src/png/pngread.c

   1
   2 /* pngread.c - read a PNG file
   3  *
   4  * Last changed in libpng 1.2.19 August 19, 2007
   5  * For conditions of distribution and use, see copyright notice in png.h
   6  * Copyright (c) 1998-2007 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 #if defined(PNG_READ_SUPPORTED)
  18
  19 /* Create a PNG structure for reading, and allocate any memory needed. */
  20 png_structp PNGAPI
  21 png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
  22    png_error_ptr error_fn, png_error_ptr warn_fn)
  23 {
  24
  25 #ifdef PNG_USER_MEM_SUPPORTED
  26    return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
  27       warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
  28 }
  29
  30 /* Alternate create PNG structure for reading, and allocate any memory needed. */
  31 png_structp PNGAPI
  32 png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
  33    png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
  34    png_malloc_ptr malloc_fn, png_free_ptr free_fn)
  35 {
  36 #endif /* PNG_USER_MEM_SUPPORTED */
  37
  38    png_structp png_ptr;
  39
  40 #ifdef PNG_SETJMP_SUPPORTED
  41 #ifdef USE_FAR_KEYWORD
  42    jmp_buf jmpbuf;
  43 #endif
  44 #endif
  45
  46    int i;
  47
  48    png_debug(1, "in png_create_read_struct\n");
  49 #ifdef PNG_USER_MEM_SUPPORTED
  50    png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
  51       (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
  52 #else
  53    png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
  54 #endif
  55    if (png_ptr == NULL)
  56       return (NULL);
  57
  58    /* added at libpng-1.2.6 */
  59 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
  60    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
  61    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
  62 #endif
  63
  64 #ifdef PNG_SETJMP_SUPPORTED
  65 #ifdef USE_FAR_KEYWORD
  66    if (setjmp(jmpbuf))
  67 #else
  68    if (setjmp(png_ptr->jmpbuf))
  69 #endif
  70    {
  71       png_free(png_ptr, png_ptr->zbuf);
  72       png_ptr->zbuf=NULL;
  73 #ifdef PNG_USER_MEM_SUPPORTED
  74       png_destroy_struct_2((png_voidp)png_ptr,
  75          (png_free_ptr)free_fn, (png_voidp)mem_ptr);
  76 #else
  77       png_destroy_struct((png_voidp)png_ptr);
  78 #endif
  79       return (NULL);
  80    }
  81 #ifdef USE_FAR_KEYWORD
  82    png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
  83 #endif
  84 #endif
  85
  86 #ifdef PNG_USER_MEM_SUPPORTED
  87    png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
  88 #endif
  89
  90    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
  91
  92    i=0;
  93    do
  94    {
  95      if(user_png_ver[i] != png_libpng_ver[i])
  96         png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
  97    } while (png_libpng_ver[i++]);
  98
  99    if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
 100    {
 101      /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
 102       * we must recompile any applications that use any older library version.
 103       * For versions after libpng 1.0, we will be compatible, so we need
 104       * only check the first digit.
 105       */
 106      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
 107          (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
 108          (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
 109      {
 110 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
 111         char msg[80];
 112         if (user_png_ver)
 113         {
 114           png_snprintf(msg, 80,
 115              "Application was compiled with png.h from libpng-%.20s",
 116              user_png_ver);
 117           png_warning(png_ptr, msg);
 118         }
 119         png_snprintf(msg, 80,
 120              "Application  is  running with png.c from libpng-%.20s",
 121            png_libpng_ver);
 122         png_warning(png_ptr, msg);
 123 #endif
 124 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 125         png_ptr->flags=0;
 126 #endif
 127         png_error(png_ptr,
 128            "Incompatible libpng version in application and library");
 129      }
 130    }
 131
 132    /* initialize zbuf - compression buffer */
 133    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 134    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
 135      (png_uint_32)png_ptr->zbuf_size);
 136    png_ptr->zstream.zalloc = png_zalloc;
 137    png_ptr->zstream.zfree = png_zfree;
 138    png_ptr->zstream.opaque = (voidpf)png_ptr;
 139
 140    switch (inflateInit(&png_ptr->zstream))
 141    {
 142      case Z_OK: /* Do nothing */ break;
 143      case Z_MEM_ERROR:
 144      case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
 145      case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
 146      default: png_error(png_ptr, "Unknown zlib error");
 147    }
 148
 149    png_ptr->zstream.next_out = png_ptr->zbuf;
 150    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 151
 152    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
 153
 154 #ifdef PNG_SETJMP_SUPPORTED
 155 /* Applications that neglect to set up their own setjmp() and then encounter
 156    a png_error() will longjmp here.  Since the jmpbuf is then meaningless we
 157    abort instead of returning. */
 158 #ifdef USE_FAR_KEYWORD
 159    if (setjmp(jmpbuf))
 160       PNG_ABORT();
 161    png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
 162 #else
 163    if (setjmp(png_ptr->jmpbuf))
 164       PNG_ABORT();
 165 #endif
 166 #endif
 167    return (png_ptr);
 168 }
 169
 170 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
 171 /* Initialize PNG structure for reading, and allocate any memory needed.
 172    This interface is deprecated in favour of the png_create_read_struct(),
 173    and it will disappear as of libpng-1.3.0. */
 174 #undef png_read_init
 175 void PNGAPI
 176 png_read_init(png_structp png_ptr)
 177 {
 178    /* We only come here via pre-1.0.7-compiled applications */
 179    png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
 180 }
 181
 182 void PNGAPI
 183 png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
 184    png_size_t png_struct_size, png_size_t png_info_size)
 185 {
 186    /* We only come here via pre-1.0.12-compiled applications */
 187    if(png_ptr == NULL) return;
 188 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
 189    if(png_sizeof(png_struct) > png_struct_size ||
 190       png_sizeof(png_info) > png_info_size)
 191    {
 192       char msg[80];
 193       png_ptr->warning_fn=NULL;
 194       if (user_png_ver)
 195       {
 196         png_snprintf(msg, 80,
 197            "Application was compiled with png.h from libpng-%.20s",
 198            user_png_ver);
 199         png_warning(png_ptr, msg);
 200       }
 201       png_snprintf(msg, 80,
 202          "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 #endif /* PNG_1_0_X || PNG_1_2_X */
 228
 229 void PNGAPI
 230 png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
 231    png_size_t png_struct_size)
 232 {
 233 #ifdef PNG_SETJMP_SUPPORTED
 234    jmp_buf tmp_jmp;  /* to save current jump buffer */
 235 #endif
 236
 237    int i=0;
 238
 239    png_structp png_ptr=*ptr_ptr;
 240
 241    if(png_ptr == NULL) return;
 242
 243    do
 244    {
 245      if(user_png_ver[i] != png_libpng_ver[i])
 246      {
 247 #ifdef PNG_LEGACY_SUPPORTED
 248        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
 249 #else
 250        png_ptr->warning_fn=NULL;
 251        png_warning(png_ptr,
 252         "Application uses deprecated png_read_init() and should be recompiled.");
 253        break;
 254 #endif
 255      }
 256    } while (png_libpng_ver[i++]);
 257
 258    png_debug(1, "in png_read_init_3\n");
 259
 260 #ifdef PNG_SETJMP_SUPPORTED
 261    /* save jump buffer and error functions */
 262    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
 263 #endif
 264
 265    if(png_sizeof(png_struct) > png_struct_size)
 266      {
 267        png_destroy_struct(png_ptr);
 268        *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
 269        png_ptr = *ptr_ptr;
 270      }
 271
 272    /* reset all variables to 0 */
 273    png_memset(png_ptr, 0, png_sizeof (png_struct));
 274
 275 #ifdef PNG_SETJMP_SUPPORTED
 276    /* restore jump buffer */
 277    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
 278 #endif
 279
 280    /* added at libpng-1.2.6 */
 281 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
 282    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
 283    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 284 #endif
 285
 286    /* initialize zbuf - compression buffer */
 287    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
 288    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
 289      (png_uint_32)png_ptr->zbuf_size);
 290    png_ptr->zstream.zalloc = png_zalloc;
 291    png_ptr->zstream.zfree = png_zfree;
 292    png_ptr->zstream.opaque = (voidpf)png_ptr;
 293
 294    switch (inflateInit(&png_ptr->zstream))
 295    {
 296      case Z_OK: /* Do nothing */ break;
 297      case Z_MEM_ERROR:
 298      case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
 299      case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
 300      default: png_error(png_ptr, "Unknown zlib error");
 301    }
 302
 303    png_ptr->zstream.next_out = png_ptr->zbuf;
 304    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 305
 306    png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
 307 }
 308
 309 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 310 /* Read the information before the actual image data.  This has been
 311  * changed in v0.90 to allow reading a file that already has the magic
 312  * bytes read from the stream.  You can tell libpng how many bytes have
 313  * been read from the beginning of the stream (up to the maximum of 8)
 314  * via png_set_sig_bytes(), and we will only check the remaining bytes
 315  * here.  The application can then have access to the signature bytes we
 316  * read if it is determined that this isn't a valid PNG file.
 317  */
 318 void PNGAPI
 319 png_read_info(png_structp png_ptr, png_infop info_ptr)
 320 {
 321    if(png_ptr == NULL) return;
 322    png_debug(1, "in png_read_info\n");
 323    /* If we haven't checked all of the PNG signature bytes, do so now. */
 324    if (png_ptr->sig_bytes < 8)
 325    {
 326       png_size_t num_checked = png_ptr->sig_bytes,
 327                  num_to_check = 8 - num_checked;
 328
 329       png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
 330       png_ptr->sig_bytes = 8;
 331
 332       if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
 333       {
 334          if (num_checked < 4 &&
 335              png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
 336             png_error(png_ptr, "Not a PNG file");
 337          else
 338             png_error(png_ptr, "PNG file corrupted by ASCII conversion");
 339       }
 340       if (num_checked < 3)
 341          png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
 342    }
 343
 344    for(;;)
 345    {
 346 #ifdef PNG_USE_LOCAL_ARRAYS
 347       PNG_CONST PNG_IHDR;
 348       PNG_CONST PNG_IDAT;
 349       PNG_CONST PNG_IEND;
 350       PNG_CONST PNG_PLTE;
 351 #if defined(PNG_READ_bKGD_SUPPORTED)
 352       PNG_CONST PNG_bKGD;
 353 #endif
 354 #if defined(PNG_READ_cHRM_SUPPORTED)
 355       PNG_CONST PNG_cHRM;
 356 #endif
 357 #if defined(PNG_READ_gAMA_SUPPORTED)
 358       PNG_CONST PNG_gAMA;
 359 #endif
 360 #if defined(PNG_READ_hIST_SUPPORTED)
 361       PNG_CONST PNG_hIST;
 362 #endif
 363 #if defined(PNG_READ_iCCP_SUPPORTED)
 364       PNG_CONST PNG_iCCP;
 365 #endif
 366 #if defined(PNG_READ_iTXt_SUPPORTED)
 367       PNG_CONST PNG_iTXt;
 368 #endif
 369 #if defined(PNG_READ_oFFs_SUPPORTED)
 370       PNG_CONST PNG_oFFs;
 371 #endif
 372 #if defined(PNG_READ_pCAL_SUPPORTED)
 373       PNG_CONST PNG_pCAL;
 374 #endif
 375 #if defined(PNG_READ_pHYs_SUPPORTED)
 376       PNG_CONST PNG_pHYs;
 377 #endif
 378 #if defined(PNG_READ_sBIT_SUPPORTED)
 379       PNG_CONST PNG_sBIT;
 380 #endif
 381 #if defined(PNG_READ_sCAL_SUPPORTED)
 382       PNG_CONST PNG_sCAL;
 383 #endif
 384 #if defined(PNG_READ_sPLT_SUPPORTED)
 385       PNG_CONST PNG_sPLT;
 386 #endif
 387 #if defined(PNG_READ_sRGB_SUPPORTED)
 388       PNG_CONST PNG_sRGB;
 389 #endif
 390 #if defined(PNG_READ_tEXt_SUPPORTED)
 391       PNG_CONST PNG_tEXt;
 392 #endif
 393 #if defined(PNG_READ_tIME_SUPPORTED)
 394       PNG_CONST PNG_tIME;
 395 #endif
 396 #if defined(PNG_READ_tRNS_SUPPORTED)
 397       PNG_CONST PNG_tRNS;
 398 #endif
 399 #if defined(PNG_READ_zTXt_SUPPORTED)
 400       PNG_CONST PNG_zTXt;
 401 #endif
 402 #endif /* PNG_USE_LOCAL_ARRAYS */
 403       png_byte chunk_length[4];
 404       png_uint_32 length;
 405
 406       png_read_data(png_ptr, chunk_length, 4);
 407       length = png_get_uint_31(png_ptr,chunk_length);
 408
 409       png_reset_crc(png_ptr);
 410       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 411
 412       png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
 413          length);
 414
 415       /* This should be a binary subdivision search or a hash for
 416        * matching the chunk name rather than a linear search.
