com32/lib/libpng/pngread.c

   1
   2 /* pngread.c - read a PNG file
   3  *
   4  * libpng 1.2.8 - December 3, 2004
   5  * For conditions of distribution and use, see copyright notice in png.h
   6  * Copyright (c) 1998-2004 Glenn Randers-Pehrson
   7  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   8  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   9  *
  10  * This file contains routines that an application calls directly to
  11  * read a PNG file or stream.
  12  */
  13
  14 #define PNG_INTERNAL
  15 #include "png.h"
  16
  17 /* Create a PNG structure for reading, and allocate any memory needed. */
  18 png_structp PNGAPI
  19 png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
  20    png_error_ptr error_fn, png_error_ptr warn_fn)
  21 {
  22
  23 #ifdef PNG_USER_MEM_SUPPORTED
  24    return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
  25       warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
  26 }
  27
  28 /* Alternate create PNG structure for reading, and allocate any memory needed. */
  29 png_structp PNGAPI
  30 png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
  31    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
  32    png_malloc_ptr malloc_fn, png_free_ptr free_fn)
  33 {
  34 #endif /* PNG_USER_MEM_SUPPORTED */
  35
  36    png_structp png_ptr;
  37
  38 #ifdef PNG_SETJMP_SUPPORTED
  39 #ifdef USE_FAR_KEYWORD
  40    jmp_buf jmpbuf;
  41 #endif
  42 #endif
  43
  44    int i;
  45
  46    png_debug(1, "in png_create_read_struct\n");
  47 #ifdef PNG_USER_MEM_SUPPORTED
  48    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
  49       (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
  50 #else
  51    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
  52 #endif
  53    if (png_ptr == NULL)
  54       return (NULL);
  55
  56 #if !defined(PNG_1_0_X)
  57 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
  58    png_init_mmx_flags(png_ptr);   /* 1.2.0 addition */
  59 #endif
  60 #endif /* PNG_1_0_X */
  61
  62    /* added at libpng-1.2.6 */
  63 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
  64    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
  65    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
  66 #endif
  67
  68 #ifdef PNG_SETJMP_SUPPORTED
  69 #ifdef USE_FAR_KEYWORD
  70    if (setjmp(jmpbuf))
  71 #else
  72    if (setjmp(png_ptr->jmpbuf))
  73 #endif
  74    {
  75       png_free(png_ptr, png_ptr->zbuf);
  76       png_ptr->zbuf=NULL;
  77 #ifdef PNG_USER_MEM_SUPPORTED
  78       png_destroy_struct_2((png_voidp)png_ptr,
  79          (png_free_ptr)free_fn, (png_voidp)mem_ptr);
  80 #else
  81       png_destroy_struct((png_voidp)png_ptr);
  82 #endif
  83       return (NULL);
  84    }
  85 #ifdef USE_FAR_KEYWORD
  86    png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
  87 #endif
  88 #endif
  89
  90 #ifdef PNG_USER_MEM_SUPPORTED
  91    png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
  92 #endif
  93
  94    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
  95
  96    i=0;
  97    do
  98    {
  99      if(user_png_ver[i] != png_libpng_ver[i])
 100         png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 101    } while (png_libpng_ver[i++]);
 102
 103    if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
 104    {
 105      /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
 106       * we must recompile any applications that use any older library version.
 107       * For versions after libpng 1.0, we will be compatible, so we need
 108       * only check the first digit.
 109       */
 110      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
 111          (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
 112          (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
 113      {
 114 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
 115         char msg[80];
 116         if (user_png_ver)
 117         {
 118           sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
 119              user_png_ver);
 120           png_warning(png_ptr, msg);
 121         }
 122         sprintf(msg, "Application  is  running with png.c from libpng-%.20s",
 123            png_libpng_ver);
 124         png_warning(png_ptr, msg);
 125 #endif
 126 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 127         png_ptr->flags=0;
 128 #endif
 129         png_error(png_ptr,
 130            "Incompatible libpng version in application and library");
 131      }
 132    }
 133
 134    /* initialize zbuf - compression buffer */
 135    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 136    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
 137      (png_uint_32)png_ptr->zbuf_size);
 138    png_ptr->zstream.zalloc = png_zalloc;
 139    png_ptr->zstream.zfree = png_zfree;
 140    png_ptr->zstream.opaque = (voidpf)png_ptr;
 141
 142    switch (inflateInit(&png_ptr->zstream))
 143    {
 144      case Z_OK: /* Do nothing */ break;
 145      case Z_MEM_ERROR:
 146      case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
 147      case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
 148      default: png_error(png_ptr, "Unknown zlib error");
 149    }
 150
 151    png_ptr->zstream.next_out = png_ptr->zbuf;
 152    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 153
 154    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
 155
 156 #ifdef PNG_SETJMP_SUPPORTED
 157 /* Applications that neglect to set up their own setjmp() and then encounter
 158    a png_error() will longjmp here.  Since the jmpbuf is then meaningless we
 159    abort instead of returning. */
 160 #ifdef USE_FAR_KEYWORD
 161    if (setjmp(jmpbuf))
 162       PNG_ABORT();
 163    png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
 164 #else
 165    if (setjmp(png_ptr->jmpbuf))
 166       PNG_ABORT();
 167 #endif
 168 #endif
 169    return (png_ptr);
 170 }
 171
 172 /* Initialize PNG structure for reading, and allocate any memory needed.
 173    This interface is deprecated in favour of the png_create_read_struct(),
 174    and it will eventually disappear. */
 175 #if defined(PNG_1_0_X) || defined (PNG_1_2_X)
 176 #undef png_read_init
 177 void PNGAPI
 178 png_read_init(png_structp png_ptr)
 179 {
 180    /* We only come here via pre-1.0.7-compiled applications */
 181    png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
 182 }
 183 #endif
 184
 185 void PNGAPI
 186 png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
 187    png_size_t png_struct_size, png_size_t png_info_size)
 188 {
 189    /* We only come here via pre-1.0.12-compiled applications */
 190 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
 191    if(png_sizeof(png_struct) > png_struct_size ||
 192       png_sizeof(png_info) > png_info_size)
 193    {
 194       char msg[80];
 195       png_ptr->warning_fn=NULL;
 196       if (user_png_ver)
 197       {
 198         sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
 199            user_png_ver);
 200         png_warning(png_ptr, msg);
 201       }
 202       sprintf(msg, "Application  is  running with png.c from libpng-%.20s",
 203          png_libpng_ver);
 204       png_warning(png_ptr, msg);
 205    }
 206 #endif
 207    if(png_sizeof(png_struct) > png_struct_size)
 208      {
 209        png_ptr->error_fn=NULL;
 210 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 211        png_ptr->flags=0;
 212 #endif
 213        png_error(png_ptr,
 214        "The png struct allocated by the application for reading is too small.");
 215      }
 216    if(png_sizeof(png_info) > png_info_size)
 217      {
 218        png_ptr->error_fn=NULL;
 219 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 220        png_ptr->flags=0;
 221 #endif
 222        png_error(png_ptr,
 223          "The info struct allocated by application for reading is too small.");
 224      }
 225    png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
 226 }
 227
 228 void PNGAPI
 229 png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
 230    png_size_t png_struct_size)
 231 {
 232 #ifdef PNG_SETJMP_SUPPORTED
 233    jmp_buf tmp_jmp;  /* to save current jump buffer */
 234 #endif
 235
 236    int i=0;
 237
 238    png_structp png_ptr=*ptr_ptr;
 239
 240    do
 241    {
 242      if(user_png_ver[i] != png_libpng_ver[i])
 243      {
 244 #ifdef PNG_LEGACY_SUPPORTED
 245        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 246 #else
 247        png_ptr->warning_fn=NULL;
 248        png_warning(png_ptr,
 249         "Application uses deprecated png_read_init() and should be recompiled.");
 250        break;
 251 #endif
 252      }
 253    } while (png_libpng_ver[i++]);
 254
 255    png_debug(1, "in png_read_init_3\n");
 256
 257 #ifdef PNG_SETJMP_SUPPORTED
 258    /* save jump buffer and error functions */
 259    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
 260 #endif
 261
 262    if(png_sizeof(png_struct) > png_struct_size)
 263      {
 264        png_destroy_struct(png_ptr);
 265        *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
 266        png_ptr = *ptr_ptr;
 267      }
 268
 269    /* reset all variables to 0 */
 270    png_memset(png_ptr, 0, png_sizeof (png_struct));
 271
 272 #ifdef PNG_SETJMP_SUPPORTED
 273    /* restore jump buffer */
 274    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
 275 #endif
 276
 277    /* added at libpng-1.2.6 */
 278 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
 279    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
 280    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 281 #endif
 282
 283    /* initialize zbuf - compression buffer */
 284    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 285    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
 286      (png_uint_32)png_ptr->zbuf_size);
 287    png_ptr->zstream.zalloc = png_zalloc;
 288    png_ptr->zstream.zfree = png_zfree;
 289    png_ptr->zstream.opaque = (voidpf)png_ptr;
 290
 291    switch (inflateInit(&png_ptr->zstream))
 292    {
 293      case Z_OK: /* Do nothing */ break;
 294      case Z_MEM_ERROR:
 295      case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
 296      case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
 297      default: png_error(png_ptr, "Unknown zlib error");
 298    }
 299
 300    png_ptr->zstream.next_out = png_ptr->zbuf;
 301    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 302
 303    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
 304 }
 305
 306 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 307 /* Read the information before the actual image data.  This has been
 308  * changed in v0.90 to allow reading a file that already has the magic
 309  * bytes read from the stream.  You can tell libpng how many bytes have
 310  * been read from the beginning of the stream (up to the maximum of 8)
 311  * via png_set_sig_bytes(), and we will only check the remaining bytes
 312  * here.  The application can then have access to the signature bytes we
 313  * read if it is determined that this isn't a valid PNG file.
 314  */
 315 void PNGAPI
 316 png_read_info(png_structp png_ptr, png_infop info_ptr)
 317 {
 318    png_debug(1, "in png_read_info\n");
 319    /* If we haven't checked all of the PNG signature bytes, do so now. */
 320    if (png_ptr->sig_bytes < 8)
 321    {
 322       png_size_t num_checked = png_ptr->sig_bytes,
 323                  num_to_check = 8 - num_checked;
 324
 325       png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
 326       png_ptr->sig_bytes = 8;
 327
 328       if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
 329       {
 330          if (num_checked < 4 &&
 331              png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
 332             png_error(png_ptr, "Not a PNG file");
 333          else
 334             png_error(png_ptr, "PNG file corrupted by ASCII conversion");
 335       }
 336       if (num_checked < 3)
 337          png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
 338    }
 339
 340    for(;;)
 341    {
 342 #ifdef PNG_USE_LOCAL_ARRAYS
 343       PNG_IHDR;
 344       PNG_IDAT;
 345       PNG_IEND;
 346       PNG_PLTE;
 347 #if defined(PNG_READ_bKGD_SUPPORTED)
 348       PNG_bKGD;
 349 #endif
 350 #if defined(PNG_READ_cHRM_SUPPORTED)
 351       PNG_cHRM;
 352 #endif
 353 #if defined(PNG_READ_gAMA_SUPPORTED)
 354       PNG_gAMA;
 355 #endif
 356 #if defined(PNG_READ_hIST_SUPPORTED)
 357       PNG_hIST;
 358 #endif
 359 #if defined(PNG_READ_iCCP_SUPPORTED)
 360       PNG_iCCP;
 361 #endif
 362 #if defined(PNG_READ_iTXt_SUPPORTED)
 363       PNG_iTXt;
 364 #endif
 365 #if defined(PNG_READ_oFFs_SUPPORTED)
 366       PNG_oFFs;
 367 #endif
 368 #if defined(PNG_READ_pCAL_SUPPORTED)
 369       PNG_pCAL;
 370 #endif
 371 #if defined(PNG_READ_pHYs_SUPPORTED)
 372       PNG_pHYs;
 373 #endif
 374 #if defined(PNG_READ_sBIT_SUPPORTED)
 375       PNG_sBIT;
 376 #endif
 377 #if defined(PNG_READ_sCAL_SUPPORTED)
 378       PNG_sCAL;
 379 #endif
 380 #if defined(PNG_READ_sPLT_SUPPORTED)
 381       PNG_sPLT;
 382 #endif
 383 #if defined(PNG_READ_sRGB_SUPPORTED)
 384       PNG_sRGB;
 385 #endif
 386 #if defined(PNG_READ_tEXt_SUPPORTED)
 387       PNG_tEXt;
 388 #endif
 389 #if defined(PNG_READ_tIME_SUPPORTED)
 390       PNG_tIME;
 391 #endif
 392 #if defined(PNG_READ_tRNS_SUPPORTED)
 393       PNG_tRNS;
 394 #endif
 395 #if defined(PNG_READ_zTXt_SUPPORTED)
 396       PNG_zTXt;
 397 #endif
 398 #endif /* PNG_USE_LOCAL_ARRAYS */
 399       png_byte chunk_length[4];
 400       png_uint_32 length;
 401
 402       png_read_data(png_ptr, chunk_length, 4);
 403       length = png_get_uint_31(png_ptr,chunk_length);
 404
 405       png_reset_crc(png_ptr);
 406       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 407
 408       png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
 409          length);
 410
 411       /* This should be a binary subdivision search or a hash for
 412        * matching the chunk name rather than a linear search.
 413        */
 414       if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
 415          png_handle_IHDR(png_ptr, info_ptr, length);
 416       else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
 417          png_handle_IEND(png_ptr, info_ptr, length);
 418 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 419       else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
 420       {
 421          if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 422             png_ptr->mode |= PNG_HAVE_IDAT;
 423          png_handle_unknown(png_ptr, info_ptr, length);
 424          if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 425             png_ptr->mode |= PNG_HAVE_PLTE;
 426          else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 427          {
 428             if (!(png_ptr->mode & PNG_HAVE_IHDR))
 429                png_error(png_ptr, "Missing IHDR before IDAT");
 430             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 431                      !(png_ptr->mode & PNG_HAVE_PLTE))
 432                png_error(png_ptr, "Missing PLTE before IDAT");
 433             break;
 434          }
 435       }
 436 #endif
 437       else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 438          png_handle_PLTE(png_ptr, info_ptr, length);
 439       else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 440       {
 441          if (!(png_ptr->mode & PNG_HAVE_IHDR))
 442             png_error(png_ptr, "Missing IHDR before IDAT");
 443          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 444                   !(png_ptr->mode & PNG_HAVE_PLTE))
 445             png_error(png_ptr, "Missing PLTE before IDAT");
 446
 447          png_ptr->idat_size = length;
 448          png_ptr->mode |= PNG_HAVE_IDAT;
 449          break;
 450       }
 451 #if defined(PNG_READ_bKGD_SUPPORTED)
 452       else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
 453          png_handle_bKGD(png_ptr, info_ptr, length);
 454 #endif
 455 #if defined(PNG_READ_cHRM_SUPPORTED)
 456       else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
 457          png_handle_cHRM(png_ptr, info_ptr, length);
 458 #endif
 459 #if defined(PNG_READ_gAMA_SUPPORTED)
 460       else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
 461          png_handle_gAMA(png_ptr, info_ptr, length);
 462 #endif
 463 #if defined(PNG_READ_hIST_SUPPORTED)
 464       else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
 465          png_handle_hIST(png_ptr, info_ptr, length);
 466 #endif
 467 #if defined(PNG_READ_oFFs_SUPPORTED)
 468       else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
 469          png_handle_oFFs(png_ptr, info_ptr, length);
 470 #endif
 471 #if defined(PNG_READ_pCAL_SUPPORTED)
 472       else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
 473          png_handle_pCAL(png_ptr, info_ptr, length);
 474 #endif
 475 #if defined(PNG_READ_sCAL_SUPPORTED)
 476       else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
 477          png_handle_sCAL(png_ptr, info_ptr, length);
 478 #endif
 479 #if defined(PNG_READ_pHYs_SUPPORTED)
 480       else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
 481          png_handle_pHYs(png_ptr, info_ptr, length);
 482 #endif
 483 #if defined(PNG_READ_sBIT_SUPPORTED)
 484       else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
 485          png_handle_sBIT(png_ptr, info_ptr, length);
 486 #endif
 487 #if defined(PNG_READ_sRGB_SUPPORTED)
 488       else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
 489          png_handle_sRGB(png_ptr, info_ptr, length);
 490 #endif
 491 #if defined(PNG_READ_iCCP_SUPPORTED)
 492       else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
 493          png_handle_iCCP(png_ptr, info_ptr, length);
 494 #endif
 495 #if defined(PNG_READ_sPLT_SUPPORTED)
 496       else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
 497          png_handle_sPLT(png_ptr, info_ptr, length);
 498 #endif
 499 #if defined(PNG_READ_tEXt_SUPPORTED)
 500       else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
 501          png_handle_tEXt(png_ptr, info_ptr, length);
 502 #endif
 503 #if defined(PNG_READ_tIME_SUPPORTED)
 504       else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
 505          png_handle_tIME(png_ptr, info_ptr, length);
 506 #endif
 507 #if defined(PNG_READ_tRNS_SUPPORTED)
 508       else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
 509          png_handle_tRNS(png_ptr, info_ptr, length);
 510 #endif
 511 #if defined(PNG_READ_zTXt_SUPPORTED)
 512       else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
 513          png_handle_zTXt(png_ptr, info_ptr, length);
 514 #endif
 515 #if defined(PNG_READ_iTXt_SUPPORTED)
 516       else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
 517          png_handle_iTXt(png_ptr, info_ptr, length);
 518 #endif
 519       else
 520          png_handle_unknown(png_ptr, info_ptr, length);
 521    }
 522 }
 523 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 524
 525 /* optional call to update the users info_ptr structure */
 526 void PNGAPI
 527 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 528 {
 529    png_debug(1, "in png_read_update_info\n");
 530    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 531       png_read_start_row(png_ptr);
 532    else
 533       png_warning(png_ptr,
 534       "Ignoring extra png_read_update_info() call; row buffer not reallocated");
 535    png_read_transform_info(png_ptr, info_ptr);
 536 }
 537
 538 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 539 /* Initialize palette, background, etc, after transformations
 540  * are set, but before any reading takes place.  This allows
 541  * the user to obtain a gamma-corrected palette, for example.
 542  * If the user doesn't call this, we will do it ourselves.
