1 2/* pngread.c - read a PNG file 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 * This file contains routines that an application calls directly to 14 * read a PNG file or stream. 15 */ 16 17#define PNG_INTERNAL 18#define PNG_NO_PEDANTIC_WARNINGS 19#include "png.h" 20#ifdef PNG_READ_SUPPORTED 21 22 23/* Create a PNG structure for reading, and allocate any memory needed. */ 24png_structp PNGAPI 25png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr, 26 png_error_ptr error_fn, png_error_ptr warn_fn) 27{ 28 29#ifdef PNG_USER_MEM_SUPPORTED 30 return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn, 31 warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL)); 32} 33 34/* Alternate create PNG structure for reading, and allocate any memory 35 * needed. 36 */ 37png_structp PNGAPI 38png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr, 39 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, 40 png_malloc_ptr malloc_fn, png_free_ptr free_fn) 41{ 42#endif /* PNG_USER_MEM_SUPPORTED */ 43 44#ifdef PNG_SETJMP_SUPPORTED 45 volatile 46#endif 47 png_structp png_ptr; 48 49#ifdef PNG_SETJMP_SUPPORTED 50#ifdef USE_FAR_KEYWORD 51 jmp_buf jmpbuf; 52#endif 53#endif 54 55 int i; 56 57 png_debug(1, "in png_create_read_struct"); 58 59#ifdef PNG_USER_MEM_SUPPORTED 60 png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG, 61 (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr); 62#else 63 png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG); 64#endif 65 if (png_ptr == NULL) 66 return (NULL); 67 68 /* Added at libpng-1.2.6 */ 69#ifdef PNG_USER_LIMITS_SUPPORTED 70 png_ptr->user_width_max = PNG_USER_WIDTH_MAX; 71 png_ptr->user_height_max = PNG_USER_HEIGHT_MAX; 72# ifdef PNG_USER_CHUNK_CACHE_MAX 73 /* Added at libpng-1.2.43 and 1.4.0 */ 74 png_ptr->user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX; 75# endif 76# ifdef PNG_SET_USER_CHUNK_MALLOC_MAX 77 /* Added at libpng-1.2.43 and 1.4.1 */ 78 png_ptr->user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX; 79# endif 80#endif 81 82#ifdef PNG_SETJMP_SUPPORTED 83#ifdef USE_FAR_KEYWORD 84 if (setjmp(jmpbuf)) 85#else 86 if (setjmp(png_ptr->jmpbuf)) 87#endif 88 { 89 png_free(png_ptr, png_ptr->zbuf); 90 png_ptr->zbuf = NULL; 91#ifdef PNG_USER_MEM_SUPPORTED 92 png_destroy_struct_2((png_voidp)png_ptr, 93 (png_free_ptr)free_fn, (png_voidp)mem_ptr); 94#else 95 png_destroy_struct((png_voidp)png_ptr); 96#endif 97 return (NULL); 98 } 99#ifdef USE_FAR_KEYWORD 100 png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf)); 101#endif 102#endif /* PNG_SETJMP_SUPPORTED */ 103 104#ifdef PNG_USER_MEM_SUPPORTED 105 png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn); 106#endif 107 108 png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn); 109 110 if (user_png_ver) 111 { 112 i = 0; 113 do 114 { 115 if (user_png_ver[i] != png_libpng_ver[i]) 116 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; 117 } while (png_libpng_ver[i++]); 118 } 119 else 120 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; 121 122 123 if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) 124 { 125 /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so 126 * we must recompile any applications that use any older library version. 127 * For versions after libpng 1.0, we will be compatible, so we need 128 * only check the first digit. 129 */ 130 if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] || 131 (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) || 132 (user_png_ver[0] == '0' && user_png_ver[2] < '9')) 133 { 134#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE) 135 char msg[80]; 136 if (user_png_ver) 137 { 138 png_snprintf(msg, 80, 139 "Application was compiled with png.h from libpng-%.20s", 140 user_png_ver); 141 png_warning(png_ptr, msg); 142 } 143 png_snprintf(msg, 80, 144 "Application is running with png.c from libpng-%.20s", 145 png_libpng_ver); 146 png_warning(png_ptr, msg); 147#endif 148#ifdef PNG_ERROR_NUMBERS_SUPPORTED 149 png_ptr->flags = 0; 150#endif 151 png_error(png_ptr, 152 "Incompatible libpng version in application and library"); 153 } 154 } 155 156 /* Initialize zbuf - compression buffer */ 157 png_ptr->zbuf_size = PNG_ZBUF_SIZE; 158 png_ptr->zbuf = (png_bytep)png_malloc(png_ptr, 159 (png_uint_32)png_ptr->zbuf_size); 160 png_ptr->zstream.zalloc = png_zalloc; 161 png_ptr->zstream.zfree = png_zfree; 162 png_ptr->zstream.opaque = (voidpf)png_ptr; 163 164 switch (inflateInit(&png_ptr->zstream)) 165 { 166 case Z_OK: /* Do nothing */ break; 167 case Z_MEM_ERROR: 168 case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); 169 break; 170 case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); 171 break; 172 default: png_error(png_ptr, "Unknown zlib error"); 173 } 174 175 176 png_ptr->zstream.next_out = png_ptr->zbuf; 177 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; 178 179 png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL); 180 181#ifdef PNG_SETJMP_SUPPORTED 182/* Applications that neglect to set up their own setjmp() and then 183 encounter a png_error() will longjmp here. Since the jmpbuf is 184 then meaningless we abort instead of returning. */ 185#ifdef USE_FAR_KEYWORD 186 if (setjmp(jmpbuf)) 187 PNG_ABORT(); 188 png_memcpy(png_ptr->jmpbuf, jmpbuf, png_sizeof(jmp_buf)); 189#else 190 if (setjmp(png_ptr->jmpbuf)) 191 PNG_ABORT(); 192#endif 193#endif /* PNG_SETJMP_SUPPORTED */ 194 195#ifdef PNG_INDEX_SUPPORTED 196 png_ptr->index = NULL; 197#endif 198 199 return (png_ptr); 200} 201 202#if defined(PNG_1_0_X) || defined(PNG_1_2_X) 203/* Initialize PNG structure for reading, and allocate any memory needed. 204 * This interface is deprecated in favour of the png_create_read_struct(), 205 * and it will disappear as of libpng-1.3.0. 