 417        */
 418       if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
 419         if(png_ptr->mode & PNG_AFTER_IDAT)
 420           png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 421
 422       if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
 423          png_handle_IHDR(png_ptr, info_ptr, length);
 424       else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
 425          png_handle_IEND(png_ptr, info_ptr, length);
 426 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 427       else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
 428       {
 429          if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 430             png_ptr->mode |= PNG_HAVE_IDAT;
 431          png_handle_unknown(png_ptr, info_ptr, length);
 432          if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 433             png_ptr->mode |= PNG_HAVE_PLTE;
 434          else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 435          {
 436             if (!(png_ptr->mode & PNG_HAVE_IHDR))
 437                png_error(png_ptr, "Missing IHDR before IDAT");
 438             else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 439                      !(png_ptr->mode & PNG_HAVE_PLTE))
 440                png_error(png_ptr, "Missing PLTE before IDAT");
 441             break;
 442          }
 443       }
 444 #endif
 445       else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 446          png_handle_PLTE(png_ptr, info_ptr, length);
 447       else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 448       {
 449          if (!(png_ptr->mode & PNG_HAVE_IHDR))
 450             png_error(png_ptr, "Missing IHDR before IDAT");
 451          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 452                   !(png_ptr->mode & PNG_HAVE_PLTE))
 453             png_error(png_ptr, "Missing PLTE before IDAT");
 454
 455          png_ptr->idat_size = length;
 456          png_ptr->mode |= PNG_HAVE_IDAT;
 457          break;
 458       }
 459 #if defined(PNG_READ_bKGD_SUPPORTED)
 460       else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
 461          png_handle_bKGD(png_ptr, info_ptr, length);
 462 #endif
 463 #if defined(PNG_READ_cHRM_SUPPORTED)
 464       else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
 465          png_handle_cHRM(png_ptr, info_ptr, length);
 466 #endif
 467 #if defined(PNG_READ_gAMA_SUPPORTED)
 468       else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
 469          png_handle_gAMA(png_ptr, info_ptr, length);
 470 #endif
 471 #if defined(PNG_READ_hIST_SUPPORTED)
 472       else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
 473          png_handle_hIST(png_ptr, info_ptr, length);
 474 #endif
 475 #if defined(PNG_READ_oFFs_SUPPORTED)
 476       else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
 477          png_handle_oFFs(png_ptr, info_ptr, length);
 478 #endif
 479 #if defined(PNG_READ_pCAL_SUPPORTED)
 480       else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
 481          png_handle_pCAL(png_ptr, info_ptr, length);
 482 #endif
 483 #if defined(PNG_READ_sCAL_SUPPORTED)
 484       else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
 485          png_handle_sCAL(png_ptr, info_ptr, length);
 486 #endif
 487 #if defined(PNG_READ_pHYs_SUPPORTED)
 488       else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
 489          png_handle_pHYs(png_ptr, info_ptr, length);
 490 #endif
 491 #if defined(PNG_READ_sBIT_SUPPORTED)
 492       else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
 493          png_handle_sBIT(png_ptr, info_ptr, length);
 494 #endif
 495 #if defined(PNG_READ_sRGB_SUPPORTED)
 496       else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
 497          png_handle_sRGB(png_ptr, info_ptr, length);
 498 #endif
 499 #if defined(PNG_READ_iCCP_SUPPORTED)
 500       else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
 501          png_handle_iCCP(png_ptr, info_ptr, length);
 502 #endif
 503 #if defined(PNG_READ_sPLT_SUPPORTED)
 504       else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
 505          png_handle_sPLT(png_ptr, info_ptr, length);
 506 #endif
 507 #if defined(PNG_READ_tEXt_SUPPORTED)
 508       else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
 509          png_handle_tEXt(png_ptr, info_ptr, length);
 510 #endif
 511 #if defined(PNG_READ_tIME_SUPPORTED)
 512       else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
 513          png_handle_tIME(png_ptr, info_ptr, length);
 514 #endif
 515 #if defined(PNG_READ_tRNS_SUPPORTED)
 516       else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
 517          png_handle_tRNS(png_ptr, info_ptr, length);
 518 #endif
 519 #if defined(PNG_READ_zTXt_SUPPORTED)
 520       else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
 521          png_handle_zTXt(png_ptr, info_ptr, length);
 522 #endif
 523 #if defined(PNG_READ_iTXt_SUPPORTED)
 524       else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
 525          png_handle_iTXt(png_ptr, info_ptr, length);
 526 #endif
 527       else
 528          png_handle_unknown(png_ptr, info_ptr, length);
 529    }
 530 }
 531 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 532
 533 /* optional call to update the users info_ptr structure */
 534 void PNGAPI
 535 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 536 {
 537    png_debug(1, "in png_read_update_info\n");
 538    if(png_ptr == NULL) return;
 539    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 540       png_read_start_row(png_ptr);
 541    else
 542       png_warning(png_ptr,
 543       "Ignoring extra png_read_update_info() call; row buffer not reallocated");
 544    png_read_transform_info(png_ptr, info_ptr);
 545 }
 546
 547 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 548 /* Initialize palette, background, etc, after transformations
 549  * are set, but before any reading takes place.  This allows
 550  * the user to obtain a gamma-corrected palette, for example.
 551  * If the user doesn't call this, we will do it ourselves.
 552  */
 553 void PNGAPI
 554 png_start_read_image(png_structp png_ptr)
 555 {
 556    png_debug(1, "in png_start_read_image\n");
 557    if(png_ptr == NULL) return;
 558    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 559       png_read_start_row(png_ptr);
 560 }
 561 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 562
 563 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 564 void PNGAPI
 565 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 566 {
 567 #ifdef PNG_USE_LOCAL_ARRAYS
 568    PNG_CONST PNG_IDAT;
 569    PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
 570      0xff};
 571    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 572 #endif
 573    int ret;
 574    if(png_ptr == NULL) return;
 575    png_debug2(1, "in png_read_row (row %lu, pass %d)\n",
 576       png_ptr->row_number, png_ptr->pass);
 577    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
 578       png_read_start_row(png_ptr);
 579    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
 580    {
 581    /* check for transforms that have been set but were defined out */
 582 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
 583    if (png_ptr->transformations & PNG_INVERT_MONO)
 584       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
 585 #endif
 586 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
 587    if (png_ptr->transformations & PNG_FILLER)
 588       png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
 589 #endif
 590 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
 591    if (png_ptr->transformations & PNG_PACKSWAP)
 592       png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
 593 #endif
 594 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
 595    if (png_ptr->transformations & PNG_PACK)
 596       png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
 597 #endif
 598 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
 599    if (png_ptr->transformations & PNG_SHIFT)
 600       png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
 601 #endif
 602 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
 603    if (png_ptr->transformations & PNG_BGR)
 604       png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
 605 #endif
 606 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
 607    if (png_ptr->transformations & PNG_SWAP_BYTES)
 608       png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
 609 #endif
 610    }
 611
 612 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 613    /* if interlaced and we do not need a new row, combine row and return */
 614    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 615    {
 616       switch (png_ptr->pass)
 617       {
 618          case 0:
 619             if (png_ptr->row_number & 0x07)
 620             {
 621                if (dsp_row != NULL)
 622                   png_combine_row(png_ptr, dsp_row,
 623                      png_pass_dsp_mask[png_ptr->pass]);
 624                png_read_finish_row(png_ptr);
 625                return;
 626             }
 627             break;
 628          case 1:
 629             if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
 630             {
 631                if (dsp_row != NULL)
 632                   png_combine_row(png_ptr, dsp_row,
 633                      png_pass_dsp_mask[png_ptr->pass]);
 634                png_read_finish_row(png_ptr);
 635                return;
 636             }
 637             break;
 638          case 2:
 639             if ((png_ptr->row_number & 0x07) != 4)
 640             {
 641                if (dsp_row != NULL && (png_ptr->row_number & 4))
 642                   png_combine_row(png_ptr, dsp_row,
 643                      png_pass_dsp_mask[png_ptr->pass]);
 644                png_read_finish_row(png_ptr);
 645                return;
 646             }
 647             break;
 648          case 3:
 649             if ((png_ptr->row_number & 3) || png_ptr->width < 3)
 650             {
 651                if (dsp_row != NULL)
 652                   png_combine_row(png_ptr, dsp_row,
 653                      png_pass_dsp_mask[png_ptr->pass]);
 654                png_read_finish_row(png_ptr);
 655                return;
 656             }
 657             break;
 658          case 4:
 659             if ((png_ptr->row_number & 3) != 2)
 660             {
 661                if (dsp_row != NULL && (png_ptr->row_number & 2))
 662                   png_combine_row(png_ptr, dsp_row,
 663                      png_pass_dsp_mask[png_ptr->pass]);
 664                png_read_finish_row(png_ptr);
 665                return;
 666             }
 667             break;
 668          case 5:
 669             if ((png_ptr->row_number & 1) || png_ptr->width < 2)
 670             {
 671                if (dsp_row != NULL)
 672                   png_combine_row(png_ptr, dsp_row,
 673                      png_pass_dsp_mask[png_ptr->pass]);
 674                png_read_finish_row(png_ptr);
 675                return;
 676             }
 677             break;
 678          case 6:
 679             if (!(png_ptr->row_number & 1))
 680             {
 681                png_read_finish_row(png_ptr);
 682                return;
 683             }
 684             break;
 685       }
 686    }
 687 #endif
 688
 689    if (!(png_ptr->mode & PNG_HAVE_IDAT))
 690       png_error(png_ptr, "Invalid attempt to read row data");
 691
 692    png_ptr->zstream.next_out = png_ptr->row_buf;
 693    png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
 694    do
 695    {
 696       if (!(png_ptr->zstream.avail_in))
 697       {
 698          while (!png_ptr->idat_size)
 699          {
 700             png_byte chunk_length[4];
 701
 702             png_crc_finish(png_ptr, 0);
 703
 704             png_read_data(png_ptr, chunk_length, 4);
 705             png_ptr->idat_size = png_get_uint_31(png_ptr,chunk_length);
 706
 707             png_reset_crc(png_ptr);
 708             png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 709             if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 710                png_error(png_ptr, "Not enough image data");
 711          }
 712          png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
 713          png_ptr->zstream.next_in = png_ptr->zbuf;
 714          if (png_ptr->zbuf_size > png_ptr->idat_size)
 715             png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
 716          png_crc_read(png_ptr, png_ptr->zbuf,
 717             (png_size_t)png_ptr->zstream.avail_in);
 718          png_ptr->idat_size -= png_ptr->zstream.avail_in;
 719       }
 720       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 721       if (ret == Z_STREAM_END)
 722       {
 723          if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
 724             png_ptr->idat_size)
 725             png_error(png_ptr, "Extra compressed data");
 726          png_ptr->mode |= PNG_AFTER_IDAT;
 727          png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 728          break;
 729       }
 730       if (ret != Z_OK)
 731          png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
 732                    "Decompression error");
 733
 734    } while (png_ptr->zstream.avail_out);
 735
 736    png_ptr->row_info.color_type = png_ptr->color_type;
 737    png_ptr->row_info.width = png_ptr->iwidth;
 738    png_ptr->row_info.channels = png_ptr->channels;
 739    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 740    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 741    png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
 742        png_ptr->row_info.width);
 743
 744    if(png_ptr->row_buf[0])
 745    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 746       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 747       (int)(png_ptr->row_buf[0]));
 748
 749    png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
 750       png_ptr->rowbytes + 1);
 751
 752 #if defined(PNG_MNG_FEATURES_SUPPORTED)
 753    if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
 754       (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
 755    {
 756       /* Intrapixel differencing */
 757       png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
 758    }
 759 #endif
 760
 761
 762    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
 763       png_do_read_transformations(png_ptr);
 764
 765 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 766    /* blow up interlaced rows to full size */
 767    if (png_ptr->interlaced &&
 768       (png_ptr->transformations & PNG_INTERLACE))
 769    {
 770       if (png_ptr->pass < 6)
 771 /*       old interface (pre-1.0.9):
 772          png_do_read_interlace(&(png_ptr->row_info),
 773             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 774  */
 775          png_do_read_interlace(png_ptr);
 776
 777       if (dsp_row != NULL)
 778          png_combine_row(png_ptr, dsp_row,
 779             png_pass_dsp_mask[png_ptr->pass]);
 780       if (row != NULL)
 781          png_combine_row(png_ptr, row,
 782             png_pass_mask[png_ptr->pass]);
 783    }
 784    else
 785 #endif
 786    {
 787       if (row != NULL)
 788          png_combine_row(png_ptr, row, 0xff);
 789       if (dsp_row != NULL)
 790          png_combine_row(png_ptr, dsp_row, 0xff);
 791    }
 792    png_read_finish_row(png_ptr);
 793
 794    if (png_ptr->read_row_fn != NULL)
 795       (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
 796 }
 797 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 798
 799 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 800 /* Read one or more rows of image data.  If the image is interlaced,
 801  * and png_set_interlace_handling() has been called, the rows need to
 802  * contain the contents of the rows from the previous pass.  If the
 803  * image has alpha or transparency, and png_handle_alpha()[*] has been
 804  * called, the rows contents must be initialized to the contents of the
 805  * screen.
 806  *
 807  * "row" holds the actual image, and pixels are placed in it
 808  * as they arrive.  If the image is displayed after each pass, it will
 809  * appear to "sparkle" in.  "display_row" can be used to display a
 810  * "chunky" progressive image, with finer detail added as it becomes
 811  * available.  If you do not want this "chunky" display, you may pass
 812  * NULL for display_row.  If you do not want the sparkle display, and
 813  * you have not called png_handle_alpha(), you may pass NULL for rows.
 814  * If you have called png_handle_alpha(), and the image has either an
 815  * alpha channel or a transparency chunk, you must provide a buffer for
 816  * rows.  In this case, you do not have to provide a display_row buffer
 817  * also, but you may.  If the image is not interlaced, or if you have
 818  * not called png_set_interlace_handling(), the display_row buffer will
 819  * be ignored, so pass NULL to it.
 820  *
 821  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 822  */
 823
 824 void PNGAPI
 825 png_read_rows(png_structp png_ptr, png_bytepp row,
 826    png_bytepp display_row, png_uint_32 num_rows)
 827 {
 828    png_uint_32 i;
 829    png_bytepp rp;
 830    png_bytepp dp;
 831
 832    png_debug(1, "in png_read_rows\n");
 833    if(png_ptr == NULL) return;
 834    rp = row;
 835    dp = display_row;
 836    if (rp != NULL && dp != NULL)
 837       for (i = 0; i < num_rows; i++)
 838       {
 839          png_bytep rptr = *rp++;
 840          png_bytep dptr = *dp++;
 841
 842          png_read_row(png_ptr, rptr, dptr);
 843       }
 844    else if(rp != NULL)
 845       for (i = 0; i < num_rows; i++)
 846       {
 847          png_bytep rptr = *rp;
 848          png_read_row(png_ptr, rptr, png_bytep_NULL);
 849          rp++;
 850       }
 851    else if(dp != NULL)
 852       for (i = 0; i < num_rows; i++)
 853       {
 854          png_bytep dptr = *dp;
 855          png_read_row(png_ptr, png_bytep_NULL, dptr);
 856          dp++;
 857       }
 858 }
 859 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 860
 861 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 862 /* Read the entire image.  If the image has an alpha channel or a tRNS
 863  * chunk, and you have called png_handle_alpha()[*], you will need to
 864  * initialize the image to the current image that PNG will be overlaying.
 865  * We set the num_rows again here, in case it was incorrectly set in
 866  * png_read_start_row() by a call to png_read_update_info() or
 867  * png_start_read_image() if png_set_interlace_handling() wasn't called
 868  * prior to either of these functions like it should have been.  You can
 869  * only call this function once.  If you desire to have an image for
 870  * each pass of a interlaced image, use png_read_rows() instead.
 871  *
 872  * [*] png_handle_alpha() does not exist yet, as of this version of libpng
 873  */
 874 void PNGAPI
 875 png_read_image(png_structp png_ptr, png_bytepp image)
 876 {
 877    png_uint_32 i,image_height;
 878    int pass, j;
 879    png_bytepp rp;
 880
 881    png_debug(1, "in png_read_image\n");
 882    if(png_ptr == NULL) return;
 883
 884 #ifdef PNG_READ_INTERLACING_SUPPORTED
 885    pass = png_set_interlace_handling(png_ptr);
 886 #else
 887    if (png_ptr->interlaced)
 888       png_error(png_ptr,
 889         "Cannot read interlaced image -- interlace handler disabled.");
 890    pass = 1;
 891 #endif
 892
 893
 894    image_height=png_ptr->height;
 895    png_ptr->num_rows = image_height; /* Make sure this is set correctly */
 896
 897    for (j = 0; j < pass; j++)
 898    {
 899       rp = image;
 900       for (i = 0; i < image_height; i++)
 901       {
 902          png_read_row(png_ptr, *rp, png_bytep_NULL);
 903          rp++;
 904       }
 905    }
 906 }
 907 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 908
 909 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
 910 /* Read the end of the PNG file.  Will not read past the end of the
 911  * file, will verify the end is accurate, and will read any comments
 912  * or time information at the end of the file, if info is not NULL.
 913  */
 914 void PNGAPI
 915 png_read_end(png_structp png_ptr, png_infop info_ptr)
 916 {
 917    png_byte chunk_length[4];
 918    png_uint_32 length;
 919
 920    png_debug(1, "in png_read_end\n");
 921    if(png_ptr == NULL) return;
 922    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 923
 924    do
 925    {
 926 #ifdef PNG_USE_LOCAL_ARRAYS
 927       PNG_CONST PNG_IHDR;
 928       PNG_CONST PNG_IDAT;
 929       PNG_CONST PNG_IEND;
 930       PNG_CONST PNG_PLTE;
 931 #if defined(PNG_READ_bKGD_SUPPORTED)
 932       PNG_CONST PNG_bKGD;
 933 #endif
 934 #if defined(PNG_READ_cHRM_SUPPORTED)
 935       PNG_CONST PNG_cHRM;
 936 #endif
 937 #if defined(PNG_READ_gAMA_SUPPORTED)
 938       PNG_CONST PNG_gAMA;
 939 #endif
 940 #if defined(PNG_READ_hIST_SUPPORTED)
 941       PNG_CONST PNG_hIST;
 942 #endif
 943 #if defined(PNG_READ_iCCP_SUPPORTED)
 944       PNG_CONST PNG_iCCP;
 945 #endif
 946 #if defined(PNG_READ_iTXt_SUPPORTED)
 947       PNG_CONST PNG_iTXt;
 948 #endif
 949 #if defined(PNG_READ_oFFs_SUPPORTED)
 950       PNG_CONST PNG_oFFs;
 951 #endif
 952 #if defined(PNG_READ_pCAL_SUPPORTED)
 953       PNG_CONST PNG_pCAL;
 954 #endif
 955 #if defined(PNG_READ_pHYs_SUPPORTED)
 956       PNG_CONST PNG_pHYs;
 957 #endif
 958 #if defined(PNG_READ_sBIT_SUPPORTED)
 959       PNG_CONST PNG_sBIT;
 960 #endif
 961 #if defined(PNG_READ_sCAL_SUPPORTED)
 962       PNG_CONST PNG_sCAL;
 963 #endif
 964 #if defined(PNG_READ_sPLT_SUPPORTED)
 965       PNG_CONST PNG_sPLT;
 966 #endif
 967 #if defined(PNG_READ_sRGB_SUPPORTED)
 968       PNG_CONST PNG_sRGB;
 969 #endif
 970 #if defined(PNG_READ_tEXt_SUPPORTED)
 971       PNG_CONST PNG_tEXt;
 972 #endif
 973 #if defined(PNG_READ_tIME_SUPPORTED)
 974       PNG_CONST PNG_tIME;
 975 #endif
 976 #if defined(PNG_READ_tRNS_SUPPORTED)
 977       PNG_CONST PNG_tRNS;
 978 #endif
 979 #if defined(PNG_READ_zTXt_SUPPORTED)
 980       PNG_CONST PNG_zTXt;
 981 #endif
 982 #endif /* PNG_USE_LOCAL_ARRAYS */
 983
 984       png_read_data(png_ptr, chunk_length, 4);
 985       length = png_get_uint_31(png_ptr,chunk_length);
 986
 987       png_reset_crc(png_ptr);
 988       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 989
 990       png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);
 991
 992       if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
 993          png_handle_IHDR(png_ptr, info_ptr, length);
 994       else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
 995          png_handle_IEND(png_ptr, info_ptr, length);
 996 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 997       else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
 998       {
 999          if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
1000          {
1001             if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
1002                png_error(png_ptr, "Too many IDAT's found");
1003          }
1004          png_handle_unknown(png_ptr, info_ptr, length);
1005          if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
1006             png_ptr->mode |= PNG_HAVE_PLTE;
1007       }
1008 #endif
1009       else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
1010       {
1011          /* Zero length IDATs are legal after the last IDAT has been
1012           * read, but not after other chunks have been read.
1013           */
1014          if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
1015             png_error(png_ptr, "Too many IDAT's found");
1016          png_crc_finish(png_ptr, length);
1017       }
1018       else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
1019          png_handle_PLTE(png_ptr, info_ptr, length);
1020 #if defined(PNG_READ_bKGD_SUPPORTED)
1021       else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
1022          png_handle_bKGD(png_ptr, info_ptr, length);
1023 #endif
1024 #if defined(PNG_READ_cHRM_SUPPORTED)
1025       else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
1026          png_handle_cHRM(png_ptr, info_ptr, length);
1027 #endif
1028 #if defined(PNG_READ_gAMA_SUPPORTED)
1029       else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
1030          png_handle_gAMA(png_ptr, info_ptr, length);
1031 #endif
1032 #if defined(PNG_READ_hIST_SUPPORTED)
1033       else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
1034          png_handle_hIST(png_ptr, info_ptr, length);
1035 #endif
1036 #if defined(PNG_READ_oFFs_SUPPORTED)
1037       else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
1038          png_handle_oFFs(png_ptr, info_ptr, length);
1039 #endif
1040 #if defined(PNG_READ_pCAL_SUPPORTED)
1041       else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
1042          png_handle_pCAL(png_ptr, info_ptr, length);
1043 #endif
1044 #if defined(PNG_READ_sCAL_SUPPORTED)
1045       else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
1046          png_handle_sCAL(png_ptr, info_ptr, length);
1047 #endif
1048 #if defined(PNG_READ_pHYs_SUPPORTED)
1049       else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
1050          png_handle_pHYs(png_ptr, info_ptr, length);
1051 #endif
1052 #if defined(PNG_READ_sBIT_SUPPORTED)
1053       else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
1054          png_handle_sBIT(png_ptr, info_ptr, length);
1055 #endif
1056 #if defined(PNG_READ_sRGB_SUPPORTED)
1057       else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
1058          png_handle_sRGB(png_ptr, info_ptr, length);
1059 #endif
1060 #if defined(PNG_READ_iCCP_SUPPORTED)
1061       else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
1062          png_handle_iCCP(png_ptr, info_ptr, length);
1063 #endif
1064 #if defined(PNG_READ_sPLT_SUPPORTED)
1065       else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
1066          png_handle_sPLT(png_ptr, info_ptr, length);
1067 #endif
1068 #if defined(PNG_READ_tEXt_SUPPORTED)
1069       else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
1070          png_handle_tEXt(png_ptr, info_ptr, length);
1071 #endif
1072 #if defined(PNG_READ_tIME_SUPPORTED)
1073       else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
1074          png_handle_tIME(png_ptr, info_ptr, length);
1075 #endif
1076 #if defined(PNG_READ_tRNS_SUPPORTED)
1077       else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
1078          png_handle_tRNS(png_ptr, info_ptr, length);
1079 #endif
1080 #if defined(PNG_READ_zTXt_SUPPORTED)
1081       else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
1082          png_handle_zTXt(png_ptr, info_ptr, length);
1083 #endif
1084 #if defined(PNG_READ_iTXt_SUPPORTED)
1085       else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
1086          png_handle_iTXt(png_ptr, info_ptr, length);
1087 #endif
1088       else
1089          png_handle_unknown(png_ptr, info_ptr, length);
1090    } while (!(png_ptr->mode & PNG_HAVE_IEND));
1091 }
1092 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
1093
1094 /* free all memory used by the read */
1095 void PNGAPI
1096 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
1097    png_infopp end_info_ptr_ptr)
1098 {
1099    png_structp png_ptr = NULL;
1100    png_infop info_ptr = NULL, end_info_ptr = NULL;
1101 #ifdef PNG_USER_MEM_SUPPORTED
1102    png_free_ptr free_fn;
1103    png_voidp mem_ptr;
1104 #endif
1105
1106    png_debug(1, "in png_destroy_read_struct\n");
1107    if (png_ptr_ptr != NULL)
1108       png_ptr = *png_ptr_ptr;
1109
1110    if (info_ptr_ptr != NULL)
1111       info_ptr = *info_ptr_ptr;
1112
1113    if (end_info_ptr_ptr != NULL)
1114       end_info_ptr = *end_info_ptr_ptr;
1115
1116 #ifdef PNG_USER_MEM_SUPPORTED
1117    free_fn = png_ptr->free_fn;
1118    mem_ptr = png_ptr->mem_ptr;
1119 #endif
1120
1121    png_read_destroy(png_ptr, info_ptr, end_info_ptr);
1122
1123    if (info_ptr != NULL)
1124    {
1125 #if defined(PNG_TEXT_SUPPORTED)
1126       png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
1127 #endif
1128
1129 #ifdef PNG_USER_MEM_SUPPORTED
1130       png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1131           (png_voidp)mem_ptr);
1132 #else
1133       png_destroy_struct((png_voidp)info_ptr);
1134 #endif
1135       *info_ptr_ptr = NULL;
1136    }
1137
1138    if (end_info_ptr != NULL)
1139    {
1140 #if defined(PNG_READ_TEXT_SUPPORTED)
1141       png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
1142 #endif
1143 #ifdef PNG_USER_MEM_SUPPORTED
1144       png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
1145          (png_voidp)mem_ptr);
1146 #else
1147       png_destroy_struct((png_voidp)end_info_ptr);
1148 #endif
1149       *end_info_ptr_ptr = NULL;
1150    }
1151
1152    if (png_ptr != NULL)
1153    {
1154 #ifdef PNG_USER_MEM_SUPPORTED
1155       png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1156           (png_voidp)mem_ptr);
1157 #else
1158       png_destroy_struct((png_voidp)png_ptr);
1159 #endif
1160       *png_ptr_ptr = NULL;
1161    }
1162 }
1163
1164 /* free all memory used by the read (old method) */
1165 void /* PRIVATE */
1166 png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
1167 {
1168 #ifdef PNG_SETJMP_SUPPORTED
1169    jmp_buf tmp_jmp;
1170 #endif
1171    png_error_ptr error_fn;
1172    png_error_ptr warning_fn;
1173    png_voidp error_ptr;
1174 #ifdef PNG_USER_MEM_SUPPORTED
1175    png_free_ptr free_fn;
1176 #endif
1177
1178    png_debug(1, "in png_read_destroy\n");
1179    if (info_ptr != NULL)
1180       png_info_destroy(png_ptr, info_ptr);
1181
1182    if (end_info_ptr != NULL)
1183       png_info_destroy(png_ptr, end_info_ptr);
1184
1185    png_free(png_ptr, png_ptr->zbuf);
1186    png_free(png_ptr, png_ptr->big_row_buf);
1187    png_free(png_ptr, png_ptr->prev_row);
1188 #if defined(PNG_READ_DITHER_SUPPORTED)
1189    png_free(png_ptr, png_ptr->palette_lookup);
1190    png_free(png_ptr, png_ptr->dither_index);
1191 #endif
1192 #if defined(PNG_READ_GAMMA_SUPPORTED)
1193    png_free(png_ptr, png_ptr->gamma_table);
1194 #endif
1195 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
1196    png_free(png_ptr, png_ptr->gamma_from_1);
1197    png_free(png_ptr, png_ptr->gamma_to_1);
1198 #endif
1199 #ifdef PNG_FREE_ME_SUPPORTED
1200    if (png_ptr->free_me & PNG_FREE_PLTE)
1201       png_zfree(png_ptr, png_ptr->palette);
1202    png_ptr->free_me &= ~PNG_FREE_PLTE;
1203 #else
1204    if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
1205       png_zfree(png_ptr, png_ptr->palette);
1206    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
1207 #endif
1208 #if defined(PNG_tRNS_SUPPORTED) || \
1209     defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
1210 #ifdef PNG_FREE_ME_SUPPORTED
1211    if (png_ptr->free_me & PNG_FREE_TRNS)
1212       png_free(png_ptr, png_ptr->trans);
1213    png_ptr->free_me &= ~PNG_FREE_TRNS;
1214 #else
1215    if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
1216       png_free(png_ptr, png_ptr->trans);
1217    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
1218 #endif
1219 #endif
1220 #if defined(PNG_READ_hIST_SUPPORTED)
1221 #ifdef PNG_FREE_ME_SUPPORTED
1222    if (png_ptr->free_me & PNG_FREE_HIST)
1223       png_free(png_ptr, png_ptr->hist);
1224    png_ptr->free_me &= ~PNG_FREE_HIST;
1225 #else
1226    if (png_ptr->flags & PNG_FLAG_FREE_HIST)
1227       png_free(png_ptr, png_ptr->hist);
1228    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
1229 #endif
1230 #endif
1231 #if defined(PNG_READ_GAMMA_SUPPORTED)
1232    if (png_ptr->gamma_16_table != NULL)
1233    {
1234       int i;
1235       int istop = (1 << (8 - png_ptr->gamma_shift));
1236       for (i = 0; i < istop; i++)
1237       {
1238          png_free(png_ptr, png_ptr->gamma_16_table[i]);
1239       }
1240    png_free(png_ptr, png_ptr->gamma_16_table);
1241    }
1242 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
1243    if (png_ptr->gamma_16_from_1 != NULL)
1244    {
1245       int i;
1246       int istop = (1 << (8 - png_ptr->gamma_shift));
1247       for (i = 0; i < istop; i++)
1248       {
1249          png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
1250       }
1251    png_free(png_ptr, png_ptr->gamma_16_from_1);
1252    }
1253    if (png_ptr->gamma_16_to_1 != NULL)
1254    {
1255       int i;
1256       int istop = (1 << (8 - png_ptr->gamma_shift));
1257       for (i = 0; i < istop; i++)
1258       {
1259          png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
1260       }
1261    png_free(png_ptr, png_ptr->gamma_16_to_1);
1262    }
1263 #endif
1264 #endif
1265 #if defined(PNG_TIME_RFC1123_SUPPORTED)
1266    png_free(png_ptr, png_ptr->time_buffer);
1267 #endif
1268
1269    inflateEnd(&png_ptr->zstream);
1270 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1271    png_free(png_ptr, png_ptr->save_buffer);
1272 #endif
1273
1274 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1275 #ifdef PNG_TEXT_SUPPORTED
1276    png_free(png_ptr, png_ptr->current_text);
1277 #endif /* PNG_TEXT_SUPPORTED */
1278 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1279
1280    /* Save the important info out of the png_struct, in case it is
1281     * being used again.
1282     */
1283 #ifdef PNG_SETJMP_SUPPORTED
1284    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
1285 #endif
1286
1287    error_fn = png_ptr->error_fn;
1288    warning_fn = png_ptr->warning_fn;
1289    error_ptr = png_ptr->error_ptr;
1290 #ifdef PNG_USER_MEM_SUPPORTED
1291    free_fn = png_ptr->free_fn;
1292 #endif
1293
1294    png_memset(png_ptr, 0, png_sizeof (png_struct));
1295
1296    png_ptr->error_fn = error_fn;
1297    png_ptr->warning_fn = warning_fn;
1298    png_ptr->error_ptr = error_ptr;
1299 #ifdef PNG_USER_MEM_SUPPORTED
1300    png_ptr->free_fn = free_fn;
1301 #endif
1302
1303 #ifdef PNG_SETJMP_SUPPORTED
1304    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
1305 #endif
1306
1307 }
1308
1309 void PNGAPI
1310 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
1311 {
1312    if(png_ptr == NULL) return;
1313    png_ptr->read_row_fn = read_row_fn;
1314 }
1315
1316
1317 #ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
1318 #if defined(PNG_INFO_IMAGE_SUPPORTED)
1319 void PNGAPI
1320 png_read_png(png_structp png_ptr, png_infop info_ptr,
1321                            int transforms,
1322                            voidp params)
1323 {
1324    int row;
1325
1326    if(png_ptr == NULL) return;
1327 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
1328    /* invert the alpha channel from opacity to transparency
1329     */
1330    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1331        png_set_invert_alpha(png_ptr);
1332 #endif
1333
1334    /* png_read_info() gives us all of the information from the
1335     * PNG file before the first IDAT (image data chunk).
1336     */
1337    png_read_info(png_ptr, info_ptr);
1338    if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
1339       png_error(png_ptr,"Image is too high to process with png_read_png()");
1340
1341    /* -------------- image transformations start here ------------------- */
1342
1343 #if defined(PNG_READ_16_TO_8_SUPPORTED)
1344    /* tell libpng to strip 16 bit/color files down to 8 bits per color
1345     */
1346    if (transforms & PNG_TRANSFORM_STRIP_16)
1347        png_set_strip_16(png_ptr);
1348 #endif
1349
1350 #if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
1351    /* Strip alpha bytes from the input data without combining with
1352     * the background (not recommended).
1353     */
1354    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
1355        png_set_strip_alpha(png_ptr);
1356 #endif
1357
1358 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
1359    /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
1360     * byte into separate bytes (useful for paletted and grayscale images).
1361     */
1362    if (transforms & PNG_TRANSFORM_PACKING)
1363        png_set_packing(png_ptr);
1364 #endif
1365
1366 #if defined(PNG_READ_PACKSWAP_SUPPORTED)
1367    /* Change the order of packed pixels to least significant bit first
1368     * (not useful if you are using png_set_packing).
1369     */
1370    if (transforms & PNG_TRANSFORM_PACKSWAP)
1371        png_set_packswap(png_ptr);
1372 #endif
1373
1374 #if defined(PNG_READ_EXPAND_SUPPORTED)
1375    /* Expand paletted colors into true RGB triplets
1376     * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
1377     * Expand paletted or RGB images with transparency to full alpha
1378     * channels so the data will be available as RGBA quartets.
1379     */
1380    if (transforms & PNG_TRANSFORM_EXPAND)
1381        if ((png_ptr->bit_depth < 8) ||
1382            (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
1383            (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
1384          png_set_expand(png_ptr);
1385 #endif
1386
1387    /* We don't handle background color or gamma transformation or dithering.
1388     */
1389
1390 #if defined(PNG_READ_INVERT_SUPPORTED)
1391    /* invert monochrome files to have 0 as white and 1 as black
1392     */
1393    if (transforms & PNG_TRANSFORM_INVERT_MONO)
1394        png_set_invert_mono(png_ptr);
1395 #endif
1396
1397 #if defined(PNG_READ_SHIFT_SUPPORTED)
1398    /* If you want to shift the pixel values from the range [0,255] or
1399     * [0,65535] to the original [0,7] or [0,31], or whatever range the
1400     * colors were originally in:
1401     */
1402    if ((transforms & PNG_TRANSFORM_SHIFT)
1403        && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
1404    {
1405       png_color_8p sig_bit;
1406
1407       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
1408       png_set_shift(png_ptr, sig_bit);
1409    }
1410 #endif
1411
1412 #if defined(PNG_READ_BGR_SUPPORTED)
1413    /* flip the RGB pixels to BGR (or RGBA to BGRA)
1414     */
1415    if (transforms & PNG_TRANSFORM_BGR)
1416        png_set_bgr(png_ptr);
1417 #endif
1418
1419 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
1420    /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
1421     */
1422    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1423        png_set_swap_alpha(png_ptr);
1424 #endif
1425
1426 #if defined(PNG_READ_SWAP_SUPPORTED)
1427    /* swap bytes of 16 bit files to least significant byte first
1428     */
1429    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1430        png_set_swap(png_ptr);
1431 #endif
1432
1433    /* We don't handle adding filler bytes */
1434
1435    /* Optional call to gamma correct and add the background to the palette
1436     * and update info structure.  REQUIRED if you are expecting libpng to
1437     * update the palette for you (i.e., you selected such a transform above).
1438     */
1439    png_read_update_info(png_ptr, info_ptr);
1440
1441    /* -------------- image transformations end here ------------------- */
1442
1443 #ifdef PNG_FREE_ME_SUPPORTED
1444    png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
1445 #endif
1446    if(info_ptr->row_pointers == NULL)
1447    {
1448       info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
1449          info_ptr->height * png_sizeof(png_bytep));
1450 #ifdef PNG_FREE_ME_SUPPORTED
1451       info_ptr->free_me |= PNG_FREE_ROWS;
1452 #endif
1453       for (row = 0; row < (int)info_ptr->height; row++)
1454       {
1455          info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
1456             png_get_rowbytes(png_ptr, info_ptr));
1457       }
1458    }
1459
1460    png_read_image(png_ptr, info_ptr->row_pointers);
1461    info_ptr->valid |= PNG_INFO_IDAT;
1462
1463    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
1464    png_read_end(png_ptr, info_ptr);
1465
1466    transforms = transforms; /* quiet compiler warnings */
1467    params = params;
1468
1469 }
1470 #endif /* PNG_INFO_IMAGE_SUPPORTED */
1471 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
1472 #endif /* PNG_READ_SUPPORTED */