src/png/pngread.c

   1
   2 /* pngread.c - read a PNG file
   3  *
   4  * Last changed in libpng 1.2.30 [August 15, 2008]
   5  * For conditions of distribution and use, see copyright notice in png.h
   6  * Copyright (c) 1998-2008 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 #if defined(PNG_READ_SUPPORTED)
  17
  18 /* Create a PNG structure for reading, and allocate any memory needed. */
  19 png_structp PNGAPI
  20 png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
  21    png_error_ptr error_fn, png_error_ptr warn_fn)
  22 {
  23
  24 #ifdef PNG_USER_MEM_SUPPORTED
  25    return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
  26       warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
  27 }
  28
  29 /* Alternate create PNG structure for reading, and allocate any memory needed. */
  30 png_structp PNGAPI
  31 png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
  32    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
  33    png_malloc_ptr malloc_fn, png_free_ptr free_fn)
  34 {
  35 #endif /* PNG_USER_MEM_SUPPORTED */
  36
  37 #ifdef PNG_SETJMP_SUPPORTED
  38    volatile
  39 #endif
  40    png_structp png_ptr;
  41
  42 #ifdef PNG_SETJMP_SUPPORTED
  43 #ifdef USE_FAR_KEYWORD
  44    jmp_buf jmpbuf;
  45 #endif
  46 #endif
  47
  48    int i;
  49
  50    png_debug(1, "in png_create_read_struct");
  51 #ifdef PNG_USER_MEM_SUPPORTED
  52    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
  53       (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
  54 #else
  55    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
  56 #endif
  57    if (png_ptr == NULL)
  58       return (NULL);
  59
  60    /* added at libpng-1.2.6 */
  61 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
  62    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
  63    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
  64 #endif
  65
  66 #ifdef PNG_SETJMP_SUPPORTED
  67 #ifdef USE_FAR_KEYWORD
  68    if (setjmp(jmpbuf))
  69 #else
  70    if (setjmp(png_ptr->jmpbuf))
  71 #endif
  72    {
  73       png_free(png_ptr, png_ptr->zbuf);
  74       png_ptr->zbuf = NULL;
  75 #ifdef PNG_USER_MEM_SUPPORTED
  76       png_destroy_struct_2((png_voidp)png_ptr,
  77          (png_free_ptr)free_fn, (png_voidp)mem_ptr);
  78 #else
  79       png_destroy_struct((png_voidp)png_ptr);
  80 #endif
  81       return (NULL);
  82    }
  83 #ifdef USE_FAR_KEYWORD
  84    png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf));
  85 #endif
  86 #endif
  87
  88 #ifdef PNG_USER_MEM_SUPPORTED
  89    png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
  90 #endif
  91
  92    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
  93
  94    if (user_png_ver)
  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    else
 104         png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 105
 106
 107    if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
 108    {
 109      /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
 110       * we must recompile any applications that use any older library version.
 111       * For versions after libpng 1.0, we will be compatible, so we need
 112       * only check the first digit.
 113       */
 114      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
 115          (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
 116          (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
 117      {
 118 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
 119         char msg[80];
 120         if (user_png_ver)
 121         {
 122           png_snprintf(msg, 80,
 123              "Application was compiled with png.h from libpng-%.20s",
 124              user_png_ver);
 125           png_warning(png_ptr, msg);
 126         }
 127         png_snprintf(msg, 80,
 128              "Application  is  running with png.c from libpng-%.20s",
 129            png_libpng_ver);
 130         png_warning(png_ptr, msg);
 131 #endif
 132 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 133         png_ptr->flags = 0;
 134 #endif
 135         png_error(png_ptr,
 136            "Incompatible libpng version in application and library");
 137      }
 138    }
 139
 140    /* initialize zbuf - compression buffer */
 141    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 142    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
 143      (png_uint_32)png_ptr->zbuf_size);
 144    png_ptr->zstream.zalloc = png_zalloc;
 145    png_ptr->zstream.zfree = png_zfree;
 146    png_ptr->zstream.opaque = (voidpf)png_ptr;
 147
 148    switch (inflateInit(&png_ptr->zstream))
 149    {
 150      case Z_OK: /* Do nothing */ break;
 151      case Z_MEM_ERROR:
 152      case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
 153      case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
 154      default: png_error(png_ptr, "Unknown zlib error");
 155    }
 156
 157    png_ptr->zstream.next_out = png_ptr->zbuf;
 158    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 159
 160    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
 161
 162 #ifdef PNG_SETJMP_SUPPORTED
 163 /* Applications that neglect to set up their own setjmp() and then encounter
 164    a png_error() will longjmp here.  Since the jmpbuf is then meaningless we
 165    abort instead of returning. */
 166 #ifdef USE_FAR_KEYWORD
 167    if (setjmp(jmpbuf))
 168       PNG_ABORT();
 169    png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf));
 170 #else
 171    if (setjmp(png_ptr->jmpbuf))
 172       PNG_ABORT();
 173 #endif
 174 #endif
 175    return (png_ptr);
 176 }
 177
 178 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
 179 /* Initialize PNG structure for reading, and allocate any memory needed.
 180    This interface is deprecated in favour of the png_create_read_struct(),
 181    and it will disappear as of libpng-1.3.0. */
 182 #undef png_read_init
 183 void PNGAPI
 184 png_read_init(png_structp png_ptr)
 185 {
 186    /* We only come here via pre-1.0.7-compiled applications */
 187    png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
 188 }
 189
 190 void PNGAPI
 191 png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
 192    png_size_t png_struct_size, png_size_t png_info_size)
 193 {
 194    /* We only come here via pre-1.0.12-compiled applications */
 195    if (png_ptr == NULL) return;
 196 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
 197    if (png_sizeof(png_struct) > png_struct_size ||
 198       png_sizeof(png_info) > png_info_size)
 199    {
 200       char msg[80];
 201       png_ptr->warning_fn = NULL;
 202       if (user_png_ver)
 203       {
 204         png_snprintf(msg, 80,
 205            "Application was compiled with png.h from libpng-%.20s",
 206            user_png_ver);
 207         png_warning(png_ptr, msg);
 208       }
 209       png_snprintf(msg, 80,
 210          "Application  is  running with png.c from libpng-%.20s",
 211          png_libpng_ver);
 212       png_warning(png_ptr, msg);
 213    }
 214 #endif
 215    if (png_sizeof(png_struct) > png_struct_size)
 216      {
 217        png_ptr->error_fn = NULL;
 218 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 219        png_ptr->flags = 0;
 220 #endif
 221        png_error(png_ptr,
 222        "The png struct allocated by the application for reading is too small.");
 223      }
 224    if (png_sizeof(png_info) > png_info_size)
 225      {
 226        png_ptr->error_fn = NULL;
 227 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 228        png_ptr->flags = 0;
 229 #endif
 230        png_error(png_ptr,
 231          "The info struct allocated by application for reading is too small.");
 232      }
 233    png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
 234 }
 235 #endif /* PNG_1_0_X || PNG_1_2_X */
 236
 237 void PNGAPI
 238 png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
 239    png_size_t png_struct_size)
 240 {
 241 #ifdef PNG_SETJMP_SUPPORTED
 242    jmp_buf tmp_jmp;  /* to save current jump buffer */
 243 #endif
 244
 245    int i = 0;
 246
 247    png_structp png_ptr=*ptr_ptr;
 248
 249    if (png_ptr == NULL) return;
 250
 251    do
 252    {
 253      if (user_png_ver[i] != png_libpng_ver[i])
 254      {
 255 #ifdef PNG_LEGACY_SUPPORTED
 256        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 257 #else
 258        png_ptr->warning_fn = NULL;
 259        png_warning(png_ptr,
 260         "Application uses deprecated png_read_init() and should be recompiled.");
 261        break;
 262 #endif
 263      }
 264    } while (png_libpng_ver[i++]);
 265
 266    png_debug(1, "in png_read_init_3");
 267
 268 #ifdef PNG_SETJMP_SUPPORTED
 269    /* save jump buffer and error functions */
 270    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
 271 #endif
 272
 273    if (png_sizeof(png_struct) > png_struct_size)
 274    {
 275       png_destroy_struct(png_ptr);
 276       *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
 277       png_ptr = *ptr_ptr;
 278    }
 279
 280    /* reset all variables to 0 */
 281    png_memset(png_ptr, 0, png_sizeof(png_struct));
 282
 283 #ifdef PNG_SETJMP_SUPPORTED
 284    /* restore jump buffer */
 285    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
 286 #endif
 287
 288    /* added at libpng-1.2.6 */
 289 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
 290    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
 291    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 292 #endif
 293
 294    /* initialize zbuf - compression buffer */
 295    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 296    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
 297      (png_uint_32)png_ptr->zbuf_size);
 298    png_ptr->zstream.zalloc = png_zalloc;
 299    png_ptr->zstream.zfree = png_zfree;
 300    png_ptr->zstream.opaque = (voidpf)png_ptr;
 301
 302    switch (inflateInit(&png_ptr->zstream))
 303    {
 304      case Z_OK: /* Do nothing */ break;
 305      case Z_MEM_ERROR:
 306      case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
 307      case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
 308      default: png_error(png_ptr, "Unknown zlib error");
 309    }
 310
 311    png_ptr->zstream.next_out = png_ptr->zbuf;
 312    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 313
 314    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
 315 }
 316
 317 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 318 /* Read the information before the actual image data.  This has been
 319  * changed in v0.90 to allow reading a file that already has the magic
 320  * bytes read from the stream.  You can tell libpng how many bytes have
 321  * been read from the beginning of the stream (up to the maximum of 8)
 322  * via png_set_sig_bytes(), and we will only check the remaining bytes
 323  * here.  The application can then have access to the signature bytes we
 324  * read if it is determined that this isn't a valid PNG file.
 325  */
 326 void PNGAPI
 327 png_read_info(png_structp png_ptr, png_infop info_ptr)
 328 {
 329    if (png_ptr == NULL || info_ptr == NULL) return;
 330    png_debug(1, "in png_read_info");
 331    /* If we haven't checked all of the PNG signature bytes, do so now. */
 332    if (png_ptr->sig_bytes < 8)
 333    {
 334       png_size_t num_checked = png_ptr->sig_bytes,
 335                  num_to_check = 8 - num_checked;
 336
 337       png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
 338       png_ptr->sig_bytes = 8;
 339
 340       if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
 341       {
 342          if (num_checked < 4 &&
 343              png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
 344             png_error(png_ptr, "Not a PNG file");
 345          else
 346             png_error(png_ptr, "PNG file corrupted by ASCII conversion");
 347       }
 348       if (num_checked < 3)
 349          png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
 350    }
 351
 352    for (;;)
 353    {
 354 #ifdef PNG_USE_LOCAL_ARRAYS
 355       PNG_CONST PNG_IHDR;
 356       PNG_CONST PNG_IDAT;
 357       PNG_CONST PNG_IEND;
 358       PNG_CONST PNG_PLTE;
 359 #if defined(PNG_READ_bKGD_SUPPORTED)
 360       PNG_CONST PNG_bKGD;
 361 #endif
 362 #if defined(PNG_READ_cHRM_SUPPORTED)
 363       PNG_CONST PNG_cHRM;
 364 #endif
 365 #if defined(PNG_READ_gAMA_SUPPORTED)
 366       PNG_CONST PNG_gAMA;
 367 #endif
 368 #if defined(PNG_READ_hIST_SUPPORTED)
 369       PNG_CONST PNG_hIST;
 370 #endif
 371 #if defined(PNG_READ_iCCP_SUPPORTED)
 372       PNG_CONST PNG_iCCP;
 373 #endif
 374 #if defined(PNG_READ_iTXt_SUPPORTED)
 375       PNG_CONST PNG_iTXt;
 376 #endif
 377 #if defined(PNG_READ_oFFs_SUPPORTED)
 378       PNG_CONST PNG_oFFs;
 379 #endif
 380 #if defined(PNG_READ_pCAL_SUPPORTED)
 381       PNG_CONST PNG_pCAL;
 382 #endif
 383 #if defined(PNG_READ_pHYs_SUPPORTED)
 384       PNG_CONST PNG_pHYs;
 385 #endif
 386 #if defined(PNG_READ_sBIT_SUPPORTED)
 387       PNG_CONST PNG_sBIT;
 388 #endif
 389 #if defined(PNG_READ_sCAL_SUPPORTED)
 390       PNG_CONST PNG_sCAL;
 391 #endif
 392 #if defined(PNG_READ_sPLT_SUPPORTED)
 393       PNG_CONST PNG_sPLT;
 394 #endif
 395 #if defined(PNG_READ_sRGB_SUPPORTED)
 396       PNG_CONST PNG_sRGB;
 397 #endif
 398 #if defined(PNG_READ_tEXt_SUPPORTED)
 399       PNG_CONST PNG_tEXt;
 400 #endif
 401 #if defined(PNG_READ_tIME_SUPPORTED)
 402       PNG_CONST PNG_tIME;
 403 #endif
 404 #if defined(PNG_READ_tRNS_SUPPORTED)
 405       PNG_CONST PNG_tRNS;
 406 #endif
 407 #if defined(PNG_READ_zTXt_SUPPORTED)
 408       PNG_CONST PNG_zTXt;
 409 #endif
 410 #endif /* PNG_USE_LOCAL_ARRAYS */
 411       png_uint_32 length = png_read_chunk_header(png_ptr);
 412       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
 413
 414       /* This should be a binary subdivision search or a hash for
 415        * matching the chunk name rather than a linear search.
 416        */
 417       if (!png_memcmp(chunk_name, png_IDAT, 4))
 418         if (png_ptr->mode & PNG_AFTER_IDAT)
 419           png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 420
 421       if (!png_memcmp(chunk_name, png_IHDR, 4))
 422          png_handle_IHDR(png_ptr, info_ptr, length);
 423       else if (!png_memcmp(chunk_name, png_IEND, 4))
 424          png_handle_IEND(png_ptr, info_ptr, length);
 425 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 426       else if (png_handle_as_unknown(png_ptr, chunk_name))
 427       {
 428          if (!png_memcmp(chunk_name, png_IDAT, 4))
 429             png_ptr->mode |= PNG_HAVE_IDAT;
 430          png_handle_unknown(png_ptr, info_ptr, length);
 431          if (!png_memcmp(chunk_name, png_PLTE, 4))
 432             png_ptr->mode |= PNG_HAVE_PLTE;
 433          else if (!png_memcmp(chunk_name, png_IDAT, 4))
 434          {
 435             if (!(png_ptr->mode & PNG_HAVE_IHDR))
 436                png_error(png_ptr, "Missing IHDR before IDAT");
 437             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 438                      !(png_ptr->mode & PNG_HAVE_PLTE))
 439                png_error(png_ptr, "Missing PLTE before IDAT");
 440             break;
 441          }
 442       }
 443 #endif
 444       else if (!png_memcmp(chunk_name, png_PLTE, 4))
 445          png_handle_PLTE(png_ptr, info_ptr, length);
 446       else if (!png_memcmp(chunk_name, png_IDAT, 4))
 447       {
 448          if (!(png_ptr->mode & PNG_HAVE_IHDR))
 449             png_error(png_ptr, "Missing IHDR before IDAT");
 450          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 451                   !(png_ptr->mode & PNG_HAVE_PLTE))
 452             png_error(png_ptr, "Missing PLTE before IDAT");
 453
 454          png_ptr->idat_size = length;
 455          png_ptr->mode |= PNG_HAVE_IDAT;
 456          break;
 457       }
 458 #if defined(PNG_READ_bKGD_SUPPORTED)
 459       else if (!png_memcmp(chunk_name, png_bKGD, 4))
 460          png_handle_bKGD(png_ptr, info_ptr, length);
 461 #endif
 462 #if defined(PNG_READ_cHRM_SUPPORTED)
 463       else if (!png_memcmp(chunk_name, png_cHRM, 4))
 464          png_handle_cHRM(png_ptr, info_ptr, length);
 465 #endif
 466 #if defined(PNG_READ_gAMA_SUPPORTED)
 467       else if (!png_memcmp(chunk_name, png_gAMA, 4))
 468          png_handle_gAMA(png_ptr, info_ptr, length);
 469 #endif
 470 #if defined(PNG_READ_hIST_SUPPORTED)
 471       else if (!png_memcmp(chunk_name, png_hIST, 4))
 472          png_handle_hIST(png_ptr, info_ptr, length);
 473 #endif
 474 #if defined(PNG_READ_oFFs_SUPPORTED)
 475       else if (!png_memcmp(chunk_name, png_oFFs, 4))
 476          png_handle_oFFs(png_ptr, info_ptr, length);
 477 #endif
 478 #if defined(PNG_READ_pCAL_SUPPORTED)
 479       else if (!png_memcmp(chunk_name, png_pCAL, 4))
 480          png_handle_pCAL(png_ptr, info_ptr, length);
 481 #endif
 482 #if defined(PNG_READ_sCAL_SUPPORTED)
 483       else if (!png_memcmp(chunk_name, png_sCAL, 4))
 484          png_handle_sCAL(png_ptr, info_ptr, length);
 485 #endif
 486 #if defined(PNG_READ_pHYs_SUPPORTED)
 487       else if (!png_memcmp(chunk_name, png_pHYs, 4))
 488          png_handle_pHYs(png_ptr, info_ptr, length);
 489 #endif
 490 #if defined(PNG_READ_sBIT_SUPPORTED)
 491       else if (!png_memcmp(chunk_name, png_sBIT, 4))
 492          png_handle_sBIT(png_ptr, info_ptr, length);
 493 #endif
 494 #if defined(PNG_READ_sRGB_SUPPORTED)
 495       else if (!png_memcmp(chunk_name, png_sRGB, 4))
 496          png_handle_sRGB(png_ptr, info_ptr, length);
 497 #endif
 498 #if defined(PNG_READ_iCCP_SUPPORTED)
 499       else if (!png_memcmp(chunk_name, png_iCCP, 4))
 500          png_handle_iCCP(png_ptr, info_ptr, length);
 501 #endif
 502 #if defined(PNG_READ_sPLT_SUPPORTED)
 503       else if (!png_memcmp(chunk_name, png_sPLT, 4))
 504          png_handle_sPLT(png_ptr, info_ptr, length);
 505 #endif
 506 #if defined(PNG_READ_tEXt_SUPPORTED)
 507       else if (!png_memcmp(chunk_name, png_tEXt, 4))
 508          png_handle_tEXt(png_ptr, info_ptr, length);
 509 #endif
 510 #if defined(PNG_READ_tIME_SUPPORTED)
 511       else if (!png_memcmp(chunk_name, png_tIME, 4))
 512          png_handle_tIME(png_ptr, info_ptr, length);
 513 #endif
 514 #if defined(PNG_READ_tRNS_SUPPORTED)
 515       else if (!png_memcmp(chunk_name, png_tRNS, 4))
 516          png_handle_tRNS(png_ptr, info_ptr, length);
 517 #endif
 518 #if defined(PNG_READ_zTXt_SUPPORTED)
 519       else if (!png_memcmp(chunk_name, png_zTXt, 4))
 520          png_handle_zTXt(png_ptr, info_ptr, length);
 521 #endif
 522 #if defined(PNG_READ_iTXt_SUPPORTED)
 523       else if (!png_memcmp(chunk_name, png_iTXt, 4))
 524          png_handle_iTXt(png_ptr, info_ptr, length);
 525 #endif
 526       else
 527          png_handle_unknown(png_ptr, info_ptr, length);
 528    }
 529 }
 530 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 531
 532 /* optional call to update the users info_ptr structure */
 533 void PNGAPI
 534 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 535 {
 536    png_debug(1, "in png_read_update_info");
 537    if (png_ptr == NULL) return;
 538    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 539       png_read_start_row(png_ptr);
 540    else
 541       png_warning(png_ptr,
 542       "Ignoring extra png_read_update_info() call; row buffer not reallocated");
 543    png_read_transform_info(png_ptr, info_ptr);
 544 }
 545
 546 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 547 /* Initialize palette, background, etc, after transformations
 548  * are set, but before any reading takes place.  This allows
 549  * the user to obtain a gamma-corrected palette, for example.
 550  * If the user doesn't call this, we will do it ourselves.
 551  */
 552 void PNGAPI
 553 png_start_read_image(png_structp png_ptr)
 554 {
 555    png_debug(1, "in png_start_read_image");
 556    if (png_ptr == NULL) return;
 557    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 558       png_read_start_row(png_ptr);
 559 }
 560 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 561
 562 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 563 void PNGAPI
 564 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 565 {
 566 #ifdef PNG_USE_LOCAL_ARRAYS
 567    PNG_CONST PNG_IDAT;
 568    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
 569       0xff};
 570    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 571 #endif
 572    int ret;
 573    if (png_ptr == NULL) return;
 574    png_debug2(1, "in png_read_row (row %lu, pass %d)",
 575       png_ptr->row_number, png_ptr->pass);
 576    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 577       png_read_start_row(png_ptr);
 578    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
 579    {
 580    /* check for transforms that have been set but were defined out */
 581 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
 582    if (png_ptr->transformations & PNG_INVERT_MONO)
 583       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
 584 #endif
 585 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
 586    if (png_ptr->transformations & PNG_FILLER)
 587       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
 588 #endif
 589 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
 590    if (png_ptr->transformations & PNG_PACKSWAP)
 591       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
 592 #endif
 593 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
 594    if (png_ptr->transformations & PNG_PACK)
 595       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
 596 #endif
 597 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
 598    if (png_ptr->transformations & PNG_SHIFT)
 599       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
 600 #endif
 601 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
 602    if (png_ptr->transformations & PNG_BGR)
 603       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
 604 #endif
 605 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
 606    if (png_ptr->transformations & PNG_SWAP_BYTES)
 607       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
 608 #endif
 609    }
 610
 611 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 612    /* if interlaced and we do not need a new row, combine row and return */
 613    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 614    {
 615       switch (png_ptr->pass)
 616       {
 617          case 0:
 618             if (png_ptr->row_number & 0x07)
 619             {
 620                if (dsp_row != NULL)
 621                   png_combine_row(png_ptr, dsp_row,
 622                      png_pass_dsp_mask[png_ptr->pass]);
 623                png_read_finish_row(png_ptr);
 624                return;
 625             }
 626             break;
 627          case 1:
 628             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
 629             {
 630                if (dsp_row != NULL)
 631                   png_combine_row(png_ptr, dsp_row,
 632                      png_pass_dsp_mask[png_ptr->pass]);
 633                png_read_finish_row(png_ptr);
 634                return;
 635             }
 636             break;
 637          case 2:
 638             if ((png_ptr->row_number & 0x07) != 4)
 639             {
 640                if (dsp_row != NULL && (png_ptr->row_number & 4))
 641                   png_combine_row(png_ptr, dsp_row,
 642                      png_pass_dsp_mask[png_ptr->pass]);
 643                png_read_finish_row(png_ptr);
 644                return;
 645             }
 646             break;
 647          case 3:
 648             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
 649             {
 650                if (dsp_row != NULL)
 651                   png_combine_row(png_ptr, dsp_row,
 652                      png_pass_dsp_mask[png_ptr->pass]);
 653                png_read_finish_row(png_ptr);
 654                return;
 655             }
 656             break;
 657          case 4:
 658             if ((png_ptr->row_number & 3) != 2)
 659             {
 660                if (dsp_row != NULL && (png_ptr->row_number & 2))
 661                   png_combine_row(png_ptr, dsp_row,
 662                      png_pass_dsp_mask[png_ptr->pass]);
 663                png_read_finish_row(png_ptr);
 664                return;
 665             }
 666             break;
 667          case 5:
 668             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
 669             {
 670                if (dsp_row != NULL)
 671                   png_combine_row(png_ptr, dsp_row,
 672                      png_pass_dsp_mask[png_ptr->pass]);
 673                png_read_finish_row(png_ptr);
 674                return;
 675             }
 676             break;
 677          case 6:
 678             if (!(png_ptr->row_number & 1))
 679             {
 680                png_read_finish_row(png_ptr);
 681                return;
 682             }
 683             break;
 684       }
 685    }
 686 #endif
 687
 688    if (!(png_ptr->mode & PNG_HAVE_IDAT))
 689       png_error(png_ptr, "Invalid attempt to read row data");
 690
 691    png_ptr->zstream.next_out = png_ptr->row_buf;
 692    png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
 693    do
 694    {
 695       if (!(png_ptr->zstream.avail_in))
 696       {
 697          while (!png_ptr->idat_size)
 698          {
 699             png_crc_finish(png_ptr, 0);
 700
 701             png_ptr->idat_size = png_read_chunk_header(png_ptr);
 702             if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 703                png_error(png_ptr, "Not enough image data");
 704          }
 705          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
 706          png_ptr->zstream.next_in = png_ptr->zbuf;
 707          if (png_ptr->zbuf_size > png_ptr->idat_size)
 708             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
 709          png_crc_read(png_ptr, png_ptr->zbuf,
 710             (png_size_t)png_ptr->zstream.avail_in);
 711          png_ptr->idat_size -= png_ptr->zstream.avail_in;
 712       }
 713       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 714       if (ret == Z_STREAM_END)
 715       {
 716          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
 717             png_ptr->idat_size)
 718             png_error(png_ptr, "Extra compressed data");
 719          png_ptr->mode |= PNG_AFTER_IDAT;
 720          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 721          break;
 722       }
 723       if (ret != Z_OK)
 724          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
 725                    "Decompression error");
 726
 727    } while (png_ptr->zstream.avail_out);
 728
 729    png_ptr->row_info.color_type = png_ptr->color_type;
 730    png_ptr->row_info.width = png_ptr->iwidth;
 731    png_ptr->row_info.channels = png_ptr->channels;
 732    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 733    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 734    png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
 735        png_ptr->row_info.width);
 736
 737    if (png_ptr->row_buf[0])
 738    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 739       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 740       (int)(png_ptr->row_buf[0]));
 741
 742    png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
 743       png_ptr->rowbytes + 1);
 744
 745 #if defined(PNG_MNG_FEATURES_SUPPORTED)
 746    if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
 747       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
 748    {
 749       /* Intrapixel differencing */
 750       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
 751    }
 752 #endif
 753
 754
 755    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
 756       png_do_read_transformations(png_ptr);
 757
 758 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 759    /* blow up interlaced rows to full size */
 760    if (png_ptr->interlaced &&
 761       (png_ptr->transformations & PNG_INTERLACE))
 762    {
 763       if (png_ptr->pass < 6)
 764 /*       old interface (pre-1.0.9):
 765          png_do_read_interlace(&(png_ptr->row_info),
 766             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 767  */
 768          png_do_read_interlace(png_ptr);
 769
 770       if (dsp_row != NULL)
 771          png_combine_row(png_ptr, dsp_row,
 772             png_pass_dsp_mask[png_ptr->pass]);
 773       if (row != NULL)
 774          png_combine_row(png_ptr, row,
 775             png_pass_mask[png_ptr->pass]);
 776    }
 777    else
 778 #endif
 779    {
 780       if (row != NULL)
 781          png_combine_row(png_ptr, row, 0xff);
 782       if (dsp_row != NULL)
 783          png_combine_row(png_ptr, dsp_row, 0xff);
 784    }
 785    png_read_finish_row(png_ptr);
 786
 787    if (png_ptr->read_row_fn != NULL)
 788       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
 789 }
 790 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 791
 792 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 793 /* Read one or more rows of image data.  If the image is interlaced,
 794  * and png_set_interlace_handling() has been called, the rows need to
 795  * contain the contents of the rows from the previous pass.  If the
 796  * image has alpha or transparency, and png_handle_alpha()[*] has been
 797  * called, the rows contents must be initialized to the contents of the
 798  * screen.
 799  *
 800  * "row" holds the actual image, and pixels are placed in it
 801  * as they arrive.  If the image is displayed after each pass, it will
 802  * appear to "sparkle" in.  "display_row" can be used to display a
 803  * "chunky" progressive image, with finer detail added as it becomes
 804  * available.  If you do not want this "chunky" display, you may pass
 805  * NULL for display_row.  If you do not want the sparkle display, and
 806  * you have not called png_handle_alpha(), you may pass NULL for rows.
 807  * If you have called png_handle_alpha(), and the image has either an
 808  * alpha channel or a transparency chunk, you must provide a buffer for
 809  * rows.  In this case, you do not have to provide a display_row buffer
 810  * also, but you may.  If the image is not interlaced, or if you have
 811  * not called png_set_interlace_handling(), the display_row buffer will
 812  * be ignored, so pass NULL to it.
 813  *
 814  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 815  */
 816
 817 void PNGAPI
 818 png_read_rows(png_structp png_ptr, png_bytepp row,
 819    png_bytepp display_row, png_uint_32 num_rows)
 820 {
 821    png_uint_32 i;
 822    png_bytepp rp;
 823    png_bytepp dp;
 824
 825    png_debug(1, "in png_read_rows");
 826    if (png_ptr == NULL) return;
 827    rp = row;
 828    dp = display_row;
 829    if (rp != NULL && dp != NULL)
 830       for (i = 0; i < num_rows; i++)
 831       {
 832          png_bytep rptr = *rp++;
 833          png_bytep dptr = *dp++;
 834
 835          png_read_row(png_ptr, rptr, dptr);
 836       }
 837    else if (rp != NULL)
 838       for (i = 0; i < num_rows; i++)
 839       {
 840          png_bytep rptr = *rp;
 841          png_read_row(png_ptr, rptr, png_bytep_NULL);
 842          rp++;
 843       }
 844    else if (dp != NULL)
 845       for (i = 0; i < num_rows; i++)
 846       {
 847          png_bytep dptr = *dp;
 848          png_read_row(png_ptr, png_bytep_NULL, dptr);
 849          dp++;
 850       }
 851 }
 852 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 853
 854 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 855 /* Read the entire image.  If the image has an alpha channel or a tRNS
 856  * chunk, and you have called png_handle_alpha()[*], you will need to
 857  * initialize the image to the current image that PNG will be overlaying.
 858  * We set the num_rows again here, in case it was incorrectly set in
 859  * png_read_start_row() by a call to png_read_update_info() or
 860  * png_start_read_image() if png_set_interlace_handling() wasn't called
 861  * prior to either of these functions like it should have been.  You can
 862  * only call this function once.  If you desire to have an image for
 863  * each pass of a interlaced image, use png_read_rows() instead.
 864  *
 865  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 866  */
 867 void PNGAPI
 868 png_read_image(png_structp png_ptr, png_bytepp image)
 869 {
 870    png_uint_32 i, image_height;
 871    int pass, j;
 872    png_bytepp rp;
 873
 874    png_debug(1, "in png_read_image");
 875    if (png_ptr == NULL) return;
 876
 877 #ifdef PNG_READ_INTERLACING_SUPPORTED
 878    pass = png_set_interlace_handling(png_ptr);
 879 #else
 880    if (png_ptr->interlaced)
 881       png_error(png_ptr,
 882         "Cannot read interlaced image -- interlace handler disabled.");
 883    pass = 1;
 884 #endif
 885
 886
 887    image_height=png_ptr->height;
 888    png_ptr->num_rows = image_height; /* Make sure this is set correctly */
 889
 890    for (j = 0; j < pass; j++)
 891    {
 892       rp = image;
 893       for (i = 0; i < image_height; i++)
 894       {
 895          png_read_row(png_ptr, *rp, png_bytep_NULL);
 896          rp++;
 897       }
 898    }
 899 }
 900 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 901
 902 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 903 /* Read the end of the PNG file.  Will not read past the end of the
 904  * file, will verify the end is accurate, and will read any comments
 905  * or time information at the end of the file, if info is not NULL.
 906  */
 907 void PNGAPI
 908 png_read_end(png_structp png_ptr, png_infop info_ptr)
 909 {
 910    png_debug(1, "in png_read_end");
 911    if (png_ptr == NULL) return;
 912    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 913
 914    do
 915    {
 916 #ifdef PNG_USE_LOCAL_ARRAYS
 917       PNG_CONST PNG_IHDR;
 918       PNG_CONST PNG_IDAT;
 919       PNG_CONST PNG_IEND;
 920       PNG_CONST PNG_PLTE;
 921 #if defined(PNG_READ_bKGD_SUPPORTED)
 922       PNG_CONST PNG_bKGD;
 923 #endif
 924 #if defined(PNG_READ_cHRM_SUPPORTED)
 925       PNG_CONST PNG_cHRM;
 926 #endif
 927 #if defined(PNG_READ_gAMA_SUPPORTED)
 928       PNG_CONST PNG_gAMA;
 929 #endif
 930 #if defined(PNG_READ_hIST_SUPPORTED)
 931       PNG_CONST PNG_hIST;
 932 #endif
 933 #if defined(PNG_READ_iCCP_SUPPORTED)
 934       PNG_CONST PNG_iCCP;
 935 #endif
 936 #if defined(PNG_READ_iTXt_SUPPORTED)
 937       PNG_CONST PNG_iTXt;
 938 #endif
 939 #if defined(PNG_READ_oFFs_SUPPORTED)
 940       PNG_CONST PNG_oFFs;
 941 #endif
 942 #if defined(PNG_READ_pCAL_SUPPORTED)
 943       PNG_CONST PNG_pCAL;
 944 #endif
 945 #if defined(PNG_READ_pHYs_SUPPORTED)
 946       PNG_CONST PNG_pHYs;
 947 #endif
 948 #if defined(PNG_READ_sBIT_SUPPORTED)
 949       PNG_CONST PNG_sBIT;
 950 #endif
 951 #if defined(PNG_READ_sCAL_SUPPORTED)
 952       PNG_CONST PNG_sCAL;
 953 #endif
 954 #if defined(PNG_READ_sPLT_SUPPORTED)
 955       PNG_CONST PNG_sPLT;
 956 #endif
 957 #if defined(PNG_READ_sRGB_SUPPORTED)
 958       PNG_CONST PNG_sRGB;
 959 #endif
 960 #if defined(PNG_READ_tEXt_SUPPORTED)
 961       PNG_CONST PNG_tEXt;
 962 #endif
 963 #if defined(PNG_READ_tIME_SUPPORTED)
 964       PNG_CONST PNG_tIME;
 965 #endif
 966 #if defined(PNG_READ_tRNS_SUPPORTED)
 967       PNG_CONST PNG_tRNS;
 968 #endif
 969 #if defined(PNG_READ_zTXt_SUPPORTED)
 970       PNG_CONST PNG_zTXt;
 971 #endif
 972 #endif /* PNG_USE_LOCAL_ARRAYS */
 973       png_uint_32 length = png_read_chunk_header(png_ptr);
 974       PNG_CONST png_bytep chunk_name = png_ptr->chunk_name;
 975
 976       if (!png_memcmp(chunk_name, png_IHDR, 4))
 977          png_handle_IHDR(png_ptr, info_ptr, length);
 978       else if (!png_memcmp(chunk_name, png_IEND, 4))
 979          png_handle_IEND(png_ptr, info_ptr, length);
 980 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 981       else if (png_handle_as_unknown(png_ptr, chunk_name))
 982       {
 983          if (!png_memcmp(chunk_name, png_IDAT, 4))
 984          {
 985             if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 986                png_error(png_ptr, "Too many IDAT's found");
 987          }
 988          png_handle_unknown(png_ptr, info_ptr, length);
 989          if (!png_memcmp(chunk_name, png_PLTE, 4))
 990             png_ptr->mode |= PNG_HAVE_PLTE;
 991       }
 992 #endif
 993       else if (!png_memcmp(chunk_name, png_IDAT, 4))
 994       {
 995          /* Zero length IDATs are legal after the last IDAT has been
 996           * read, but not after other chunks have been read.
 997           */
 998          if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 999             png_error(png_ptr, "Too many IDAT's found");
1000          png_crc_finish(png_ptr, length);
1001       }
1002       else if (!png_memcmp(chunk_name, png_PLTE, 4))
1003          png_handle_PLTE(png_ptr, info_ptr, length);
1004 #if defined(PNG_READ_bKGD_SUPPORTED)
1005       else if (!png_memcmp(chunk_name, png_bKGD, 4))
1006          png_handle_bKGD(png_ptr, info_ptr, length);
1007 #endif
1008 #if defined(PNG_READ_cHRM_SUPPORTED)
1009       else if (!png_memcmp(chunk_name, png_cHRM, 4))
1010          png_handle_cHRM(png_ptr, info_ptr, length);
1011 #endif
1012 #if defined(PNG_READ_gAMA_SUPPORTED)
1013       else if (!png_memcmp(chunk_name, png_gAMA, 4))
1014          png_handle_gAMA(png_ptr, info_ptr, length);
1015 #endif
1016 #if defined(PNG_READ_hIST_SUPPORTED)
1017       else if (!png_memcmp(chunk_name, png_hIST, 4))
1018          png_handle_hIST(png_ptr, info_ptr, length);
1019 #endif
1020 #if defined(PNG_READ_oFFs_SUPPORTED)
1021       else if (!png_memcmp(chunk_name, png_oFFs, 4))
1022          png_handle_oFFs(png_ptr, info_ptr, length);
1023 #endif
1024 #if defined(PNG_READ_pCAL_SUPPORTED)
1025       else if (!png_memcmp(chunk_name, png_pCAL, 4))
1026          png_handle_pCAL(png_ptr, info_ptr, length);
1027 #endif
1028 #if defined(PNG_READ_sCAL_SUPPORTED)
1029       else if (!png_memcmp(chunk_name, png_sCAL, 4))
1030          png_handle_sCAL(png_ptr, info_ptr, length);
1031 #endif
1032 #if defined(PNG_READ_pHYs_SUPPORTED)
1033       else if (!png_memcmp(chunk_name, png_pHYs, 4))
1034          png_handle_pHYs(png_ptr, info_ptr, length);
1035 #endif
1036 #if defined(PNG_READ_sBIT_SUPPORTED)
1037       else if (!png_memcmp(chunk_name, png_sBIT, 4))
1038          png_handle_sBIT(png_ptr, info_ptr, length);
1039 #endif
1040 #if defined(PNG_READ_sRGB_SUPPORTED)
1041       else if (!png_memcmp(chunk_name, png_sRGB, 4))
1042          png_handle_sRGB(png_ptr, info_ptr, length);
1043 #endif
1044 #if defined(PNG_READ_iCCP_SUPPORTED)
1045       else if (!png_memcmp(chunk_name, png_iCCP, 4))
1046          png_handle_iCCP(png_ptr, info_ptr, length);
1047 #endif
1048 #if defined(PNG_READ_sPLT_SUPPORTED)
1049       else if (!png_memcmp(chunk_name, png_sPLT, 4))
1050          png_handle_sPLT(png_ptr, info_ptr, length);
1051 #endif
1052 #if defined(PNG_READ_tEXt_SUPPORTED)
1053       else if (!png_memcmp(chunk_name, png_tEXt, 4))
1054          png_handle_tEXt(png_ptr, info_ptr, length);
1055 #endif
1056 #if defined(PNG_READ_tIME_SUPPORTED)
1057       else if (!png_memcmp(chunk_name, png_tIME, 4))
1058          png_handle_tIME(png_ptr, info_ptr, length);
1059 #endif
1060 #if defined(PNG_READ_tRNS_SUPPORTED)
1061       else if (!png_memcmp(chunk_name, png_tRNS, 4))
1062          png_handle_tRNS(png_ptr, info_ptr, length);
1063 #endif
1064 #if defined(PNG_READ_zTXt_SUPPORTED)
1065       else if (!png_memcmp(chunk_name, png_zTXt, 4))
1066          png_handle_zTXt(png_ptr, info_ptr, length);
1067 #endif
1068 #if defined(PNG_READ_iTXt_SUPPORTED)
1069       else if (!png_memcmp(chunk_name, png_iTXt, 4))
1070          png_handle_iTXt(png_ptr, info_ptr, length);
1071 #endif
1072       else
1073          png_handle_unknown(png_ptr, info_ptr, length);
1074    } while (!(png_ptr->mode & PNG_HAVE_IEND));
1075 }
1076 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
1077
1078 /* free all memory used by the read */
1079 void PNGAPI
1080 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1081    png_infopp end_info_ptr_ptr)
1082 {
1083    png_structp png_ptr = NULL;
1084    png_infop info_ptr = NULL, end_info_ptr = NULL;
1085 #ifdef PNG_USER_MEM_SUPPORTED
1086    png_free_ptr free_fn = NULL;
1087    png_voidp mem_ptr = NULL;
1088 #endif
1089
1090    png_debug(1, "in png_destroy_read_struct");
1091    if (png_ptr_ptr != NULL)
1092       png_ptr = *png_ptr_ptr;
1093    if (png_ptr == NULL)
1094       return;
1095
1096 #ifdef PNG_USER_MEM_SUPPORTED
1097    free_fn = png_ptr->free_fn;
1098    mem_ptr = png_ptr->mem_ptr;
1099 #endif
1100
1101    if (info_ptr_ptr != NULL)
1102       info_ptr = *info_ptr_ptr;
1103
1104    if (end_info_ptr_ptr != NULL)
1105       end_info_ptr = *end_info_ptr_ptr;
1106
1107    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1108
1109    if (info_ptr != NULL)
1110    {
1111 #if defined(PNG_TEXT_SUPPORTED)
1112       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1113 #endif
1114
1115 #ifdef PNG_USER_MEM_SUPPORTED
1116       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1117           (png_voidp)mem_ptr);
1118 #else
1119       png_destroy_struct((png_voidp)info_ptr);
1120 #endif
1121       *info_ptr_ptr = NULL;
1122    }
1123
1124    if (end_info_ptr != NULL)
1125    {
1126 #if defined(PNG_READ_TEXT_SUPPORTED)
1127       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1128 #endif
1129 #ifdef PNG_USER_MEM_SUPPORTED
1130       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1131          (png_voidp)mem_ptr);
1132 #else
1133       png_destroy_struct((png_voidp)end_info_ptr);
1134 #endif
1135       *end_info_ptr_ptr = NULL;
1136    }
1137
1138    if (png_ptr != NULL)
1139    {
1140 #ifdef PNG_USER_MEM_SUPPORTED
1141       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1142           (png_voidp)mem_ptr);
1143 #else
1144       png_destroy_struct((png_voidp)png_ptr);
1145 #endif
1146       *png_ptr_ptr = NULL;
1147    }
1148 }
1149
1150 /* free all memory used by the read (old method) */
1151 void /* PRIVATE */
1152 png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
1153 {
1154 #ifdef PNG_SETJMP_SUPPORTED
1155    jmp_buf tmp_jmp;
1156 #endif
1157    png_error_ptr error_fn;
1158    png_error_ptr warning_fn;
1159    png_voidp error_ptr;
1160 #ifdef PNG_USER_MEM_SUPPORTED
1161    png_free_ptr free_fn;
1162 #endif
1163
1164    png_debug(1, "in png_read_destroy");
1165    if (info_ptr != NULL)
1166       png_info_destroy(png_ptr, info_ptr);
1167
1168    if (end_info_ptr != NULL)
1169       png_info_destroy(png_ptr, end_info_ptr);
1170
1171    png_free(png_ptr, png_ptr->zbuf);
1172    png_free(png_ptr, png_ptr->big_row_buf);
1173    png_free(png_ptr, png_ptr->prev_row);
1174    png_free(png_ptr, png_ptr->chunkdata);
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    if (png_ptr == NULL) return;
1300    png_ptr->read_row_fn = read_row_fn;
1301 }
1302
1303
1304 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
1305 #if defined(PNG_INFO_IMAGE_SUPPORTED)
1306 void PNGAPI
1307 png_read_png(png_structp png_ptr, png_infop info_ptr,
1308                            int transforms,
1309                            voidp params)
1310 {
1311    int row;
1312
1313    if (png_ptr == NULL) return;
1314 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
1315    /* invert the alpha channel from opacity to transparency
1316     */
1317    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1318        png_set_invert_alpha(png_ptr);
1319 #endif
1320
1321    /* png_read_info() gives us all of the information from the
1322     * PNG file before the first IDAT (image data chunk).
1323     */
1324    png_read_info(png_ptr, info_ptr);
1325    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1326       png_error(png_ptr, "Image is too high to process with png_read_png()");
1327
1328    /* -------------- image transformations start here ------------------- */
1329
1330 #if defined(PNG_READ_16_TO_8_SUPPORTED)
1331    /* tell libpng to strip 16 bit/color files down to 8 bits per color
1332     */
1333    if (transforms & PNG_TRANSFORM_STRIP_16)
1334        png_set_strip_16(png_ptr);
1335 #endif
1336
1337 #if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1338    /* Strip alpha bytes from the input data without combining with
1339     * the background (not recommended).
1340     */
1341    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1342        png_set_strip_alpha(png_ptr);
1343 #endif
1344
1345 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1346    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1347     * byte into separate bytes (useful for paletted and grayscale images).
1348     */
1349    if (transforms & PNG_TRANSFORM_PACKING)
1350        png_set_packing(png_ptr);
1351 #endif
1352
1353 #if defined(PNG_READ_PACKSWAP_SUPPORTED)
1354    /* Change the order of packed pixels to least significant bit first
1355     * (not useful if you are using png_set_packing).
1356     */
1357    if (transforms & PNG_TRANSFORM_PACKSWAP)
1358        png_set_packswap(png_ptr);
1359 #endif
1360
1361 #if defined(PNG_READ_EXPAND_SUPPORTED)
1362    /* Expand paletted colors into true RGB triplets
1363     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1364     * Expand paletted or RGB images with transparency to full alpha
1365     * channels so the data will be available as RGBA quartets.
1366     */
1367    if (transforms & PNG_TRANSFORM_EXPAND)
1368        if ((png_ptr->bit_depth < 8) ||
1369            (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1370            (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1371          png_set_expand(png_ptr);
1372 #endif
1373
1374    /* We don't handle background color or gamma transformation or dithering.
1375     */
1376
1377 #if defined(PNG_READ_INVERT_SUPPORTED)
1378    /* invert monochrome files to have 0 as white and 1 as black
1379     */
1380    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1381        png_set_invert_mono(png_ptr);
1382 #endif
1383
1384 #if defined(PNG_READ_SHIFT_SUPPORTED)
1385    /* If you want to shift the pixel values from the range [0,255] or
1386     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1387     * colors were originally in:
1388     */
1389    if ((transforms & PNG_TRANSFORM_SHIFT)
1390        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1391    {
1392       png_color_8p sig_bit;
1393
1394       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1395       png_set_shift(png_ptr, sig_bit);
1396    }
1397 #endif
1398
1399 #if defined(PNG_READ_BGR_SUPPORTED)
1400    /* flip the RGB pixels to BGR (or RGBA to BGRA)
1401     */
1402    if (transforms & PNG_TRANSFORM_BGR)
1403        png_set_bgr(png_ptr);
1404 #endif
1405
1406 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
1407    /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1408     */
1409    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1410        png_set_swap_alpha(png_ptr);
1411 #endif
1412
1413 #if defined(PNG_READ_SWAP_SUPPORTED)
1414    /* swap bytes of 16 bit files to least significant byte first
1415     */
1416    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1417        png_set_swap(png_ptr);
1418 #endif
1419
1420    /* We don't handle adding filler bytes */
1421
1422    /* Optional call to gamma correct and add the background to the palette
1423     * and update info structure.  REQUIRED if you are expecting libpng to
1424     * update the palette for you (i.e., you selected such a transform above).
1425     */
1426    png_read_update_info(png_ptr, info_ptr);
1427
1428    /* -------------- image transformations end here ------------------- */
1429
1430 #ifdef PNG_FREE_ME_SUPPORTED
1431    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1432 #endif
1433    if (info_ptr->row_pointers == NULL)
1434    {
1435       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1436          info_ptr->height * png_sizeof(png_bytep));
1437 #ifdef PNG_FREE_ME_SUPPORTED
1438       info_ptr->free_me |= PNG_FREE_ROWS;
1439 #endif
1440       for (row = 0; row < (int)info_ptr->height; row++)
1441       {
1442          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1443             png_get_rowbytes(png_ptr, info_ptr));
1444       }
1445    }
1446
1447    png_read_image(png_ptr, info_ptr->row_pointers);
1448    info_ptr->valid |= PNG_INFO_IDAT;
1449
1450    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
1451    png_read_end(png_ptr, info_ptr);
1452
1453    transforms = transforms; /* quiet compiler warnings */
1454    params = params;
1455
1456 }
1457 #endif /* PNG_INFO_IMAGE_SUPPORTED */
1458 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
1459 #endif /* PNG_READ_SUPPORTED */