1 2 /* pngpread.c - read a png file in push mode 3 * 4 * Last changed in libpng 1.2.44 [June 26, 2010] 5 * Copyright (c) 1998-2010 Glenn Randers-Pehrson 6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) 7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) 8 * 9 * This code is released under the libpng license. 10 * For conditions of distribution and use, see the disclaimer 11 * and license in png.h 12 */ 13 14 #define PNG_INTERNAL 15 #define PNG_NO_PEDANTIC_WARNINGS 16 #include "png.h" 17 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED 18 19 /* Push model modes */ 20 #define PNG_READ_SIG_MODE 0 21 #define PNG_READ_CHUNK_MODE 1 22 #define PNG_READ_IDAT_MODE 2 23 #define PNG_SKIP_MODE 3 24 #define PNG_READ_tEXt_MODE 4 25 #define PNG_READ_zTXt_MODE 5 26 #define PNG_READ_DONE_MODE 6 27 #define PNG_READ_iTXt_MODE 7 28 #define PNG_ERROR_MODE 8 29 30 void PNGAPI 31 png_process_data(png_structp png_ptr, png_infop info_ptr, 32 png_bytep buffer, png_size_t buffer_size) 33 { 34 if (png_ptr == NULL || info_ptr == NULL) 35 return; 36 37 png_push_restore_buffer(png_ptr, buffer, buffer_size); 38 39 while (png_ptr->buffer_size) 40 { 41 png_process_some_data(png_ptr, info_ptr); 42 } 43 } 44 45 /* What we do with the incoming data depends on what we were previously 46 * doing before we ran out of data... 47 */ 48 void /* PRIVATE */ 49 png_process_some_data(png_structp png_ptr, png_infop info_ptr) 50 { 51 if (png_ptr == NULL) 52 return; 53 54 switch (png_ptr->process_mode) 55 { 56 case PNG_READ_SIG_MODE: 57 { 58 png_push_read_sig(png_ptr, info_ptr); 59 break; 60 } 61 62 case PNG_READ_CHUNK_MODE: 63 { 64 png_push_read_chunk(png_ptr, info_ptr); 65 break; 66 } 67 68 case PNG_READ_IDAT_MODE: 69 { 70 png_push_read_IDAT(png_ptr); 71 break; 72 } 73 74 #ifdef PNG_READ_tEXt_SUPPORTED 75 case PNG_READ_tEXt_MODE: 76 { 77 png_push_read_tEXt(png_ptr, info_ptr); 78 break; 79 } 80 81 #endif 82 #ifdef PNG_READ_zTXt_SUPPORTED 83 case PNG_READ_zTXt_MODE: 84 { 85 png_push_read_zTXt(png_ptr, info_ptr); 86 break; 87 } 88 89 #endif 90 #ifdef PNG_READ_iTXt_SUPPORTED 91 case PNG_READ_iTXt_MODE: 92 { 93 png_push_read_iTXt(png_ptr, info_ptr); 94 break; 95 } 96 97 #endif 98 case PNG_SKIP_MODE: 99 { 100 png_push_crc_finish(png_ptr); 101 break; 102 } 103 104 default: 105 { 106 png_ptr->buffer_size = 0; 107 break; 108 } 109 } 110 } 111 112 /* Read any remaining signature bytes from the stream and compare them with 113 * the correct PNG signature. It is possible that this routine is called 114 * with bytes already read from the signature, either because they have been 115 * checked by the calling application, or because of multiple calls to this 116 * routine. 117 */ 118 void /* PRIVATE */ 119 png_push_read_sig(png_structp png_ptr, png_infop info_ptr) 120 { 121 png_size_t num_checked = png_ptr->sig_bytes, 122 num_to_check = 8 - num_checked; 123 124 if (png_ptr->buffer_size < num_to_check) 125 { 126 num_to_check = png_ptr->buffer_size; 127 } 128 129 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), 130 num_to_check); 131 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check); 132 133 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) 134 { 135 if (num_checked < 4 && 136 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) 137 png_error(png_ptr, "Not a PNG file"); 138 else 139 png_error(png_ptr, "PNG file corrupted by ASCII conversion"); 140 } 141 else 142 { 143 if (png_ptr->sig_bytes >= 8) 144 { 145 png_ptr->process_mode = PNG_READ_CHUNK_MODE; 146 } 147 } 148 } 149 150 void /* PRIVATE */ 151 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr) 152 { 153 #ifdef PNG_USE_LOCAL_ARRAYS 154 PNG_CONST PNG_IHDR; 155 PNG_CONST PNG_IDAT; 156 PNG_CONST PNG_IEND; 157 PNG_CONST PNG_PLTE; 158 #ifdef PNG_READ_bKGD_SUPPORTED 159 PNG_CONST PNG_bKGD; 160 #endif 161 #ifdef PNG_READ_cHRM_SUPPORTED 162 PNG_CONST PNG_cHRM; 163 #endif 164 #ifdef PNG_READ_gAMA_SUPPORTED 165 PNG_CONST PNG_gAMA; 166 #endif 167 #ifdef PNG_READ_hIST_SUPPORTED 168 PNG_CONST PNG_hIST; 169 #endif 170 #ifdef PNG_READ_iCCP_SUPPORTED 171 PNG_CONST PNG_iCCP; 172 #endif 173 #ifdef PNG_READ_iTXt_SUPPORTED 174 PNG_CONST PNG_iTXt; 175 #endif 176 #ifdef PNG_READ_oFFs_SUPPORTED 177 PNG_CONST PNG_oFFs; 178 #endif 179 #ifdef PNG_READ_pCAL_SUPPORTED 180 PNG_CONST PNG_pCAL; 181 #endif 182 #ifdef PNG_READ_pHYs_SUPPORTED 183 PNG_CONST PNG_pHYs; 184 #endif 185 #ifdef PNG_READ_sBIT_SUPPORTED 186 PNG_CONST PNG_sBIT; 187 #endif 188 #ifdef PNG_READ_sCAL_SUPPORTED 189 PNG_CONST PNG_sCAL; 190 #endif 191 #ifdef PNG_READ_sRGB_SUPPORTED 192 PNG_CONST PNG_sRGB; 193 #endif 194 #ifdef PNG_READ_sPLT_SUPPORTED 195 PNG_CONST PNG_sPLT; 196 #endif 197 #ifdef PNG_READ_tEXt_SUPPORTED 198 PNG_CONST PNG_tEXt; 199 #endif 200 #ifdef PNG_READ_tIME_SUPPORTED 201 PNG_CONST PNG_tIME; 202 #endif 203 #ifdef PNG_READ_tRNS_SUPPORTED 204 PNG_CONST PNG_tRNS; 205 #endif 206 #ifdef PNG_READ_zTXt_SUPPORTED 207 PNG_CONST PNG_zTXt; 208 #endif 209 #endif /* PNG_USE_LOCAL_ARRAYS */ 210 211 /* First we make sure we have enough data for the 4 byte chunk name 212 * and the 4 byte chunk length before proceeding with decoding the 213 * chunk data. To fully decode each of these chunks, we also make 214 * sure we have enough data in the buffer for the 4 byte CRC at the 215 * end of every chunk (except IDAT, which is handled separately). 216 */ 217 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) 218 { 219 png_byte chunk_length[4]; 220 221 if (png_ptr->buffer_size < 8) 222 { 223 png_push_save_buffer(png_ptr); 224 return; 225 } 226 227 png_push_fill_buffer(png_ptr, chunk_length, 4); 228 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); 229 png_reset_crc(png_ptr); 230 png_crc_read(png_ptr, png_ptr->chunk_name, 4); 231 png_check_chunk_name(png_ptr, png_ptr->chunk_name); 232 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; 233 } 234 235 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) 236 if (png_ptr->mode & PNG_AFTER_IDAT) 237 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT; 238 239 if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4)) 240 { 241 if (png_ptr->push_length != 13) 242 png_error(png_ptr, "Invalid IHDR length"); 243 244 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 245 { 246 png_push_save_buffer(png_ptr); 247 return; 248 } 249 250 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length); 251 } 252 253 else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4)) 254 { 255 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 256 { 257 png_push_save_buffer(png_ptr); 258 return; 259 } 260 261 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length); 262 263 png_ptr->process_mode = PNG_READ_DONE_MODE; 264 png_push_have_end(png_ptr, info_ptr); 265 } 266 267 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 268 else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name)) 269 { 270 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 271 { 272 png_push_save_buffer(png_ptr); 273 return; 274 } 275 276 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) 277 png_ptr->mode |= PNG_HAVE_IDAT; 278 279 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); 280 281 if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4)) 282 png_ptr->mode |= PNG_HAVE_PLTE; 283 284 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) 285 { 286 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 287 png_error(png_ptr, "Missing IHDR before IDAT"); 288 289 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 290 !(png_ptr->mode & PNG_HAVE_PLTE)) 291 png_error(png_ptr, "Missing PLTE before IDAT"); 292 } 293 } 294 295 #endif 296 else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4)) 297 { 298 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 299 { 300 png_push_save_buffer(png_ptr); 301 return; 302 } 303 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length); 304 } 305 306 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) 307 { 308 /* If we reach an IDAT chunk, this means we have read all of the 309 * header chunks, and we can start reading the image (or if this 310 * is called after the image has been read - we have an error). 311 */ 312 313 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 314 png_error(png_ptr, "Missing IHDR before IDAT"); 315 316 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 317 !(png_ptr->mode & PNG_HAVE_PLTE)) 318 png_error(png_ptr, "Missing PLTE before IDAT"); 319 320 if (png_ptr->mode & PNG_HAVE_IDAT) 321 { 322 if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) 323 if (png_ptr->push_length == 0) 324 return; 325 326 if (png_ptr->mode & PNG_AFTER_IDAT) 327 png_error(png_ptr, "Too many IDAT's found"); 328 } 329 330 png_ptr->idat_size = png_ptr->push_length; 331 png_ptr->mode |= PNG_HAVE_IDAT; 332 png_ptr->process_mode = PNG_READ_IDAT_MODE; 333 png_push_have_info(png_ptr, info_ptr); 334 png_ptr->zstream.avail_out = 335 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, 336 png_ptr->iwidth) + 1; 337 png_ptr->zstream.next_out = png_ptr->row_buf; 338 return; 339 } 340 341 #ifdef PNG_READ_gAMA_SUPPORTED 342 else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4)) 343 { 344 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 345 { 346 png_push_save_buffer(png_ptr); 347 return; 348 } 349 350 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length); 351 } 352 353 #endif 354 #ifdef PNG_READ_sBIT_SUPPORTED 355 else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4)) 356 { 357 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 358 { 359 png_push_save_buffer(png_ptr); 360 return; 361 } 362 363 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length); 364 } 365 366 #endif 367 #ifdef PNG_READ_cHRM_SUPPORTED 368 else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4)) 369 { 370 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 371 { 372 png_push_save_buffer(png_ptr); 373 return; 374 } 375 376 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length); 377 } 378 379 #endif 380 #ifdef PNG_READ_sRGB_SUPPORTED 381 else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4)) 382 { 383 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 384 { 385 png_push_save_buffer(png_ptr); 386 return; 387 } 388 389 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length); 390 } 391 392 #endif 393 #ifdef PNG_READ_iCCP_SUPPORTED 394 else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4)) 395 { 396 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 397 { 398 png_push_save_buffer(png_ptr); 399 return; 400 } 401 402 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length); 403 } 404 405 #endif 406 #ifdef PNG_READ_sPLT_SUPPORTED 407 else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4)) 408 { 409 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 410 { 411 png_push_save_buffer(png_ptr); 412 return; 413 } 414 415 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length); 416 } 417 418 #endif 419 #ifdef PNG_READ_tRNS_SUPPORTED 420 else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4)) 421 { 422 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 423 { 424 png_push_save_buffer(png_ptr); 425 return; 426 } 427 428 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length); 429 } 430 431 #endif 432 #ifdef PNG_READ_bKGD_SUPPORTED 433 else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4)) 434 { 435 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 436 { 437 png_push_save_buffer(png_ptr); 438 return; 439 } 440 441 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length); 442 } 443 444 #endif 445 #ifdef PNG_READ_hIST_SUPPORTED 446 else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4)) 447 { 448 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 449 { 450 png_push_save_buffer(png_ptr); 451 return; 452 } 453 454 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length); 455 } 456 457 #endif 458 #ifdef PNG_READ_pHYs_SUPPORTED 459 else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4)) 460 { 461 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 462 { 463 png_push_save_buffer(png_ptr); 464 return; 465 } 466 467 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length); 468 } 469 470 #endif 471 #ifdef PNG_READ_oFFs_SUPPORTED 472 else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4)) 473 { 474 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 475 { 476 png_push_save_buffer(png_ptr); 477 return; 478 } 479 480 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length); 481 } 482 #endif 483 484 #ifdef PNG_READ_pCAL_SUPPORTED 485 else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4)) 486 { 487 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 488 { 489 png_push_save_buffer(png_ptr); 490 return; 491 } 492 493 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length); 494 } 495 496 #endif 497 #ifdef PNG_READ_sCAL_SUPPORTED 498 else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4)) 499 { 500 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 501 { 502 png_push_save_buffer(png_ptr); 503 return; 504 } 505 506 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length); 507 } 508 509 #endif 510 #ifdef PNG_READ_tIME_SUPPORTED 511 else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4)) 512 { 513 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 514 { 515 png_push_save_buffer(png_ptr); 516 return; 517 } 518 519 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length); 520 } 521 522 #endif 523 #ifdef PNG_READ_tEXt_SUPPORTED 524 else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4)) 525 { 526 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 527 { 528 png_push_save_buffer(png_ptr); 529 return; 530 } 531 532 png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length); 533 } 534 535 #endif 536 #ifdef PNG_READ_zTXt_SUPPORTED 537 else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4)) 538 { 539 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 540 { 541 png_push_save_buffer(png_ptr); 542 return; 543 } 544 545 png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length); 546 } 547 548 #endif 549 #ifdef PNG_READ_iTXt_SUPPORTED 550 else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4)) 551 { 552 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 553 { 554 png_push_save_buffer(png_ptr); 555 return; 556 } 557 558 png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length); 559 } 560 561 #endif 562 else 563 { 564 if (png_ptr->push_length + 4 > png_ptr->buffer_size) 565 { 566 png_push_save_buffer(png_ptr); 567 return; 568 } 569 png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); 570 } 571 572 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; 573 } 574 575 void /* PRIVATE */ 576 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip) 577 { 578 png_ptr->process_mode = PNG_SKIP_MODE; 579 png_ptr->skip_length = skip; 580 } 581 582 void /* PRIVATE */ 583 png_push_crc_finish(png_structp png_ptr) 584 { 585 if (png_ptr->skip_length && png_ptr->save_buffer_size) 586 { 587 png_size_t save_size; 588 589 if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size) 590 save_size = (png_size_t)png_ptr->skip_length; 591 else 592 save_size = png_ptr->save_buffer_size; 593 594 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); 595 596 png_ptr->skip_length -= save_size; 597 png_ptr->buffer_size -= save_size; 598 png_ptr->save_buffer_size -= save_size; 599 png_ptr->save_buffer_ptr += save_size; 600 } 601 if (png_ptr->skip_length && png_ptr->current_buffer_size) 602 { 603 png_size_t save_size; 604 605 if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size) 606 save_size = (png_size_t)png_ptr->skip_length; 607 else 608 save_size = png_ptr->current_buffer_size; 609 610 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); 611 612 png_ptr->skip_length -= save_size; 613 png_ptr->buffer_size -= save_size; 614 png_ptr->current_buffer_size -= save_size; 615 png_ptr->current_buffer_ptr += save_size; 616 } 617 if (!png_ptr->skip_length) 618 { 619 if (png_ptr->buffer_size < 4) 620 { 621 png_push_save_buffer(png_ptr); 622 return; 623 } 624 625 png_crc_finish(png_ptr, 0); 626 png_ptr->process_mode = PNG_READ_CHUNK_MODE; 627 } 628 } 629 630 void PNGAPI 631 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length) 632 { 633 png_bytep ptr; 634 635 if (png_ptr == NULL) 636 return; 637 638 ptr = buffer; 639 if (png_ptr->save_buffer_size) 640 { 641 png_size_t save_size; 642 643 if (length < png_ptr->save_buffer_size) 644 save_size = length; 645 else 646 save_size = png_ptr->save_buffer_size; 647 648 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size); 649 length -= save_size; 650 ptr += save_size; 651 png_ptr->buffer_size -= save_size; 652 png_ptr->save_buffer_size -= save_size; 653 png_ptr->save_buffer_ptr += save_size; 654 } 655 if (length && png_ptr->current_buffer_size) 656 { 657 png_size_t save_size; 658 659 if (length < png_ptr->current_buffer_size) 660 save_size = length; 661 662 else 663 save_size = png_ptr->current_buffer_size; 664 665 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size); 666 png_ptr->buffer_size -= save_size; 667 png_ptr->current_buffer_size -= save_size; 668 png_ptr->current_buffer_ptr += save_size; 669 } 670 } 671 672 void /* PRIVATE */ 673 png_push_save_buffer(png_structp png_ptr) 674 { 675 if (png_ptr->save_buffer_size) 676 { 677 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer) 678 { 679 png_size_t i, istop; 680 png_bytep sp; 681 png_bytep dp; 682 683 istop = png_ptr->save_buffer_size; 684 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer; 685 i < istop; i++, sp++, dp++) 686 { 687 *dp = *sp; 688 } 689 } 690 } 691 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size > 692 png_ptr->save_buffer_max) 693 { 694 png_size_t new_max; 695 png_bytep old_buffer; 696 697 if (png_ptr->save_buffer_size > PNG_SIZE_MAX - 698 (png_ptr->current_buffer_size + 256)) 699 { 700 png_error(png_ptr, "Potential overflow of save_buffer"); 701 } 702 703 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256; 704 old_buffer = png_ptr->save_buffer; 705 png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, 706 (png_uint_32)new_max); 707 if (png_ptr->save_buffer == NULL) 708 { 709 png_free(png_ptr, old_buffer); 710 png_error(png_ptr, "Insufficient memory for save_buffer"); 711 } 712 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size); 713 png_free(png_ptr, old_buffer); 714 png_ptr->save_buffer_max = new_max; 715 } 716 if (png_ptr->current_buffer_size) 717 { 718 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size, 719 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size); 720 png_ptr->save_buffer_size += png_ptr->current_buffer_size; 721 png_ptr->current_buffer_size = 0; 722 } 723 png_ptr->save_buffer_ptr = png_ptr->save_buffer; 724 png_ptr->buffer_size = 0; 725 } 726 727 void /* PRIVATE */ 728 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer, 729 png_size_t buffer_length) 730 { 731 png_ptr->current_buffer = buffer; 732 png_ptr->current_buffer_size = buffer_length; 733 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size; 734 png_ptr->current_buffer_ptr = png_ptr->current_buffer; 735 } 736 737 void /* PRIVATE */ 738 png_push_read_IDAT(png_structp png_ptr) 739 { 740 #ifdef PNG_USE_LOCAL_ARRAYS 741 PNG_CONST PNG_IDAT; 742 #endif 743 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) 744 { 745 png_byte chunk_length[4]; 746 747 if (png_ptr->buffer_size < 8) 748 { 749 png_push_save_buffer(png_ptr); 750 return; 751 } 752 753 png_push_fill_buffer(png_ptr, chunk_length, 4); 754 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); 755 png_reset_crc(png_ptr); 756 png_crc_read(png_ptr, png_ptr->chunk_name, 4); 757 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; 758 759 if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) 760 { 761 png_ptr->process_mode = PNG_READ_CHUNK_MODE; 762 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) 763 png_error(png_ptr, "Not enough compressed data"); 764 return; 765 } 766 767 png_ptr->idat_size = png_ptr->push_length; 768 } 769 if (png_ptr->idat_size && png_ptr->save_buffer_size) 770 { 771 png_size_t save_size; 772 773 if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size) 774 { 775 save_size = (png_size_t)png_ptr->idat_size; 776 777 /* Check for overflow */ 778 if ((png_uint_32)save_size != png_ptr->idat_size) 779 png_error(png_ptr, "save_size overflowed in pngpread"); 780 } 781 else 782 save_size = png_ptr->save_buffer_size; 783 784 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); 785 786 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size); 787 788 png_ptr->idat_size -= save_size; 789 png_ptr->buffer_size -= save_size; 790 png_ptr->save_buffer_size -= save_size; 791 png_ptr->save_buffer_ptr += save_size; 792 } 793 if (png_ptr->idat_size && png_ptr->current_buffer_size) 794 { 795 png_size_t save_size; 796 797 if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size) 798 { 799 save_size = (png_size_t)png_ptr->idat_size; 800 801 /* Check for overflow */ 802 if ((png_uint_32)save_size != png_ptr->idat_size) 803 png_error(png_ptr, "save_size overflowed in pngpread"); 804 } 805 else 806 save_size = png_ptr->current_buffer_size; 807 808 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); 809 810 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size); 811 812 png_ptr->idat_size -= save_size; 813 png_ptr->buffer_size -= save_size; 814 png_ptr->current_buffer_size -= save_size; 815 png_ptr->current_buffer_ptr += save_size; 816 } 817 if (!png_ptr->idat_size) 818 { 819 if (png_ptr->buffer_size < 4) 820 { 821 png_push_save_buffer(png_ptr); 822 return; 823 } 824 825 png_crc_finish(png_ptr, 0); 826 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; 827 png_ptr->mode |= PNG_AFTER_IDAT; 828 } 829 } 830 831 void /* PRIVATE */ 832 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer, 833 png_size_t buffer_length) 834 { 835 /* The caller checks for a non-zero buffer length. */ 836 if (!(buffer_length > 0) || buffer == NULL) 837 png_error(png_ptr, "No IDAT data (internal error)"); 838 839 /* This routine must process all the data it has been given 840 * before returning, calling the row callback as required to 841 * handle the uncompressed results. 842 */ 843 png_ptr->zstream.next_in = buffer; 844 png_ptr->zstream.avail_in = (uInt)buffer_length; 845 846 /* Keep going until the decompressed data is all processed 847 * or the stream marked as finished. 848 */ 849 while (png_ptr->zstream.avail_in > 0 && 850 !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) 851 { 852 int ret; 853 854 /* We have data for zlib, but we must check that zlib 855 * has somewhere to put the results. It doesn't matter 856 * if we don't expect any results -- it may be the input 857 * data is just the LZ end code. 858 */ 859 if (!(png_ptr->zstream.avail_out > 0)) 860 { 861 png_ptr->zstream.avail_out = 862 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, 863 png_ptr->iwidth) + 1; 864 png_ptr->zstream.next_out = png_ptr->row_buf; 865 } 866 867 /* Using Z_SYNC_FLUSH here means that an unterminated 868 * LZ stream can still be handled (a stream with a missing 869 * end code), otherwise (Z_NO_FLUSH) a future zlib 870 * implementation might defer output and, therefore, 871 * change the current behavior. (See comments in inflate.c 872 * for why this doesn't happen at present with zlib 1.2.5.) 873 */ 874 ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH); 875 876 /* Check for any failure before proceeding. */ 877 if (ret != Z_OK && ret != Z_STREAM_END) 878 { 879 /* Terminate the decompression. */ 880 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; 881 882 /* This may be a truncated stream (missing or 883 * damaged end code). Treat that as a warning. 884 */ 885 if (png_ptr->row_number >= png_ptr->num_rows || 886 png_ptr->pass > 6) 887 png_warning(png_ptr, "Truncated compressed data in IDAT"); 888 else 889 png_error(png_ptr, "Decompression error in IDAT"); 890 891 /* Skip the check on unprocessed input */ 892 return; 893 } 894 895 /* Did inflate output any data? */ 896 if (png_ptr->zstream.next_out != png_ptr->row_buf) 897 { 898 /* Is this unexpected data after the last row? 899 * If it is, artificially terminate the LZ output 900 * here. 901 */ 902 if (png_ptr->row_number >= png_ptr->num_rows || 903 png_ptr->pass > 6) 904 { 905 /* Extra data. */ 906 png_warning(png_ptr, "Extra compressed data in IDAT"); 907 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; 908 /* Do no more processing; skip the unprocessed 909 * input check below. 910 */ 911 return; 912 } 913 914 /* Do we have a complete row? */ 915 if (png_ptr->zstream.avail_out == 0) 916 png_push_process_row(png_ptr); 917 } 918 919 /* And check for the end of the stream. */ 920 if (ret == Z_STREAM_END) 921 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; 922 } 923 924 /* All the data should have been processed, if anything 925 * is left at this point we have bytes of IDAT data 926 * after the zlib end code. 927 */ 928 if (png_ptr->zstream.avail_in > 0) 929 png_warning(png_ptr, "Extra compression data"); 930 } 931 932 void /* PRIVATE */ 933 png_push_process_row(png_structp png_ptr) 934 { 935 png_ptr->row_info.color_type = png_ptr->color_type; 936 png_ptr->row_info.width = png_ptr->iwidth; 937 png_ptr->row_info.channels = png_ptr->channels; 938 png_ptr->row_info.bit_depth = png_ptr->bit_depth; 939 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth; 940 941 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, 942 png_ptr->row_info.width); 943 944 png_read_filter_row(png_ptr, &(png_ptr->row_info), 945 png_ptr->row_buf + 1, png_ptr->prev_row + 1, 946 (int)(png_ptr->row_buf[0])); 947 948 png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf, 949 png_ptr->rowbytes + 1); 950 951 if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA)) 952 png_do_read_transformations(png_ptr); 953 954 #ifdef PNG_READ_INTERLACING_SUPPORTED 955 /* Blow up interlaced rows to full size */ 956 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) 957 { 958 if (png_ptr->pass < 6) 959 /* old interface (pre-1.0.9): 960 png_do_read_interlace(&(png_ptr->row_info), 961 png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations); 962 */ 963 png_do_read_interlace(png_ptr); 964 965 switch (png_ptr->pass) 966 { 967 case 0: 968 { 969 int i; 970 for (i = 0; i < 8 && png_ptr->pass == 0; i++) 971 { 972 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 973 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */ 974 } 975 976 if (png_ptr->pass == 2) /* Pass 1 might be empty */ 977 { 978 for (i = 0; i < 4 && png_ptr->pass == 2; i++) 979 { 980 png_push_have_row(png_ptr, png_bytep_NULL); 981 png_read_push_finish_row(png_ptr); 982 } 983 } 984 985 if (png_ptr->pass == 4 && png_ptr->height <= 4) 986 { 987 for (i = 0; i < 2 && png_ptr->pass == 4; i++) 988 { 989 png_push_have_row(png_ptr, png_bytep_NULL); 990 png_read_push_finish_row(png_ptr); 991 } 992 } 993 994 if (png_ptr->pass == 6 && png_ptr->height <= 4) 995 { 996 png_push_have_row(png_ptr, png_bytep_NULL); 997 png_read_push_finish_row(png_ptr); 998 } 999 1000 break; 1001 } 1002 1003 case 1: 1004 { 1005 int i; 1006 for (i = 0; i < 8 && png_ptr->pass == 1; i++) 1007 { 1008 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1009 png_read_push_finish_row(png_ptr); 1010 } 1011 1012 if (png_ptr->pass == 2) /* Skip top 4 generated rows */ 1013 { 1014 for (i = 0; i < 4 && png_ptr->pass == 2; i++) 1015 { 1016 png_push_have_row(png_ptr, png_bytep_NULL); 1017 png_read_push_finish_row(png_ptr); 1018 } 1019 } 1020 1021 break; 1022 } 1023 1024 case 2: 1025 { 1026 int i; 1027 1028 for (i = 0; i < 4 && png_ptr->pass == 2; i++) 1029 { 1030 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1031 png_read_push_finish_row(png_ptr); 1032 } 1033 1034 for (i = 0; i < 4 && png_ptr->pass == 2; i++) 1035 { 1036 png_push_have_row(png_ptr, png_bytep_NULL); 1037 png_read_push_finish_row(png_ptr); 1038 } 1039 1040 if (png_ptr->pass == 4) /* Pass 3 might be empty */ 1041 { 1042 for (i = 0; i < 2 && png_ptr->pass == 4; i++) 1043 { 1044 png_push_have_row(png_ptr, png_bytep_NULL); 1045 png_read_push_finish_row(png_ptr); 1046 } 1047 } 1048 1049 break; 1050 } 1051 1052 case 3: 1053 { 1054 int i; 1055 1056 for (i = 0; i < 4 && png_ptr->pass == 3; i++) 1057 { 1058 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1059 png_read_push_finish_row(png_ptr); 1060 } 1061 1062 if (png_ptr->pass == 4) /* Skip top two generated rows */ 1063 { 1064 for (i = 0; i < 2 && png_ptr->pass == 4; i++) 1065 { 1066 png_push_have_row(png_ptr, png_bytep_NULL); 1067 png_read_push_finish_row(png_ptr); 1068 } 1069 } 1070 1071 break; 1072 } 1073 1074 case 4: 1075 { 1076 int i; 1077 1078 for (i = 0; i < 2 && png_ptr->pass == 4; i++) 1079 { 1080 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1081 png_read_push_finish_row(png_ptr); 1082 } 1083 1084 for (i = 0; i < 2 && png_ptr->pass == 4; i++) 1085 { 1086 png_push_have_row(png_ptr, png_bytep_NULL); 1087 png_read_push_finish_row(png_ptr); 1088 } 1089 1090 if (png_ptr->pass == 6) /* Pass 5 might be empty */ 1091 { 1092 png_push_have_row(png_ptr, png_bytep_NULL); 1093 png_read_push_finish_row(png_ptr); 1094 } 1095 1096 break; 1097 } 1098 1099 case 5: 1100 { 1101 int i; 1102 1103 for (i = 0; i < 2 && png_ptr->pass == 5; i++) 1104 { 1105 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1106 png_read_push_finish_row(png_ptr); 1107 } 1108 1109 if (png_ptr->pass == 6) /* Skip top generated row */ 1110 { 1111 png_push_have_row(png_ptr, png_bytep_NULL); 1112 png_read_push_finish_row(png_ptr); 1113 } 1114 1115 break; 1116 } 1117 case 6: 1118 { 1119 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1120 png_read_push_finish_row(png_ptr); 1121 1122 if (png_ptr->pass != 6) 1123 break; 1124 1125 png_push_have_row(png_ptr, png_bytep_NULL); 1126 png_read_push_finish_row(png_ptr); 1127 } 1128 } 1129 } 1130 else 1131 #endif 1132 { 1133 png_push_have_row(png_ptr, png_ptr->row_buf + 1); 1134 png_read_push_finish_row(png_ptr); 1135 } 1136 } 1137 1138 void /* PRIVATE */ 1139 png_read_push_finish_row(png_structp png_ptr) 1140 { 1141 #ifdef PNG_USE_LOCAL_ARRAYS 1142 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 1143 1144 /* Start of interlace block */ 1145 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; 1146 1147 /* Offset to next interlace block */ 1148 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; 1149 1150 /* Start of interlace block in the y direction */ 1151 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; 1152 1153 /* Offset to next interlace block in the y direction */ 1154 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; 1155 1156 /* Height of interlace block. This is not currently used - if you need 1157 * it, uncomment it here and in png.h 1158 PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; 1159 */ 1160 #endif 1161 1162 png_ptr->row_number++; 1163 if (png_ptr->row_number < png_ptr->num_rows) 1164 return; 1165 1166 #ifdef PNG_READ_INTERLACING_SUPPORTED 1167 if (png_ptr->interlaced) 1168 { 1169 png_ptr->row_number = 0; 1170 png_memset_check(png_ptr, png_ptr->prev_row, 0, 1171 png_ptr->rowbytes + 1); 1172 do 1173 { 1174 png_ptr->pass++; 1175 if ((png_ptr->pass == 1 && png_ptr->width < 5) || 1176 (png_ptr->pass == 3 && png_ptr->width < 3) || 1177 (png_ptr->pass == 5 && png_ptr->width < 2)) 1178 png_ptr->pass++; 1179 1180 if (png_ptr->pass > 7) 1181 png_ptr->pass--; 1182 1183 if (png_ptr->pass >= 7) 1184 break; 1185 1186 png_ptr->iwidth = (png_ptr->width + 1187 png_pass_inc[png_ptr->pass] - 1 - 1188 png_pass_start[png_ptr->pass]) / 1189 png_pass_inc[png_ptr->pass]; 1190 1191 if (png_ptr->transformations & PNG_INTERLACE) 1192 break; 1193 1194 png_ptr->num_rows = (png_ptr->height + 1195 png_pass_yinc[png_ptr->pass] - 1 - 1196 png_pass_ystart[png_ptr->pass]) / 1197 png_pass_yinc[png_ptr->pass]; 1198 1199 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0); 1200 } 1201 #endif /* PNG_READ_INTERLACING_SUPPORTED */ 1202 } 1203 1204 #ifdef PNG_READ_tEXt_SUPPORTED 1205 void /* PRIVATE */ 1206 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 1207 length) 1208 { 1209 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND)) 1210 { 1211 png_error(png_ptr, "Out of place tEXt"); 1212 info_ptr = info_ptr; /* To quiet some compiler warnings */ 1213 } 1214 1215 #ifdef PNG_MAX_MALLOC_64K 1216 png_ptr->skip_length = 0; /* This may not be necessary */ 1217 1218 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */ 1219 { 1220 png_warning(png_ptr, "tEXt chunk too large to fit in memory"); 1221 png_ptr->skip_length = length - (png_uint_32)65535L; 1222 length = (png_uint_32)65535L; 1223 } 1224 #endif 1225 1226 png_ptr->current_text = (png_charp)png_malloc(png_ptr, 1227 (png_uint_32)(length + 1)); 1228 png_ptr->current_text[length] = '\0'; 1229 png_ptr->current_text_ptr = png_ptr->current_text; 1230 png_ptr->current_text_size = (png_size_t)length; 1231 png_ptr->current_text_left = (png_size_t)length; 1232 png_ptr->process_mode = PNG_READ_tEXt_MODE; 1233 } 1234 1235 void /* PRIVATE */ 1236 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr) 1237 { 1238 if (png_ptr->buffer_size && png_ptr->current_text_left) 1239 { 1240 png_size_t text_size; 1241 1242 if (png_ptr->buffer_size < png_ptr->current_text_left) 1243 text_size = png_ptr->buffer_size; 1244 1245 else 1246 text_size = png_ptr->current_text_left; 1247 1248 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size); 1249 png_ptr->current_text_left -= text_size; 1250 png_ptr->current_text_ptr += text_size; 1251 } 1252 if (!(png_ptr->current_text_left)) 1253 { 1254 png_textp text_ptr; 1255 png_charp text; 1256 png_charp key; 1257 int ret; 1258 1259 if (png_ptr->buffer_size < 4) 1260 { 1261 png_push_save_buffer(png_ptr); 1262 return; 1263 } 1264 1265 png_push_crc_finish(png_ptr); 1266 1267 #ifdef PNG_MAX_MALLOC_64K 1268 if (png_ptr->skip_length) 1269 return; 1270 #endif 1271 1272 key = png_ptr->current_text; 1273 1274 for (text = key; *text; text++) 1275 /* Empty loop */ ; 1276 1277 if (text < key + png_ptr->current_text_size) 1278 text++; 1279 1280 text_ptr = (png_textp)png_malloc(png_ptr, 1281 (png_uint_32)png_sizeof(png_text)); 1282 text_ptr->compression = PNG_TEXT_COMPRESSION_NONE; 1283 text_ptr->key = key; 1284 #ifdef PNG_iTXt_SUPPORTED 1285 text_ptr->lang = NULL; 1286 text_ptr->lang_key = NULL; 1287 #endif 1288 text_ptr->text = text; 1289 1290 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); 1291 1292 png_free(png_ptr, key); 1293 png_free(png_ptr, text_ptr); 1294 png_ptr->current_text = NULL; 1295 1296 if (ret) 1297 png_warning(png_ptr, "Insufficient memory to store text chunk."); 1298 } 1299 } 1300 #endif 1301 1302 #ifdef PNG_READ_zTXt_SUPPORTED 1303 void /* PRIVATE */ 1304 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 1305 length) 1306 { 1307 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND)) 1308 { 1309 png_error(png_ptr, "Out of place zTXt"); 1310 info_ptr = info_ptr; /* To quiet some compiler warnings */ 1311 } 1312 1313 #ifdef PNG_MAX_MALLOC_64K 1314 /* We can't handle zTXt chunks > 64K, since we don't have enough space 1315 * to be able to store the uncompressed data. Actually, the threshold 1316 * is probably around 32K, but it isn't as definite as 64K is. 1317 */ 1318 if (length > (png_uint_32)65535L) 1319 { 1320 png_warning(png_ptr, "zTXt chunk too large to fit in memory"); 1321 png_push_crc_skip(png_ptr, length); 1322 return; 1323 } 1324 #endif 1325 1326 png_ptr->current_text = (png_charp)png_malloc(png_ptr, 1327 (png_uint_32)(length + 1)); 1328 png_ptr->current_text[length] = '\0'; 1329 png_ptr->current_text_ptr = png_ptr->current_text; 1330 png_ptr->current_text_size = (png_size_t)length; 1331 png_ptr->current_text_left = (png_size_t)length; 1332 png_ptr->process_mode = PNG_READ_zTXt_MODE; 1333 } 1334 1335 void /* PRIVATE */ 1336 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr) 1337 { 1338 if (png_ptr->buffer_size && png_ptr->current_text_left) 1339 { 1340 png_size_t text_size; 1341 1342 if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left) 1343 text_size = png_ptr->buffer_size; 1344 1345 else 1346 text_size = png_ptr->current_text_left; 1347 1348 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size); 1349 png_ptr->current_text_left -= text_size; 1350 png_ptr->current_text_ptr += text_size; 1351 } 1352 if (!(png_ptr->current_text_left)) 1353 { 1354 png_textp text_ptr; 1355 png_charp text; 1356 png_charp key; 1357 int ret; 1358 png_size_t text_size, key_size; 1359 1360 if (png_ptr->buffer_size < 4) 1361 { 1362 png_push_save_buffer(png_ptr); 1363 return; 1364 } 1365 1366 png_push_crc_finish(png_ptr); 1367 1368 key = png_ptr->current_text; 1369 1370 for (text = key; *text; text++) 1371 /* Empty loop */ ; 1372 1373 /* zTXt can't have zero text */ 1374 if (text >= key + png_ptr->current_text_size) 1375 { 1376 png_ptr->current_text = NULL; 1377 png_free(png_ptr, key); 1378 return; 1379 } 1380 1381 text++; 1382 1383 if (*text != PNG_TEXT_COMPRESSION_zTXt) /* Check compression byte */ 1384 { 1385 png_ptr->current_text = NULL; 1386 png_free(png_ptr, key); 1387 return; 1388 } 1389 1390 text++; 1391 1392 png_ptr->zstream.next_in = (png_bytep )text; 1393 png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size - 1394 (text - key)); 1395 png_ptr->zstream.next_out = png_ptr->zbuf; 1396 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; 1397 1398 key_size = text - key; 1399 text_size = 0; 1400 text = NULL; 1401 ret = Z_STREAM_END; 1402 1403 while (png_ptr->zstream.avail_in) 1404 { 1405 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH); 1406 if (ret != Z_OK && ret != Z_STREAM_END) 1407 { 1408 inflateReset(&png_ptr->zstream); 1409 png_ptr->zstream.avail_in = 0; 1410 png_ptr->current_text = NULL; 1411 png_free(png_ptr, key); 1412 png_free(png_ptr, text); 1413 return; 1414 } 1415 if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END) 1416 { 1417 if (text == NULL) 1418 { 1419 text = (png_charp)png_malloc(png_ptr, 1420 (png_uint_32)(png_ptr->zbuf_size 1421 - png_ptr->zstream.avail_out + key_size + 1)); 1422 1423 png_memcpy(text + key_size, png_ptr->zbuf, 1424 png_ptr->zbuf_size - png_ptr->zstream.avail_out); 1425 1426 png_memcpy(text, key, key_size); 1427 1428 text_size = key_size + png_ptr->zbuf_size - 1429 png_ptr->zstream.avail_out; 1430 1431 *(text + text_size) = '\0'; 1432 } 1433 else 1434 { 1435 png_charp tmp; 1436 1437 tmp = text; 1438 text = (png_charp)png_malloc(png_ptr, text_size + 1439 (png_uint_32)(png_ptr->zbuf_size 1440 - png_ptr->zstream.avail_out + 1)); 1441 1442 png_memcpy(text, tmp, text_size); 1443 png_free(png_ptr, tmp); 1444 1445 png_memcpy(text + text_size, png_ptr->zbuf, 1446 png_ptr->zbuf_size - png_ptr->zstream.avail_out); 1447 1448 text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out; 1449 *(text + text_size) = '\0'; 1450 } 1451 if (ret != Z_STREAM_END) 1452 { 1453 png_ptr->zstream.next_out = png_ptr->zbuf; 1454 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; 1455 } 1456 } 1457 else 1458 { 1459 break; 1460 } 1461 1462 if (ret == Z_STREAM_END) 1463 break; 1464 } 1465 1466 inflateReset(&png_ptr->zstream); 1467 png_ptr->zstream.avail_in = 0; 1468 1469 if (ret != Z_STREAM_END) 1470 { 1471 png_ptr->current_text = NULL; 1472 png_free(png_ptr, key); 1473 png_free(png_ptr, text); 1474 return; 1475 } 1476 1477 png_ptr->current_text = NULL; 1478 png_free(png_ptr, key); 1479 key = text; 1480 text += key_size; 1481 1482 text_ptr = (png_textp)png_malloc(png_ptr, 1483 (png_uint_32)png_sizeof(png_text)); 1484 text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt; 1485 text_ptr->key = key; 1486 #ifdef PNG_iTXt_SUPPORTED 1487 text_ptr->lang = NULL; 1488 text_ptr->lang_key = NULL; 1489 #endif 1490 text_ptr->text = text; 1491 1492 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); 1493 1494 png_free(png_ptr, key); 1495 png_free(png_ptr, text_ptr); 1496 1497 if (ret) 1498 png_warning(png_ptr, "Insufficient memory to store text chunk."); 1499 } 1500 } 1501 #endif 1502 1503 #ifdef PNG_READ_iTXt_SUPPORTED 1504 void /* PRIVATE */ 1505 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 1506 length) 1507 { 1508 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND)) 1509 { 1510 png_error(png_ptr, "Out of place iTXt"); 1511 info_ptr = info_ptr; /* To quiet some compiler warnings */ 1512 } 1513 1514 #ifdef PNG_MAX_MALLOC_64K 1515 png_ptr->skip_length = 0; /* This may not be necessary */ 1516 1517 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */ 1518 { 1519 png_warning(png_ptr, "iTXt chunk too large to fit in memory"); 1520 png_ptr->skip_length = length - (png_uint_32)65535L; 1521 length = (png_uint_32)65535L; 1522 } 1523 #endif 1524 1525 png_ptr->current_text = (png_charp)png_malloc(png_ptr, 1526 (png_uint_32)(length + 1)); 1527 png_ptr->current_text[length] = '\0'; 1528 png_ptr->current_text_ptr = png_ptr->current_text; 1529 png_ptr->current_text_size = (png_size_t)length; 1530 png_ptr->current_text_left = (png_size_t)length; 1531 png_ptr->process_mode = PNG_READ_iTXt_MODE; 1532 } 1533 1534 void /* PRIVATE */ 1535 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr) 1536 { 1537 1538 if (png_ptr->buffer_size && png_ptr->current_text_left) 1539 { 1540 png_size_t text_size; 1541 1542 if (png_ptr->buffer_size < png_ptr->current_text_left) 1543 text_size = png_ptr->buffer_size; 1544 1545 else 1546 text_size = png_ptr->current_text_left; 1547 1548 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size); 1549 png_ptr->current_text_left -= text_size; 1550 png_ptr->current_text_ptr += text_size; 1551 } 1552 if (!(png_ptr->current_text_left)) 1553 { 1554 png_textp text_ptr; 1555 png_charp key; 1556 int comp_flag; 1557 png_charp lang; 1558 png_charp lang_key; 1559 png_charp text; 1560 int ret; 1561 1562 if (png_ptr->buffer_size < 4) 1563 { 1564 png_push_save_buffer(png_ptr); 1565 return; 1566 } 1567 1568 png_push_crc_finish(png_ptr); 1569 1570 #ifdef PNG_MAX_MALLOC_64K 1571 if (png_ptr->skip_length) 1572 return; 1573 #endif 1574 1575 key = png_ptr->current_text; 1576 1577 for (lang = key; *lang; lang++) 1578 /* Empty loop */ ; 1579 1580 if (lang < key + png_ptr->current_text_size - 3) 1581 lang++; 1582 1583 comp_flag = *lang++; 1584 lang++; /* Skip comp_type, always zero */ 1585 1586 for (lang_key = lang; *lang_key; lang_key++) 1587 /* Empty loop */ ; 1588 1589 lang_key++; /* Skip NUL separator */ 1590 1591 text=lang_key; 1592 1593 if (lang_key < key + png_ptr->current_text_size - 1) 1594 { 1595 for (; *text; text++) 1596 /* Empty loop */ ; 1597 } 1598 1599 if (text < key + png_ptr->current_text_size) 1600 text++; 1601 1602 text_ptr = (png_textp)png_malloc(png_ptr, 1603 (png_uint_32)png_sizeof(png_text)); 1604 1605 text_ptr->compression = comp_flag + 2; 1606 text_ptr->key = key; 1607 text_ptr->lang = lang; 1608 text_ptr->lang_key = lang_key; 1609 text_ptr->text = text; 1610 text_ptr->text_length = 0; 1611 text_ptr->itxt_length = png_strlen(text); 1612 1613 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1); 1614 1615 png_ptr->current_text = NULL; 1616 1617 png_free(png_ptr, text_ptr); 1618 if (ret) 1619 png_warning(png_ptr, "Insufficient memory to store iTXt chunk."); 1620 } 1621 } 1622 #endif 1623 1624 /* This function is called when we haven't found a handler for this 1625 * chunk. If there isn't a problem with the chunk itself (ie a bad chunk 1626 * name or a critical chunk), the chunk is (currently) silently ignored. 1627 */ 1628 void /* PRIVATE */ 1629 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 1630 length) 1631 { 1632 png_uint_32 skip = 0; 1633 1634 if (!(png_ptr->chunk_name[0] & 0x20)) 1635 { 1636 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 1637 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) != 1638 PNG_HANDLE_CHUNK_ALWAYS 1639 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED 1640 && png_ptr->read_user_chunk_fn == NULL 1641 #endif 1642 ) 1643 #endif 1644 png_chunk_error(png_ptr, "unknown critical chunk"); 1645 1646 info_ptr = info_ptr; /* To quiet some compiler warnings */ 1647 } 1648 1649 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED 1650 if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS) 1651 { 1652 #ifdef PNG_MAX_MALLOC_64K 1653 if (length > (png_uint_32)65535L) 1654 { 1655 png_warning(png_ptr, "unknown chunk too large to fit in memory"); 1656 skip = length - (png_uint_32)65535L; 1657 length = (png_uint_32)65535L; 1658 } 1659 #endif 1660 png_memcpy((png_charp)png_ptr->unknown_chunk.name, 1661 (png_charp)png_ptr->chunk_name, 1662 png_sizeof(png_ptr->unknown_chunk.name)); 1663 png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name) - 1] 1664 = '\0'; 1665 1666 png_ptr->unknown_chunk.size = (png_size_t)length; 1667 1668 if (length == 0) 1669 png_ptr->unknown_chunk.data = NULL; 1670 1671 else 1672 { 1673 png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, 1674 (png_uint_32)length); 1675 png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length); 1676 } 1677 1678 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED 1679 if (png_ptr->read_user_chunk_fn != NULL) 1680 { 1681 /* Callback to user unknown chunk handler */ 1682 int ret; 1683 ret = (*(png_ptr->read_user_chunk_fn)) 1684 (png_ptr, &png_ptr->unknown_chunk); 1685 1686 if (ret < 0) 1687 png_chunk_error(png_ptr, "error in user chunk"); 1688 1689 if (ret == 0) 1690 { 1691 if (!(png_ptr->chunk_name[0] & 0x20)) 1692 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) != 1693 PNG_HANDLE_CHUNK_ALWAYS) 1694 png_chunk_error(png_ptr, "unknown critical chunk"); 1695 png_set_unknown_chunks(png_ptr, info_ptr, 1696 &png_ptr->unknown_chunk, 1); 1697 } 1698 } 1699 1700 else 1701 #endif 1702 png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1); 1703 png_free(png_ptr, png_ptr->unknown_chunk.data); 1704 png_ptr->unknown_chunk.data = NULL; 1705 } 1706 1707 else 1708 #endif 1709 skip=length; 1710 png_push_crc_skip(png_ptr, skip); 1711 } 1712 1713 void /* PRIVATE */ 1714 png_push_have_info(png_structp png_ptr, png_infop info_ptr) 1715 { 1716 if (png_ptr->info_fn != NULL) 1717 (*(png_ptr->info_fn))(png_ptr, info_ptr); 1718 } 1719 1720 void /* PRIVATE */ 1721 png_push_have_end(png_structp png_ptr, png_infop info_ptr) 1722 { 1723 if (png_ptr->end_fn != NULL) 1724 (*(png_ptr->end_fn))(png_ptr, info_ptr); 1725 } 1726 1727 void /* PRIVATE */ 1728 png_push_have_row(png_structp png_ptr, png_bytep row) 1729 { 1730 if (png_ptr->row_fn != NULL) 1731 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number, 1732 (int)png_ptr->pass); 1733 } 1734 1735 void PNGAPI 1736 png_progressive_combine_row (png_structp png_ptr, 1737 png_bytep old_row, png_bytep new_row) 1738 { 1739 #ifdef PNG_USE_LOCAL_ARRAYS 1740 PNG_CONST int FARDATA png_pass_dsp_mask[7] = 1741 {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff}; 1742 #endif 1743 1744 if (png_ptr == NULL) 1745 return; 1746 1747 if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */ 1748 png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]); 1749 } 1750 1751 void PNGAPI 1752 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr, 1753 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, 1754 png_progressive_end_ptr end_fn) 1755 { 1756 if (png_ptr == NULL) 1757 return; 1758 1759 png_ptr->info_fn = info_fn; 1760 png_ptr->row_fn = row_fn; 1761 png_ptr->end_fn = end_fn; 1762 1763 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer); 1764 } 1765 1766 png_voidp PNGAPI 1767 png_get_progressive_ptr(png_structp png_ptr) 1768 { 1769 if (png_ptr == NULL) 1770 return (NULL); 1771 1772 return png_ptr->io_ptr; 1773 } 1774 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ 1775
