scroggo | 3965825 | 2016-06-02 12:59:59 -0700 | [diff] [blame] | 1 | |
| 2 | /* png.c - location for general purpose libpng functions |
| 3 | * |
| 4 | * Last changed in libpng 1.6.19 [November 12, 2015] |
| 5 | * Copyright (c) 1998-2002,2004,2006-2015 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 | #include "pngpriv.h" |
| 15 | |
| 16 | /* Generate a compiler error if there is an old png.h in the search path. */ |
| 17 | typedef png_libpng_version_1_6_22rc01 Your_png_h_is_not_version_1_6_22rc01; |
| 18 | |
| 19 | /* Tells libpng that we have already handled the first "num_bytes" bytes |
| 20 | * of the PNG file signature. If the PNG data is embedded into another |
| 21 | * stream we can set num_bytes = 8 so that libpng will not attempt to read |
| 22 | * or write any of the magic bytes before it starts on the IHDR. |
| 23 | */ |
| 24 | |
| 25 | #ifdef PNG_READ_SUPPORTED |
| 26 | void PNGAPI |
| 27 | png_set_sig_bytes(png_structrp png_ptr, int num_bytes) |
| 28 | { |
| 29 | unsigned int nb = (unsigned int)num_bytes; |
| 30 | |
| 31 | png_debug(1, "in png_set_sig_bytes"); |
| 32 | |
| 33 | if (png_ptr == NULL) |
| 34 | return; |
| 35 | |
| 36 | if (num_bytes < 0) |
| 37 | nb = 0; |
| 38 | |
| 39 | if (nb > 8) |
| 40 | png_error(png_ptr, "Too many bytes for PNG signature"); |
| 41 | |
| 42 | png_ptr->sig_bytes = (png_byte)nb; |
| 43 | } |
| 44 | |
| 45 | /* Checks whether the supplied bytes match the PNG signature. We allow |
| 46 | * checking less than the full 8-byte signature so that those apps that |
| 47 | * already read the first few bytes of a file to determine the file type |
| 48 | * can simply check the remaining bytes for extra assurance. Returns |
| 49 | * an integer less than, equal to, or greater than zero if sig is found, |
| 50 | * respectively, to be less than, to match, or be greater than the correct |
| 51 | * PNG signature (this is the same behavior as strcmp, memcmp, etc). |
| 52 | */ |
| 53 | int PNGAPI |
| 54 | png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check) |
| 55 | { |
| 56 | png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; |
| 57 | |
| 58 | if (num_to_check > 8) |
| 59 | num_to_check = 8; |
| 60 | |
| 61 | else if (num_to_check < 1) |
| 62 | return (-1); |
| 63 | |
| 64 | if (start > 7) |
| 65 | return (-1); |
| 66 | |
| 67 | if (start + num_to_check > 8) |
| 68 | num_to_check = 8 - start; |
| 69 | |
| 70 | return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check))); |
| 71 | } |
| 72 | |
| 73 | #endif /* READ */ |
| 74 | |
| 75 | #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) |
| 76 | /* Function to allocate memory for zlib */ |
| 77 | PNG_FUNCTION(voidpf /* PRIVATE */, |
| 78 | png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED) |
| 79 | { |
| 80 | png_alloc_size_t num_bytes = size; |
| 81 | |
| 82 | if (png_ptr == NULL) |
| 83 | return NULL; |
| 84 | |
| 85 | if (items >= (~(png_alloc_size_t)0)/size) |
| 86 | { |
| 87 | png_warning (png_voidcast(png_structrp, png_ptr), |
| 88 | "Potential overflow in png_zalloc()"); |
| 89 | return NULL; |
| 90 | } |
| 91 | |
| 92 | num_bytes *= items; |
| 93 | return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes); |
| 94 | } |
| 95 | |
| 96 | /* Function to free memory for zlib */ |
| 97 | void /* PRIVATE */ |
| 98 | png_zfree(voidpf png_ptr, voidpf ptr) |
| 99 | { |
| 100 | png_free(png_voidcast(png_const_structrp,png_ptr), ptr); |
| 101 | } |
| 102 | |
| 103 | /* Reset the CRC variable to 32 bits of 1's. Care must be taken |
| 104 | * in case CRC is > 32 bits to leave the top bits 0. |
| 105 | */ |
| 106 | void /* PRIVATE */ |
| 107 | png_reset_crc(png_structrp png_ptr) |
| 108 | { |
| 109 | /* The cast is safe because the crc is a 32-bit value. */ |
| 110 | png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0); |
| 111 | } |
| 112 | |
| 113 | /* Calculate the CRC over a section of data. We can only pass as |
| 114 | * much data to this routine as the largest single buffer size. We |
| 115 | * also check that this data will actually be used before going to the |
| 116 | * trouble of calculating it. |
| 117 | */ |
| 118 | void /* PRIVATE */ |
| 119 | png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length) |
| 120 | { |
| 121 | int need_crc = 1; |
| 122 | |
| 123 | if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0) |
| 124 | { |
| 125 | if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == |
| 126 | (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) |
| 127 | need_crc = 0; |
| 128 | } |
| 129 | |
| 130 | else /* critical */ |
| 131 | { |
| 132 | if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0) |
| 133 | need_crc = 0; |
| 134 | } |
| 135 | |
| 136 | /* 'uLong' is defined in zlib.h as unsigned long; this means that on some |
| 137 | * systems it is a 64-bit value. crc32, however, returns 32 bits so the |
| 138 | * following cast is safe. 'uInt' may be no more than 16 bits, so it is |
| 139 | * necessary to perform a loop here. |
| 140 | */ |
| 141 | if (need_crc != 0 && length > 0) |
| 142 | { |
| 143 | uLong crc = png_ptr->crc; /* Should never issue a warning */ |
| 144 | |
| 145 | do |
| 146 | { |
| 147 | uInt safe_length = (uInt)length; |
| 148 | #ifndef __COVERITY__ |
| 149 | if (safe_length == 0) |
| 150 | safe_length = (uInt)-1; /* evil, but safe */ |
| 151 | #endif |
| 152 | |
| 153 | crc = crc32(crc, ptr, safe_length); |
| 154 | |
| 155 | /* The following should never issue compiler warnings; if they do the |
| 156 | * target system has characteristics that will probably violate other |
| 157 | * assumptions within the libpng code. |
| 158 | */ |
| 159 | ptr += safe_length; |
| 160 | length -= safe_length; |
| 161 | } |
| 162 | while (length > 0); |
| 163 | |
| 164 | /* And the following is always safe because the crc is only 32 bits. */ |
| 165 | png_ptr->crc = (png_uint_32)crc; |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | /* Check a user supplied version number, called from both read and write |
| 170 | * functions that create a png_struct. |
| 171 | */ |
| 172 | int |
| 173 | png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver) |
| 174 | { |
| 175 | /* Libpng versions 1.0.0 and later are binary compatible if the version |
| 176 | * string matches through the second '.'; we must recompile any |
| 177 | * applications that use any older library version. |
| 178 | */ |
| 179 | |
| 180 | if (user_png_ver != NULL) |
| 181 | { |
| 182 | int i = -1; |
| 183 | int found_dots = 0; |
| 184 | |
| 185 | do |
| 186 | { |
| 187 | i++; |
| 188 | if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i]) |
| 189 | png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; |
| 190 | if (user_png_ver[i] == '.') |
| 191 | found_dots++; |
| 192 | } while (found_dots < 2 && user_png_ver[i] != 0 && |
| 193 | PNG_LIBPNG_VER_STRING[i] != 0); |
| 194 | } |
| 195 | |
| 196 | else |
| 197 | png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; |
| 198 | |
| 199 | if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0) |
| 200 | { |
| 201 | #ifdef PNG_WARNINGS_SUPPORTED |
| 202 | size_t pos = 0; |
| 203 | char m[128]; |
| 204 | |
| 205 | pos = png_safecat(m, (sizeof m), pos, |
| 206 | "Application built with libpng-"); |
| 207 | pos = png_safecat(m, (sizeof m), pos, user_png_ver); |
| 208 | pos = png_safecat(m, (sizeof m), pos, " but running with "); |
| 209 | pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING); |
| 210 | PNG_UNUSED(pos) |
| 211 | |
| 212 | png_warning(png_ptr, m); |
| 213 | #endif |
| 214 | |
| 215 | #ifdef PNG_ERROR_NUMBERS_SUPPORTED |
| 216 | png_ptr->flags = 0; |
| 217 | #endif |
| 218 | |
| 219 | return 0; |
| 220 | } |
| 221 | |
| 222 | /* Success return. */ |
| 223 | return 1; |
| 224 | } |
| 225 | |
| 226 | /* Generic function to create a png_struct for either read or write - this |
| 227 | * contains the common initialization. |
| 228 | */ |
| 229 | PNG_FUNCTION(png_structp /* PRIVATE */, |
| 230 | png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr, |
| 231 | png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, |
| 232 | png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) |
| 233 | { |
| 234 | png_struct create_struct; |
| 235 | # ifdef PNG_SETJMP_SUPPORTED |
| 236 | jmp_buf create_jmp_buf; |
| 237 | # endif |
| 238 | |
| 239 | /* This temporary stack-allocated structure is used to provide a place to |
| 240 | * build enough context to allow the user provided memory allocator (if any) |
| 241 | * to be called. |
| 242 | */ |
| 243 | memset(&create_struct, 0, (sizeof create_struct)); |
| 244 | |
| 245 | /* Added at libpng-1.2.6 */ |
| 246 | # ifdef PNG_USER_LIMITS_SUPPORTED |
| 247 | create_struct.user_width_max = PNG_USER_WIDTH_MAX; |
| 248 | create_struct.user_height_max = PNG_USER_HEIGHT_MAX; |
| 249 | |
| 250 | # ifdef PNG_USER_CHUNK_CACHE_MAX |
| 251 | /* Added at libpng-1.2.43 and 1.4.0 */ |
| 252 | create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX; |
| 253 | # endif |
| 254 | |
| 255 | # ifdef PNG_USER_CHUNK_MALLOC_MAX |
| 256 | /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists |
| 257 | * in png_struct regardless. |
| 258 | */ |
| 259 | create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX; |
| 260 | # endif |
| 261 | # endif |
| 262 | |
| 263 | /* The following two API calls simply set fields in png_struct, so it is safe |
| 264 | * to do them now even though error handling is not yet set up. |
| 265 | */ |
| 266 | # ifdef PNG_USER_MEM_SUPPORTED |
| 267 | png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn); |
| 268 | # else |
| 269 | PNG_UNUSED(mem_ptr) |
| 270 | PNG_UNUSED(malloc_fn) |
| 271 | PNG_UNUSED(free_fn) |
| 272 | # endif |
| 273 | |
| 274 | /* (*error_fn) can return control to the caller after the error_ptr is set, |
| 275 | * this will result in a memory leak unless the error_fn does something |
| 276 | * extremely sophisticated. The design lacks merit but is implicit in the |
| 277 | * API. |
| 278 | */ |
| 279 | png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn); |
| 280 | |
| 281 | # ifdef PNG_SETJMP_SUPPORTED |
| 282 | if (!setjmp(create_jmp_buf)) |
| 283 | # endif |
| 284 | { |
| 285 | # ifdef PNG_SETJMP_SUPPORTED |
| 286 | /* Temporarily fake out the longjmp information until we have |
| 287 | * successfully completed this function. This only works if we have |
| 288 | * setjmp() support compiled in, but it is safe - this stuff should |
| 289 | * never happen. |
| 290 | */ |
| 291 | create_struct.jmp_buf_ptr = &create_jmp_buf; |
| 292 | create_struct.jmp_buf_size = 0; /*stack allocation*/ |
| 293 | create_struct.longjmp_fn = longjmp; |
| 294 | # endif |
| 295 | /* Call the general version checker (shared with read and write code): |
| 296 | */ |
| 297 | if (png_user_version_check(&create_struct, user_png_ver) != 0) |
| 298 | { |
| 299 | png_structrp png_ptr = png_voidcast(png_structrp, |
| 300 | png_malloc_warn(&create_struct, (sizeof *png_ptr))); |
| 301 | |
| 302 | if (png_ptr != NULL) |
| 303 | { |
| 304 | /* png_ptr->zstream holds a back-pointer to the png_struct, so |
| 305 | * this can only be done now: |
| 306 | */ |
| 307 | create_struct.zstream.zalloc = png_zalloc; |
| 308 | create_struct.zstream.zfree = png_zfree; |
| 309 | create_struct.zstream.opaque = png_ptr; |
| 310 | |
| 311 | # ifdef PNG_SETJMP_SUPPORTED |
| 312 | /* Eliminate the local error handling: */ |
| 313 | create_struct.jmp_buf_ptr = NULL; |
| 314 | create_struct.jmp_buf_size = 0; |
| 315 | create_struct.longjmp_fn = 0; |
| 316 | # endif |
| 317 | |
| 318 | *png_ptr = create_struct; |
| 319 | |
| 320 | /* This is the successful return point */ |
| 321 | return png_ptr; |
| 322 | } |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | /* A longjmp because of a bug in the application storage allocator or a |
| 327 | * simple failure to allocate the png_struct. |
| 328 | */ |
| 329 | return NULL; |
| 330 | } |
| 331 | |
| 332 | /* Allocate the memory for an info_struct for the application. */ |
| 333 | PNG_FUNCTION(png_infop,PNGAPI |
| 334 | png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED) |
| 335 | { |
| 336 | png_inforp info_ptr; |
| 337 | |
| 338 | png_debug(1, "in png_create_info_struct"); |
| 339 | |
| 340 | if (png_ptr == NULL) |
| 341 | return NULL; |
| 342 | |
| 343 | /* Use the internal API that does not (or at least should not) error out, so |
| 344 | * that this call always returns ok. The application typically sets up the |
| 345 | * error handling *after* creating the info_struct because this is the way it |
| 346 | * has always been done in 'example.c'. |
| 347 | */ |
| 348 | info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr, |
| 349 | (sizeof *info_ptr))); |
| 350 | |
| 351 | if (info_ptr != NULL) |
| 352 | memset(info_ptr, 0, (sizeof *info_ptr)); |
| 353 | |
| 354 | return info_ptr; |
| 355 | } |
| 356 | |
| 357 | /* This function frees the memory associated with a single info struct. |
| 358 | * Normally, one would use either png_destroy_read_struct() or |
| 359 | * png_destroy_write_struct() to free an info struct, but this may be |
| 360 | * useful for some applications. From libpng 1.6.0 this function is also used |
| 361 | * internally to implement the png_info release part of the 'struct' destroy |
| 362 | * APIs. This ensures that all possible approaches free the same data (all of |
| 363 | * it). |
| 364 | */ |
| 365 | void PNGAPI |
| 366 | png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr) |
| 367 | { |
| 368 | png_inforp info_ptr = NULL; |
| 369 | |
| 370 | png_debug(1, "in png_destroy_info_struct"); |
| 371 | |
| 372 | if (png_ptr == NULL) |
| 373 | return; |
| 374 | |
| 375 | if (info_ptr_ptr != NULL) |
| 376 | info_ptr = *info_ptr_ptr; |
| 377 | |
| 378 | if (info_ptr != NULL) |
| 379 | { |
| 380 | /* Do this first in case of an error below; if the app implements its own |
| 381 | * memory management this can lead to png_free calling png_error, which |
| 382 | * will abort this routine and return control to the app error handler. |
| 383 | * An infinite loop may result if it then tries to free the same info |
| 384 | * ptr. |
| 385 | */ |
| 386 | *info_ptr_ptr = NULL; |
| 387 | |
| 388 | png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); |
| 389 | memset(info_ptr, 0, (sizeof *info_ptr)); |
| 390 | png_free(png_ptr, info_ptr); |
| 391 | } |
| 392 | } |
| 393 | |
| 394 | /* Initialize the info structure. This is now an internal function (0.89) |
| 395 | * and applications using it are urged to use png_create_info_struct() |
| 396 | * instead. Use deprecated in 1.6.0, internal use removed (used internally it |
| 397 | * is just a memset). |
| 398 | * |
| 399 | * NOTE: it is almost inconceivable that this API is used because it bypasses |
| 400 | * the user-memory mechanism and the user error handling/warning mechanisms in |
| 401 | * those cases where it does anything other than a memset. |
| 402 | */ |
| 403 | PNG_FUNCTION(void,PNGAPI |
| 404 | png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size), |
| 405 | PNG_DEPRECATED) |
| 406 | { |
| 407 | png_inforp info_ptr = *ptr_ptr; |
| 408 | |
| 409 | png_debug(1, "in png_info_init_3"); |
| 410 | |
| 411 | if (info_ptr == NULL) |
| 412 | return; |
| 413 | |
| 414 | if ((sizeof (png_info)) > png_info_struct_size) |
| 415 | { |
| 416 | *ptr_ptr = NULL; |
| 417 | /* The following line is why this API should not be used: */ |
| 418 | free(info_ptr); |
| 419 | info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL, |
| 420 | (sizeof *info_ptr))); |
| 421 | if (info_ptr == NULL) |
| 422 | return; |
| 423 | *ptr_ptr = info_ptr; |
| 424 | } |
| 425 | |
| 426 | /* Set everything to 0 */ |
| 427 | memset(info_ptr, 0, (sizeof *info_ptr)); |
| 428 | } |
| 429 | |
| 430 | /* The following API is not called internally */ |
| 431 | void PNGAPI |
| 432 | png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr, |
| 433 | int freer, png_uint_32 mask) |
| 434 | { |
| 435 | png_debug(1, "in png_data_freer"); |
| 436 | |
| 437 | if (png_ptr == NULL || info_ptr == NULL) |
| 438 | return; |
| 439 | |
| 440 | if (freer == PNG_DESTROY_WILL_FREE_DATA) |
| 441 | info_ptr->free_me |= mask; |
| 442 | |
| 443 | else if (freer == PNG_USER_WILL_FREE_DATA) |
| 444 | info_ptr->free_me &= ~mask; |
| 445 | |
| 446 | else |
| 447 | png_error(png_ptr, "Unknown freer parameter in png_data_freer"); |
| 448 | } |
| 449 | |
| 450 | void PNGAPI |
| 451 | png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask, |
| 452 | int num) |
| 453 | { |
| 454 | png_debug(1, "in png_free_data"); |
| 455 | |
| 456 | if (png_ptr == NULL || info_ptr == NULL) |
| 457 | return; |
| 458 | |
| 459 | #ifdef PNG_TEXT_SUPPORTED |
| 460 | /* Free text item num or (if num == -1) all text items */ |
| 461 | if (info_ptr->text != 0 && |
| 462 | ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0) |
| 463 | { |
| 464 | if (num != -1) |
| 465 | { |
| 466 | png_free(png_ptr, info_ptr->text[num].key); |
| 467 | info_ptr->text[num].key = NULL; |
| 468 | } |
| 469 | |
| 470 | else |
| 471 | { |
| 472 | int i; |
| 473 | |
| 474 | for (i = 0; i < info_ptr->num_text; i++) |
| 475 | png_free(png_ptr, info_ptr->text[i].key); |
| 476 | |
| 477 | png_free(png_ptr, info_ptr->text); |
| 478 | info_ptr->text = NULL; |
| 479 | info_ptr->num_text = 0; |
| 480 | } |
| 481 | } |
| 482 | #endif |
| 483 | |
| 484 | #ifdef PNG_tRNS_SUPPORTED |
| 485 | /* Free any tRNS entry */ |
| 486 | if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0) |
| 487 | { |
| 488 | info_ptr->valid &= ~PNG_INFO_tRNS; |
| 489 | png_free(png_ptr, info_ptr->trans_alpha); |
| 490 | info_ptr->trans_alpha = NULL; |
| 491 | info_ptr->num_trans = 0; |
| 492 | } |
| 493 | #endif |
| 494 | |
| 495 | #ifdef PNG_sCAL_SUPPORTED |
| 496 | /* Free any sCAL entry */ |
| 497 | if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0) |
| 498 | { |
| 499 | png_free(png_ptr, info_ptr->scal_s_width); |
| 500 | png_free(png_ptr, info_ptr->scal_s_height); |
| 501 | info_ptr->scal_s_width = NULL; |
| 502 | info_ptr->scal_s_height = NULL; |
| 503 | info_ptr->valid &= ~PNG_INFO_sCAL; |
| 504 | } |
| 505 | #endif |
| 506 | |
| 507 | #ifdef PNG_pCAL_SUPPORTED |
| 508 | /* Free any pCAL entry */ |
| 509 | if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0) |
| 510 | { |
| 511 | png_free(png_ptr, info_ptr->pcal_purpose); |
| 512 | png_free(png_ptr, info_ptr->pcal_units); |
| 513 | info_ptr->pcal_purpose = NULL; |
| 514 | info_ptr->pcal_units = NULL; |
| 515 | |
| 516 | if (info_ptr->pcal_params != NULL) |
| 517 | { |
| 518 | int i; |
| 519 | |
| 520 | for (i = 0; i < info_ptr->pcal_nparams; i++) |
| 521 | png_free(png_ptr, info_ptr->pcal_params[i]); |
| 522 | |
| 523 | png_free(png_ptr, info_ptr->pcal_params); |
| 524 | info_ptr->pcal_params = NULL; |
| 525 | } |
| 526 | info_ptr->valid &= ~PNG_INFO_pCAL; |
| 527 | } |
| 528 | #endif |
| 529 | |
| 530 | #ifdef PNG_iCCP_SUPPORTED |
| 531 | /* Free any profile entry */ |
| 532 | if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0) |
| 533 | { |
| 534 | png_free(png_ptr, info_ptr->iccp_name); |
| 535 | png_free(png_ptr, info_ptr->iccp_profile); |
| 536 | info_ptr->iccp_name = NULL; |
| 537 | info_ptr->iccp_profile = NULL; |
| 538 | info_ptr->valid &= ~PNG_INFO_iCCP; |
| 539 | } |
| 540 | #endif |
| 541 | |
| 542 | #ifdef PNG_sPLT_SUPPORTED |
| 543 | /* Free a given sPLT entry, or (if num == -1) all sPLT entries */ |
| 544 | if (info_ptr->splt_palettes != 0 && |
| 545 | ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0) |
| 546 | { |
| 547 | if (num != -1) |
| 548 | { |
| 549 | png_free(png_ptr, info_ptr->splt_palettes[num].name); |
| 550 | png_free(png_ptr, info_ptr->splt_palettes[num].entries); |
| 551 | info_ptr->splt_palettes[num].name = NULL; |
| 552 | info_ptr->splt_palettes[num].entries = NULL; |
| 553 | } |
| 554 | |
| 555 | else |
| 556 | { |
| 557 | int i; |
| 558 | |
| 559 | for (i = 0; i < info_ptr->splt_palettes_num; i++) |
| 560 | { |
| 561 | png_free(png_ptr, info_ptr->splt_palettes[i].name); |
| 562 | png_free(png_ptr, info_ptr->splt_palettes[i].entries); |
| 563 | } |
| 564 | |
| 565 | png_free(png_ptr, info_ptr->splt_palettes); |
| 566 | info_ptr->splt_palettes = NULL; |
| 567 | info_ptr->splt_palettes_num = 0; |
| 568 | info_ptr->valid &= ~PNG_INFO_sPLT; |
| 569 | } |
| 570 | } |
| 571 | #endif |
| 572 | |
| 573 | #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED |
| 574 | if (info_ptr->unknown_chunks != 0 && |
| 575 | ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0) |
| 576 | { |
| 577 | if (num != -1) |
| 578 | { |
| 579 | png_free(png_ptr, info_ptr->unknown_chunks[num].data); |
| 580 | info_ptr->unknown_chunks[num].data = NULL; |
| 581 | } |
| 582 | |
| 583 | else |
| 584 | { |
| 585 | int i; |
| 586 | |
| 587 | for (i = 0; i < info_ptr->unknown_chunks_num; i++) |
| 588 | png_free(png_ptr, info_ptr->unknown_chunks[i].data); |
| 589 | |
| 590 | png_free(png_ptr, info_ptr->unknown_chunks); |
| 591 | info_ptr->unknown_chunks = NULL; |
| 592 | info_ptr->unknown_chunks_num = 0; |
| 593 | } |
| 594 | } |
| 595 | #endif |
| 596 | |
| 597 | #ifdef PNG_hIST_SUPPORTED |
| 598 | /* Free any hIST entry */ |
| 599 | if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0) |
| 600 | { |
| 601 | png_free(png_ptr, info_ptr->hist); |
| 602 | info_ptr->hist = NULL; |
| 603 | info_ptr->valid &= ~PNG_INFO_hIST; |
| 604 | } |
| 605 | #endif |
| 606 | |
| 607 | /* Free any PLTE entry that was internally allocated */ |
| 608 | if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0) |
| 609 | { |
| 610 | png_free(png_ptr, info_ptr->palette); |
| 611 | info_ptr->palette = NULL; |
| 612 | info_ptr->valid &= ~PNG_INFO_PLTE; |
| 613 | info_ptr->num_palette = 0; |
| 614 | } |
| 615 | |
| 616 | #ifdef PNG_INFO_IMAGE_SUPPORTED |
| 617 | /* Free any image bits attached to the info structure */ |
| 618 | if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0) |
| 619 | { |
| 620 | if (info_ptr->row_pointers != 0) |
| 621 | { |
| 622 | png_uint_32 row; |
| 623 | for (row = 0; row < info_ptr->height; row++) |
| 624 | png_free(png_ptr, info_ptr->row_pointers[row]); |
| 625 | |
| 626 | png_free(png_ptr, info_ptr->row_pointers); |
| 627 | info_ptr->row_pointers = NULL; |
| 628 | } |
| 629 | info_ptr->valid &= ~PNG_INFO_IDAT; |
| 630 | } |
| 631 | #endif |
| 632 | |
| 633 | if (num != -1) |
| 634 | mask &= ~PNG_FREE_MUL; |
| 635 | |
| 636 | info_ptr->free_me &= ~mask; |
| 637 | } |
| 638 | #endif /* READ || WRITE */ |
| 639 | |
| 640 | /* This function returns a pointer to the io_ptr associated with the user |
| 641 | * functions. The application should free any memory associated with this |
| 642 | * pointer before png_write_destroy() or png_read_destroy() are called. |
| 643 | */ |
| 644 | png_voidp PNGAPI |
| 645 | png_get_io_ptr(png_const_structrp png_ptr) |
| 646 | { |
| 647 | if (png_ptr == NULL) |
| 648 | return (NULL); |
| 649 | |
| 650 | return (png_ptr->io_ptr); |
| 651 | } |
| 652 | |
| 653 | #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) |
| 654 | # ifdef PNG_STDIO_SUPPORTED |
| 655 | /* Initialize the default input/output functions for the PNG file. If you |
| 656 | * use your own read or write routines, you can call either png_set_read_fn() |
| 657 | * or png_set_write_fn() instead of png_init_io(). If you have defined |
| 658 | * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a |
| 659 | * function of your own because "FILE *" isn't necessarily available. |
| 660 | */ |
| 661 | void PNGAPI |
| 662 | png_init_io(png_structrp png_ptr, png_FILE_p fp) |
| 663 | { |
| 664 | png_debug(1, "in png_init_io"); |
| 665 | |
| 666 | if (png_ptr == NULL) |
| 667 | return; |
| 668 | |
| 669 | png_ptr->io_ptr = (png_voidp)fp; |
| 670 | } |
| 671 | # endif |
| 672 | |
| 673 | # ifdef PNG_SAVE_INT_32_SUPPORTED |
| 674 | /* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90 |
| 675 | * defines a cast of a signed integer to an unsigned integer either to preserve |
| 676 | * the value, if it is positive, or to calculate: |
| 677 | * |
| 678 | * (UNSIGNED_MAX+1) + integer |
| 679 | * |
| 680 | * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the |
| 681 | * negative integral value is added the result will be an unsigned value |
| 682 | * correspnding to the 2's complement representation. |
| 683 | */ |
| 684 | void PNGAPI |
| 685 | png_save_int_32(png_bytep buf, png_int_32 i) |
| 686 | { |
| 687 | png_save_uint_32(buf, i); |
| 688 | } |
| 689 | # endif |
| 690 | |
| 691 | # ifdef PNG_TIME_RFC1123_SUPPORTED |
| 692 | /* Convert the supplied time into an RFC 1123 string suitable for use in |
| 693 | * a "Creation Time" or other text-based time string. |
| 694 | */ |
| 695 | int PNGAPI |
| 696 | png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime) |
| 697 | { |
| 698 | static PNG_CONST char short_months[12][4] = |
| 699 | {"Jan", "Feb", "Mar", "Apr", "May", "Jun", |
| 700 | "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; |
| 701 | |
| 702 | if (out == NULL) |
| 703 | return 0; |
| 704 | |
| 705 | if (ptime->year > 9999 /* RFC1123 limitation */ || |
| 706 | ptime->month == 0 || ptime->month > 12 || |
| 707 | ptime->day == 0 || ptime->day > 31 || |
| 708 | ptime->hour > 23 || ptime->minute > 59 || |
| 709 | ptime->second > 60) |
| 710 | return 0; |
| 711 | |
| 712 | { |
| 713 | size_t pos = 0; |
| 714 | char number_buf[5]; /* enough for a four-digit year */ |
| 715 | |
| 716 | # define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string)) |
| 717 | # define APPEND_NUMBER(format, value)\ |
| 718 | APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value))) |
| 719 | # define APPEND(ch) if (pos < 28) out[pos++] = (ch) |
| 720 | |
| 721 | APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day); |
| 722 | APPEND(' '); |
| 723 | APPEND_STRING(short_months[(ptime->month - 1)]); |
| 724 | APPEND(' '); |
| 725 | APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year); |
| 726 | APPEND(' '); |
| 727 | APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour); |
| 728 | APPEND(':'); |
| 729 | APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute); |
| 730 | APPEND(':'); |
| 731 | APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second); |
| 732 | APPEND_STRING(" +0000"); /* This reliably terminates the buffer */ |
| 733 | PNG_UNUSED (pos) |
| 734 | |
| 735 | # undef APPEND |
| 736 | # undef APPEND_NUMBER |
| 737 | # undef APPEND_STRING |
| 738 | } |
| 739 | |
| 740 | return 1; |
| 741 | } |
| 742 | |
| 743 | # if PNG_LIBPNG_VER < 10700 |
| 744 | /* To do: remove the following from libpng-1.7 */ |
| 745 | /* Original API that uses a private buffer in png_struct. |
| 746 | * Deprecated because it causes png_struct to carry a spurious temporary |
| 747 | * buffer (png_struct::time_buffer), better to have the caller pass this in. |
| 748 | */ |
| 749 | png_const_charp PNGAPI |
| 750 | png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime) |
| 751 | { |
| 752 | if (png_ptr != NULL) |
| 753 | { |
| 754 | /* The only failure above if png_ptr != NULL is from an invalid ptime */ |
| 755 | if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0) |
| 756 | png_warning(png_ptr, "Ignoring invalid time value"); |
| 757 | |
| 758 | else |
| 759 | return png_ptr->time_buffer; |
| 760 | } |
| 761 | |
| 762 | return NULL; |
| 763 | } |
| 764 | # endif /* LIBPNG_VER < 10700 */ |
| 765 | # endif /* TIME_RFC1123 */ |
| 766 | |
| 767 | #endif /* READ || WRITE */ |
| 768 | |
| 769 | png_const_charp PNGAPI |
| 770 | png_get_copyright(png_const_structrp png_ptr) |
| 771 | { |
| 772 | PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ |
| 773 | #ifdef PNG_STRING_COPYRIGHT |
| 774 | return PNG_STRING_COPYRIGHT |
| 775 | #else |
| 776 | # ifdef __STDC__ |
| 777 | return PNG_STRING_NEWLINE \ |
| 778 | "libpng version 1.6.22rc01 - May 14, 2016" PNG_STRING_NEWLINE \ |
| 779 | "Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson" \ |
| 780 | PNG_STRING_NEWLINE \ |
| 781 | "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ |
| 782 | "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ |
| 783 | PNG_STRING_NEWLINE; |
| 784 | # else |
| 785 | return "libpng version 1.6.22rc01 - May 14, 2016\ |
| 786 | Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\ |
| 787 | Copyright (c) 1996-1997 Andreas Dilger\ |
| 788 | Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."; |
| 789 | # endif |
| 790 | #endif |
| 791 | } |
| 792 | |
| 793 | /* The following return the library version as a short string in the |
| 794 | * format 1.0.0 through 99.99.99zz. To get the version of *.h files |
| 795 | * used with your application, print out PNG_LIBPNG_VER_STRING, which |
| 796 | * is defined in png.h. |
| 797 | * Note: now there is no difference between png_get_libpng_ver() and |
| 798 | * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard, |
| 799 | * it is guaranteed that png.c uses the correct version of png.h. |
| 800 | */ |
| 801 | png_const_charp PNGAPI |
| 802 | png_get_libpng_ver(png_const_structrp png_ptr) |
| 803 | { |
| 804 | /* Version of *.c files used when building libpng */ |
| 805 | return png_get_header_ver(png_ptr); |
| 806 | } |
| 807 | |
| 808 | png_const_charp PNGAPI |
| 809 | png_get_header_ver(png_const_structrp png_ptr) |
| 810 | { |
| 811 | /* Version of *.h files used when building libpng */ |
| 812 | PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ |
| 813 | return PNG_LIBPNG_VER_STRING; |
| 814 | } |
| 815 | |
| 816 | png_const_charp PNGAPI |
| 817 | png_get_header_version(png_const_structrp png_ptr) |
| 818 | { |
| 819 | /* Returns longer string containing both version and date */ |
| 820 | PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ |
| 821 | #ifdef __STDC__ |
| 822 | return PNG_HEADER_VERSION_STRING |
| 823 | # ifndef PNG_READ_SUPPORTED |
| 824 | " (NO READ SUPPORT)" |
| 825 | # endif |
| 826 | PNG_STRING_NEWLINE; |
| 827 | #else |
| 828 | return PNG_HEADER_VERSION_STRING; |
| 829 | #endif |
| 830 | } |
| 831 | |
| 832 | #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED |
| 833 | /* NOTE: this routine is not used internally! */ |
| 834 | /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth |
| 835 | * large of png_color. This lets grayscale images be treated as |
| 836 | * paletted. Most useful for gamma correction and simplification |
| 837 | * of code. This API is not used internally. |
| 838 | */ |
| 839 | void PNGAPI |
| 840 | png_build_grayscale_palette(int bit_depth, png_colorp palette) |
| 841 | { |
| 842 | int num_palette; |
| 843 | int color_inc; |
| 844 | int i; |
| 845 | int v; |
| 846 | |
| 847 | png_debug(1, "in png_do_build_grayscale_palette"); |
| 848 | |
| 849 | if (palette == NULL) |
| 850 | return; |
| 851 | |
| 852 | switch (bit_depth) |
| 853 | { |
| 854 | case 1: |
| 855 | num_palette = 2; |
| 856 | color_inc = 0xff; |
| 857 | break; |
| 858 | |
| 859 | case 2: |
| 860 | num_palette = 4; |
| 861 | color_inc = 0x55; |
| 862 | break; |
| 863 | |
| 864 | case 4: |
| 865 | num_palette = 16; |
| 866 | color_inc = 0x11; |
| 867 | break; |
| 868 | |
| 869 | case 8: |
| 870 | num_palette = 256; |
| 871 | color_inc = 1; |
| 872 | break; |
| 873 | |
| 874 | default: |
| 875 | num_palette = 0; |
| 876 | color_inc = 0; |
| 877 | break; |
| 878 | } |
| 879 | |
| 880 | for (i = 0, v = 0; i < num_palette; i++, v += color_inc) |
| 881 | { |
| 882 | palette[i].red = (png_byte)(v & 0xff); |
| 883 | palette[i].green = (png_byte)(v & 0xff); |
| 884 | palette[i].blue = (png_byte)(v & 0xff); |
| 885 | } |
| 886 | } |
| 887 | #endif |
| 888 | |
| 889 | #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED |
| 890 | int PNGAPI |
| 891 | png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name) |
| 892 | { |
| 893 | /* Check chunk_name and return "keep" value if it's on the list, else 0 */ |
| 894 | png_const_bytep p, p_end; |
| 895 | |
| 896 | if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0) |
| 897 | return PNG_HANDLE_CHUNK_AS_DEFAULT; |
| 898 | |
| 899 | p_end = png_ptr->chunk_list; |
| 900 | p = p_end + png_ptr->num_chunk_list*5; /* beyond end */ |
| 901 | |
| 902 | /* The code is the fifth byte after each four byte string. Historically this |
| 903 | * code was always searched from the end of the list, this is no longer |
| 904 | * necessary because the 'set' routine handles duplicate entries correcty. |
| 905 | */ |
| 906 | do /* num_chunk_list > 0, so at least one */ |
| 907 | { |
| 908 | p -= 5; |
| 909 | |
| 910 | if (memcmp(chunk_name, p, 4) == 0) |
| 911 | return p[4]; |
| 912 | } |
| 913 | while (p > p_end); |
| 914 | |
| 915 | /* This means that known chunks should be processed and unknown chunks should |
| 916 | * be handled according to the value of png_ptr->unknown_default; this can be |
| 917 | * confusing because, as a result, there are two levels of defaulting for |
| 918 | * unknown chunks. |
| 919 | */ |
| 920 | return PNG_HANDLE_CHUNK_AS_DEFAULT; |
| 921 | } |
| 922 | |
| 923 | #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\ |
| 924 | defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED) |
| 925 | int /* PRIVATE */ |
| 926 | png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name) |
| 927 | { |
| 928 | png_byte chunk_string[5]; |
| 929 | |
| 930 | PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name); |
| 931 | return png_handle_as_unknown(png_ptr, chunk_string); |
| 932 | } |
| 933 | #endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */ |
| 934 | #endif /* SET_UNKNOWN_CHUNKS */ |
| 935 | |
| 936 | #ifdef PNG_READ_SUPPORTED |
| 937 | /* This function, added to libpng-1.0.6g, is untested. */ |
| 938 | int PNGAPI |
| 939 | png_reset_zstream(png_structrp png_ptr) |
| 940 | { |
| 941 | if (png_ptr == NULL) |
| 942 | return Z_STREAM_ERROR; |
| 943 | |
| 944 | /* WARNING: this resets the window bits to the maximum! */ |
| 945 | return (inflateReset(&png_ptr->zstream)); |
| 946 | } |
| 947 | #endif /* READ */ |
| 948 | |
| 949 | /* This function was added to libpng-1.0.7 */ |
| 950 | png_uint_32 PNGAPI |
| 951 | png_access_version_number(void) |
| 952 | { |
| 953 | /* Version of *.c files used when building libpng */ |
| 954 | return((png_uint_32)PNG_LIBPNG_VER); |
| 955 | } |
| 956 | |
| 957 | #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) |
| 958 | /* Ensure that png_ptr->zstream.msg holds some appropriate error message string. |
| 959 | * If it doesn't 'ret' is used to set it to something appropriate, even in cases |
| 960 | * like Z_OK or Z_STREAM_END where the error code is apparently a success code. |
| 961 | */ |
| 962 | void /* PRIVATE */ |
| 963 | png_zstream_error(png_structrp png_ptr, int ret) |
| 964 | { |
| 965 | /* Translate 'ret' into an appropriate error string, priority is given to the |
| 966 | * one in zstream if set. This always returns a string, even in cases like |
| 967 | * Z_OK or Z_STREAM_END where the error code is a success code. |
| 968 | */ |
| 969 | if (png_ptr->zstream.msg == NULL) switch (ret) |
| 970 | { |
| 971 | default: |
| 972 | case Z_OK: |
| 973 | png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code"); |
| 974 | break; |
| 975 | |
| 976 | case Z_STREAM_END: |
| 977 | /* Normal exit */ |
| 978 | png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream"); |
| 979 | break; |
| 980 | |
| 981 | case Z_NEED_DICT: |
| 982 | /* This means the deflate stream did not have a dictionary; this |
| 983 | * indicates a bogus PNG. |
| 984 | */ |
| 985 | png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary"); |
| 986 | break; |
| 987 | |
| 988 | case Z_ERRNO: |
| 989 | /* gz APIs only: should not happen */ |
| 990 | png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error"); |
| 991 | break; |
| 992 | |
| 993 | case Z_STREAM_ERROR: |
| 994 | /* internal libpng error */ |
| 995 | png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib"); |
| 996 | break; |
| 997 | |
| 998 | case Z_DATA_ERROR: |
| 999 | png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream"); |
| 1000 | break; |
| 1001 | |
| 1002 | case Z_MEM_ERROR: |
| 1003 | png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory"); |
| 1004 | break; |
| 1005 | |
| 1006 | case Z_BUF_ERROR: |
| 1007 | /* End of input or output; not a problem if the caller is doing |
| 1008 | * incremental read or write. |
| 1009 | */ |
| 1010 | png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated"); |
| 1011 | break; |
| 1012 | |
| 1013 | case Z_VERSION_ERROR: |
| 1014 | png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version"); |
| 1015 | break; |
| 1016 | |
| 1017 | case PNG_UNEXPECTED_ZLIB_RETURN: |
| 1018 | /* Compile errors here mean that zlib now uses the value co-opted in |
| 1019 | * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above |
| 1020 | * and change pngpriv.h. Note that this message is "... return", |
| 1021 | * whereas the default/Z_OK one is "... return code". |
| 1022 | */ |
| 1023 | png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return"); |
| 1024 | break; |
| 1025 | } |
| 1026 | } |
| 1027 | |
| 1028 | /* png_convert_size: a PNGAPI but no longer in png.h, so deleted |
| 1029 | * at libpng 1.5.5! |
| 1030 | */ |
| 1031 | |
| 1032 | /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ |
| 1033 | #ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */ |
| 1034 | static int |
| 1035 | png_colorspace_check_gamma(png_const_structrp png_ptr, |
| 1036 | png_colorspacerp colorspace, png_fixed_point gAMA, int from) |
| 1037 | /* This is called to check a new gamma value against an existing one. The |
| 1038 | * routine returns false if the new gamma value should not be written. |
| 1039 | * |
| 1040 | * 'from' says where the new gamma value comes from: |
| 1041 | * |
| 1042 | * 0: the new gamma value is the libpng estimate for an ICC profile |
| 1043 | * 1: the new gamma value comes from a gAMA chunk |
| 1044 | * 2: the new gamma value comes from an sRGB chunk |
| 1045 | */ |
| 1046 | { |
| 1047 | png_fixed_point gtest; |
| 1048 | |
| 1049 | if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 && |
| 1050 | (png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) == 0 || |
| 1051 | png_gamma_significant(gtest) != 0)) |
| 1052 | { |
| 1053 | /* Either this is an sRGB image, in which case the calculated gamma |
| 1054 | * approximation should match, or this is an image with a profile and the |
| 1055 | * value libpng calculates for the gamma of the profile does not match the |
| 1056 | * value recorded in the file. The former, sRGB, case is an error, the |
| 1057 | * latter is just a warning. |
| 1058 | */ |
| 1059 | if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2) |
| 1060 | { |
| 1061 | png_chunk_report(png_ptr, "gamma value does not match sRGB", |
| 1062 | PNG_CHUNK_ERROR); |
| 1063 | /* Do not overwrite an sRGB value */ |
| 1064 | return from == 2; |
| 1065 | } |
| 1066 | |
| 1067 | else /* sRGB tag not involved */ |
| 1068 | { |
| 1069 | png_chunk_report(png_ptr, "gamma value does not match libpng estimate", |
| 1070 | PNG_CHUNK_WARNING); |
| 1071 | return from == 1; |
| 1072 | } |
| 1073 | } |
| 1074 | |
| 1075 | return 1; |
| 1076 | } |
| 1077 | |
| 1078 | void /* PRIVATE */ |
| 1079 | png_colorspace_set_gamma(png_const_structrp png_ptr, |
| 1080 | png_colorspacerp colorspace, png_fixed_point gAMA) |
| 1081 | { |
| 1082 | /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't |
| 1083 | * occur. Since the fixed point representation is asymetrical it is |
| 1084 | * possible for 1/gamma to overflow the limit of 21474 and this means the |
| 1085 | * gamma value must be at least 5/100000 and hence at most 20000.0. For |
| 1086 | * safety the limits here are a little narrower. The values are 0.00016 to |
| 1087 | * 6250.0, which are truly ridiculous gamma values (and will produce |
| 1088 | * displays that are all black or all white.) |
| 1089 | * |
| 1090 | * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk |
| 1091 | * handling code, which only required the value to be >0. |
| 1092 | */ |
| 1093 | png_const_charp errmsg; |
| 1094 | |
| 1095 | if (gAMA < 16 || gAMA > 625000000) |
| 1096 | errmsg = "gamma value out of range"; |
| 1097 | |
| 1098 | # ifdef PNG_READ_gAMA_SUPPORTED |
| 1099 | /* Allow the application to set the gamma value more than once */ |
| 1100 | else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && |
| 1101 | (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0) |
| 1102 | errmsg = "duplicate"; |
| 1103 | # endif |
| 1104 | |
| 1105 | /* Do nothing if the colorspace is already invalid */ |
| 1106 | else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0) |
| 1107 | return; |
| 1108 | |
| 1109 | else |
| 1110 | { |
| 1111 | if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA, |
| 1112 | 1/*from gAMA*/) != 0) |
| 1113 | { |
| 1114 | /* Store this gamma value. */ |
| 1115 | colorspace->gamma = gAMA; |
| 1116 | colorspace->flags |= |
| 1117 | (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA); |
| 1118 | } |
| 1119 | |
| 1120 | /* At present if the check_gamma test fails the gamma of the colorspace is |
| 1121 | * not updated however the colorspace is not invalidated. This |
| 1122 | * corresponds to the case where the existing gamma comes from an sRGB |
| 1123 | * chunk or profile. An error message has already been output. |
| 1124 | */ |
| 1125 | return; |
| 1126 | } |
| 1127 | |
| 1128 | /* Error exit - errmsg has been set. */ |
| 1129 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1130 | png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR); |
| 1131 | } |
| 1132 | |
| 1133 | void /* PRIVATE */ |
| 1134 | png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr) |
| 1135 | { |
| 1136 | if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0) |
| 1137 | { |
| 1138 | /* Everything is invalid */ |
| 1139 | info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB| |
| 1140 | PNG_INFO_iCCP); |
| 1141 | |
| 1142 | # ifdef PNG_COLORSPACE_SUPPORTED |
| 1143 | /* Clean up the iCCP profile now if it won't be used. */ |
| 1144 | png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/); |
| 1145 | # else |
| 1146 | PNG_UNUSED(png_ptr) |
| 1147 | # endif |
| 1148 | } |
| 1149 | |
| 1150 | else |
| 1151 | { |
| 1152 | # ifdef PNG_COLORSPACE_SUPPORTED |
| 1153 | /* Leave the INFO_iCCP flag set if the pngset.c code has already set |
| 1154 | * it; this allows a PNG to contain a profile which matches sRGB and |
| 1155 | * yet still have that profile retrievable by the application. |
| 1156 | */ |
| 1157 | if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0) |
| 1158 | info_ptr->valid |= PNG_INFO_sRGB; |
| 1159 | |
| 1160 | else |
| 1161 | info_ptr->valid &= ~PNG_INFO_sRGB; |
| 1162 | |
| 1163 | if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0) |
| 1164 | info_ptr->valid |= PNG_INFO_cHRM; |
| 1165 | |
| 1166 | else |
| 1167 | info_ptr->valid &= ~PNG_INFO_cHRM; |
| 1168 | # endif |
| 1169 | |
| 1170 | if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0) |
| 1171 | info_ptr->valid |= PNG_INFO_gAMA; |
| 1172 | |
| 1173 | else |
| 1174 | info_ptr->valid &= ~PNG_INFO_gAMA; |
| 1175 | } |
| 1176 | } |
| 1177 | |
| 1178 | #ifdef PNG_READ_SUPPORTED |
| 1179 | void /* PRIVATE */ |
| 1180 | png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr) |
| 1181 | { |
| 1182 | if (info_ptr == NULL) /* reduce code size; check here not in the caller */ |
| 1183 | return; |
| 1184 | |
| 1185 | info_ptr->colorspace = png_ptr->colorspace; |
| 1186 | png_colorspace_sync_info(png_ptr, info_ptr); |
| 1187 | } |
| 1188 | #endif |
| 1189 | #endif /* GAMMA */ |
| 1190 | |
| 1191 | #ifdef PNG_COLORSPACE_SUPPORTED |
| 1192 | /* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for |
| 1193 | * cHRM, as opposed to using chromaticities. These internal APIs return |
| 1194 | * non-zero on a parameter error. The X, Y and Z values are required to be |
| 1195 | * positive and less than 1.0. |
| 1196 | */ |
| 1197 | static int |
| 1198 | png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ) |
| 1199 | { |
| 1200 | png_int_32 d, dwhite, whiteX, whiteY; |
| 1201 | |
| 1202 | d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z; |
| 1203 | if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0) |
| 1204 | return 1; |
| 1205 | if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0) |
| 1206 | return 1; |
| 1207 | dwhite = d; |
| 1208 | whiteX = XYZ->red_X; |
| 1209 | whiteY = XYZ->red_Y; |
| 1210 | |
| 1211 | d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z; |
| 1212 | if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0) |
| 1213 | return 1; |
| 1214 | if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0) |
| 1215 | return 1; |
| 1216 | dwhite += d; |
| 1217 | whiteX += XYZ->green_X; |
| 1218 | whiteY += XYZ->green_Y; |
| 1219 | |
| 1220 | d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z; |
| 1221 | if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0) |
| 1222 | return 1; |
| 1223 | if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0) |
| 1224 | return 1; |
| 1225 | dwhite += d; |
| 1226 | whiteX += XYZ->blue_X; |
| 1227 | whiteY += XYZ->blue_Y; |
| 1228 | |
| 1229 | /* The reference white is simply the sum of the end-point (X,Y,Z) vectors, |
| 1230 | * thus: |
| 1231 | */ |
| 1232 | if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0) |
| 1233 | return 1; |
| 1234 | if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0) |
| 1235 | return 1; |
| 1236 | |
| 1237 | return 0; |
| 1238 | } |
| 1239 | |
| 1240 | static int |
| 1241 | png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy) |
| 1242 | { |
| 1243 | png_fixed_point red_inverse, green_inverse, blue_scale; |
| 1244 | png_fixed_point left, right, denominator; |
| 1245 | |
| 1246 | /* Check xy and, implicitly, z. Note that wide gamut color spaces typically |
| 1247 | * have end points with 0 tristimulus values (these are impossible end |
| 1248 | * points, but they are used to cover the possible colors). We check |
| 1249 | * xy->whitey against 5, not 0, to avoid a possible integer overflow. |
| 1250 | */ |
| 1251 | if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1; |
| 1252 | if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1; |
| 1253 | if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1; |
| 1254 | if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1; |
| 1255 | if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1; |
| 1256 | if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1; |
| 1257 | if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1; |
| 1258 | if (xy->whitey < 5 || xy->whitey > PNG_FP_1-xy->whitex) return 1; |
| 1259 | |
| 1260 | /* The reverse calculation is more difficult because the original tristimulus |
| 1261 | * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8 |
| 1262 | * derived values were recorded in the cHRM chunk; |
| 1263 | * (red,green,blue,white)x(x,y). This loses one degree of freedom and |
| 1264 | * therefore an arbitrary ninth value has to be introduced to undo the |
| 1265 | * original transformations. |
| 1266 | * |
| 1267 | * Think of the original end-points as points in (X,Y,Z) space. The |
| 1268 | * chromaticity values (c) have the property: |
| 1269 | * |
| 1270 | * C |
| 1271 | * c = --------- |
| 1272 | * X + Y + Z |
| 1273 | * |
| 1274 | * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the |
| 1275 | * three chromaticity values (x,y,z) for each end-point obey the |
| 1276 | * relationship: |
| 1277 | * |
| 1278 | * x + y + z = 1 |
| 1279 | * |
| 1280 | * This describes the plane in (X,Y,Z) space that intersects each axis at the |
| 1281 | * value 1.0; call this the chromaticity plane. Thus the chromaticity |
| 1282 | * calculation has scaled each end-point so that it is on the x+y+z=1 plane |
| 1283 | * and chromaticity is the intersection of the vector from the origin to the |
| 1284 | * (X,Y,Z) value with the chromaticity plane. |
| 1285 | * |
| 1286 | * To fully invert the chromaticity calculation we would need the three |
| 1287 | * end-point scale factors, (red-scale, green-scale, blue-scale), but these |
| 1288 | * were not recorded. Instead we calculated the reference white (X,Y,Z) and |
| 1289 | * recorded the chromaticity of this. The reference white (X,Y,Z) would have |
| 1290 | * given all three of the scale factors since: |
| 1291 | * |
| 1292 | * color-C = color-c * color-scale |
| 1293 | * white-C = red-C + green-C + blue-C |
| 1294 | * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale |
| 1295 | * |
| 1296 | * But cHRM records only white-x and white-y, so we have lost the white scale |
| 1297 | * factor: |
| 1298 | * |
| 1299 | * white-C = white-c*white-scale |
| 1300 | * |
| 1301 | * To handle this the inverse transformation makes an arbitrary assumption |
| 1302 | * about white-scale: |
| 1303 | * |
| 1304 | * Assume: white-Y = 1.0 |
| 1305 | * Hence: white-scale = 1/white-y |
| 1306 | * Or: red-Y + green-Y + blue-Y = 1.0 |
| 1307 | * |
| 1308 | * Notice the last statement of the assumption gives an equation in three of |
| 1309 | * the nine values we want to calculate. 8 more equations come from the |
| 1310 | * above routine as summarised at the top above (the chromaticity |
| 1311 | * calculation): |
| 1312 | * |
| 1313 | * Given: color-x = color-X / (color-X + color-Y + color-Z) |
| 1314 | * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0 |
| 1315 | * |
| 1316 | * This is 9 simultaneous equations in the 9 variables "color-C" and can be |
| 1317 | * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix |
| 1318 | * determinants, however this is not as bad as it seems because only 28 of |
| 1319 | * the total of 90 terms in the various matrices are non-zero. Nevertheless |
| 1320 | * Cramer's rule is notoriously numerically unstable because the determinant |
| 1321 | * calculation involves the difference of large, but similar, numbers. It is |
| 1322 | * difficult to be sure that the calculation is stable for real world values |
| 1323 | * and it is certain that it becomes unstable where the end points are close |
| 1324 | * together. |
| 1325 | * |
| 1326 | * So this code uses the perhaps slightly less optimal but more |
| 1327 | * understandable and totally obvious approach of calculating color-scale. |
| 1328 | * |
| 1329 | * This algorithm depends on the precision in white-scale and that is |
| 1330 | * (1/white-y), so we can immediately see that as white-y approaches 0 the |
| 1331 | * accuracy inherent in the cHRM chunk drops off substantially. |
| 1332 | * |
| 1333 | * libpng arithmetic: a simple inversion of the above equations |
| 1334 | * ------------------------------------------------------------ |
| 1335 | * |
| 1336 | * white_scale = 1/white-y |
| 1337 | * white-X = white-x * white-scale |
| 1338 | * white-Y = 1.0 |
| 1339 | * white-Z = (1 - white-x - white-y) * white_scale |
| 1340 | * |
| 1341 | * white-C = red-C + green-C + blue-C |
| 1342 | * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale |
| 1343 | * |
| 1344 | * This gives us three equations in (red-scale,green-scale,blue-scale) where |
| 1345 | * all the coefficients are now known: |
| 1346 | * |
| 1347 | * red-x*red-scale + green-x*green-scale + blue-x*blue-scale |
| 1348 | * = white-x/white-y |
| 1349 | * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1 |
| 1350 | * red-z*red-scale + green-z*green-scale + blue-z*blue-scale |
| 1351 | * = (1 - white-x - white-y)/white-y |
| 1352 | * |
| 1353 | * In the last equation color-z is (1 - color-x - color-y) so we can add all |
| 1354 | * three equations together to get an alternative third: |
| 1355 | * |
| 1356 | * red-scale + green-scale + blue-scale = 1/white-y = white-scale |
| 1357 | * |
| 1358 | * So now we have a Cramer's rule solution where the determinants are just |
| 1359 | * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve |
| 1360 | * multiplication of three coefficients so we can't guarantee to avoid |
| 1361 | * overflow in the libpng fixed point representation. Using Cramer's rule in |
| 1362 | * floating point is probably a good choice here, but it's not an option for |
| 1363 | * fixed point. Instead proceed to simplify the first two equations by |
| 1364 | * eliminating what is likely to be the largest value, blue-scale: |
| 1365 | * |
| 1366 | * blue-scale = white-scale - red-scale - green-scale |
| 1367 | * |
| 1368 | * Hence: |
| 1369 | * |
| 1370 | * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale = |
| 1371 | * (white-x - blue-x)*white-scale |
| 1372 | * |
| 1373 | * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale = |
| 1374 | * 1 - blue-y*white-scale |
| 1375 | * |
| 1376 | * And now we can trivially solve for (red-scale,green-scale): |
| 1377 | * |
| 1378 | * green-scale = |
| 1379 | * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale |
| 1380 | * ----------------------------------------------------------- |
| 1381 | * green-x - blue-x |
| 1382 | * |
| 1383 | * red-scale = |
| 1384 | * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale |
| 1385 | * --------------------------------------------------------- |
| 1386 | * red-y - blue-y |
| 1387 | * |
| 1388 | * Hence: |
| 1389 | * |
| 1390 | * red-scale = |
| 1391 | * ( (green-x - blue-x) * (white-y - blue-y) - |
| 1392 | * (green-y - blue-y) * (white-x - blue-x) ) / white-y |
| 1393 | * ------------------------------------------------------------------------- |
| 1394 | * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x) |
| 1395 | * |
| 1396 | * green-scale = |
| 1397 | * ( (red-y - blue-y) * (white-x - blue-x) - |
| 1398 | * (red-x - blue-x) * (white-y - blue-y) ) / white-y |
| 1399 | * ------------------------------------------------------------------------- |
| 1400 | * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x) |
| 1401 | * |
| 1402 | * Accuracy: |
| 1403 | * The input values have 5 decimal digits of accuracy. The values are all in |
| 1404 | * the range 0 < value < 1, so simple products are in the same range but may |
| 1405 | * need up to 10 decimal digits to preserve the original precision and avoid |
| 1406 | * underflow. Because we are using a 32-bit signed representation we cannot |
| 1407 | * match this; the best is a little over 9 decimal digits, less than 10. |
| 1408 | * |
| 1409 | * The approach used here is to preserve the maximum precision within the |
| 1410 | * signed representation. Because the red-scale calculation above uses the |
| 1411 | * difference between two products of values that must be in the range -1..+1 |
| 1412 | * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The |
| 1413 | * factor is irrelevant in the calculation because it is applied to both |
| 1414 | * numerator and denominator. |
| 1415 | * |
| 1416 | * Note that the values of the differences of the products of the |
| 1417 | * chromaticities in the above equations tend to be small, for example for |
| 1418 | * the sRGB chromaticities they are: |
| 1419 | * |
| 1420 | * red numerator: -0.04751 |
| 1421 | * green numerator: -0.08788 |
| 1422 | * denominator: -0.2241 (without white-y multiplication) |
| 1423 | * |
| 1424 | * The resultant Y coefficients from the chromaticities of some widely used |
| 1425 | * color space definitions are (to 15 decimal places): |
| 1426 | * |
| 1427 | * sRGB |
| 1428 | * 0.212639005871510 0.715168678767756 0.072192315360734 |
| 1429 | * Kodak ProPhoto |
| 1430 | * 0.288071128229293 0.711843217810102 0.000085653960605 |
| 1431 | * Adobe RGB |
| 1432 | * 0.297344975250536 0.627363566255466 0.075291458493998 |
| 1433 | * Adobe Wide Gamut RGB |
| 1434 | * 0.258728243040113 0.724682314948566 0.016589442011321 |
| 1435 | */ |
| 1436 | /* By the argument, above overflow should be impossible here. The return |
| 1437 | * value of 2 indicates an internal error to the caller. |
| 1438 | */ |
| 1439 | if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0) |
| 1440 | return 2; |
| 1441 | if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0) |
| 1442 | return 2; |
| 1443 | denominator = left - right; |
| 1444 | |
| 1445 | /* Now find the red numerator. */ |
| 1446 | if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0) |
| 1447 | return 2; |
| 1448 | if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0) |
| 1449 | return 2; |
| 1450 | |
| 1451 | /* Overflow is possible here and it indicates an extreme set of PNG cHRM |
| 1452 | * chunk values. This calculation actually returns the reciprocal of the |
| 1453 | * scale value because this allows us to delay the multiplication of white-y |
| 1454 | * into the denominator, which tends to produce a small number. |
| 1455 | */ |
| 1456 | if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 || |
| 1457 | red_inverse <= xy->whitey /* r+g+b scales = white scale */) |
| 1458 | return 1; |
| 1459 | |
| 1460 | /* Similarly for green_inverse: */ |
| 1461 | if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0) |
| 1462 | return 2; |
| 1463 | if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0) |
| 1464 | return 2; |
| 1465 | if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 || |
| 1466 | green_inverse <= xy->whitey) |
| 1467 | return 1; |
| 1468 | |
| 1469 | /* And the blue scale, the checks above guarantee this can't overflow but it |
| 1470 | * can still produce 0 for extreme cHRM values. |
| 1471 | */ |
| 1472 | blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) - |
| 1473 | png_reciprocal(green_inverse); |
| 1474 | if (blue_scale <= 0) |
| 1475 | return 1; |
| 1476 | |
| 1477 | |
| 1478 | /* And fill in the png_XYZ: */ |
| 1479 | if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0) |
| 1480 | return 1; |
| 1481 | if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0) |
| 1482 | return 1; |
| 1483 | if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1, |
| 1484 | red_inverse) == 0) |
| 1485 | return 1; |
| 1486 | |
| 1487 | if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0) |
| 1488 | return 1; |
| 1489 | if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0) |
| 1490 | return 1; |
| 1491 | if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1, |
| 1492 | green_inverse) == 0) |
| 1493 | return 1; |
| 1494 | |
| 1495 | if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0) |
| 1496 | return 1; |
| 1497 | if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0) |
| 1498 | return 1; |
| 1499 | if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale, |
| 1500 | PNG_FP_1) == 0) |
| 1501 | return 1; |
| 1502 | |
| 1503 | return 0; /*success*/ |
| 1504 | } |
| 1505 | |
| 1506 | static int |
| 1507 | png_XYZ_normalize(png_XYZ *XYZ) |
| 1508 | { |
| 1509 | png_int_32 Y; |
| 1510 | |
| 1511 | if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 || |
| 1512 | XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 || |
| 1513 | XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0) |
| 1514 | return 1; |
| 1515 | |
| 1516 | /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1. |
| 1517 | * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore |
| 1518 | * relying on addition of two positive values producing a negative one is not |
| 1519 | * safe. |
| 1520 | */ |
| 1521 | Y = XYZ->red_Y; |
| 1522 | if (0x7fffffff - Y < XYZ->green_X) |
| 1523 | return 1; |
| 1524 | Y += XYZ->green_Y; |
| 1525 | if (0x7fffffff - Y < XYZ->blue_X) |
| 1526 | return 1; |
| 1527 | Y += XYZ->blue_Y; |
| 1528 | |
| 1529 | if (Y != PNG_FP_1) |
| 1530 | { |
| 1531 | if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0) |
| 1532 | return 1; |
| 1533 | if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0) |
| 1534 | return 1; |
| 1535 | if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0) |
| 1536 | return 1; |
| 1537 | |
| 1538 | if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0) |
| 1539 | return 1; |
| 1540 | if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0) |
| 1541 | return 1; |
| 1542 | if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0) |
| 1543 | return 1; |
| 1544 | |
| 1545 | if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0) |
| 1546 | return 1; |
| 1547 | if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0) |
| 1548 | return 1; |
| 1549 | if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0) |
| 1550 | return 1; |
| 1551 | } |
| 1552 | |
| 1553 | return 0; |
| 1554 | } |
| 1555 | |
| 1556 | static int |
| 1557 | png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta) |
| 1558 | { |
| 1559 | /* Allow an error of +/-0.01 (absolute value) on each chromaticity */ |
| 1560 | if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) || |
| 1561 | PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) || |
| 1562 | PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) || |
| 1563 | PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) || |
| 1564 | PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) || |
| 1565 | PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) || |
| 1566 | PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) || |
| 1567 | PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta)) |
| 1568 | return 0; |
| 1569 | return 1; |
| 1570 | } |
| 1571 | |
| 1572 | /* Added in libpng-1.6.0, a different check for the validity of a set of cHRM |
| 1573 | * chunk chromaticities. Earlier checks used to simply look for the overflow |
| 1574 | * condition (where the determinant of the matrix to solve for XYZ ends up zero |
| 1575 | * because the chromaticity values are not all distinct.) Despite this it is |
| 1576 | * theoretically possible to produce chromaticities that are apparently valid |
| 1577 | * but that rapidly degrade to invalid, potentially crashing, sets because of |
| 1578 | * arithmetic inaccuracies when calculations are performed on them. The new |
| 1579 | * check is to round-trip xy -> XYZ -> xy and then check that the result is |
| 1580 | * within a small percentage of the original. |
| 1581 | */ |
| 1582 | static int |
| 1583 | png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy) |
| 1584 | { |
| 1585 | int result; |
| 1586 | png_xy xy_test; |
| 1587 | |
| 1588 | /* As a side-effect this routine also returns the XYZ endpoints. */ |
| 1589 | result = png_XYZ_from_xy(XYZ, xy); |
| 1590 | if (result != 0) |
| 1591 | return result; |
| 1592 | |
| 1593 | result = png_xy_from_XYZ(&xy_test, XYZ); |
| 1594 | if (result != 0) |
| 1595 | return result; |
| 1596 | |
| 1597 | if (png_colorspace_endpoints_match(xy, &xy_test, |
| 1598 | 5/*actually, the math is pretty accurate*/) != 0) |
| 1599 | return 0; |
| 1600 | |
| 1601 | /* Too much slip */ |
| 1602 | return 1; |
| 1603 | } |
| 1604 | |
| 1605 | /* This is the check going the other way. The XYZ is modified to normalize it |
| 1606 | * (another side-effect) and the xy chromaticities are returned. |
| 1607 | */ |
| 1608 | static int |
| 1609 | png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ) |
| 1610 | { |
| 1611 | int result; |
| 1612 | png_XYZ XYZtemp; |
| 1613 | |
| 1614 | result = png_XYZ_normalize(XYZ); |
| 1615 | if (result != 0) |
| 1616 | return result; |
| 1617 | |
| 1618 | result = png_xy_from_XYZ(xy, XYZ); |
| 1619 | if (result != 0) |
| 1620 | return result; |
| 1621 | |
| 1622 | XYZtemp = *XYZ; |
| 1623 | return png_colorspace_check_xy(&XYZtemp, xy); |
| 1624 | } |
| 1625 | |
| 1626 | /* Used to check for an endpoint match against sRGB */ |
| 1627 | static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */ |
| 1628 | { |
| 1629 | /* color x y */ |
| 1630 | /* red */ 64000, 33000, |
| 1631 | /* green */ 30000, 60000, |
| 1632 | /* blue */ 15000, 6000, |
| 1633 | /* white */ 31270, 32900 |
| 1634 | }; |
| 1635 | |
| 1636 | static int |
| 1637 | png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr, |
| 1638 | png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ, |
| 1639 | int preferred) |
| 1640 | { |
| 1641 | if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0) |
| 1642 | return 0; |
| 1643 | |
| 1644 | /* The consistency check is performed on the chromaticities; this factors out |
| 1645 | * variations because of the normalization (or not) of the end point Y |
| 1646 | * values. |
| 1647 | */ |
| 1648 | if (preferred < 2 && |
| 1649 | (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0) |
| 1650 | { |
| 1651 | /* The end points must be reasonably close to any we already have. The |
| 1652 | * following allows an error of up to +/-.001 |
| 1653 | */ |
| 1654 | if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy, |
| 1655 | 100) == 0) |
| 1656 | { |
| 1657 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1658 | png_benign_error(png_ptr, "inconsistent chromaticities"); |
| 1659 | return 0; /* failed */ |
| 1660 | } |
| 1661 | |
| 1662 | /* Only overwrite with preferred values */ |
| 1663 | if (preferred == 0) |
| 1664 | return 1; /* ok, but no change */ |
| 1665 | } |
| 1666 | |
| 1667 | colorspace->end_points_xy = *xy; |
| 1668 | colorspace->end_points_XYZ = *XYZ; |
| 1669 | colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS; |
| 1670 | |
| 1671 | /* The end points are normally quoted to two decimal digits, so allow +/-0.01 |
| 1672 | * on this test. |
| 1673 | */ |
| 1674 | if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0) |
| 1675 | colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB; |
| 1676 | |
| 1677 | else |
| 1678 | colorspace->flags &= PNG_COLORSPACE_CANCEL( |
| 1679 | PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); |
| 1680 | |
| 1681 | return 2; /* ok and changed */ |
| 1682 | } |
| 1683 | |
| 1684 | int /* PRIVATE */ |
| 1685 | png_colorspace_set_chromaticities(png_const_structrp png_ptr, |
| 1686 | png_colorspacerp colorspace, const png_xy *xy, int preferred) |
| 1687 | { |
| 1688 | /* We must check the end points to ensure they are reasonable - in the past |
| 1689 | * color management systems have crashed as a result of getting bogus |
| 1690 | * colorant values, while this isn't the fault of libpng it is the |
| 1691 | * responsibility of libpng because PNG carries the bomb and libpng is in a |
| 1692 | * position to protect against it. |
| 1693 | */ |
| 1694 | png_XYZ XYZ; |
| 1695 | |
| 1696 | switch (png_colorspace_check_xy(&XYZ, xy)) |
| 1697 | { |
| 1698 | case 0: /* success */ |
| 1699 | return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ, |
| 1700 | preferred); |
| 1701 | |
| 1702 | case 1: |
| 1703 | /* We can't invert the chromaticities so we can't produce value XYZ |
| 1704 | * values. Likely as not a color management system will fail too. |
| 1705 | */ |
| 1706 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1707 | png_benign_error(png_ptr, "invalid chromaticities"); |
| 1708 | break; |
| 1709 | |
| 1710 | default: |
| 1711 | /* libpng is broken; this should be a warning but if it happens we |
| 1712 | * want error reports so for the moment it is an error. |
| 1713 | */ |
| 1714 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1715 | png_error(png_ptr, "internal error checking chromaticities"); |
| 1716 | } |
| 1717 | |
| 1718 | return 0; /* failed */ |
| 1719 | } |
| 1720 | |
| 1721 | int /* PRIVATE */ |
| 1722 | png_colorspace_set_endpoints(png_const_structrp png_ptr, |
| 1723 | png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred) |
| 1724 | { |
| 1725 | png_XYZ XYZ = *XYZ_in; |
| 1726 | png_xy xy; |
| 1727 | |
| 1728 | switch (png_colorspace_check_XYZ(&xy, &XYZ)) |
| 1729 | { |
| 1730 | case 0: |
| 1731 | return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ, |
| 1732 | preferred); |
| 1733 | |
| 1734 | case 1: |
| 1735 | /* End points are invalid. */ |
| 1736 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1737 | png_benign_error(png_ptr, "invalid end points"); |
| 1738 | break; |
| 1739 | |
| 1740 | default: |
| 1741 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1742 | png_error(png_ptr, "internal error checking chromaticities"); |
| 1743 | } |
| 1744 | |
| 1745 | return 0; /* failed */ |
| 1746 | } |
| 1747 | |
| 1748 | #if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED) |
| 1749 | /* Error message generation */ |
| 1750 | static char |
| 1751 | png_icc_tag_char(png_uint_32 byte) |
| 1752 | { |
| 1753 | byte &= 0xff; |
| 1754 | if (byte >= 32 && byte <= 126) |
| 1755 | return (char)byte; |
| 1756 | else |
| 1757 | return '?'; |
| 1758 | } |
| 1759 | |
| 1760 | static void |
| 1761 | png_icc_tag_name(char *name, png_uint_32 tag) |
| 1762 | { |
| 1763 | name[0] = '\''; |
| 1764 | name[1] = png_icc_tag_char(tag >> 24); |
| 1765 | name[2] = png_icc_tag_char(tag >> 16); |
| 1766 | name[3] = png_icc_tag_char(tag >> 8); |
| 1767 | name[4] = png_icc_tag_char(tag ); |
| 1768 | name[5] = '\''; |
| 1769 | } |
| 1770 | |
| 1771 | static int |
| 1772 | is_ICC_signature_char(png_alloc_size_t it) |
| 1773 | { |
| 1774 | return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) || |
| 1775 | (it >= 97 && it <= 122); |
| 1776 | } |
| 1777 | |
| 1778 | static int |
| 1779 | is_ICC_signature(png_alloc_size_t it) |
| 1780 | { |
| 1781 | return is_ICC_signature_char(it >> 24) /* checks all the top bits */ && |
| 1782 | is_ICC_signature_char((it >> 16) & 0xff) && |
| 1783 | is_ICC_signature_char((it >> 8) & 0xff) && |
| 1784 | is_ICC_signature_char(it & 0xff); |
| 1785 | } |
| 1786 | |
| 1787 | static int |
| 1788 | png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace, |
| 1789 | png_const_charp name, png_alloc_size_t value, png_const_charp reason) |
| 1790 | { |
| 1791 | size_t pos; |
| 1792 | char message[196]; /* see below for calculation */ |
| 1793 | |
| 1794 | if (colorspace != NULL) |
| 1795 | colorspace->flags |= PNG_COLORSPACE_INVALID; |
| 1796 | |
| 1797 | pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */ |
| 1798 | pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */ |
| 1799 | pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */ |
| 1800 | if (is_ICC_signature(value) != 0) |
| 1801 | { |
| 1802 | /* So 'value' is at most 4 bytes and the following cast is safe */ |
| 1803 | png_icc_tag_name(message+pos, (png_uint_32)value); |
| 1804 | pos += 6; /* total +8; less than the else clause */ |
| 1805 | message[pos++] = ':'; |
| 1806 | message[pos++] = ' '; |
| 1807 | } |
| 1808 | # ifdef PNG_WARNINGS_SUPPORTED |
| 1809 | else |
| 1810 | { |
| 1811 | char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/ |
| 1812 | |
| 1813 | pos = png_safecat(message, (sizeof message), pos, |
| 1814 | png_format_number(number, number+(sizeof number), |
| 1815 | PNG_NUMBER_FORMAT_x, value)); |
| 1816 | pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/ |
| 1817 | } |
| 1818 | # endif |
| 1819 | /* The 'reason' is an arbitrary message, allow +79 maximum 195 */ |
| 1820 | pos = png_safecat(message, (sizeof message), pos, reason); |
| 1821 | PNG_UNUSED(pos) |
| 1822 | |
| 1823 | /* This is recoverable, but make it unconditionally an app_error on write to |
| 1824 | * avoid writing invalid ICC profiles into PNG files (i.e., we handle them |
| 1825 | * on read, with a warning, but on write unless the app turns off |
| 1826 | * application errors the PNG won't be written.) |
| 1827 | */ |
| 1828 | png_chunk_report(png_ptr, message, |
| 1829 | (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR); |
| 1830 | |
| 1831 | return 0; |
| 1832 | } |
| 1833 | #endif /* sRGB || iCCP */ |
| 1834 | |
| 1835 | #ifdef PNG_sRGB_SUPPORTED |
| 1836 | int /* PRIVATE */ |
| 1837 | png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace, |
| 1838 | int intent) |
| 1839 | { |
| 1840 | /* sRGB sets known gamma, end points and (from the chunk) intent. */ |
| 1841 | /* IMPORTANT: these are not necessarily the values found in an ICC profile |
| 1842 | * because ICC profiles store values adapted to a D50 environment; it is |
| 1843 | * expected that the ICC profile mediaWhitePointTag will be D50; see the |
| 1844 | * checks and code elsewhere to understand this better. |
| 1845 | * |
| 1846 | * These XYZ values, which are accurate to 5dp, produce rgb to gray |
| 1847 | * coefficients of (6968,23435,2366), which are reduced (because they add up |
| 1848 | * to 32769 not 32768) to (6968,23434,2366). These are the values that |
| 1849 | * libpng has traditionally used (and are the best values given the 15bit |
| 1850 | * algorithm used by the rgb to gray code.) |
| 1851 | */ |
| 1852 | static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */ |
| 1853 | { |
| 1854 | /* color X Y Z */ |
| 1855 | /* red */ 41239, 21264, 1933, |
| 1856 | /* green */ 35758, 71517, 11919, |
| 1857 | /* blue */ 18048, 7219, 95053 |
| 1858 | }; |
| 1859 | |
| 1860 | /* Do nothing if the colorspace is already invalidated. */ |
| 1861 | if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0) |
| 1862 | return 0; |
| 1863 | |
| 1864 | /* Check the intent, then check for existing settings. It is valid for the |
| 1865 | * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must |
| 1866 | * be consistent with the correct values. If, however, this function is |
| 1867 | * called below because an iCCP chunk matches sRGB then it is quite |
| 1868 | * conceivable that an older app recorded incorrect gAMA and cHRM because of |
| 1869 | * an incorrect calculation based on the values in the profile - this does |
| 1870 | * *not* invalidate the profile (though it still produces an error, which can |
| 1871 | * be ignored.) |
| 1872 | */ |
| 1873 | if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST) |
| 1874 | return png_icc_profile_error(png_ptr, colorspace, "sRGB", |
| 1875 | (unsigned)intent, "invalid sRGB rendering intent"); |
| 1876 | |
| 1877 | if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 && |
| 1878 | colorspace->rendering_intent != intent) |
| 1879 | return png_icc_profile_error(png_ptr, colorspace, "sRGB", |
| 1880 | (unsigned)intent, "inconsistent rendering intents"); |
| 1881 | |
| 1882 | if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0) |
| 1883 | { |
| 1884 | png_benign_error(png_ptr, "duplicate sRGB information ignored"); |
| 1885 | return 0; |
| 1886 | } |
| 1887 | |
| 1888 | /* If the standard sRGB cHRM chunk does not match the one from the PNG file |
| 1889 | * warn but overwrite the value with the correct one. |
| 1890 | */ |
| 1891 | if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 && |
| 1892 | !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy, |
| 1893 | 100)) |
| 1894 | png_chunk_report(png_ptr, "cHRM chunk does not match sRGB", |
| 1895 | PNG_CHUNK_ERROR); |
| 1896 | |
| 1897 | /* This check is just done for the error reporting - the routine always |
| 1898 | * returns true when the 'from' argument corresponds to sRGB (2). |
| 1899 | */ |
| 1900 | (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE, |
| 1901 | 2/*from sRGB*/); |
| 1902 | |
| 1903 | /* intent: bugs in GCC force 'int' to be used as the parameter type. */ |
| 1904 | colorspace->rendering_intent = (png_uint_16)intent; |
| 1905 | colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT; |
| 1906 | |
| 1907 | /* endpoints */ |
| 1908 | colorspace->end_points_xy = sRGB_xy; |
| 1909 | colorspace->end_points_XYZ = sRGB_XYZ; |
| 1910 | colorspace->flags |= |
| 1911 | (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); |
| 1912 | |
| 1913 | /* gamma */ |
| 1914 | colorspace->gamma = PNG_GAMMA_sRGB_INVERSE; |
| 1915 | colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA; |
| 1916 | |
| 1917 | /* Finally record that we have an sRGB profile */ |
| 1918 | colorspace->flags |= |
| 1919 | (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB); |
| 1920 | |
| 1921 | return 1; /* set */ |
| 1922 | } |
| 1923 | #endif /* sRGB */ |
| 1924 | |
| 1925 | #ifdef PNG_iCCP_SUPPORTED |
| 1926 | /* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value |
| 1927 | * is XYZ(0.9642,1.0,0.8249), which scales to: |
| 1928 | * |
| 1929 | * (63189.8112, 65536, 54060.6464) |
| 1930 | */ |
| 1931 | static const png_byte D50_nCIEXYZ[12] = |
| 1932 | { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d }; |
| 1933 | |
| 1934 | int /* PRIVATE */ |
| 1935 | png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace, |
| 1936 | png_const_charp name, png_uint_32 profile_length) |
| 1937 | { |
| 1938 | if (profile_length < 132) |
| 1939 | return png_icc_profile_error(png_ptr, colorspace, name, profile_length, |
| 1940 | "too short"); |
| 1941 | |
| 1942 | return 1; |
| 1943 | } |
| 1944 | |
| 1945 | int /* PRIVATE */ |
| 1946 | png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace, |
| 1947 | png_const_charp name, png_uint_32 profile_length, |
| 1948 | png_const_bytep profile/* first 132 bytes only */, int color_type) |
| 1949 | { |
| 1950 | png_uint_32 temp; |
| 1951 | |
| 1952 | /* Length check; this cannot be ignored in this code because profile_length |
| 1953 | * is used later to check the tag table, so even if the profile seems over |
| 1954 | * long profile_length from the caller must be correct. The caller can fix |
| 1955 | * this up on read or write by just passing in the profile header length. |
| 1956 | */ |
| 1957 | temp = png_get_uint_32(profile); |
| 1958 | if (temp != profile_length) |
| 1959 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 1960 | "length does not match profile"); |
| 1961 | |
| 1962 | temp = (png_uint_32) (*(profile+8)); |
| 1963 | if (temp > 3 && (profile_length & 3)) |
| 1964 | return png_icc_profile_error(png_ptr, colorspace, name, profile_length, |
| 1965 | "invalid length"); |
| 1966 | |
| 1967 | temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */ |
| 1968 | if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */ |
| 1969 | profile_length < 132+12*temp) /* truncated tag table */ |
| 1970 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 1971 | "tag count too large"); |
| 1972 | |
| 1973 | /* The 'intent' must be valid or we can't store it, ICC limits the intent to |
| 1974 | * 16 bits. |
| 1975 | */ |
| 1976 | temp = png_get_uint_32(profile+64); |
| 1977 | if (temp >= 0xffff) /* The ICC limit */ |
| 1978 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 1979 | "invalid rendering intent"); |
| 1980 | |
| 1981 | /* This is just a warning because the profile may be valid in future |
| 1982 | * versions. |
| 1983 | */ |
| 1984 | if (temp >= PNG_sRGB_INTENT_LAST) |
| 1985 | (void)png_icc_profile_error(png_ptr, NULL, name, temp, |
| 1986 | "intent outside defined range"); |
| 1987 | |
| 1988 | /* At this point the tag table can't be checked because it hasn't necessarily |
| 1989 | * been loaded; however, various header fields can be checked. These checks |
| 1990 | * are for values permitted by the PNG spec in an ICC profile; the PNG spec |
| 1991 | * restricts the profiles that can be passed in an iCCP chunk (they must be |
| 1992 | * appropriate to processing PNG data!) |
| 1993 | */ |
| 1994 | |
| 1995 | /* Data checks (could be skipped). These checks must be independent of the |
| 1996 | * version number; however, the version number doesn't accomodate changes in |
| 1997 | * the header fields (just the known tags and the interpretation of the |
| 1998 | * data.) |
| 1999 | */ |
| 2000 | temp = png_get_uint_32(profile+36); /* signature 'ascp' */ |
| 2001 | if (temp != 0x61637370) |
| 2002 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2003 | "invalid signature"); |
| 2004 | |
| 2005 | /* Currently the PCS illuminant/adopted white point (the computational |
| 2006 | * white point) are required to be D50, |
| 2007 | * however the profile contains a record of the illuminant so perhaps ICC |
| 2008 | * expects to be able to change this in the future (despite the rationale in |
| 2009 | * the introduction for using a fixed PCS adopted white.) Consequently the |
| 2010 | * following is just a warning. |
| 2011 | */ |
| 2012 | if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0) |
| 2013 | (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/, |
| 2014 | "PCS illuminant is not D50"); |
| 2015 | |
| 2016 | /* The PNG spec requires this: |
| 2017 | * "If the iCCP chunk is present, the image samples conform to the colour |
| 2018 | * space represented by the embedded ICC profile as defined by the |
| 2019 | * International Color Consortium [ICC]. The colour space of the ICC profile |
| 2020 | * shall be an RGB colour space for colour images (PNG colour types 2, 3, and |
| 2021 | * 6), or a greyscale colour space for greyscale images (PNG colour types 0 |
| 2022 | * and 4)." |
| 2023 | * |
| 2024 | * This checking code ensures the embedded profile (on either read or write) |
| 2025 | * conforms to the specification requirements. Notice that an ICC 'gray' |
| 2026 | * color-space profile contains the information to transform the monochrome |
| 2027 | * data to XYZ or L*a*b (according to which PCS the profile uses) and this |
| 2028 | * should be used in preference to the standard libpng K channel replication |
| 2029 | * into R, G and B channels. |
| 2030 | * |
| 2031 | * Previously it was suggested that an RGB profile on grayscale data could be |
| 2032 | * handled. However it it is clear that using an RGB profile in this context |
| 2033 | * must be an error - there is no specification of what it means. Thus it is |
| 2034 | * almost certainly more correct to ignore the profile. |
| 2035 | */ |
| 2036 | temp = png_get_uint_32(profile+16); /* data colour space field */ |
| 2037 | switch (temp) |
| 2038 | { |
| 2039 | case 0x52474220: /* 'RGB ' */ |
| 2040 | if ((color_type & PNG_COLOR_MASK_COLOR) == 0) |
| 2041 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2042 | "RGB color space not permitted on grayscale PNG"); |
| 2043 | break; |
| 2044 | |
| 2045 | case 0x47524159: /* 'GRAY' */ |
| 2046 | if ((color_type & PNG_COLOR_MASK_COLOR) != 0) |
| 2047 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2048 | "Gray color space not permitted on RGB PNG"); |
| 2049 | break; |
| 2050 | |
| 2051 | default: |
| 2052 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2053 | "invalid ICC profile color space"); |
| 2054 | } |
| 2055 | |
| 2056 | /* It is up to the application to check that the profile class matches the |
| 2057 | * application requirements; the spec provides no guidance, but it's pretty |
| 2058 | * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer |
| 2059 | * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these |
| 2060 | * cases. Issue an error for device link or abstract profiles - these don't |
| 2061 | * contain the records necessary to transform the color-space to anything |
| 2062 | * other than the target device (and not even that for an abstract profile). |
| 2063 | * Profiles of these classes may not be embedded in images. |
| 2064 | */ |
| 2065 | temp = png_get_uint_32(profile+12); /* profile/device class */ |
| 2066 | switch (temp) |
| 2067 | { |
| 2068 | case 0x73636e72: /* 'scnr' */ |
| 2069 | case 0x6d6e7472: /* 'mntr' */ |
| 2070 | case 0x70727472: /* 'prtr' */ |
| 2071 | case 0x73706163: /* 'spac' */ |
| 2072 | /* All supported */ |
| 2073 | break; |
| 2074 | |
| 2075 | case 0x61627374: /* 'abst' */ |
| 2076 | /* May not be embedded in an image */ |
| 2077 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2078 | "invalid embedded Abstract ICC profile"); |
| 2079 | |
| 2080 | case 0x6c696e6b: /* 'link' */ |
| 2081 | /* DeviceLink profiles cannot be interpreted in a non-device specific |
| 2082 | * fashion, if an app uses the AToB0Tag in the profile the results are |
| 2083 | * undefined unless the result is sent to the intended device, |
| 2084 | * therefore a DeviceLink profile should not be found embedded in a |
| 2085 | * PNG. |
| 2086 | */ |
| 2087 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2088 | "unexpected DeviceLink ICC profile class"); |
| 2089 | |
| 2090 | case 0x6e6d636c: /* 'nmcl' */ |
| 2091 | /* A NamedColor profile is also device specific, however it doesn't |
| 2092 | * contain an AToB0 tag that is open to misinterpretation. Almost |
| 2093 | * certainly it will fail the tests below. |
| 2094 | */ |
| 2095 | (void)png_icc_profile_error(png_ptr, NULL, name, temp, |
| 2096 | "unexpected NamedColor ICC profile class"); |
| 2097 | break; |
| 2098 | |
| 2099 | default: |
| 2100 | /* To allow for future enhancements to the profile accept unrecognized |
| 2101 | * profile classes with a warning, these then hit the test below on the |
| 2102 | * tag content to ensure they are backward compatible with one of the |
| 2103 | * understood profiles. |
| 2104 | */ |
| 2105 | (void)png_icc_profile_error(png_ptr, NULL, name, temp, |
| 2106 | "unrecognized ICC profile class"); |
| 2107 | break; |
| 2108 | } |
| 2109 | |
| 2110 | /* For any profile other than a device link one the PCS must be encoded |
| 2111 | * either in XYZ or Lab. |
| 2112 | */ |
| 2113 | temp = png_get_uint_32(profile+20); |
| 2114 | switch (temp) |
| 2115 | { |
| 2116 | case 0x58595a20: /* 'XYZ ' */ |
| 2117 | case 0x4c616220: /* 'Lab ' */ |
| 2118 | break; |
| 2119 | |
| 2120 | default: |
| 2121 | return png_icc_profile_error(png_ptr, colorspace, name, temp, |
| 2122 | "unexpected ICC PCS encoding"); |
| 2123 | } |
| 2124 | |
| 2125 | return 1; |
| 2126 | } |
| 2127 | |
| 2128 | int /* PRIVATE */ |
| 2129 | png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace, |
| 2130 | png_const_charp name, png_uint_32 profile_length, |
| 2131 | png_const_bytep profile /* header plus whole tag table */) |
| 2132 | { |
| 2133 | png_uint_32 tag_count = png_get_uint_32(profile+128); |
| 2134 | png_uint_32 itag; |
| 2135 | png_const_bytep tag = profile+132; /* The first tag */ |
| 2136 | |
| 2137 | /* First scan all the tags in the table and add bits to the icc_info value |
| 2138 | * (temporarily in 'tags'). |
| 2139 | */ |
| 2140 | for (itag=0; itag < tag_count; ++itag, tag += 12) |
| 2141 | { |
| 2142 | png_uint_32 tag_id = png_get_uint_32(tag+0); |
| 2143 | png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */ |
| 2144 | png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */ |
| 2145 | |
| 2146 | /* The ICC specification does not exclude zero length tags, therefore the |
| 2147 | * start might actually be anywhere if there is no data, but this would be |
| 2148 | * a clear abuse of the intent of the standard so the start is checked for |
| 2149 | * being in range. All defined tag types have an 8 byte header - a 4 byte |
| 2150 | * type signature then 0. |
| 2151 | */ |
| 2152 | if ((tag_start & 3) != 0) |
| 2153 | { |
| 2154 | /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is |
| 2155 | * only a warning here because libpng does not care about the |
| 2156 | * alignment. |
| 2157 | */ |
| 2158 | (void)png_icc_profile_error(png_ptr, NULL, name, tag_id, |
| 2159 | "ICC profile tag start not a multiple of 4"); |
| 2160 | } |
| 2161 | |
| 2162 | /* This is a hard error; potentially it can cause read outside the |
| 2163 | * profile. |
| 2164 | */ |
| 2165 | if (tag_start > profile_length || tag_length > profile_length - tag_start) |
| 2166 | return png_icc_profile_error(png_ptr, colorspace, name, tag_id, |
| 2167 | "ICC profile tag outside profile"); |
| 2168 | } |
| 2169 | |
| 2170 | return 1; /* success, maybe with warnings */ |
| 2171 | } |
| 2172 | |
| 2173 | #ifdef PNG_sRGB_SUPPORTED |
| 2174 | #if PNG_sRGB_PROFILE_CHECKS >= 0 |
| 2175 | /* Information about the known ICC sRGB profiles */ |
| 2176 | static const struct |
| 2177 | { |
| 2178 | png_uint_32 adler, crc, length; |
| 2179 | png_uint_32 md5[4]; |
| 2180 | png_byte have_md5; |
| 2181 | png_byte is_broken; |
| 2182 | png_uint_16 intent; |
| 2183 | |
| 2184 | # define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0) |
| 2185 | # define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\ |
| 2186 | { adler, crc, length, md5, broke, intent }, |
| 2187 | |
| 2188 | } png_sRGB_checks[] = |
| 2189 | { |
| 2190 | /* This data comes from contrib/tools/checksum-icc run on downloads of |
| 2191 | * all four ICC sRGB profiles from www.color.org. |
| 2192 | */ |
| 2193 | /* adler32, crc32, MD5[4], intent, date, length, file-name */ |
| 2194 | PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9, |
| 2195 | PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0, |
| 2196 | "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc") |
| 2197 | |
| 2198 | /* ICC sRGB v2 perceptual no black-compensation: */ |
| 2199 | PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21, |
| 2200 | PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0, |
| 2201 | "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc") |
| 2202 | |
| 2203 | PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae, |
| 2204 | PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0, |
| 2205 | "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc") |
| 2206 | |
| 2207 | /* ICC sRGB v4 perceptual */ |
| 2208 | PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812, |
| 2209 | PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0, |
| 2210 | "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc") |
| 2211 | |
| 2212 | /* The following profiles have no known MD5 checksum. If there is a match |
| 2213 | * on the (empty) MD5 the other fields are used to attempt a match and |
| 2214 | * a warning is produced. The first two of these profiles have a 'cprt' tag |
| 2215 | * which suggests that they were also made by Hewlett Packard. |
| 2216 | */ |
| 2217 | PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce, |
| 2218 | PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0, |
| 2219 | "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc") |
| 2220 | |
| 2221 | /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not |
| 2222 | * match the D50 PCS illuminant in the header (it is in fact the D65 values, |
| 2223 | * so the white point is recorded as the un-adapted value.) The profiles |
| 2224 | * below only differ in one byte - the intent - and are basically the same as |
| 2225 | * the previous profile except for the mediaWhitePointTag error and a missing |
| 2226 | * chromaticAdaptationTag. |
| 2227 | */ |
| 2228 | PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552, |
| 2229 | PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/, |
| 2230 | "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual") |
| 2231 | |
| 2232 | PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d, |
| 2233 | PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/, |
| 2234 | "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative") |
| 2235 | }; |
| 2236 | |
| 2237 | static int |
| 2238 | png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr, |
| 2239 | png_const_bytep profile, uLong adler) |
| 2240 | { |
| 2241 | /* The quick check is to verify just the MD5 signature and trust the |
| 2242 | * rest of the data. Because the profile has already been verified for |
| 2243 | * correctness this is safe. png_colorspace_set_sRGB will check the 'intent' |
| 2244 | * field too, so if the profile has been edited with an intent not defined |
| 2245 | * by sRGB (but maybe defined by a later ICC specification) the read of |
| 2246 | * the profile will fail at that point. |
| 2247 | */ |
| 2248 | |
| 2249 | png_uint_32 length = 0; |
| 2250 | png_uint_32 intent = 0x10000; /* invalid */ |
| 2251 | #if PNG_sRGB_PROFILE_CHECKS > 1 |
| 2252 | uLong crc = 0; /* the value for 0 length data */ |
| 2253 | #endif |
| 2254 | unsigned int i; |
| 2255 | |
| 2256 | #ifdef PNG_SET_OPTION_SUPPORTED |
| 2257 | /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */ |
| 2258 | if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) == |
| 2259 | PNG_OPTION_ON) |
| 2260 | return 0; |
| 2261 | #endif |
| 2262 | |
| 2263 | for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i) |
| 2264 | { |
| 2265 | if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] && |
| 2266 | png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] && |
| 2267 | png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] && |
| 2268 | png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3]) |
| 2269 | { |
| 2270 | /* This may be one of the old HP profiles without an MD5, in that |
| 2271 | * case we can only use the length and Adler32 (note that these |
| 2272 | * are not used by default if there is an MD5!) |
| 2273 | */ |
| 2274 | # if PNG_sRGB_PROFILE_CHECKS == 0 |
| 2275 | if (png_sRGB_checks[i].have_md5 != 0) |
| 2276 | return 1+png_sRGB_checks[i].is_broken; |
| 2277 | # endif |
| 2278 | |
| 2279 | /* Profile is unsigned or more checks have been configured in. */ |
| 2280 | if (length == 0) |
| 2281 | { |
| 2282 | length = png_get_uint_32(profile); |
| 2283 | intent = png_get_uint_32(profile+64); |
| 2284 | } |
| 2285 | |
| 2286 | /* Length *and* intent must match */ |
| 2287 | if (length == (png_uint_32) png_sRGB_checks[i].length && |
| 2288 | intent == (png_uint_32) png_sRGB_checks[i].intent) |
| 2289 | { |
| 2290 | /* Now calculate the adler32 if not done already. */ |
| 2291 | if (adler == 0) |
| 2292 | { |
| 2293 | adler = adler32(0, NULL, 0); |
| 2294 | adler = adler32(adler, profile, length); |
| 2295 | } |
| 2296 | |
| 2297 | if (adler == png_sRGB_checks[i].adler) |
| 2298 | { |
| 2299 | /* These basic checks suggest that the data has not been |
| 2300 | * modified, but if the check level is more than 1 perform |
| 2301 | * our own crc32 checksum on the data. |
| 2302 | */ |
| 2303 | # if PNG_sRGB_PROFILE_CHECKS > 1 |
| 2304 | if (crc == 0) |
| 2305 | { |
| 2306 | crc = crc32(0, NULL, 0); |
| 2307 | crc = crc32(crc, profile, length); |
| 2308 | } |
| 2309 | |
| 2310 | /* So this check must pass for the 'return' below to happen. |
| 2311 | */ |
| 2312 | if (crc == png_sRGB_checks[i].crc) |
| 2313 | # endif |
| 2314 | { |
| 2315 | if (png_sRGB_checks[i].is_broken != 0) |
| 2316 | { |
| 2317 | /* These profiles are known to have bad data that may cause |
| 2318 | * problems if they are used, therefore attempt to |
| 2319 | * discourage their use, skip the 'have_md5' warning below, |
| 2320 | * which is made irrelevant by this error. |
| 2321 | */ |
| 2322 | png_chunk_report(png_ptr, "known incorrect sRGB profile", |
| 2323 | PNG_CHUNK_ERROR); |
| 2324 | } |
| 2325 | |
| 2326 | /* Warn that this being done; this isn't even an error since |
| 2327 | * the profile is perfectly valid, but it would be nice if |
| 2328 | * people used the up-to-date ones. |
| 2329 | */ |
| 2330 | else if (png_sRGB_checks[i].have_md5 == 0) |
| 2331 | { |
| 2332 | png_chunk_report(png_ptr, |
| 2333 | "out-of-date sRGB profile with no signature", |
| 2334 | PNG_CHUNK_WARNING); |
| 2335 | } |
| 2336 | |
| 2337 | return 1+png_sRGB_checks[i].is_broken; |
| 2338 | } |
| 2339 | } |
| 2340 | |
| 2341 | # if PNG_sRGB_PROFILE_CHECKS > 0 |
| 2342 | /* The signature matched, but the profile had been changed in some |
| 2343 | * way. This probably indicates a data error or uninformed hacking. |
| 2344 | * Fall through to "no match". |
| 2345 | */ |
| 2346 | png_chunk_report(png_ptr, |
| 2347 | "Not recognizing known sRGB profile that has been edited", |
| 2348 | PNG_CHUNK_WARNING); |
| 2349 | break; |
| 2350 | # endif |
| 2351 | } |
| 2352 | } |
| 2353 | } |
| 2354 | |
| 2355 | return 0; /* no match */ |
| 2356 | } |
| 2357 | #endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */ |
| 2358 | |
| 2359 | void /* PRIVATE */ |
| 2360 | png_icc_set_sRGB(png_const_structrp png_ptr, |
| 2361 | png_colorspacerp colorspace, png_const_bytep profile, uLong adler) |
| 2362 | { |
| 2363 | /* Is this profile one of the known ICC sRGB profiles? If it is, just set |
| 2364 | * the sRGB information. |
| 2365 | */ |
| 2366 | #if PNG_sRGB_PROFILE_CHECKS >= 0 |
| 2367 | if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0) |
| 2368 | #endif |
| 2369 | (void)png_colorspace_set_sRGB(png_ptr, colorspace, |
| 2370 | (int)/*already checked*/png_get_uint_32(profile+64)); |
| 2371 | } |
| 2372 | #endif /* sRGB */ |
| 2373 | |
| 2374 | int /* PRIVATE */ |
| 2375 | png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace, |
| 2376 | png_const_charp name, png_uint_32 profile_length, png_const_bytep profile, |
| 2377 | int color_type) |
| 2378 | { |
| 2379 | if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0) |
| 2380 | return 0; |
| 2381 | |
| 2382 | if (png_icc_check_length(png_ptr, colorspace, name, profile_length) != 0 && |
| 2383 | png_icc_check_header(png_ptr, colorspace, name, profile_length, profile, |
| 2384 | color_type) != 0 && |
| 2385 | png_icc_check_tag_table(png_ptr, colorspace, name, profile_length, |
| 2386 | profile) != 0) |
| 2387 | { |
| 2388 | # ifdef PNG_sRGB_SUPPORTED |
| 2389 | /* If no sRGB support, don't try storing sRGB information */ |
| 2390 | png_icc_set_sRGB(png_ptr, colorspace, profile, 0); |
| 2391 | # endif |
| 2392 | return 1; |
| 2393 | } |
| 2394 | |
| 2395 | /* Failure case */ |
| 2396 | return 0; |
| 2397 | } |
| 2398 | #endif /* iCCP */ |
| 2399 | |
| 2400 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED |
| 2401 | void /* PRIVATE */ |
| 2402 | png_colorspace_set_rgb_coefficients(png_structrp png_ptr) |
| 2403 | { |
| 2404 | /* Set the rgb_to_gray coefficients from the colorspace. */ |
| 2405 | if (png_ptr->rgb_to_gray_coefficients_set == 0 && |
| 2406 | (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0) |
| 2407 | { |
| 2408 | /* png_set_background has not been called, get the coefficients from the Y |
| 2409 | * values of the colorspace colorants. |
| 2410 | */ |
| 2411 | png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y; |
| 2412 | png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y; |
| 2413 | png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y; |
| 2414 | png_fixed_point total = r+g+b; |
| 2415 | |
| 2416 | if (total > 0 && |
| 2417 | r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 && |
| 2418 | g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 && |
| 2419 | b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 && |
| 2420 | r+g+b <= 32769) |
| 2421 | { |
| 2422 | /* We allow 0 coefficients here. r+g+b may be 32769 if two or |
| 2423 | * all of the coefficients were rounded up. Handle this by |
| 2424 | * reducing the *largest* coefficient by 1; this matches the |
| 2425 | * approach used for the default coefficients in pngrtran.c |
| 2426 | */ |
| 2427 | int add = 0; |
| 2428 | |
| 2429 | if (r+g+b > 32768) |
| 2430 | add = -1; |
| 2431 | else if (r+g+b < 32768) |
| 2432 | add = 1; |
| 2433 | |
| 2434 | if (add != 0) |
| 2435 | { |
| 2436 | if (g >= r && g >= b) |
| 2437 | g += add; |
| 2438 | else if (r >= g && r >= b) |
| 2439 | r += add; |
| 2440 | else |
| 2441 | b += add; |
| 2442 | } |
| 2443 | |
| 2444 | /* Check for an internal error. */ |
| 2445 | if (r+g+b != 32768) |
| 2446 | png_error(png_ptr, |
| 2447 | "internal error handling cHRM coefficients"); |
| 2448 | |
| 2449 | else |
| 2450 | { |
| 2451 | png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r; |
| 2452 | png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g; |
| 2453 | } |
| 2454 | } |
| 2455 | |
| 2456 | /* This is a png_error at present even though it could be ignored - |
| 2457 | * it should never happen, but it is important that if it does, the |
| 2458 | * bug is fixed. |
| 2459 | */ |
| 2460 | else |
| 2461 | png_error(png_ptr, "internal error handling cHRM->XYZ"); |
| 2462 | } |
| 2463 | } |
| 2464 | #endif /* READ_RGB_TO_GRAY */ |
| 2465 | |
| 2466 | #endif /* COLORSPACE */ |
| 2467 | |
| 2468 | #ifdef __GNUC__ |
| 2469 | /* This exists solely to work round a warning from GNU C. */ |
| 2470 | static int /* PRIVATE */ |
| 2471 | png_gt(size_t a, size_t b) |
| 2472 | { |
| 2473 | return a > b; |
| 2474 | } |
| 2475 | #else |
| 2476 | # define png_gt(a,b) ((a) > (b)) |
| 2477 | #endif |
| 2478 | |
| 2479 | void /* PRIVATE */ |
| 2480 | png_check_IHDR(png_const_structrp png_ptr, |
| 2481 | png_uint_32 width, png_uint_32 height, int bit_depth, |
| 2482 | int color_type, int interlace_type, int compression_type, |
| 2483 | int filter_type) |
| 2484 | { |
| 2485 | int error = 0; |
| 2486 | |
| 2487 | /* Check for width and height valid values */ |
| 2488 | if (width == 0) |
| 2489 | { |
| 2490 | png_warning(png_ptr, "Image width is zero in IHDR"); |
| 2491 | error = 1; |
| 2492 | } |
| 2493 | |
| 2494 | if (width > PNG_UINT_31_MAX) |
| 2495 | { |
| 2496 | png_warning(png_ptr, "Invalid image width in IHDR"); |
| 2497 | error = 1; |
| 2498 | } |
| 2499 | |
| 2500 | if (png_gt(((width + 7) & (~7)), |
| 2501 | ((PNG_SIZE_MAX |
| 2502 | - 48 /* big_row_buf hack */ |
| 2503 | - 1) /* filter byte */ |
| 2504 | / 8) /* 8-byte RGBA pixels */ |
| 2505 | - 1)) /* extra max_pixel_depth pad */ |
| 2506 | { |
| 2507 | /* The size of the row must be within the limits of this architecture. |
| 2508 | * Because the read code can perform arbitrary transformations the |
| 2509 | * maximum size is checked here. Because the code in png_read_start_row |
| 2510 | * adds extra space "for safety's sake" in several places a conservative |
| 2511 | * limit is used here. |
| 2512 | * |
| 2513 | * NOTE: it would be far better to check the size that is actually used, |
| 2514 | * but the effect in the real world is minor and the changes are more |
| 2515 | * extensive, therefore much more dangerous and much more difficult to |
| 2516 | * write in a way that avoids compiler warnings. |
| 2517 | */ |
| 2518 | png_warning(png_ptr, "Image width is too large for this architecture"); |
| 2519 | error = 1; |
| 2520 | } |
| 2521 | |
| 2522 | #ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| 2523 | if (width > png_ptr->user_width_max) |
| 2524 | #else |
| 2525 | if (width > PNG_USER_WIDTH_MAX) |
| 2526 | #endif |
| 2527 | { |
| 2528 | png_warning(png_ptr, "Image width exceeds user limit in IHDR"); |
| 2529 | error = 1; |
| 2530 | } |
| 2531 | |
| 2532 | if (height == 0) |
| 2533 | { |
| 2534 | png_warning(png_ptr, "Image height is zero in IHDR"); |
| 2535 | error = 1; |
| 2536 | } |
| 2537 | |
| 2538 | if (height > PNG_UINT_31_MAX) |
| 2539 | { |
| 2540 | png_warning(png_ptr, "Invalid image height in IHDR"); |
| 2541 | error = 1; |
| 2542 | } |
| 2543 | |
| 2544 | #ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| 2545 | if (height > png_ptr->user_height_max) |
| 2546 | #else |
| 2547 | if (height > PNG_USER_HEIGHT_MAX) |
| 2548 | #endif |
| 2549 | { |
| 2550 | png_warning(png_ptr, "Image height exceeds user limit in IHDR"); |
| 2551 | error = 1; |
| 2552 | } |
| 2553 | |
| 2554 | /* Check other values */ |
| 2555 | if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && |
| 2556 | bit_depth != 8 && bit_depth != 16) |
| 2557 | { |
| 2558 | png_warning(png_ptr, "Invalid bit depth in IHDR"); |
| 2559 | error = 1; |
| 2560 | } |
| 2561 | |
| 2562 | if (color_type < 0 || color_type == 1 || |
| 2563 | color_type == 5 || color_type > 6) |
| 2564 | { |
| 2565 | png_warning(png_ptr, "Invalid color type in IHDR"); |
| 2566 | error = 1; |
| 2567 | } |
| 2568 | |
| 2569 | if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) || |
| 2570 | ((color_type == PNG_COLOR_TYPE_RGB || |
| 2571 | color_type == PNG_COLOR_TYPE_GRAY_ALPHA || |
| 2572 | color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8)) |
| 2573 | { |
| 2574 | png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR"); |
| 2575 | error = 1; |
| 2576 | } |
| 2577 | |
| 2578 | if (interlace_type >= PNG_INTERLACE_LAST) |
| 2579 | { |
| 2580 | png_warning(png_ptr, "Unknown interlace method in IHDR"); |
| 2581 | error = 1; |
| 2582 | } |
| 2583 | |
| 2584 | if (compression_type != PNG_COMPRESSION_TYPE_BASE) |
| 2585 | { |
| 2586 | png_warning(png_ptr, "Unknown compression method in IHDR"); |
| 2587 | error = 1; |
| 2588 | } |
| 2589 | |
| 2590 | #ifdef PNG_MNG_FEATURES_SUPPORTED |
| 2591 | /* Accept filter_method 64 (intrapixel differencing) only if |
| 2592 | * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and |
| 2593 | * 2. Libpng did not read a PNG signature (this filter_method is only |
| 2594 | * used in PNG datastreams that are embedded in MNG datastreams) and |
| 2595 | * 3. The application called png_permit_mng_features with a mask that |
| 2596 | * included PNG_FLAG_MNG_FILTER_64 and |
| 2597 | * 4. The filter_method is 64 and |
| 2598 | * 5. The color_type is RGB or RGBA |
| 2599 | */ |
| 2600 | if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && |
| 2601 | png_ptr->mng_features_permitted != 0) |
| 2602 | png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); |
| 2603 | |
| 2604 | if (filter_type != PNG_FILTER_TYPE_BASE) |
| 2605 | { |
| 2606 | if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 && |
| 2607 | (filter_type == PNG_INTRAPIXEL_DIFFERENCING) && |
| 2608 | ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && |
| 2609 | (color_type == PNG_COLOR_TYPE_RGB || |
| 2610 | color_type == PNG_COLOR_TYPE_RGB_ALPHA))) |
| 2611 | { |
| 2612 | png_warning(png_ptr, "Unknown filter method in IHDR"); |
| 2613 | error = 1; |
| 2614 | } |
| 2615 | |
| 2616 | if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0) |
| 2617 | { |
| 2618 | png_warning(png_ptr, "Invalid filter method in IHDR"); |
| 2619 | error = 1; |
| 2620 | } |
| 2621 | } |
| 2622 | |
| 2623 | #else |
| 2624 | if (filter_type != PNG_FILTER_TYPE_BASE) |
| 2625 | { |
| 2626 | png_warning(png_ptr, "Unknown filter method in IHDR"); |
| 2627 | error = 1; |
| 2628 | } |
| 2629 | #endif |
| 2630 | |
| 2631 | if (error == 1) |
| 2632 | png_error(png_ptr, "Invalid IHDR data"); |
| 2633 | } |
| 2634 | |
| 2635 | #if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) |
| 2636 | /* ASCII to fp functions */ |
| 2637 | /* Check an ASCII formated floating point value, see the more detailed |
| 2638 | * comments in pngpriv.h |
| 2639 | */ |
| 2640 | /* The following is used internally to preserve the sticky flags */ |
| 2641 | #define png_fp_add(state, flags) ((state) |= (flags)) |
| 2642 | #define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY)) |
| 2643 | |
| 2644 | int /* PRIVATE */ |
| 2645 | png_check_fp_number(png_const_charp string, png_size_t size, int *statep, |
| 2646 | png_size_tp whereami) |
| 2647 | { |
| 2648 | int state = *statep; |
| 2649 | png_size_t i = *whereami; |
| 2650 | |
| 2651 | while (i < size) |
| 2652 | { |
| 2653 | int type; |
| 2654 | /* First find the type of the next character */ |
| 2655 | switch (string[i]) |
| 2656 | { |
| 2657 | case 43: type = PNG_FP_SAW_SIGN; break; |
| 2658 | case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break; |
| 2659 | case 46: type = PNG_FP_SAW_DOT; break; |
| 2660 | case 48: type = PNG_FP_SAW_DIGIT; break; |
| 2661 | case 49: case 50: case 51: case 52: |
| 2662 | case 53: case 54: case 55: case 56: |
| 2663 | case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break; |
| 2664 | case 69: |
| 2665 | case 101: type = PNG_FP_SAW_E; break; |
| 2666 | default: goto PNG_FP_End; |
| 2667 | } |
| 2668 | |
| 2669 | /* Now deal with this type according to the current |
| 2670 | * state, the type is arranged to not overlap the |
| 2671 | * bits of the PNG_FP_STATE. |
| 2672 | */ |
| 2673 | switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY)) |
| 2674 | { |
| 2675 | case PNG_FP_INTEGER + PNG_FP_SAW_SIGN: |
| 2676 | if ((state & PNG_FP_SAW_ANY) != 0) |
| 2677 | goto PNG_FP_End; /* not a part of the number */ |
| 2678 | |
| 2679 | png_fp_add(state, type); |
| 2680 | break; |
| 2681 | |
| 2682 | case PNG_FP_INTEGER + PNG_FP_SAW_DOT: |
| 2683 | /* Ok as trailer, ok as lead of fraction. */ |
| 2684 | if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */ |
| 2685 | goto PNG_FP_End; |
| 2686 | |
| 2687 | else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */ |
| 2688 | png_fp_add(state, type); |
| 2689 | |
| 2690 | else |
| 2691 | png_fp_set(state, PNG_FP_FRACTION | type); |
| 2692 | |
| 2693 | break; |
| 2694 | |
| 2695 | case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT: |
| 2696 | if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */ |
| 2697 | png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT); |
| 2698 | |
| 2699 | png_fp_add(state, type | PNG_FP_WAS_VALID); |
| 2700 | |
| 2701 | break; |
| 2702 | |
| 2703 | case PNG_FP_INTEGER + PNG_FP_SAW_E: |
| 2704 | if ((state & PNG_FP_SAW_DIGIT) == 0) |
| 2705 | goto PNG_FP_End; |
| 2706 | |
| 2707 | png_fp_set(state, PNG_FP_EXPONENT); |
| 2708 | |
| 2709 | break; |
| 2710 | |
| 2711 | /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN: |
| 2712 | goto PNG_FP_End; ** no sign in fraction */ |
| 2713 | |
| 2714 | /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT: |
| 2715 | goto PNG_FP_End; ** Because SAW_DOT is always set */ |
| 2716 | |
| 2717 | case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT: |
| 2718 | png_fp_add(state, type | PNG_FP_WAS_VALID); |
| 2719 | break; |
| 2720 | |
| 2721 | case PNG_FP_FRACTION + PNG_FP_SAW_E: |
| 2722 | /* This is correct because the trailing '.' on an |
| 2723 | * integer is handled above - so we can only get here |
| 2724 | * with the sequence ".E" (with no preceding digits). |
| 2725 | */ |
| 2726 | if ((state & PNG_FP_SAW_DIGIT) == 0) |
| 2727 | goto PNG_FP_End; |
| 2728 | |
| 2729 | png_fp_set(state, PNG_FP_EXPONENT); |
| 2730 | |
| 2731 | break; |
| 2732 | |
| 2733 | case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN: |
| 2734 | if ((state & PNG_FP_SAW_ANY) != 0) |
| 2735 | goto PNG_FP_End; /* not a part of the number */ |
| 2736 | |
| 2737 | png_fp_add(state, PNG_FP_SAW_SIGN); |
| 2738 | |
| 2739 | break; |
| 2740 | |
| 2741 | /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT: |
| 2742 | goto PNG_FP_End; */ |
| 2743 | |
| 2744 | case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT: |
| 2745 | png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID); |
| 2746 | |
| 2747 | break; |
| 2748 | |
| 2749 | /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E: |
| 2750 | goto PNG_FP_End; */ |
| 2751 | |
| 2752 | default: goto PNG_FP_End; /* I.e. break 2 */ |
| 2753 | } |
| 2754 | |
| 2755 | /* The character seems ok, continue. */ |
| 2756 | ++i; |
| 2757 | } |
| 2758 | |
| 2759 | PNG_FP_End: |
| 2760 | /* Here at the end, update the state and return the correct |
| 2761 | * return code. |
| 2762 | */ |
| 2763 | *statep = state; |
| 2764 | *whereami = i; |
| 2765 | |
| 2766 | return (state & PNG_FP_SAW_DIGIT) != 0; |
| 2767 | } |
| 2768 | |
| 2769 | |
| 2770 | /* The same but for a complete string. */ |
| 2771 | int |
| 2772 | png_check_fp_string(png_const_charp string, png_size_t size) |
| 2773 | { |
| 2774 | int state=0; |
| 2775 | png_size_t char_index=0; |
| 2776 | |
| 2777 | if (png_check_fp_number(string, size, &state, &char_index) != 0 && |
| 2778 | (char_index == size || string[char_index] == 0)) |
| 2779 | return state /* must be non-zero - see above */; |
| 2780 | |
| 2781 | return 0; /* i.e. fail */ |
| 2782 | } |
| 2783 | #endif /* pCAL || sCAL */ |
| 2784 | |
| 2785 | #ifdef PNG_sCAL_SUPPORTED |
| 2786 | # ifdef PNG_FLOATING_POINT_SUPPORTED |
| 2787 | /* Utility used below - a simple accurate power of ten from an integral |
| 2788 | * exponent. |
| 2789 | */ |
| 2790 | static double |
| 2791 | png_pow10(int power) |
| 2792 | { |
| 2793 | int recip = 0; |
| 2794 | double d = 1; |
| 2795 | |
| 2796 | /* Handle negative exponent with a reciprocal at the end because |
| 2797 | * 10 is exact whereas .1 is inexact in base 2 |
| 2798 | */ |
| 2799 | if (power < 0) |
| 2800 | { |
| 2801 | if (power < DBL_MIN_10_EXP) return 0; |
| 2802 | recip = 1, power = -power; |
| 2803 | } |
| 2804 | |
| 2805 | if (power > 0) |
| 2806 | { |
| 2807 | /* Decompose power bitwise. */ |
| 2808 | double mult = 10; |
| 2809 | do |
| 2810 | { |
| 2811 | if (power & 1) d *= mult; |
| 2812 | mult *= mult; |
| 2813 | power >>= 1; |
| 2814 | } |
| 2815 | while (power > 0); |
| 2816 | |
| 2817 | if (recip != 0) d = 1/d; |
| 2818 | } |
| 2819 | /* else power is 0 and d is 1 */ |
| 2820 | |
| 2821 | return d; |
| 2822 | } |
| 2823 | |
| 2824 | /* Function to format a floating point value in ASCII with a given |
| 2825 | * precision. |
| 2826 | */ |
| 2827 | void /* PRIVATE */ |
| 2828 | png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size, |
| 2829 | double fp, unsigned int precision) |
| 2830 | { |
| 2831 | /* We use standard functions from math.h, but not printf because |
| 2832 | * that would require stdio. The caller must supply a buffer of |
| 2833 | * sufficient size or we will png_error. The tests on size and |
| 2834 | * the space in ascii[] consumed are indicated below. |
| 2835 | */ |
| 2836 | if (precision < 1) |
| 2837 | precision = DBL_DIG; |
| 2838 | |
| 2839 | /* Enforce the limit of the implementation precision too. */ |
| 2840 | if (precision > DBL_DIG+1) |
| 2841 | precision = DBL_DIG+1; |
| 2842 | |
| 2843 | /* Basic sanity checks */ |
| 2844 | if (size >= precision+5) /* See the requirements below. */ |
| 2845 | { |
| 2846 | if (fp < 0) |
| 2847 | { |
| 2848 | fp = -fp; |
| 2849 | *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */ |
| 2850 | --size; |
| 2851 | } |
| 2852 | |
| 2853 | if (fp >= DBL_MIN && fp <= DBL_MAX) |
| 2854 | { |
| 2855 | int exp_b10; /* A base 10 exponent */ |
| 2856 | double base; /* 10^exp_b10 */ |
| 2857 | |
| 2858 | /* First extract a base 10 exponent of the number, |
| 2859 | * the calculation below rounds down when converting |
| 2860 | * from base 2 to base 10 (multiply by log10(2) - |
| 2861 | * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to |
| 2862 | * be increased. Note that the arithmetic shift |
| 2863 | * performs a floor() unlike C arithmetic - using a |
| 2864 | * C multiply would break the following for negative |
| 2865 | * exponents. |
| 2866 | */ |
| 2867 | (void)frexp(fp, &exp_b10); /* exponent to base 2 */ |
| 2868 | |
| 2869 | exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */ |
| 2870 | |
| 2871 | /* Avoid underflow here. */ |
| 2872 | base = png_pow10(exp_b10); /* May underflow */ |
| 2873 | |
| 2874 | while (base < DBL_MIN || base < fp) |
| 2875 | { |
| 2876 | /* And this may overflow. */ |
| 2877 | double test = png_pow10(exp_b10+1); |
| 2878 | |
| 2879 | if (test <= DBL_MAX) |
| 2880 | ++exp_b10, base = test; |
| 2881 | |
| 2882 | else |
| 2883 | break; |
| 2884 | } |
| 2885 | |
| 2886 | /* Normalize fp and correct exp_b10, after this fp is in the |
| 2887 | * range [.1,1) and exp_b10 is both the exponent and the digit |
| 2888 | * *before* which the decimal point should be inserted |
| 2889 | * (starting with 0 for the first digit). Note that this |
| 2890 | * works even if 10^exp_b10 is out of range because of the |
| 2891 | * test on DBL_MAX above. |
| 2892 | */ |
| 2893 | fp /= base; |
| 2894 | while (fp >= 1) fp /= 10, ++exp_b10; |
| 2895 | |
| 2896 | /* Because of the code above fp may, at this point, be |
| 2897 | * less than .1, this is ok because the code below can |
| 2898 | * handle the leading zeros this generates, so no attempt |
| 2899 | * is made to correct that here. |
| 2900 | */ |
| 2901 | |
| 2902 | { |
| 2903 | unsigned int czero, clead, cdigits; |
| 2904 | char exponent[10]; |
| 2905 | |
| 2906 | /* Allow up to two leading zeros - this will not lengthen |
| 2907 | * the number compared to using E-n. |
| 2908 | */ |
| 2909 | if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */ |
| 2910 | { |
| 2911 | czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */ |
| 2912 | exp_b10 = 0; /* Dot added below before first output. */ |
| 2913 | } |
| 2914 | else |
| 2915 | czero = 0; /* No zeros to add */ |
| 2916 | |
| 2917 | /* Generate the digit list, stripping trailing zeros and |
| 2918 | * inserting a '.' before a digit if the exponent is 0. |
| 2919 | */ |
| 2920 | clead = czero; /* Count of leading zeros */ |
| 2921 | cdigits = 0; /* Count of digits in list. */ |
| 2922 | |
| 2923 | do |
| 2924 | { |
| 2925 | double d; |
| 2926 | |
| 2927 | fp *= 10; |
| 2928 | /* Use modf here, not floor and subtract, so that |
| 2929 | * the separation is done in one step. At the end |
| 2930 | * of the loop don't break the number into parts so |
| 2931 | * that the final digit is rounded. |
| 2932 | */ |
| 2933 | if (cdigits+czero+1 < precision+clead) |
| 2934 | fp = modf(fp, &d); |
| 2935 | |
| 2936 | else |
| 2937 | { |
| 2938 | d = floor(fp + .5); |
| 2939 | |
| 2940 | if (d > 9) |
| 2941 | { |
| 2942 | /* Rounding up to 10, handle that here. */ |
| 2943 | if (czero > 0) |
| 2944 | { |
| 2945 | --czero, d = 1; |
| 2946 | if (cdigits == 0) --clead; |
| 2947 | } |
| 2948 | else |
| 2949 | { |
| 2950 | while (cdigits > 0 && d > 9) |
| 2951 | { |
| 2952 | int ch = *--ascii; |
| 2953 | |
| 2954 | if (exp_b10 != (-1)) |
| 2955 | ++exp_b10; |
| 2956 | |
| 2957 | else if (ch == 46) |
| 2958 | { |
| 2959 | ch = *--ascii, ++size; |
| 2960 | /* Advance exp_b10 to '1', so that the |
| 2961 | * decimal point happens after the |
| 2962 | * previous digit. |
| 2963 | */ |
| 2964 | exp_b10 = 1; |
| 2965 | } |
| 2966 | |
| 2967 | --cdigits; |
| 2968 | d = ch - 47; /* I.e. 1+(ch-48) */ |
| 2969 | } |
| 2970 | |
| 2971 | /* Did we reach the beginning? If so adjust the |
| 2972 | * exponent but take into account the leading |
| 2973 | * decimal point. |
| 2974 | */ |
| 2975 | if (d > 9) /* cdigits == 0 */ |
| 2976 | { |
| 2977 | if (exp_b10 == (-1)) |
| 2978 | { |
| 2979 | /* Leading decimal point (plus zeros?), if |
| 2980 | * we lose the decimal point here it must |
| 2981 | * be reentered below. |
| 2982 | */ |
| 2983 | int ch = *--ascii; |
| 2984 | |
| 2985 | if (ch == 46) |
| 2986 | ++size, exp_b10 = 1; |
| 2987 | |
| 2988 | /* Else lost a leading zero, so 'exp_b10' is |
| 2989 | * still ok at (-1) |
| 2990 | */ |
| 2991 | } |
| 2992 | else |
| 2993 | ++exp_b10; |
| 2994 | |
| 2995 | /* In all cases we output a '1' */ |
| 2996 | d = 1; |
| 2997 | } |
| 2998 | } |
| 2999 | } |
| 3000 | fp = 0; /* Guarantees termination below. */ |
| 3001 | } |
| 3002 | |
| 3003 | if (d == 0) |
| 3004 | { |
| 3005 | ++czero; |
| 3006 | if (cdigits == 0) ++clead; |
| 3007 | } |
| 3008 | else |
| 3009 | { |
| 3010 | /* Included embedded zeros in the digit count. */ |
| 3011 | cdigits += czero - clead; |
| 3012 | clead = 0; |
| 3013 | |
| 3014 | while (czero > 0) |
| 3015 | { |
| 3016 | /* exp_b10 == (-1) means we just output the decimal |
| 3017 | * place - after the DP don't adjust 'exp_b10' any |
| 3018 | * more! |
| 3019 | */ |
| 3020 | if (exp_b10 != (-1)) |
| 3021 | { |
| 3022 | if (exp_b10 == 0) *ascii++ = 46, --size; |
| 3023 | /* PLUS 1: TOTAL 4 */ |
| 3024 | --exp_b10; |
| 3025 | } |
| 3026 | *ascii++ = 48, --czero; |
| 3027 | } |
| 3028 | |
| 3029 | if (exp_b10 != (-1)) |
| 3030 | { |
| 3031 | if (exp_b10 == 0) |
| 3032 | *ascii++ = 46, --size; /* counted above */ |
| 3033 | |
| 3034 | --exp_b10; |
| 3035 | } |
| 3036 | *ascii++ = (char)(48 + (int)d), ++cdigits; |
| 3037 | } |
| 3038 | } |
| 3039 | while (cdigits+czero < precision+clead && fp > DBL_MIN); |
| 3040 | |
| 3041 | /* The total output count (max) is now 4+precision */ |
| 3042 | |
| 3043 | /* Check for an exponent, if we don't need one we are |
| 3044 | * done and just need to terminate the string. At |
| 3045 | * this point exp_b10==(-1) is effectively if flag - it got |
| 3046 | * to '-1' because of the decrement after outputting |
| 3047 | * the decimal point above (the exponent required is |
| 3048 | * *not* -1!) |
| 3049 | */ |
| 3050 | if (exp_b10 >= (-1) && exp_b10 <= 2) |
| 3051 | { |
| 3052 | /* The following only happens if we didn't output the |
| 3053 | * leading zeros above for negative exponent, so this |
| 3054 | * doesn't add to the digit requirement. Note that the |
| 3055 | * two zeros here can only be output if the two leading |
| 3056 | * zeros were *not* output, so this doesn't increase |
| 3057 | * the output count. |
| 3058 | */ |
| 3059 | while (--exp_b10 >= 0) *ascii++ = 48; |
| 3060 | |
| 3061 | *ascii = 0; |
| 3062 | |
| 3063 | /* Total buffer requirement (including the '\0') is |
| 3064 | * 5+precision - see check at the start. |
| 3065 | */ |
| 3066 | return; |
| 3067 | } |
| 3068 | |
| 3069 | /* Here if an exponent is required, adjust size for |
| 3070 | * the digits we output but did not count. The total |
| 3071 | * digit output here so far is at most 1+precision - no |
| 3072 | * decimal point and no leading or trailing zeros have |
| 3073 | * been output. |
| 3074 | */ |
| 3075 | size -= cdigits; |
| 3076 | |
| 3077 | *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */ |
| 3078 | |
| 3079 | /* The following use of an unsigned temporary avoids ambiguities in |
| 3080 | * the signed arithmetic on exp_b10 and permits GCC at least to do |
| 3081 | * better optimization. |
| 3082 | */ |
| 3083 | { |
| 3084 | unsigned int uexp_b10; |
| 3085 | |
| 3086 | if (exp_b10 < 0) |
| 3087 | { |
| 3088 | *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */ |
| 3089 | uexp_b10 = -exp_b10; |
| 3090 | } |
| 3091 | |
| 3092 | else |
| 3093 | uexp_b10 = exp_b10; |
| 3094 | |
| 3095 | cdigits = 0; |
| 3096 | |
| 3097 | while (uexp_b10 > 0) |
| 3098 | { |
| 3099 | exponent[cdigits++] = (char)(48 + uexp_b10 % 10); |
| 3100 | uexp_b10 /= 10; |
| 3101 | } |
| 3102 | } |
| 3103 | |
| 3104 | /* Need another size check here for the exponent digits, so |
| 3105 | * this need not be considered above. |
| 3106 | */ |
| 3107 | if (size > cdigits) |
| 3108 | { |
| 3109 | while (cdigits > 0) *ascii++ = exponent[--cdigits]; |
| 3110 | |
| 3111 | *ascii = 0; |
| 3112 | |
| 3113 | return; |
| 3114 | } |
| 3115 | } |
| 3116 | } |
| 3117 | else if (!(fp >= DBL_MIN)) |
| 3118 | { |
| 3119 | *ascii++ = 48; /* '0' */ |
| 3120 | *ascii = 0; |
| 3121 | return; |
| 3122 | } |
| 3123 | else |
| 3124 | { |
| 3125 | *ascii++ = 105; /* 'i' */ |
| 3126 | *ascii++ = 110; /* 'n' */ |
| 3127 | *ascii++ = 102; /* 'f' */ |
| 3128 | *ascii = 0; |
| 3129 | return; |
| 3130 | } |
| 3131 | } |
| 3132 | |
| 3133 | /* Here on buffer too small. */ |
| 3134 | png_error(png_ptr, "ASCII conversion buffer too small"); |
| 3135 | } |
| 3136 | |
| 3137 | # endif /* FLOATING_POINT */ |
| 3138 | |
| 3139 | # ifdef PNG_FIXED_POINT_SUPPORTED |
| 3140 | /* Function to format a fixed point value in ASCII. |
| 3141 | */ |
| 3142 | void /* PRIVATE */ |
| 3143 | png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii, |
| 3144 | png_size_t size, png_fixed_point fp) |
| 3145 | { |
| 3146 | /* Require space for 10 decimal digits, a decimal point, a minus sign and a |
| 3147 | * trailing \0, 13 characters: |
| 3148 | */ |
| 3149 | if (size > 12) |
| 3150 | { |
| 3151 | png_uint_32 num; |
| 3152 | |
| 3153 | /* Avoid overflow here on the minimum integer. */ |
| 3154 | if (fp < 0) |
| 3155 | *ascii++ = 45, num = -fp; |
| 3156 | else |
| 3157 | num = fp; |
| 3158 | |
| 3159 | if (num <= 0x80000000) /* else overflowed */ |
| 3160 | { |
| 3161 | unsigned int ndigits = 0, first = 16 /* flag value */; |
| 3162 | char digits[10]; |
| 3163 | |
| 3164 | while (num) |
| 3165 | { |
| 3166 | /* Split the low digit off num: */ |
| 3167 | unsigned int tmp = num/10; |
| 3168 | num -= tmp*10; |
| 3169 | digits[ndigits++] = (char)(48 + num); |
| 3170 | /* Record the first non-zero digit, note that this is a number |
| 3171 | * starting at 1, it's not actually the array index. |
| 3172 | */ |
| 3173 | if (first == 16 && num > 0) |
| 3174 | first = ndigits; |
| 3175 | num = tmp; |
| 3176 | } |
| 3177 | |
| 3178 | if (ndigits > 0) |
| 3179 | { |
| 3180 | while (ndigits > 5) *ascii++ = digits[--ndigits]; |
| 3181 | /* The remaining digits are fractional digits, ndigits is '5' or |
| 3182 | * smaller at this point. It is certainly not zero. Check for a |
| 3183 | * non-zero fractional digit: |
| 3184 | */ |
| 3185 | if (first <= 5) |
| 3186 | { |
| 3187 | unsigned int i; |
| 3188 | *ascii++ = 46; /* decimal point */ |
| 3189 | /* ndigits may be <5 for small numbers, output leading zeros |
| 3190 | * then ndigits digits to first: |
| 3191 | */ |
| 3192 | i = 5; |
| 3193 | while (ndigits < i) *ascii++ = 48, --i; |
| 3194 | while (ndigits >= first) *ascii++ = digits[--ndigits]; |
| 3195 | /* Don't output the trailing zeros! */ |
| 3196 | } |
| 3197 | } |
| 3198 | else |
| 3199 | *ascii++ = 48; |
| 3200 | |
| 3201 | /* And null terminate the string: */ |
| 3202 | *ascii = 0; |
| 3203 | return; |
| 3204 | } |
| 3205 | } |
| 3206 | |
| 3207 | /* Here on buffer too small. */ |
| 3208 | png_error(png_ptr, "ASCII conversion buffer too small"); |
| 3209 | } |
| 3210 | # endif /* FIXED_POINT */ |
| 3211 | #endif /* SCAL */ |
| 3212 | |
| 3213 | #if defined(PNG_FLOATING_POINT_SUPPORTED) && \ |
| 3214 | !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \ |
| 3215 | (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \ |
| 3216 | defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \ |
| 3217 | defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \ |
| 3218 | (defined(PNG_sCAL_SUPPORTED) && \ |
| 3219 | defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)) |
| 3220 | png_fixed_point |
| 3221 | png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text) |
| 3222 | { |
| 3223 | double r = floor(100000 * fp + .5); |
| 3224 | |
| 3225 | if (r > 2147483647. || r < -2147483648.) |
| 3226 | png_fixed_error(png_ptr, text); |
| 3227 | |
| 3228 | # ifndef PNG_ERROR_TEXT_SUPPORTED |
| 3229 | PNG_UNUSED(text) |
| 3230 | # endif |
| 3231 | |
| 3232 | return (png_fixed_point)r; |
| 3233 | } |
| 3234 | #endif |
| 3235 | |
| 3236 | #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\ |
| 3237 | defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED) |
| 3238 | /* muldiv functions */ |
| 3239 | /* This API takes signed arguments and rounds the result to the nearest |
| 3240 | * integer (or, for a fixed point number - the standard argument - to |
| 3241 | * the nearest .00001). Overflow and divide by zero are signalled in |
| 3242 | * the result, a boolean - true on success, false on overflow. |
| 3243 | */ |
| 3244 | int |
| 3245 | png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times, |
| 3246 | png_int_32 divisor) |
| 3247 | { |
| 3248 | /* Return a * times / divisor, rounded. */ |
| 3249 | if (divisor != 0) |
| 3250 | { |
| 3251 | if (a == 0 || times == 0) |
| 3252 | { |
| 3253 | *res = 0; |
| 3254 | return 1; |
| 3255 | } |
| 3256 | else |
| 3257 | { |
| 3258 | #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3259 | double r = a; |
| 3260 | r *= times; |
| 3261 | r /= divisor; |
| 3262 | r = floor(r+.5); |
| 3263 | |
| 3264 | /* A png_fixed_point is a 32-bit integer. */ |
| 3265 | if (r <= 2147483647. && r >= -2147483648.) |
| 3266 | { |
| 3267 | *res = (png_fixed_point)r; |
| 3268 | return 1; |
| 3269 | } |
| 3270 | #else |
| 3271 | int negative = 0; |
| 3272 | png_uint_32 A, T, D; |
| 3273 | png_uint_32 s16, s32, s00; |
| 3274 | |
| 3275 | if (a < 0) |
| 3276 | negative = 1, A = -a; |
| 3277 | else |
| 3278 | A = a; |
| 3279 | |
| 3280 | if (times < 0) |
| 3281 | negative = !negative, T = -times; |
| 3282 | else |
| 3283 | T = times; |
| 3284 | |
| 3285 | if (divisor < 0) |
| 3286 | negative = !negative, D = -divisor; |
| 3287 | else |
| 3288 | D = divisor; |
| 3289 | |
| 3290 | /* Following can't overflow because the arguments only |
| 3291 | * have 31 bits each, however the result may be 32 bits. |
| 3292 | */ |
| 3293 | s16 = (A >> 16) * (T & 0xffff) + |
| 3294 | (A & 0xffff) * (T >> 16); |
| 3295 | /* Can't overflow because the a*times bit is only 30 |
| 3296 | * bits at most. |
| 3297 | */ |
| 3298 | s32 = (A >> 16) * (T >> 16) + (s16 >> 16); |
| 3299 | s00 = (A & 0xffff) * (T & 0xffff); |
| 3300 | |
| 3301 | s16 = (s16 & 0xffff) << 16; |
| 3302 | s00 += s16; |
| 3303 | |
| 3304 | if (s00 < s16) |
| 3305 | ++s32; /* carry */ |
| 3306 | |
| 3307 | if (s32 < D) /* else overflow */ |
| 3308 | { |
| 3309 | /* s32.s00 is now the 64-bit product, do a standard |
| 3310 | * division, we know that s32 < D, so the maximum |
| 3311 | * required shift is 31. |
| 3312 | */ |
| 3313 | int bitshift = 32; |
| 3314 | png_fixed_point result = 0; /* NOTE: signed */ |
| 3315 | |
| 3316 | while (--bitshift >= 0) |
| 3317 | { |
| 3318 | png_uint_32 d32, d00; |
| 3319 | |
| 3320 | if (bitshift > 0) |
| 3321 | d32 = D >> (32-bitshift), d00 = D << bitshift; |
| 3322 | |
| 3323 | else |
| 3324 | d32 = 0, d00 = D; |
| 3325 | |
| 3326 | if (s32 > d32) |
| 3327 | { |
| 3328 | if (s00 < d00) --s32; /* carry */ |
| 3329 | s32 -= d32, s00 -= d00, result += 1<<bitshift; |
| 3330 | } |
| 3331 | |
| 3332 | else |
| 3333 | if (s32 == d32 && s00 >= d00) |
| 3334 | s32 = 0, s00 -= d00, result += 1<<bitshift; |
| 3335 | } |
| 3336 | |
| 3337 | /* Handle the rounding. */ |
| 3338 | if (s00 >= (D >> 1)) |
| 3339 | ++result; |
| 3340 | |
| 3341 | if (negative != 0) |
| 3342 | result = -result; |
| 3343 | |
| 3344 | /* Check for overflow. */ |
| 3345 | if ((negative != 0 && result <= 0) || |
| 3346 | (negative == 0 && result >= 0)) |
| 3347 | { |
| 3348 | *res = result; |
| 3349 | return 1; |
| 3350 | } |
| 3351 | } |
| 3352 | #endif |
| 3353 | } |
| 3354 | } |
| 3355 | |
| 3356 | return 0; |
| 3357 | } |
| 3358 | #endif /* READ_GAMMA || INCH_CONVERSIONS */ |
| 3359 | |
| 3360 | #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED) |
| 3361 | /* The following is for when the caller doesn't much care about the |
| 3362 | * result. |
| 3363 | */ |
| 3364 | png_fixed_point |
| 3365 | png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times, |
| 3366 | png_int_32 divisor) |
| 3367 | { |
| 3368 | png_fixed_point result; |
| 3369 | |
| 3370 | if (png_muldiv(&result, a, times, divisor) != 0) |
| 3371 | return result; |
| 3372 | |
| 3373 | png_warning(png_ptr, "fixed point overflow ignored"); |
| 3374 | return 0; |
| 3375 | } |
| 3376 | #endif |
| 3377 | |
| 3378 | #ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */ |
| 3379 | /* Calculate a reciprocal, return 0 on div-by-zero or overflow. */ |
| 3380 | png_fixed_point |
| 3381 | png_reciprocal(png_fixed_point a) |
| 3382 | { |
| 3383 | #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3384 | double r = floor(1E10/a+.5); |
| 3385 | |
| 3386 | if (r <= 2147483647. && r >= -2147483648.) |
| 3387 | return (png_fixed_point)r; |
| 3388 | #else |
| 3389 | png_fixed_point res; |
| 3390 | |
| 3391 | if (png_muldiv(&res, 100000, 100000, a) != 0) |
| 3392 | return res; |
| 3393 | #endif |
| 3394 | |
| 3395 | return 0; /* error/overflow */ |
| 3396 | } |
| 3397 | |
| 3398 | /* This is the shared test on whether a gamma value is 'significant' - whether |
| 3399 | * it is worth doing gamma correction. |
| 3400 | */ |
| 3401 | int /* PRIVATE */ |
| 3402 | png_gamma_significant(png_fixed_point gamma_val) |
| 3403 | { |
| 3404 | return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED || |
| 3405 | gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED; |
| 3406 | } |
| 3407 | #endif |
| 3408 | |
| 3409 | #ifdef PNG_READ_GAMMA_SUPPORTED |
| 3410 | #ifdef PNG_16BIT_SUPPORTED |
| 3411 | /* A local convenience routine. */ |
| 3412 | static png_fixed_point |
| 3413 | png_product2(png_fixed_point a, png_fixed_point b) |
| 3414 | { |
| 3415 | /* The required result is 1/a * 1/b; the following preserves accuracy. */ |
| 3416 | #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3417 | double r = a * 1E-5; |
| 3418 | r *= b; |
| 3419 | r = floor(r+.5); |
| 3420 | |
| 3421 | if (r <= 2147483647. && r >= -2147483648.) |
| 3422 | return (png_fixed_point)r; |
| 3423 | #else |
| 3424 | png_fixed_point res; |
| 3425 | |
| 3426 | if (png_muldiv(&res, a, b, 100000) != 0) |
| 3427 | return res; |
| 3428 | #endif |
| 3429 | |
| 3430 | return 0; /* overflow */ |
| 3431 | } |
| 3432 | #endif /* 16BIT */ |
| 3433 | |
| 3434 | /* The inverse of the above. */ |
| 3435 | png_fixed_point |
| 3436 | png_reciprocal2(png_fixed_point a, png_fixed_point b) |
| 3437 | { |
| 3438 | /* The required result is 1/a * 1/b; the following preserves accuracy. */ |
| 3439 | #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3440 | if (a != 0 && b != 0) |
| 3441 | { |
| 3442 | double r = 1E15/a; |
| 3443 | r /= b; |
| 3444 | r = floor(r+.5); |
| 3445 | |
| 3446 | if (r <= 2147483647. && r >= -2147483648.) |
| 3447 | return (png_fixed_point)r; |
| 3448 | } |
| 3449 | #else |
| 3450 | /* This may overflow because the range of png_fixed_point isn't symmetric, |
| 3451 | * but this API is only used for the product of file and screen gamma so it |
| 3452 | * doesn't matter that the smallest number it can produce is 1/21474, not |
| 3453 | * 1/100000 |
| 3454 | */ |
| 3455 | png_fixed_point res = png_product2(a, b); |
| 3456 | |
| 3457 | if (res != 0) |
| 3458 | return png_reciprocal(res); |
| 3459 | #endif |
| 3460 | |
| 3461 | return 0; /* overflow */ |
| 3462 | } |
| 3463 | #endif /* READ_GAMMA */ |
| 3464 | |
| 3465 | #ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */ |
| 3466 | #ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3467 | /* Fixed point gamma. |
| 3468 | * |
| 3469 | * The code to calculate the tables used below can be found in the shell script |
| 3470 | * contrib/tools/intgamma.sh |
| 3471 | * |
| 3472 | * To calculate gamma this code implements fast log() and exp() calls using only |
| 3473 | * fixed point arithmetic. This code has sufficient precision for either 8-bit |
| 3474 | * or 16-bit sample values. |
| 3475 | * |
| 3476 | * The tables used here were calculated using simple 'bc' programs, but C double |
| 3477 | * precision floating point arithmetic would work fine. |
| 3478 | * |
| 3479 | * 8-bit log table |
| 3480 | * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to |
| 3481 | * 255, so it's the base 2 logarithm of a normalized 8-bit floating point |
| 3482 | * mantissa. The numbers are 32-bit fractions. |
| 3483 | */ |
| 3484 | static const png_uint_32 |
| 3485 | png_8bit_l2[128] = |
| 3486 | { |
| 3487 | 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U, |
| 3488 | 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U, |
| 3489 | 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U, |
| 3490 | 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U, |
| 3491 | 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U, |
| 3492 | 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U, |
| 3493 | 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U, |
| 3494 | 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U, |
| 3495 | 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U, |
| 3496 | 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U, |
| 3497 | 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U, |
| 3498 | 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U, |
| 3499 | 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U, |
| 3500 | 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U, |
| 3501 | 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U, |
| 3502 | 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U, |
| 3503 | 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U, |
| 3504 | 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U, |
| 3505 | 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U, |
| 3506 | 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U, |
| 3507 | 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U, |
| 3508 | 24347096U, 0U |
| 3509 | |
| 3510 | #if 0 |
| 3511 | /* The following are the values for 16-bit tables - these work fine for the |
| 3512 | * 8-bit conversions but produce very slightly larger errors in the 16-bit |
| 3513 | * log (about 1.2 as opposed to 0.7 absolute error in the final value). To |
| 3514 | * use these all the shifts below must be adjusted appropriately. |
| 3515 | */ |
| 3516 | 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054, |
| 3517 | 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803, |
| 3518 | 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068, |
| 3519 | 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782, |
| 3520 | 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887, |
| 3521 | 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339, |
| 3522 | 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098, |
| 3523 | 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132, |
| 3524 | 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415, |
| 3525 | 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523, |
| 3526 | 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495, |
| 3527 | 1119, 744, 372 |
| 3528 | #endif |
| 3529 | }; |
| 3530 | |
| 3531 | static png_int_32 |
| 3532 | png_log8bit(unsigned int x) |
| 3533 | { |
| 3534 | unsigned int lg2 = 0; |
| 3535 | /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log, |
| 3536 | * because the log is actually negate that means adding 1. The final |
| 3537 | * returned value thus has the range 0 (for 255 input) to 7.994 (for 1 |
| 3538 | * input), return -1 for the overflow (log 0) case, - so the result is |
| 3539 | * always at most 19 bits. |
| 3540 | */ |
| 3541 | if ((x &= 0xff) == 0) |
| 3542 | return -1; |
| 3543 | |
| 3544 | if ((x & 0xf0) == 0) |
| 3545 | lg2 = 4, x <<= 4; |
| 3546 | |
| 3547 | if ((x & 0xc0) == 0) |
| 3548 | lg2 += 2, x <<= 2; |
| 3549 | |
| 3550 | if ((x & 0x80) == 0) |
| 3551 | lg2 += 1, x <<= 1; |
| 3552 | |
| 3553 | /* result is at most 19 bits, so this cast is safe: */ |
| 3554 | return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16)); |
| 3555 | } |
| 3556 | |
| 3557 | /* The above gives exact (to 16 binary places) log2 values for 8-bit images, |
| 3558 | * for 16-bit images we use the most significant 8 bits of the 16-bit value to |
| 3559 | * get an approximation then multiply the approximation by a correction factor |
| 3560 | * determined by the remaining up to 8 bits. This requires an additional step |
| 3561 | * in the 16-bit case. |
| 3562 | * |
| 3563 | * We want log2(value/65535), we have log2(v'/255), where: |
| 3564 | * |
| 3565 | * value = v' * 256 + v'' |
| 3566 | * = v' * f |
| 3567 | * |
| 3568 | * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128 |
| 3569 | * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less |
| 3570 | * than 258. The final factor also needs to correct for the fact that our 8-bit |
| 3571 | * value is scaled by 255, whereas the 16-bit values must be scaled by 65535. |
| 3572 | * |
| 3573 | * This gives a final formula using a calculated value 'x' which is value/v' and |
| 3574 | * scaling by 65536 to match the above table: |
| 3575 | * |
| 3576 | * log2(x/257) * 65536 |
| 3577 | * |
| 3578 | * Since these numbers are so close to '1' we can use simple linear |
| 3579 | * interpolation between the two end values 256/257 (result -368.61) and 258/257 |
| 3580 | * (result 367.179). The values used below are scaled by a further 64 to give |
| 3581 | * 16-bit precision in the interpolation: |
| 3582 | * |
| 3583 | * Start (256): -23591 |
| 3584 | * Zero (257): 0 |
| 3585 | * End (258): 23499 |
| 3586 | */ |
| 3587 | #ifdef PNG_16BIT_SUPPORTED |
| 3588 | static png_int_32 |
| 3589 | png_log16bit(png_uint_32 x) |
| 3590 | { |
| 3591 | unsigned int lg2 = 0; |
| 3592 | |
| 3593 | /* As above, but now the input has 16 bits. */ |
| 3594 | if ((x &= 0xffff) == 0) |
| 3595 | return -1; |
| 3596 | |
| 3597 | if ((x & 0xff00) == 0) |
| 3598 | lg2 = 8, x <<= 8; |
| 3599 | |
| 3600 | if ((x & 0xf000) == 0) |
| 3601 | lg2 += 4, x <<= 4; |
| 3602 | |
| 3603 | if ((x & 0xc000) == 0) |
| 3604 | lg2 += 2, x <<= 2; |
| 3605 | |
| 3606 | if ((x & 0x8000) == 0) |
| 3607 | lg2 += 1, x <<= 1; |
| 3608 | |
| 3609 | /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional |
| 3610 | * value. |
| 3611 | */ |
| 3612 | lg2 <<= 28; |
| 3613 | lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4; |
| 3614 | |
| 3615 | /* Now we need to interpolate the factor, this requires a division by the top |
| 3616 | * 8 bits. Do this with maximum precision. |
| 3617 | */ |
| 3618 | x = ((x << 16) + (x >> 9)) / (x >> 8); |
| 3619 | |
| 3620 | /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24, |
| 3621 | * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly |
| 3622 | * 16 bits to interpolate to get the low bits of the result. Round the |
| 3623 | * answer. Note that the end point values are scaled by 64 to retain overall |
| 3624 | * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust |
| 3625 | * the overall scaling by 6-12. Round at every step. |
| 3626 | */ |
| 3627 | x -= 1U << 24; |
| 3628 | |
| 3629 | if (x <= 65536U) /* <= '257' */ |
| 3630 | lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12); |
| 3631 | |
| 3632 | else |
| 3633 | lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12); |
| 3634 | |
| 3635 | /* Safe, because the result can't have more than 20 bits: */ |
| 3636 | return (png_int_32)((lg2 + 2048) >> 12); |
| 3637 | } |
| 3638 | #endif /* 16BIT */ |
| 3639 | |
| 3640 | /* The 'exp()' case must invert the above, taking a 20-bit fixed point |
| 3641 | * logarithmic value and returning a 16 or 8-bit number as appropriate. In |
| 3642 | * each case only the low 16 bits are relevant - the fraction - since the |
| 3643 | * integer bits (the top 4) simply determine a shift. |
| 3644 | * |
| 3645 | * The worst case is the 16-bit distinction between 65535 and 65534. This |
| 3646 | * requires perhaps spurious accuracy in the decoding of the logarithm to |
| 3647 | * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance |
| 3648 | * of getting this accuracy in practice. |
| 3649 | * |
| 3650 | * To deal with this the following exp() function works out the exponent of the |
| 3651 | * frational part of the logarithm by using an accurate 32-bit value from the |
| 3652 | * top four fractional bits then multiplying in the remaining bits. |
| 3653 | */ |
| 3654 | static const png_uint_32 |
| 3655 | png_32bit_exp[16] = |
| 3656 | { |
| 3657 | /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */ |
| 3658 | 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U, |
| 3659 | 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U, |
| 3660 | 2553802834U, 2445529972U, 2341847524U, 2242560872U |
| 3661 | }; |
| 3662 | |
| 3663 | /* Adjustment table; provided to explain the numbers in the code below. */ |
| 3664 | #if 0 |
| 3665 | for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"} |
| 3666 | 11 44937.64284865548751208448 |
| 3667 | 10 45180.98734845585101160448 |
| 3668 | 9 45303.31936980687359311872 |
| 3669 | 8 45364.65110595323018870784 |
| 3670 | 7 45395.35850361789624614912 |
| 3671 | 6 45410.72259715102037508096 |
| 3672 | 5 45418.40724413220722311168 |
| 3673 | 4 45422.25021786898173001728 |
| 3674 | 3 45424.17186732298419044352 |
| 3675 | 2 45425.13273269940811464704 |
| 3676 | 1 45425.61317555035558641664 |
| 3677 | 0 45425.85339951654943850496 |
| 3678 | #endif |
| 3679 | |
| 3680 | static png_uint_32 |
| 3681 | png_exp(png_fixed_point x) |
| 3682 | { |
| 3683 | if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */ |
| 3684 | { |
| 3685 | /* Obtain a 4-bit approximation */ |
| 3686 | png_uint_32 e = png_32bit_exp[(x >> 12) & 0x0f]; |
| 3687 | |
| 3688 | /* Incorporate the low 12 bits - these decrease the returned value by |
| 3689 | * multiplying by a number less than 1 if the bit is set. The multiplier |
| 3690 | * is determined by the above table and the shift. Notice that the values |
| 3691 | * converge on 45426 and this is used to allow linear interpolation of the |
| 3692 | * low bits. |
| 3693 | */ |
| 3694 | if (x & 0x800) |
| 3695 | e -= (((e >> 16) * 44938U) + 16U) >> 5; |
| 3696 | |
| 3697 | if (x & 0x400) |
| 3698 | e -= (((e >> 16) * 45181U) + 32U) >> 6; |
| 3699 | |
| 3700 | if (x & 0x200) |
| 3701 | e -= (((e >> 16) * 45303U) + 64U) >> 7; |
| 3702 | |
| 3703 | if (x & 0x100) |
| 3704 | e -= (((e >> 16) * 45365U) + 128U) >> 8; |
| 3705 | |
| 3706 | if (x & 0x080) |
| 3707 | e -= (((e >> 16) * 45395U) + 256U) >> 9; |
| 3708 | |
| 3709 | if (x & 0x040) |
| 3710 | e -= (((e >> 16) * 45410U) + 512U) >> 10; |
| 3711 | |
| 3712 | /* And handle the low 6 bits in a single block. */ |
| 3713 | e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9; |
| 3714 | |
| 3715 | /* Handle the upper bits of x. */ |
| 3716 | e >>= x >> 16; |
| 3717 | return e; |
| 3718 | } |
| 3719 | |
| 3720 | /* Check for overflow */ |
| 3721 | if (x <= 0) |
| 3722 | return png_32bit_exp[0]; |
| 3723 | |
| 3724 | /* Else underflow */ |
| 3725 | return 0; |
| 3726 | } |
| 3727 | |
| 3728 | static png_byte |
| 3729 | png_exp8bit(png_fixed_point lg2) |
| 3730 | { |
| 3731 | /* Get a 32-bit value: */ |
| 3732 | png_uint_32 x = png_exp(lg2); |
| 3733 | |
| 3734 | /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the |
| 3735 | * second, rounding, step can't overflow because of the first, subtraction, |
| 3736 | * step. |
| 3737 | */ |
| 3738 | x -= x >> 8; |
| 3739 | return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff); |
| 3740 | } |
| 3741 | |
| 3742 | #ifdef PNG_16BIT_SUPPORTED |
| 3743 | static png_uint_16 |
| 3744 | png_exp16bit(png_fixed_point lg2) |
| 3745 | { |
| 3746 | /* Get a 32-bit value: */ |
| 3747 | png_uint_32 x = png_exp(lg2); |
| 3748 | |
| 3749 | /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */ |
| 3750 | x -= x >> 16; |
| 3751 | return (png_uint_16)((x + 32767U) >> 16); |
| 3752 | } |
| 3753 | #endif /* 16BIT */ |
| 3754 | #endif /* FLOATING_ARITHMETIC */ |
| 3755 | |
| 3756 | png_byte |
| 3757 | png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val) |
| 3758 | { |
| 3759 | if (value > 0 && value < 255) |
| 3760 | { |
| 3761 | # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3762 | /* 'value' is unsigned, ANSI-C90 requires the compiler to correctly |
| 3763 | * convert this to a floating point value. This includes values that |
| 3764 | * would overflow if 'value' were to be converted to 'int'. |
| 3765 | * |
| 3766 | * Apparently GCC, however, does an intermediate conversion to (int) |
| 3767 | * on some (ARM) but not all (x86) platforms, possibly because of |
| 3768 | * hardware FP limitations. (E.g. if the hardware conversion always |
| 3769 | * assumes the integer register contains a signed value.) This results |
| 3770 | * in ANSI-C undefined behavior for large values. |
| 3771 | * |
| 3772 | * Other implementations on the same machine might actually be ANSI-C90 |
| 3773 | * conformant and therefore compile spurious extra code for the large |
| 3774 | * values. |
| 3775 | * |
| 3776 | * We can be reasonably sure that an unsigned to float conversion |
| 3777 | * won't be faster than an int to float one. Therefore this code |
| 3778 | * assumes responsibility for the undefined behavior, which it knows |
| 3779 | * can't happen because of the check above. |
| 3780 | * |
| 3781 | * Note the argument to this routine is an (unsigned int) because, on |
| 3782 | * 16-bit platforms, it is assigned a value which might be out of |
| 3783 | * range for an (int); that would result in undefined behavior in the |
| 3784 | * caller if the *argument* ('value') were to be declared (int). |
| 3785 | */ |
| 3786 | double r = floor(255*pow((int)/*SAFE*/value/255.,gamma_val*.00001)+.5); |
| 3787 | return (png_byte)r; |
| 3788 | # else |
| 3789 | png_int_32 lg2 = png_log8bit(value); |
| 3790 | png_fixed_point res; |
| 3791 | |
| 3792 | if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0) |
| 3793 | return png_exp8bit(res); |
| 3794 | |
| 3795 | /* Overflow. */ |
| 3796 | value = 0; |
| 3797 | # endif |
| 3798 | } |
| 3799 | |
| 3800 | return (png_byte)(value & 0xff); |
| 3801 | } |
| 3802 | |
| 3803 | #ifdef PNG_16BIT_SUPPORTED |
| 3804 | png_uint_16 |
| 3805 | png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val) |
| 3806 | { |
| 3807 | if (value > 0 && value < 65535) |
| 3808 | { |
| 3809 | # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3810 | /* The same (unsigned int)->(double) constraints apply here as above, |
| 3811 | * however in this case the (unsigned int) to (int) conversion can |
| 3812 | * overflow on an ANSI-C90 compliant system so the cast needs to ensure |
| 3813 | * that this is not possible. |
| 3814 | */ |
| 3815 | double r = floor(65535*pow((png_int_32)value/65535., |
| 3816 | gamma_val*.00001)+.5); |
| 3817 | return (png_uint_16)r; |
| 3818 | # else |
| 3819 | png_int_32 lg2 = png_log16bit(value); |
| 3820 | png_fixed_point res; |
| 3821 | |
| 3822 | if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0) |
| 3823 | return png_exp16bit(res); |
| 3824 | |
| 3825 | /* Overflow. */ |
| 3826 | value = 0; |
| 3827 | # endif |
| 3828 | } |
| 3829 | |
| 3830 | return (png_uint_16)value; |
| 3831 | } |
| 3832 | #endif /* 16BIT */ |
| 3833 | |
| 3834 | /* This does the right thing based on the bit_depth field of the |
| 3835 | * png_struct, interpreting values as 8-bit or 16-bit. While the result |
| 3836 | * is nominally a 16-bit value if bit depth is 8 then the result is |
| 3837 | * 8-bit (as are the arguments.) |
| 3838 | */ |
| 3839 | png_uint_16 /* PRIVATE */ |
| 3840 | png_gamma_correct(png_structrp png_ptr, unsigned int value, |
| 3841 | png_fixed_point gamma_val) |
| 3842 | { |
| 3843 | if (png_ptr->bit_depth == 8) |
| 3844 | return png_gamma_8bit_correct(value, gamma_val); |
| 3845 | |
| 3846 | #ifdef PNG_16BIT_SUPPORTED |
| 3847 | else |
| 3848 | return png_gamma_16bit_correct(value, gamma_val); |
| 3849 | #else |
| 3850 | /* should not reach this */ |
| 3851 | return 0; |
| 3852 | #endif /* 16BIT */ |
| 3853 | } |
| 3854 | |
| 3855 | #ifdef PNG_16BIT_SUPPORTED |
| 3856 | /* Internal function to build a single 16-bit table - the table consists of |
| 3857 | * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount |
| 3858 | * to shift the input values right (or 16-number_of_signifiant_bits). |
| 3859 | * |
| 3860 | * The caller is responsible for ensuring that the table gets cleaned up on |
| 3861 | * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument |
| 3862 | * should be somewhere that will be cleaned. |
| 3863 | */ |
| 3864 | static void |
| 3865 | png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable, |
| 3866 | PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) |
| 3867 | { |
| 3868 | /* Various values derived from 'shift': */ |
| 3869 | PNG_CONST unsigned int num = 1U << (8U - shift); |
| 3870 | #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3871 | /* CSE the division and work round wacky GCC warnings (see the comments |
| 3872 | * in png_gamma_8bit_correct for where these come from.) |
| 3873 | */ |
| 3874 | PNG_CONST double fmax = 1./(((png_int_32)1 << (16U - shift))-1); |
| 3875 | #endif |
| 3876 | PNG_CONST unsigned int max = (1U << (16U - shift))-1U; |
| 3877 | PNG_CONST unsigned int max_by_2 = 1U << (15U-shift); |
| 3878 | unsigned int i; |
| 3879 | |
| 3880 | png_uint_16pp table = *ptable = |
| 3881 | (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); |
| 3882 | |
| 3883 | for (i = 0; i < num; i++) |
| 3884 | { |
| 3885 | png_uint_16p sub_table = table[i] = |
| 3886 | (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16))); |
| 3887 | |
| 3888 | /* The 'threshold' test is repeated here because it can arise for one of |
| 3889 | * the 16-bit tables even if the others don't hit it. |
| 3890 | */ |
| 3891 | if (png_gamma_significant(gamma_val) != 0) |
| 3892 | { |
| 3893 | /* The old code would overflow at the end and this would cause the |
| 3894 | * 'pow' function to return a result >1, resulting in an |
| 3895 | * arithmetic error. This code follows the spec exactly; ig is |
| 3896 | * the recovered input sample, it always has 8-16 bits. |
| 3897 | * |
| 3898 | * We want input * 65535/max, rounded, the arithmetic fits in 32 |
| 3899 | * bits (unsigned) so long as max <= 32767. |
| 3900 | */ |
| 3901 | unsigned int j; |
| 3902 | for (j = 0; j < 256; j++) |
| 3903 | { |
| 3904 | png_uint_32 ig = (j << (8-shift)) + i; |
| 3905 | # ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED |
| 3906 | /* Inline the 'max' scaling operation: */ |
| 3907 | /* See png_gamma_8bit_correct for why the cast to (int) is |
| 3908 | * required here. |
| 3909 | */ |
| 3910 | double d = floor(65535.*pow(ig*fmax, gamma_val*.00001)+.5); |
| 3911 | sub_table[j] = (png_uint_16)d; |
| 3912 | # else |
| 3913 | if (shift != 0) |
| 3914 | ig = (ig * 65535U + max_by_2)/max; |
| 3915 | |
| 3916 | sub_table[j] = png_gamma_16bit_correct(ig, gamma_val); |
| 3917 | # endif |
| 3918 | } |
| 3919 | } |
| 3920 | else |
| 3921 | { |
| 3922 | /* We must still build a table, but do it the fast way. */ |
| 3923 | unsigned int j; |
| 3924 | |
| 3925 | for (j = 0; j < 256; j++) |
| 3926 | { |
| 3927 | png_uint_32 ig = (j << (8-shift)) + i; |
| 3928 | |
| 3929 | if (shift != 0) |
| 3930 | ig = (ig * 65535U + max_by_2)/max; |
| 3931 | |
| 3932 | sub_table[j] = (png_uint_16)ig; |
| 3933 | } |
| 3934 | } |
| 3935 | } |
| 3936 | } |
| 3937 | |
| 3938 | /* NOTE: this function expects the *inverse* of the overall gamma transformation |
| 3939 | * required. |
| 3940 | */ |
| 3941 | static void |
| 3942 | png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable, |
| 3943 | PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) |
| 3944 | { |
| 3945 | PNG_CONST unsigned int num = 1U << (8U - shift); |
| 3946 | PNG_CONST unsigned int max = (1U << (16U - shift))-1U; |
| 3947 | unsigned int i; |
| 3948 | png_uint_32 last; |
| 3949 | |
| 3950 | png_uint_16pp table = *ptable = |
| 3951 | (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); |
| 3952 | |
| 3953 | /* 'num' is the number of tables and also the number of low bits of low |
| 3954 | * bits of the input 16-bit value used to select a table. Each table is |
| 3955 | * itself indexed by the high 8 bits of the value. |
| 3956 | */ |
| 3957 | for (i = 0; i < num; i++) |
| 3958 | table[i] = (png_uint_16p)png_malloc(png_ptr, |
| 3959 | 256 * (sizeof (png_uint_16))); |
| 3960 | |
| 3961 | /* 'gamma_val' is set to the reciprocal of the value calculated above, so |
| 3962 | * pow(out,g) is an *input* value. 'last' is the last input value set. |
| 3963 | * |
| 3964 | * In the loop 'i' is used to find output values. Since the output is |
| 3965 | * 8-bit there are only 256 possible values. The tables are set up to |
| 3966 | * select the closest possible output value for each input by finding |
| 3967 | * the input value at the boundary between each pair of output values |
| 3968 | * and filling the table up to that boundary with the lower output |
| 3969 | * value. |
| 3970 | * |
| 3971 | * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit |
| 3972 | * values the code below uses a 16-bit value in i; the values start at |
| 3973 | * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last |
| 3974 | * entries are filled with 255). Start i at 128 and fill all 'last' |
| 3975 | * table entries <= 'max' |
| 3976 | */ |
| 3977 | last = 0; |
| 3978 | for (i = 0; i < 255; ++i) /* 8-bit output value */ |
| 3979 | { |
| 3980 | /* Find the corresponding maximum input value */ |
| 3981 | png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */ |
| 3982 | |
| 3983 | /* Find the boundary value in 16 bits: */ |
| 3984 | png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val); |
| 3985 | |
| 3986 | /* Adjust (round) to (16-shift) bits: */ |
| 3987 | bound = (bound * max + 32768U)/65535U + 1U; |
| 3988 | |
| 3989 | while (last < bound) |
| 3990 | { |
| 3991 | table[last & (0xffU >> shift)][last >> (8U - shift)] = out; |
| 3992 | last++; |
| 3993 | } |
| 3994 | } |
| 3995 | |
| 3996 | /* And fill in the final entries. */ |
| 3997 | while (last < (num << 8)) |
| 3998 | { |
| 3999 | table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U; |
| 4000 | last++; |
| 4001 | } |
| 4002 | } |
| 4003 | #endif /* 16BIT */ |
| 4004 | |
| 4005 | /* Build a single 8-bit table: same as the 16-bit case but much simpler (and |
| 4006 | * typically much faster). Note that libpng currently does no sBIT processing |
| 4007 | * (apparently contrary to the spec) so a 256-entry table is always generated. |
| 4008 | */ |
| 4009 | static void |
| 4010 | png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable, |
| 4011 | PNG_CONST png_fixed_point gamma_val) |
| 4012 | { |
| 4013 | unsigned int i; |
| 4014 | png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256); |
| 4015 | |
| 4016 | if (png_gamma_significant(gamma_val) != 0) |
| 4017 | for (i=0; i<256; i++) |
| 4018 | table[i] = png_gamma_8bit_correct(i, gamma_val); |
| 4019 | |
| 4020 | else |
| 4021 | for (i=0; i<256; ++i) |
| 4022 | table[i] = (png_byte)(i & 0xff); |
| 4023 | } |
| 4024 | |
| 4025 | /* Used from png_read_destroy and below to release the memory used by the gamma |
| 4026 | * tables. |
| 4027 | */ |
| 4028 | void /* PRIVATE */ |
| 4029 | png_destroy_gamma_table(png_structrp png_ptr) |
| 4030 | { |
| 4031 | png_free(png_ptr, png_ptr->gamma_table); |
| 4032 | png_ptr->gamma_table = NULL; |
| 4033 | |
| 4034 | #ifdef PNG_16BIT_SUPPORTED |
| 4035 | if (png_ptr->gamma_16_table != NULL) |
| 4036 | { |
| 4037 | int i; |
| 4038 | int istop = (1 << (8 - png_ptr->gamma_shift)); |
| 4039 | for (i = 0; i < istop; i++) |
| 4040 | { |
| 4041 | png_free(png_ptr, png_ptr->gamma_16_table[i]); |
| 4042 | } |
| 4043 | png_free(png_ptr, png_ptr->gamma_16_table); |
| 4044 | png_ptr->gamma_16_table = NULL; |
| 4045 | } |
| 4046 | #endif /* 16BIT */ |
| 4047 | |
| 4048 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ |
| 4049 | defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ |
| 4050 | defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) |
| 4051 | png_free(png_ptr, png_ptr->gamma_from_1); |
| 4052 | png_ptr->gamma_from_1 = NULL; |
| 4053 | png_free(png_ptr, png_ptr->gamma_to_1); |
| 4054 | png_ptr->gamma_to_1 = NULL; |
| 4055 | |
| 4056 | #ifdef PNG_16BIT_SUPPORTED |
| 4057 | if (png_ptr->gamma_16_from_1 != NULL) |
| 4058 | { |
| 4059 | int i; |
| 4060 | int istop = (1 << (8 - png_ptr->gamma_shift)); |
| 4061 | for (i = 0; i < istop; i++) |
| 4062 | { |
| 4063 | png_free(png_ptr, png_ptr->gamma_16_from_1[i]); |
| 4064 | } |
| 4065 | png_free(png_ptr, png_ptr->gamma_16_from_1); |
| 4066 | png_ptr->gamma_16_from_1 = NULL; |
| 4067 | } |
| 4068 | if (png_ptr->gamma_16_to_1 != NULL) |
| 4069 | { |
| 4070 | int i; |
| 4071 | int istop = (1 << (8 - png_ptr->gamma_shift)); |
| 4072 | for (i = 0; i < istop; i++) |
| 4073 | { |
| 4074 | png_free(png_ptr, png_ptr->gamma_16_to_1[i]); |
| 4075 | } |
| 4076 | png_free(png_ptr, png_ptr->gamma_16_to_1); |
| 4077 | png_ptr->gamma_16_to_1 = NULL; |
| 4078 | } |
| 4079 | #endif /* 16BIT */ |
| 4080 | #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ |
| 4081 | } |
| 4082 | |
| 4083 | /* We build the 8- or 16-bit gamma tables here. Note that for 16-bit |
| 4084 | * tables, we don't make a full table if we are reducing to 8-bit in |
| 4085 | * the future. Note also how the gamma_16 tables are segmented so that |
| 4086 | * we don't need to allocate > 64K chunks for a full 16-bit table. |
| 4087 | */ |
| 4088 | void /* PRIVATE */ |
| 4089 | png_build_gamma_table(png_structrp png_ptr, int bit_depth) |
| 4090 | { |
| 4091 | png_debug(1, "in png_build_gamma_table"); |
| 4092 | |
| 4093 | /* Remove any existing table; this copes with multiple calls to |
| 4094 | * png_read_update_info. The warning is because building the gamma tables |
| 4095 | * multiple times is a performance hit - it's harmless but the ability to call |
| 4096 | * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible |
| 4097 | * to warn if the app introduces such a hit. |
| 4098 | */ |
| 4099 | if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL) |
| 4100 | { |
| 4101 | png_warning(png_ptr, "gamma table being rebuilt"); |
| 4102 | png_destroy_gamma_table(png_ptr); |
| 4103 | } |
| 4104 | |
| 4105 | if (bit_depth <= 8) |
| 4106 | { |
| 4107 | png_build_8bit_table(png_ptr, &png_ptr->gamma_table, |
| 4108 | png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, |
| 4109 | png_ptr->screen_gamma) : PNG_FP_1); |
| 4110 | |
| 4111 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ |
| 4112 | defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ |
| 4113 | defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) |
| 4114 | if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0) |
| 4115 | { |
| 4116 | png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1, |
| 4117 | png_reciprocal(png_ptr->colorspace.gamma)); |
| 4118 | |
| 4119 | png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1, |
| 4120 | png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : |
| 4121 | png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); |
| 4122 | } |
| 4123 | #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ |
| 4124 | } |
| 4125 | #ifdef PNG_16BIT_SUPPORTED |
| 4126 | else |
| 4127 | { |
| 4128 | png_byte shift, sig_bit; |
| 4129 | |
| 4130 | if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) |
| 4131 | { |
| 4132 | sig_bit = png_ptr->sig_bit.red; |
| 4133 | |
| 4134 | if (png_ptr->sig_bit.green > sig_bit) |
| 4135 | sig_bit = png_ptr->sig_bit.green; |
| 4136 | |
| 4137 | if (png_ptr->sig_bit.blue > sig_bit) |
| 4138 | sig_bit = png_ptr->sig_bit.blue; |
| 4139 | } |
| 4140 | else |
| 4141 | sig_bit = png_ptr->sig_bit.gray; |
| 4142 | |
| 4143 | /* 16-bit gamma code uses this equation: |
| 4144 | * |
| 4145 | * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8] |
| 4146 | * |
| 4147 | * Where 'iv' is the input color value and 'ov' is the output value - |
| 4148 | * pow(iv, gamma). |
| 4149 | * |
| 4150 | * Thus the gamma table consists of up to 256 256-entry tables. The table |
| 4151 | * is selected by the (8-gamma_shift) most significant of the low 8 bits of |
| 4152 | * the color value then indexed by the upper 8 bits: |
| 4153 | * |
| 4154 | * table[low bits][high 8 bits] |
| 4155 | * |
| 4156 | * So the table 'n' corresponds to all those 'iv' of: |
| 4157 | * |
| 4158 | * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1> |
| 4159 | * |
| 4160 | */ |
| 4161 | if (sig_bit > 0 && sig_bit < 16U) |
| 4162 | /* shift == insignificant bits */ |
| 4163 | shift = (png_byte)((16U - sig_bit) & 0xff); |
| 4164 | |
| 4165 | else |
| 4166 | shift = 0; /* keep all 16 bits */ |
| 4167 | |
| 4168 | if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0) |
| 4169 | { |
| 4170 | /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively |
| 4171 | * the significant bits in the *input* when the output will |
| 4172 | * eventually be 8 bits. By default it is 11. |
| 4173 | */ |
| 4174 | if (shift < (16U - PNG_MAX_GAMMA_8)) |
| 4175 | shift = (16U - PNG_MAX_GAMMA_8); |
| 4176 | } |
| 4177 | |
| 4178 | if (shift > 8U) |
| 4179 | shift = 8U; /* Guarantees at least one table! */ |
| 4180 | |
| 4181 | png_ptr->gamma_shift = shift; |
| 4182 | |
| 4183 | /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now |
| 4184 | * PNG_COMPOSE). This effectively smashed the background calculation for |
| 4185 | * 16-bit output because the 8-bit table assumes the result will be reduced |
| 4186 | * to 8 bits. |
| 4187 | */ |
| 4188 | if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0) |
| 4189 | png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift, |
| 4190 | png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma, |
| 4191 | png_ptr->screen_gamma) : PNG_FP_1); |
| 4192 | |
| 4193 | else |
| 4194 | png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift, |
| 4195 | png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, |
| 4196 | png_ptr->screen_gamma) : PNG_FP_1); |
| 4197 | |
| 4198 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ |
| 4199 | defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ |
| 4200 | defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) |
| 4201 | if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0) |
| 4202 | { |
| 4203 | png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift, |
| 4204 | png_reciprocal(png_ptr->colorspace.gamma)); |
| 4205 | |
| 4206 | /* Notice that the '16 from 1' table should be full precision, however |
| 4207 | * the lookup on this table still uses gamma_shift, so it can't be. |
| 4208 | * TODO: fix this. |
| 4209 | */ |
| 4210 | png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift, |
| 4211 | png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : |
| 4212 | png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); |
| 4213 | } |
| 4214 | #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ |
| 4215 | } |
| 4216 | #endif /* 16BIT */ |
| 4217 | } |
| 4218 | #endif /* READ_GAMMA */ |
| 4219 | |
| 4220 | /* HARDWARE OR SOFTWARE OPTION SUPPORT */ |
| 4221 | #ifdef PNG_SET_OPTION_SUPPORTED |
| 4222 | int PNGAPI |
| 4223 | png_set_option(png_structrp png_ptr, int option, int onoff) |
| 4224 | { |
| 4225 | if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT && |
| 4226 | (option & 1) == 0) |
| 4227 | { |
| 4228 | int mask = 3 << option; |
| 4229 | int setting = (2 + (onoff != 0)) << option; |
| 4230 | int current = png_ptr->options; |
| 4231 | |
| 4232 | png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff); |
| 4233 | |
| 4234 | return (current & mask) >> option; |
| 4235 | } |
| 4236 | |
| 4237 | return PNG_OPTION_INVALID; |
| 4238 | } |
| 4239 | #endif |
| 4240 | |
| 4241 | /* sRGB support */ |
| 4242 | #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ |
| 4243 | defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) |
| 4244 | /* sRGB conversion tables; these are machine generated with the code in |
| 4245 | * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the |
| 4246 | * specification (see the article at http://en.wikipedia.org/wiki/SRGB) |
| 4247 | * is used, not the gamma=1/2.2 approximation use elsewhere in libpng. |
| 4248 | * The sRGB to linear table is exact (to the nearest 16-bit linear fraction). |
| 4249 | * The inverse (linear to sRGB) table has accuracies as follows: |
| 4250 | * |
| 4251 | * For all possible (255*65535+1) input values: |
| 4252 | * |
| 4253 | * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact |
| 4254 | * |
| 4255 | * For the input values corresponding to the 65536 16-bit values: |
| 4256 | * |
| 4257 | * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact |
| 4258 | * |
| 4259 | * In all cases the inexact readings are only off by one. |
| 4260 | */ |
| 4261 | |
| 4262 | #ifdef PNG_SIMPLIFIED_READ_SUPPORTED |
| 4263 | /* The convert-to-sRGB table is only currently required for read. */ |
| 4264 | const png_uint_16 png_sRGB_table[256] = |
| 4265 | { |
| 4266 | 0,20,40,60,80,99,119,139, |
| 4267 | 159,179,199,219,241,264,288,313, |
| 4268 | 340,367,396,427,458,491,526,562, |
| 4269 | 599,637,677,718,761,805,851,898, |
| 4270 | 947,997,1048,1101,1156,1212,1270,1330, |
| 4271 | 1391,1453,1517,1583,1651,1720,1790,1863, |
| 4272 | 1937,2013,2090,2170,2250,2333,2418,2504, |
| 4273 | 2592,2681,2773,2866,2961,3058,3157,3258, |
| 4274 | 3360,3464,3570,3678,3788,3900,4014,4129, |
| 4275 | 4247,4366,4488,4611,4736,4864,4993,5124, |
| 4276 | 5257,5392,5530,5669,5810,5953,6099,6246, |
| 4277 | 6395,6547,6700,6856,7014,7174,7335,7500, |
| 4278 | 7666,7834,8004,8177,8352,8528,8708,8889, |
| 4279 | 9072,9258,9445,9635,9828,10022,10219,10417, |
| 4280 | 10619,10822,11028,11235,11446,11658,11873,12090, |
| 4281 | 12309,12530,12754,12980,13209,13440,13673,13909, |
| 4282 | 14146,14387,14629,14874,15122,15371,15623,15878, |
| 4283 | 16135,16394,16656,16920,17187,17456,17727,18001, |
| 4284 | 18277,18556,18837,19121,19407,19696,19987,20281, |
| 4285 | 20577,20876,21177,21481,21787,22096,22407,22721, |
| 4286 | 23038,23357,23678,24002,24329,24658,24990,25325, |
| 4287 | 25662,26001,26344,26688,27036,27386,27739,28094, |
| 4288 | 28452,28813,29176,29542,29911,30282,30656,31033, |
| 4289 | 31412,31794,32179,32567,32957,33350,33745,34143, |
| 4290 | 34544,34948,35355,35764,36176,36591,37008,37429, |
| 4291 | 37852,38278,38706,39138,39572,40009,40449,40891, |
| 4292 | 41337,41785,42236,42690,43147,43606,44069,44534, |
| 4293 | 45002,45473,45947,46423,46903,47385,47871,48359, |
| 4294 | 48850,49344,49841,50341,50844,51349,51858,52369, |
| 4295 | 52884,53401,53921,54445,54971,55500,56032,56567, |
| 4296 | 57105,57646,58190,58737,59287,59840,60396,60955, |
| 4297 | 61517,62082,62650,63221,63795,64372,64952,65535 |
| 4298 | }; |
| 4299 | #endif /* SIMPLIFIED_READ */ |
| 4300 | |
| 4301 | /* The base/delta tables are required for both read and write (but currently |
| 4302 | * only the simplified versions.) |
| 4303 | */ |
| 4304 | const png_uint_16 png_sRGB_base[512] = |
| 4305 | { |
| 4306 | 128,1782,3383,4644,5675,6564,7357,8074, |
| 4307 | 8732,9346,9921,10463,10977,11466,11935,12384, |
| 4308 | 12816,13233,13634,14024,14402,14769,15125,15473, |
| 4309 | 15812,16142,16466,16781,17090,17393,17690,17981, |
| 4310 | 18266,18546,18822,19093,19359,19621,19879,20133, |
| 4311 | 20383,20630,20873,21113,21349,21583,21813,22041, |
| 4312 | 22265,22487,22707,22923,23138,23350,23559,23767, |
| 4313 | 23972,24175,24376,24575,24772,24967,25160,25352, |
| 4314 | 25542,25730,25916,26101,26284,26465,26645,26823, |
| 4315 | 27000,27176,27350,27523,27695,27865,28034,28201, |
| 4316 | 28368,28533,28697,28860,29021,29182,29341,29500, |
| 4317 | 29657,29813,29969,30123,30276,30429,30580,30730, |
| 4318 | 30880,31028,31176,31323,31469,31614,31758,31902, |
| 4319 | 32045,32186,32327,32468,32607,32746,32884,33021, |
| 4320 | 33158,33294,33429,33564,33697,33831,33963,34095, |
| 4321 | 34226,34357,34486,34616,34744,34873,35000,35127, |
| 4322 | 35253,35379,35504,35629,35753,35876,35999,36122, |
| 4323 | 36244,36365,36486,36606,36726,36845,36964,37083, |
| 4324 | 37201,37318,37435,37551,37668,37783,37898,38013, |
| 4325 | 38127,38241,38354,38467,38580,38692,38803,38915, |
| 4326 | 39026,39136,39246,39356,39465,39574,39682,39790, |
| 4327 | 39898,40005,40112,40219,40325,40431,40537,40642, |
| 4328 | 40747,40851,40955,41059,41163,41266,41369,41471, |
| 4329 | 41573,41675,41777,41878,41979,42079,42179,42279, |
| 4330 | 42379,42478,42577,42676,42775,42873,42971,43068, |
| 4331 | 43165,43262,43359,43456,43552,43648,43743,43839, |
| 4332 | 43934,44028,44123,44217,44311,44405,44499,44592, |
| 4333 | 44685,44778,44870,44962,45054,45146,45238,45329, |
| 4334 | 45420,45511,45601,45692,45782,45872,45961,46051, |
| 4335 | 46140,46229,46318,46406,46494,46583,46670,46758, |
| 4336 | 46846,46933,47020,47107,47193,47280,47366,47452, |
| 4337 | 47538,47623,47709,47794,47879,47964,48048,48133, |
| 4338 | 48217,48301,48385,48468,48552,48635,48718,48801, |
| 4339 | 48884,48966,49048,49131,49213,49294,49376,49458, |
| 4340 | 49539,49620,49701,49782,49862,49943,50023,50103, |
| 4341 | 50183,50263,50342,50422,50501,50580,50659,50738, |
| 4342 | 50816,50895,50973,51051,51129,51207,51285,51362, |
| 4343 | 51439,51517,51594,51671,51747,51824,51900,51977, |
| 4344 | 52053,52129,52205,52280,52356,52432,52507,52582, |
| 4345 | 52657,52732,52807,52881,52956,53030,53104,53178, |
| 4346 | 53252,53326,53400,53473,53546,53620,53693,53766, |
| 4347 | 53839,53911,53984,54056,54129,54201,54273,54345, |
| 4348 | 54417,54489,54560,54632,54703,54774,54845,54916, |
| 4349 | 54987,55058,55129,55199,55269,55340,55410,55480, |
| 4350 | 55550,55620,55689,55759,55828,55898,55967,56036, |
| 4351 | 56105,56174,56243,56311,56380,56448,56517,56585, |
| 4352 | 56653,56721,56789,56857,56924,56992,57059,57127, |
| 4353 | 57194,57261,57328,57395,57462,57529,57595,57662, |
| 4354 | 57728,57795,57861,57927,57993,58059,58125,58191, |
| 4355 | 58256,58322,58387,58453,58518,58583,58648,58713, |
| 4356 | 58778,58843,58908,58972,59037,59101,59165,59230, |
| 4357 | 59294,59358,59422,59486,59549,59613,59677,59740, |
| 4358 | 59804,59867,59930,59993,60056,60119,60182,60245, |
| 4359 | 60308,60370,60433,60495,60558,60620,60682,60744, |
| 4360 | 60806,60868,60930,60992,61054,61115,61177,61238, |
| 4361 | 61300,61361,61422,61483,61544,61605,61666,61727, |
| 4362 | 61788,61848,61909,61969,62030,62090,62150,62211, |
| 4363 | 62271,62331,62391,62450,62510,62570,62630,62689, |
| 4364 | 62749,62808,62867,62927,62986,63045,63104,63163, |
| 4365 | 63222,63281,63340,63398,63457,63515,63574,63632, |
| 4366 | 63691,63749,63807,63865,63923,63981,64039,64097, |
| 4367 | 64155,64212,64270,64328,64385,64443,64500,64557, |
| 4368 | 64614,64672,64729,64786,64843,64900,64956,65013, |
| 4369 | 65070,65126,65183,65239,65296,65352,65409,65465 |
| 4370 | }; |
| 4371 | |
| 4372 | const png_byte png_sRGB_delta[512] = |
| 4373 | { |
| 4374 | 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54, |
| 4375 | 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36, |
| 4376 | 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28, |
| 4377 | 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24, |
| 4378 | 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21, |
| 4379 | 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19, |
| 4380 | 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17, |
| 4381 | 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16, |
| 4382 | 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15, |
| 4383 | 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14, |
| 4384 | 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13, |
| 4385 | 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12, |
| 4386 | 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12, |
| 4387 | 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11, |
| 4388 | 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, |
| 4389 | 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, |
| 4390 | 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, |
| 4391 | 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, |
| 4392 | 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, |
| 4393 | 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, |
| 4394 | 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, |
| 4395 | 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, |
| 4396 | 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, |
| 4397 | 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, |
| 4398 | 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, |
| 4399 | 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, |
| 4400 | 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, |
| 4401 | 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, |
| 4402 | 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7, |
| 4403 | 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
| 4404 | 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
| 4405 | 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 |
| 4406 | }; |
| 4407 | #endif /* SIMPLIFIED READ/WRITE sRGB support */ |
| 4408 | |
| 4409 | /* SIMPLIFIED READ/WRITE SUPPORT */ |
| 4410 | #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ |
| 4411 | defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) |
| 4412 | static int |
| 4413 | png_image_free_function(png_voidp argument) |
| 4414 | { |
| 4415 | png_imagep image = png_voidcast(png_imagep, argument); |
| 4416 | png_controlp cp = image->opaque; |
| 4417 | png_control c; |
| 4418 | |
| 4419 | /* Double check that we have a png_ptr - it should be impossible to get here |
| 4420 | * without one. |
| 4421 | */ |
| 4422 | if (cp->png_ptr == NULL) |
| 4423 | return 0; |
| 4424 | |
| 4425 | /* First free any data held in the control structure. */ |
| 4426 | # ifdef PNG_STDIO_SUPPORTED |
| 4427 | if (cp->owned_file != 0) |
| 4428 | { |
| 4429 | FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr); |
| 4430 | cp->owned_file = 0; |
| 4431 | |
| 4432 | /* Ignore errors here. */ |
| 4433 | if (fp != NULL) |
| 4434 | { |
| 4435 | cp->png_ptr->io_ptr = NULL; |
| 4436 | (void)fclose(fp); |
| 4437 | } |
| 4438 | } |
| 4439 | # endif |
| 4440 | |
| 4441 | /* Copy the control structure so that the original, allocated, version can be |
| 4442 | * safely freed. Notice that a png_error here stops the remainder of the |
| 4443 | * cleanup, but this is probably fine because that would indicate bad memory |
| 4444 | * problems anyway. |
| 4445 | */ |
| 4446 | c = *cp; |
| 4447 | image->opaque = &c; |
| 4448 | png_free(c.png_ptr, cp); |
| 4449 | |
| 4450 | /* Then the structures, calling the correct API. */ |
| 4451 | if (c.for_write != 0) |
| 4452 | { |
| 4453 | # ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED |
| 4454 | png_destroy_write_struct(&c.png_ptr, &c.info_ptr); |
| 4455 | # else |
| 4456 | png_error(c.png_ptr, "simplified write not supported"); |
| 4457 | # endif |
| 4458 | } |
| 4459 | else |
| 4460 | { |
| 4461 | # ifdef PNG_SIMPLIFIED_READ_SUPPORTED |
| 4462 | png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL); |
| 4463 | # else |
| 4464 | png_error(c.png_ptr, "simplified read not supported"); |
| 4465 | # endif |
| 4466 | } |
| 4467 | |
| 4468 | /* Success. */ |
| 4469 | return 1; |
| 4470 | } |
| 4471 | |
| 4472 | void PNGAPI |
| 4473 | png_image_free(png_imagep image) |
| 4474 | { |
| 4475 | /* Safely call the real function, but only if doing so is safe at this point |
| 4476 | * (if not inside an error handling context). Otherwise assume |
| 4477 | * png_safe_execute will call this API after the return. |
| 4478 | */ |
| 4479 | if (image != NULL && image->opaque != NULL && |
| 4480 | image->opaque->error_buf == NULL) |
| 4481 | { |
| 4482 | /* Ignore errors here: */ |
| 4483 | (void)png_safe_execute(image, png_image_free_function, image); |
| 4484 | image->opaque = NULL; |
| 4485 | } |
| 4486 | } |
| 4487 | |
| 4488 | int /* PRIVATE */ |
| 4489 | png_image_error(png_imagep image, png_const_charp error_message) |
| 4490 | { |
| 4491 | /* Utility to log an error. */ |
| 4492 | png_safecat(image->message, (sizeof image->message), 0, error_message); |
| 4493 | image->warning_or_error |= PNG_IMAGE_ERROR; |
| 4494 | png_image_free(image); |
| 4495 | return 0; |
| 4496 | } |
| 4497 | |
| 4498 | #endif /* SIMPLIFIED READ/WRITE */ |
| 4499 | #endif /* READ || WRITE */ |