404 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
 405    if (png_ptr->transformations & PNG_INVERT_MONO)
 406       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
 407 #endif
 408
 409 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
 410    if (png_ptr->transformations & PNG_FILLER)
 411       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
 412 #endif
 413
 414 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
 415     !defined(PNG_READ_PACKSWAP_SUPPORTED)
 416    if (png_ptr->transformations & PNG_PACKSWAP)
 417       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
 418 #endif
 419
 420 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
 421    if (png_ptr->transformations & PNG_PACK)
 422       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
 423 #endif
 424
 425 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
 426    if (png_ptr->transformations & PNG_SHIFT)
 427       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
 428 #endif
 429
 430 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
 431    if (png_ptr->transformations & PNG_BGR)
 432       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
 433 #endif
 434
 435 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
 436    if (png_ptr->transformations & PNG_SWAP_BYTES)
 437       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
 438 #endif
 439    }
 440
 441 #ifdef PNG_READ_INTERLACING_SUPPORTED
 442    /* If interlaced and we do not need a new row, combine row and return.
 443     * Notice that the pixels we have from previous rows have been transformed
 444     * already; we can only combine like with like (transformed or
 445     * untransformed) and, because of the libpng API for interlaced images, this
 446     * means we must transform before de-interlacing.
 447     */
 448    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 449    {
 450       switch (png_ptr->pass)
 451       {
 452          case 0:
 453             if (png_ptr->row_number & 0x07)
 454             {
 455                if (dsp_row != NULL)
 456                   png_combine_row(png_ptr, dsp_row, 1/*display*/);
 457                png_read_finish_row(png_ptr);
 458                return;
 459             }
 460             break;
 461
 462          case 1:
 463             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
 464             {
 465                if (dsp_row != NULL)
 466                   png_combine_row(png_ptr, dsp_row, 1/*display*/);
 467
 468                png_read_finish_row(png_ptr);
 469                return;
 470             }
 471             break;
 472
 473          case 2:
 474             if ((png_ptr->row_number & 0x07) != 4)
 475             {
 476                if (dsp_row != NULL && (png_ptr->row_number & 4))
 477                   png_combine_row(png_ptr, dsp_row, 1/*display*/);
 478
 479                png_read_finish_row(png_ptr);
 480                return;
 481             }
 482             break;
 483
 484          case 3:
 485             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
 486             {
 487                if (dsp_row != NULL)
 488                   png_combine_row(png_ptr, dsp_row, 1/*display*/);
 489
 490                png_read_finish_row(png_ptr);
 491                return;
 492             }
 493             break;
 494
 495          case 4:
 496             if ((png_ptr->row_number & 3) != 2)
 497             {
 498                if (dsp_row != NULL && (png_ptr->row_number & 2))
 499                   png_combine_row(png_ptr, dsp_row, 1/*display*/);
 500
 501                png_read_finish_row(png_ptr);
 502                return;
 503             }
 504             break;
 505          case 5:
 506             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
 507             {
 508                if (dsp_row != NULL)
 509                   png_combine_row(png_ptr, dsp_row, 1/*display*/);
 510
 511                png_read_finish_row(png_ptr);
 512                return;
 513             }
 514             break;
 515
 516          default:
 517          case 6:
 518             if (!(png_ptr->row_number & 1))
 519             {
 520                png_read_finish_row(png_ptr);
 521                return;
 522             }
 523             break;
 524       }
 525    }
 526 #endif
 527
 528    if (!(png_ptr->mode & PNG_HAVE_IDAT))
 529       png_error(png_ptr, "Invalid attempt to read row data");
 530
 531    png_ptr->zstream.next_out = png_ptr->row_buf;
 532    png_ptr->zstream.avail_out =
 533        (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
 534        png_ptr->iwidth) + 1);
 535
 536    do
 537    {
 538       if (!(png_ptr->zstream.avail_in))
 539       {
 540          while (!png_ptr->idat_size)
 541          {
 542             png_crc_finish(png_ptr, 0);
 543
 544             png_ptr->idat_size = png_read_chunk_header(png_ptr);
 545             if (png_ptr->chunk_name != png_IDAT)
 546                png_error(png_ptr, "Not enough image data");
 547          }
 548          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
 549          png_ptr->zstream.next_in = png_ptr->zbuf;
 550          if (png_ptr->zbuf_size > png_ptr->idat_size)
 551             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
 552          png_crc_read(png_ptr, png_ptr->zbuf,
 553              (png_size_t)png_ptr->zstream.avail_in);
 554          png_ptr->idat_size -= png_ptr->zstream.avail_in;
 555       }
 556
 557       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 558
 559       if (ret == Z_STREAM_END)
 560       {
 561          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
 562             png_ptr->idat_size)
 563             png_benign_error(png_ptr, "Extra compressed data");
 564          png_ptr->mode |= PNG_AFTER_IDAT;
 565          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 566          break;
 567       }
 568
 569       if (ret != Z_OK)
 570          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
 571              "Decompression error");
 572
 573    } while (png_ptr->zstream.avail_out);
 574
 575    if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
 576    {
 577       if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
 578          png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
 579             png_ptr->prev_row + 1, png_ptr->row_buf[0]);
 580       else
 581          png_error(png_ptr, "bad adaptive filter value");
 582    }
 583
 584    /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
 585     * 1.5.6, while the buffer really is this big in current versions of libpng
 586     * it may not be in the future, so this was changed just to copy the
 587     * interlaced count:
 588     */
 589    png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
 590
 591 #ifdef PNG_MNG_FEATURES_SUPPORTED
 592    if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
 593        (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
 594    {
 595       /* Intrapixel differencing */
 596       png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
 597    }
 598 #endif
 599
 600
 601 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
 602    if (png_ptr->transformations)
 603       png_do_read_transformations(png_ptr, &row_info);
 604 #endif
 605
 606    /* The transformed pixel depth should match the depth now in row_info. */
 607    if (png_ptr->transformed_pixel_depth == 0)
 608    {
 609       png_ptr->transformed_pixel_depth = row_info.pixel_depth;
 610       if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
 611          png_error(png_ptr, "sequential row overflow");
 612    }
 613
 614    else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
 615       png_error(png_ptr, "internal sequential row size calculation error");
 616
 617 #ifdef PNG_READ_INTERLACING_SUPPORTED
 618    /* Blow up interlaced rows to full size */
 619    if (png_ptr->interlaced &&
 620       (png_ptr->transformations & PNG_INTERLACE))
 621    {
 622       if (png_ptr->pass < 6)
 623          png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
 624             png_ptr->transformations);
 625
 626       if (dsp_row != NULL)
 627          png_combine_row(png_ptr, dsp_row, 1/*display*/);
 628
 629       if (row != NULL)
 630          png_combine_row(png_ptr, row, 0/*row*/);
 631    }
 632
 633    else
 634 #endif
 635    {
 636       if (row != NULL)
 637          png_combine_row(png_ptr, row, -1/*ignored*/);
 638
 639       if (dsp_row != NULL)
 640          png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
 641    }
 642    png_read_finish_row(png_ptr);
 643
 644    if (png_ptr->read_row_fn != NULL)
 645       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
 646 }
 647 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 648
 649 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 650 /* Read one or more rows of image data.  If the image is interlaced,
 651  * and png_set_interlace_handling() has been called, the rows need to
 652  * contain the contents of the rows from the previous pass.  If the
 653  * image has alpha or transparency, and png_handle_alpha()[*] has been
 654  * called, the rows contents must be initialized to the contents of the
 655  * screen.
 656  *
 657  * "row" holds the actual image, and pixels are placed in it
 658  * as they arrive.  If the image is displayed after each pass, it will
 659  * appear to "sparkle" in.  "display_row" can be used to display a
 660  * "chunky" progressive image, with finer detail added as it becomes
 661  * available.  If you do not want this "chunky" display, you may pass
 662  * NULL for display_row.  If you do not want the sparkle display, and
 663  * you have not called png_handle_alpha(), you may pass NULL for rows.
 664  * If you have called png_handle_alpha(), and the image has either an
 665  * alpha channel or a transparency chunk, you must provide a buffer for
 666  * rows.  In this case, you do not have to provide a display_row buffer
 667  * also, but you may.  If the image is not interlaced, or if you have
 668  * not called png_set_interlace_handling(), the display_row buffer will
 669  * be ignored, so pass NULL to it.
 670  *
 671  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 672  */
 673
 674 void PNGAPI
 675 png_read_rows(png_structp png_ptr, png_bytepp row,
 676     png_bytepp display_row, png_uint_32 num_rows)
 677 {
 678    png_uint_32 i;
 679    png_bytepp rp;
 680    png_bytepp dp;
 681
 682    png_debug(1, "in png_read_rows");
 683
 684    if (png_ptr == NULL)
 685       return;
 686
 687    rp = row;
 688    dp = display_row;
 689    if (rp != NULL && dp != NULL)
 690       for (i = 0; i < num_rows; i++)
 691       {
 692          png_bytep rptr = *rp++;
 693          png_bytep dptr = *dp++;
 694
 695          png_read_row(png_ptr, rptr, dptr);
 696       }
 697
 698    else if (rp != NULL)
 699       for (i = 0; i < num_rows; i++)
 700       {
 701          png_bytep rptr = *rp;
 702          png_read_row(png_ptr, rptr, NULL);
 703          rp++;
 704       }
 705
 706    else if (dp != NULL)
 707       for (i = 0; i < num_rows; i++)
 708       {
 709          png_bytep dptr = *dp;
 710          png_read_row(png_ptr, NULL, dptr);
 711          dp++;
 712       }
 713 }
 714 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 715
 716 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 717 /* Read the entire image.  If the image has an alpha channel or a tRNS
 718  * chunk, and you have called png_handle_alpha()[*], you will need to
 719  * initialize the image to the current image that PNG will be overlaying.
 720  * We set the num_rows again here, in case it was incorrectly set in
 721  * png_read_start_row() by a call to png_read_update_info() or
 722  * png_start_read_image() if png_set_interlace_handling() wasn't called
 723  * prior to either of these functions like it should have been.  You can
 724  * only call this function once.  If you desire to have an image for
 725  * each pass of a interlaced image, use png_read_rows() instead.
 726  *
 727  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 728  */
 729 void PNGAPI
 730 png_read_image(png_structp png_ptr, png_bytepp image)
 731 {
 732    png_uint_32 i, image_height;
 733    int pass, j;
 734    png_bytepp rp;
 735
 736    png_debug(1, "in png_read_image");
 737
 738    if (png_ptr == NULL)
 739       return;
 740
 741 #ifdef PNG_READ_INTERLACING_SUPPORTED
 742    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 743    {
 744       pass = png_set_interlace_handling(png_ptr);
 745       /* And make sure transforms are initialized. */
 746       png_start_read_image(png_ptr);
 747    }
 748    else
 749    {
 750       if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
 751       {
 752          /* Caller called png_start_read_image or png_read_update_info without
 753           * first turning on the PNG_INTERLACE transform.  We can fix this here,
 754           * but the caller should do it!
 755           */
 756          png_warning(png_ptr, "Interlace handling should be turned on when "
 757             "using png_read_image");
 758          /* Make sure this is set correctly */
 759          png_ptr->num_rows = png_ptr->height;
 760       }
 761
 762       /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
 763        * the above error case.
 764        */
 765       pass = png_set_interlace_handling(png_ptr);
 766    }
 767 #else
 768    if (png_ptr->interlaced)
 769       png_error(png_ptr,
 770           "Cannot read interlaced image -- interlace handler disabled");
 771
 772    pass = 1;
 773 #endif
 774
 775    image_height=png_ptr->height;
 776
 777    for (j = 0; j < pass; j++)
 778    {
 779       rp = image;
 780       for (i = 0; i < image_height; i++)
 781       {
 782          png_read_row(png_ptr, *rp, NULL);
 783          rp++;
 784       }
 785    }
 786 }
 787 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 788
 789 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 790 /* Read the end of the PNG file.  Will not read past the end of the
 791  * file, will verify the end is accurate, and will read any comments
 792  * or time information at the end of the file, if info is not NULL.
 793  */
 794 void PNGAPI
 795 png_read_end(png_structp png_ptr, png_infop info_ptr)
 796 {
 797    png_debug(1, "in png_read_end");
 798
 799    if (png_ptr == NULL)
 800       return;
 801
 802    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 803
 804 #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
 805    /* Report invalid palette index; added at libng-1.5.10 */
 806    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 807       png_ptr->num_palette_max > png_ptr->num_palette)
 808      png_benign_error(png_ptr, "Read palette index exceeding num_palette");
 809 #endif
 810
 811    do
 812    {
 813       png_uint_32 length = png_read_chunk_header(png_ptr);
 814       png_uint_32 chunk_name = png_ptr->chunk_name;
 815
 816       if (chunk_name == png_IHDR)
 817          png_handle_IHDR(png_ptr, info_ptr, length);
 818
 819       else if (chunk_name == png_IEND)
 820          png_handle_IEND(png_ptr, info_ptr, length);
 821
 822 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 823       else if (png_chunk_unknown_handling(png_ptr, chunk_name) !=
 824          PNG_HANDLE_CHUNK_AS_DEFAULT)
 825       {
 826          if (chunk_name == png_IDAT)
 827          {
 828             if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 829                png_benign_error(png_ptr, "Too many IDATs found");
 830          }
 831          png_handle_unknown(png_ptr, info_ptr, length);
 832          if (chunk_name == png_PLTE)
 833             png_ptr->mode |= PNG_HAVE_PLTE;
 834       }
 835 #endif
 836
 837       else if (chunk_name == png_IDAT)
 838       {
 839          /* Zero length IDATs are legal after the last IDAT has been
 840           * read, but not after other chunks have been read.
 841           */
 842          if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 843             png_benign_error(png_ptr, "Too many IDATs found");
 844
 845          png_crc_finish(png_ptr, length);
 846       }
 847       else if (chunk_name == png_PLTE)
 848          png_handle_PLTE(png_ptr, info_ptr, length);
 849
 850 #ifdef PNG_READ_bKGD_SUPPORTED
 851       else if (chunk_name == png_bKGD)
 852          png_handle_bKGD(png_ptr, info_ptr, length);
 853 #endif
 854
 855 #ifdef PNG_READ_cHRM_SUPPORTED
 856       else if (chunk_name == png_cHRM)
 857          png_handle_cHRM(png_ptr, info_ptr, length);
 858 #endif
 859
 860 #ifdef PNG_READ_gAMA_SUPPORTED
 861       else if (chunk_name == png_gAMA)
 862          png_handle_gAMA(png_ptr, info_ptr, length);
 863 #endif
 864
 865 #ifdef PNG_READ_hIST_SUPPORTED
 866       else if (chunk_name == png_hIST)
 867          png_handle_hIST(png_ptr, info_ptr, length);
 868 #endif
 869
 870 #ifdef PNG_READ_oFFs_SUPPORTED
 871       else if (chunk_name == png_oFFs)
 872          png_handle_oFFs(png_ptr, info_ptr, length);
 873 #endif
 874
 875 #ifdef PNG_READ_pCAL_SUPPORTED
 876       else if (chunk_name == png_pCAL)
 877          png_handle_pCAL(png_ptr, info_ptr, length);
 878 #endif
 879
 880 #ifdef PNG_READ_sCAL_SUPPORTED
 881       else if (chunk_name == png_sCAL)
 882          png_handle_sCAL(png_ptr, info_ptr, length);
 883 #endif
 884
 885 #ifdef PNG_READ_pHYs_SUPPORTED
 886       else if (chunk_name == png_pHYs)
 887          png_handle_pHYs(png_ptr, info_ptr, length);
 888 #endif
 889
 890 #ifdef PNG_READ_sBIT_SUPPORTED
 891       else if (chunk_name == png_sBIT)
 892          png_handle_sBIT(png_ptr, info_ptr, length);
 893 #endif
 894
 895 #ifdef PNG_READ_sRGB_SUPPORTED
 896       else if (chunk_name == png_sRGB)
 897          png_handle_sRGB(png_ptr, info_ptr, length);
 898 #endif
 899
 900 #ifdef PNG_READ_iCCP_SUPPORTED
 901       else if (chunk_name == png_iCCP)
 902          png_handle_iCCP(png_ptr, info_ptr, length);
 903 #endif
 904
 905 #ifdef PNG_READ_sPLT_SUPPORTED
 906       else if (chunk_name == png_sPLT)
 907          png_handle_sPLT(png_ptr, info_ptr, length);
 908 #endif
 909
 910 #ifdef PNG_READ_tEXt_SUPPORTED
 911       else if (chunk_name == png_tEXt)
 912          png_handle_tEXt(png_ptr, info_ptr, length);
 913 #endif
 914
 915 #ifdef PNG_READ_tIME_SUPPORTED
 916       else if (chunk_name == png_tIME)
 917          png_handle_tIME(png_ptr, info_ptr, length);
 918 #endif
 919
 920 #ifdef PNG_READ_tRNS_SUPPORTED
 921       else if (chunk_name == png_tRNS)
 922          png_handle_tRNS(png_ptr, info_ptr, length);
 923 #endif
 924
 925 #ifdef PNG_READ_zTXt_SUPPORTED
 926       else if (chunk_name == png_zTXt)
 927          png_handle_zTXt(png_ptr, info_ptr, length);
 928 #endif
 929
 930 #ifdef PNG_READ_iTXt_SUPPORTED
 931       else if (chunk_name == png_iTXt)
 932          png_handle_iTXt(png_ptr, info_ptr, length);
 933 #endif
 934
 935       else
 936          png_handle_unknown(png_ptr, info_ptr, length);
 937    } while (!(png_ptr->mode & PNG_HAVE_IEND));
 938 }
 939 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
 940
 941 /* Free all memory used by the read */
 942 void PNGAPI
 943 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
 944     png_infopp end_info_ptr_ptr)
 945 {
 946    png_structp png_ptr = NULL;
 947    png_infop info_ptr = NULL, end_info_ptr = NULL;
 948 #ifdef PNG_USER_MEM_SUPPORTED
 949    png_free_ptr free_fn = NULL;
 950    png_voidp mem_ptr = NULL;
 951 #endif
 952
 953    png_debug(1, "in png_destroy_read_struct");
 954
 955    if (png_ptr_ptr != NULL)
 956       png_ptr = *png_ptr_ptr;
 957    if (png_ptr == NULL)
 958       return;
 959
 960 #ifdef PNG_USER_MEM_SUPPORTED
 961    free_fn = png_ptr->free_fn;
 962    mem_ptr = png_ptr->mem_ptr;
 963 #endif
 964
 965    if (info_ptr_ptr != NULL)
 966       info_ptr = *info_ptr_ptr;
 967
 968    if (end_info_ptr_ptr != NULL)
 969       end_info_ptr = *end_info_ptr_ptr;
 970
 971    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
 972
 973    if (info_ptr != NULL)
 974    {
 975 #ifdef PNG_TEXT_SUPPORTED
 976       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
 977 #endif
 978
 979 #ifdef PNG_USER_MEM_SUPPORTED
 980       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
 981           (png_voidp)mem_ptr);
 982 #else
 983       png_destroy_struct((png_voidp)info_ptr);
 984 #endif
 985       *info_ptr_ptr = NULL;
 986    }
 987
 988    if (end_info_ptr != NULL)
 989    {
 990 #ifdef PNG_READ_TEXT_SUPPORTED
 991       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
 992 #endif
 993 #ifdef PNG_USER_MEM_SUPPORTED
 994       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
 995           (png_voidp)mem_ptr);
 996 #else
 997       png_destroy_struct((png_voidp)end_info_ptr);
 998 #endif
 999       *end_info_ptr_ptr = NULL;
1000    }
1001
1002    if (png_ptr != NULL)
1003    {
1004 #ifdef PNG_USER_MEM_SUPPORTED
1005       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1006           (png_voidp)mem_ptr);
1007 #else
1008       png_destroy_struct((png_voidp)png_ptr);
1009 #endif
1010       *png_ptr_ptr = NULL;
1011    }
1012 }
1013
1014 /* Free all memory used by the read (old method) */
1015 void /* PRIVATE */
1016 png_read_destroy(png_structp png_ptr, png_infop info_ptr,
1017     png_infop end_info_ptr)
1018 {
1019 #ifdef PNG_SETJMP_SUPPORTED
1020    jmp_buf tmp_jmp;
1021 #endif
1022    png_error_ptr error_fn;
1023 #ifdef PNG_WARNINGS_SUPPORTED
1024    png_error_ptr warning_fn;
1025 #endif
1026    png_voidp error_ptr;
1027 #ifdef PNG_USER_MEM_SUPPORTED
1028    png_free_ptr free_fn;
1029 #endif
1030
1031    png_debug(1, "in png_read_destroy");
1032
1033    if (info_ptr != NULL)
1034       png_info_destroy(png_ptr, info_ptr);
1035
1036    if (end_info_ptr != NULL)
1037       png_info_destroy(png_ptr, end_info_ptr);
1038
1039 #ifdef PNG_READ_GAMMA_SUPPORTED
1040    png_destroy_gamma_table(png_ptr);
1041 #endif
1042
1043    png_free(png_ptr, png_ptr->zbuf);
1044    png_free(png_ptr, png_ptr->big_row_buf);
1045    png_free(png_ptr, png_ptr->big_prev_row);
1046    png_free(png_ptr, png_ptr->chunkdata);
1047
1048 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1049    png_free(png_ptr, png_ptr->palette_lookup);
1050    png_free(png_ptr, png_ptr->quantize_index);
1051 #endif
1052
1053    if (png_ptr->free_me & PNG_FREE_PLTE)
1054       png_zfree(png_ptr, png_ptr->palette);
1055    png_ptr->free_me &= ~PNG_FREE_PLTE;
1056
1057 #if defined(PNG_tRNS_SUPPORTED) || \
1058     defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1059    if (png_ptr->free_me & PNG_FREE_TRNS)
1060       png_free(png_ptr, png_ptr->trans_alpha);
1061    png_ptr->free_me &= ~PNG_FREE_TRNS;
1062 #endif
1063
1064 #ifdef PNG_READ_hIST_SUPPORTED
1065    if (png_ptr->free_me & PNG_FREE_HIST)
1066       png_free(png_ptr, png_ptr->hist);
1067    png_ptr->free_me &= ~PNG_FREE_HIST;
1068 #endif
1069
1070    inflateEnd(&png_ptr->zstream);
1071
1072 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1073    png_free(png_ptr, png_ptr->save_buffer);
1074 #endif
1075
1076    /* Save the important info out of the png_struct, in case it is
1077     * being used again.
1078     */
1079 #ifdef PNG_SETJMP_SUPPORTED
1080    png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
1081 #endif
1082
1083    error_fn = png_ptr->error_fn;
1084 #ifdef PNG_WARNINGS_SUPPORTED
1085    warning_fn = png_ptr->warning_fn;
1086 #endif
1087    error_ptr = png_ptr->error_ptr;
1088 #ifdef PNG_USER_MEM_SUPPORTED
1089    free_fn = png_ptr->free_fn;
1090 #endif
1091
1092    png_memset(png_ptr, 0, png_sizeof(png_struct));
1093
1094    png_ptr->error_fn = error_fn;
1095 #ifdef PNG_WARNINGS_SUPPORTED
1096    png_ptr->warning_fn = warning_fn;
1097 #endif
1098    png_ptr->error_ptr = error_ptr;
1099 #ifdef PNG_USER_MEM_SUPPORTED
1100    png_ptr->free_fn = free_fn;
1101 #endif
1102
1103 #ifdef PNG_SETJMP_SUPPORTED
1104    png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
1105 #endif
1106
1107 }
1108
1109 void PNGAPI
1110 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1111 {
1112    if (png_ptr == NULL)
1113       return;
1114
1115    png_ptr->read_row_fn = read_row_fn;
1116 }
1117
1118
1119 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1120 #ifdef PNG_INFO_IMAGE_SUPPORTED
1121 void PNGAPI
1122 png_read_png(png_structp png_ptr, png_infop info_ptr,
1123                            int transforms,
1124                            voidp params)
1125 {
1126    int row;
1127
1128    if (png_ptr == NULL || info_ptr == NULL)
1129       return;
1130
1131    /* png_read_info() gives us all of the information from the
1132     * PNG file before the first IDAT (image data chunk).
1133     */
1134    png_read_info(png_ptr, info_ptr);
1135    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1136       png_error(png_ptr, "Image is too high to process with png_read_png()");
1137
1138    /* -------------- image transformations start here ------------------- */
1139
1140 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1141    /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
1142     */
1143    if (transforms & PNG_TRANSFORM_SCALE_16)
1144    {
1145      /* Added at libpng-1.5.4. "strip_16" produces the same result that it
1146       * did in earlier versions, while "scale_16" is now more accurate.
1147       */
1148       png_set_scale_16(png_ptr);
1149    }
1150 #endif
1151
1152 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1153    /* If both SCALE and STRIP are required pngrtran will effectively cancel the
1154     * latter by doing SCALE first.  This is ok and allows apps not to check for
1155     * which is supported to get the right answer.
1156     */
1157    if (transforms & PNG_TRANSFORM_STRIP_16)
1158       png_set_strip_16(png_ptr);
1159 #endif
1160
1161 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1162    /* Strip alpha bytes from the input data without combining with
1163     * the background (not recommended).
1164     */
1165    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1166       png_set_strip_alpha(png_ptr);
1167 #endif
1168
1169 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1170    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1171     * byte into separate bytes (useful for paletted and grayscale images).
1172     */
1173    if (transforms & PNG_TRANSFORM_PACKING)
1174       png_set_packing(png_ptr);
1175 #endif
1176
1177 #ifdef PNG_READ_PACKSWAP_SUPPORTED
1178    /* Change the order of packed pixels to least significant bit first
1179     * (not useful if you are using png_set_packing).
1180     */
1181    if (transforms & PNG_TRANSFORM_PACKSWAP)
1182       png_set_packswap(png_ptr);
1183 #endif
1184
1185 #ifdef PNG_READ_EXPAND_SUPPORTED
1186    /* Expand paletted colors into true RGB triplets
1187     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1188     * Expand paletted or RGB images with transparency to full alpha
1189     * channels so the data will be available as RGBA quartets.
1190     */
1191    if (transforms & PNG_TRANSFORM_EXPAND)
1192       if ((png_ptr->bit_depth < 8) ||
1193           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1194           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1195          png_set_expand(png_ptr);
1196 #endif
1197
1198    /* We don't handle background color or gamma transformation or quantizing.
1199     */
1200
1201 #ifdef PNG_READ_INVERT_SUPPORTED
1202    /* Invert monochrome files to have 0 as white and 1 as black
1203     */
1204    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1205       png_set_invert_mono(png_ptr);
1206 #endif
1207
1208 #ifdef PNG_READ_SHIFT_SUPPORTED
1209    /* If you want to shift the pixel values from the range [0,255] or
1210     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1211     * colors were originally in:
1212     */
1213    if ((transforms & PNG_TRANSFORM_SHIFT)
1214        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1215    {
1216       png_color_8p sig_bit;
1217
1218       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1219       png_set_shift(png_ptr, sig_bit);
1220    }
1221 #endif
1222
1223 #ifdef PNG_READ_BGR_SUPPORTED
1224    /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
1225    if (transforms & PNG_TRANSFORM_BGR)
1226       png_set_bgr(png_ptr);
1227 #endif
1228
1229 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1230    /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
1231    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1232       png_set_swap_alpha(png_ptr);
1233 #endif
1234
1235 #ifdef PNG_READ_SWAP_SUPPORTED
1236    /* Swap bytes of 16-bit files to least significant byte first */
1237    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1238       png_set_swap(png_ptr);
1239 #endif
1240
1241 /* Added at libpng-1.2.41 */
1242 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1243    /* Invert the alpha channel from opacity to transparency */
1244    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1245       png_set_invert_alpha(png_ptr);
1246 #endif
1247
1248 /* Added at libpng-1.2.41 */
1249 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1250    /* Expand grayscale image to RGB */
1251    if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
1252       png_set_gray_to_rgb(png_ptr);
1253 #endif
1254
1255 /* Added at libpng-1.5.4 */
1256 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1257    if (transforms & PNG_TRANSFORM_EXPAND_16)
1258       png_set_expand_16(png_ptr);
1259 #endif
1260
1261    /* We don't handle adding filler bytes */
1262
1263    /* We use png_read_image and rely on that for interlace handling, but we also
1264     * call png_read_update_info therefore must turn on interlace handling now:
1265     */
1266    (void)png_set_interlace_handling(png_ptr);
1267
1268    /* Optional call to gamma correct and add the background to the palette
1269     * and update info structure.  REQUIRED if you are expecting libpng to
1270     * update the palette for you (i.e., you selected such a transform above).
1271     */
1272    png_read_update_info(png_ptr, info_ptr);
1273
1274    /* -------------- image transformations end here ------------------- */
1275
1276    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1277    if (info_ptr->row_pointers == NULL)
1278    {
1279       png_uint_32 iptr;
1280
1281       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1282           info_ptr->height * png_sizeof(png_bytep));
1283       for (iptr=0; iptr<info_ptr->height; iptr++)
1284          info_ptr->row_pointers[iptr] = NULL;
1285
1286       info_ptr->free_me |= PNG_FREE_ROWS;
1287
1288       for (row = 0; row < (int)info_ptr->height; row++)
1289          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1290             png_get_rowbytes(png_ptr, info_ptr));
1291    }
1292
1293    png_read_image(png_ptr, info_ptr->row_pointers);
1294    info_ptr->valid |= PNG_INFO_IDAT;
1295
1296    /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
1297    png_read_end(png_ptr, info_ptr);
1298
1299    PNG_UNUSED(transforms)   /* Quiet compiler warnings */
1300    PNG_UNUSED(params)
1301
1302 }
1303 #endif /* PNG_INFO_IMAGE_SUPPORTED */
1304 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
1305 #endif /* PNG_READ_SUPPORTED */