 543  */
 544 void PNGAPI
 545 png_start_read_image(png_structp png_ptr)
 546 {
 547    png_debug(1, "in png_start_read_image\n");
 548    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 549       png_read_start_row(png_ptr);
 550 }
 551 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 552
 553 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 554 void PNGAPI
 555 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 556 {
 557 #ifdef PNG_USE_LOCAL_ARRAYS
 558    PNG_IDAT;
 559    const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
 560    const int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 561 #endif
 562    int ret;
 563    png_debug2(1, "in png_read_row (row %lu, pass %d)\n",
 564       png_ptr->row_number, png_ptr->pass);
 565    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 566       png_read_start_row(png_ptr);
 567    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
 568    {
 569    /* check for transforms that have been set but were defined out */
 570 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
 571    if (png_ptr->transformations & PNG_INVERT_MONO)
 572       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
 573 #endif
 574 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
 575    if (png_ptr->transformations & PNG_FILLER)
 576       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
 577 #endif
 578 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
 579    if (png_ptr->transformations & PNG_PACKSWAP)
 580       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
 581 #endif
 582 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
 583    if (png_ptr->transformations & PNG_PACK)
 584       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
 585 #endif
 586 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
 587    if (png_ptr->transformations & PNG_SHIFT)
 588       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
 589 #endif
 590 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
 591    if (png_ptr->transformations & PNG_BGR)
 592       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
 593 #endif
 594 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
 595    if (png_ptr->transformations & PNG_SWAP_BYTES)
 596       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
 597 #endif
 598    }
 599
 600 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 601    /* if interlaced and we do not need a new row, combine row and return */
 602    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 603    {
 604       switch (png_ptr->pass)
 605       {
 606          case 0:
 607             if (png_ptr->row_number & 0x07)
 608             {
 609                if (dsp_row != NULL)
 610                   png_combine_row(png_ptr, dsp_row,
 611                      png_pass_dsp_mask[png_ptr->pass]);
 612                png_read_finish_row(png_ptr);
 613                return;
 614             }
 615             break;
 616          case 1:
 617             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
 618             {
 619                if (dsp_row != NULL)
 620                   png_combine_row(png_ptr, dsp_row,
 621                      png_pass_dsp_mask[png_ptr->pass]);
 622                png_read_finish_row(png_ptr);
 623                return;
 624             }
 625             break;
 626          case 2:
 627             if ((png_ptr->row_number & 0x07) != 4)
 628             {
 629                if (dsp_row != NULL && (png_ptr->row_number & 4))
 630                   png_combine_row(png_ptr, dsp_row,
 631                      png_pass_dsp_mask[png_ptr->pass]);
 632                png_read_finish_row(png_ptr);
 633                return;
 634             }
 635             break;
 636          case 3:
 637             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
 638             {
 639                if (dsp_row != NULL)
 640                   png_combine_row(png_ptr, dsp_row,
 641                      png_pass_dsp_mask[png_ptr->pass]);
 642                png_read_finish_row(png_ptr);
 643                return;
 644             }
 645             break;
 646          case 4:
 647             if ((png_ptr->row_number & 3) != 2)
 648             {
 649                if (dsp_row != NULL && (png_ptr->row_number & 2))
 650                   png_combine_row(png_ptr, dsp_row,
 651                      png_pass_dsp_mask[png_ptr->pass]);
 652                png_read_finish_row(png_ptr);
 653                return;
 654             }
 655             break;
 656          case 5:
 657             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
 658             {
 659                if (dsp_row != NULL)
 660                   png_combine_row(png_ptr, dsp_row,
 661                      png_pass_dsp_mask[png_ptr->pass]);
 662                png_read_finish_row(png_ptr);
 663                return;
 664             }
 665             break;
 666          case 6:
 667             if (!(png_ptr->row_number & 1))
 668             {
 669                png_read_finish_row(png_ptr);
 670                return;
 671             }
 672             break;
 673       }
 674    }
 675 #endif
 676
 677    if (!(png_ptr->mode & PNG_HAVE_IDAT))
 678       png_error(png_ptr, "Invalid attempt to read row data");
 679
 680    png_ptr->zstream.next_out = png_ptr->row_buf;
 681    png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
 682    do
 683    {
 684       if (!(png_ptr->zstream.avail_in))
 685       {
 686          while (!png_ptr->idat_size)
 687          {
 688             png_byte chunk_length[4];
 689
 690             png_crc_finish(png_ptr, 0);
 691
 692             png_read_data(png_ptr, chunk_length, 4);
 693             png_ptr->idat_size = png_get_uint_31(png_ptr,chunk_length);
 694
 695             png_reset_crc(png_ptr);
 696             png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 697             if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 698                png_error(png_ptr, "Not enough image data");
 699          }
 700          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
 701          png_ptr->zstream.next_in = png_ptr->zbuf;
 702          if (png_ptr->zbuf_size > png_ptr->idat_size)
 703             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
 704          png_crc_read(png_ptr, png_ptr->zbuf,
 705             (png_size_t)png_ptr->zstream.avail_in);
 706          png_ptr->idat_size -= png_ptr->zstream.avail_in;
 707       }
 708       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 709       if (ret == Z_STREAM_END)
 710       {
 711          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
 712             png_ptr->idat_size)
 713             png_error(png_ptr, "Extra compressed data");
 714          png_ptr->mode |= PNG_AFTER_IDAT;
 715          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 716          break;
 717       }
 718       if (ret != Z_OK)
 719          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
 720                    "Decompression error");
 721
 722    } while (png_ptr->zstream.avail_out);
 723
 724    png_ptr->row_info.color_type = png_ptr->color_type;
 725    png_ptr->row_info.width = png_ptr->iwidth;
 726    png_ptr->row_info.channels = png_ptr->channels;
 727    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 728    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 729    png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
 730        png_ptr->row_info.width);
 731
 732    if(png_ptr->row_buf[0])
 733    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 734       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 735       (int)(png_ptr->row_buf[0]));
 736
 737    png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
 738       png_ptr->rowbytes + 1);
 739
 740 #if defined(PNG_MNG_FEATURES_SUPPORTED)
 741    if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
 742       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
 743    {
 744       /* Intrapixel differencing */
 745       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
 746    }
 747 #endif
 748
 749
 750    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
 751       png_do_read_transformations(png_ptr);
 752
 753 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 754    /* blow up interlaced rows to full size */
 755    if (png_ptr->interlaced &&
 756       (png_ptr->transformations & PNG_INTERLACE))
 757    {
 758       if (png_ptr->pass < 6)
 759 /*       old interface (pre-1.0.9):
 760          png_do_read_interlace(&(png_ptr->row_info),
 761             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 762  */
 763          png_do_read_interlace(png_ptr);
 764
 765       if (dsp_row != NULL)
 766          png_combine_row(png_ptr, dsp_row,
 767             png_pass_dsp_mask[png_ptr->pass]);
 768       if (row != NULL)
 769          png_combine_row(png_ptr, row,
 770             png_pass_mask[png_ptr->pass]);
 771    }
 772    else
 773 #endif
 774    {
 775       if (row != NULL)
 776          png_combine_row(png_ptr, row, 0xff);
 777       if (dsp_row != NULL)
 778          png_combine_row(png_ptr, dsp_row, 0xff);
 779    }
 780    png_read_finish_row(png_ptr);
 781
 782    if (png_ptr->read_row_fn != NULL)
 783       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
 784 }
 785 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 786
 787 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 788 /* Read one or more rows of image data.  If the image is interlaced,
 789  * and png_set_interlace_handling() has been called, the rows need to
 790  * contain the contents of the rows from the previous pass.  If the
 791  * image has alpha or transparency, and png_handle_alpha()[*] has been
 792  * called, the rows contents must be initialized to the contents of the
 793  * screen.
 794  *
 795  * "row" holds the actual image, and pixels are placed in it
 796  * as they arrive.  If the image is displayed after each pass, it will
 797  * appear to "sparkle" in.  "display_row" can be used to display a
 798  * "chunky" progressive image, with finer detail added as it becomes
 799  * available.  If you do not want this "chunky" display, you may pass
 800  * NULL for display_row.  If you do not want the sparkle display, and
 801  * you have not called png_handle_alpha(), you may pass NULL for rows.
 802  * If you have called png_handle_alpha(), and the image has either an
 803  * alpha channel or a transparency chunk, you must provide a buffer for
 804  * rows.  In this case, you do not have to provide a display_row buffer
 805  * also, but you may.  If the image is not interlaced, or if you have
 806  * not called png_set_interlace_handling(), the display_row buffer will
 807  * be ignored, so pass NULL to it.
 808  *
 809  * [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.8
 810  */
 811
 812 void PNGAPI
 813 png_read_rows(png_structp png_ptr, png_bytepp row,
 814    png_bytepp display_row, png_uint_32 num_rows)
 815 {
 816    png_uint_32 i;
 817    png_bytepp rp;
 818    png_bytepp dp;
 819
 820    png_debug(1, "in png_read_rows\n");
 821    rp = row;
 822    dp = display_row;
 823    if (rp != NULL && dp != NULL)
 824       for (i = 0; i < num_rows; i++)
 825       {
 826          png_bytep rptr = *rp++;
 827          png_bytep dptr = *dp++;
 828
 829          png_read_row(png_ptr, rptr, dptr);
 830       }
 831    else if(rp != NULL)
 832       for (i = 0; i < num_rows; i++)
 833       {
 834          png_bytep rptr = *rp;
 835          png_read_row(png_ptr, rptr, png_bytep_NULL);
 836          rp++;
 837       }
 838    else if(dp != NULL)
 839       for (i = 0; i < num_rows; i++)
 840       {
 841          png_bytep dptr = *dp;
 842          png_read_row(png_ptr, png_bytep_NULL, dptr);
 843          dp++;
 844       }
 845 }
 846 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 847
 848 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 849 /* Read the entire image.  If the image has an alpha channel or a tRNS
 850  * chunk, and you have called png_handle_alpha()[*], you will need to
 851  * initialize the image to the current image that PNG will be overlaying.
 852  * We set the num_rows again here, in case it was incorrectly set in
 853  * png_read_start_row() by a call to png_read_update_info() or
 854  * png_start_read_image() if png_set_interlace_handling() wasn't called
 855  * prior to either of these functions like it should have been.  You can
 856  * only call this function once.  If you desire to have an image for
 857  * each pass of a interlaced image, use png_read_rows() instead.
 858  *
 859  * [*] png_handle_alpha() does not exist yet, as of libpng version 1.2.8
 860  */
 861 void PNGAPI
 862 png_read_image(png_structp png_ptr, png_bytepp image)
 863 {
 864    png_uint_32 i,image_height;
 865    int pass, j;
 866    png_bytepp rp;
 867
 868    png_debug(1, "in png_read_image\n");
 869
 870 #ifdef PNG_READ_INTERLACING_SUPPORTED
 871    pass = png_set_interlace_handling(png_ptr);
 872 #else
 873    if (png_ptr->interlaced)
 874       png_error(png_ptr,
 875         "Cannot read interlaced image -- interlace handler disabled.");
 876    pass = 1;
 877 #endif
 878
 879
 880    image_height=png_ptr->height;
 881    png_ptr->num_rows = image_height; /* Make sure this is set correctly */
 882
 883    for (j = 0; j < pass; j++)
 884    {
 885       rp = image;
 886       for (i = 0; i < image_height; i++)
 887       {
 888          png_read_row(png_ptr, *rp, png_bytep_NULL);
 889          rp++;
 890       }
 891    }
 892 }
 893 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 894
 895 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 896 /* Read the end of the PNG file.  Will not read past the end of the
 897  * file, will verify the end is accurate, and will read any comments
 898  * or time information at the end of the file, if info is not NULL.
 899  */
 900 void PNGAPI
 901 png_read_end(png_structp png_ptr, png_infop info_ptr)
 902 {
 903    png_byte chunk_length[4];
 904    png_uint_32 length;
 905
 906    png_debug(1, "in png_read_end\n");
 907    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 908
 909    do
 910    {
 911 #ifdef PNG_USE_LOCAL_ARRAYS
 912       PNG_IHDR;
 913       PNG_IDAT;
 914       PNG_IEND;
 915       PNG_PLTE;
 916 #if defined(PNG_READ_bKGD_SUPPORTED)
 917       PNG_bKGD;
 918 #endif
 919 #if defined(PNG_READ_cHRM_SUPPORTED)
 920       PNG_cHRM;
 921 #endif
 922 #if defined(PNG_READ_gAMA_SUPPORTED)
 923       PNG_gAMA;
 924 #endif
 925 #if defined(PNG_READ_hIST_SUPPORTED)
 926       PNG_hIST;
 927 #endif
 928 #if defined(PNG_READ_iCCP_SUPPORTED)
 929       PNG_iCCP;
 930 #endif
 931 #if defined(PNG_READ_iTXt_SUPPORTED)
 932       PNG_iTXt;
 933 #endif
 934 #if defined(PNG_READ_oFFs_SUPPORTED)
 935       PNG_oFFs;
 936 #endif
 937 #if defined(PNG_READ_pCAL_SUPPORTED)
 938       PNG_pCAL;
 939 #endif
 940 #if defined(PNG_READ_pHYs_SUPPORTED)
 941       PNG_pHYs;
 942 #endif
 943 #if defined(PNG_READ_sBIT_SUPPORTED)
 944       PNG_sBIT;
 945 #endif
 946 #if defined(PNG_READ_sCAL_SUPPORTED)
 947       PNG_sCAL;
 948 #endif
 949 #if defined(PNG_READ_sPLT_SUPPORTED)
 950       PNG_sPLT;
 951 #endif
 952 #if defined(PNG_READ_sRGB_SUPPORTED)
 953       PNG_sRGB;
 954 #endif
 955 #if defined(PNG_READ_tEXt_SUPPORTED)
 956       PNG_tEXt;
 957 #endif
 958 #if defined(PNG_READ_tIME_SUPPORTED)
 959       PNG_tIME;
 960 #endif
 961 #if defined(PNG_READ_tRNS_SUPPORTED)
 962       PNG_tRNS;
 963 #endif
 964 #if defined(PNG_READ_zTXt_SUPPORTED)
 965       PNG_zTXt;
 966 #endif
 967 #endif /* PNG_USE_LOCAL_ARRAYS */
 968
 969       png_read_data(png_ptr, chunk_length, 4);
 970       length = png_get_uint_31(png_ptr,chunk_length);
 971
 972       png_reset_crc(png_ptr);
 973       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 974
 975       png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);
 976
 977       if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
 978          png_handle_IHDR(png_ptr, info_ptr, length);
 979       else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
 980          png_handle_IEND(png_ptr, info_ptr, length);
 981 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 982       else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
 983       {
 984          if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 985          {
 986             if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
 987                png_error(png_ptr, "Too many IDAT's found");
 988          }
 989          else
 990             png_ptr->mode |= PNG_AFTER_IDAT;
 991          png_handle_unknown(png_ptr, info_ptr, length);
 992          if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 993             png_ptr->mode |= PNG_HAVE_PLTE;
 994       }
 995 #endif
 996       else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 997       {
 998          /* Zero length IDATs are legal after the last IDAT has been
 999           * read, but not after other chunks have been read.
1000           */
1001          if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
1002             png_error(png_ptr, "Too many IDAT's found");
1003          png_crc_finish(png_ptr, length);
1004       }
1005       else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
1006          png_handle_PLTE(png_ptr, info_ptr, length);
1007 #if defined(PNG_READ_bKGD_SUPPORTED)
1008       else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
1009          png_handle_bKGD(png_ptr, info_ptr, length);
1010 #endif
1011 #if defined(PNG_READ_cHRM_SUPPORTED)
1012       else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
1013          png_handle_cHRM(png_ptr, info_ptr, length);
1014 #endif
1015 #if defined(PNG_READ_gAMA_SUPPORTED)
1016       else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
1017          png_handle_gAMA(png_ptr, info_ptr, length);
1018 #endif
1019 #if defined(PNG_READ_hIST_SUPPORTED)
1020       else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
1021          png_handle_hIST(png_ptr, info_ptr, length);
1022 #endif
1023 #if defined(PNG_READ_oFFs_SUPPORTED)
1024       else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
1025          png_handle_oFFs(png_ptr, info_ptr, length);
1026 #endif
1027 #if defined(PNG_READ_pCAL_SUPPORTED)
1028       else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
1029          png_handle_pCAL(png_ptr, info_ptr, length);
1030 #endif
1031 #if defined(PNG_READ_sCAL_SUPPORTED)
1032       else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
1033          png_handle_sCAL(png_ptr, info_ptr, length);
1034 #endif
1035 #if defined(PNG_READ_pHYs_SUPPORTED)
1036       else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
1037          png_handle_pHYs(png_ptr, info_ptr, length);
1038 #endif
1039 #if defined(PNG_READ_sBIT_SUPPORTED)
1040       else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
1041          png_handle_sBIT(png_ptr, info_ptr, length);
1042 #endif
1043 #if defined(PNG_READ_sRGB_SUPPORTED)
1044       else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
1045          png_handle_sRGB(png_ptr, info_ptr, length);
1046 #endif
1047 #if defined(PNG_READ_iCCP_SUPPORTED)
1048       else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
1049          png_handle_iCCP(png_ptr, info_ptr, length);
1050 #endif
1051 #if defined(PNG_READ_sPLT_SUPPORTED)
1052       else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
1053          png_handle_sPLT(png_ptr, info_ptr, length);
1054 #endif
1055 #if defined(PNG_READ_tEXt_SUPPORTED)
1056       else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
1057          png_handle_tEXt(png_ptr, info_ptr, length);
1058 #endif
1059 #if defined(PNG_READ_tIME_SUPPORTED)
1060       else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
1061          png_handle_tIME(png_ptr, info_ptr, length);
1062 #endif
1063 #if defined(PNG_READ_tRNS_SUPPORTED)
1064       else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
1065          png_handle_tRNS(png_ptr, info_ptr, length);
1066 #endif
1067 #if defined(PNG_READ_zTXt_SUPPORTED)
1068       else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
1069          png_handle_zTXt(png_ptr, info_ptr, length);
1070 #endif
1071 #if defined(PNG_READ_iTXt_SUPPORTED)
1072       else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
1073          png_handle_iTXt(png_ptr, info_ptr, length);
1074 #endif
1075       else
1076          png_handle_unknown(png_ptr, info_ptr, length);
1077    } while (!(png_ptr->mode & PNG_HAVE_IEND));
1078 }
1079 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
1080
1081 /* free all memory used by the read */
1082 void PNGAPI
1083 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1084    png_infopp end_info_ptr_ptr)
1085 {
1086    png_structp png_ptr = NULL;
1087    png_infop info_ptr = NULL, end_info_ptr = NULL;
1088 #ifdef PNG_USER_MEM_SUPPORTED
1089    png_free_ptr free_fn;
1090    png_voidp mem_ptr;
1091 #endif
1092
1093    png_debug(1, "in png_destroy_read_struct\n");
1094    if (png_ptr_ptr != NULL)
1095       png_ptr = *png_ptr_ptr;
1096
1097    if (info_ptr_ptr != NULL)
1098       info_ptr = *info_ptr_ptr;
1099
1100    if (end_info_ptr_ptr != NULL)
1101       end_info_ptr = *end_info_ptr_ptr;
1102
1103 #ifdef PNG_USER_MEM_SUPPORTED
1104    free_fn = png_ptr->free_fn;
1105    mem_ptr = png_ptr->mem_ptr;
1106 #endif
1107
1108    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1109
1110    if (info_ptr != NULL)
1111    {
1112 #if defined(PNG_TEXT_SUPPORTED)
1113       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1114 #endif
1115
1116 #ifdef PNG_USER_MEM_SUPPORTED
1117       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1118           (png_voidp)mem_ptr);
1119 #else
1120       png_destroy_struct((png_voidp)info_ptr);
1121 #endif
1122       *info_ptr_ptr = NULL;
1123    }
1124
1125    if (end_info_ptr != NULL)
1126    {
1127 #if defined(PNG_READ_TEXT_SUPPORTED)
1128       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1129 #endif
1130 #ifdef PNG_USER_MEM_SUPPORTED
1131       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1132          (png_voidp)mem_ptr);
1133 #else
1134       png_destroy_struct((png_voidp)end_info_ptr);
1135 #endif
1136       *end_info_ptr_ptr = NULL;
1137    }
1138
1139    if (png_ptr != NULL)
1140    {
1141 #ifdef PNG_USER_MEM_SUPPORTED
1142       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1143           (png_voidp)mem_ptr);
1144 #else
1145       png_destroy_struct((png_voidp)png_ptr);
1146 #endif
1147       *png_ptr_ptr = NULL;
1148    }
1149 }
1150
1151 /* free all memory used by the read (old method) */
1152 void /* PRIVATE */
1153 png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
1154 {
1155 #ifdef PNG_SETJMP_SUPPORTED
1156    jmp_buf tmp_jmp;
1157 #endif
1158    png_error_ptr error_fn;
1159    png_error_ptr warning_fn;
1160    png_voidp error_ptr;
1161 #ifdef PNG_USER_MEM_SUPPORTED
1162    png_free_ptr free_fn;
1163 #endif
1164
1165    png_debug(1, "in png_read_destroy\n");
1166    if (info_ptr != NULL)
1167       png_info_destroy(png_ptr, info_ptr);
1168
1169    if (end_info_ptr != NULL)
1170       png_info_destroy(png_ptr, end_info_ptr);
1171
1172    png_free(png_ptr, png_ptr->zbuf);
1173    png_free(png_ptr, png_ptr->big_row_buf);
1174    png_free(png_ptr, png_ptr->prev_row);
1175 #if defined(PNG_READ_DITHER_SUPPORTED)
1176    png_free(png_ptr, png_ptr->palette_lookup);
1177    png_free(png_ptr, png_ptr->dither_index);
1178 #endif
1179 #if defined(PNG_READ_GAMMA_SUPPORTED)
1180    png_free(png_ptr, png_ptr->gamma_table);
1181 #endif
1182 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
1183    png_free(png_ptr, png_ptr->gamma_from_1);
1184    png_free(png_ptr, png_ptr->gamma_to_1);
1185 #endif
1186 #ifdef PNG_FREE_ME_SUPPORTED
1187    if (png_ptr->free_me & PNG_FREE_PLTE)
1188       png_zfree(png_ptr, png_ptr->palette);
1189    png_ptr->free_me &= ~PNG_FREE_PLTE;
1190 #else
1191    if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
1192       png_zfree(png_ptr, png_ptr->palette);
1193    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
1194 #endif
1195 #if defined(PNG_tRNS_SUPPORTED) || \
1196     defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1197 #ifdef PNG_FREE_ME_SUPPORTED
1198    if (png_ptr->free_me & PNG_FREE_TRNS)
1199       png_free(png_ptr, png_ptr->trans);
1200    png_ptr->free_me &= ~PNG_FREE_TRNS;
1201 #else
1202    if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
1203       png_free(png_ptr, png_ptr->trans);
1204    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
1205 #endif
1206 #endif
1207 #if defined(PNG_READ_hIST_SUPPORTED)
1208 #ifdef PNG_FREE_ME_SUPPORTED
1209    if (png_ptr->free_me & PNG_FREE_HIST)
1210       png_free(png_ptr, png_ptr->hist);
1211    png_ptr->free_me &= ~PNG_FREE_HIST;
1212 #else
1213    if (png_ptr->flags & PNG_FLAG_FREE_HIST)
1214       png_free(png_ptr, png_ptr->hist);
1215    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
1216 #endif
1217 #endif
1218 #if defined(PNG_READ_GAMMA_SUPPORTED)
1219    if (png_ptr->gamma_16_table != NULL)
1220    {
1221       int i;
1222       int istop = (1 << (8 - png_ptr->gamma_shift));
1223       for (i = 0; i < istop; i++)
1224       {
1225          png_free(png_ptr, png_ptr->gamma_16_table[i]);
1226       }
1227    png_free(png_ptr, png_ptr->gamma_16_table);
1228    }
1229 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
1230    if (png_ptr->gamma_16_from_1 != NULL)
1231    {
1232       int i;
1233       int istop = (1 << (8 - png_ptr->gamma_shift));
1234       for (i = 0; i < istop; i++)
1235       {
1236          png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1237       }
1238    png_free(png_ptr, png_ptr->gamma_16_from_1);
1239    }
1240    if (png_ptr->gamma_16_to_1 != NULL)
1241    {
1242       int i;
1243       int istop = (1 << (8 - png_ptr->gamma_shift));
1244       for (i = 0; i < istop; i++)
1245       {
1246          png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1247       }
1248    png_free(png_ptr, png_ptr->gamma_16_to_1);
1249    }
1250 #endif
1251 #endif
1252 #if defined(PNG_TIME_RFC1123_SUPPORTED)
1253    png_free(png_ptr, png_ptr->time_buffer);
1254 #endif
1255
1256    inflateEnd(&png_ptr->zstream);
1257 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1258    png_free(png_ptr, png_ptr->save_buffer);
1259 #endif
1260
1261 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1262 #ifdef PNG_TEXT_SUPPORTED
1263    png_free(png_ptr, png_ptr->current_text);
1264 #endif /* PNG_TEXT_SUPPORTED */
1265 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1266
1267    /* Save the important info out of the png_struct, in case it is
1268     * being used again.
1269     */
1270 #ifdef PNG_SETJMP_SUPPORTED
1271    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
1272 #endif
1273
1274    error_fn = png_ptr->error_fn;
1275    warning_fn = png_ptr->warning_fn;
1276    error_ptr = png_ptr->error_ptr;
1277 #ifdef PNG_USER_MEM_SUPPORTED
1278    free_fn = png_ptr->free_fn;
1279 #endif
1280
1281    png_memset(png_ptr, 0, png_sizeof (png_struct));
1282
1283    png_ptr->error_fn = error_fn;
1284    png_ptr->warning_fn = warning_fn;
1285    png_ptr->error_ptr = error_ptr;
1286 #ifdef PNG_USER_MEM_SUPPORTED
1287    png_ptr->free_fn = free_fn;
1288 #endif
1289
1290 #ifdef PNG_SETJMP_SUPPORTED
1291    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
1292 #endif
1293
1294 }
1295
1296 void PNGAPI
1297 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1298 {
1299    png_ptr->read_row_fn = read_row_fn;
1300 }
1301
1302
1303 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
1304 #if defined(PNG_INFO_IMAGE_SUPPORTED)
1305 void PNGAPI
1306 png_read_png(png_structp png_ptr, png_infop info_ptr,
1307                            int transforms,
1308                            voidp params)
1309 {
1310    int row;
1311
1312 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
1313    /* invert the alpha channel from opacity to transparency
1314     */
1315    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1316        png_set_invert_alpha(png_ptr);
1317 #endif
1318
1319    /* png_read_info() gives us all of the information from the
1320     * PNG file before the first IDAT (image data chunk).
1321     */
1322    png_read_info(png_ptr, info_ptr);
1323    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1324       png_error(png_ptr,"Image is too high to process with png_read_png()");
1325
1326    /* -------------- image transformations start here ------------------- */
1327
1328 #if defined(PNG_READ_16_TO_8_SUPPORTED)
1329    /* tell libpng to strip 16 bit/color files down to 8 bits per color
1330     */
1331    if (transforms & PNG_TRANSFORM_STRIP_16)
1332        png_set_strip_16(png_ptr);
1333 #endif
1334
1335 #if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1336    /* Strip alpha bytes from the input data without combining with
1337     * the background (not recommended).
1338     */
1339    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1340        png_set_strip_alpha(png_ptr);
1341 #endif
1342
1343 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1344    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1345     * byte into separate bytes (useful for paletted and grayscale images).
1346     */
1347    if (transforms & PNG_TRANSFORM_PACKING)
1348        png_set_packing(png_ptr);
1349 #endif
1350
1351 #if defined(PNG_READ_PACKSWAP_SUPPORTED)
1352    /* Change the order of packed pixels to least significant bit first
1353     * (not useful if you are using png_set_packing).
1354     */
1355    if (transforms & PNG_TRANSFORM_PACKSWAP)
1356        png_set_packswap(png_ptr);
1357 #endif
1358
1359 #if defined(PNG_READ_EXPAND_SUPPORTED)
1360    /* Expand paletted colors into true RGB triplets
1361     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1362     * Expand paletted or RGB images with transparency to full alpha
1363     * channels so the data will be available as RGBA quartets.
1364     */
1365    if (transforms & PNG_TRANSFORM_EXPAND)
1366        if ((png_ptr->bit_depth < 8) ||
1367            (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1368            (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1369          png_set_expand(png_ptr);
1370 #endif
1371
1372    /* We don't handle background color or gamma transformation or dithering.
1373     */
1374
1375 #if defined(PNG_READ_INVERT_SUPPORTED)
1376    /* invert monochrome files to have 0 as white and 1 as black
1377     */
1378    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1379        png_set_invert_mono(png_ptr);
1380 #endif
1381
1382 #if defined(PNG_READ_SHIFT_SUPPORTED)
1383    /* If you want to shift the pixel values from the range [0,255] or
1384     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1385     * colors were originally in:
1386     */
1387    if ((transforms & PNG_TRANSFORM_SHIFT)
1388        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1389    {
1390       png_color_8p sig_bit;
1391
1392       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1393       png_set_shift(png_ptr, sig_bit);
1394    }
1395 #endif
1396
1397 #if defined(PNG_READ_BGR_SUPPORTED)
1398    /* flip the RGB pixels to BGR (or RGBA to BGRA)
1399     */
1400    if (transforms & PNG_TRANSFORM_BGR)
1401        png_set_bgr(png_ptr);
1402 #endif
1403
1404 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
1405    /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1406     */
1407    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1408        png_set_swap_alpha(png_ptr);
1409 #endif
1410
1411 #if defined(PNG_READ_SWAP_SUPPORTED)
1412    /* swap bytes of 16 bit files to least significant byte first
1413     */
1414    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1415        png_set_swap(png_ptr);
1416 #endif
1417
1418    /* We don't handle adding filler bytes */
1419
1420    /* Optional call to gamma correct and add the background to the palette
1421     * and update info structure.  REQUIRED if you are expecting libpng to
1422     * update the palette for you (i.e., you selected such a transform above).
1423     */
1424    png_read_update_info(png_ptr, info_ptr);
1425
1426    /* -------------- image transformations end here ------------------- */
1427
1428 #ifdef PNG_FREE_ME_SUPPORTED
1429    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1430 #endif
1431    if(info_ptr->row_pointers == NULL)
1432    {
1433       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1434          info_ptr->height * png_sizeof(png_bytep));
1435 #ifdef PNG_FREE_ME_SUPPORTED
1436       info_ptr->free_me |= PNG_FREE_ROWS;
1437 #endif
1438       for (row = 0; row < (int)info_ptr->height; row++)
1439       {
1440          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1441             png_get_rowbytes(png_ptr, info_ptr));
1442       }
1443    }
1444
1445    png_read_image(png_ptr, info_ptr->row_pointers);
1446    info_ptr->valid |= PNG_INFO_IDAT;
1447
1448    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
1449    png_read_end(png_ptr, info_ptr);
1450
1451    if(transforms == 0 || params == NULL)
1452       /* quiet compiler warnings */ return;
1453
1454 }
1455 #endif
1456 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */