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/src/compiler/android/jni/ftk/pngpread.c

http://ftk.googlecode.com/
C | 1774 lines | 1398 code | 278 blank | 98 comment | 325 complexity | 2ee0cf85f96c50c53463d7a1ec3b5e75 MD5 | raw file
   1
   2/* pngpread.c - read a png file in push mode
   3 *
   4 * Last changed in libpng 1.2.44 [June 26, 2010]
   5 * Copyright (c) 1998-2010 Glenn Randers-Pehrson
   6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   8 *
   9 * This code is released under the libpng license.
  10 * For conditions of distribution and use, see the disclaimer
  11 * and license in png.h
  12 */
  13
  14#define PNG_INTERNAL
  15#define PNG_NO_PEDANTIC_WARNINGS
  16#include "png.h"
  17#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
  18
  19/* Push model modes */
  20#define PNG_READ_SIG_MODE   0
  21#define PNG_READ_CHUNK_MODE 1
  22#define PNG_READ_IDAT_MODE  2
  23#define PNG_SKIP_MODE       3
  24#define PNG_READ_tEXt_MODE  4
  25#define PNG_READ_zTXt_MODE  5
  26#define PNG_READ_DONE_MODE  6
  27#define PNG_READ_iTXt_MODE  7
  28#define PNG_ERROR_MODE      8
  29
  30void PNGAPI
  31png_process_data(png_structp png_ptr, png_infop info_ptr,
  32   png_bytep buffer, png_size_t buffer_size)
  33{
  34   if (png_ptr == NULL || info_ptr == NULL)
  35      return;
  36
  37   png_push_restore_buffer(png_ptr, buffer, buffer_size);
  38
  39   while (png_ptr->buffer_size)
  40   {
  41      png_process_some_data(png_ptr, info_ptr);
  42   }
  43}
  44
  45/* What we do with the incoming data depends on what we were previously
  46 * doing before we ran out of data...
  47 */
  48void /* PRIVATE */
  49png_process_some_data(png_structp png_ptr, png_infop info_ptr)
  50{
  51   if (png_ptr == NULL)
  52      return;
  53
  54   switch (png_ptr->process_mode)
  55   {
  56      case PNG_READ_SIG_MODE:
  57      {
  58         png_push_read_sig(png_ptr, info_ptr);
  59         break;
  60      }
  61
  62      case PNG_READ_CHUNK_MODE:
  63      {
  64         png_push_read_chunk(png_ptr, info_ptr);
  65         break;
  66      }
  67
  68      case PNG_READ_IDAT_MODE:
  69      {
  70         png_push_read_IDAT(png_ptr);
  71         break;
  72      }
  73
  74#ifdef PNG_READ_tEXt_SUPPORTED
  75      case PNG_READ_tEXt_MODE:
  76      {
  77         png_push_read_tEXt(png_ptr, info_ptr);
  78         break;
  79      }
  80
  81#endif
  82#ifdef PNG_READ_zTXt_SUPPORTED
  83      case PNG_READ_zTXt_MODE:
  84      {
  85         png_push_read_zTXt(png_ptr, info_ptr);
  86         break;
  87      }
  88
  89#endif
  90#ifdef PNG_READ_iTXt_SUPPORTED
  91      case PNG_READ_iTXt_MODE:
  92      {
  93         png_push_read_iTXt(png_ptr, info_ptr);
  94         break;
  95      }
  96
  97#endif
  98      case PNG_SKIP_MODE:
  99      {
 100         png_push_crc_finish(png_ptr);
 101         break;
 102      }
 103
 104      default:
 105      {
 106         png_ptr->buffer_size = 0;
 107         break;
 108      }
 109   }
 110}
 111
 112/* Read any remaining signature bytes from the stream and compare them with
 113 * the correct PNG signature.  It is possible that this routine is called
 114 * with bytes already read from the signature, either because they have been
 115 * checked by the calling application, or because of multiple calls to this
 116 * routine.
 117 */
 118void /* PRIVATE */
 119png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
 120{
 121   png_size_t num_checked = png_ptr->sig_bytes,
 122             num_to_check = 8 - num_checked;
 123
 124   if (png_ptr->buffer_size < num_to_check)
 125   {
 126      num_to_check = png_ptr->buffer_size;
 127   }
 128
 129   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
 130      num_to_check);
 131   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
 132
 133   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
 134   {
 135      if (num_checked < 4 &&
 136          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
 137         png_error(png_ptr, "Not a PNG file");
 138      else
 139         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
 140   }
 141   else
 142   {
 143      if (png_ptr->sig_bytes >= 8)
 144      {
 145         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 146      }
 147   }
 148}
 149
 150void /* PRIVATE */
 151png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 152{
 153#ifdef PNG_USE_LOCAL_ARRAYS
 154      PNG_CONST PNG_IHDR;
 155      PNG_CONST PNG_IDAT;
 156      PNG_CONST PNG_IEND;
 157      PNG_CONST PNG_PLTE;
 158#ifdef PNG_READ_bKGD_SUPPORTED
 159      PNG_CONST PNG_bKGD;
 160#endif
 161#ifdef PNG_READ_cHRM_SUPPORTED
 162      PNG_CONST PNG_cHRM;
 163#endif
 164#ifdef PNG_READ_gAMA_SUPPORTED
 165      PNG_CONST PNG_gAMA;
 166#endif
 167#ifdef PNG_READ_hIST_SUPPORTED
 168      PNG_CONST PNG_hIST;
 169#endif
 170#ifdef PNG_READ_iCCP_SUPPORTED
 171      PNG_CONST PNG_iCCP;
 172#endif
 173#ifdef PNG_READ_iTXt_SUPPORTED
 174      PNG_CONST PNG_iTXt;
 175#endif
 176#ifdef PNG_READ_oFFs_SUPPORTED
 177      PNG_CONST PNG_oFFs;
 178#endif
 179#ifdef PNG_READ_pCAL_SUPPORTED
 180      PNG_CONST PNG_pCAL;
 181#endif
 182#ifdef PNG_READ_pHYs_SUPPORTED
 183      PNG_CONST PNG_pHYs;
 184#endif
 185#ifdef PNG_READ_sBIT_SUPPORTED
 186      PNG_CONST PNG_sBIT;
 187#endif
 188#ifdef PNG_READ_sCAL_SUPPORTED
 189      PNG_CONST PNG_sCAL;
 190#endif
 191#ifdef PNG_READ_sRGB_SUPPORTED
 192      PNG_CONST PNG_sRGB;
 193#endif
 194#ifdef PNG_READ_sPLT_SUPPORTED
 195      PNG_CONST PNG_sPLT;
 196#endif
 197#ifdef PNG_READ_tEXt_SUPPORTED
 198      PNG_CONST PNG_tEXt;
 199#endif
 200#ifdef PNG_READ_tIME_SUPPORTED
 201      PNG_CONST PNG_tIME;
 202#endif
 203#ifdef PNG_READ_tRNS_SUPPORTED
 204      PNG_CONST PNG_tRNS;
 205#endif
 206#ifdef PNG_READ_zTXt_SUPPORTED
 207      PNG_CONST PNG_zTXt;
 208#endif
 209#endif /* PNG_USE_LOCAL_ARRAYS */
 210
 211   /* First we make sure we have enough data for the 4 byte chunk name
 212    * and the 4 byte chunk length before proceeding with decoding the
 213    * chunk data.  To fully decode each of these chunks, we also make
 214    * sure we have enough data in the buffer for the 4 byte CRC at the
 215    * end of every chunk (except IDAT, which is handled separately).
 216    */
 217   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
 218   {
 219      png_byte chunk_length[4];
 220
 221      if (png_ptr->buffer_size < 8)
 222      {
 223         png_push_save_buffer(png_ptr);
 224         return;
 225      }
 226
 227      png_push_fill_buffer(png_ptr, chunk_length, 4);
 228      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
 229      png_reset_crc(png_ptr);
 230      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 231      png_check_chunk_name(png_ptr, png_ptr->chunk_name);
 232      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 233   }
 234
 235   if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 236     if (png_ptr->mode & PNG_AFTER_IDAT)
 237        png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
 238
 239   if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
 240   {
 241      if (png_ptr->push_length != 13)
 242         png_error(png_ptr, "Invalid IHDR length");
 243
 244      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 245      {
 246         png_push_save_buffer(png_ptr);
 247         return;
 248      }
 249
 250      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
 251   }
 252
 253   else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
 254   {
 255      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 256      {
 257         png_push_save_buffer(png_ptr);
 258         return;
 259      }
 260
 261      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
 262
 263      png_ptr->process_mode = PNG_READ_DONE_MODE;
 264      png_push_have_end(png_ptr, info_ptr);
 265   }
 266
 267#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 268   else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
 269   {
 270      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 271      {
 272         png_push_save_buffer(png_ptr);
 273         return;
 274      }
 275
 276      if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 277         png_ptr->mode |= PNG_HAVE_IDAT;
 278
 279      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
 280
 281      if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 282         png_ptr->mode |= PNG_HAVE_PLTE;
 283
 284      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 285      {
 286         if (!(png_ptr->mode & PNG_HAVE_IHDR))
 287            png_error(png_ptr, "Missing IHDR before IDAT");
 288
 289         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 290                  !(png_ptr->mode & PNG_HAVE_PLTE))
 291            png_error(png_ptr, "Missing PLTE before IDAT");
 292      }
 293   }
 294
 295#endif
 296   else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 297   {
 298      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 299      {
 300         png_push_save_buffer(png_ptr);
 301         return;
 302      }
 303      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
 304   }
 305
 306   else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 307   {
 308      /* If we reach an IDAT chunk, this means we have read all of the
 309       * header chunks, and we can start reading the image (or if this
 310       * is called after the image has been read - we have an error).
 311       */
 312
 313      if (!(png_ptr->mode & PNG_HAVE_IHDR))
 314         png_error(png_ptr, "Missing IHDR before IDAT");
 315
 316      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 317          !(png_ptr->mode & PNG_HAVE_PLTE))
 318         png_error(png_ptr, "Missing PLTE before IDAT");
 319
 320      if (png_ptr->mode & PNG_HAVE_IDAT)
 321      {
 322         if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
 323            if (png_ptr->push_length == 0)
 324               return;
 325
 326         if (png_ptr->mode & PNG_AFTER_IDAT)
 327            png_error(png_ptr, "Too many IDAT's found");
 328      }
 329
 330      png_ptr->idat_size = png_ptr->push_length;
 331      png_ptr->mode |= PNG_HAVE_IDAT;
 332      png_ptr->process_mode = PNG_READ_IDAT_MODE;
 333      png_push_have_info(png_ptr, info_ptr);
 334      png_ptr->zstream.avail_out =
 335          (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
 336          png_ptr->iwidth) + 1;
 337      png_ptr->zstream.next_out = png_ptr->row_buf;
 338      return;
 339   }
 340
 341#ifdef PNG_READ_gAMA_SUPPORTED
 342   else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
 343   {
 344      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 345      {
 346         png_push_save_buffer(png_ptr);
 347         return;
 348      }
 349
 350      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
 351   }
 352
 353#endif
 354#ifdef PNG_READ_sBIT_SUPPORTED
 355   else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
 356   {
 357      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 358      {
 359         png_push_save_buffer(png_ptr);
 360         return;
 361      }
 362
 363      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
 364   }
 365
 366#endif
 367#ifdef PNG_READ_cHRM_SUPPORTED
 368   else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
 369   {
 370      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 371      {
 372         png_push_save_buffer(png_ptr);
 373         return;
 374      }
 375
 376      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
 377   }
 378
 379#endif
 380#ifdef PNG_READ_sRGB_SUPPORTED
 381   else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
 382   {
 383      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 384      {
 385         png_push_save_buffer(png_ptr);
 386         return;
 387      }
 388
 389      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
 390   }
 391
 392#endif
 393#ifdef PNG_READ_iCCP_SUPPORTED
 394   else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
 395   {
 396      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 397      {
 398         png_push_save_buffer(png_ptr);
 399         return;
 400      }
 401
 402      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
 403   }
 404
 405#endif
 406#ifdef PNG_READ_sPLT_SUPPORTED
 407   else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
 408   {
 409      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 410      {
 411         png_push_save_buffer(png_ptr);
 412         return;
 413      }
 414
 415      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
 416   }
 417
 418#endif
 419#ifdef PNG_READ_tRNS_SUPPORTED
 420   else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
 421   {
 422      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 423      {
 424         png_push_save_buffer(png_ptr);
 425         return;
 426      }
 427
 428      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
 429   }
 430
 431#endif
 432#ifdef PNG_READ_bKGD_SUPPORTED
 433   else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
 434   {
 435      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 436      {
 437         png_push_save_buffer(png_ptr);
 438         return;
 439      }
 440
 441      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
 442   }
 443
 444#endif
 445#ifdef PNG_READ_hIST_SUPPORTED
 446   else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
 447   {
 448      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 449      {
 450         png_push_save_buffer(png_ptr);
 451         return;
 452      }
 453
 454      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
 455   }
 456
 457#endif
 458#ifdef PNG_READ_pHYs_SUPPORTED
 459   else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
 460   {
 461      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 462      {
 463         png_push_save_buffer(png_ptr);
 464         return;
 465      }
 466
 467      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
 468   }
 469
 470#endif
 471#ifdef PNG_READ_oFFs_SUPPORTED
 472   else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
 473   {
 474      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 475      {
 476         png_push_save_buffer(png_ptr);
 477         return;
 478      }
 479
 480      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
 481   }
 482#endif
 483
 484#ifdef PNG_READ_pCAL_SUPPORTED
 485   else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
 486   {
 487      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 488      {
 489         png_push_save_buffer(png_ptr);
 490         return;
 491      }
 492
 493      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
 494   }
 495
 496#endif
 497#ifdef PNG_READ_sCAL_SUPPORTED
 498   else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
 499   {
 500      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 501      {
 502         png_push_save_buffer(png_ptr);
 503         return;
 504      }
 505
 506      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
 507   }
 508
 509#endif
 510#ifdef PNG_READ_tIME_SUPPORTED
 511   else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
 512   {
 513      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 514      {
 515         png_push_save_buffer(png_ptr);
 516         return;
 517      }
 518
 519      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
 520   }
 521
 522#endif
 523#ifdef PNG_READ_tEXt_SUPPORTED
 524   else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
 525   {
 526      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 527      {
 528         png_push_save_buffer(png_ptr);
 529         return;
 530      }
 531
 532      png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
 533   }
 534
 535#endif
 536#ifdef PNG_READ_zTXt_SUPPORTED
 537   else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
 538   {
 539      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 540      {
 541         png_push_save_buffer(png_ptr);
 542         return;
 543      }
 544
 545      png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
 546   }
 547
 548#endif
 549#ifdef PNG_READ_iTXt_SUPPORTED
 550   else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
 551   {
 552      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 553      {
 554         png_push_save_buffer(png_ptr);
 555         return;
 556      }
 557
 558      png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
 559   }
 560
 561#endif
 562   else
 563   {
 564      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 565      {
 566         png_push_save_buffer(png_ptr);
 567         return;
 568      }
 569      png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
 570   }
 571
 572   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 573}
 574
 575void /* PRIVATE */
 576png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
 577{
 578   png_ptr->process_mode = PNG_SKIP_MODE;
 579   png_ptr->skip_length = skip;
 580}
 581
 582void /* PRIVATE */
 583png_push_crc_finish(png_structp png_ptr)
 584{
 585   if (png_ptr->skip_length && png_ptr->save_buffer_size)
 586   {
 587      png_size_t save_size;
 588
 589      if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
 590         save_size = (png_size_t)png_ptr->skip_length;
 591      else
 592         save_size = png_ptr->save_buffer_size;
 593
 594      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
 595
 596      png_ptr->skip_length -= save_size;
 597      png_ptr->buffer_size -= save_size;
 598      png_ptr->save_buffer_size -= save_size;
 599      png_ptr->save_buffer_ptr += save_size;
 600   }
 601   if (png_ptr->skip_length && png_ptr->current_buffer_size)
 602   {
 603      png_size_t save_size;
 604
 605      if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
 606         save_size = (png_size_t)png_ptr->skip_length;
 607      else
 608         save_size = png_ptr->current_buffer_size;
 609
 610      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
 611
 612      png_ptr->skip_length -= save_size;
 613      png_ptr->buffer_size -= save_size;
 614      png_ptr->current_buffer_size -= save_size;
 615      png_ptr->current_buffer_ptr += save_size;
 616   }
 617   if (!png_ptr->skip_length)
 618   {
 619      if (png_ptr->buffer_size < 4)
 620      {
 621         png_push_save_buffer(png_ptr);
 622         return;
 623      }
 624
 625      png_crc_finish(png_ptr, 0);
 626      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 627   }
 628}
 629
 630void PNGAPI
 631png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 632{
 633   png_bytep ptr;
 634
 635   if (png_ptr == NULL)
 636      return;
 637
 638   ptr = buffer;
 639   if (png_ptr->save_buffer_size)
 640   {
 641      png_size_t save_size;
 642
 643      if (length < png_ptr->save_buffer_size)
 644         save_size = length;
 645      else
 646         save_size = png_ptr->save_buffer_size;
 647
 648      png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
 649      length -= save_size;
 650      ptr += save_size;
 651      png_ptr->buffer_size -= save_size;
 652      png_ptr->save_buffer_size -= save_size;
 653      png_ptr->save_buffer_ptr += save_size;
 654   }
 655   if (length && png_ptr->current_buffer_size)
 656   {
 657      png_size_t save_size;
 658
 659      if (length < png_ptr->current_buffer_size)
 660         save_size = length;
 661
 662      else
 663         save_size = png_ptr->current_buffer_size;
 664
 665      png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
 666      png_ptr->buffer_size -= save_size;
 667      png_ptr->current_buffer_size -= save_size;
 668      png_ptr->current_buffer_ptr += save_size;
 669   }
 670}
 671
 672void /* PRIVATE */
 673png_push_save_buffer(png_structp png_ptr)
 674{
 675   if (png_ptr->save_buffer_size)
 676   {
 677      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
 678      {
 679         png_size_t i, istop;
 680         png_bytep sp;
 681         png_bytep dp;
 682
 683         istop = png_ptr->save_buffer_size;
 684         for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
 685            i < istop; i++, sp++, dp++)
 686         {
 687            *dp = *sp;
 688         }
 689      }
 690   }
 691   if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
 692      png_ptr->save_buffer_max)
 693   {
 694      png_size_t new_max;
 695      png_bytep old_buffer;
 696
 697      if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
 698         (png_ptr->current_buffer_size + 256))
 699      {
 700        png_error(png_ptr, "Potential overflow of save_buffer");
 701      }
 702
 703      new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
 704      old_buffer = png_ptr->save_buffer;
 705      png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
 706         (png_uint_32)new_max);
 707      if (png_ptr->save_buffer == NULL)
 708      {
 709        png_free(png_ptr, old_buffer);
 710        png_error(png_ptr, "Insufficient memory for save_buffer");
 711      }
 712      png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
 713      png_free(png_ptr, old_buffer);
 714      png_ptr->save_buffer_max = new_max;
 715   }
 716   if (png_ptr->current_buffer_size)
 717   {
 718      png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
 719         png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
 720      png_ptr->save_buffer_size += png_ptr->current_buffer_size;
 721      png_ptr->current_buffer_size = 0;
 722   }
 723   png_ptr->save_buffer_ptr = png_ptr->save_buffer;
 724   png_ptr->buffer_size = 0;
 725}
 726
 727void /* PRIVATE */
 728png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
 729   png_size_t buffer_length)
 730{
 731   png_ptr->current_buffer = buffer;
 732   png_ptr->current_buffer_size = buffer_length;
 733   png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
 734   png_ptr->current_buffer_ptr = png_ptr->current_buffer;
 735}
 736
 737void /* PRIVATE */
 738png_push_read_IDAT(png_structp png_ptr)
 739{
 740#ifdef PNG_USE_LOCAL_ARRAYS
 741   PNG_CONST PNG_IDAT;
 742#endif
 743   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
 744   {
 745      png_byte chunk_length[4];
 746
 747      if (png_ptr->buffer_size < 8)
 748      {
 749         png_push_save_buffer(png_ptr);
 750         return;
 751      }
 752
 753      png_push_fill_buffer(png_ptr, chunk_length, 4);
 754      png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
 755      png_reset_crc(png_ptr);
 756      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 757      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 758
 759      if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
 760      {
 761         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 762         if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
 763            png_error(png_ptr, "Not enough compressed data");
 764         return;
 765      }
 766
 767      png_ptr->idat_size = png_ptr->push_length;
 768   }
 769   if (png_ptr->idat_size && png_ptr->save_buffer_size)
 770   {
 771      png_size_t save_size;
 772
 773      if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
 774      {
 775         save_size = (png_size_t)png_ptr->idat_size;
 776
 777         /* Check for overflow */
 778         if ((png_uint_32)save_size != png_ptr->idat_size)
 779            png_error(png_ptr, "save_size overflowed in pngpread");
 780      }
 781      else
 782         save_size = png_ptr->save_buffer_size;
 783
 784      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
 785
 786      png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
 787
 788      png_ptr->idat_size -= save_size;
 789      png_ptr->buffer_size -= save_size;
 790      png_ptr->save_buffer_size -= save_size;
 791      png_ptr->save_buffer_ptr += save_size;
 792   }
 793   if (png_ptr->idat_size && png_ptr->current_buffer_size)
 794   {
 795      png_size_t save_size;
 796
 797      if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
 798      {
 799         save_size = (png_size_t)png_ptr->idat_size;
 800
 801         /* Check for overflow */
 802         if ((png_uint_32)save_size != png_ptr->idat_size)
 803            png_error(png_ptr, "save_size overflowed in pngpread");
 804      }
 805      else
 806         save_size = png_ptr->current_buffer_size;
 807
 808      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
 809
 810      png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
 811
 812      png_ptr->idat_size -= save_size;
 813      png_ptr->buffer_size -= save_size;
 814      png_ptr->current_buffer_size -= save_size;
 815      png_ptr->current_buffer_ptr += save_size;
 816   }
 817   if (!png_ptr->idat_size)
 818   {
 819      if (png_ptr->buffer_size < 4)
 820      {
 821         png_push_save_buffer(png_ptr);
 822         return;
 823      }
 824
 825      png_crc_finish(png_ptr, 0);
 826      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 827      png_ptr->mode |= PNG_AFTER_IDAT;
 828   }
 829}
 830
 831void /* PRIVATE */
 832png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
 833   png_size_t buffer_length)
 834{
 835   /* The caller checks for a non-zero buffer length. */
 836   if (!(buffer_length > 0) || buffer == NULL)
 837      png_error(png_ptr, "No IDAT data (internal error)");
 838
 839   /* This routine must process all the data it has been given
 840    * before returning, calling the row callback as required to
 841    * handle the uncompressed results.
 842    */
 843   png_ptr->zstream.next_in = buffer;
 844   png_ptr->zstream.avail_in = (uInt)buffer_length;
 845
 846   /* Keep going until the decompressed data is all processed
 847    * or the stream marked as finished.
 848    */
 849   while (png_ptr->zstream.avail_in > 0 &&
 850	  !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
 851   {
 852      int ret;
 853
 854      /* We have data for zlib, but we must check that zlib
 855       * has somewhere to put the results.  It doesn't matter
 856       * if we don't expect any results -- it may be the input
 857       * data is just the LZ end code.
 858       */
 859      if (!(png_ptr->zstream.avail_out > 0))
 860      {
 861         png_ptr->zstream.avail_out =
 862             (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
 863             png_ptr->iwidth) + 1;
 864         png_ptr->zstream.next_out = png_ptr->row_buf;
 865      }
 866
 867      /* Using Z_SYNC_FLUSH here means that an unterminated
 868       * LZ stream can still be handled (a stream with a missing
 869       * end code), otherwise (Z_NO_FLUSH) a future zlib
 870       * implementation might defer output and, therefore,
 871       * change the current behavior.  (See comments in inflate.c
 872       * for why this doesn't happen at present with zlib 1.2.5.)
 873       */
 874      ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
 875
 876      /* Check for any failure before proceeding. */
 877      if (ret != Z_OK && ret != Z_STREAM_END)
 878      {
 879	 /* Terminate the decompression. */
 880	 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 881
 882         /* This may be a truncated stream (missing or
 883	  * damaged end code).  Treat that as a warning.
 884	  */
 885         if (png_ptr->row_number >= png_ptr->num_rows ||
 886	     png_ptr->pass > 6)
 887	    png_warning(png_ptr, "Truncated compressed data in IDAT");
 888	 else
 889	    png_error(png_ptr, "Decompression error in IDAT");
 890
 891	 /* Skip the check on unprocessed input */
 892         return;
 893      }
 894
 895      /* Did inflate output any data? */
 896      if (png_ptr->zstream.next_out != png_ptr->row_buf)
 897      {
 898	 /* Is this unexpected data after the last row?
 899	  * If it is, artificially terminate the LZ output
 900	  * here.
 901	  */
 902         if (png_ptr->row_number >= png_ptr->num_rows ||
 903	     png_ptr->pass > 6)
 904         {
 905	    /* Extra data. */
 906	    png_warning(png_ptr, "Extra compressed data in IDAT");
 907            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 908	    /* Do no more processing; skip the unprocessed
 909	     * input check below.
 910	     */
 911            return;
 912	 }
 913
 914	 /* Do we have a complete row? */
 915	 if (png_ptr->zstream.avail_out == 0)
 916	    png_push_process_row(png_ptr);
 917      }
 918
 919      /* And check for the end of the stream. */
 920      if (ret == Z_STREAM_END)
 921	 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 922   }
 923
 924   /* All the data should have been processed, if anything
 925    * is left at this point we have bytes of IDAT data
 926    * after the zlib end code.
 927    */
 928   if (png_ptr->zstream.avail_in > 0)
 929      png_warning(png_ptr, "Extra compression data");
 930}
 931
 932void /* PRIVATE */
 933png_push_process_row(png_structp png_ptr)
 934{
 935   png_ptr->row_info.color_type = png_ptr->color_type;
 936   png_ptr->row_info.width = png_ptr->iwidth;
 937   png_ptr->row_info.channels = png_ptr->channels;
 938   png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 939   png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 940
 941   png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
 942       png_ptr->row_info.width);
 943
 944   png_read_filter_row(png_ptr, &(png_ptr->row_info),
 945       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 946       (int)(png_ptr->row_buf[0]));
 947
 948   png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
 949      png_ptr->rowbytes + 1);
 950
 951   if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
 952      png_do_read_transformations(png_ptr);
 953
 954#ifdef PNG_READ_INTERLACING_SUPPORTED
 955   /* Blow up interlaced rows to full size */
 956   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 957   {
 958      if (png_ptr->pass < 6)
 959/*       old interface (pre-1.0.9):
 960         png_do_read_interlace(&(png_ptr->row_info),
 961             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 962 */
 963         png_do_read_interlace(png_ptr);
 964
 965    switch (png_ptr->pass)
 966    {
 967         case 0:
 968         {
 969            int i;
 970            for (i = 0; i < 8 && png_ptr->pass == 0; i++)
 971            {
 972               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 973               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
 974            }
 975
 976            if (png_ptr->pass == 2) /* Pass 1 might be empty */
 977            {
 978               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 979               {
 980                  png_push_have_row(png_ptr, png_bytep_NULL);
 981                  png_read_push_finish_row(png_ptr);
 982               }
 983            }
 984
 985            if (png_ptr->pass == 4 && png_ptr->height <= 4)
 986            {
 987               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 988               {
 989                  png_push_have_row(png_ptr, png_bytep_NULL);
 990                  png_read_push_finish_row(png_ptr);
 991               }
 992            }
 993
 994            if (png_ptr->pass == 6 && png_ptr->height <= 4)
 995            {
 996                  png_push_have_row(png_ptr, png_bytep_NULL);
 997                png_read_push_finish_row(png_ptr);
 998            }
 999
1000            break;
1001         }
1002
1003         case 1:
1004         {
1005            int i;
1006            for (i = 0; i < 8 && png_ptr->pass == 1; i++)
1007            {
1008               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1009               png_read_push_finish_row(png_ptr);
1010            }
1011
1012            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
1013            {
1014               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1015               {
1016                  png_push_have_row(png_ptr, png_bytep_NULL);
1017                  png_read_push_finish_row(png_ptr);
1018               }
1019            }
1020
1021            break;
1022         }
1023
1024         case 2:
1025         {
1026            int i;
1027
1028            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1029            {
1030               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1031               png_read_push_finish_row(png_ptr);
1032            }
1033
1034            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1035            {
1036                  png_push_have_row(png_ptr, png_bytep_NULL);
1037               png_read_push_finish_row(png_ptr);
1038            }
1039
1040            if (png_ptr->pass == 4) /* Pass 3 might be empty */
1041            {
1042               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1043               {
1044                  png_push_have_row(png_ptr, png_bytep_NULL);
1045                  png_read_push_finish_row(png_ptr);
1046               }
1047            }
1048
1049            break;
1050         }
1051
1052         case 3:
1053         {
1054            int i;
1055
1056            for (i = 0; i < 4 && png_ptr->pass == 3; i++)
1057            {
1058               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1059               png_read_push_finish_row(png_ptr);
1060            }
1061
1062            if (png_ptr->pass == 4) /* Skip top two generated rows */
1063            {
1064               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1065               {
1066                  png_push_have_row(png_ptr, png_bytep_NULL);
1067                  png_read_push_finish_row(png_ptr);
1068               }
1069            }
1070
1071            break;
1072         }
1073
1074         case 4:
1075         {
1076            int i;
1077
1078            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1079            {
1080               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1081               png_read_push_finish_row(png_ptr);
1082            }
1083
1084            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1085            {
1086                  png_push_have_row(png_ptr, png_bytep_NULL);
1087               png_read_push_finish_row(png_ptr);
1088            }
1089
1090            if (png_ptr->pass == 6) /* Pass 5 might be empty */
1091            {
1092                  png_push_have_row(png_ptr, png_bytep_NULL);
1093               png_read_push_finish_row(png_ptr);
1094            }
1095
1096            break;
1097         }
1098
1099         case 5:
1100         {
1101            int i;
1102
1103            for (i = 0; i < 2 && png_ptr->pass == 5; i++)
1104            {
1105               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1106               png_read_push_finish_row(png_ptr);
1107            }
1108
1109            if (png_ptr->pass == 6) /* Skip top generated row */
1110            {
1111                  png_push_have_row(png_ptr, png_bytep_NULL);
1112               png_read_push_finish_row(png_ptr);
1113            }
1114
1115            break;
1116         }
1117         case 6:
1118         {
1119            png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1120            png_read_push_finish_row(png_ptr);
1121
1122            if (png_ptr->pass != 6)
1123               break;
1124
1125                  png_push_have_row(png_ptr, png_bytep_NULL);
1126            png_read_push_finish_row(png_ptr);
1127         }
1128      }
1129   }
1130   else
1131#endif
1132   {
1133      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1134      png_read_push_finish_row(png_ptr);
1135   }
1136}
1137
1138void /* PRIVATE */
1139png_read_push_finish_row(png_structp png_ptr)
1140{
1141#ifdef PNG_USE_LOCAL_ARRAYS
1142   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1143
1144   /* Start of interlace block */
1145   PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
1146
1147   /* Offset to next interlace block */
1148   PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1149
1150   /* Start of interlace block in the y direction */
1151   PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1152
1153   /* Offset to next interlace block in the y direction */
1154   PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1155
1156   /* Height of interlace block.  This is not currently used - if you need
1157    * it, uncomment it here and in png.h
1158   PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1159   */
1160#endif
1161
1162   png_ptr->row_number++;
1163   if (png_ptr->row_number < png_ptr->num_rows)
1164      return;
1165
1166#ifdef PNG_READ_INTERLACING_SUPPORTED
1167   if (png_ptr->interlaced)
1168   {
1169      png_ptr->row_number = 0;
1170      png_memset_check(png_ptr, png_ptr->prev_row, 0,
1171         png_ptr->rowbytes + 1);
1172      do
1173      {
1174         png_ptr->pass++;
1175         if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1176             (png_ptr->pass == 3 && png_ptr->width < 3) ||
1177             (png_ptr->pass == 5 && png_ptr->width < 2))
1178           png_ptr->pass++;
1179
1180         if (png_ptr->pass > 7)
1181            png_ptr->pass--;
1182
1183         if (png_ptr->pass >= 7)
1184            break;
1185
1186         png_ptr->iwidth = (png_ptr->width +
1187            png_pass_inc[png_ptr->pass] - 1 -
1188            png_pass_start[png_ptr->pass]) /
1189            png_pass_inc[png_ptr->pass];
1190
1191         if (png_ptr->transformations & PNG_INTERLACE)
1192            break;
1193
1194         png_ptr->num_rows = (png_ptr->height +
1195            png_pass_yinc[png_ptr->pass] - 1 -
1196            png_pass_ystart[png_ptr->pass]) /
1197            png_pass_yinc[png_ptr->pass];
1198
1199      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1200   }
1201#endif /* PNG_READ_INTERLACING_SUPPORTED */
1202}
1203
1204#ifdef PNG_READ_tEXt_SUPPORTED
1205void /* PRIVATE */
1206png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1207   length)
1208{
1209   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1210      {
1211         png_error(png_ptr, "Out of place tEXt");
1212         info_ptr = info_ptr; /* To quiet some compiler warnings */
1213      }
1214
1215#ifdef PNG_MAX_MALLOC_64K
1216   png_ptr->skip_length = 0;  /* This may not be necessary */
1217
1218   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1219   {
1220      png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1221      png_ptr->skip_length = length - (png_uint_32)65535L;
1222      length = (png_uint_32)65535L;
1223   }
1224#endif
1225
1226   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1227      (png_uint_32)(length + 1));
1228   png_ptr->current_text[length] = '\0';
1229   png_ptr->current_text_ptr = png_ptr->current_text;
1230   png_ptr->current_text_size = (png_size_t)length;
1231   png_ptr->current_text_left = (png_size_t)length;
1232   png_ptr->process_mode = PNG_READ_tEXt_MODE;
1233}
1234
1235void /* PRIVATE */
1236png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1237{
1238   if (png_ptr->buffer_size && png_ptr->current_text_left)
1239   {
1240      png_size_t text_size;
1241
1242      if (png_ptr->buffer_size < png_ptr->current_text_left)
1243         text_size = png_ptr->buffer_size;
1244
1245      else
1246         text_size = png_ptr->current_text_left;
1247
1248      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1249      png_ptr->current_text_left -= text_size;
1250      png_ptr->current_text_ptr += text_size;
1251   }
1252   if (!(png_ptr->current_text_left))
1253   {
1254      png_textp text_ptr;
1255      png_charp text;
1256      png_charp key;
1257      int ret;
1258
1259      if (png_ptr->buffer_size < 4)
1260      {
1261         png_push_save_buffer(png_ptr);
1262         return;
1263      }
1264
1265      png_push_crc_finish(png_ptr);
1266
1267#ifdef PNG_MAX_MALLOC_64K
1268      if (png_ptr->skip_length)
1269         return;
1270#endif
1271
1272      key = png_ptr->current_text;
1273
1274      for (text = key; *text; text++)
1275         /* Empty loop */ ;
1276
1277      if (text < key + png_ptr->current_text_size)
1278         text++;
1279
1280      text_ptr = (png_textp)png_malloc(png_ptr,
1281         (png_uint_32)png_sizeof(png_text));
1282      text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1283      text_ptr->key = key;
1284#ifdef PNG_iTXt_SUPPORTED
1285      text_ptr->lang = NULL;
1286      text_ptr->lang_key = NULL;
1287#endif
1288      text_ptr->text = text;
1289
1290      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1291
1292      png_free(png_ptr, key);
1293      png_free(png_ptr, text_ptr);
1294      png_ptr->current_text = NULL;
1295
1296      if (ret)
1297        png_warning(png_ptr, "Insufficient memory to store text chunk.");
1298   }
1299}
1300#endif
1301
1302#ifdef PNG_READ_zTXt_SUPPORTED
1303void /* PRIVATE */
1304png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1305   length)
1306{
1307   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1308      {
1309         png_error(png_ptr, "Out of place zTXt");
1310         info_ptr = info_ptr; /* To quiet some compiler warnings */
1311      }
1312
1313#ifdef PNG_MAX_MALLOC_64K
1314   /* We can't handle zTXt chunks > 64K, since we don't have enough space
1315    * to be able to store the uncompressed data.  Actually, the threshold
1316    * is probably around 32K, but it isn't as definite as 64K is.
1317    */
1318   if (length > (png_uint_32)65535L)
1319   {
1320      png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1321      png_push_crc_skip(png_ptr, length);
1322      return;
1323   }
1324#endif
1325
1326   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1327      (png_uint_32)(length + 1));
1328   png_ptr->current_text[length] = '\0';
1329   png_ptr->current_text_ptr = png_ptr->current_text;
1330   png_ptr->current_text_size = (png_size_t)length;
1331   png_ptr->current_text_left = (png_size_t)length;
1332   png_ptr->process_mode = PNG_READ_zTXt_MODE;
1333}
1334
1335void /* PRIVATE */
1336png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1337{
1338   if (png_ptr->buffer_size && png_ptr->current_text_left)
1339   {
1340      png_size_t text_size;
1341
1342      if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1343         text_size = png_ptr->buffer_size;
1344
1345      else
1346         text_size = png_ptr->current_text_left;
1347
1348      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1349      png_ptr->current_text_left -= text_size;
1350      png_ptr->current_text_ptr += text_size;
1351   }
1352   if (!(png_ptr->current_text_left))
1353   {
1354      png_textp text_ptr;
1355      png_charp text;
1356      png_charp key;
1357      int ret;
1358      png_size_t text_size, key_size;
1359
1360      if (png_ptr->buffer_size < 4)
1361      {
1362         png_push_save_buffer(png_ptr);
1363         return;
1364      }
1365
1366      png_push_crc_finish(png_ptr);
1367
1368      key = png_ptr->current_text;
1369
1370      for (text = key; *text; text++)
1371         /* Empty loop */ ;
1372
1373      /* zTXt can't have zero text */
1374      if (text >= key + png_ptr->current_text_size)
1375      {
1376         png_ptr->current_text = NULL;
1377         png_free(png_ptr, key);
1378         return;
1379      }
1380
1381      text++;
1382
1383      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* Check compression byte */
1384      {
1385         png_ptr->current_text = NULL;
1386         png_free(png_ptr, key);
1387         return;
1388      }
1389
1390      text++;
1391
1392      png_ptr->zstream.next_in = (png_bytep )text;
1393      png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1394         (text - key));
1395      png_ptr->zstream.next_out = png_ptr->zbuf;
1396      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1397
1398      key_size = text - key;
1399      text_size = 0;
1400      text = NULL;
1401      ret = Z_STREAM_END;
1402
1403      while (png_ptr->zstream.avail_in)
1404      {
1405         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1406         if (ret != Z_OK && ret != Z_STREAM_END)
1407         {
1408            inflateReset(&png_ptr->zstream);
1409            png_ptr->zstream.avail_in = 0;
1410            png_ptr->current_text = NULL;
1411            png_free(png_ptr, key);
1412            png_free(png_ptr, text);
1413            return;
1414         }
1415         if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1416         {
1417            if (text == NULL)
1418            {
1419               text = (png_charp)png_malloc(png_ptr,
1420                     (png_uint_32)(png_ptr->zbuf_size
1421                     - png_ptr->zstream.avail_out + key_size + 1));
1422
1423               png_memcpy(text + key_size, png_ptr->zbuf,
1424                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1425
1426               png_memcpy(text, key, key_size);
1427
1428               text_size = key_size + png_ptr->zbuf_size -
1429                  png_ptr->zstream.avail_out;
1430
1431               *(text + text_size) = '\0';
1432            }
1433            else
1434            {
1435               png_charp tmp;
1436
1437               tmp = text;
1438               text = (png_charp)png_malloc(png_ptr, text_size +
1439                  (png_uint_32)(png_ptr->zbuf_size 
1440                  - png_ptr->zstream.avail_out + 1));
1441
1442               png_memcpy(text, tmp, text_size);
1443               png_free(png_ptr, tmp);
1444
1445               png_memcpy(text + text_size, png_ptr->zbuf,
1446                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1447
1448               text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1449               *(text + text_size) = '\0';
1450            }
1451            if (ret != Z_STREAM_END)
1452            {
1453               png_ptr->zstream.next_out = png_ptr->zbuf;
1454               png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1455            }
1456         }
1457         else
1458         {
1459            break;
1460         }
1461
1462         if (ret == Z_STREAM_END)
1463            break;
1464      }
1465
1466      inflateReset(&png_ptr->zstream);
1467      png_ptr->zstream.avail_in = 0;
1468
1469      if (ret != Z_STREAM_END)
1470      {
1471         png_ptr->current_text = NULL;
1472         png_free(png_ptr, key);
1473         png_free(png_ptr, text);
1474         return;
1475      }
1476
1477      png_ptr->current_text = NULL;
1478      png_free(png_ptr, key);
1479      key = text;
1480      text += key_size;
1481
1482      text_ptr = (png_textp)png_malloc(png_ptr,
1483          (png_uint_32)png_sizeof(png_text));
1484      text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1485      text_ptr->key = key;
1486#ifdef PNG_iTXt_SUPPORTED
1487      text_ptr->lang = NULL;
1488      text_ptr->lang_key = NULL;
1489#endif
1490      text_ptr->text = text;
1491
1492      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1493
1494      png_free(png_ptr, key);
1495      png_free(png_ptr, text_ptr);
1496
1497      if (ret)
1498        png_warning(png_ptr, "Insufficient memory to store text chunk.");
1499   }
1500}
1501#endif
1502
1503#ifdef PNG_READ_iTXt_SUPPORTED
1504void /* PRIVATE */
1505png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1506   length)
1507{
1508   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1509      {
1510         png_error(png_ptr, "Out of place iTXt");
1511         info_ptr = info_ptr; /* To quiet some compiler warnings */
1512      }
1513
1514#ifdef PNG_MAX_MALLOC_64K
1515   png_ptr->skip_length = 0;  /* This may not be necessary */
1516
1517   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1518   {
1519      png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1520      png_ptr->skip_length = length - (png_uint_32)65535L;
1521      length = (png_uint_32)65535L;
1522   }
1523#endif
1524
1525   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1526      (png_uint_32)(length + 1));
1527   png_ptr->current_text[length] = '\0';
1528   png_ptr->current_text_ptr = png_ptr->current_text;
1529   png_ptr->current_text_size = (png_size_t)length;
1530   png_ptr->current_text_left = (png_size_t)length;
1531   png_ptr->process_mode = PNG_READ_iTXt_MODE;
1532}
1533
1534void /* PRIVATE */
1535png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1536{
1537
1538   if (png_ptr->buffer_size && png_ptr->current_text_left)
1539   {
1540      png_size_t text_size;
1541
1542      if (png_ptr->buffer_size < png_ptr->current_text_left)
1543         text_size = png_ptr->buffer_size;
1544
1545      else
1546         text_size = png_ptr->current_text_left;
1547
1548      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1549      png_ptr->current_text_left -= text_size;
1550      png_ptr->current_text_ptr += text_size;
1551   }
1552   if (!(png_ptr->current_text_left))
1553   {
1554      png_textp text_ptr;
1555      png_charp key;
1556      int comp_flag;
1557      png_charp lang;
1558      png_charp lang_key;
1559      png_charp text;
1560      int ret;
1561
1562      if (png_ptr->buffer_size < 4)
1563      {
1564         png_push_save_buffer(png_ptr);
1565         return;
1566      }
1567
1568      png_push_crc_finish(png_ptr);
1569
1570#ifdef PNG_MAX_MALLOC_64K
1571      if (png_ptr->skip_length)
1572         return;
1573#endif
1574
1575      key = png_ptr->current_text;
1576
1577      for (lang = key; *lang; lang++)
1578         /* Empty loop */ ;
1579
1580      if (lang < key + png_ptr->current_text_size - 3)
1581         lang++;
1582
1583      comp_flag = *lang++;
1584      lang++;     /* Skip comp_type, always zero */
1585
1586      for (lang_key = lang; *lang_key; lang_key++)
1587         /* Empty loop */ ;
1588
1589      lang_key++;        /* Skip NUL separator */
1590
1591      text=lang_key;
1592
1593      if (lang_key < key + png_ptr->current_text_size - 1)
1594      {
1595        for (; *text; text++)
1596           /* Empty loop */ ;
1597      }
1598
1599      if (text < key + png_ptr->current_text_size)
1600         text++;
1601
1602      text_ptr = (png_textp)png_malloc(png_ptr,
1603         (png_uint_32)png_sizeof(png_text));
1604
1605      text_ptr->compression = comp_flag + 2;
1606      text_ptr->key = key;
1607      text_ptr->lang = lang;
1608      text_ptr->lang_key = lang_key;
1609      text_ptr->text = text;
1610      text_ptr->text_length = 0;
1611      text_ptr->itxt_length = png_strlen(text);
1612
1613      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1614
1615      png_ptr->current_text = NULL;
1616
1617      png_free(png_ptr, text_ptr);
1618      if (ret)
1619         png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
1620   }
1621}
1622#endif
1623
1624/* This function is called when we haven't found a handler for this
1625 * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
1626 * name or a critical chunk), the chunk is (currently) silently ignored.
1627 */
1628void /* PRIVATE */
1629png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1630   length)
1631{
1632   png_uint_32 skip = 0;
1633
1634   if (!(png_ptr->chunk_name[0] & 0x20))
1635   {
1636#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1637      if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1638         PNG_HANDLE_CHUNK_ALWAYS
1639#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1640         && png_ptr->read_user_chunk_fn == NULL
1641#endif
1642         )
1643#endif
1644         png_chunk_error(png_ptr, "unknown critical chunk");
1645
1646      info_ptr = info_ptr; /* To quiet some compiler warnings */
1647   }
1648
1649#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1650   if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1651   {
1652#ifdef PNG_MAX_MALLOC_64K
1653      if (length > (png_uint_32)65535L)
1654      {
1655          png_warning(png_ptr, "unknown chunk too large to fit in memory");
1656          skip = length - (png_uint_32)65535L;
1657          length = (png_uint_32)65535L;
1658      }
1659#endif
1660      png_memcpy((png_charp)png_ptr->unknown_chunk.name,
1661                 (png_charp)png_ptr->chunk_name, 
1662                 png_sizeof(png_ptr->unknown_chunk.name));
1663      png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name) - 1]
1664        = '\0';
1665
1666      png_ptr->unknown_chunk.size = (png_size_t)length;
1667
1668      if (length == 0)
1669         png_ptr->unknown_chunk.data = NULL;
1670
1671      else
1672      {
1673         png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
1674            (png_uint_32)length);
1675         png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
1676      }
1677
1678#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1679      if (png_ptr->read_user_chunk_fn != NULL)
1680      {
1681         /* Callback to user unknown chunk handler */
1682         int ret;
1683         ret = (*(png_ptr->read_user_chunk_fn))
1684           (png_ptr, &png_ptr->unknown_chunk);
1685
1686         if (ret < 0)
1687            png_chunk_error(png_ptr, "error in user chunk");
1688
1689         if (ret == 0)
1690         {
1691            if (!(png_ptr->chunk_name[0] & 0x20))
1692               if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1693                    PNG_HANDLE_CHUNK_ALWAYS)
1694                  png_chunk_error(png_ptr, "unknown critical chunk");
1695            png_set_unknown_chunks(png_ptr, info_ptr,
1696               &png_ptr->unknown_chunk, 1);
1697         }
1698      }
1699
1700      else
1701#endif
1702        png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
1703      png_free(png_ptr, png_ptr->unknown_chunk.data);
1704      png_ptr->unknown_chunk.data = NULL;
1705   }
1706
1707   else
1708#endif
1709      skip=length;
1710   png_push_crc_skip(png_ptr, skip);
1711}
1712
1713void /* PRIVATE */
1714png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1715{
1716   if (png_ptr->info_fn != NULL)
1717      (*(png_ptr->info_fn))(png_ptr, info_ptr);
1718}
1719
1720void /* PRIVATE */
1721png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1722{
1723   if (png_ptr->end_fn != NULL)
1724      (*(png_ptr->end_fn))(png_ptr, info_ptr);
1725}
1726
1727void /* PRIVATE */
1728png_push_have_row(png_structp png_ptr, png_bytep row)
1729{
1730   if (png_ptr->row_fn != NULL)
1731      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1732         (int)png_ptr->pass);
1733}
1734
1735void PNGAPI
1736png_progressive_combine_row (png_structp png_ptr,
1737   png_bytep old_row, png_bytep new_row)
1738{
1739#ifdef PNG_USE_LOCAL_ARRAYS
1740   PNG_CONST int FARDATA png_pass_dsp_mask[7] =
1741      {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1742#endif
1743
1744   if (png_ptr == NULL)
1745      return;
1746
1747   if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
1748      png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1749}
1750
1751void PNGAPI
1752png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1753   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1754   png_progressive_end_ptr end_fn)
1755{
1756   if (png_ptr == NULL)
1757      return;
1758
1759   png_ptr->info_fn = info_fn;
1760   png_ptr->row_fn = row_fn;
1761   png_ptr->end_fn = end_fn;
1762
1763   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1764}
1765
1766png_voidp PNGAPI
1767png_get_progressive_ptr(png_structp png_ptr)
1768{
1769   if (png_ptr == NULL)
1770      return (NULL);
1771
1772   return png_ptr->io_ptr;
1773}
1774#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */