src/png/pngpread.c

   1
   2 /* pngpread.c - read a png file in push mode
   3  *
   4  * libpng 1.2.5rc3 - September 18, 2002
   5  * For conditions of distribution and use, see copyright notice in png.h
   6  * Copyright (c) 1998-2002 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
  11 #define PNG_INTERNAL
  12 #include "png.h"
  13
  14 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
  15
  16 /* push model modes */
  17 #define PNG_READ_SIG_MODE   0
  18 #define PNG_READ_CHUNK_MODE 1
  19 #define PNG_READ_IDAT_MODE  2
  20 #define PNG_SKIP_MODE       3
  21 #define PNG_READ_tEXt_MODE  4
  22 #define PNG_READ_zTXt_MODE  5
  23 #define PNG_READ_DONE_MODE  6
  24 #define PNG_READ_iTXt_MODE  7
  25 #define PNG_ERROR_MODE      8
  26
  27 void PNGAPI
  28 png_process_data(png_structp png_ptr, png_infop info_ptr,
  29    png_bytep buffer, png_size_t buffer_size)
  30 {
  31    png_push_restore_buffer(png_ptr, buffer, buffer_size);
  32
  33    while (png_ptr->buffer_size)
  34    {
  35       png_process_some_data(png_ptr, info_ptr);
  36    }
  37 }
  38
  39 /* What we do with the incoming data depends on what we were previously
  40  * doing before we ran out of data...
  41  */
  42 void /* PRIVATE */
  43 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
  44 {
  45    switch (png_ptr->process_mode)
  46    {
  47       case PNG_READ_SIG_MODE:
  48       {
  49          png_push_read_sig(png_ptr, info_ptr);
  50          break;
  51       }
  52       case PNG_READ_CHUNK_MODE:
  53       {
  54          png_push_read_chunk(png_ptr, info_ptr);
  55          break;
  56       }
  57       case PNG_READ_IDAT_MODE:
  58       {
  59          png_push_read_IDAT(png_ptr);
  60          break;
  61       }
  62 #if defined(PNG_READ_tEXt_SUPPORTED)
  63       case PNG_READ_tEXt_MODE:
  64       {
  65          png_push_read_tEXt(png_ptr, info_ptr);
  66          break;
  67       }
  68 #endif
  69 #if defined(PNG_READ_zTXt_SUPPORTED)
  70       case PNG_READ_zTXt_MODE:
  71       {
  72          png_push_read_zTXt(png_ptr, info_ptr);
  73          break;
  74       }
  75 #endif
  76 #if defined(PNG_READ_iTXt_SUPPORTED)
  77       case PNG_READ_iTXt_MODE:
  78       {
  79          png_push_read_iTXt(png_ptr, info_ptr);
  80          break;
  81       }
  82 #endif
  83       case PNG_SKIP_MODE:
  84       {
  85          png_push_crc_finish(png_ptr);
  86          break;
  87       }
  88       default:
  89       {
  90          png_ptr->buffer_size = 0;
  91          break;
  92       }
  93    }
  94 }
  95
  96 /* Read any remaining signature bytes from the stream and compare them with
  97  * the correct PNG signature.  It is possible that this routine is called
  98  * with bytes already read from the signature, either because they have been
  99  * checked by the calling application, or because of multiple calls to this
 100  * routine.
 101  */
 102 void /* PRIVATE */
 103 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
 104 {
 105    png_size_t num_checked = png_ptr->sig_bytes,
 106              num_to_check = 8 - num_checked;
 107
 108    if (png_ptr->buffer_size < num_to_check)
 109    {
 110       num_to_check = png_ptr->buffer_size;
 111    }
 112
 113    png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
 114       num_to_check);
 115    png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);
 116
 117    if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
 118    {
 119       if (num_checked < 4 &&
 120           png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
 121          png_error(png_ptr, "Not a PNG file");
 122       else
 123          png_error(png_ptr, "PNG file corrupted by ASCII conversion");
 124    }
 125    else
 126    {
 127       if (png_ptr->sig_bytes >= 8)
 128       {
 129          png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 130       }
 131    }
 132 }
 133
 134 void /* PRIVATE */
 135 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
 136 {
 137 #ifdef PNG_USE_LOCAL_ARRAYS
 138       PNG_IHDR;
 139       PNG_IDAT;
 140       PNG_IEND;
 141       PNG_PLTE;
 142 #if defined(PNG_READ_bKGD_SUPPORTED)
 143       PNG_bKGD;
 144 #endif
 145 #if defined(PNG_READ_cHRM_SUPPORTED)
 146       PNG_cHRM;
 147 #endif
 148 #if defined(PNG_READ_gAMA_SUPPORTED)
 149       PNG_gAMA;
 150 #endif
 151 #if defined(PNG_READ_hIST_SUPPORTED)
 152       PNG_hIST;
 153 #endif
 154 #if defined(PNG_READ_iCCP_SUPPORTED)
 155       PNG_iCCP;
 156 #endif
 157 #if defined(PNG_READ_iTXt_SUPPORTED)
 158       PNG_iTXt;
 159 #endif
 160 #if defined(PNG_READ_oFFs_SUPPORTED)
 161       PNG_oFFs;
 162 #endif
 163 #if defined(PNG_READ_pCAL_SUPPORTED)
 164       PNG_pCAL;
 165 #endif
 166 #if defined(PNG_READ_pHYs_SUPPORTED)
 167       PNG_pHYs;
 168 #endif
 169 #if defined(PNG_READ_sBIT_SUPPORTED)
 170       PNG_sBIT;
 171 #endif
 172 #if defined(PNG_READ_sCAL_SUPPORTED)
 173       PNG_sCAL;
 174 #endif
 175 #if defined(PNG_READ_sRGB_SUPPORTED)
 176       PNG_sRGB;
 177 #endif
 178 #if defined(PNG_READ_sPLT_SUPPORTED)
 179       PNG_sPLT;
 180 #endif
 181 #if defined(PNG_READ_tEXt_SUPPORTED)
 182       PNG_tEXt;
 183 #endif
 184 #if defined(PNG_READ_tIME_SUPPORTED)
 185       PNG_tIME;
 186 #endif
 187 #if defined(PNG_READ_tRNS_SUPPORTED)
 188       PNG_tRNS;
 189 #endif
 190 #if defined(PNG_READ_zTXt_SUPPORTED)
 191       PNG_zTXt;
 192 #endif
 193 #endif /* PNG_USE_LOCAL_ARRAYS */
 194    /* First we make sure we have enough data for the 4 byte chunk name
 195     * and the 4 byte chunk length before proceeding with decoding the
 196     * chunk data.  To fully decode each of these chunks, we also make
 197     * sure we have enough data in the buffer for the 4 byte CRC at the
 198     * end of every chunk (except IDAT, which is handled separately).
 199     */
 200    if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
 201    {
 202       png_byte chunk_length[4];
 203
 204       if (png_ptr->buffer_size < 8)
 205       {
 206          png_push_save_buffer(png_ptr);
 207          return;
 208       }
 209
 210       png_push_fill_buffer(png_ptr, chunk_length, 4);
 211       png_ptr->push_length = png_get_uint_32(chunk_length);
 212       png_reset_crc(png_ptr);
 213       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 214       png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 215    }
 216
 217    if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
 218    {
 219       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 220       {
 221          png_push_save_buffer(png_ptr);
 222          return;
 223       }
 224       png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
 225    }
 226    else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
 227    {
 228       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 229       {
 230          png_push_save_buffer(png_ptr);
 231          return;
 232       }
 233       png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
 234    }
 235    else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
 236    {
 237       /* If we reach an IDAT chunk, this means we have read all of the
 238        * header chunks, and we can start reading the image (or if this
 239        * is called after the image has been read - we have an error).
 240        */
 241      if (!(png_ptr->mode & PNG_HAVE_IHDR))
 242        png_error(png_ptr, "Missing IHDR before IDAT");
 243      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
 244          !(png_ptr->mode & PNG_HAVE_PLTE))
 245        png_error(png_ptr, "Missing PLTE before IDAT");
 246
 247       if (png_ptr->mode & PNG_HAVE_IDAT)
 248       {
 249          if (png_ptr->push_length == 0)
 250             return;
 251
 252          if (png_ptr->mode & PNG_AFTER_IDAT)
 253             png_error(png_ptr, "Too many IDAT's found");
 254       }
 255
 256       png_ptr->idat_size = png_ptr->push_length;
 257       png_ptr->mode |= PNG_HAVE_IDAT;
 258       png_ptr->process_mode = PNG_READ_IDAT_MODE;
 259       png_push_have_info(png_ptr, info_ptr);
 260       png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
 261       png_ptr->zstream.next_out = png_ptr->row_buf;
 262       return;
 263    }
 264    else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
 265    {
 266       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 267       {
 268          png_push_save_buffer(png_ptr);
 269          return;
 270       }
 271       png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
 272
 273       png_ptr->process_mode = PNG_READ_DONE_MODE;
 274       png_push_have_end(png_ptr, info_ptr);
 275    }
 276 #if defined(PNG_READ_gAMA_SUPPORTED)
 277    else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
 278    {
 279       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 280       {
 281          png_push_save_buffer(png_ptr);
 282          return;
 283       }
 284       png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
 285    }
 286 #endif
 287 #if defined(PNG_READ_sBIT_SUPPORTED)
 288    else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
 289    {
 290       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 291       {
 292          png_push_save_buffer(png_ptr);
 293          return;
 294       }
 295       png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
 296    }
 297 #endif
 298 #if defined(PNG_READ_cHRM_SUPPORTED)
 299    else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
 300    {
 301       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 302       {
 303          png_push_save_buffer(png_ptr);
 304          return;
 305       }
 306       png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
 307    }
 308 #endif
 309 #if defined(PNG_READ_sRGB_SUPPORTED)
 310    else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
 311    {
 312       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 313       {
 314          png_push_save_buffer(png_ptr);
 315          return;
 316       }
 317       png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
 318    }
 319 #endif
 320 #if defined(PNG_READ_iCCP_SUPPORTED)
 321    else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
 322    {
 323       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 324       {
 325          png_push_save_buffer(png_ptr);
 326          return;
 327       }
 328       png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
 329    }
 330 #endif
 331 #if defined(PNG_READ_sPLT_SUPPORTED)
 332    else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
 333    {
 334       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 335       {
 336          png_push_save_buffer(png_ptr);
 337          return;
 338       }
 339       png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
 340    }
 341 #endif
 342 #if defined(PNG_READ_tRNS_SUPPORTED)
 343    else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
 344    {
 345       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 346       {
 347          png_push_save_buffer(png_ptr);
 348          return;
 349       }
 350       png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
 351    }
 352 #endif
 353 #if defined(PNG_READ_bKGD_SUPPORTED)
 354    else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
 355    {
 356       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 357       {
 358          png_push_save_buffer(png_ptr);
 359          return;
 360       }
 361       png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
 362    }
 363 #endif
 364 #if defined(PNG_READ_hIST_SUPPORTED)
 365    else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
 366    {
 367       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 368       {
 369          png_push_save_buffer(png_ptr);
 370          return;
 371       }
 372       png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
 373    }
 374 #endif
 375 #if defined(PNG_READ_pHYs_SUPPORTED)
 376    else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
 377    {
 378       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 379       {
 380          png_push_save_buffer(png_ptr);
 381          return;
 382       }
 383       png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
 384    }
 385 #endif
 386 #if defined(PNG_READ_oFFs_SUPPORTED)
 387    else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
 388    {
 389       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 390       {
 391          png_push_save_buffer(png_ptr);
 392          return;
 393       }
 394       png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
 395    }
 396 #endif
 397 #if defined(PNG_READ_pCAL_SUPPORTED)
 398    else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
 399    {
 400       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 401       {
 402          png_push_save_buffer(png_ptr);
 403          return;
 404       }
 405       png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
 406    }
 407 #endif
 408 #if defined(PNG_READ_sCAL_SUPPORTED)
 409    else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
 410    {
 411       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 412       {
 413          png_push_save_buffer(png_ptr);
 414          return;
 415       }
 416       png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
 417    }
 418 #endif
 419 #if defined(PNG_READ_tIME_SUPPORTED)
 420    else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 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       png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
 428    }
 429 #endif
 430 #if defined(PNG_READ_tEXt_SUPPORTED)
 431    else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
 432    {
 433       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 434       {
 435          png_push_save_buffer(png_ptr);
 436          return;
 437       }
 438       png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
 439    }
 440 #endif
 441 #if defined(PNG_READ_zTXt_SUPPORTED)
 442    else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
 443    {
 444       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 445       {
 446          png_push_save_buffer(png_ptr);
 447          return;
 448       }
 449       png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
 450    }
 451 #endif
 452 #if defined(PNG_READ_iTXt_SUPPORTED)
 453    else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
 454    {
 455       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 456       {
 457          png_push_save_buffer(png_ptr);
 458          return;
 459       }
 460       png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
 461    }
 462 #endif
 463    else
 464    {
 465       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
 466       {
 467          png_push_save_buffer(png_ptr);
 468          return;
 469       }
 470       png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
 471    }
 472
 473    png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 474 }
 475
 476 void /* PRIVATE */
 477 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
 478 {
 479    png_ptr->process_mode = PNG_SKIP_MODE;
 480    png_ptr->skip_length = skip;
 481 }
 482
 483 void /* PRIVATE */
 484 png_push_crc_finish(png_structp png_ptr)
 485 {
 486    if (png_ptr->skip_length && png_ptr->save_buffer_size)
 487    {
 488       png_size_t save_size;
 489
 490       if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
 491          save_size = (png_size_t)png_ptr->skip_length;
 492       else
 493          save_size = png_ptr->save_buffer_size;
 494
 495       png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
 496
 497       png_ptr->skip_length -= save_size;
 498       png_ptr->buffer_size -= save_size;
 499       png_ptr->save_buffer_size -= save_size;
 500       png_ptr->save_buffer_ptr += save_size;
 501    }
 502    if (png_ptr->skip_length && png_ptr->current_buffer_size)
 503    {
 504       png_size_t save_size;
 505
 506       if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
 507          save_size = (png_size_t)png_ptr->skip_length;
 508       else
 509          save_size = png_ptr->current_buffer_size;
 510
 511       png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
 512
 513       png_ptr->skip_length -= save_size;
 514       png_ptr->buffer_size -= save_size;
 515       png_ptr->current_buffer_size -= save_size;
 516       png_ptr->current_buffer_ptr += save_size;
 517    }
 518    if (!png_ptr->skip_length)
 519    {
 520       if (png_ptr->buffer_size < 4)
 521       {
 522          png_push_save_buffer(png_ptr);
 523          return;
 524       }
 525
 526       png_crc_finish(png_ptr, 0);
 527       png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 528    }
 529 }
 530
 531 void PNGAPI
 532 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 533 {
 534    png_bytep ptr;
 535
 536    ptr = buffer;
 537    if (png_ptr->save_buffer_size)
 538    {
 539       png_size_t save_size;
 540
 541       if (length < png_ptr->save_buffer_size)
 542          save_size = length;
 543       else
 544          save_size = png_ptr->save_buffer_size;
 545
 546       png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
 547       length -= save_size;
 548       ptr += save_size;
 549       png_ptr->buffer_size -= save_size;
 550       png_ptr->save_buffer_size -= save_size;
 551       png_ptr->save_buffer_ptr += save_size;
 552    }
 553    if (length && png_ptr->current_buffer_size)
 554    {
 555       png_size_t save_size;
 556
 557       if (length < png_ptr->current_buffer_size)
 558          save_size = length;
 559       else
 560          save_size = png_ptr->current_buffer_size;
 561
 562       png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
 563       png_ptr->buffer_size -= save_size;
 564       png_ptr->current_buffer_size -= save_size;
 565       png_ptr->current_buffer_ptr += save_size;
 566    }
 567 }
 568
 569 void /* PRIVATE */
 570 png_push_save_buffer(png_structp png_ptr)
 571 {
 572    if (png_ptr->save_buffer_size)
 573    {
 574       if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
 575       {
 576          png_size_t i,istop;
 577          png_bytep sp;
 578          png_bytep dp;
 579
 580          istop = png_ptr->save_buffer_size;
 581          for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
 582             i < istop; i++, sp++, dp++)
 583          {
 584             *dp = *sp;
 585          }
 586       }
 587    }
 588    if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
 589       png_ptr->save_buffer_max)
 590    {
 591       png_size_t new_max;
 592       png_bytep old_buffer;
 593
 594       new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
 595       old_buffer = png_ptr->save_buffer;
 596       png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
 597          (png_uint_32)new_max);
 598       png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
 599       png_free(png_ptr, old_buffer);
 600       png_ptr->save_buffer_max = new_max;
 601    }
 602    if (png_ptr->current_buffer_size)
 603    {
 604       png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
 605          png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
 606       png_ptr->save_buffer_size += png_ptr->current_buffer_size;
 607       png_ptr->current_buffer_size = 0;
 608    }
 609    png_ptr->save_buffer_ptr = png_ptr->save_buffer;
 610    png_ptr->buffer_size = 0;
 611 }
 612
 613 void /* PRIVATE */
 614 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
 615    png_size_t buffer_length)
 616 {
 617    png_ptr->current_buffer = buffer;
 618    png_ptr->current_buffer_size = buffer_length;
 619    png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
 620    png_ptr->current_buffer_ptr = png_ptr->current_buffer;
 621 }
 622
 623 void /* PRIVATE */
 624 png_push_read_IDAT(png_structp png_ptr)
 625 {
 626 #ifdef PNG_USE_LOCAL_ARRAYS
 627    PNG_IDAT;
 628 #endif
 629    if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
 630    {
 631       png_byte chunk_length[4];
 632
 633       if (png_ptr->buffer_size < 8)
 634       {
 635          png_push_save_buffer(png_ptr);
 636          return;
 637       }
 638
 639       png_push_fill_buffer(png_ptr, chunk_length, 4);
 640       png_ptr->push_length = png_get_uint_32(chunk_length);
 641
 642       png_reset_crc(png_ptr);
 643       png_crc_read(png_ptr, png_ptr->chunk_name, 4);
 644       png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
 645
 646       if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
 647       {
 648          png_ptr->process_mode = PNG_READ_CHUNK_MODE;
 649          if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
 650             png_error(png_ptr, "Not enough compressed data");
 651          return;
 652       }
 653
 654       png_ptr->idat_size = png_ptr->push_length;
 655    }
 656    if (png_ptr->idat_size && png_ptr->save_buffer_size)
 657    {
 658       png_size_t save_size;
 659
 660       if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
 661       {
 662          save_size = (png_size_t)png_ptr->idat_size;
 663          /* check for overflow */
 664          if((png_uint_32)save_size != png_ptr->idat_size)
 665             png_error(png_ptr, "save_size overflowed in pngpread");
 666       }
 667       else
 668          save_size = png_ptr->save_buffer_size;
 669
 670       png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
 671       if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
 672          png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
 673       png_ptr->idat_size -= save_size;
 674       png_ptr->buffer_size -= save_size;
 675       png_ptr->save_buffer_size -= save_size;
 676       png_ptr->save_buffer_ptr += save_size;
 677    }
 678    if (png_ptr->idat_size && png_ptr->current_buffer_size)
 679    {
 680       png_size_t save_size;
 681
 682       if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
 683       {
 684          save_size = (png_size_t)png_ptr->idat_size;
 685          /* check for overflow */
 686          if((png_uint_32)save_size != png_ptr->idat_size)
 687             png_error(png_ptr, "save_size overflowed in pngpread");
 688       }
 689       else
 690          save_size = png_ptr->current_buffer_size;
 691
 692       png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
 693       if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
 694         png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
 695
 696       png_ptr->idat_size -= save_size;
 697       png_ptr->buffer_size -= save_size;
 698       png_ptr->current_buffer_size -= save_size;
 699       png_ptr->current_buffer_ptr += save_size;
 700    }
 701    if (!png_ptr->idat_size)
 702    {
 703       if (png_ptr->buffer_size < 4)
 704       {
 705          png_push_save_buffer(png_ptr);
 706          return;
 707       }
 708
 709       png_crc_finish(png_ptr, 0);
 710       png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 711       png_ptr->mode |= PNG_AFTER_IDAT;
 712    }
 713 }
 714
 715 void /* PRIVATE */
 716 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
 717    png_size_t buffer_length)
 718 {
 719    int ret;
 720
 721    if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
 722       png_error(png_ptr, "Extra compression data");
 723
 724    png_ptr->zstream.next_in = buffer;
 725    png_ptr->zstream.avail_in = (uInt)buffer_length;
 726    for(;;)
 727    {
 728       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 729       if (ret != Z_OK)
 730       {
 731          if (ret == Z_STREAM_END)
 732          {
 733             if (png_ptr->zstream.avail_in)
 734                png_error(png_ptr, "Extra compressed data");
 735             if (!(png_ptr->zstream.avail_out))
 736             {
 737                png_push_process_row(png_ptr);
 738             }
 739
 740             png_ptr->mode |= PNG_AFTER_IDAT;
 741             png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 742             break;
 743          }
 744          else if (ret == Z_BUF_ERROR)
 745             break;
 746          else
 747             png_error(png_ptr, "Decompression Error");
 748       }
 749       if (!(png_ptr->zstream.avail_out))
 750       {
 751          if ((
 752 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 753              png_ptr->interlaced && png_ptr->pass > 6) ||
 754              (!png_ptr->interlaced &&
 755 #endif
 756              png_ptr->row_number == png_ptr->num_rows-1))
 757          {
 758            if (png_ptr->zstream.avail_in)
 759              png_warning(png_ptr, "Too much data in IDAT chunks");
 760            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 761            break;
 762          }
 763          png_push_process_row(png_ptr);
 764          png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
 765          png_ptr->zstream.next_out = png_ptr->row_buf;
 766       }
 767       else
 768          break;
 769    }
 770 }
 771
 772 void /* PRIVATE */
 773 png_push_process_row(png_structp png_ptr)
 774 {
 775    png_ptr->row_info.color_type = png_ptr->color_type;
 776    png_ptr->row_info.width = png_ptr->iwidth;
 777    png_ptr->row_info.channels = png_ptr->channels;
 778    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 779    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 780
 781    png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
 782       (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
 783
 784    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 785       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 786       (int)(png_ptr->row_buf[0]));
 787
 788    png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
 789       png_ptr->rowbytes + 1);
 790
 791    if (png_ptr->transformations)
 792       png_do_read_transformations(png_ptr);
 793
 794 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 795    /* blow up interlaced rows to full size */
 796    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 797    {
 798       if (png_ptr->pass < 6)
 799 /*       old interface (pre-1.0.9):
 800          png_do_read_interlace(&(png_ptr->row_info),
 801             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 802  */
 803          png_do_read_interlace(png_ptr);
 804
 805     switch (png_ptr->pass)
 806     {
 807          case 0:
 808          {
 809             int i;
 810             for (i = 0; i < 8 && png_ptr->pass == 0; i++)
 811             {
 812                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 813                png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
 814             }
 815             if (png_ptr->pass == 2) /* pass 1 might be empty */
 816             {
 817                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 818                {
 819                   png_push_have_row(png_ptr, png_bytep_NULL);
 820                   png_read_push_finish_row(png_ptr);
 821                }
 822             }
 823             if (png_ptr->pass == 4 && png_ptr->height <= 4)
 824             {
 825                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 826                {
 827                   png_push_have_row(png_ptr, png_bytep_NULL);
 828                   png_read_push_finish_row(png_ptr);
 829                }
 830             }
 831             if (png_ptr->pass == 6 && png_ptr->height <= 4)
 832             {
 833                 png_push_have_row(png_ptr, png_bytep_NULL);
 834                 png_read_push_finish_row(png_ptr);
 835             }
 836             break;
 837          }
 838          case 1:
 839          {
 840             int i;
 841             for (i = 0; i < 8 && png_ptr->pass == 1; i++)
 842             {
 843                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 844                png_read_push_finish_row(png_ptr);
 845             }
 846             if (png_ptr->pass == 2) /* skip top 4 generated rows */
 847             {
 848                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 849                {
 850                   png_push_have_row(png_ptr, png_bytep_NULL);
 851                   png_read_push_finish_row(png_ptr);
 852                }
 853             }
 854             break;
 855          }
 856          case 2:
 857          {
 858             int i;
 859             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 860             {
 861                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 862                png_read_push_finish_row(png_ptr);
 863             }
 864             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 865             {
 866                png_push_have_row(png_ptr, png_bytep_NULL);
 867                png_read_push_finish_row(png_ptr);
 868             }
 869             if (png_ptr->pass == 4) /* pass 3 might be empty */
 870             {
 871                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 872                {
 873                   png_push_have_row(png_ptr, png_bytep_NULL);
 874                   png_read_push_finish_row(png_ptr);
 875                }
 876             }
 877             break;
 878          }
 879          case 3:
 880          {
 881             int i;
 882             for (i = 0; i < 4 && png_ptr->pass == 3; i++)
 883             {
 884                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 885                png_read_push_finish_row(png_ptr);
 886             }
 887             if (png_ptr->pass == 4) /* skip top two generated rows */
 888             {
 889                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 890                {
 891                   png_push_have_row(png_ptr, png_bytep_NULL);
 892                   png_read_push_finish_row(png_ptr);
 893                }
 894             }
 895             break;
 896          }
 897          case 4:
 898          {
 899             int i;
 900             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 901             {
 902                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 903                png_read_push_finish_row(png_ptr);
 904             }
 905             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 906             {
 907                png_push_have_row(png_ptr, png_bytep_NULL);
 908                png_read_push_finish_row(png_ptr);
 909             }
 910             if (png_ptr->pass == 6) /* pass 5 might be empty */
 911             {
 912                png_push_have_row(png_ptr, png_bytep_NULL);
 913                png_read_push_finish_row(png_ptr);
 914             }
 915             break;
 916          }
 917          case 5:
 918          {
 919             int i;
 920             for (i = 0; i < 2 && png_ptr->pass == 5; i++)
 921             {
 922                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 923                png_read_push_finish_row(png_ptr);
 924             }
 925             if (png_ptr->pass == 6) /* skip top generated row */
 926             {
 927                png_push_have_row(png_ptr, png_bytep_NULL);
 928                png_read_push_finish_row(png_ptr);
 929             }
 930             break;
 931          }
 932          case 6:
 933          {
 934             png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 935             png_read_push_finish_row(png_ptr);
 936             if (png_ptr->pass != 6)
 937                break;
 938             png_push_have_row(png_ptr, png_bytep_NULL);
 939             png_read_push_finish_row(png_ptr);
 940          }
 941       }
 942    }
 943    else
 944 #endif
 945    {
 946       png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 947       png_read_push_finish_row(png_ptr);
 948    }
 949 }
 950
 951 void /* PRIVATE */
 952 png_read_push_finish_row(png_structp png_ptr)
 953 {
 954 #ifdef PNG_USE_LOCAL_ARRAYS
 955    /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 956
 957    /* start of interlace block */
 958    const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 959
 960    /* offset to next interlace block */
 961    const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 962
 963    /* start of interlace block in the y direction */
 964    const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 965
 966    /* offset to next interlace block in the y direction */
 967    const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 968
 969    /* Width of interlace block.  This is not currently used - if you need
 970     * it, uncomment it here and in png.h
 971    const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
 972    */
 973
 974    /* Height of interlace block.  This is not currently used - if you need
 975     * it, uncomment it here and in png.h
 976    const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
 977    */
 978 #endif
 979
 980    png_ptr->row_number++;
 981    if (png_ptr->row_number < png_ptr->num_rows)
 982       return;
 983
 984    if (png_ptr->interlaced)
 985    {
 986       png_ptr->row_number = 0;
 987       png_memset_check(png_ptr, png_ptr->prev_row, 0,
 988          png_ptr->rowbytes + 1);
 989       do
 990       {
 991          png_ptr->pass++;
 992          if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
 993              (png_ptr->pass == 3 && png_ptr->width < 3) ||
 994              (png_ptr->pass == 5 && png_ptr->width < 2))
 995            png_ptr->pass++;
 996
 997          if (png_ptr->pass > 7)
 998             png_ptr->pass--;
 999          if (png_ptr->pass >= 7)
1000             break;
1001
1002          png_ptr->iwidth = (png_ptr->width +
1003             png_pass_inc[png_ptr->pass] - 1 -
1004             png_pass_start[png_ptr->pass]) /
1005             png_pass_inc[png_ptr->pass];
1006
1007          png_ptr->irowbytes = ((png_ptr->iwidth *
1008             png_ptr->pixel_depth + 7) >> 3) + 1;
1009
1010          if (png_ptr->transformations & PNG_INTERLACE)
1011             break;
1012
1013          png_ptr->num_rows = (png_ptr->height +
1014             png_pass_yinc[png_ptr->pass] - 1 -
1015             png_pass_ystart[png_ptr->pass]) /
1016             png_pass_yinc[png_ptr->pass];
1017
1018       } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1019    }
1020 }
1021
1022 #if defined(PNG_READ_tEXt_SUPPORTED)
1023 void /* PRIVATE */
1024 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1025    length)
1026 {
1027    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1028       {
1029          png_error(png_ptr, "Out of place tEXt");
1030          /* to quiet some compiler warnings */
1031          if(info_ptr == NULL) return;
1032       }
1033
1034 #ifdef PNG_MAX_MALLOC_64K
1035    png_ptr->skip_length = 0;  /* This may not be necessary */
1036
1037    if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1038    {
1039       png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1040       png_ptr->skip_length = length - (png_uint_32)65535L;
1041       length = (png_uint_32)65535L;
1042    }
1043 #endif
1044
1045    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1046          (png_uint_32)(length+1));
1047    png_ptr->current_text[length] = '\0';
1048    png_ptr->current_text_ptr = png_ptr->current_text;
1049    png_ptr->current_text_size = (png_size_t)length;
1050    png_ptr->current_text_left = (png_size_t)length;
1051    png_ptr->process_mode = PNG_READ_tEXt_MODE;
1052 }
1053
1054 void /* PRIVATE */
1055 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1056 {
1057    if (png_ptr->buffer_size && png_ptr->current_text_left)
1058    {
1059       png_size_t text_size;
1060
1061       if (png_ptr->buffer_size < png_ptr->current_text_left)
1062          text_size = png_ptr->buffer_size;
1063       else
1064          text_size = png_ptr->current_text_left;
1065       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1066       png_ptr->current_text_left -= text_size;
1067       png_ptr->current_text_ptr += text_size;
1068    }
1069    if (!(png_ptr->current_text_left))
1070    {
1071       png_textp text_ptr;
1072       png_charp text;
1073       png_charp key;
1074       int ret;
1075
1076       if (png_ptr->buffer_size < 4)
1077       {
1078          png_push_save_buffer(png_ptr);
1079          return;
1080       }
1081
1082       png_push_crc_finish(png_ptr);
1083
1084 #if defined(PNG_MAX_MALLOC_64K)
1085       if (png_ptr->skip_length)
1086          return;
1087 #endif
1088
1089       key = png_ptr->current_text;
1090
1091       for (text = key; *text; text++)
1092          /* empty loop */ ;
1093
1094       if (text != key + png_ptr->current_text_size)
1095          text++;
1096
1097       text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1098       text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1099       text_ptr->key = key;
1100 #ifdef PNG_iTXt_SUPPORTED
1101       text_ptr->lang = NULL;
1102       text_ptr->lang_key = NULL;
1103 #endif
1104       text_ptr->text = text;
1105
1106       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1107
1108       png_free(png_ptr, key);
1109       png_free(png_ptr, text_ptr);
1110       png_ptr->current_text = NULL;
1111
1112       if (ret)
1113         png_warning(png_ptr, "Insufficient memory to store text chunk.");
1114    }
1115 }
1116 #endif
1117
1118 #if defined(PNG_READ_zTXt_SUPPORTED)
1119 void /* PRIVATE */
1120 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1121    length)
1122 {
1123    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1124       {
1125          png_error(png_ptr, "Out of place zTXt");
1126          /* to quiet some compiler warnings */
1127          if(info_ptr == NULL) return;
1128       }
1129
1130 #ifdef PNG_MAX_MALLOC_64K
1131    /* We can't handle zTXt chunks > 64K, since we don't have enough space
1132     * to be able to store the uncompressed data.  Actually, the threshold
1133     * is probably around 32K, but it isn't as definite as 64K is.
1134     */
1135    if (length > (png_uint_32)65535L)
1136    {
1137       png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1138       png_push_crc_skip(png_ptr, length);
1139       return;
1140    }
1141 #endif
1142
1143    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1144        (png_uint_32)(length+1));
1145    png_ptr->current_text[length] = '\0';
1146    png_ptr->current_text_ptr = png_ptr->current_text;
1147    png_ptr->current_text_size = (png_size_t)length;
1148    png_ptr->current_text_left = (png_size_t)length;
1149    png_ptr->process_mode = PNG_READ_zTXt_MODE;
1150 }
1151
1152 void /* PRIVATE */
1153 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1154 {
1155    if (png_ptr->buffer_size && png_ptr->current_text_left)
1156    {
1157       png_size_t text_size;
1158
1159       if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1160          text_size = png_ptr->buffer_size;
1161       else
1162          text_size = png_ptr->current_text_left;
1163       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1164       png_ptr->current_text_left -= text_size;
1165       png_ptr->current_text_ptr += text_size;
1166    }
1167    if (!(png_ptr->current_text_left))
1168    {
1169       png_textp text_ptr;
1170       png_charp text;
1171       png_charp key;
1172       int ret;
1173       png_size_t text_size, key_size;
1174
1175       if (png_ptr->buffer_size < 4)
1176       {
1177          png_push_save_buffer(png_ptr);
1178          return;
1179       }
1180
1181       png_push_crc_finish(png_ptr);
1182
1183       key = png_ptr->current_text;
1184
1185       for (text = key; *text; text++)
1186          /* empty loop */ ;
1187
1188       /* zTXt can't have zero text */
1189       if (text == key + png_ptr->current_text_size)
1190       {
1191          png_ptr->current_text = NULL;
1192          png_free(png_ptr, key);
1193          return;
1194       }
1195
1196       text++;
1197
1198       if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
1199       {
1200          png_ptr->current_text = NULL;
1201          png_free(png_ptr, key);
1202          return;
1203       }
1204
1205       text++;
1206
1207       png_ptr->zstream.next_in = (png_bytep )text;
1208       png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1209          (text - key));
1210       png_ptr->zstream.next_out = png_ptr->zbuf;
1211       png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1212
1213       key_size = text - key;
1214       text_size = 0;
1215       text = NULL;
1216       ret = Z_STREAM_END;
1217
1218       while (png_ptr->zstream.avail_in)
1219       {
1220          ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1221          if (ret != Z_OK && ret != Z_STREAM_END)
1222          {
1223             inflateReset(&png_ptr->zstream);
1224             png_ptr->zstream.avail_in = 0;
1225             png_ptr->current_text = NULL;
1226             png_free(png_ptr, key);
1227             png_free(png_ptr, text);
1228             return;
1229          }
1230          if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1231          {
1232             if (text == NULL)
1233             {
1234                text = (png_charp)png_malloc(png_ptr,
1235                   (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1236                      + key_size + 1));
1237                png_memcpy(text + key_size, png_ptr->zbuf,
1238                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1239                png_memcpy(text, key, key_size);
1240                text_size = key_size + png_ptr->zbuf_size -
1241                   png_ptr->zstream.avail_out;
1242                *(text + text_size) = '\0';
1243             }
1244             else
1245             {
1246                png_charp tmp;
1247
1248                tmp = text;
1249                text = (png_charp)png_malloc(png_ptr, text_size +
1250                   (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1251                    + 1));
1252                png_memcpy(text, tmp, text_size);
1253                png_free(png_ptr, tmp);
1254                png_memcpy(text + text_size, png_ptr->zbuf,
1255                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1256                text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1257                *(text + text_size) = '\0';
1258             }
1259             if (ret != Z_STREAM_END)
1260             {
1261                png_ptr->zstream.next_out = png_ptr->zbuf;
1262                png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1263             }
1264          }
1265          else
1266          {
1267             break;
1268          }
1269
1270          if (ret == Z_STREAM_END)
1271             break;
1272       }
1273
1274       inflateReset(&png_ptr->zstream);
1275       png_ptr->zstream.avail_in = 0;
1276
1277       if (ret != Z_STREAM_END)
1278       {
1279          png_ptr->current_text = NULL;
1280          png_free(png_ptr, key);
1281          png_free(png_ptr, text);
1282          return;
1283       }
1284
1285       png_ptr->current_text = NULL;
1286       png_free(png_ptr, key);
1287       key = text;
1288       text += key_size;
1289
1290       text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1291       text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1292       text_ptr->key = key;
1293 #ifdef PNG_iTXt_SUPPORTED
1294       text_ptr->lang = NULL;
1295       text_ptr->lang_key = NULL;
1296 #endif
1297       text_ptr->text = text;
1298
1299       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1300
1301       png_free(png_ptr, key);
1302       png_free(png_ptr, text_ptr);
1303
1304       if (ret)
1305         png_warning(png_ptr, "Insufficient memory to store text chunk.");
1306    }
1307 }
1308 #endif
1309
1310 #if defined(PNG_READ_iTXt_SUPPORTED)
1311 void /* PRIVATE */
1312 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1313    length)
1314 {
1315    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1316       {
1317          png_error(png_ptr, "Out of place iTXt");
1318          /* to quiet some compiler warnings */
1319          if(info_ptr == NULL) return;
1320       }
1321
1322 #ifdef PNG_MAX_MALLOC_64K
1323    png_ptr->skip_length = 0;  /* This may not be necessary */
1324
1325    if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1326    {
1327       png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1328       png_ptr->skip_length = length - (png_uint_32)65535L;
1329       length = (png_uint_32)65535L;
1330    }
1331 #endif
1332
1333    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1334          (png_uint_32)(length+1));
1335    png_ptr->current_text[length] = '\0';
1336    png_ptr->current_text_ptr = png_ptr->current_text;
1337    png_ptr->current_text_size = (png_size_t)length;
1338    png_ptr->current_text_left = (png_size_t)length;
1339    png_ptr->process_mode = PNG_READ_iTXt_MODE;
1340 }
1341
1342 void /* PRIVATE */
1343 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1344 {
1345
1346    if (png_ptr->buffer_size && png_ptr->current_text_left)
1347    {
1348       png_size_t text_size;
1349
1350       if (png_ptr->buffer_size < png_ptr->current_text_left)
1351          text_size = png_ptr->buffer_size;
1352       else
1353          text_size = png_ptr->current_text_left;
1354       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1355       png_ptr->current_text_left -= text_size;
1356       png_ptr->current_text_ptr += text_size;
1357    }
1358    if (!(png_ptr->current_text_left))
1359    {
1360       png_textp text_ptr;
1361       png_charp key;
1362       int comp_flag;
1363       png_charp lang;
1364       png_charp lang_key;
1365       png_charp text;
1366       int ret;
1367
1368       if (png_ptr->buffer_size < 4)
1369       {
1370          png_push_save_buffer(png_ptr);
1371          return;
1372       }
1373
1374       png_push_crc_finish(png_ptr);
1375
1376 #if defined(PNG_MAX_MALLOC_64K)
1377       if (png_ptr->skip_length)
1378          return;
1379 #endif
1380
1381       key = png_ptr->current_text;
1382
1383       for (lang = key; *lang; lang++)
1384          /* empty loop */ ;
1385
1386       if (lang != key + png_ptr->current_text_size)
1387          lang++;
1388
1389       comp_flag = *lang++;
1390       lang++;     /* skip comp_type, always zero */
1391
1392       for (lang_key = lang; *lang_key; lang_key++)
1393          /* empty loop */ ;
1394       lang_key++;        /* skip NUL separator */
1395
1396       for (text = lang_key; *text; text++)
1397          /* empty loop */ ;
1398
1399       if (text != key + png_ptr->current_text_size)
1400          text++;
1401
1402       text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1403       text_ptr->compression = comp_flag + 2;
1404       text_ptr->key = key;
1405       text_ptr->lang = lang;
1406       text_ptr->lang_key = lang_key;
1407       text_ptr->text = text;
1408       text_ptr->text_length = 0;
1409       text_ptr->itxt_length = png_strlen(text);
1410
1411       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1412
1413       png_ptr->current_text = NULL;
1414
1415       png_free(png_ptr, text_ptr);
1416       if (ret)
1417         png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
1418    }
1419 }
1420 #endif
1421
1422 /* This function is called when we haven't found a handler for this
1423  * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
1424  * name or a critical chunk), the chunk is (currently) silently ignored.
1425  */
1426 void /* PRIVATE */
1427 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1428    length)
1429 {
1430    png_uint_32 skip=0;
1431    png_check_chunk_name(png_ptr, png_ptr->chunk_name);
1432
1433    if (!(png_ptr->chunk_name[0] & 0x20))
1434    {
1435 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1436       if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1437            HANDLE_CHUNK_ALWAYS
1438 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1439            && png_ptr->read_user_chunk_fn == NULL
1440 #endif
1441          )
1442 #endif
1443          png_chunk_error(png_ptr, "unknown critical chunk");
1444
1445       /* to quiet compiler warnings about unused info_ptr */
1446       if (info_ptr == NULL)
1447          return;
1448    }
1449
1450 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1451    if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1452    {
1453        png_unknown_chunk chunk;
1454
1455 #ifdef PNG_MAX_MALLOC_64K
1456        if (length > (png_uint_32)65535L)
1457        {
1458            png_warning(png_ptr, "unknown chunk too large to fit in memory");
1459            skip = length - (png_uint_32)65535L;
1460            length = (png_uint_32)65535L;
1461        }
1462 #endif
1463
1464        png_strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
1465        chunk.data = (png_bytep)png_malloc(png_ptr, length);
1466        png_crc_read(png_ptr, chunk.data, length);
1467        chunk.size = length;
1468 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1469        if(png_ptr->read_user_chunk_fn != NULL)
1470        {
1471           /* callback to user unknown chunk handler */
1472           if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
1473           {
1474              if (!(png_ptr->chunk_name[0] & 0x20))
1475                 if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1476                      HANDLE_CHUNK_ALWAYS)
1477                    png_chunk_error(png_ptr, "unknown critical chunk");
1478           }
1479              png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1480        }
1481        else
1482 #endif
1483           png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1484        png_free(png_ptr, chunk.data);
1485    }
1486    else
1487 #endif
1488       skip=length;
1489    png_push_crc_skip(png_ptr, skip);
1490 }
1491
1492 void /* PRIVATE */
1493 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1494 {
1495    if (png_ptr->info_fn != NULL)
1496       (*(png_ptr->info_fn))(png_ptr, info_ptr);
1497 }
1498
1499 void /* PRIVATE */
1500 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1501 {
1502    if (png_ptr->end_fn != NULL)
1503       (*(png_ptr->end_fn))(png_ptr, info_ptr);
1504 }
1505
1506 void /* PRIVATE */
1507 png_push_have_row(png_structp png_ptr, png_bytep row)
1508 {
1509    if (png_ptr->row_fn != NULL)
1510       (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1511          (int)png_ptr->pass);
1512 }
1513
1514 void PNGAPI
1515 png_progressive_combine_row (png_structp png_ptr,
1516    png_bytep old_row, png_bytep new_row)
1517 {
1518 #ifdef PNG_USE_LOCAL_ARRAYS
1519    const int FARDATA png_pass_dsp_mask[7] =
1520       {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1521 #endif
1522    if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
1523       png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1524 }
1525
1526 void PNGAPI
1527 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1528    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1529    png_progressive_end_ptr end_fn)
1530 {
1531    png_ptr->info_fn = info_fn;
1532    png_ptr->row_fn = row_fn;
1533    png_ptr->end_fn = end_fn;
1534
1535    png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1536 }
1537
1538 png_voidp PNGAPI
1539 png_get_progressive_ptr(png_structp png_ptr)
1540 {
1541    return png_ptr->io_ptr;
1542 }
1543 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */