1 2 /* png.c - location for general purpose libpng functions 3 * 4 * Last changed in libpng 1.2.46 [February 25, 2011] 5 * Copyright (c) 1998-2011 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 #include <stdint.h> 19 20 /* Generate a compiler error if there is an old png.h in the search path. */ 21 typedef version_1_2_46 Your_png_h_is_not_version_1_2_46; 22 23 /* Version information for C files. This had better match the version 24 * string defined in png.h. 25 */ 26 27 #ifdef PNG_USE_GLOBAL_ARRAYS 28 /* png_libpng_ver was changed to a function in version 1.0.5c */ 29 PNG_CONST char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING; 30 31 #ifdef PNG_READ_SUPPORTED 32 33 /* png_sig was changed to a function in version 1.0.5c */ 34 /* Place to hold the signature string for a PNG file. */ 35 PNG_CONST png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10}; 36 #endif /* PNG_READ_SUPPORTED */ 37 38 /* Invoke global declarations for constant strings for known chunk types */ 39 PNG_IHDR; 40 PNG_IDAT; 41 PNG_IEND; 42 PNG_PLTE; 43 PNG_bKGD; 44 PNG_cHRM; 45 PNG_gAMA; 46 PNG_hIST; 47 PNG_iCCP; 48 PNG_iTXt; 49 PNG_oFFs; 50 PNG_pCAL; 51 PNG_sCAL; 52 PNG_pHYs; 53 PNG_sBIT; 54 PNG_sPLT; 55 PNG_sRGB; 56 PNG_tEXt; 57 PNG_tIME; 58 PNG_tRNS; 59 PNG_zTXt; 60 61 #ifdef PNG_READ_SUPPORTED 62 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ 63 64 /* Start of interlace block */ 65 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; 66 67 /* Offset to next interlace block */ 68 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; 69 70 /* Start of interlace block in the y direction */ 71 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; 72 73 /* Offset to next interlace block in the y direction */ 74 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; 75 76 /* Height of interlace block. This is not currently used - if you need 77 * it, uncomment it here and in png.h 78 PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; 79 */ 80 81 /* Mask to determine which pixels are valid in a pass */ 82 PNG_CONST int FARDATA png_pass_mask[] = 83 {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff}; 84 85 /* Mask to determine which pixels to overwrite while displaying */ 86 PNG_CONST int FARDATA png_pass_dsp_mask[] 87 = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff}; 88 89 #endif /* PNG_READ_SUPPORTED */ 90 #endif /* PNG_USE_GLOBAL_ARRAYS */ 91 92 /* Tells libpng that we have already handled the first "num_bytes" bytes 93 * of the PNG file signature. If the PNG data is embedded into another 94 * stream we can set num_bytes = 8 so that libpng will not attempt to read 95 * or write any of the magic bytes before it starts on the IHDR. 96 */ 97 98 #ifdef PNG_READ_SUPPORTED 99 void PNGAPI 100 png_set_sig_bytes(png_structp png_ptr, int num_bytes) 101 { 102 png_debug(1, "in png_set_sig_bytes"); 103 104 if (png_ptr == NULL) 105 return; 106 107 if (num_bytes > 8) 108 png_error(png_ptr, "Too many bytes for PNG signature."); 109 110 png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes); 111 } 112 113 /* Checks whether the supplied bytes match the PNG signature. We allow 114 * checking less than the full 8-byte signature so that those apps that 115 * already read the first few bytes of a file to determine the file type 116 * can simply check the remaining bytes for extra assurance. Returns 117 * an integer less than, equal to, or greater than zero if sig is found, 118 * respectively, to be less than, to match, or be greater than the correct 119 * PNG signature (this is the same behaviour as strcmp, memcmp, etc). 120 */ 121 int PNGAPI 122 png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check) 123 { 124 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; 125 if (num_to_check > 8) 126 num_to_check = 8; 127 else if (num_to_check < 1) 128 return (-1); 129 130 if (start > 7) 131 return (-1); 132 133 if (start + num_to_check > 8) 134 num_to_check = 8 - start; 135 136 return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check))); 137 } 138 139 #if defined(PNG_1_0_X) || defined(PNG_1_2_X) 140 /* (Obsolete) function to check signature bytes. It does not allow one 141 * to check a partial signature. This function might be removed in the 142 * future - use png_sig_cmp(). Returns true (nonzero) if the file is PNG. 143 */ 144 int PNGAPI 145 png_check_sig(png_bytep sig, int num) 146 { 147 return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num)); 148 } 149 #endif 150 #endif /* PNG_READ_SUPPORTED */ 151 152 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 153 /* Function to allocate memory for zlib and clear it to 0. */ 154 #ifdef PNG_1_0_X 155 voidpf PNGAPI 156 #else 157 voidpf /* PRIVATE */ 158 #endif 159 png_zalloc(voidpf png_ptr, uInt items, uInt size) 160 { 161 png_voidp ptr; 162 png_structp p=(png_structp)png_ptr; 163 png_uint_32 save_flags=p->flags; 164 png_uint_32 num_bytes; 165 166 if (png_ptr == NULL) 167 return (NULL); 168 if (items > PNG_UINT_32_MAX/size) 169 { 170 png_warning (p, "Potential overflow in png_zalloc()"); 171 return (NULL); 172 } 173 num_bytes = (png_uint_32)items * size; 174 175 p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK; 176 ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes); 177 p->flags=save_flags; 178 179 #if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO) 180 if (ptr == NULL) 181 return ((voidpf)ptr); 182 183 if (num_bytes > (png_uint_32)0x8000L) 184 { 185 png_memset(ptr, 0, (png_size_t)0x8000L); 186 png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0, 187 (png_size_t)(num_bytes - (png_uint_32)0x8000L)); 188 } 189 else 190 { 191 png_memset(ptr, 0, (png_size_t)num_bytes); 192 } 193 #endif 194 return ((voidpf)ptr); 195 } 196 197 /* Function to free memory for zlib */ 198 #ifdef PNG_1_0_X 199 void PNGAPI 200 #else 201 void /* PRIVATE */ 202 #endif 203 png_zfree(voidpf png_ptr, voidpf ptr) 204 { 205 png_free((png_structp)png_ptr, (png_voidp)ptr); 206 } 207 208 /* Reset the CRC variable to 32 bits of 1's. Care must be taken 209 * in case CRC is > 32 bits to leave the top bits 0. 210 */ 211 void /* PRIVATE */ 212 png_reset_crc(png_structp png_ptr) 213 { 214 png_ptr->crc = crc32(0, Z_NULL, 0); 215 } 216 217 /* Calculate the CRC over a section of data. We can only pass as 218 * much data to this routine as the largest single buffer size. We 219 * also check that this data will actually be used before going to the 220 * trouble of calculating it. 221 */ 222 void /* PRIVATE */ 223 png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length) 224 { 225 int need_crc = 1; 226 227 if (png_ptr->chunk_name[0] & 0x20) /* ancillary */ 228 { 229 if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == 230 (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) 231 need_crc = 0; 232 } 233 else /* critical */ 234 { 235 if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) 236 need_crc = 0; 237 } 238 239 if (need_crc) 240 png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length); 241 } 242 243 /* Allocate the memory for an info_struct for the application. We don't 244 * really need the png_ptr, but it could potentially be useful in the 245 * future. This should be used in favour of malloc(png_sizeof(png_info)) 246 * and png_info_init() so that applications that want to use a shared 247 * libpng don't have to be recompiled if png_info changes size. 248 */ 249 png_infop PNGAPI 250 png_create_info_struct(png_structp png_ptr) 251 { 252 png_infop info_ptr; 253 254 png_debug(1, "in png_create_info_struct"); 255 256 if (png_ptr == NULL) 257 return (NULL); 258 259 #ifdef PNG_USER_MEM_SUPPORTED 260 info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO, 261 png_ptr->malloc_fn, png_ptr->mem_ptr); 262 #else 263 info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); 264 #endif 265 if (info_ptr != NULL) 266 png_info_init_3(&info_ptr, png_sizeof(png_info)); 267 268 return (info_ptr); 269 } 270 271 /* This function frees the memory associated with a single info struct. 272 * Normally, one would use either png_destroy_read_struct() or 273 * png_destroy_write_struct() to free an info struct, but this may be 274 * useful for some applications. 275 */ 276 void PNGAPI 277 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr) 278 { 279 png_infop info_ptr = NULL; 280 281 png_debug(1, "in png_destroy_info_struct"); 282 283 if (png_ptr == NULL) 284 return; 285 286 if (info_ptr_ptr != NULL) 287 info_ptr = *info_ptr_ptr; 288 289 if (info_ptr != NULL) 290 { 291 png_info_destroy(png_ptr, info_ptr); 292 293 #ifdef PNG_USER_MEM_SUPPORTED 294 png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn, 295 png_ptr->mem_ptr); 296 #else 297 png_destroy_struct((png_voidp)info_ptr); 298 #endif 299 *info_ptr_ptr = NULL; 300 } 301 } 302 303 /* Initialize the info structure. This is now an internal function (0.89) 304 * and applications using it are urged to use png_create_info_struct() 305 * instead. 306 */ 307 #if defined(PNG_1_0_X) || defined(PNG_1_2_X) 308 #undef png_info_init 309 void PNGAPI 310 png_info_init(png_infop info_ptr) 311 { 312 /* We only come here via pre-1.0.12-compiled applications */ 313 png_info_init_3(&info_ptr, 0); 314 } 315 #endif 316 317 void PNGAPI 318 png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size) 319 { 320 png_infop info_ptr = *ptr_ptr; 321 322 png_debug(1, "in png_info_init_3"); 323 324 if (info_ptr == NULL) 325 return; 326 327 if (png_sizeof(png_info) > png_info_struct_size) 328 { 329 png_destroy_struct(info_ptr); 330 info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO); 331 *ptr_ptr = info_ptr; 332 } 333 334 /* Set everything to 0 */ 335 png_memset(info_ptr, 0, png_sizeof(png_info)); 336 } 337 338 #ifdef PNG_FREE_ME_SUPPORTED 339 void PNGAPI 340 png_data_freer(png_structp png_ptr, png_infop info_ptr, 341 int freer, png_uint_32 mask) 342 { 343 png_debug(1, "in png_data_freer"); 344 345 if (png_ptr == NULL || info_ptr == NULL) 346 return; 347 348 if (freer == PNG_DESTROY_WILL_FREE_DATA) 349 info_ptr->free_me |= mask; 350 else if (freer == PNG_USER_WILL_FREE_DATA) 351 info_ptr->free_me &= ~mask; 352 else 353 png_warning(png_ptr, 354 "Unknown freer parameter in png_data_freer."); 355 } 356 #endif 357 358 void PNGAPI 359 png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask, 360 int num) 361 { 362 png_debug(1, "in png_free_data"); 363 364 if (png_ptr == NULL || info_ptr == NULL) 365 return; 366 367 #ifdef PNG_TEXT_SUPPORTED 368 /* Free text item num or (if num == -1) all text items */ 369 #ifdef PNG_FREE_ME_SUPPORTED 370 if ((mask & PNG_FREE_TEXT) & info_ptr->free_me) 371 #else 372 if (mask & PNG_FREE_TEXT) 373 #endif 374 { 375 if (num != -1) 376 { 377 if (info_ptr->text && info_ptr->text[num].key) 378 { 379 png_free(png_ptr, info_ptr->text[num].key); 380 info_ptr->text[num].key = NULL; 381 } 382 } 383 else 384 { 385 int i; 386 for (i = 0; i < info_ptr->num_text; i++) 387 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i); 388 png_free(png_ptr, info_ptr->text); 389 info_ptr->text = NULL; 390 info_ptr->num_text=0; 391 } 392 } 393 #endif 394 395 #ifdef PNG_tRNS_SUPPORTED 396 /* Free any tRNS entry */ 397 #ifdef PNG_FREE_ME_SUPPORTED 398 if ((mask & PNG_FREE_TRNS) & info_ptr->free_me) 399 #else 400 if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS)) 401 #endif 402 { 403 png_free(png_ptr, info_ptr->trans); 404 info_ptr->trans = NULL; 405 info_ptr->valid &= ~PNG_INFO_tRNS; 406 #ifndef PNG_FREE_ME_SUPPORTED 407 png_ptr->flags &= ~PNG_FLAG_FREE_TRNS; 408 #endif 409 } 410 #endif 411 412 #ifdef PNG_sCAL_SUPPORTED 413 /* Free any sCAL entry */ 414 #ifdef PNG_FREE_ME_SUPPORTED 415 if ((mask & PNG_FREE_SCAL) & info_ptr->free_me) 416 #else 417 if (mask & PNG_FREE_SCAL) 418 #endif 419 { 420 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED) 421 png_free(png_ptr, info_ptr->scal_s_width); 422 png_free(png_ptr, info_ptr->scal_s_height); 423 info_ptr->scal_s_width = NULL; 424 info_ptr->scal_s_height = NULL; 425 #endif 426 info_ptr->valid &= ~PNG_INFO_sCAL; 427 } 428 #endif 429 430 #ifdef PNG_pCAL_SUPPORTED 431 /* Free any pCAL entry */ 432 #ifdef PNG_FREE_ME_SUPPORTED 433 if ((mask & PNG_FREE_PCAL) & info_ptr->free_me) 434 #else 435 if (mask & PNG_FREE_PCAL) 436 #endif 437 { 438 png_free(png_ptr, info_ptr->pcal_purpose); 439 png_free(png_ptr, info_ptr->pcal_units); 440 info_ptr->pcal_purpose = NULL; 441 info_ptr->pcal_units = NULL; 442 if (info_ptr->pcal_params != NULL) 443 { 444 int i; 445 for (i = 0; i < (int)info_ptr->pcal_nparams; i++) 446 { 447 png_free(png_ptr, info_ptr->pcal_params[i]); 448 info_ptr->pcal_params[i] = NULL; 449 } 450 png_free(png_ptr, info_ptr->pcal_params); 451 info_ptr->pcal_params = NULL; 452 } 453 info_ptr->valid &= ~PNG_INFO_pCAL; 454 } 455 #endif 456 457 #ifdef PNG_iCCP_SUPPORTED 458 /* Free any iCCP entry */ 459 #ifdef PNG_FREE_ME_SUPPORTED 460 if ((mask & PNG_FREE_ICCP) & info_ptr->free_me) 461 #else 462 if (mask & PNG_FREE_ICCP) 463 #endif 464 { 465 png_free(png_ptr, info_ptr->iccp_name); 466 png_free(png_ptr, info_ptr->iccp_profile); 467 info_ptr->iccp_name = NULL; 468 info_ptr->iccp_profile = NULL; 469 info_ptr->valid &= ~PNG_INFO_iCCP; 470 } 471 #endif 472 473 #ifdef PNG_sPLT_SUPPORTED 474 /* Free a given sPLT entry, or (if num == -1) all sPLT entries */ 475 #ifdef PNG_FREE_ME_SUPPORTED 476 if ((mask & PNG_FREE_SPLT) & info_ptr->free_me) 477 #else 478 if (mask & PNG_FREE_SPLT) 479 #endif 480 { 481 if (num != -1) 482 { 483 if (info_ptr->splt_palettes) 484 { 485 png_free(png_ptr, info_ptr->splt_palettes[num].name); 486 png_free(png_ptr, info_ptr->splt_palettes[num].entries); 487 info_ptr->splt_palettes[num].name = NULL; 488 info_ptr->splt_palettes[num].entries = NULL; 489 } 490 } 491 else 492 { 493 if (info_ptr->splt_palettes_num) 494 { 495 int i; 496 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++) 497 png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i); 498 499 png_free(png_ptr, info_ptr->splt_palettes); 500 info_ptr->splt_palettes = NULL; 501 info_ptr->splt_palettes_num = 0; 502 } 503 info_ptr->valid &= ~PNG_INFO_sPLT; 504 } 505 } 506 #endif 507 508 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED 509 if (png_ptr->unknown_chunk.data) 510 { 511 png_free(png_ptr, png_ptr->unknown_chunk.data); 512 png_ptr->unknown_chunk.data = NULL; 513 } 514 515 #ifdef PNG_FREE_ME_SUPPORTED 516 if ((mask & PNG_FREE_UNKN) & info_ptr->free_me) 517 #else 518 if (mask & PNG_FREE_UNKN) 519 #endif 520 { 521 if (num != -1) 522 { 523 if (info_ptr->unknown_chunks) 524 { 525 png_free(png_ptr, info_ptr->unknown_chunks[num].data); 526 info_ptr->unknown_chunks[num].data = NULL; 527 } 528 } 529 else 530 { 531 int i; 532 533 if (info_ptr->unknown_chunks_num) 534 { 535 for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++) 536 png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i); 537 538 png_free(png_ptr, info_ptr->unknown_chunks); 539 info_ptr->unknown_chunks = NULL; 540 info_ptr->unknown_chunks_num = 0; 541 } 542 } 543 } 544 #endif 545 546 #ifdef PNG_hIST_SUPPORTED 547 /* Free any hIST entry */ 548 #ifdef PNG_FREE_ME_SUPPORTED 549 if ((mask & PNG_FREE_HIST) & info_ptr->free_me) 550 #else 551 if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST)) 552 #endif 553 { 554 png_free(png_ptr, info_ptr->hist); 555 info_ptr->hist = NULL; 556 info_ptr->valid &= ~PNG_INFO_hIST; 557 #ifndef PNG_FREE_ME_SUPPORTED 558 png_ptr->flags &= ~PNG_FLAG_FREE_HIST; 559 #endif 560 } 561 #endif 562 563 /* Free any PLTE entry that was internally allocated */ 564 #ifdef PNG_FREE_ME_SUPPORTED 565 if ((mask & PNG_FREE_PLTE) & info_ptr->free_me) 566 #else 567 if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE)) 568 #endif 569 { 570 png_zfree(png_ptr, info_ptr->palette); 571 info_ptr->palette = NULL; 572 info_ptr->valid &= ~PNG_INFO_PLTE; 573 #ifndef PNG_FREE_ME_SUPPORTED 574 png_ptr->flags &= ~PNG_FLAG_FREE_PLTE; 575 #endif 576 info_ptr->num_palette = 0; 577 } 578 579 #ifdef PNG_INFO_IMAGE_SUPPORTED 580 /* Free any image bits attached to the info structure */ 581 #ifdef PNG_FREE_ME_SUPPORTED 582 if ((mask & PNG_FREE_ROWS) & info_ptr->free_me) 583 #else 584 if (mask & PNG_FREE_ROWS) 585 #endif 586 { 587 if (info_ptr->row_pointers) 588 { 589 int row; 590 for (row = 0; row < (int)info_ptr->height; row++) 591 { 592 png_free(png_ptr, info_ptr->row_pointers[row]); 593 info_ptr->row_pointers[row] = NULL; 594 } 595 png_free(png_ptr, info_ptr->row_pointers); 596 info_ptr->row_pointers = NULL; 597 } 598 info_ptr->valid &= ~PNG_INFO_IDAT; 599 } 600 #endif 601 602 #ifdef PNG_FREE_ME_SUPPORTED 603 if (num == -1) 604 info_ptr->free_me &= ~mask; 605 else 606 info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL); 607 #endif 608 } 609 610 /* This is an internal routine to free any memory that the info struct is 611 * pointing to before re-using it or freeing the struct itself. Recall 612 * that png_free() checks for NULL pointers for us. 613 */ 614 void /* PRIVATE */ 615 png_info_destroy(png_structp png_ptr, png_infop info_ptr) 616 { 617 png_debug(1, "in png_info_destroy"); 618 619 png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); 620 621 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 622 if (png_ptr->num_chunk_list) 623 { 624 png_free(png_ptr, png_ptr->chunk_list); 625 png_ptr->chunk_list = NULL; 626 png_ptr->num_chunk_list = 0; 627 } 628 #endif 629 630 png_info_init_3(&info_ptr, png_sizeof(png_info)); 631 } 632 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 633 634 /* This function returns a pointer to the io_ptr associated with the user 635 * functions. The application should free any memory associated with this 636 * pointer before png_write_destroy() or png_read_destroy() are called. 637 */ 638 png_voidp PNGAPI 639 png_get_io_ptr(png_structp png_ptr) 640 { 641 if (png_ptr == NULL) 642 return (NULL); 643 return (png_ptr->io_ptr); 644 } 645 646 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 647 #ifdef PNG_STDIO_SUPPORTED 648 /* Initialize the default input/output functions for the PNG file. If you 649 * use your own read or write routines, you can call either png_set_read_fn() 650 * or png_set_write_fn() instead of png_init_io(). If you have defined 651 * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't 652 * necessarily available. 653 */ 654 void PNGAPI 655 png_init_io(png_structp png_ptr, png_FILE_p fp) 656 { 657 png_debug(1, "in png_init_io"); 658 659 if (png_ptr == NULL) 660 return; 661 662 png_ptr->io_ptr = (png_voidp)fp; 663 } 664 #endif 665 666 #ifdef PNG_TIME_RFC1123_SUPPORTED 667 /* Convert the supplied time into an RFC 1123 string suitable for use in 668 * a "Creation Time" or other text-based time string. 669 */ 670 png_charp PNGAPI 671 png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime) 672 { 673 static PNG_CONST char short_months[12][4] = 674 {"Jan", "Feb", "Mar", "Apr", "May", "Jun", 675 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; 676 677 if (png_ptr == NULL) 678 return (NULL); 679 if (png_ptr->time_buffer == NULL) 680 { 681 png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29* 682 png_sizeof(char))); 683 } 684 685 #ifdef _WIN32_WCE 686 { 687 wchar_t time_buf[29]; 688 wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"), 689 ptime->day % 32, short_months[(ptime->month - 1) % 12], 690 ptime->year, ptime->hour % 24, ptime->minute % 60, 691 ptime->second % 61); 692 WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 693 29, NULL, NULL); 694 } 695 #else 696 #ifdef USE_FAR_KEYWORD 697 { 698 char near_time_buf[29]; 699 png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000", 700 ptime->day % 32, short_months[(ptime->month - 1) % 12], 701 ptime->year, ptime->hour % 24, ptime->minute % 60, 702 ptime->second % 61); 703 png_memcpy(png_ptr->time_buffer, near_time_buf, 704 29*png_sizeof(char)); 705 } 706 #else 707 png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000", 708 ptime->day % 32, short_months[(ptime->month - 1) % 12], 709 ptime->year, ptime->hour % 24, ptime->minute % 60, 710 ptime->second % 61); 711 #endif 712 #endif /* _WIN32_WCE */ 713 return ((png_charp)png_ptr->time_buffer); 714 } 715 #endif /* PNG_TIME_RFC1123_SUPPORTED */ 716 717 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 718 719 png_charp PNGAPI 720 png_get_copyright(png_structp png_ptr) 721 { 722 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 723 #ifdef PNG_STRING_COPYRIGHT 724 return PNG_STRING_COPYRIGHT 725 #else 726 #ifdef __STDC__ 727 return ((png_charp) PNG_STRING_NEWLINE \ 728 "libpng version 1.2.46 - July 9, 2011" PNG_STRING_NEWLINE \ 729 "Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ 730 "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ 731 "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ 732 PNG_STRING_NEWLINE); 733 #else 734 return ((png_charp) "libpng version 1.2.46 - July 9, 2011\ 735 Copyright (c) 1998-2011 Glenn Randers-Pehrson\ 736 Copyright (c) 1996-1997 Andreas Dilger\ 737 Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."); 738 #endif 739 #endif 740 } 741 742 /* The following return the library version as a short string in the 743 * format 1.0.0 through 99.99.99zz. To get the version of *.h files 744 * used with your application, print out PNG_LIBPNG_VER_STRING, which 745 * is defined in png.h. 746 * Note: now there is no difference between png_get_libpng_ver() and 747 * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard, 748 * it is guaranteed that png.c uses the correct version of png.h. 749 */ 750 png_charp PNGAPI 751 png_get_libpng_ver(png_structp png_ptr) 752 { 753 /* Version of *.c files used when building libpng */ 754 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 755 return ((png_charp) PNG_LIBPNG_VER_STRING); 756 } 757 758 png_charp PNGAPI 759 png_get_header_ver(png_structp png_ptr) 760 { 761 /* Version of *.h files used when building libpng */ 762 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 763 return ((png_charp) PNG_LIBPNG_VER_STRING); 764 } 765 766 png_charp PNGAPI 767 png_get_header_version(png_structp png_ptr) 768 { 769 /* Returns longer string containing both version and date */ 770 png_ptr = png_ptr; /* Silence compiler warning about unused png_ptr */ 771 #ifdef __STDC__ 772 return ((png_charp) PNG_HEADER_VERSION_STRING 773 #ifndef PNG_READ_SUPPORTED 774 " (NO READ SUPPORT)" 775 #endif 776 PNG_STRING_NEWLINE); 777 #else 778 return ((png_charp) PNG_HEADER_VERSION_STRING); 779 #endif 780 } 781 782 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 783 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 784 int PNGAPI 785 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name) 786 { 787 /* Check chunk_name and return "keep" value if it's on the list, else 0 */ 788 int i; 789 png_bytep p; 790 if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0) 791 return 0; 792 p = png_ptr->chunk_list + png_ptr->num_chunk_list*5 - 5; 793 for (i = png_ptr->num_chunk_list; i; i--, p -= 5) 794 if (!png_memcmp(chunk_name, p, 4)) 795 return ((int)*(p + 4)); 796 return 0; 797 } 798 #endif 799 800 /* This function, added to libpng-1.0.6g, is untested. */ 801 int PNGAPI 802 png_reset_zstream(png_structp png_ptr) 803 { 804 if (png_ptr == NULL) 805 return Z_STREAM_ERROR; 806 return (inflateReset(&png_ptr->zstream)); 807 } 808 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 809 810 /* This function was added to libpng-1.0.7 */ 811 png_uint_32 PNGAPI 812 png_access_version_number(void) 813 { 814 /* Version of *.c files used when building libpng */ 815 return((png_uint_32) PNG_LIBPNG_VER); 816 } 817 818 819 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED) 820 #ifndef PNG_1_0_X 821 /* This function was added to libpng 1.2.0 */ 822 int PNGAPI 823 png_mmx_support(void) 824 { 825 /* Obsolete, to be removed from libpng-1.4.0 */ 826 return -1; 827 } 828 #endif /* PNG_1_0_X */ 829 #endif /* PNG_READ_SUPPORTED && PNG_ASSEMBLER_CODE_SUPPORTED */ 830 831 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) 832 #ifdef PNG_SIZE_T 833 /* Added at libpng version 1.2.6 */ 834 PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size)); 835 png_size_t PNGAPI 836 png_convert_size(size_t size) 837 { 838 if (size > (png_size_t)-1) 839 PNG_ABORT(); /* We haven't got access to png_ptr, so no png_error() */ 840 return ((png_size_t)size); 841 } 842 #endif /* PNG_SIZE_T */ 843 844 /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ 845 #ifdef PNG_cHRM_SUPPORTED 846 #ifdef PNG_CHECK_cHRM_SUPPORTED 847 848 void /* PRIVATE */ 849 png_64bit_product (long v1, long v2, unsigned long *hi_product, 850 unsigned long *lo_product) 851 { 852 int64_t x = (int64_t)v1 * (int64_t)v2; 853 *hi_product = (unsigned long) (x >> 32); 854 *lo_product = (unsigned long) x; 855 } 856 857 int /* PRIVATE */ 858 png_check_cHRM_fixed(png_structp png_ptr, 859 png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x, 860 png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y, 861 png_fixed_point blue_x, png_fixed_point blue_y) 862 { 863 int ret = 1; 864 unsigned long xy_hi,xy_lo,yx_hi,yx_lo; 865 866 png_debug(1, "in function png_check_cHRM_fixed"); 867 868 if (png_ptr == NULL) 869 return 0; 870 871 if (white_x < 0 || white_y <= 0 || 872 red_x < 0 || red_y < 0 || 873 green_x < 0 || green_y < 0 || 874 blue_x < 0 || blue_y < 0) 875 { 876 png_warning(png_ptr, 877 "Ignoring attempt to set negative chromaticity value"); 878 ret = 0; 879 } 880 if (white_x > (png_fixed_point) PNG_UINT_31_MAX || 881 white_y > (png_fixed_point) PNG_UINT_31_MAX || 882 red_x > (png_fixed_point) PNG_UINT_31_MAX || 883 red_y > (png_fixed_point) PNG_UINT_31_MAX || 884 green_x > (png_fixed_point) PNG_UINT_31_MAX || 885 green_y > (png_fixed_point) PNG_UINT_31_MAX || 886 blue_x > (png_fixed_point) PNG_UINT_31_MAX || 887 blue_y > (png_fixed_point) PNG_UINT_31_MAX ) 888 { 889 png_warning(png_ptr, 890 "Ignoring attempt to set chromaticity value exceeding 21474.83"); 891 ret = 0; 892 } 893 if (white_x > 100000L - white_y) 894 { 895 png_warning(png_ptr, "Invalid cHRM white point"); 896 ret = 0; 897 } 898 if (red_x > 100000L - red_y) 899 { 900 png_warning(png_ptr, "Invalid cHRM red point"); 901 ret = 0; 902 } 903 if (green_x > 100000L - green_y) 904 { 905 png_warning(png_ptr, "Invalid cHRM green point"); 906 ret = 0; 907 } 908 if (blue_x > 100000L - blue_y) 909 { 910 png_warning(png_ptr, "Invalid cHRM blue point"); 911 ret = 0; 912 } 913 914 png_64bit_product(green_x - red_x, blue_y - red_y, &xy_hi, &xy_lo); 915 png_64bit_product(green_y - red_y, blue_x - red_x, &yx_hi, &yx_lo); 916 917 if (xy_hi == yx_hi && xy_lo == yx_lo) 918 { 919 png_warning(png_ptr, 920 "Ignoring attempt to set cHRM RGB triangle with zero area"); 921 ret = 0; 922 } 923 924 return ret; 925 } 926 #endif /* PNG_CHECK_cHRM_SUPPORTED */ 927 #endif /* PNG_cHRM_SUPPORTED */ 928 929 void /* PRIVATE */ 930 png_check_IHDR(png_structp png_ptr, 931 png_uint_32 width, png_uint_32 height, int bit_depth, 932 int color_type, int interlace_type, int compression_type, 933 int filter_type) 934 { 935 int error = 0; 936 937 /* Check for width and height valid values */ 938 if (width == 0) 939 { 940 png_warning(png_ptr, "Image width is zero in IHDR"); 941 error = 1; 942 } 943 944 if (height == 0) 945 { 946 png_warning(png_ptr, "Image height is zero in IHDR"); 947 error = 1; 948 } 949 950 #ifdef PNG_SET_USER_LIMITS_SUPPORTED 951 if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX) 952 #else 953 if (width > PNG_USER_WIDTH_MAX) 954 #endif 955 { 956 png_warning(png_ptr, "Image width exceeds user limit in IHDR"); 957 error = 1; 958 } 959 960 #ifdef PNG_SET_USER_LIMITS_SUPPORTED 961 if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX) 962 #else 963 if (height > PNG_USER_HEIGHT_MAX) 964 #endif 965 { 966 png_warning(png_ptr, "Image height exceeds user limit in IHDR"); 967 error = 1; 968 } 969 970 if (width > PNG_UINT_31_MAX) 971 { 972 png_warning(png_ptr, "Invalid image width in IHDR"); 973 error = 1; 974 } 975 976 if ( height > PNG_UINT_31_MAX) 977 { 978 png_warning(png_ptr, "Invalid image height in IHDR"); 979 error = 1; 980 } 981 982 if ( width > (PNG_UINT_32_MAX 983 >> 3) /* 8-byte RGBA pixels */ 984 - 64 /* bigrowbuf hack */ 985 - 1 /* filter byte */ 986 - 7*8 /* rounding of width to multiple of 8 pixels */ 987 - 8) /* extra max_pixel_depth pad */ 988 png_warning(png_ptr, "Width is too large for libpng to process pixels"); 989 990 /* Check other values */ 991 if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && 992 bit_depth != 8 && bit_depth != 16) 993 { 994 png_warning(png_ptr, "Invalid bit depth in IHDR"); 995 error = 1; 996 } 997 998 if (color_type < 0 || color_type == 1 || 999 color_type == 5 || color_type > 6) 1000 { 1001 png_warning(png_ptr, "Invalid color type in IHDR"); 1002 error = 1; 1003 } 1004 1005 if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) || 1006 ((color_type == PNG_COLOR_TYPE_RGB || 1007 color_type == PNG_COLOR_TYPE_GRAY_ALPHA || 1008 color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8)) 1009 { 1010 png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR"); 1011 error = 1; 1012 } 1013 1014 if (interlace_type >= PNG_INTERLACE_LAST) 1015 { 1016 png_warning(png_ptr, "Unknown interlace method in IHDR"); 1017 error = 1; 1018 } 1019 1020 if (compression_type != PNG_COMPRESSION_TYPE_BASE) 1021 { 1022 png_warning(png_ptr, "Unknown compression method in IHDR"); 1023 error = 1; 1024 } 1025 1026 #ifdef PNG_MNG_FEATURES_SUPPORTED 1027 /* Accept filter_method 64 (intrapixel differencing) only if 1028 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and 1029 * 2. Libpng did not read a PNG signature (this filter_method is only 1030 * used in PNG datastreams that are embedded in MNG datastreams) and 1031 * 3. The application called png_permit_mng_features with a mask that 1032 * included PNG_FLAG_MNG_FILTER_64 and 1033 * 4. The filter_method is 64 and 1034 * 5. The color_type is RGB or RGBA 1035 */ 1036 if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) && 1037 png_ptr->mng_features_permitted) 1038 png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); 1039 1040 if (filter_type != PNG_FILTER_TYPE_BASE) 1041 { 1042 if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && 1043 (filter_type == PNG_INTRAPIXEL_DIFFERENCING) && 1044 ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && 1045 (color_type == PNG_COLOR_TYPE_RGB || 1046 color_type == PNG_COLOR_TYPE_RGB_ALPHA))) 1047 { 1048 png_warning(png_ptr, "Unknown filter method in IHDR"); 1049 error = 1; 1050 } 1051 1052 if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) 1053 { 1054 png_warning(png_ptr, "Invalid filter method in IHDR"); 1055 error = 1; 1056 } 1057 } 1058 1059 #else 1060 if (filter_type != PNG_FILTER_TYPE_BASE) 1061 { 1062 png_warning(png_ptr, "Unknown filter method in IHDR"); 1063 error = 1; 1064 } 1065 #endif 1066 1067 if (error == 1) 1068 png_error(png_ptr, "Invalid IHDR data"); 1069 } 1070 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ 1071
