1 2 /* png.c - location for general purpose libpng functions 3 * 4 * Last changed in libpng 1.2.43 [February 25, 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_EXTERN 16 #define PNG_NO_PEDANTIC_WARNINGS 17 #include "png.h" 18 19 /* Generate a compiler error if there is an old png.h in the search path. */ 20 typedef version_1_2_44 Your_png_h_is_not_version_1_2_44; 21 22 /* Version information for C files. This had better match the version 23 * string defined in png.h. 24 */ 25 26 #ifdef PNG_USE_GLOBAL_ARRAYS 27 /* png_libpng_ver was changed to a function in version 1.0.5c */ 28 PNG_CONST char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING; 29 30 #ifdef PNG_READ_SUPPORTED 31 32 /* png_sig was changed to a function in version 1.0.5c */ 33 /* Place to hold the signature string for a PNG file. */ 34 PNG_CONST png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10}; 35 #endif /* PNG_READ_SUPPORTED */ 36 37 /* Invoke global declarations for constant strings for known chunk types */ 38 PNG_IHDR; 39 PNG_IDAT; 40 PNG_IEND; 41 PNG_PLTE; 42 PNG_bKGD; 43 PNG_cHRM; 44 PNG_gAMA; 45 PNG_hIST; 46 PNG_iCCP; 47 PNG_iTXt; 48 PNG_oFFs; 49 PNG_pCAL; 50 PNG_sCAL; 51 PNG_pHYs; 52 PNG_sBIT; 53 PNG_sPLT; 54 PNG_sRGB; 55 PNG_tEXt; 56 PNG_tIME; 57 PNG_tRNS; 58 PNG_zTXt; 59 60 #ifdef PNG_READ_SUPPORTED 61 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 62 63 /* Start of interlace block */ 64 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; 65 66 /* Offset to next interlace block */ 67 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; 68 69 /* Start of interlace block in the y direction */ 70 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; 71 72 /* Offset to next interlace block in the y direction */ 73 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; 74 75 /* Height of interlace block. This is not currently used - if you need 76 * it, uncomment it here and in png.h 77 PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; 78 */ 79 80 /* Mask to determine which pixels are valid in a pass */ 81 PNG_CONST int FARDATA png_pass_mask[] = 82 {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff}; 83 84 /* Mask to determine which pixels to overwrite while displaying */ 85 PNG_CONST int FARDATA png_pass_dsp_mask[] 86 = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff}; 87 88 #endif /* PNG_READ_SUPPORTED */ 89 #endif /* PNG_USE_GLOBAL_ARRAYS */ 90 91 /* Tells libpng that we have already handled the first "num_bytes" bytes 92 * of the PNG file signature. If the PNG data is embedded into another 93 * stream we can set num_bytes = 8 so that libpng will not attempt to read 94 * or write any of the magic bytes before it starts on the IHDR. 95 */ 96 97 #ifdef PNG_READ_SUPPORTED 98 void PNGAPI 99 png_set_sig_bytes(png_structp png_ptr, int num_bytes) 100 { 101 png_debug(1, "in png_set_sig_bytes"); 102 103 if (png_ptr == NULL) 104 return; 105 106 if (num_bytes > 8) 107 png_error(png_ptr, "Too many bytes for PNG signature."); 108 109 png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes); 110 } 111 112 /* Checks whether the supplied bytes match the PNG signature. We allow 113 * checking less than the full 8-byte signature so that those apps that 114 * already read the first few bytes of a file to determine the file type 115 * can simply check the remaining bytes for extra assurance. Returns 116 * an integer less than, equal to, or greater than zero if sig is found, 117 * respectively, to be less than, to match, or be greater than the correct 118 * PNG signature (this is the same behaviour as strcmp, memcmp, etc). 119 */ 120 int PNGAPI 121 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check) 122 { 123 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; 124 if (num_to_check > 8) 125 num_to_check = 8; 126 else if (num_to_check < 1) 127 return (-1); 128 129 if (start > 7) 130 return (-1); 131 132 if (start + num_to_check > 8) 133 num_to_check = 8 - start; 134 135 return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check))); 136 } 137 138 #if defined(PNG_1_0_X) || defined(PNG_1_2_X) 139 /* (Obsolete) function to check signature bytes. It does not allow one 140 * to check a partial signature. This function might be removed in the 141 * future - use png_sig_cmp(). Returns true (nonzero) if the file is PNG. 142 */ 143 int PNGAPI 144 png_check_sig(png_bytep sig, int num) 145 { 146 return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num)); 147 } 148 #endif 149 #endif /* PNG_READ_SUPPORTED */ 150 151 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 152 /* Function to allocate memory for zlib and clear it to 0. */ 153 #ifdef PNG_1_0_X 154 voidpf PNGAPI 155 #else 156 voidpf /* PRIVATE */ 157 #endif 158 png_zalloc(voidpf png_ptr, uInt items, uInt size) 159 { 160 png_voidp ptr; 161 png_structp p=(png_structp)png_ptr; 162 png_uint_32 save_flags=p->flags; 163 png_uint_32 num_bytes; 164 165 if (png_ptr == NULL) 166 return (NULL); 167 if (items > PNG_UINT_32_MAX/size) 168 { 169 png_warning (p, "Potential overflow in png_zalloc()"); 170 return (NULL); 171 } 172 num_bytes = (png_uint_32)items * size; 173 174 p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK; 175 ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes); 176 p->flags=save_flags; 177 178 #if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO) 179 if (ptr == NULL) 180 return ((voidpf)ptr); 181 182 if (num_bytes > (png_uint_32)0x8000L) 183 { 184 png_memset(ptr, 0, (png_size_t)0x8000L); 185 png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0, 186 (png_size_t)(num_bytes - (png_uint_32)0x8000L)); 187 } 188 else 189 { 190 png_memset(ptr, 0, (png_size_t)num_bytes); 191 } 192 #endif 193 return ((voidpf)ptr); 194 } 195 196 /* Function to free memory for zlib */ 197 #ifdef PNG_1_0_X 198 void PNGAPI 199 #else 200 void /* PRIVATE */ 201 #endif 202 png_zfree(voidpf png_ptr, voidpf ptr) 203 { 204 png_free((png_structp)png_ptr, (png_voidp)ptr); 205 } 206 207 /* Reset the CRC variable to 32 bits of 1's. Care must be taken 208 * in case CRC is > 32 bits to leave the top bits 0. 209 */ 210 void /* PRIVATE */ 211 png_reset_crc(png_structp png_ptr) 212 { 213 png_ptr->crc = crc32(0, Z_NULL, 0); 214 } 215 216 /* Calculate the CRC over a section of data. We can only pass as 217 * much data to this routine as the largest single buffer size. We 218 * also check that this data will actually be used before going to the 219 * trouble of calculating it. 220 */ 221 void /* PRIVATE */ 222 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length) 223 { 224 int need_crc = 1; 225 226 if (png_ptr->chunk_name[0] & 0x20) /* ancillary */ 227 { 228 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == 229 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) 230 need_crc = 0; 231 } 232 else /* critical */ 233 { 234 if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) 235 need_crc = 0; 236 } 237 238 if (need_crc) 239 png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length); 240 } 241 242 /* Allocate the memory for an info_struct for the application. We don't 243 * really need the png_ptr, but it could potentially be useful in the 244 * future. This should be used in favour of malloc(png_sizeof(png_info)) 245 * and png_info_init() so that applications that want to use a shared 246 * libpng don't have to be recompiled if png_info changes size. 247 */ 248 png_infop PNGAPI 249 png_create_info_struct(png_structp png_ptr) 250 { 251 png_infop info_ptr; 252 253 png_debug(1, "in png_create_info_struct"); 254 255 if (png_ptr == NULL) 256 return (NULL); 257 258 #ifdef PNG_USER_MEM_SUPPORTED 259 info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO, 260 png_ptr->malloc_fn, png_ptr->mem_ptr); 261 #else 262 info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); 263 #endif 264 if (info_ptr != NULL) 265 png_info_init_3(&info_ptr, png_sizeof(png_info)); 266 267 return (info_ptr); 268 } 269 270 /* This function frees the memory associated with a single info struct. 271 * Normally, one would use either png_destroy_read_struct() or 272 * png_destroy_write_struct() to free an info struct, but this may be 273 * useful for some applications. 274 */ 275 void PNGAPI 276 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr) 277 { 278 png_infop info_ptr = NULL; 279 280 png_debug(1, "in png_destroy_info_struct"); 281 282 if (png_ptr == NULL) 283 return; 284 285 if (info_ptr_ptr != NULL) 286 info_ptr = *info_ptr_ptr; 287 288 if (info_ptr != NULL) 289 { 290 png_info_destroy(png_ptr, info_ptr); 291 292 #ifdef PNG_USER_MEM_SUPPORTED 293 png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn, 294 png_ptr->mem_ptr); 295 #else 296 png_destroy_struct((png_voidp)info_ptr); 297 #endif 298 *info_ptr_ptr = NULL; 299 } 300 } 301 302 /* Initialize the info structure. This is now an internal function (0.89) 303 * and applications using it are urged to use png_create_info_struct() 304 * instead. 305 */ 306 #if defined(PNG_1_0_X) || defined(PNG_1_2_X) 307 #undef png_info_init 308 void PNGAPI 309 png_info_init(png_infop info_ptr) 310 { 311 /* We only come here via pre-1.0.12-compiled applications */ 312 png_info_init_3(&info_ptr, 0); 313 } 314 #endif 315 316 void PNGAPI 317 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size) 318 { 319 png_infop info_ptr = *ptr_ptr; 320 321 png_debug(1, "in png_info_init_3"); 322 323 if (info_ptr == NULL) 324 return; 325 326 if (png_sizeof(png_info) > png_info_struct_size) 327 { 328 png_destroy_struct(info_ptr); 329 info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); 330 *ptr_ptr = info_ptr; 331 } 332 333 /* Set everything to 0 */ 334 png_memset(info_ptr, 0, png_sizeof(png_info)); 335 } 336 337 #ifdef PNG_FREE_ME_SUPPORTED 338 void PNGAPI 339 png_data_freer(png_structp png_ptr, png_infop info_ptr, 340 int freer, png_uint_32 mask) 341 { 342 png_debug(1, "in png_data_freer"); 343 344 if (png_ptr == NULL || info_ptr == NULL) 345 return; 346 347 if (freer == PNG_DESTROY_WILL_FREE_DATA) 348 info_ptr->free_me |= mask; 349 else if (freer == PNG_USER_WILL_FREE_DATA) 350 info_ptr->free_me &= ~mask; 351 else 352 png_warning(png_ptr, 353 "Unknown freer parameter in png_data_freer."); 354 } 355 #endif 356 357 void PNGAPI 358 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, 359 int num) 360 { 361 png_debug(1, "in png_free_data"); 362 363 if (png_ptr == NULL || info_ptr == NULL) 364 return; 365 366 #ifdef PNG_TEXT_SUPPORTED 367 /* Free text item num or (if num == -1) all text items */ 368 #ifdef PNG_FREE_ME_SUPPORTED 369 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me) 370 #else 371 if (mask & PNG_FREE_TEXT) 372 #endif 373 { 374 if (num != -1) 375 { 376 if (info_ptr->text && info_ptr->text[num].key) 377 { 378 png_free(png_ptr, info_ptr->text[num].key); 379 info_ptr->text[num].key = NULL; 380 } 381 } 382 else 383 { 384 int i; 385 for (i = 0; i < info_ptr->num_text; i++) 386 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i); 387 png_free(png_ptr, info_ptr->text); 388 info_ptr->text = NULL; 389 info_ptr->num_text=0; 390 } 391 } 392 #endif 393 394 #ifdef PNG_tRNS_SUPPORTED 395 /* Free any tRNS entry */ 396 #ifdef PNG_FREE_ME_SUPPORTED 397 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me) 398 #else 399 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS)) 400 #endif 401 { 402 png_free(png_ptr, info_ptr->trans); 403 info_ptr->trans = NULL; 404 info_ptr->valid &= ~PNG_INFO_tRNS; 405 #ifndef PNG_FREE_ME_SUPPORTED 406 png_ptr->flags &= ~PNG_FLAG_FREE_TRNS; 407 #endif 408 } 409 #endif 410 411 #ifdef PNG_sCAL_SUPPORTED 412 /* Free any sCAL entry */ 413 #ifdef PNG_FREE_ME_SUPPORTED 414 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me) 415 #else 416 if (mask & PNG_FREE_SCAL) 417 #endif 418 { 419 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED) 420 png_free(png_ptr, info_ptr->scal_s_width); 421 png_free(png_ptr, info_ptr->scal_s_height); 422 info_ptr->scal_s_width = NULL; 423 info_ptr->scal_s_height = NULL; 424 #endif 425 info_ptr->valid &= ~PNG_INFO_sCAL; 426 } 427 #endif 428 429 #ifdef PNG_pCAL_SUPPORTED 430 /* Free any pCAL entry */ 431 #ifdef PNG_FREE_ME_SUPPORTED 432 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me) 433 #else 434 if (mask & PNG_FREE_PCAL) 435 #endif 436 { 437 png_free(png_ptr, info_ptr->pcal_purpose); 438 png_free(png_ptr, info_ptr->pcal_units); 439 info_ptr->pcal_purpose = NULL; 440 info_ptr->pcal_units = NULL; 441 if (info_ptr->pcal_params != NULL) 442 { 443 int i; 444 for (i = 0; i < (int)info_ptr->pcal_nparams; i++) 445 { 446 png_free(png_ptr, info_ptr->pcal_params[i]); 447 info_ptr->pcal_params[i] = NULL; 448 } 449 png_free(png_ptr, info_ptr->pcal_params); 450 info_ptr->pcal_params = NULL; 451 } 452 info_ptr->valid &= ~PNG_INFO_pCAL; 453 } 454 #endif 455 456 #ifdef PNG_iCCP_SUPPORTED 457 /* Free any iCCP entry */ 458 #ifdef PNG_FREE_ME_SUPPORTED 459 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me) 460 #else 461 if (mask & PNG_FREE_ICCP) 462 #endif 463 { 464 png_free(png_ptr, info_ptr->iccp_name); 465 png_free(png_ptr, info_ptr->iccp_profile); 466 info_ptr->iccp_name = NULL; 467 info_ptr->iccp_profile = NULL; 468 info_ptr->valid &= ~PNG_INFO_iCCP; 469 } 470 #endif 471 472 #ifdef PNG_sPLT_SUPPORTED 473 /* Free a given sPLT entry, or (if num == -1) all sPLT entries */ 474 #ifdef PNG_FREE_ME_SUPPORTED 475 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me) 476 #else 477 if (mask & PNG_FREE_SPLT) 478 #endif 479 { 480 if (num != -1) 481 { 482 if (info_ptr->splt_palettes) 483 { 484 png_free(png_ptr, info_ptr->splt_palettes[num].name); 485 png_free(png_ptr, info_ptr->splt_palettes[num].entries); 486 info_ptr->splt_palettes[num].name = NULL; 487 info_ptr->splt_palettes[num].entries = NULL; 488 } 489 } 490 else 491 { 492 if (info_ptr->splt_palettes_num) 493 { 494 int i; 495 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++) 496 png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i); 497 498 png_free(png_ptr, info_ptr->splt_palettes); 499 info_ptr->splt_palettes = NULL; 500 info_ptr->splt_palettes_num = 0; 501 } 502 info_ptr->valid &= ~PNG_INFO_sPLT; 503 } 504 } 505 #endif 506 507 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED 508 if (png_ptr->unknown_chunk.data) 509 { 510 png_free(png_ptr, png_ptr->unknown_chunk.data); 511 png_ptr->unknown_chunk.data = NULL; 512 } 513 514 #ifdef PNG_FREE_ME_SUPPORTED 515 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me) 516 #else 517 if (mask & PNG_FREE_UNKN) 518 #endif 519 { 520 if (num != -1) 521 { 522 if (info_ptr->unknown_chunks) 523 { 524 png_free(png_ptr, info_ptr->unknown_chunks[num].data); 525 info_ptr->unknown_chunks[num].data = NULL; 526 } 527 } 528 else 529 { 530 int i; 531 532 if (info_ptr->unknown_chunks_num) 533 { 534 for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++) 535 png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i); 536 537 png_free(png_ptr, info_ptr->unknown_chunks); 538 info_ptr->unknown_chunks = NULL; 539 info_ptr->unknown_chunks_num = 0; 540 } 541 } 542 } 543 #endif 544 545 #ifdef PNG_hIST_SUPPORTED 546 /* Free any hIST entry */ 547 #ifdef PNG_FREE_ME_SUPPORTED 548 if ((mask & PNG_FREE_HIST) & info_ptr->free_me) 549 #else 550 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST)) 551 #endif 552 { 553 png_free(png_ptr, info_ptr->hist); 554 info_ptr->hist = NULL; 555 info_ptr->valid &= ~PNG_INFO_hIST; 556 #ifndef PNG_FREE_ME_SUPPORTED 557 png_ptr->flags &= ~PNG_FLAG_FREE_HIST; 558 #endif 559 } 560 #endif 561 562 /* Free any PLTE entry that was internally allocated */ 563 #ifdef PNG_FREE_ME_SUPPORTED 564 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me) 565 #else 566 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE)) 567 #endif 568 { 569 png_zfree(png_ptr, info_ptr->palette); 570 info_ptr->palette = NULL; 571 info_ptr->valid &= ~PNG_INFO_PLTE; 572 #ifndef PNG_FREE_ME_SUPPORTED 573 png_ptr->flags &= ~PNG_FLAG_FREE_PLTE; 574 #endif 575 info_ptr->num_palette = 0; 576 } 577 578 #ifdef PNG_INFO_IMAGE_SUPPORTED 579 /* Free any image bits attached to the info structure */ 580 #ifdef PNG_FREE_ME_SUPPORTED 581 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me) 582 #else 583 if (mask & PNG_FREE_ROWS) 584 #endif 585 { 586 if (info_ptr->row_pointers) 587 { 588 int row; 589 for (row = 0; row < (int)info_ptr->height; row++) 590 { 591 png_free(png_ptr, info_ptr->row_pointers[row]); 592 info_ptr->row_pointers[row] = NULL; 593 } 594 png_free(png_ptr, info_ptr->row_pointers); 595 info_ptr->row_pointers = NULL; 596 } 597 info_ptr->valid &= ~PNG_INFO_IDAT; 598 } 599 #endif 600 601 #ifdef PNG_FREE_ME_SUPPORTED 602 if (num == -1) 603 info_ptr->free_me &= ~mask; 604 else 605 info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL); 606 #endif 607 } 608 609 /* This is an internal routine to free any memory that the info struct is 610 * pointing to before re-using it or freeing the struct itself. Recall 611 * that png_free() checks for NULL pointers for us. 612 */ 613 void /* PRIVATE */ 614 png_info_destroy(png_structp png_ptr, png_infop info_ptr) 615 { 616 png_debug(1, "in png_info_destroy"); 617 618 png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); 619 620 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 621 if (png_ptr->num_chunk_list) 622 { 623 png_free(png_ptr, png_ptr->chunk_list); 624 png_ptr->chunk_list = NULL; 625 png_ptr->num_chunk_list = 0; 626 } 627 #endif 628 629 png_info_init_3(&info_ptr, png_sizeof(png_info)); 630 } 631 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 632 633 /* This function returns a pointer to the io_ptr associated with the user 634 * functions. The application should free any memory associated with this 635 * pointer before png_write_destroy() or png_read_destroy() are called. 636 */ 637 png_voidp PNGAPI 638 png_get_io_ptr(png_structp png_ptr) 639 { 640 if (png_ptr == NULL) 641 return (NULL); 642 return (png_ptr->io_ptr); 643 } 644 645 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 646 #ifdef PNG_STDIO_SUPPORTED 647 /* Initialize the default input/output functions for the PNG file. If you 648 * use your own read or write routines, you can call either png_set_read_fn() 649 * or png_set_write_fn() instead of png_init_io(). If you have defined 650 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't 651 * necessarily available. 652 */ 653 void PNGAPI 654 png_init_io(png_structp png_ptr, png_FILE_p fp) 655 { 656 png_debug(1, "in png_init_io"); 657 658 if (png_ptr == NULL) 659 return; 660 661 png_ptr->io_ptr = (png_voidp)fp; 662 } 663 #endif 664 665 #ifdef PNG_TIME_RFC1123_SUPPORTED 666 /* Convert the supplied time into an RFC 1123 string suitable for use in 667 * a "Creation Time" or other text-based time string. 668 */ 669 png_charp PNGAPI 670 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime) 671 { 672 static PNG_CONST char short_months[12][4] = 673 {"Jan", "Feb", "Mar", "Apr", "May", "Jun", 674 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; 675 676 if (png_ptr == NULL) 677 return (NULL); 678 if (png_ptr->time_buffer == NULL) 679 { 680 png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29* 681 png_sizeof(char))); 682 } 683 684 #ifdef _WIN32_WCE 685 { 686 wchar_t time_buf[29]; 687 wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"), 688 ptime->day % 32, short_months[(ptime->month - 1) % 12], 689 ptime->year, ptime->hour % 24, ptime->minute % 60, 690 ptime->second % 61); 691 WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 692 29, NULL, NULL); 693 } 694 #else 695 #ifdef USE_FAR_KEYWORD 696 { 697 char near_time_buf[29]; 698 png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000", 699 ptime->day % 32, short_months[(ptime->month - 1) % 12], 700 ptime->year, ptime->hour % 24, ptime->minute % 60, 701 ptime->second % 61); 702 png_memcpy(png_ptr->time_buffer, near_time_buf, 703 29*png_sizeof(char)); 704 } 705 #else 706 png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000", 707 ptime->day % 32, short_months[(ptime->month - 1) % 12], 708 ptime->year, ptime->hour % 24, ptime->minute % 60, 709 ptime->second % 61); 710 #endif 711 #endif /* _WIN32_WCE */ 712 return ((png_charp)png_ptr->time_buffer); 713 } 714 #endif /* PNG_TIME_RFC1123_SUPPORTED */ 715 716 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 717 718 png_charp PNGAPI 719 png_get_copyright(png_structp png_ptr) 720 { 721 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 722 #ifdef PNG_STRING_COPYRIGHT 723 return PNG_STRING_COPYRIGHT 724 #else 725 #ifdef __STDC__ 726 return ((png_charp) PNG_STRING_NEWLINE \ 727 "libpng version 1.2.44 - June 26, 2010" PNG_STRING_NEWLINE \ 728 "Copyright (c) 1998-2010 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ 729 "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ 730 "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ 731 PNG_STRING_NEWLINE); 732 #else 733 return ((png_charp) "libpng version 1.2.44 - June 26, 2010\ 734 Copyright (c) 1998-2010 Glenn Randers-Pehrson\ 735 Copyright (c) 1996-1997 Andreas Dilger\ 736 Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."); 737 #endif 738 #endif 739 } 740 741 /* The following return the library version as a short string in the 742 * format 1.0.0 through 99.99.99zz. To get the version of *.h files 743 * used with your application, print out PNG_LIBPNG_VER_STRING, which 744 * is defined in png.h. 745 * Note: now there is no difference between png_get_libpng_ver() and 746 * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard, 747 * it is guaranteed that png.c uses the correct version of png.h. 748 */ 749 png_charp PNGAPI 750 png_get_libpng_ver(png_structp png_ptr) 751 { 752 /* Version of *.c files used when building libpng */ 753 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 754 return ((png_charp) PNG_LIBPNG_VER_STRING); 755 } 756 757 png_charp PNGAPI 758 png_get_header_ver(png_structp png_ptr) 759 { 760 /* Version of *.h files used when building libpng */ 761 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 762 return ((png_charp) PNG_LIBPNG_VER_STRING); 763 } 764 765 png_charp PNGAPI 766 png_get_header_version(png_structp png_ptr) 767 { 768 /* Returns longer string containing both version and date */ 769 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 770 #ifdef __STDC__ 771 return ((png_charp) PNG_HEADER_VERSION_STRING 772 #ifndef PNG_READ_SUPPORTED 773 " (NO READ SUPPORT)" 774 #endif 775 PNG_STRING_NEWLINE); 776 #else 777 return ((png_charp) PNG_HEADER_VERSION_STRING); 778 #endif 779 } 780 781 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 782 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 783 int PNGAPI 784 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name) 785 { 786 /* Check chunk_name and return "keep" value if it's on the list, else 0 */ 787 int i; 788 png_bytep p; 789 if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0) 790 return 0; 791 p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5; 792 for (i = png_ptr->num_chunk_list; i; i--, p -= 5) 793 if (!png_memcmp(chunk_name, p, 4)) 794 return ((int)*(p + 4)); 795 return 0; 796 } 797 #endif 798 799 /* This function, added to libpng-1.0.6g, is untested. */ 800 int PNGAPI 801 png_reset_zstream(png_structp png_ptr) 802 { 803 if (png_ptr == NULL) 804 return Z_STREAM_ERROR; 805 return (inflateReset(&png_ptr->zstream)); 806 } 807 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 808 809 /* This function was added to libpng-1.0.7 */ 810 png_uint_32 PNGAPI 811 png_access_version_number(void) 812 { 813 /* Version of *.c files used when building libpng */ 814 return((png_uint_32) PNG_LIBPNG_VER); 815 } 816 817 818 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED) 819 #ifndef PNG_1_0_X 820 /* This function was added to libpng 1.2.0 */ 821 int PNGAPI 822 png_mmx_support(void) 823 { 824 /* Obsolete, to be removed from libpng-1.4.0 */ 825 return -1; 826 } 827 #endif /* PNG_1_0_X */ 828 #endif /* PNG_READ_SUPPORTED && PNG_ASSEMBLER_CODE_SUPPORTED */ 829 830 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 831 #ifdef PNG_SIZE_T 832 /* Added at libpng version 1.2.6 */ 833 PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size)); 834 png_size_t PNGAPI 835 png_convert_size(size_t size) 836 { 837 if (size > (png_size_t)-1) 838 PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */ 839 return ((png_size_t)size); 840 } 841 #endif /* PNG_SIZE_T */ 842 843 /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ 844 #ifdef PNG_cHRM_SUPPORTED 845 #ifdef PNG_CHECK_cHRM_SUPPORTED 846 847 /* 848 * Multiply two 32-bit numbers, V1 and V2, using 32-bit 849 * arithmetic, to produce a 64 bit result in the HI/LO words. 850 * 851 * A B 852 * x C D 853 * ------ 854 * AD || BD 855 * AC || CB || 0 856 * 857 * where A and B are the high and low 16-bit words of V1, 858 * C and D are the 16-bit words of V2, AD is the product of 859 * A and D, and X || Y is (X << 16) + Y. 860 */ 861 862 void /* PRIVATE */ 863 png_64bit_product (long v1, long v2, unsigned long *hi_product, 864 unsigned long *lo_product) 865 { 866 int a, b, c, d; 867 long lo, hi, x, y; 868 869 a = (v1 >> 16) & 0xffff; 870 b = v1 & 0xffff; 871 c = (v2 >> 16) & 0xffff; 872 d = v2 & 0xffff; 873 874 lo = b * d; /* BD */ 875 x = a * d + c * b; /* AD + CB */ 876 y = ((lo >> 16) & 0xffff) + x; 877 878 lo = (lo & 0xffff) | ((y & 0xffff) << 16); 879 hi = (y >> 16) & 0xffff; 880 881 hi += a * c; /* AC */ 882 883 *hi_product = (unsigned long)hi; 884 *lo_product = (unsigned long)lo; 885 } 886 887 int /* PRIVATE */ 888 png_check_cHRM_fixed(png_structp png_ptr, 889 png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x, 890 png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y, 891 png_fixed_point blue_x, png_fixed_point blue_y) 892 { 893 int ret = 1; 894 unsigned long xy_hi,xy_lo,yx_hi,yx_lo; 895 896 png_debug(1, "in function png_check_cHRM_fixed"); 897 898 if (png_ptr == NULL) 899 return 0; 900 901 if (white_x < 0 || white_y <= 0 || 902 red_x < 0 || red_y < 0 || 903 green_x < 0 || green_y < 0 || 904 blue_x < 0 || blue_y < 0) 905 { 906 png_warning(png_ptr, 907 "Ignoring attempt to set negative chromaticity value"); 908 ret = 0; 909 } 910 if (white_x > (png_fixed_point) PNG_UINT_31_MAX || 911 white_y > (png_fixed_point) PNG_UINT_31_MAX || 912 red_x > (png_fixed_point) PNG_UINT_31_MAX || 913 red_y > (png_fixed_point) PNG_UINT_31_MAX || 914 green_x > (png_fixed_point) PNG_UINT_31_MAX || 915 green_y > (png_fixed_point) PNG_UINT_31_MAX || 916 blue_x > (png_fixed_point) PNG_UINT_31_MAX || 917 blue_y > (png_fixed_point) PNG_UINT_31_MAX ) 918 { 919 png_warning(png_ptr, 920 "Ignoring attempt to set chromaticity value exceeding 21474.83"); 921 ret = 0; 922 } 923 if (white_x > 100000L - white_y) 924 { 925 png_warning(png_ptr, "Invalid cHRM white point"); 926 ret = 0; 927 } 928 if (red_x > 100000L - red_y) 929 { 930 png_warning(png_ptr, "Invalid cHRM red point"); 931 ret = 0; 932 } 933 if (green_x > 100000L - green_y) 934 { 935 png_warning(png_ptr, "Invalid cHRM green point"); 936 ret = 0; 937 } 938 if (blue_x > 100000L - blue_y) 939 { 940 png_warning(png_ptr, "Invalid cHRM blue point"); 941 ret = 0; 942 } 943 944 png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo); 945 png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo); 946 947 if (xy_hi == yx_hi && xy_lo == yx_lo) 948 { 949 png_warning(png_ptr, 950 "Ignoring attempt to set cHRM RGB triangle with zero area"); 951 ret = 0; 952 } 953 954 return ret; 955 } 956 #endif /* PNG_CHECK_cHRM_SUPPORTED */ 957 #endif /* PNG_cHRM_SUPPORTED */ 958 959 void /* PRIVATE */ 960 png_check_IHDR(png_structp png_ptr, 961 png_uint_32 width, png_uint_32 height, int bit_depth, 962 int color_type, int interlace_type, int compression_type, 963 int filter_type) 964 { 965 int error = 0; 966 967 /* Check for width and height valid values */ 968 if (width == 0) 969 { 970 png_warning(png_ptr, "Image width is zero in IHDR"); 971 error = 1; 972 } 973 974 if (height == 0) 975 { 976 png_warning(png_ptr, "Image height is zero in IHDR"); 977 error = 1; 978 } 979 980 #ifdef PNG_SET_USER_LIMITS_SUPPORTED 981 if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX) 982 #else 983 if (width > PNG_USER_WIDTH_MAX) 984 #endif 985 { 986 png_warning(png_ptr, "Image width exceeds user limit in IHDR"); 987 error = 1; 988 } 989 990 #ifdef PNG_SET_USER_LIMITS_SUPPORTED 991 if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX) 992 #else 993 if (height > PNG_USER_HEIGHT_MAX) 994 #endif 995 { 996 png_warning(png_ptr, "Image height exceeds user limit in IHDR"); 997 error = 1; 998 } 999 1000 if (width > PNG_UINT_31_MAX) 1001 { 1002 png_warning(png_ptr, "Invalid image width in IHDR"); 1003 error = 1; 1004 } 1005 1006 if ( height > PNG_UINT_31_MAX) 1007 { 1008 png_warning(png_ptr, "Invalid image height in IHDR"); 1009 error = 1; 1010 } 1011 1012 if ( width > (PNG_UINT_32_MAX 1013 >> 3) /* 8-byte RGBA pixels */ 1014 - 64 /* bigrowbuf hack */ 1015 - 1 /* filter byte */ 1016 - 7*8 /* rounding of width to multiple of 8 pixels */ 1017 - 8) /* extra max_pixel_depth pad */ 1018 png_warning(png_ptr, "Width is too large for libpng to process pixels"); 1019 1020 /* Check other values */ 1021 if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && 1022 bit_depth != 8 && bit_depth != 16) 1023 { 1024 png_warning(png_ptr, "Invalid bit depth in IHDR"); 1025 error = 1; 1026 } 1027 1028 if (color_type < 0 || color_type == 1 || 1029 color_type == 5 || color_type > 6) 1030 { 1031 png_warning(png_ptr, "Invalid color type in IHDR"); 1032 error = 1; 1033 } 1034 1035 if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) || 1036 ((color_type == PNG_COLOR_TYPE_RGB || 1037 color_type == PNG_COLOR_TYPE_GRAY_ALPHA || 1038 color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8)) 1039 { 1040 png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR"); 1041 error = 1; 1042 } 1043 1044 if (interlace_type >= PNG_INTERLACE_LAST) 1045 { 1046 png_warning(png_ptr, "Unknown interlace method in IHDR"); 1047 error = 1; 1048 } 1049 1050 if (compression_type != PNG_COMPRESSION_TYPE_BASE) 1051 { 1052 png_warning(png_ptr, "Unknown compression method in IHDR"); 1053 error = 1; 1054 } 1055 1056 #ifdef PNG_MNG_FEATURES_SUPPORTED 1057 /* Accept filter_method 64 (intrapixel differencing) only if 1058 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and 1059 * 2. Libpng did not read a PNG signature (this filter_method is only 1060 * used in PNG datastreams that are embedded in MNG datastreams) and 1061 * 3. The application called png_permit_mng_features with a mask that 1062 * included PNG_FLAG_MNG_FILTER_64 and 1063 * 4. The filter_method is 64 and 1064 * 5. The color_type is RGB or RGBA 1065 */ 1066 if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) && 1067 png_ptr->mng_features_permitted) 1068 png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); 1069 1070 if (filter_type != PNG_FILTER_TYPE_BASE) 1071 { 1072 if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && 1073 (filter_type == PNG_INTRAPIXEL_DIFFERENCING) && 1074 ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && 1075 (color_type == PNG_COLOR_TYPE_RGB || 1076 color_type == PNG_COLOR_TYPE_RGB_ALPHA))) 1077 { 1078 png_warning(png_ptr, "Unknown filter method in IHDR"); 1079 error = 1; 1080 } 1081 1082 if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) 1083 { 1084 png_warning(png_ptr, "Invalid filter method in IHDR"); 1085 error = 1; 1086 } 1087 } 1088 1089 #else 1090 if (filter_type != PNG_FILTER_TYPE_BASE) 1091 { 1092 png_warning(png_ptr, "Unknown filter method in IHDR"); 1093 error = 1; 1094 } 1095 #endif 1096 1097 if (error == 1) 1098 png_error(png_ptr, "Invalid IHDR data"); 1099 } 1100 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 1101