206 */ 207#undef png_read_init 208void PNGAPI 209png_read_init(png_structp png_ptr) 210{ 211 /* We only come here via pre-1.0.7-compiled applications */ 212 png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0); 213} 214 215void PNGAPI 216png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver, 217 png_size_t png_struct_size, png_size_t png_info_size) 218{ 219 /* We only come here via pre-1.0.12-compiled applications */ 220 if (png_ptr == NULL) 221 return; 222#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE) 223 if (png_sizeof(png_struct) > png_struct_size || 224 png_sizeof(png_info) > png_info_size) 225 { 226 char msg[80]; 227 png_ptr->warning_fn = NULL; 228 if (user_png_ver) 229 { 230 png_snprintf(msg, 80, 231 "Application was compiled with png.h from libpng-%.20s", 232 user_png_ver); 233 png_warning(png_ptr, msg); 234 } 235 png_snprintf(msg, 80, 236 "Application is running with png.c from libpng-%.20s", 237 png_libpng_ver); 238 png_warning(png_ptr, msg); 239 } 240#endif 241 if (png_sizeof(png_struct) > png_struct_size) 242 { 243 png_ptr->error_fn = NULL; 244#ifdef PNG_ERROR_NUMBERS_SUPPORTED 245 png_ptr->flags = 0; 246#endif 247 png_error(png_ptr, 248 "The png struct allocated by the application for reading is" 249 " too small."); 250 } 251 if (png_sizeof(png_info) > png_info_size) 252 { 253 png_ptr->error_fn = NULL; 254#ifdef PNG_ERROR_NUMBERS_SUPPORTED 255 png_ptr->flags = 0; 256#endif 257 png_error(png_ptr, 258 "The info struct allocated by application for reading is" 259 " too small."); 260 } 261 png_read_init_3(&png_ptr, user_png_ver, png_struct_size); 262} 263#endif /* PNG_1_0_X || PNG_1_2_X */ 264 265void PNGAPI 266png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver, 267 png_size_t png_struct_size) 268{ 269#ifdef PNG_SETJMP_SUPPORTED 270 jmp_buf tmp_jmp; /* to save current jump buffer */ 271#endif 272 273 int i = 0; 274 275 png_structp png_ptr=*ptr_ptr; 276 277 if (png_ptr == NULL) 278 return; 279 280 do 281 { 282 if (user_png_ver[i] != png_libpng_ver[i]) 283 { 284#ifdef PNG_LEGACY_SUPPORTED 285 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; 286#else 287 png_ptr->warning_fn = NULL; 288 png_warning(png_ptr, 289 "Application uses deprecated png_read_init() and should be" 290 " recompiled."); 291 break; 292#endif 293 } 294 } while (png_libpng_ver[i++]); 295 296 png_debug(1, "in png_read_init_3"); 297 298#ifdef PNG_SETJMP_SUPPORTED 299 /* Save jump buffer and error functions */ 300 png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf)); 301#endif 302 303 if (png_sizeof(png_struct) > png_struct_size) 304 { 305 png_destroy_struct(png_ptr); 306 *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG); 307 png_ptr = *ptr_ptr; 308 } 309 310 /* Reset all variables to 0 */ 311 png_memset(png_ptr, 0, png_sizeof(png_struct)); 312 313#ifdef PNG_SETJMP_SUPPORTED 314 /* Restore jump buffer */ 315 png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf)); 316#endif 317 318 /* Added at libpng-1.2.6 */ 319#ifdef PNG_SET_USER_LIMITS_SUPPORTED 320 png_ptr->user_width_max = PNG_USER_WIDTH_MAX; 321 png_ptr->user_height_max = PNG_USER_HEIGHT_MAX; 322#endif 323 324 /* Initialize zbuf - compression buffer */ 325 png_ptr->zbuf_size = PNG_ZBUF_SIZE; 326 png_ptr->zstream.zalloc = png_zalloc; 327 png_ptr->zbuf = (png_bytep)png_malloc(png_ptr, 328 (png_uint_32)png_ptr->zbuf_size); 329 png_ptr->zstream.zalloc = png_zalloc; 330 png_ptr->zstream.zfree = png_zfree; 331 png_ptr->zstream.opaque = (voidpf)png_ptr; 332 333 switch (inflateInit(&png_ptr->zstream)) 334 { 335 case Z_OK: /* Do nothing */ break; 336 case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break; 337 case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); 338 break; 339 default: png_error(png_ptr, "Unknown zlib error"); 340 } 341 342 png_ptr->zstream.next_out = png_ptr->zbuf; 343 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; 344 345 png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL); 346} 347 348#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 349/* Read the information before the actual image data. This has been 350 * changed in v0.90 to allow reading a file that already has the magic 351 * bytes read from the stream. You can tell libpng how many bytes have 352 * been read from the beginning of the stream (up to the maximum of 8) 353 * via png_set_sig_bytes(), and we will only check the remaining bytes 354 * here. The application can then have access to the signature bytes we 355 * read if it is determined that this isn't a valid PNG file. 356 */ 357void PNGAPI 358png_read_info(png_structp png_ptr, png_infop info_ptr) 359{ 360 png_debug(1, "in png_read_info"); 361 362 if (png_ptr == NULL || info_ptr == NULL) 363 return; 364 365 /* If we haven't checked all of the PNG signature bytes, do so now. */ 366 if (png_ptr->sig_bytes < 8) 367 { 368 png_size_t num_checked = png_ptr->sig_bytes, 369 num_to_check = 8 - num_checked; 370 371 png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); 372 png_ptr->sig_bytes = 8; 373 374 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) 375 { 376 if (num_checked < 4 && 377 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) 378 png_error(png_ptr, "Not a PNG file"); 379 else 380 png_error(png_ptr, "PNG file corrupted by ASCII conversion"); 381 } 382 if (num_checked < 3) 383 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; 384 } 385 386 for (;;) 387 { 388#ifdef PNG_USE_LOCAL_ARRAYS 389 PNG_CONST PNG_IHDR; 390 PNG_CONST PNG_IDAT; 391 PNG_CONST PNG_IEND; 392 PNG_CONST PNG_PLTE; 393#ifdef PNG_READ_bKGD_SUPPORTED 394 PNG_CONST PNG_bKGD; 395#endif 396#ifdef PNG_READ_cHRM_SUPPORTED 397 PNG_CONST PNG_cHRM; 398#endif 399#ifdef PNG_READ_gAMA_SUPPORTED 400 PNG_CONST PNG_gAMA; 401#endif 402#ifdef PNG_READ_hIST_SUPPORTED 403 PNG_CONST PNG_hIST; 404#endif 405#ifdef PNG_READ_iCCP_SUPPORTED 406 PNG_CONST PNG_iCCP; 407#endif 408#ifdef PNG_READ_iTXt_SUPPORTED 409 PNG_CONST PNG_iTXt; 410#endif 411#ifdef PNG_READ_oFFs_SUPPORTED 412 PNG_CONST PNG_oFFs; 413#endif 414#ifdef PNG_READ_pCAL_SUPPORTED 415 PNG_CONST PNG_pCAL; 416#endif 417#ifdef PNG_READ_pHYs_SUPPORTED 418 PNG_CONST PNG_pHYs; 419#endif 420#ifdef PNG_READ_sBIT_SUPPORTED 421 PNG_CONST PNG_sBIT; 422#endif 423#ifdef PNG_READ_sCAL_SUPPORTED 424 PNG_CONST PNG_sCAL; 425#endif 426#ifdef PNG_READ_sPLT_SUPPORTED 427 PNG_CONST PNG_sPLT; 428#endif 429#ifdef PNG_READ_sRGB_SUPPORTED 430 PNG_CONST PNG_sRGB; 431#endif 432#ifdef PNG_READ_tEXt_SUPPORTED 433 PNG_CONST PNG_tEXt; 434#endif 435#ifdef PNG_READ_tIME_SUPPORTED 436 PNG_CONST PNG_tIME; 437#endif 438#ifdef PNG_READ_tRNS_SUPPORTED 439 PNG_CONST PNG_tRNS; 440#endif 441#ifdef PNG_READ_zTXt_SUPPORTED 442 PNG_CONST PNG_zTXt; 443#endif 444#endif /* PNG_USE_LOCAL_ARRAYS */ 445 png_uint_32 length = png_read_chunk_header(png_ptr); 446 PNG_CONST png_bytep chunk_name = png_ptr->chunk_name; 447 448 /* This should be a binary subdivision search or a hash for 449 * matching the chunk name rather than a linear search. 450 */ 451 if (!png_memcmp(chunk_name, png_IDAT, 4)) 452 if (png_ptr->mode & PNG_AFTER_IDAT) 453 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT; 454 455 if (!png_memcmp(chunk_name, png_IHDR, 4)) 456 png_handle_IHDR(png_ptr, info_ptr, length); 457 else if (!png_memcmp(chunk_name, png_IEND, 4)) 458 png_handle_IEND(png_ptr, info_ptr, length); 459#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 460 else if (png_handle_as_unknown(png_ptr, chunk_name)) 461 { 462 if (!png_memcmp(chunk_name, png_IDAT, 4)) 463 png_ptr->mode |= PNG_HAVE_IDAT; 464 png_handle_unknown(png_ptr, info_ptr, length); 465 if (!png_memcmp(chunk_name, png_PLTE, 4)) 466 png_ptr->mode |= PNG_HAVE_PLTE; 467 else if (!png_memcmp(chunk_name, png_IDAT, 4)) 468 { 469 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 470 png_error(png_ptr, "Missing IHDR before IDAT"); 471 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 472 !(png_ptr->mode & PNG_HAVE_PLTE)) 473 png_error(png_ptr, "Missing PLTE before IDAT"); 474 break; 475 } 476 } 477#endif 478 else if (!png_memcmp(chunk_name, png_PLTE, 4)) 479 png_handle_PLTE(png_ptr, info_ptr, length); 480 else if (!png_memcmp(chunk_name, png_IDAT, 4)) 481 { 482 if (!(png_ptr->mode & PNG_HAVE_IHDR)) 483 png_error(png_ptr, "Missing IHDR before IDAT"); 484 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && 485 !(png_ptr->mode & PNG_HAVE_PLTE)) 486 png_error(png_ptr, "Missing PLTE before IDAT"); 487 488 png_ptr->idat_size = length; 489 png_ptr->mode |= PNG_HAVE_IDAT; 490 break; 491 } 492#ifdef PNG_READ_bKGD_SUPPORTED 493 else if (!png_memcmp(chunk_name, png_bKGD, 4)) 494 png_handle_bKGD(png_ptr, info_ptr, length); 495#endif 496#ifdef PNG_READ_cHRM_SUPPORTED 497 else if (!png_memcmp(chunk_name, png_cHRM, 4)) 498 png_handle_cHRM(png_ptr, info_ptr, length); 499#endif 500#ifdef PNG_READ_gAMA_SUPPORTED 501 else if (!png_memcmp(chunk_name, png_gAMA, 4)) 502 png_handle_gAMA(png_ptr, info_ptr, length); 503#endif 504#ifdef PNG_READ_hIST_SUPPORTED 505 else if (!png_memcmp(chunk_name, png_hIST, 4)) 506 png_handle_hIST(png_ptr, info_ptr, length); 507#endif 508#ifdef PNG_READ_oFFs_SUPPORTED 509 else if (!png_memcmp(chunk_name, png_oFFs, 4)) 510 png_handle_oFFs(png_ptr, info_ptr, length); 511#endif 512#ifdef PNG_READ_pCAL_SUPPORTED 513 else if (!png_memcmp(chunk_name, png_pCAL, 4)) 514 png_handle_pCAL(png_ptr, info_ptr, length); 515#endif 516#ifdef PNG_READ_sCAL_SUPPORTED 517 else if (!png_memcmp(chunk_name, png_sCAL, 4)) 518 png_handle_sCAL(png_ptr, info_ptr, length); 519#endif 520#ifdef PNG_READ_pHYs_SUPPORTED 521 else if (!png_memcmp(chunk_name, png_pHYs, 4)) 522 png_handle_pHYs(png_ptr, info_ptr, length); 523#endif 524#ifdef PNG_READ_sBIT_SUPPORTED 525 else if (!png_memcmp(chunk_name, png_sBIT, 4)) 526 png_handle_sBIT(png_ptr, info_ptr, length); 527#endif 528#ifdef PNG_READ_sRGB_SUPPORTED 529 else if (!png_memcmp(chunk_name, png_sRGB, 4)) 530 png_handle_sRGB(png_ptr, info_ptr, length); 531#endif 532#ifdef PNG_READ_iCCP_SUPPORTED 533 else if (!png_memcmp(chunk_name, png_iCCP, 4)) 534 png_handle_iCCP(png_ptr, info_ptr, length); 535#endif 536#ifdef PNG_READ_sPLT_SUPPORTED 537 else if (!png_memcmp(chunk_name, png_sPLT, 4)) 538 png_handle_sPLT(png_ptr, info_ptr, length); 539#endif 540#ifdef PNG_READ_tEXt_SUPPORTED 541 else if (!png_memcmp(chunk_name, png_tEXt, 4)) 542 png_handle_tEXt(png_ptr, info_ptr, length); 543#endif 544#ifdef PNG_READ_tIME_SUPPORTED 545 else if (!png_memcmp(chunk_name, png_tIME, 4)) 546 png_handle_tIME(png_ptr, info_ptr, length); 547#endif 548#ifdef PNG_READ_tRNS_SUPPORTED 549 else if (!png_memcmp(chunk_name, png_tRNS, 4)) 550 png_handle_tRNS(png_ptr, info_ptr, length); 551#endif 552#ifdef PNG_READ_zTXt_SUPPORTED 553 else if (!png_memcmp(chunk_name, png_zTXt, 4)) 554 png_handle_zTXt(png_ptr, info_ptr, length); 555#endif 556#ifdef PNG_READ_iTXt_SUPPORTED 557 else if (!png_memcmp(chunk_name, png_iTXt, 4)) 558 png_handle_iTXt(png_ptr, info_ptr, length); 559#endif 560 else 561 png_handle_unknown(png_ptr, info_ptr, length); 562 } 563} 564#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 565 566/* Optional call to update the users info_ptr structure */ 567void PNGAPI 568png_read_update_info(png_structp png_ptr, png_infop info_ptr) 569{ 570 png_debug(1, "in png_read_update_info"); 571 572 if (png_ptr == NULL) 573 return; 574#ifdef PNG_INDEX_SUPPORTED 575 if (png_ptr->index) { 576 png_read_start_row(png_ptr); 577 } 578#endif 579 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) 580 png_read_start_row(png_ptr); 581 else 582 png_warning(png_ptr, 583 "Ignoring extra png_read_update_info() call; row buffer not reallocated"); 584 585 png_read_transform_info(png_ptr, info_ptr); 586} 587 588#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 589/* Initialize palette, background, etc, after transformations 590 * are set, but before any reading takes place. This allows 591 * the user to obtain a gamma-corrected palette, for example. 592 * If the user doesn't call this, we will do it ourselves. 593 */ 594void PNGAPI 595png_start_read_image(png_structp png_ptr) 596{ 597 png_debug(1, "in png_start_read_image"); 598 599 if (png_ptr == NULL) 600 return; 601 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) 602 png_read_start_row(png_ptr); 603} 604#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 605 606#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 607void PNGAPI 608png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row) 609{ 610 PNG_CONST PNG_IDAT; 611 PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 612 0xff}; 613 PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff}; 614 int ret; 615 616 if (png_ptr == NULL) 617 return; 618 619 png_debug2(1, "in png_read_row (row %lu, pass %d)", 620 png_ptr->row_number, png_ptr->pass); 621 622 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) 623 png_read_start_row(png_ptr); 624 if (png_ptr->row_number == 0 && png_ptr->pass == 0) 625 { 626 /* Check for transforms that have been set but were defined out */ 627#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED) 628 if (png_ptr->transformations & PNG_INVERT_MONO) 629 png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined."); 630#endif 631#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED) 632 if (png_ptr->transformations & PNG_FILLER) 633 png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined."); 634#endif 635#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \ 636 !defined(PNG_READ_PACKSWAP_SUPPORTED) 637 if (png_ptr->transformations & PNG_PACKSWAP) 638 png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined."); 639#endif 640#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED) 641 if (png_ptr->transformations & PNG_PACK) 642 png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined."); 643#endif 644#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) 645 if (png_ptr->transformations & PNG_SHIFT) 646 png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined."); 647#endif 648#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED) 649 if (png_ptr->transformations & PNG_BGR) 650 png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined."); 651#endif 652#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED) 653 if (png_ptr->transformations & PNG_SWAP_BYTES) 654 png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined."); 655#endif 656 } 657 658#ifdef PNG_READ_INTERLACING_SUPPORTED 659 /* If interlaced and we do not need a new row, combine row and return */ 660 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) 661 { 662 switch (png_ptr->pass) 663 { 664 case 0: 665 if (png_ptr->row_number & 0x07) 666 { 667 if (dsp_row != NULL) 668 png_combine_row(png_ptr, dsp_row, 669 png_pass_dsp_mask[png_ptr->pass]); 670 png_read_finish_row(png_ptr); 671 return; 672 } 673 break; 674 case 1: 675 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5) 676 { 677 if (dsp_row != NULL) 678 png_combine_row(png_ptr, dsp_row, 679 png_pass_dsp_mask[png_ptr->pass]); 680 png_read_finish_row(png_ptr); 681 return; 682 } 683 break; 684 case 2: 685 if ((png_ptr->row_number & 0x07) != 4) 686 { 687 if (dsp_row != NULL && (png_ptr->row_number & 4)) 688 png_combine_row(png_ptr, dsp_row, 689 png_pass_dsp_mask[png_ptr->pass]); 690 png_read_finish_row(png_ptr); 691 return; 692 } 693 break; 694 case 3: 695 if ((png_ptr->row_number & 3) || png_ptr->width < 3) 696 { 697 if (dsp_row != NULL) 698 png_combine_row(png_ptr, dsp_row, 699 png_pass_dsp_mask[png_ptr->pass]); 700 png_read_finish_row(png_ptr); 701 return; 702 } 703 break; 704 case 4: 705 if ((png_ptr->row_number & 3) != 2) 706 { 707 if (dsp_row != NULL && (png_ptr->row_number & 2)) 708 png_combine_row(png_ptr, dsp_row, 709 png_pass_dsp_mask[png_ptr->pass]); 710 png_read_finish_row(png_ptr); 711 return; 712 } 713 break; 714 case 5: 715 if ((png_ptr->row_number & 1) || png_ptr->width < 2) 716 { 717 if (dsp_row != NULL) 718 png_combine_row(png_ptr, dsp_row, 719 png_pass_dsp_mask[png_ptr->pass]); 720 png_read_finish_row(png_ptr); 721 return; 722 } 723 break; 724 case 6: 725 if (!(png_ptr->row_number & 1)) 726 { 727 png_read_finish_row(png_ptr); 728 return; 729 } 730 break; 731 } 732 } 733#endif 734 735 if (!(png_ptr->mode & PNG_HAVE_IDAT)) 736 png_error(png_ptr, "Invalid attempt to read row data"); 737 738 png_ptr->zstream.next_out = png_ptr->row_buf; 739 png_ptr->zstream.avail_out = 740 (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth, 741 png_ptr->iwidth) + 1); 742 do 743 { 744 if (!(png_ptr->zstream.avail_in)) 745 { 746 while (!png_ptr->idat_size) 747 { 748#ifdef PNG_INDEX_SUPPORTED 749 if (png_ptr->index) { 750 png_opt_crc_finish(png_ptr, 0, 0); 751 png_ptr->index->stream_idat_position = png_ptr->total_data_read; 752 } else 753#endif 754 png_crc_finish(png_ptr, 0); 755 756 757 png_ptr->idat_size = png_read_chunk_header(png_ptr); 758 if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4)) 759 png_error(png_ptr, "Not enough image data"); 760 } 761 png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size; 762 png_ptr->zstream.next_in = png_ptr->zbuf; 763 if (png_ptr->zbuf_size > png_ptr->idat_size) 764 png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size; 765 png_crc_read(png_ptr, png_ptr->zbuf, 766 (png_size_t)png_ptr->zstream.avail_in); 767 png_ptr->idat_size -= png_ptr->zstream.avail_in; 768 } 769 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH); 770 if (ret == Z_STREAM_END) 771 { 772 if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in || 773 png_ptr->idat_size) 774 png_error(png_ptr, "Extra compressed data"); 775 png_ptr->mode |= PNG_AFTER_IDAT; 776 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; 777 break; 778 } 779 if (ret != Z_OK) { 780#ifdef PNG_INDEX_SUPPORTED 781 if (png_ptr->index) { 782 if (png_ptr->row_number != png_ptr->height - 1) { 783 png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg : 784 "Decompression error"); 785 } 786 } else 787#endif 788 png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg : 789 "Decompression error"); 790 } 791 } while (png_ptr->zstream.avail_out); 792 793 png_ptr->row_info.color_type = png_ptr->color_type; 794 png_ptr->row_info.width = png_ptr->iwidth; 795 png_ptr->row_info.channels = png_ptr->channels; 796 png_ptr->row_info.bit_depth = png_ptr->bit_depth; 797 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth; 798 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth, 799 png_ptr->row_info.width); 800 801 if (png_ptr->row_buf[0]) 802 png_read_filter_row(png_ptr, &(png_ptr->row_info), 803 png_ptr->row_buf + 1, png_ptr->prev_row + 1, 804 (int)(png_ptr->row_buf[0])); 805 806 png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf, 807 png_ptr->rowbytes + 1); 808 809#ifdef PNG_MNG_FEATURES_SUPPORTED 810 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && 811 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING)) 812 { 813 /* Intrapixel differencing */ 814 png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1); 815 } 816#endif 817 818 819 if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA)) 820 png_do_read_transformations(png_ptr); 821 822#ifdef PNG_READ_INTERLACING_SUPPORTED 823 /* Blow up interlaced rows to full size */ 824 if (png_ptr->interlaced && 825 (png_ptr->transformations & PNG_INTERLACE)) 826 { 827 if (png_ptr->pass < 6) 828 /* Old interface (pre-1.0.9): 829 * png_do_read_interlace(&(png_ptr->row_info), 830 * png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations); 831 */ 832 png_do_read_interlace(png_ptr); 833 834 if (dsp_row != NULL) 835 png_combine_row(png_ptr, dsp_row, 836 png_pass_dsp_mask[png_ptr->pass]); 837 if (row != NULL) 838 png_combine_row(png_ptr, row, 839 png_pass_mask[png_ptr->pass]); 840 } 841 else 842#endif 843 { 844 if (row != NULL) 845 png_combine_row(png_ptr, row, 0xff); 846 if (dsp_row != NULL) 847 png_combine_row(png_ptr, dsp_row, 0xff); 848 } 849 png_read_finish_row(png_ptr); 850 851 if (png_ptr->read_row_fn != NULL) 852 (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass); 853} 854#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 855 856#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 857/* Read one or more rows of image data. If the image is interlaced, 858 * and png_set_interlace_handling() has been called, the rows need to 859 * contain the contents of the rows from the previous pass. If the 860 * image has alpha or transparency, and png_handle_alpha()[*] has been 861 * called, the rows contents must be initialized to the contents of the 862 * screen. 863 * 864 * "row" holds the actual image, and pixels are placed in it 865 * as they arrive. If the image is displayed after each pass, it will 866 * appear to "sparkle" in. "display_row" can be used to display a 867 * "chunky" progressive image, with finer detail added as it becomes 868 * available. If you do not want this "chunky" display, you may pass 869 * NULL for display_row. If you do not want the sparkle display, and 870 * you have not called png_handle_alpha(), you may pass NULL for rows. 871 * If you have called png_handle_alpha(), and the image has either an 872 * alpha channel or a transparency chunk, you must provide a buffer for 873 * rows. In this case, you do not have to provide a display_row buffer 874 * also, but you may. If the image is not interlaced, or if you have 875 * not called png_set_interlace_handling(), the display_row buffer will 876 * be ignored, so pass NULL to it. 877 * 878 * [*] png_handle_alpha() does not exist yet, as of this version of libpng 879 */ 880 881void PNGAPI 882png_read_rows(png_structp png_ptr, png_bytepp row, 883 png_bytepp display_row, png_uint_32 num_rows) 884{ 885 png_uint_32 i; 886 png_bytepp rp; 887 png_bytepp dp; 888 889 png_debug(1, "in png_read_rows"); 890 891 if (png_ptr == NULL) 892 return; 893 rp = row; 894 dp = display_row; 895 if (rp != NULL && dp != NULL) 896 for (i = 0; i < num_rows; i++) 897 { 898 png_bytep rptr = *rp++; 899 png_bytep dptr = *dp++; 900 901 png_read_row(png_ptr, rptr, dptr); 902 } 903 else if (rp != NULL) 904 for (i = 0; i < num_rows; i++) 905 { 906 png_bytep rptr = *rp; 907 png_read_row(png_ptr, rptr, png_bytep_NULL); 908 rp++; 909 } 910 else if (dp != NULL) 911 for (i = 0; i < num_rows; i++) 912 { 913 png_bytep dptr = *dp; 914 png_read_row(png_ptr, png_bytep_NULL, dptr); 915 dp++; 916 } 917} 918#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 919 920#ifdef PNG_INDEX_SUPPORTED 921#define IDAT_HEADER_SIZE 8 922 923/* Set the png read position to a new position based on idat_position and 924 * offset. 925 */ 926void 927png_set_read_offset(png_structp png_ptr, 928 png_uint_32 idat_position, png_uint_32 bytes_left) 929{ 930 png_seek_data(png_ptr, idat_position); 931 png_ptr->idat_size = png_read_chunk_header(png_ptr); 932 933 // We need to add back IDAT_HEADER_SIZE because in zlib's perspective, 934 // IDAT_HEADER in PNG is already stripped out. 935 png_seek_data(png_ptr, idat_position + IDAT_HEADER_SIZE + png_ptr->idat_size - bytes_left); 936 png_ptr->idat_size = bytes_left; 937} 938 939/* Configure png decoder to decode the pass starting from *row. 940 * The requested row may be adjusted to align with an indexing row. 941 * The actual row for the decoder to start its decoding will be returned in 942 * *row. 943 */ 944void PNGAPI 945png_configure_decoder(png_structp png_ptr, int *row, int pass) 946{ 947 png_indexp index = png_ptr->index; 948 int n = *row / index->step[pass]; 949 png_line_indexp line_index = index->pass_line_index[pass][n]; 950 951 // Adjust row to an indexing row. 952 *row = n * index->step[pass]; 953 png_ptr->row_number = *row; 954 955#ifdef PNG_READ_INTERLACING_SUPPORTED 956 if (png_ptr->interlaced) 957 png_set_interlaced_pass(png_ptr, pass); 958#endif 959 960 long row_byte_length = 961 PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1; 962 963 inflateEnd(&png_ptr->zstream); 964 inflateCopy(&png_ptr->zstream, line_index->z_state); 965 966 // Set the png read position to line_index. 967 png_set_read_offset(png_ptr, line_index->stream_idat_position, 968 line_index->bytes_left_in_idat); 969 png_memcpy_check(png_ptr, 970 png_ptr->prev_row, line_index->prev_row, row_byte_length); 971 png_ptr->zstream.avail_in = 0; 972} 973 974/* Build the line index and store the index in png_ptr->index. 975 */ 976void PNGAPI 977png_build_index(png_structp png_ptr) 978{ 979 // number of rows in a 8x8 block for each interlaced pass. 980 int number_rows_in_pass[7] = {1, 1, 1, 2, 2, 4, 4}; 981 982 int ret; 983 png_uint_32 i, j; 984 png_bytep rp; 985 int p, pass_number = 1; 986 987#ifdef PNG_READ_INTERLACING_SUPPORTED 988 pass_number = png_set_interlace_handling(png_ptr); 989#endif 990 991 if (png_ptr == NULL) 992 return; 993 994 png_read_start_row(png_ptr); 995 996#ifdef PNG_READ_INTERLACING_SUPPORTED 997 if (!png_ptr->interlaced) 998#endif 999 { 1000 number_rows_in_pass[0] = 8; 1001 } 1002 1003 rp = png_malloc(png_ptr, png_ptr->rowbytes); 1004 1005 png_indexp index = png_malloc(png_ptr, sizeof(png_index)); 1006 png_ptr->index = index; 1007 1008 index->stream_idat_position = png_ptr->total_data_read - IDAT_HEADER_SIZE; 1009 1010 // Set the default size of index in each pass to 0, 1011 // so that we can free index correctly in png_destroy_read_struct. 1012 for (p = 0; p < 7; p++) 1013 index->size[p] = 0; 1014 1015 for (p = 0; p < pass_number; p++) 1016 { 1017 // We adjust the index step in each pass to make sure each pass 1018 // has roughly the same size of index. 1019 // This way, we won't consume to much memory in recording index. 1020 index->step[p] = INDEX_SAMPLE_SIZE * (8 / number_rows_in_pass[p]); 1021 index->size[p] = 1022 (png_ptr->height + index->step[p] - 1) / index->step[p]; 1023 index->pass_line_index[p] = 1024 png_malloc(png_ptr, index->size[p] * sizeof(png_line_indexp)); 1025 1026 // Get the row_byte_length seen by the filter. This value may be 1027 // different from the row_byte_length of a bitmap in the case of 1028 // color palette mode. 1029 int row_byte_length = 1030 PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1; 1031 1032 // Now, we record index for each indexing row. 1033 for (i = 0; i < index->size[p]; i++) 1034 { 1035 png_line_indexp line_index = png_malloc(png_ptr, sizeof(png_line_index)); 1036 index->pass_line_index[p][i] = line_index; 1037 1038 line_index->z_state = png_malloc(png_ptr, sizeof(z_stream)); 1039 inflateCopy(line_index->z_state, &png_ptr->zstream); 1040 line_index->prev_row = png_malloc(png_ptr, row_byte_length); 1041 png_memcpy_check(png_ptr, 1042 line_index->prev_row, png_ptr->prev_row, row_byte_length); 1043 line_index->stream_idat_position = index->stream_idat_position; 1044 line_index->bytes_left_in_idat = png_ptr->idat_size + png_ptr->zstream.avail_in; 1045 1046 // Skip the "step" number of rows to the next indexing row. 1047 for (j = 0; j < index->step[p] && 1048 i * index->step[p] + j < png_ptr->height; j++) 1049 { 1050 png_read_row(png_ptr, rp, png_bytep_NULL); 1051 } 1052 } 1053 } 1054 png_free(png_ptr, rp); 1055} 1056#endif 1057 1058#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1059/* Read the entire image. If the image has an alpha channel or a tRNS 1060 * chunk, and you have called png_handle_alpha()[*], you will need to 1061 * initialize the image to the current image that PNG will be overlaying. 1062 * We set the num_rows again here, in case it was incorrectly set in 1063 * png_read_start_row() by a call to png_read_update_info() or 1064 * png_start_read_image() if png_set_interlace_handling() wasn't called 1065 * prior to either of these functions like it should have been. You can 1066 * only call this function once. If you desire to have an image for 1067 * each pass of a interlaced image, use png_read_rows() instead. 1068 * 1069 * [*] png_handle_alpha() does not exist yet, as of this version of libpng 1070 */ 1071void PNGAPI 1072png_read_image(png_structp png_ptr, png_bytepp image) 1073{ 1074 png_uint_32 i, image_height; 1075 int pass, j; 1076 png_bytepp rp; 1077 1078 png_debug(1, "in png_read_image"); 1079 1080 if (png_ptr == NULL) 1081 return; 1082 1083#ifdef PNG_READ_INTERLACING_SUPPORTED 1084 pass = png_set_interlace_handling(png_ptr); 1085#else 1086 if (png_ptr->interlaced) 1087 png_error(png_ptr, 1088 "Cannot read interlaced image -- interlace handler disabled."); 1089 pass = 1; 1090#endif 1091 1092 1093 image_height=png_ptr->height; 1094 png_ptr->num_rows = image_height; /* Make sure this is set correctly */ 1095 1096 for (j = 0; j < pass; j++) 1097 { 1098 rp = image; 1099 for (i = 0; i < image_height; i++) 1100 { 1101 png_read_row(png_ptr, *rp, png_bytep_NULL); 1102 rp++; 1103 } 1104 } 1105} 1106#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 1107 1108#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1109/* Read the end of the PNG file. Will not read past the end of the 1110 * file, will verify the end is accurate, and will read any comments 1111 * or time information at the end of the file, if info is not NULL. 1112 */ 1113void PNGAPI 1114png_read_end(png_structp png_ptr, png_infop info_ptr) 1115{ 1116 png_debug(1, "in png_read_end"); 1117 1118 if (png_ptr == NULL) 1119 return; 1120 png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */ 1121 1122 do 1123 { 1124#ifdef PNG_USE_LOCAL_ARRAYS 1125 PNG_CONST PNG_IHDR; 1126 PNG_CONST PNG_IDAT; 1127 PNG_CONST PNG_IEND; 1128 PNG_CONST PNG_PLTE; 1129#ifdef PNG_READ_bKGD_SUPPORTED 1130 PNG_CONST PNG_bKGD; 1131#endif 1132#ifdef PNG_READ_cHRM_SUPPORTED 1133 PNG_CONST PNG_cHRM; 1134#endif 1135#ifdef PNG_READ_gAMA_SUPPORTED 1136 PNG_CONST PNG_gAMA; 1137#endif 1138#ifdef PNG_READ_hIST_SUPPORTED 1139 PNG_CONST PNG_hIST; 1140#endif 1141#ifdef PNG_READ_iCCP_SUPPORTED 1142 PNG_CONST PNG_iCCP; 1143#endif 1144#ifdef PNG_READ_iTXt_SUPPORTED 1145 PNG_CONST PNG_iTXt; 1146#endif 1147#ifdef PNG_READ_oFFs_SUPPORTED 1148 PNG_CONST PNG_oFFs; 1149#endif 1150#ifdef PNG_READ_pCAL_SUPPORTED 1151 PNG_CONST PNG_pCAL; 1152#endif 1153#ifdef PNG_READ_pHYs_SUPPORTED 1154 PNG_CONST PNG_pHYs; 1155#endif 1156#ifdef PNG_READ_sBIT_SUPPORTED 1157 PNG_CONST PNG_sBIT; 1158#endif 1159#ifdef PNG_READ_sCAL_SUPPORTED 1160 PNG_CONST PNG_sCAL; 1161#endif 1162#ifdef PNG_READ_sPLT_SUPPORTED 1163 PNG_CONST PNG_sPLT; 1164#endif 1165#ifdef PNG_READ_sRGB_SUPPORTED 1166 PNG_CONST PNG_sRGB; 1167#endif 1168#ifdef PNG_READ_tEXt_SUPPORTED 1169 PNG_CONST PNG_tEXt; 1170#endif 1171#ifdef PNG_READ_tIME_SUPPORTED 1172 PNG_CONST PNG_tIME; 1173#endif 1174#ifdef PNG_READ_tRNS_SUPPORTED 1175 PNG_CONST PNG_tRNS; 1176#endif 1177#ifdef PNG_READ_zTXt_SUPPORTED 1178 PNG_CONST PNG_zTXt; 1179#endif 1180#endif /* PNG_USE_LOCAL_ARRAYS */ 1181 png_uint_32 length = png_read_chunk_header(png_ptr); 1182 PNG_CONST png_bytep chunk_name = png_ptr->chunk_name; 1183 1184 if (!png_memcmp(chunk_name, png_IHDR, 4)) 1185 png_handle_IHDR(png_ptr, info_ptr, length); 1186 else if (!png_memcmp(chunk_name, png_IEND, 4)) 1187 png_handle_IEND(png_ptr, info_ptr, length); 1188#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 1189 else if (png_handle_as_unknown(png_ptr, chunk_name)) 1190 { 1191 if (!png_memcmp(chunk_name, png_IDAT, 4)) 1192 { 1193 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) 1194 png_error(png_ptr, "Too many IDAT's found"); 1195 } 1196 png_handle_unknown(png_ptr, info_ptr, length); 1197 if (!png_memcmp(chunk_name, png_PLTE, 4)) 1198 png_ptr->mode |= PNG_HAVE_PLTE; 1199 } 1200#endif 1201 else if (!png_memcmp(chunk_name, png_IDAT, 4)) 1202 { 1203 /* Zero length IDATs are legal after the last IDAT has been 1204 * read, but not after other chunks have been read. 1205 */ 1206 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) 1207 png_error(png_ptr, "Too many IDAT's found"); 1208 png_crc_finish(png_ptr, length); 1209 } 1210 else if (!png_memcmp(chunk_name, png_PLTE, 4)) 1211 png_handle_PLTE(png_ptr, info_ptr, length); 1212#ifdef PNG_READ_bKGD_SUPPORTED 1213 else if (!png_memcmp(chunk_name, png_bKGD, 4)) 1214 png_handle_bKGD(png_ptr, info_ptr, length); 1215#endif 1216#ifdef PNG_READ_cHRM_SUPPORTED 1217 else if (!png_memcmp(chunk_name, png_cHRM, 4)) 1218 png_handle_cHRM(png_ptr, info_ptr, length); 1219#endif 1220#ifdef PNG_READ_gAMA_SUPPORTED 1221 else if (!png_memcmp(chunk_name, png_gAMA, 4)) 1222 png_handle_gAMA(png_ptr, info_ptr, length); 1223#endif 1224#ifdef PNG_READ_hIST_SUPPORTED 1225 else if (!png_memcmp(chunk_name, png_hIST, 4)) 1226 png_handle_hIST(png_ptr, info_ptr, length); 1227#endif 1228#ifdef PNG_READ_oFFs_SUPPORTED 1229 else if (!png_memcmp(chunk_name, png_oFFs, 4)) 1230 png_handle_oFFs(png_ptr, info_ptr, length); 1231#endif 1232#ifdef PNG_READ_pCAL_SUPPORTED 1233 else if (!png_memcmp(chunk_name, png_pCAL, 4)) 1234 png_handle_pCAL(png_ptr, info_ptr, length); 1235#endif 1236#ifdef PNG_READ_sCAL_SUPPORTED 1237 else if (!png_memcmp(chunk_name, png_sCAL, 4)) 1238 png_handle_sCAL(png_ptr, info_ptr, length); 1239#endif 1240#ifdef PNG_READ_pHYs_SUPPORTED 1241 else if (!png_memcmp(chunk_name, png_pHYs, 4)) 1242 png_handle_pHYs(png_ptr, info_ptr, length); 1243#endif 1244#ifdef PNG_READ_sBIT_SUPPORTED 1245 else if (!png_memcmp(chunk_name, png_sBIT, 4)) 1246 png_handle_sBIT(png_ptr, info_ptr, length); 1247#endif 1248#ifdef PNG_READ_sRGB_SUPPORTED 1249 else if (!png_memcmp(chunk_name, png_sRGB, 4)) 1250 png_handle_sRGB(png_ptr, info_ptr, length); 1251#endif 1252#ifdef PNG_READ_iCCP_SUPPORTED 1253 else if (!png_memcmp(chunk_name, png_iCCP, 4)) 1254 png_handle_iCCP(png_ptr, info_ptr, length); 1255#endif 1256#ifdef PNG_READ_sPLT_SUPPORTED 1257 else if (!png_memcmp(chunk_name, png_sPLT, 4)) 1258 png_handle_sPLT(png_ptr, info_ptr, length); 1259#endif 1260#ifdef PNG_READ_tEXt_SUPPORTED 1261 else if (!png_memcmp(chunk_name, png_tEXt, 4)) 1262 png_handle_tEXt(png_ptr, info_ptr, length); 1263#endif 1264#ifdef PNG_READ_tIME_SUPPORTED 1265 else if (!png_memcmp(chunk_name, png_tIME, 4)) 1266 png_handle_tIME(png_ptr, info_ptr, length); 1267#endif 1268#ifdef PNG_READ_tRNS_SUPPORTED 1269 else if (!png_memcmp(chunk_name, png_tRNS, 4)) 1270 png_handle_tRNS(png_ptr, info_ptr, length); 1271#endif 1272#ifdef PNG_READ_zTXt_SUPPORTED 1273 else if (!png_memcmp(chunk_name, png_zTXt, 4)) 1274 png_handle_zTXt(png_ptr, info_ptr, length); 1275#endif 1276#ifdef PNG_READ_iTXt_SUPPORTED 1277 else if (!png_memcmp(chunk_name, png_iTXt, 4)) 1278 png_handle_iTXt(png_ptr, info_ptr, length); 1279#endif 1280 else 1281 png_handle_unknown(png_ptr, info_ptr, length); 1282 } while (!(png_ptr->mode & PNG_HAVE_IEND)); 1283} 1284#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 1285 1286/* Free all memory used by the read */ 1287void PNGAPI 1288png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr, 1289 png_infopp end_info_ptr_ptr) 1290{ 1291 png_structp png_ptr = NULL; 1292 png_infop info_ptr = NULL, end_info_ptr = NULL; 1293#ifdef PNG_USER_MEM_SUPPORTED 1294 png_free_ptr free_fn = NULL; 1295 png_voidp mem_ptr = NULL; 1296#endif 1297 1298 png_debug(1, "in png_destroy_read_struct"); 1299 1300 if (png_ptr_ptr != NULL) 1301 png_ptr = *png_ptr_ptr; 1302 if (png_ptr == NULL) 1303 return; 1304 1305#ifdef PNG_USER_MEM_SUPPORTED 1306 free_fn = png_ptr->free_fn; 1307 mem_ptr = png_ptr->mem_ptr; 1308#endif 1309 1310 if (info_ptr_ptr != NULL) 1311 info_ptr = *info_ptr_ptr; 1312 1313 if (end_info_ptr_ptr != NULL) 1314 end_info_ptr = *end_info_ptr_ptr; 1315 1316 png_read_destroy(png_ptr, info_ptr, end_info_ptr); 1317 1318 if (info_ptr != NULL) 1319 { 1320#ifdef PNG_TEXT_SUPPORTED 1321 png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1); 1322#endif 1323 1324#ifdef PNG_USER_MEM_SUPPORTED 1325 png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn, 1326 (png_voidp)mem_ptr); 1327#else 1328 png_destroy_struct((png_voidp)info_ptr); 1329#endif 1330 *info_ptr_ptr = NULL; 1331 } 1332 1333 if (end_info_ptr != NULL) 1334 { 1335#ifdef PNG_READ_TEXT_SUPPORTED 1336 png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1); 1337#endif 1338#ifdef PNG_USER_MEM_SUPPORTED 1339 png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn, 1340 (png_voidp)mem_ptr); 1341#else 1342 png_destroy_struct((png_voidp)end_info_ptr); 1343#endif 1344 *end_info_ptr_ptr = NULL; 1345 } 1346 1347 if (png_ptr != NULL) 1348 { 1349#ifdef PNG_INDEX_SUPPORTED 1350 if (png_ptr->index) { 1351 unsigned int i, p; 1352 png_indexp index = png_ptr->index; 1353 for (p = 0; p < 7; p++) { 1354 for (i = 0; i < index->size[p]; i++) { 1355 inflateEnd(index->pass_line_index[p][i]->z_state); 1356 png_free(png_ptr, index->pass_line_index[p][i]->z_state); 1357 png_free(png_ptr, index->pass_line_index[p][i]->prev_row); 1358 png_free(png_ptr, index->pass_line_index[p][i]); 1359 } 1360 if (index->size[p] != 0) { 1361 png_free(png_ptr, index->pass_line_index[p]); 1362 } 1363 } 1364 png_free(png_ptr, index); 1365 } 1366#endif 1367#ifdef PNG_USER_MEM_SUPPORTED 1368 png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn, 1369 (png_voidp)mem_ptr); 1370#else 1371 png_destroy_struct((png_voidp)png_ptr); 1372#endif 1373 *png_ptr_ptr = NULL; 1374 } 1375} 1376 1377/* Free all memory used by the read (old method) */ 1378void /* PRIVATE */ 1379png_read_destroy(png_structp png_ptr, png_infop info_ptr, 1380 png_infop end_info_ptr) 1381{ 1382#ifdef PNG_SETJMP_SUPPORTED 1383 jmp_buf tmp_jmp; 1384#endif 1385 png_error_ptr error_fn; 1386 png_error_ptr warning_fn; 1387 png_voidp error_ptr; 1388#ifdef PNG_USER_MEM_SUPPORTED 1389 png_free_ptr free_fn; 1390#endif 1391 1392 png_debug(1, "in png_read_destroy"); 1393 1394 if (info_ptr != NULL) 1395 png_info_destroy(png_ptr, info_ptr); 1396 1397 if (end_info_ptr != NULL) 1398 png_info_destroy(png_ptr, end_info_ptr); 1399 1400 png_free(png_ptr, png_ptr->zbuf); 1401 png_free(png_ptr, png_ptr->big_row_buf); 1402 png_free(png_ptr, png_ptr->prev_row); 1403 png_free(png_ptr, png_ptr->chunkdata); 1404#ifdef PNG_READ_DITHER_SUPPORTED 1405 png_free(png_ptr, png_ptr->palette_lookup); 1406 png_free(png_ptr, png_ptr->dither_index); 1407#endif 1408#ifdef PNG_READ_GAMMA_SUPPORTED 1409 png_free(png_ptr, png_ptr->gamma_table); 1410#endif 1411#ifdef PNG_READ_BACKGROUND_SUPPORTED 1412 png_free(png_ptr, png_ptr->gamma_from_1); 1413 png_free(png_ptr, png_ptr->gamma_to_1); 1414#endif 1415#ifdef PNG_FREE_ME_SUPPORTED 1416 if (png_ptr->free_me & PNG_FREE_PLTE) 1417 png_zfree(png_ptr, png_ptr->palette); 1418 png_ptr->free_me &= ~PNG_FREE_PLTE; 1419#else 1420 if (png_ptr->flags & PNG_FLAG_FREE_PLTE) 1421 png_zfree(png_ptr, png_ptr->palette); 1422 png_ptr->flags &= ~PNG_FLAG_FREE_PLTE; 1423#endif 1424#if defined(PNG_tRNS_SUPPORTED) || \ 1425 defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) 1426#ifdef PNG_FREE_ME_SUPPORTED 1427 if (png_ptr->free_me & PNG_FREE_TRNS) 1428 png_free(png_ptr, png_ptr->trans); 1429 png_ptr->free_me &= ~PNG_FREE_TRNS; 1430#else 1431 if (png_ptr->flags & PNG_FLAG_FREE_TRNS) 1432 png_free(png_ptr, png_ptr->trans); 1433 png_ptr->flags &= ~PNG_FLAG_FREE_TRNS; 1434#endif 1435#endif 1436#ifdef PNG_READ_hIST_SUPPORTED 1437#ifdef PNG_FREE_ME_SUPPORTED 1438 if (png_ptr->free_me & PNG_FREE_HIST) 1439 png_free(png_ptr, png_ptr->hist); 1440 png_ptr->free_me &= ~PNG_FREE_HIST; 1441#else 1442 if (png_ptr->flags & PNG_FLAG_FREE_HIST) 1443 png_free(png_ptr, png_ptr->hist); 1444 png_ptr->flags &= ~PNG_FLAG_FREE_HIST; 1445#endif 1446#endif 1447#ifdef PNG_READ_GAMMA_SUPPORTED 1448 if (png_ptr->gamma_16_table != NULL) 1449 { 1450 int i; 1451 int istop = (1 << (8 - png_ptr->gamma_shift)); 1452 for (i = 0; i < istop; i++) 1453 { 1454 png_free(png_ptr, png_ptr->gamma_16_table[i]); 1455 } 1456 png_free(png_ptr, png_ptr->gamma_16_table); 1457 } 1458#ifdef PNG_READ_BACKGROUND_SUPPORTED 1459 if (png_ptr->gamma_16_from_1 != NULL) 1460 { 1461 int i; 1462 int istop = (1 << (8 - png_ptr->gamma_shift)); 1463 for (i = 0; i < istop; i++) 1464 { 1465 png_free(png_ptr, png_ptr->gamma_16_from_1[i]); 1466 } 1467 png_free(png_ptr, png_ptr->gamma_16_from_1); 1468 } 1469 if (png_ptr->gamma_16_to_1 != NULL) 1470 { 1471 int i; 1472 int istop = (1 << (8 - png_ptr->gamma_shift)); 1473 for (i = 0; i < istop; i++) 1474 { 1475 png_free(png_ptr, png_ptr->gamma_16_to_1[i]); 1476 } 1477 png_free(png_ptr, png_ptr->gamma_16_to_1); 1478 } 1479#endif 1480#endif 1481#ifdef PNG_TIME_RFC1123_SUPPORTED 1482 png_free(png_ptr, png_ptr->time_buffer); 1483#endif 1484 1485 inflateEnd(&png_ptr->zstream); 1486#ifdef PNG_PROGRESSIVE_READ_SUPPORTED 1487 png_free(png_ptr, png_ptr->save_buffer); 1488#endif 1489 1490#ifdef PNG_PROGRESSIVE_READ_SUPPORTED 1491#ifdef PNG_TEXT_SUPPORTED 1492 png_free(png_ptr, png_ptr->current_text); 1493#endif /* PNG_TEXT_SUPPORTED */ 1494#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ 1495 1496 /* Save the important info out of the png_struct, in case it is 1497 * being used again. 1498 */ 1499#ifdef PNG_SETJMP_SUPPORTED 1500 png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf)); 1501#endif 1502 1503 error_fn = png_ptr->error_fn; 1504 warning_fn = png_ptr->warning_fn; 1505 error_ptr = png_ptr->error_ptr; 1506#ifdef PNG_USER_MEM_SUPPORTED 1507 free_fn = png_ptr->free_fn; 1508#endif 1509 1510 png_memset(png_ptr, 0, png_sizeof(png_struct)); 1511 1512 png_ptr->error_fn = error_fn; 1513 png_ptr->warning_fn = warning_fn; 1514 png_ptr->error_ptr = error_ptr; 1515#ifdef PNG_USER_MEM_SUPPORTED 1516 png_ptr->free_fn = free_fn; 1517#endif 1518 1519#ifdef PNG_SETJMP_SUPPORTED 1520 png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf)); 1521#endif 1522 1523} 1524 1525void PNGAPI 1526png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn) 1527{ 1528 if (png_ptr == NULL) 1529 return; 1530 png_ptr->read_row_fn = read_row_fn; 1531} 1532 1533 1534#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1535#ifdef PNG_INFO_IMAGE_SUPPORTED 1536void PNGAPI 1537png_read_png(png_structp png_ptr, png_infop info_ptr, 1538 int transforms, 1539 voidp params) 1540{ 1541 int row; 1542 1543 if (png_ptr == NULL) 1544 return; 1545#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED 1546 /* Invert the alpha channel from opacity to transparency 1547 */ 1548 if (transforms & PNG_TRANSFORM_INVERT_ALPHA) 1549 png_set_invert_alpha(png_ptr); 1550#endif 1551 1552 /* png_read_info() gives us all of the information from the 1553 * PNG file before the first IDAT (image data chunk). 1554 */ 1555 png_read_info(png_ptr, info_ptr); 1556 if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep)) 1557 png_error(png_ptr, "Image is too high to process with png_read_png()"); 1558 1559 /* -------------- image transformations start here ------------------- */ 1560 1561#ifdef PNG_READ_16_TO_8_SUPPORTED 1562 /* Tell libpng to strip 16 bit/color files down to 8 bits per color. 1563 */ 1564 if (transforms & PNG_TRANSFORM_STRIP_16) 1565 png_set_strip_16(png_ptr); 1566#endif 1567 1568#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED 1569 /* Strip alpha bytes from the input data without combining with 1570 * the background (not recommended). 1571 */ 1572 if (transforms & PNG_TRANSFORM_STRIP_ALPHA) 1573 png_set_strip_alpha(png_ptr); 1574#endif 1575 1576#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED) 1577 /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single 1578 * byte into separate bytes (useful for paletted and grayscale images). 1579 */ 1580 if (transforms & PNG_TRANSFORM_PACKING) 1581 png_set_packing(png_ptr); 1582#endif 1583 1584#ifdef PNG_READ_PACKSWAP_SUPPORTED 1585 /* Change the order of packed pixels to least significant bit first 1586 * (not useful if you are using png_set_packing). 1587 */ 1588 if (transforms & PNG_TRANSFORM_PACKSWAP) 1589 png_set_packswap(png_ptr); 1590#endif 1591 1592#ifdef PNG_READ_EXPAND_SUPPORTED 1593 /* Expand paletted colors into true RGB triplets 1594 * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel 1595 * Expand paletted or RGB images with transparency to full alpha 1596 * channels so the data will be available as RGBA quartets. 1597 */ 1598 if (transforms & PNG_TRANSFORM_EXPAND) 1599 if ((png_ptr->bit_depth < 8) || 1600 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) || 1601 (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))) 1602 png_set_expand(png_ptr); 1603#endif 1604 1605 /* We don't handle background color or gamma transformation or dithering. 1606 */ 1607 1608#ifdef PNG_READ_INVERT_SUPPORTED 1609 /* Invert monochrome files to have 0 as white and 1 as black 1610 */ 1611 if (transforms & PNG_TRANSFORM_INVERT_MONO) 1612 png_set_invert_mono(png_ptr); 1613#endif 1614 1615#ifdef PNG_READ_SHIFT_SUPPORTED 1616 /* If you want to shift the pixel values from the range [0,255] or 1617 * [0,65535] to the original [0,7] or [0,31], or whatever range the 1618 * colors were originally in: 1619 */ 1620 if ((transforms & PNG_TRANSFORM_SHIFT) 1621 && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT)) 1622 { 1623 png_color_8p sig_bit; 1624 1625 png_get_sBIT(png_ptr, info_ptr, &sig_bit); 1626 png_set_shift(png_ptr, sig_bit); 1627 } 1628#endif 1629 1630#ifdef PNG_READ_BGR_SUPPORTED 1631 /* Flip the RGB pixels to BGR (or RGBA to BGRA) 1632 */ 1633 if (transforms & PNG_TRANSFORM_BGR) 1634 png_set_bgr(png_ptr); 1635#endif 1636 1637#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED 1638 /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) 1639 */ 1640 if (transforms & PNG_TRANSFORM_SWAP_ALPHA) 1641 png_set_swap_alpha(png_ptr); 1642#endif 1643 1644#ifdef PNG_READ_SWAP_SUPPORTED 1645 /* Swap bytes of 16 bit files to least significant byte first 1646 */ 1647 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN) 1648 png_set_swap(png_ptr); 1649#endif 1650 1651/* Added at libpng-1.2.41 */ 1652#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED 1653 /* Invert the alpha channel from opacity to transparency 1654 */ 1655 if (transforms & PNG_TRANSFORM_INVERT_ALPHA) 1656 png_set_invert_alpha(png_ptr); 1657#endif 1658 1659/* Added at libpng-1.2.41 */ 1660#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 1661 /* Expand grayscale image to RGB 1662 */ 1663 if (transforms & PNG_TRANSFORM_GRAY_TO_RGB) 1664 png_set_gray_to_rgb(png_ptr); 1665#endif 1666 1667 /* We don't handle adding filler bytes */ 1668 1669 /* Optional call to gamma correct and add the background to the palette 1670 * and update info structure. REQUIRED if you are expecting libpng to 1671 * update the palette for you (i.e., you selected such a transform above). 1672 */ 1673 png_read_update_info(png_ptr, info_ptr); 1674 1675 /* -------------- image transformations end here ------------------- */ 1676 1677#ifdef PNG_FREE_ME_SUPPORTED 1678 png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0); 1679#endif 1680 if (info_ptr->row_pointers == NULL) 1681 { 1682 info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr, 1683 info_ptr->height * png_sizeof(png_bytep)); 1684 png_memset(info_ptr->row_pointers, 0, info_ptr->height 1685 * png_sizeof(png_bytep)); 1686 1687#ifdef PNG_FREE_ME_SUPPORTED 1688 info_ptr->free_me |= PNG_FREE_ROWS; 1689#endif 1690 1691 for (row = 0; row < (int)info_ptr->height; row++) 1692 info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr, 1693 png_get_rowbytes(png_ptr, info_ptr)); 1694 } 1695 1696 png_read_image(png_ptr, info_ptr->row_pointers); 1697 info_ptr->valid |= PNG_INFO_IDAT; 1698 1699 /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */ 1700 png_read_end(png_ptr, info_ptr); 1701 1702 transforms = transforms; /* Quiet compiler warnings */ 1703 params = params; 1704 1705} 1706#endif /* PNG_INFO_IMAGE_SUPPORTED */ 1707#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ 1708#endif /* PNG_READ_SUPPORTED */ 1709