src/png/pngpread.c

   1
   2 /* pngpread.c - read a png file in push mode
   3  *
   4  * libpng 1.2.4 - July 8, 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       png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
 672
 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       png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
 694
 695       png_ptr->idat_size -= save_size;
 696       png_ptr->buffer_size -= save_size;
 697       png_ptr->current_buffer_size -= save_size;
 698       png_ptr->current_buffer_ptr += save_size;
 699    }
 700    if (!png_ptr->idat_size)
 701    {
 702       if (png_ptr->buffer_size < 4)
 703       {
 704          png_push_save_buffer(png_ptr);
 705          return;
 706       }
 707
 708       png_crc_finish(png_ptr, 0);
 709       png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 710    }
 711 }
 712
 713 void /* PRIVATE */
 714 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
 715    png_size_t buffer_length)
 716 {
 717    int ret;
 718
 719    if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
 720       png_error(png_ptr, "Extra compression data");
 721
 722    png_ptr->zstream.next_in = buffer;
 723    png_ptr->zstream.avail_in = (uInt)buffer_length;
 724    for(;;)
 725    {
 726       ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
 727       if (ret != Z_OK)
 728       {
 729          if (ret == Z_STREAM_END)
 730          {
 731             if (png_ptr->zstream.avail_in)
 732                png_error(png_ptr, "Extra compressed data");
 733             if (!(png_ptr->zstream.avail_out))
 734             {
 735                png_push_process_row(png_ptr);
 736             }
 737
 738             png_ptr->mode |= PNG_AFTER_IDAT;
 739             png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
 740             break;
 741          }
 742          else if (ret == Z_BUF_ERROR)
 743             break;
 744          else
 745             png_error(png_ptr, "Decompression Error");
 746       }
 747       if (!(png_ptr->zstream.avail_out))
 748       {
 749          if ((
 750 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 751              png_ptr->interlaced && png_ptr->pass > 6) ||
 752              (!png_ptr->interlaced &&
 753 #endif
 754              png_ptr->row_number == png_ptr->num_rows-1))
 755            png_error(png_ptr, "Too much data in IDAT chunks");
 756          png_push_process_row(png_ptr);
 757          png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
 758          png_ptr->zstream.next_out = png_ptr->row_buf;
 759       }
 760       else
 761          break;
 762    }
 763 }
 764
 765 void /* PRIVATE */
 766 png_push_process_row(png_structp png_ptr)
 767 {
 768    png_ptr->row_info.color_type = png_ptr->color_type;
 769    png_ptr->row_info.width = png_ptr->iwidth;
 770    png_ptr->row_info.channels = png_ptr->channels;
 771    png_ptr->row_info.bit_depth = png_ptr->bit_depth;
 772    png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
 773
 774    png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
 775       (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
 776
 777    png_read_filter_row(png_ptr, &(png_ptr->row_info),
 778       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
 779       (int)(png_ptr->row_buf[0]));
 780
 781    png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
 782       png_ptr->rowbytes + 1);
 783
 784    if (png_ptr->transformations)
 785       png_do_read_transformations(png_ptr);
 786
 787 #if defined(PNG_READ_INTERLACING_SUPPORTED)
 788    /* blow up interlaced rows to full size */
 789    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
 790    {
 791       if (png_ptr->pass < 6)
 792 /*       old interface (pre-1.0.9):
 793          png_do_read_interlace(&(png_ptr->row_info),
 794             png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
 795  */
 796          png_do_read_interlace(png_ptr);
 797
 798     switch (png_ptr->pass)
 799     {
 800          case 0:
 801          {
 802             int i;
 803             for (i = 0; i < 8 && png_ptr->pass == 0; i++)
 804             {
 805                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 806                png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
 807             }
 808             if (png_ptr->pass == 2) /* pass 1 might be empty */
 809             {
 810                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 811                {
 812                   png_push_have_row(png_ptr, png_bytep_NULL);
 813                   png_read_push_finish_row(png_ptr);
 814                }
 815             }
 816             if (png_ptr->pass == 4 && png_ptr->height <= 4)
 817             {
 818                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 819                {
 820                   png_push_have_row(png_ptr, png_bytep_NULL);
 821                   png_read_push_finish_row(png_ptr);
 822                }
 823             }
 824             if (png_ptr->pass == 6 && png_ptr->height <= 4)
 825             {
 826                 png_push_have_row(png_ptr, png_bytep_NULL);
 827                 png_read_push_finish_row(png_ptr);
 828             }
 829             break;
 830          }
 831          case 1:
 832          {
 833             int i;
 834             for (i = 0; i < 8 && png_ptr->pass == 1; i++)
 835             {
 836                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 837                png_read_push_finish_row(png_ptr);
 838             }
 839             if (png_ptr->pass == 2) /* skip top 4 generated rows */
 840             {
 841                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 842                {
 843                   png_push_have_row(png_ptr, png_bytep_NULL);
 844                   png_read_push_finish_row(png_ptr);
 845                }
 846             }
 847             break;
 848          }
 849          case 2:
 850          {
 851             int i;
 852             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 853             {
 854                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 855                png_read_push_finish_row(png_ptr);
 856             }
 857             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
 858             {
 859                png_push_have_row(png_ptr, png_bytep_NULL);
 860                png_read_push_finish_row(png_ptr);
 861             }
 862             if (png_ptr->pass == 4) /* pass 3 might be empty */
 863             {
 864                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 865                {
 866                   png_push_have_row(png_ptr, png_bytep_NULL);
 867                   png_read_push_finish_row(png_ptr);
 868                }
 869             }
 870             break;
 871          }
 872          case 3:
 873          {
 874             int i;
 875             for (i = 0; i < 4 && png_ptr->pass == 3; i++)
 876             {
 877                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 878                png_read_push_finish_row(png_ptr);
 879             }
 880             if (png_ptr->pass == 4) /* skip top two generated rows */
 881             {
 882                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 883                {
 884                   png_push_have_row(png_ptr, png_bytep_NULL);
 885                   png_read_push_finish_row(png_ptr);
 886                }
 887             }
 888             break;
 889          }
 890          case 4:
 891          {
 892             int i;
 893             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 894             {
 895                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 896                png_read_push_finish_row(png_ptr);
 897             }
 898             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
 899             {
 900                png_push_have_row(png_ptr, png_bytep_NULL);
 901                png_read_push_finish_row(png_ptr);
 902             }
 903             if (png_ptr->pass == 6) /* pass 5 might be empty */
 904             {
 905                png_push_have_row(png_ptr, png_bytep_NULL);
 906                png_read_push_finish_row(png_ptr);
 907             }
 908             break;
 909          }
 910          case 5:
 911          {
 912             int i;
 913             for (i = 0; i < 2 && png_ptr->pass == 5; i++)
 914             {
 915                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 916                png_read_push_finish_row(png_ptr);
 917             }
 918             if (png_ptr->pass == 6) /* skip top generated row */
 919             {
 920                png_push_have_row(png_ptr, png_bytep_NULL);
 921                png_read_push_finish_row(png_ptr);
 922             }
 923             break;
 924          }
 925          case 6:
 926          {
 927             png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 928             png_read_push_finish_row(png_ptr);
 929             if (png_ptr->pass != 6)
 930                break;
 931             png_push_have_row(png_ptr, png_bytep_NULL);
 932             png_read_push_finish_row(png_ptr);
 933          }
 934       }
 935    }
 936    else
 937 #endif
 938    {
 939       png_push_have_row(png_ptr, png_ptr->row_buf + 1);
 940       png_read_push_finish_row(png_ptr);
 941    }
 942 }
 943
 944 void /* PRIVATE */
 945 png_read_push_finish_row(png_structp png_ptr)
 946 {
 947 #ifdef PNG_USE_LOCAL_ARRAYS
 948    /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 949
 950    /* start of interlace block */
 951    const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 952
 953    /* offset to next interlace block */
 954    const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 955
 956    /* start of interlace block in the y direction */
 957    const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 958
 959    /* offset to next interlace block in the y direction */
 960    const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 961
 962    /* Width of interlace block.  This is not currently used - if you need
 963     * it, uncomment it here and in png.h
 964    const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
 965    */
 966
 967    /* Height of interlace block.  This is not currently used - if you need
 968     * it, uncomment it here and in png.h
 969    const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
 970    */
 971 #endif
 972
 973    png_ptr->row_number++;
 974    if (png_ptr->row_number < png_ptr->num_rows)
 975       return;
 976
 977    if (png_ptr->interlaced)
 978    {
 979       png_ptr->row_number = 0;
 980       png_memset_check(png_ptr, png_ptr->prev_row, 0,
 981          png_ptr->rowbytes + 1);
 982       do
 983       {
 984          png_ptr->pass++;
 985          if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
 986              (png_ptr->pass == 3 && png_ptr->width < 3) ||
 987              (png_ptr->pass == 5 && png_ptr->width < 2))
 988            png_ptr->pass++;
 989
 990          if (png_ptr->pass >= 7)
 991             break;
 992
 993          png_ptr->iwidth = (png_ptr->width +
 994             png_pass_inc[png_ptr->pass] - 1 -
 995             png_pass_start[png_ptr->pass]) /
 996             png_pass_inc[png_ptr->pass];
 997
 998          png_ptr->irowbytes = ((png_ptr->iwidth *
 999             png_ptr->pixel_depth + 7) >> 3) + 1;
1000
1001          if (png_ptr->transformations & PNG_INTERLACE)
1002             break;
1003
1004          png_ptr->num_rows = (png_ptr->height +
1005             png_pass_yinc[png_ptr->pass] - 1 -
1006             png_pass_ystart[png_ptr->pass]) /
1007             png_pass_yinc[png_ptr->pass];
1008
1009       } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1010    }
1011 }
1012
1013 #if defined(PNG_READ_tEXt_SUPPORTED)
1014 void /* PRIVATE */
1015 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1016    length)
1017 {
1018    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1019       {
1020          png_error(png_ptr, "Out of place tEXt");
1021          /* to quiet some compiler warnings */
1022          if(info_ptr == NULL) return;
1023       }
1024
1025 #ifdef PNG_MAX_MALLOC_64K
1026    png_ptr->skip_length = 0;  /* This may not be necessary */
1027
1028    if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1029    {
1030       png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1031       png_ptr->skip_length = length - (png_uint_32)65535L;
1032       length = (png_uint_32)65535L;
1033    }
1034 #endif
1035
1036    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1037          (png_uint_32)(length+1));
1038    png_ptr->current_text[length] = '\0';
1039    png_ptr->current_text_ptr = png_ptr->current_text;
1040    png_ptr->current_text_size = (png_size_t)length;
1041    png_ptr->current_text_left = (png_size_t)length;
1042    png_ptr->process_mode = PNG_READ_tEXt_MODE;
1043 }
1044
1045 void /* PRIVATE */
1046 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1047 {
1048    if (png_ptr->buffer_size && png_ptr->current_text_left)
1049    {
1050       png_size_t text_size;
1051
1052       if (png_ptr->buffer_size < png_ptr->current_text_left)
1053          text_size = png_ptr->buffer_size;
1054       else
1055          text_size = png_ptr->current_text_left;
1056       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1057       png_ptr->current_text_left -= text_size;
1058       png_ptr->current_text_ptr += text_size;
1059    }
1060    if (!(png_ptr->current_text_left))
1061    {
1062       png_textp text_ptr;
1063       png_charp text;
1064       png_charp key;
1065       int ret;
1066
1067       if (png_ptr->buffer_size < 4)
1068       {
1069          png_push_save_buffer(png_ptr);
1070          return;
1071       }
1072
1073       png_push_crc_finish(png_ptr);
1074
1075 #if defined(PNG_MAX_MALLOC_64K)
1076       if (png_ptr->skip_length)
1077          return;
1078 #endif
1079
1080       key = png_ptr->current_text;
1081
1082       for (text = key; *text; text++)
1083          /* empty loop */ ;
1084
1085       if (text != key + png_ptr->current_text_size)
1086          text++;
1087
1088       text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1089       text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1090       text_ptr->key = key;
1091 #ifdef PNG_iTXt_SUPPORTED
1092       text_ptr->lang = NULL;
1093       text_ptr->lang_key = NULL;
1094 #endif
1095       text_ptr->text = text;
1096
1097       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1098
1099       png_free(png_ptr, key);
1100       png_free(png_ptr, text_ptr);
1101       png_ptr->current_text = NULL;
1102
1103       if (ret)
1104         png_warning(png_ptr, "Insufficient memory to store text chunk.");
1105    }
1106 }
1107 #endif
1108
1109 #if defined(PNG_READ_zTXt_SUPPORTED)
1110 void /* PRIVATE */
1111 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1112    length)
1113 {
1114    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1115       {
1116          png_error(png_ptr, "Out of place zTXt");
1117          /* to quiet some compiler warnings */
1118          if(info_ptr == NULL) return;
1119       }
1120
1121 #ifdef PNG_MAX_MALLOC_64K
1122    /* We can't handle zTXt chunks > 64K, since we don't have enough space
1123     * to be able to store the uncompressed data.  Actually, the threshold
1124     * is probably around 32K, but it isn't as definite as 64K is.
1125     */
1126    if (length > (png_uint_32)65535L)
1127    {
1128       png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1129       png_push_crc_skip(png_ptr, length);
1130       return;
1131    }
1132 #endif
1133
1134    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1135        (png_uint_32)(length+1));
1136    png_ptr->current_text[length] = '\0';
1137    png_ptr->current_text_ptr = png_ptr->current_text;
1138    png_ptr->current_text_size = (png_size_t)length;
1139    png_ptr->current_text_left = (png_size_t)length;
1140    png_ptr->process_mode = PNG_READ_zTXt_MODE;
1141 }
1142
1143 void /* PRIVATE */
1144 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1145 {
1146    if (png_ptr->buffer_size && png_ptr->current_text_left)
1147    {
1148       png_size_t text_size;
1149
1150       if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1151          text_size = png_ptr->buffer_size;
1152       else
1153          text_size = png_ptr->current_text_left;
1154       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1155       png_ptr->current_text_left -= text_size;
1156       png_ptr->current_text_ptr += text_size;
1157    }
1158    if (!(png_ptr->current_text_left))
1159    {
1160       png_textp text_ptr;
1161       png_charp text;
1162       png_charp key;
1163       int ret;
1164       png_size_t text_size, key_size;
1165
1166       if (png_ptr->buffer_size < 4)
1167       {
1168          png_push_save_buffer(png_ptr);
1169          return;
1170       }
1171
1172       png_push_crc_finish(png_ptr);
1173
1174       key = png_ptr->current_text;
1175
1176       for (text = key; *text; text++)
1177          /* empty loop */ ;
1178
1179       /* zTXt can't have zero text */
1180       if (text == key + png_ptr->current_text_size)
1181       {
1182          png_ptr->current_text = NULL;
1183          png_free(png_ptr, key);
1184          return;
1185       }
1186
1187       text++;
1188
1189       if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
1190       {
1191          png_ptr->current_text = NULL;
1192          png_free(png_ptr, key);
1193          return;
1194       }
1195
1196       text++;
1197
1198       png_ptr->zstream.next_in = (png_bytep )text;
1199       png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1200          (text - key));
1201       png_ptr->zstream.next_out = png_ptr->zbuf;
1202       png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1203
1204       key_size = text - key;
1205       text_size = 0;
1206       text = NULL;
1207       ret = Z_STREAM_END;
1208
1209       while (png_ptr->zstream.avail_in)
1210       {
1211          ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1212          if (ret != Z_OK && ret != Z_STREAM_END)
1213          {
1214             inflateReset(&png_ptr->zstream);
1215             png_ptr->zstream.avail_in = 0;
1216             png_ptr->current_text = NULL;
1217             png_free(png_ptr, key);
1218             png_free(png_ptr, text);
1219             return;
1220          }
1221          if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1222          {
1223             if (text == NULL)
1224             {
1225                text = (png_charp)png_malloc(png_ptr,
1226                   (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1227                      + key_size + 1));
1228                png_memcpy(text + key_size, png_ptr->zbuf,
1229                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1230                png_memcpy(text, key, key_size);
1231                text_size = key_size + png_ptr->zbuf_size -
1232                   png_ptr->zstream.avail_out;
1233                *(text + text_size) = '\0';
1234             }
1235             else
1236             {
1237                png_charp tmp;
1238
1239                tmp = text;
1240                text = (png_charp)png_malloc(png_ptr, text_size +
1241                   (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1242                    + 1));
1243                png_memcpy(text, tmp, text_size);
1244                png_free(png_ptr, tmp);
1245                png_memcpy(text + text_size, png_ptr->zbuf,
1246                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1247                text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1248                *(text + text_size) = '\0';
1249             }
1250             if (ret != Z_STREAM_END)
1251             {
1252                png_ptr->zstream.next_out = png_ptr->zbuf;
1253                png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1254             }
1255          }
1256          else
1257          {
1258             break;
1259          }
1260
1261          if (ret == Z_STREAM_END)
1262             break;
1263       }
1264
1265       inflateReset(&png_ptr->zstream);
1266       png_ptr->zstream.avail_in = 0;
1267
1268       if (ret != Z_STREAM_END)
1269       {
1270          png_ptr->current_text = NULL;
1271          png_free(png_ptr, key);
1272          png_free(png_ptr, text);
1273          return;
1274       }
1275
1276       png_ptr->current_text = NULL;
1277       png_free(png_ptr, key);
1278       key = text;
1279       text += key_size;
1280
1281       text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1282       text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
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
1295       if (ret)
1296         png_warning(png_ptr, "Insufficient memory to store text chunk.");
1297    }
1298 }
1299 #endif
1300
1301 #if defined(PNG_READ_iTXt_SUPPORTED)
1302 void /* PRIVATE */
1303 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1304    length)
1305 {
1306    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1307       {
1308          png_error(png_ptr, "Out of place iTXt");
1309          /* to quiet some compiler warnings */
1310          if(info_ptr == NULL) return;
1311       }
1312
1313 #ifdef PNG_MAX_MALLOC_64K
1314    png_ptr->skip_length = 0;  /* This may not be necessary */
1315
1316    if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1317    {
1318       png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1319       png_ptr->skip_length = length - (png_uint_32)65535L;
1320       length = (png_uint_32)65535L;
1321    }
1322 #endif
1323
1324    png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1325          (png_uint_32)(length+1));
1326    png_ptr->current_text[length] = '\0';
1327    png_ptr->current_text_ptr = png_ptr->current_text;
1328    png_ptr->current_text_size = (png_size_t)length;
1329    png_ptr->current_text_left = (png_size_t)length;
1330    png_ptr->process_mode = PNG_READ_iTXt_MODE;
1331 }
1332
1333 void /* PRIVATE */
1334 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1335 {
1336
1337    if (png_ptr->buffer_size && png_ptr->current_text_left)
1338    {
1339       png_size_t text_size;
1340
1341       if (png_ptr->buffer_size < png_ptr->current_text_left)
1342          text_size = png_ptr->buffer_size;
1343       else
1344          text_size = png_ptr->current_text_left;
1345       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1346       png_ptr->current_text_left -= text_size;
1347       png_ptr->current_text_ptr += text_size;
1348    }
1349    if (!(png_ptr->current_text_left))
1350    {
1351       png_textp text_ptr;
1352       png_charp key;
1353       int comp_flag;
1354       png_charp lang;
1355       png_charp lang_key;
1356       png_charp text;
1357       int ret;
1358
1359       if (png_ptr->buffer_size < 4)
1360       {
1361          png_push_save_buffer(png_ptr);
1362          return;
1363       }
1364
1365       png_push_crc_finish(png_ptr);
1366
1367 #if defined(PNG_MAX_MALLOC_64K)
1368       if (png_ptr->skip_length)
1369          return;
1370 #endif
1371
1372       key = png_ptr->current_text;
1373
1374       for (lang = key; *lang; lang++)
1375          /* empty loop */ ;
1376
1377       if (lang != key + png_ptr->current_text_size)
1378          lang++;
1379
1380       comp_flag = *lang++;
1381       lang++;     /* skip comp_type, always zero */
1382
1383       for (lang_key = lang; *lang_key; lang_key++)
1384          /* empty loop */ ;
1385       lang_key++;        /* skip NUL separator */
1386
1387       for (text = lang_key; *text; text++)
1388          /* empty loop */ ;
1389
1390       if (text != key + png_ptr->current_text_size)
1391          text++;
1392
1393       text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1394       text_ptr->compression = comp_flag + 2;
1395       text_ptr->key = key;
1396       text_ptr->lang = lang;
1397       text_ptr->lang_key = lang_key;
1398       text_ptr->text = text;
1399       text_ptr->text_length = 0;
1400       text_ptr->itxt_length = png_strlen(text);
1401
1402       ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1403
1404       png_ptr->current_text = NULL;
1405
1406       png_free(png_ptr, text_ptr);
1407       if (ret)
1408         png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
1409    }
1410 }
1411 #endif
1412
1413 /* This function is called when we haven't found a handler for this
1414  * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
1415  * name or a critical chunk), the chunk is (currently) silently ignored.
1416  */
1417 void /* PRIVATE */
1418 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1419    length)
1420 {
1421    png_uint_32 skip=0;
1422    png_check_chunk_name(png_ptr, png_ptr->chunk_name);
1423
1424    if (!(png_ptr->chunk_name[0] & 0x20))
1425    {
1426 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1427       if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1428            HANDLE_CHUNK_ALWAYS
1429 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1430            && png_ptr->read_user_chunk_fn == NULL
1431 #endif
1432          )
1433 #endif
1434          png_chunk_error(png_ptr, "unknown critical chunk");
1435
1436       /* to quiet compiler warnings about unused info_ptr */
1437       if (info_ptr == NULL)
1438          return;
1439    }
1440
1441 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1442    if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1443    {
1444        png_unknown_chunk chunk;
1445
1446 #ifdef PNG_MAX_MALLOC_64K
1447        if (length > (png_uint_32)65535L)
1448        {
1449            png_warning(png_ptr, "unknown chunk too large to fit in memory");
1450            skip = length - (png_uint_32)65535L;
1451            length = (png_uint_32)65535L;
1452        }
1453 #endif
1454
1455        png_strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
1456        chunk.data = (png_bytep)png_malloc(png_ptr, length);
1457        png_crc_read(png_ptr, chunk.data, length);
1458        chunk.size = length;
1459 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1460        if(png_ptr->read_user_chunk_fn != NULL)
1461        {
1462           /* callback to user unknown chunk handler */
1463           if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
1464           {
1465              if (!(png_ptr->chunk_name[0] & 0x20))
1466                 if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1467                      HANDLE_CHUNK_ALWAYS)
1468                    png_chunk_error(png_ptr, "unknown critical chunk");
1469           }
1470              png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1471        }
1472        else
1473 #endif
1474           png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1475        png_free(png_ptr, chunk.data);
1476    }
1477    else
1478 #endif
1479       skip=length;
1480    png_push_crc_skip(png_ptr, skip);
1481 }
1482
1483 void /* PRIVATE */
1484 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1485 {
1486    if (png_ptr->info_fn != NULL)
1487       (*(png_ptr->info_fn))(png_ptr, info_ptr);
1488 }
1489
1490 void /* PRIVATE */
1491 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1492 {
1493    if (png_ptr->end_fn != NULL)
1494       (*(png_ptr->end_fn))(png_ptr, info_ptr);
1495 }
1496
1497 void /* PRIVATE */
1498 png_push_have_row(png_structp png_ptr, png_bytep row)
1499 {
1500    if (png_ptr->row_fn != NULL)
1501       (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1502          (int)png_ptr->pass);
1503 }
1504
1505 void PNGAPI
1506 png_progressive_combine_row (png_structp png_ptr,
1507    png_bytep old_row, png_bytep new_row)
1508 {
1509 #ifdef PNG_USE_LOCAL_ARRAYS
1510    const int FARDATA png_pass_dsp_mask[7] =
1511       {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1512 #endif
1513    if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
1514       png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1515 }
1516
1517 void PNGAPI
1518 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1519    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1520    png_progressive_end_ptr end_fn)
1521 {
1522    png_ptr->info_fn = info_fn;
1523    png_ptr->row_fn = row_fn;
1524    png_ptr->end_fn = end_fn;
1525
1526    png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1527 }
1528
1529 png_voidp PNGAPI
1530 png_get_progressive_ptr(png_structp png_ptr)
1531 {
1532    return png_ptr->io_ptr;
1533 }
1534 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */