1 // Copyright 2012 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // main entry for the decoder 11 // 12 // Authors: Vikas Arora (vikaas.arora (at) gmail.com) 13 // Jyrki Alakuijala (jyrki (at) google.com) 14 15 #include <stdlib.h> 16 17 #include "./alphai_dec.h" 18 #include "./vp8li_dec.h" 19 #include "../dsp/dsp.h" 20 #include "../dsp/lossless.h" 21 #include "../dsp/lossless_common.h" 22 #include "../dsp/yuv.h" 23 #include "../utils/endian_inl_utils.h" 24 #include "../utils/huffman_utils.h" 25 #include "../utils/utils.h" 26 27 #define NUM_ARGB_CACHE_ROWS 16 28 29 static const int kCodeLengthLiterals = 16; 30 static const int kCodeLengthRepeatCode = 16; 31 static const int kCodeLengthExtraBits[3] = { 2, 3, 7 }; 32 static const int kCodeLengthRepeatOffsets[3] = { 3, 3, 11 }; 33 34 // ----------------------------------------------------------------------------- 35 // Five Huffman codes are used at each meta code: 36 // 1. green + length prefix codes + color cache codes, 37 // 2. alpha, 38 // 3. red, 39 // 4. blue, and, 40 // 5. distance prefix codes. 41 typedef enum { 42 GREEN = 0, 43 RED = 1, 44 BLUE = 2, 45 ALPHA = 3, 46 DIST = 4 47 } HuffIndex; 48 49 static const uint16_t kAlphabetSize[HUFFMAN_CODES_PER_META_CODE] = { 50 NUM_LITERAL_CODES + NUM_LENGTH_CODES, 51 NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES, 52 NUM_DISTANCE_CODES 53 }; 54 55 static const uint8_t kLiteralMap[HUFFMAN_CODES_PER_META_CODE] = { 56 0, 1, 1, 1, 0 57 }; 58 59 #define NUM_CODE_LENGTH_CODES 19 60 static const uint8_t kCodeLengthCodeOrder[NUM_CODE_LENGTH_CODES] = { 61 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 62 }; 63 64 #define CODE_TO_PLANE_CODES 120 65 static const uint8_t kCodeToPlane[CODE_TO_PLANE_CODES] = { 66 0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a, 67 0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a, 68 0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b, 69 0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03, 70 0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c, 71 0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e, 72 0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b, 73 0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f, 74 0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b, 75 0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41, 76 0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f, 77 0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70 78 }; 79 80 // Memory needed for lookup tables of one Huffman tree group. Red, blue, alpha 81 // and distance alphabets are constant (256 for red, blue and alpha, 40 for 82 // distance) and lookup table sizes for them in worst case are 630 and 410 83 // respectively. Size of green alphabet depends on color cache size and is equal 84 // to 256 (green component values) + 24 (length prefix values) 85 // + color_cache_size (between 0 and 2048). 86 // All values computed for 8-bit first level lookup with Mark Adler's tool: 87 // http://www.hdfgroup.org/ftp/lib-external/zlib/zlib-1.2.5/examples/enough.c 88 #define FIXED_TABLE_SIZE (630 * 3 + 410) 89 static const int kTableSize[12] = { 90 FIXED_TABLE_SIZE + 654, 91 FIXED_TABLE_SIZE + 656, 92 FIXED_TABLE_SIZE + 658, 93 FIXED_TABLE_SIZE + 662, 94 FIXED_TABLE_SIZE + 670, 95 FIXED_TABLE_SIZE + 686, 96 FIXED_TABLE_SIZE + 718, 97 FIXED_TABLE_SIZE + 782, 98 FIXED_TABLE_SIZE + 912, 99 FIXED_TABLE_SIZE + 1168, 100 FIXED_TABLE_SIZE + 1680, 101 FIXED_TABLE_SIZE + 2704 102 }; 103 104 static int DecodeImageStream(int xsize, int ysize, 105 int is_level0, 106 VP8LDecoder* const dec, 107 uint32_t** const decoded_data); 108 109 //------------------------------------------------------------------------------ 110 111 int VP8LCheckSignature(const uint8_t* const data, size_t size) { 112 return (size >= VP8L_FRAME_HEADER_SIZE && 113 data[0] == VP8L_MAGIC_BYTE && 114 (data[4] >> 5) == 0); // version 115 } 116 117 static int ReadImageInfo(VP8LBitReader* const br, 118 int* const width, int* const height, 119 int* const has_alpha) { 120 if (VP8LReadBits(br, 8) != VP8L_MAGIC_BYTE) return 0; 121 *width = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1; 122 *height = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1; 123 *has_alpha = VP8LReadBits(br, 1); 124 if (VP8LReadBits(br, VP8L_VERSION_BITS) != 0) return 0; 125 return !br->eos_; 126 } 127 128 int VP8LGetInfo(const uint8_t* data, size_t data_size, 129 int* const width, int* const height, int* const has_alpha) { 130 if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) { 131 return 0; // not enough data 132 } else if (!VP8LCheckSignature(data, data_size)) { 133 return 0; // bad signature 134 } else { 135 int w, h, a; 136 VP8LBitReader br; 137 VP8LInitBitReader(&br, data, data_size); 138 if (!ReadImageInfo(&br, &w, &h, &a)) { 139 return 0; 140 } 141 if (width != NULL) *width = w; 142 if (height != NULL) *height = h; 143 if (has_alpha != NULL) *has_alpha = a; 144 return 1; 145 } 146 } 147 148 //------------------------------------------------------------------------------ 149 150 static WEBP_INLINE int GetCopyDistance(int distance_symbol, 151 VP8LBitReader* const br) { 152 int extra_bits, offset; 153 if (distance_symbol < 4) { 154 return distance_symbol + 1; 155 } 156 extra_bits = (distance_symbol - 2) >> 1; 157 offset = (2 + (distance_symbol & 1)) << extra_bits; 158 return offset + VP8LReadBits(br, extra_bits) + 1; 159 } 160 161 static WEBP_INLINE int GetCopyLength(int length_symbol, 162 VP8LBitReader* const br) { 163 // Length and distance prefixes are encoded the same way. 164 return GetCopyDistance(length_symbol, br); 165 } 166 167 static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) { 168 if (plane_code > CODE_TO_PLANE_CODES) { 169 return plane_code - CODE_TO_PLANE_CODES; 170 } else { 171 const int dist_code = kCodeToPlane[plane_code - 1]; 172 const int yoffset = dist_code >> 4; 173 const int xoffset = 8 - (dist_code & 0xf); 174 const int dist = yoffset * xsize + xoffset; 175 return (dist >= 1) ? dist : 1; // dist<1 can happen if xsize is very small 176 } 177 } 178 179 //------------------------------------------------------------------------------ 180 // Decodes the next Huffman code from bit-stream. 181 // FillBitWindow(br) needs to be called at minimum every second call 182 // to ReadSymbol, in order to pre-fetch enough bits. 183 static WEBP_INLINE int ReadSymbol(const HuffmanCode* table, 184 VP8LBitReader* const br) { 185 int nbits; 186 uint32_t val = VP8LPrefetchBits(br); 187 table += val & HUFFMAN_TABLE_MASK; 188 nbits = table->bits - HUFFMAN_TABLE_BITS; 189 if (nbits > 0) { 190 VP8LSetBitPos(br, br->bit_pos_ + HUFFMAN_TABLE_BITS); 191 val = VP8LPrefetchBits(br); 192 table += table->value; 193 table += val & ((1 << nbits) - 1); 194 } 195 VP8LSetBitPos(br, br->bit_pos_ + table->bits); 196 return table->value; 197 } 198 199 // Reads packed symbol depending on GREEN channel 200 #define BITS_SPECIAL_MARKER 0x100 // something large enough (and a bit-mask) 201 #define PACKED_NON_LITERAL_CODE 0 // must be < NUM_LITERAL_CODES 202 static WEBP_INLINE int ReadPackedSymbols(const HTreeGroup* group, 203 VP8LBitReader* const br, 204 uint32_t* const dst) { 205 const uint32_t val = VP8LPrefetchBits(br) & (HUFFMAN_PACKED_TABLE_SIZE - 1); 206 const HuffmanCode32 code = group->packed_table[val]; 207 assert(group->use_packed_table); 208 if (code.bits < BITS_SPECIAL_MARKER) { 209 VP8LSetBitPos(br, br->bit_pos_ + code.bits); 210 *dst = code.value; 211 return PACKED_NON_LITERAL_CODE; 212 } else { 213 VP8LSetBitPos(br, br->bit_pos_ + code.bits - BITS_SPECIAL_MARKER); 214 assert(code.value >= NUM_LITERAL_CODES); 215 return code.value; 216 } 217 } 218 219 static int AccumulateHCode(HuffmanCode hcode, int shift, 220 HuffmanCode32* const huff) { 221 huff->bits += hcode.bits; 222 huff->value |= (uint32_t)hcode.value << shift; 223 assert(huff->bits <= HUFFMAN_TABLE_BITS); 224 return hcode.bits; 225 } 226 227 static void BuildPackedTable(HTreeGroup* const htree_group) { 228 uint32_t code; 229 for (code = 0; code < HUFFMAN_PACKED_TABLE_SIZE; ++code) { 230 uint32_t bits = code; 231 HuffmanCode32* const huff = &htree_group->packed_table[bits]; 232 HuffmanCode hcode = htree_group->htrees[GREEN][bits]; 233 if (hcode.value >= NUM_LITERAL_CODES) { 234 huff->bits = hcode.bits + BITS_SPECIAL_MARKER; 235 huff->value = hcode.value; 236 } else { 237 huff->bits = 0; 238 huff->value = 0; 239 bits >>= AccumulateHCode(hcode, 8, huff); 240 bits >>= AccumulateHCode(htree_group->htrees[RED][bits], 16, huff); 241 bits >>= AccumulateHCode(htree_group->htrees[BLUE][bits], 0, huff); 242 bits >>= AccumulateHCode(htree_group->htrees[ALPHA][bits], 24, huff); 243 (void)bits; 244 } 245 } 246 } 247 248 static int ReadHuffmanCodeLengths( 249 VP8LDecoder* const dec, const int* const code_length_code_lengths, 250 int num_symbols, int* const code_lengths) { 251 int ok = 0; 252 VP8LBitReader* const br = &dec->br_; 253 int symbol; 254 int max_symbol; 255 int prev_code_len = DEFAULT_CODE_LENGTH; 256 HuffmanCode table[1 << LENGTHS_TABLE_BITS]; 257 258 if (!VP8LBuildHuffmanTable(table, LENGTHS_TABLE_BITS, 259 code_length_code_lengths, 260 NUM_CODE_LENGTH_CODES)) { 261 goto End; 262 } 263 264 if (VP8LReadBits(br, 1)) { // use length 265 const int length_nbits = 2 + 2 * VP8LReadBits(br, 3); 266 max_symbol = 2 + VP8LReadBits(br, length_nbits); 267 if (max_symbol > num_symbols) { 268 goto End; 269 } 270 } else { 271 max_symbol = num_symbols; 272 } 273 274 symbol = 0; 275 while (symbol < num_symbols) { 276 const HuffmanCode* p; 277 int code_len; 278 if (max_symbol-- == 0) break; 279 VP8LFillBitWindow(br); 280 p = &table[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK]; 281 VP8LSetBitPos(br, br->bit_pos_ + p->bits); 282 code_len = p->value; 283 if (code_len < kCodeLengthLiterals) { 284 code_lengths[symbol++] = code_len; 285 if (code_len != 0) prev_code_len = code_len; 286 } else { 287 const int use_prev = (code_len == kCodeLengthRepeatCode); 288 const int slot = code_len - kCodeLengthLiterals; 289 const int extra_bits = kCodeLengthExtraBits[slot]; 290 const int repeat_offset = kCodeLengthRepeatOffsets[slot]; 291 int repeat = VP8LReadBits(br, extra_bits) + repeat_offset; 292 if (symbol + repeat > num_symbols) { 293 goto End; 294 } else { 295 const int length = use_prev ? prev_code_len : 0; 296 while (repeat-- > 0) code_lengths[symbol++] = length; 297 } 298 } 299 } 300 ok = 1; 301 302 End: 303 if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 304 return ok; 305 } 306 307 // 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman 308 // tree. 309 static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec, 310 int* const code_lengths, HuffmanCode* const table) { 311 int ok = 0; 312 int size = 0; 313 VP8LBitReader* const br = &dec->br_; 314 const int simple_code = VP8LReadBits(br, 1); 315 316 memset(code_lengths, 0, alphabet_size * sizeof(*code_lengths)); 317 318 if (simple_code) { // Read symbols, codes & code lengths directly. 319 const int num_symbols = VP8LReadBits(br, 1) + 1; 320 const int first_symbol_len_code = VP8LReadBits(br, 1); 321 // The first code is either 1 bit or 8 bit code. 322 int symbol = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8); 323 code_lengths[symbol] = 1; 324 // The second code (if present), is always 8 bit long. 325 if (num_symbols == 2) { 326 symbol = VP8LReadBits(br, 8); 327 code_lengths[symbol] = 1; 328 } 329 ok = 1; 330 } else { // Decode Huffman-coded code lengths. 331 int i; 332 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 }; 333 const int num_codes = VP8LReadBits(br, 4) + 4; 334 if (num_codes > NUM_CODE_LENGTH_CODES) { 335 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 336 return 0; 337 } 338 339 for (i = 0; i < num_codes; ++i) { 340 code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3); 341 } 342 ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size, 343 code_lengths); 344 } 345 346 ok = ok && !br->eos_; 347 if (ok) { 348 size = VP8LBuildHuffmanTable(table, HUFFMAN_TABLE_BITS, 349 code_lengths, alphabet_size); 350 } 351 if (!ok || size == 0) { 352 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 353 return 0; 354 } 355 return size; 356 } 357 358 static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, 359 int color_cache_bits, int allow_recursion) { 360 int i, j; 361 VP8LBitReader* const br = &dec->br_; 362 VP8LMetadata* const hdr = &dec->hdr_; 363 uint32_t* huffman_image = NULL; 364 HTreeGroup* htree_groups = NULL; 365 HuffmanCode* huffman_tables = NULL; 366 HuffmanCode* next = NULL; 367 int num_htree_groups = 1; 368 int max_alphabet_size = 0; 369 int* code_lengths = NULL; 370 const int table_size = kTableSize[color_cache_bits]; 371 372 if (allow_recursion && VP8LReadBits(br, 1)) { 373 // use meta Huffman codes. 374 const int huffman_precision = VP8LReadBits(br, 3) + 2; 375 const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision); 376 const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision); 377 const int huffman_pixs = huffman_xsize * huffman_ysize; 378 if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec, 379 &huffman_image)) { 380 goto Error; 381 } 382 hdr->huffman_subsample_bits_ = huffman_precision; 383 for (i = 0; i < huffman_pixs; ++i) { 384 // The huffman data is stored in red and green bytes. 385 const int group = (huffman_image[i] >> 8) & 0xffff; 386 huffman_image[i] = group; 387 if (group >= num_htree_groups) { 388 num_htree_groups = group + 1; 389 } 390 } 391 } 392 393 if (br->eos_) goto Error; 394 395 // Find maximum alphabet size for the htree group. 396 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { 397 int alphabet_size = kAlphabetSize[j]; 398 if (j == 0 && color_cache_bits > 0) { 399 alphabet_size += 1 << color_cache_bits; 400 } 401 if (max_alphabet_size < alphabet_size) { 402 max_alphabet_size = alphabet_size; 403 } 404 } 405 406 huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size, 407 sizeof(*huffman_tables)); 408 htree_groups = VP8LHtreeGroupsNew(num_htree_groups); 409 code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size, 410 sizeof(*code_lengths)); 411 412 if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) { 413 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 414 goto Error; 415 } 416 417 next = huffman_tables; 418 for (i = 0; i < num_htree_groups; ++i) { 419 HTreeGroup* const htree_group = &htree_groups[i]; 420 HuffmanCode** const htrees = htree_group->htrees; 421 int size; 422 int total_size = 0; 423 int is_trivial_literal = 1; 424 int max_bits = 0; 425 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { 426 int alphabet_size = kAlphabetSize[j]; 427 htrees[j] = next; 428 if (j == 0 && color_cache_bits > 0) { 429 alphabet_size += 1 << color_cache_bits; 430 } 431 size = ReadHuffmanCode(alphabet_size, dec, code_lengths, next); 432 if (size == 0) { 433 goto Error; 434 } 435 if (is_trivial_literal && kLiteralMap[j] == 1) { 436 is_trivial_literal = (next->bits == 0); 437 } 438 total_size += next->bits; 439 next += size; 440 if (j <= ALPHA) { 441 int local_max_bits = code_lengths[0]; 442 int k; 443 for (k = 1; k < alphabet_size; ++k) { 444 if (code_lengths[k] > local_max_bits) { 445 local_max_bits = code_lengths[k]; 446 } 447 } 448 max_bits += local_max_bits; 449 } 450 } 451 htree_group->is_trivial_literal = is_trivial_literal; 452 htree_group->is_trivial_code = 0; 453 if (is_trivial_literal) { 454 const int red = htrees[RED][0].value; 455 const int blue = htrees[BLUE][0].value; 456 const int alpha = htrees[ALPHA][0].value; 457 htree_group->literal_arb = 458 ((uint32_t)alpha << 24) | (red << 16) | blue; 459 if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) { 460 htree_group->is_trivial_code = 1; 461 htree_group->literal_arb |= htrees[GREEN][0].value << 8; 462 } 463 } 464 htree_group->use_packed_table = !htree_group->is_trivial_code && 465 (max_bits < HUFFMAN_PACKED_BITS); 466 if (htree_group->use_packed_table) BuildPackedTable(htree_group); 467 } 468 WebPSafeFree(code_lengths); 469 470 // All OK. Finalize pointers and return. 471 hdr->huffman_image_ = huffman_image; 472 hdr->num_htree_groups_ = num_htree_groups; 473 hdr->htree_groups_ = htree_groups; 474 hdr->huffman_tables_ = huffman_tables; 475 return 1; 476 477 Error: 478 WebPSafeFree(code_lengths); 479 WebPSafeFree(huffman_image); 480 WebPSafeFree(huffman_tables); 481 VP8LHtreeGroupsFree(htree_groups); 482 return 0; 483 } 484 485 //------------------------------------------------------------------------------ 486 // Scaling. 487 488 static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) { 489 const int num_channels = 4; 490 const int in_width = io->mb_w; 491 const int out_width = io->scaled_width; 492 const int in_height = io->mb_h; 493 const int out_height = io->scaled_height; 494 const uint64_t work_size = 2 * num_channels * (uint64_t)out_width; 495 rescaler_t* work; // Rescaler work area. 496 const uint64_t scaled_data_size = (uint64_t)out_width; 497 uint32_t* scaled_data; // Temporary storage for scaled BGRA data. 498 const uint64_t memory_size = sizeof(*dec->rescaler) + 499 work_size * sizeof(*work) + 500 scaled_data_size * sizeof(*scaled_data); 501 uint8_t* memory = (uint8_t*)WebPSafeMalloc(memory_size, sizeof(*memory)); 502 if (memory == NULL) { 503 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 504 return 0; 505 } 506 assert(dec->rescaler_memory == NULL); 507 dec->rescaler_memory = memory; 508 509 dec->rescaler = (WebPRescaler*)memory; 510 memory += sizeof(*dec->rescaler); 511 work = (rescaler_t*)memory; 512 memory += work_size * sizeof(*work); 513 scaled_data = (uint32_t*)memory; 514 515 WebPRescalerInit(dec->rescaler, in_width, in_height, (uint8_t*)scaled_data, 516 out_width, out_height, 0, num_channels, work); 517 return 1; 518 } 519 520 //------------------------------------------------------------------------------ 521 // Export to ARGB 522 523 // We have special "export" function since we need to convert from BGRA 524 static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace, 525 int rgba_stride, uint8_t* const rgba) { 526 uint32_t* const src = (uint32_t*)rescaler->dst; 527 const int dst_width = rescaler->dst_width; 528 int num_lines_out = 0; 529 while (WebPRescalerHasPendingOutput(rescaler)) { 530 uint8_t* const dst = rgba + num_lines_out * rgba_stride; 531 WebPRescalerExportRow(rescaler); 532 WebPMultARGBRow(src, dst_width, 1); 533 VP8LConvertFromBGRA(src, dst_width, colorspace, dst); 534 ++num_lines_out; 535 } 536 return num_lines_out; 537 } 538 539 // Emit scaled rows. 540 static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec, 541 uint8_t* in, int in_stride, int mb_h, 542 uint8_t* const out, int out_stride) { 543 const WEBP_CSP_MODE colorspace = dec->output_->colorspace; 544 int num_lines_in = 0; 545 int num_lines_out = 0; 546 while (num_lines_in < mb_h) { 547 uint8_t* const row_in = in + num_lines_in * in_stride; 548 uint8_t* const row_out = out + num_lines_out * out_stride; 549 const int lines_left = mb_h - num_lines_in; 550 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left); 551 int lines_imported; 552 assert(needed_lines > 0 && needed_lines <= lines_left); 553 WebPMultARGBRows(row_in, in_stride, 554 dec->rescaler->src_width, needed_lines, 0); 555 lines_imported = 556 WebPRescalerImport(dec->rescaler, lines_left, row_in, in_stride); 557 assert(lines_imported == needed_lines); 558 num_lines_in += lines_imported; 559 num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out); 560 } 561 return num_lines_out; 562 } 563 564 // Emit rows without any scaling. 565 static int EmitRows(WEBP_CSP_MODE colorspace, 566 const uint8_t* row_in, int in_stride, 567 int mb_w, int mb_h, 568 uint8_t* const out, int out_stride) { 569 int lines = mb_h; 570 uint8_t* row_out = out; 571 while (lines-- > 0) { 572 VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out); 573 row_in += in_stride; 574 row_out += out_stride; 575 } 576 return mb_h; // Num rows out == num rows in. 577 } 578 579 //------------------------------------------------------------------------------ 580 // Export to YUVA 581 582 static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos, 583 const WebPDecBuffer* const output) { 584 const WebPYUVABuffer* const buf = &output->u.YUVA; 585 586 // first, the luma plane 587 WebPConvertARGBToY(src, buf->y + y_pos * buf->y_stride, width); 588 589 // then U/V planes 590 { 591 uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride; 592 uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride; 593 // even lines: store values 594 // odd lines: average with previous values 595 WebPConvertARGBToUV(src, u, v, width, !(y_pos & 1)); 596 } 597 // Lastly, store alpha if needed. 598 if (buf->a != NULL) { 599 uint8_t* const a = buf->a + y_pos * buf->a_stride; 600 #if defined(WORDS_BIGENDIAN) 601 WebPExtractAlpha((uint8_t*)src + 0, 0, width, 1, a, 0); 602 #else 603 WebPExtractAlpha((uint8_t*)src + 3, 0, width, 1, a, 0); 604 #endif 605 } 606 } 607 608 static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) { 609 WebPRescaler* const rescaler = dec->rescaler; 610 uint32_t* const src = (uint32_t*)rescaler->dst; 611 const int dst_width = rescaler->dst_width; 612 int num_lines_out = 0; 613 while (WebPRescalerHasPendingOutput(rescaler)) { 614 WebPRescalerExportRow(rescaler); 615 WebPMultARGBRow(src, dst_width, 1); 616 ConvertToYUVA(src, dst_width, y_pos, dec->output_); 617 ++y_pos; 618 ++num_lines_out; 619 } 620 return num_lines_out; 621 } 622 623 static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec, 624 uint8_t* in, int in_stride, int mb_h) { 625 int num_lines_in = 0; 626 int y_pos = dec->last_out_row_; 627 while (num_lines_in < mb_h) { 628 const int lines_left = mb_h - num_lines_in; 629 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left); 630 int lines_imported; 631 WebPMultARGBRows(in, in_stride, dec->rescaler->src_width, needed_lines, 0); 632 lines_imported = 633 WebPRescalerImport(dec->rescaler, lines_left, in, in_stride); 634 assert(lines_imported == needed_lines); 635 num_lines_in += lines_imported; 636 in += needed_lines * in_stride; 637 y_pos += ExportYUVA(dec, y_pos); 638 } 639 return y_pos; 640 } 641 642 static int EmitRowsYUVA(const VP8LDecoder* const dec, 643 const uint8_t* in, int in_stride, 644 int mb_w, int num_rows) { 645 int y_pos = dec->last_out_row_; 646 while (num_rows-- > 0) { 647 ConvertToYUVA((const uint32_t*)in, mb_w, y_pos, dec->output_); 648 in += in_stride; 649 ++y_pos; 650 } 651 return y_pos; 652 } 653 654 //------------------------------------------------------------------------------ 655 // Cropping. 656 657 // Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and 658 // crop options. Also updates the input data pointer, so that it points to the 659 // start of the cropped window. Note that pixels are in ARGB format even if 660 // 'in_data' is uint8_t*. 661 // Returns true if the crop window is not empty. 662 static int SetCropWindow(VP8Io* const io, int y_start, int y_end, 663 uint8_t** const in_data, int pixel_stride) { 664 assert(y_start < y_end); 665 assert(io->crop_left < io->crop_right); 666 if (y_end > io->crop_bottom) { 667 y_end = io->crop_bottom; // make sure we don't overflow on last row. 668 } 669 if (y_start < io->crop_top) { 670 const int delta = io->crop_top - y_start; 671 y_start = io->crop_top; 672 *in_data += delta * pixel_stride; 673 } 674 if (y_start >= y_end) return 0; // Crop window is empty. 675 676 *in_data += io->crop_left * sizeof(uint32_t); 677 678 io->mb_y = y_start - io->crop_top; 679 io->mb_w = io->crop_right - io->crop_left; 680 io->mb_h = y_end - y_start; 681 return 1; // Non-empty crop window. 682 } 683 684 //------------------------------------------------------------------------------ 685 686 static WEBP_INLINE int GetMetaIndex( 687 const uint32_t* const image, int xsize, int bits, int x, int y) { 688 if (bits == 0) return 0; 689 return image[xsize * (y >> bits) + (x >> bits)]; 690 } 691 692 static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr, 693 int x, int y) { 694 const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_, 695 hdr->huffman_subsample_bits_, x, y); 696 assert(meta_index < hdr->num_htree_groups_); 697 return hdr->htree_groups_ + meta_index; 698 } 699 700 //------------------------------------------------------------------------------ 701 // Main loop, with custom row-processing function 702 703 typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row); 704 705 static void ApplyInverseTransforms(VP8LDecoder* const dec, int num_rows, 706 const uint32_t* const rows) { 707 int n = dec->next_transform_; 708 const int cache_pixs = dec->width_ * num_rows; 709 const int start_row = dec->last_row_; 710 const int end_row = start_row + num_rows; 711 const uint32_t* rows_in = rows; 712 uint32_t* const rows_out = dec->argb_cache_; 713 714 // Inverse transforms. 715 while (n-- > 0) { 716 VP8LTransform* const transform = &dec->transforms_[n]; 717 VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out); 718 rows_in = rows_out; 719 } 720 if (rows_in != rows_out) { 721 // No transform called, hence just copy. 722 memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out)); 723 } 724 } 725 726 // Processes (transforms, scales & color-converts) the rows decoded after the 727 // last call. 728 static void ProcessRows(VP8LDecoder* const dec, int row) { 729 const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_; 730 const int num_rows = row - dec->last_row_; 731 732 assert(row <= dec->io_->crop_bottom); 733 // We can't process more than NUM_ARGB_CACHE_ROWS at a time (that's the size 734 // of argb_cache_), but we currently don't need more than that. 735 assert(num_rows <= NUM_ARGB_CACHE_ROWS); 736 if (num_rows > 0) { // Emit output. 737 VP8Io* const io = dec->io_; 738 uint8_t* rows_data = (uint8_t*)dec->argb_cache_; 739 const int in_stride = io->width * sizeof(uint32_t); // in unit of RGBA 740 741 ApplyInverseTransforms(dec, num_rows, rows); 742 if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) { 743 // Nothing to output (this time). 744 } else { 745 const WebPDecBuffer* const output = dec->output_; 746 if (WebPIsRGBMode(output->colorspace)) { // convert to RGBA 747 const WebPRGBABuffer* const buf = &output->u.RGBA; 748 uint8_t* const rgba = buf->rgba + dec->last_out_row_ * buf->stride; 749 const int num_rows_out = io->use_scaling ? 750 EmitRescaledRowsRGBA(dec, rows_data, in_stride, io->mb_h, 751 rgba, buf->stride) : 752 EmitRows(output->colorspace, rows_data, in_stride, 753 io->mb_w, io->mb_h, rgba, buf->stride); 754 // Update 'last_out_row_'. 755 dec->last_out_row_ += num_rows_out; 756 } else { // convert to YUVA 757 dec->last_out_row_ = io->use_scaling ? 758 EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) : 759 EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h); 760 } 761 assert(dec->last_out_row_ <= output->height); 762 } 763 } 764 765 // Update 'last_row_'. 766 dec->last_row_ = row; 767 assert(dec->last_row_ <= dec->height_); 768 } 769 770 // Row-processing for the special case when alpha data contains only one 771 // transform (color indexing), and trivial non-green literals. 772 static int Is8bOptimizable(const VP8LMetadata* const hdr) { 773 int i; 774 if (hdr->color_cache_size_ > 0) return 0; 775 // When the Huffman tree contains only one symbol, we can skip the 776 // call to ReadSymbol() for red/blue/alpha channels. 777 for (i = 0; i < hdr->num_htree_groups_; ++i) { 778 HuffmanCode** const htrees = hdr->htree_groups_[i].htrees; 779 if (htrees[RED][0].bits > 0) return 0; 780 if (htrees[BLUE][0].bits > 0) return 0; 781 if (htrees[ALPHA][0].bits > 0) return 0; 782 } 783 return 1; 784 } 785 786 static void AlphaApplyFilter(ALPHDecoder* const alph_dec, 787 int first_row, int last_row, 788 uint8_t* out, int stride) { 789 if (alph_dec->filter_ != WEBP_FILTER_NONE) { 790 int y; 791 const uint8_t* prev_line = alph_dec->prev_line_; 792 assert(WebPUnfilters[alph_dec->filter_] != NULL); 793 for (y = first_row; y < last_row; ++y) { 794 WebPUnfilters[alph_dec->filter_](prev_line, out, out, stride); 795 prev_line = out; 796 out += stride; 797 } 798 alph_dec->prev_line_ = prev_line; 799 } 800 } 801 802 static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) { 803 // For vertical and gradient filtering, we need to decode the part above the 804 // crop_top row, in order to have the correct spatial predictors. 805 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque; 806 const int top_row = 807 (alph_dec->filter_ == WEBP_FILTER_NONE || 808 alph_dec->filter_ == WEBP_FILTER_HORIZONTAL) ? dec->io_->crop_top 809 : dec->last_row_; 810 const int first_row = (dec->last_row_ < top_row) ? top_row : dec->last_row_; 811 assert(last_row <= dec->io_->crop_bottom); 812 if (last_row > first_row) { 813 // Special method for paletted alpha data. We only process the cropped area. 814 const int width = dec->io_->width; 815 uint8_t* out = alph_dec->output_ + width * first_row; 816 const uint8_t* const in = 817 (uint8_t*)dec->pixels_ + dec->width_ * first_row; 818 VP8LTransform* const transform = &dec->transforms_[0]; 819 assert(dec->next_transform_ == 1); 820 assert(transform->type_ == COLOR_INDEXING_TRANSFORM); 821 VP8LColorIndexInverseTransformAlpha(transform, first_row, last_row, 822 in, out); 823 AlphaApplyFilter(alph_dec, first_row, last_row, out, width); 824 } 825 dec->last_row_ = dec->last_out_row_ = last_row; 826 } 827 828 //------------------------------------------------------------------------------ 829 // Helper functions for fast pattern copy (8b and 32b) 830 831 // cyclic rotation of pattern word 832 static WEBP_INLINE uint32_t Rotate8b(uint32_t V) { 833 #if defined(WORDS_BIGENDIAN) 834 return ((V & 0xff000000u) >> 24) | (V << 8); 835 #else 836 return ((V & 0xffu) << 24) | (V >> 8); 837 #endif 838 } 839 840 // copy 1, 2 or 4-bytes pattern 841 static WEBP_INLINE void CopySmallPattern8b(const uint8_t* src, uint8_t* dst, 842 int length, uint32_t pattern) { 843 int i; 844 // align 'dst' to 4-bytes boundary. Adjust the pattern along the way. 845 while ((uintptr_t)dst & 3) { 846 *dst++ = *src++; 847 pattern = Rotate8b(pattern); 848 --length; 849 } 850 // Copy the pattern 4 bytes at a time. 851 for (i = 0; i < (length >> 2); ++i) { 852 ((uint32_t*)dst)[i] = pattern; 853 } 854 // Finish with left-overs. 'pattern' is still correctly positioned, 855 // so no Rotate8b() call is needed. 856 for (i <<= 2; i < length; ++i) { 857 dst[i] = src[i]; 858 } 859 } 860 861 static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) { 862 const uint8_t* src = dst - dist; 863 if (length >= 8) { 864 uint32_t pattern = 0; 865 switch (dist) { 866 case 1: 867 pattern = src[0]; 868 #if defined(__arm__) || defined(_M_ARM) // arm doesn't like multiply that much 869 pattern |= pattern << 8; 870 pattern |= pattern << 16; 871 #elif defined(WEBP_USE_MIPS_DSP_R2) 872 __asm__ volatile ("replv.qb %0, %0" : "+r"(pattern)); 873 #else 874 pattern = 0x01010101u * pattern; 875 #endif 876 break; 877 case 2: 878 memcpy(&pattern, src, sizeof(uint16_t)); 879 #if defined(__arm__) || defined(_M_ARM) 880 pattern |= pattern << 16; 881 #elif defined(WEBP_USE_MIPS_DSP_R2) 882 __asm__ volatile ("replv.ph %0, %0" : "+r"(pattern)); 883 #else 884 pattern = 0x00010001u * pattern; 885 #endif 886 break; 887 case 4: 888 memcpy(&pattern, src, sizeof(uint32_t)); 889 break; 890 default: 891 goto Copy; 892 break; 893 } 894 CopySmallPattern8b(src, dst, length, pattern); 895 return; 896 } 897 Copy: 898 if (dist >= length) { // no overlap -> use memcpy() 899 memcpy(dst, src, length * sizeof(*dst)); 900 } else { 901 int i; 902 for (i = 0; i < length; ++i) dst[i] = src[i]; 903 } 904 } 905 906 // copy pattern of 1 or 2 uint32_t's 907 static WEBP_INLINE void CopySmallPattern32b(const uint32_t* src, 908 uint32_t* dst, 909 int length, uint64_t pattern) { 910 int i; 911 if ((uintptr_t)dst & 4) { // Align 'dst' to 8-bytes boundary. 912 *dst++ = *src++; 913 pattern = (pattern >> 32) | (pattern << 32); 914 --length; 915 } 916 assert(0 == ((uintptr_t)dst & 7)); 917 for (i = 0; i < (length >> 1); ++i) { 918 ((uint64_t*)dst)[i] = pattern; // Copy the pattern 8 bytes at a time. 919 } 920 if (length & 1) { // Finish with left-over. 921 dst[i << 1] = src[i << 1]; 922 } 923 } 924 925 static WEBP_INLINE void CopyBlock32b(uint32_t* const dst, 926 int dist, int length) { 927 const uint32_t* const src = dst - dist; 928 if (dist <= 2 && length >= 4 && ((uintptr_t)dst & 3) == 0) { 929 uint64_t pattern; 930 if (dist == 1) { 931 pattern = (uint64_t)src[0]; 932 pattern |= pattern << 32; 933 } else { 934 memcpy(&pattern, src, sizeof(pattern)); 935 } 936 CopySmallPattern32b(src, dst, length, pattern); 937 } else if (dist >= length) { // no overlap 938 memcpy(dst, src, length * sizeof(*dst)); 939 } else { 940 int i; 941 for (i = 0; i < length; ++i) dst[i] = src[i]; 942 } 943 } 944 945 //------------------------------------------------------------------------------ 946 947 static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data, 948 int width, int height, int last_row) { 949 int ok = 1; 950 int row = dec->last_pixel_ / width; 951 int col = dec->last_pixel_ % width; 952 VP8LBitReader* const br = &dec->br_; 953 VP8LMetadata* const hdr = &dec->hdr_; 954 int pos = dec->last_pixel_; // current position 955 const int end = width * height; // End of data 956 const int last = width * last_row; // Last pixel to decode 957 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES; 958 const int mask = hdr->huffman_mask_; 959 const HTreeGroup* htree_group = 960 (pos < last) ? GetHtreeGroupForPos(hdr, col, row) : NULL; 961 assert(pos <= end); 962 assert(last_row <= height); 963 assert(Is8bOptimizable(hdr)); 964 965 while (!br->eos_ && pos < last) { 966 int code; 967 // Only update when changing tile. 968 if ((col & mask) == 0) { 969 htree_group = GetHtreeGroupForPos(hdr, col, row); 970 } 971 assert(htree_group != NULL); 972 VP8LFillBitWindow(br); 973 code = ReadSymbol(htree_group->htrees[GREEN], br); 974 if (code < NUM_LITERAL_CODES) { // Literal 975 data[pos] = code; 976 ++pos; 977 ++col; 978 if (col >= width) { 979 col = 0; 980 ++row; 981 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) { 982 ExtractPalettedAlphaRows(dec, row); 983 } 984 } 985 } else if (code < len_code_limit) { // Backward reference 986 int dist_code, dist; 987 const int length_sym = code - NUM_LITERAL_CODES; 988 const int length = GetCopyLength(length_sym, br); 989 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br); 990 VP8LFillBitWindow(br); 991 dist_code = GetCopyDistance(dist_symbol, br); 992 dist = PlaneCodeToDistance(width, dist_code); 993 if (pos >= dist && end - pos >= length) { 994 CopyBlock8b(data + pos, dist, length); 995 } else { 996 ok = 0; 997 goto End; 998 } 999 pos += length; 1000 col += length; 1001 while (col >= width) { 1002 col -= width; 1003 ++row; 1004 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) { 1005 ExtractPalettedAlphaRows(dec, row); 1006 } 1007 } 1008 if (pos < last && (col & mask)) { 1009 htree_group = GetHtreeGroupForPos(hdr, col, row); 1010 } 1011 } else { // Not reached 1012 ok = 0; 1013 goto End; 1014 } 1015 assert(br->eos_ == VP8LIsEndOfStream(br)); 1016 } 1017 // Process the remaining rows corresponding to last row-block. 1018 ExtractPalettedAlphaRows(dec, row > last_row ? last_row : row); 1019 1020 End: 1021 if (!ok || (br->eos_ && pos < end)) { 1022 ok = 0; 1023 dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED 1024 : VP8_STATUS_BITSTREAM_ERROR; 1025 } else { 1026 dec->last_pixel_ = pos; 1027 } 1028 return ok; 1029 } 1030 1031 static void SaveState(VP8LDecoder* const dec, int last_pixel) { 1032 assert(dec->incremental_); 1033 dec->saved_br_ = dec->br_; 1034 dec->saved_last_pixel_ = last_pixel; 1035 if (dec->hdr_.color_cache_size_ > 0) { 1036 VP8LColorCacheCopy(&dec->hdr_.color_cache_, &dec->hdr_.saved_color_cache_); 1037 } 1038 } 1039 1040 static void RestoreState(VP8LDecoder* const dec) { 1041 assert(dec->br_.eos_); 1042 dec->status_ = VP8_STATUS_SUSPENDED; 1043 dec->br_ = dec->saved_br_; 1044 dec->last_pixel_ = dec->saved_last_pixel_; 1045 if (dec->hdr_.color_cache_size_ > 0) { 1046 VP8LColorCacheCopy(&dec->hdr_.saved_color_cache_, &dec->hdr_.color_cache_); 1047 } 1048 } 1049 1050 #define SYNC_EVERY_N_ROWS 8 // minimum number of rows between check-points 1051 static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data, 1052 int width, int height, int last_row, 1053 ProcessRowsFunc process_func) { 1054 int row = dec->last_pixel_ / width; 1055 int col = dec->last_pixel_ % width; 1056 VP8LBitReader* const br = &dec->br_; 1057 VP8LMetadata* const hdr = &dec->hdr_; 1058 uint32_t* src = data + dec->last_pixel_; 1059 uint32_t* last_cached = src; 1060 uint32_t* const src_end = data + width * height; // End of data 1061 uint32_t* const src_last = data + width * last_row; // Last pixel to decode 1062 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES; 1063 const int color_cache_limit = len_code_limit + hdr->color_cache_size_; 1064 int next_sync_row = dec->incremental_ ? row : 1 << 24; 1065 VP8LColorCache* const color_cache = 1066 (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL; 1067 const int mask = hdr->huffman_mask_; 1068 const HTreeGroup* htree_group = 1069 (src < src_last) ? GetHtreeGroupForPos(hdr, col, row) : NULL; 1070 assert(dec->last_row_ < last_row); 1071 assert(src_last <= src_end); 1072 1073 while (src < src_last) { 1074 int code; 1075 if (row >= next_sync_row) { 1076 SaveState(dec, (int)(src - data)); 1077 next_sync_row = row + SYNC_EVERY_N_ROWS; 1078 } 1079 // Only update when changing tile. Note we could use this test: 1080 // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed 1081 // but that's actually slower and needs storing the previous col/row. 1082 if ((col & mask) == 0) { 1083 htree_group = GetHtreeGroupForPos(hdr, col, row); 1084 } 1085 assert(htree_group != NULL); 1086 if (htree_group->is_trivial_code) { 1087 *src = htree_group->literal_arb; 1088 goto AdvanceByOne; 1089 } 1090 VP8LFillBitWindow(br); 1091 if (htree_group->use_packed_table) { 1092 code = ReadPackedSymbols(htree_group, br, src); 1093 if (code == PACKED_NON_LITERAL_CODE) goto AdvanceByOne; 1094 } else { 1095 code = ReadSymbol(htree_group->htrees[GREEN], br); 1096 } 1097 if (br->eos_) break; // early out 1098 if (code < NUM_LITERAL_CODES) { // Literal 1099 if (htree_group->is_trivial_literal) { 1100 *src = htree_group->literal_arb | (code << 8); 1101 } else { 1102 int red, blue, alpha; 1103 red = ReadSymbol(htree_group->htrees[RED], br); 1104 VP8LFillBitWindow(br); 1105 blue = ReadSymbol(htree_group->htrees[BLUE], br); 1106 alpha = ReadSymbol(htree_group->htrees[ALPHA], br); 1107 if (br->eos_) break; 1108 *src = ((uint32_t)alpha << 24) | (red << 16) | (code << 8) | blue; 1109 } 1110 AdvanceByOne: 1111 ++src; 1112 ++col; 1113 if (col >= width) { 1114 col = 0; 1115 ++row; 1116 if (process_func != NULL) { 1117 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) { 1118 process_func(dec, row); 1119 } 1120 } 1121 if (color_cache != NULL) { 1122 while (last_cached < src) { 1123 VP8LColorCacheInsert(color_cache, *last_cached++); 1124 } 1125 } 1126 } 1127 } else if (code < len_code_limit) { // Backward reference 1128 int dist_code, dist; 1129 const int length_sym = code - NUM_LITERAL_CODES; 1130 const int length = GetCopyLength(length_sym, br); 1131 const int dist_symbol = ReadSymbol(htree_group->htrees[DIST], br); 1132 VP8LFillBitWindow(br); 1133 dist_code = GetCopyDistance(dist_symbol, br); 1134 dist = PlaneCodeToDistance(width, dist_code); 1135 if (br->eos_) break; 1136 if (src - data < (ptrdiff_t)dist || src_end - src < (ptrdiff_t)length) { 1137 goto Error; 1138 } else { 1139 CopyBlock32b(src, dist, length); 1140 } 1141 src += length; 1142 col += length; 1143 while (col >= width) { 1144 col -= width; 1145 ++row; 1146 if (process_func != NULL) { 1147 if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) { 1148 process_func(dec, row); 1149 } 1150 } 1151 } 1152 // Because of the check done above (before 'src' was incremented by 1153 // 'length'), the following holds true. 1154 assert(src <= src_end); 1155 if (col & mask) htree_group = GetHtreeGroupForPos(hdr, col, row); 1156 if (color_cache != NULL) { 1157 while (last_cached < src) { 1158 VP8LColorCacheInsert(color_cache, *last_cached++); 1159 } 1160 } 1161 } else if (code < color_cache_limit) { // Color cache 1162 const int key = code - len_code_limit; 1163 assert(color_cache != NULL); 1164 while (last_cached < src) { 1165 VP8LColorCacheInsert(color_cache, *last_cached++); 1166 } 1167 *src = VP8LColorCacheLookup(color_cache, key); 1168 goto AdvanceByOne; 1169 } else { // Not reached 1170 goto Error; 1171 } 1172 assert(br->eos_ == VP8LIsEndOfStream(br)); 1173 } 1174 1175 if (dec->incremental_ && br->eos_ && src < src_end) { 1176 RestoreState(dec); 1177 } else if (!br->eos_) { 1178 // Process the remaining rows corresponding to last row-block. 1179 if (process_func != NULL) { 1180 process_func(dec, row > last_row ? last_row : row); 1181 } 1182 dec->status_ = VP8_STATUS_OK; 1183 dec->last_pixel_ = (int)(src - data); // end-of-scan marker 1184 } else { 1185 // if not incremental, and we are past the end of buffer (eos_=1), then this 1186 // is a real bitstream error. 1187 goto Error; 1188 } 1189 return 1; 1190 1191 Error: 1192 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1193 return 0; 1194 } 1195 1196 // ----------------------------------------------------------------------------- 1197 // VP8LTransform 1198 1199 static void ClearTransform(VP8LTransform* const transform) { 1200 WebPSafeFree(transform->data_); 1201 transform->data_ = NULL; 1202 } 1203 1204 // For security reason, we need to remap the color map to span 1205 // the total possible bundled values, and not just the num_colors. 1206 static int ExpandColorMap(int num_colors, VP8LTransform* const transform) { 1207 int i; 1208 const int final_num_colors = 1 << (8 >> transform->bits_); 1209 uint32_t* const new_color_map = 1210 (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors, 1211 sizeof(*new_color_map)); 1212 if (new_color_map == NULL) { 1213 return 0; 1214 } else { 1215 uint8_t* const data = (uint8_t*)transform->data_; 1216 uint8_t* const new_data = (uint8_t*)new_color_map; 1217 new_color_map[0] = transform->data_[0]; 1218 for (i = 4; i < 4 * num_colors; ++i) { 1219 // Equivalent to AddPixelEq(), on a byte-basis. 1220 new_data[i] = (data[i] + new_data[i - 4]) & 0xff; 1221 } 1222 for (; i < 4 * final_num_colors; ++i) { 1223 new_data[i] = 0; // black tail. 1224 } 1225 WebPSafeFree(transform->data_); 1226 transform->data_ = new_color_map; 1227 } 1228 return 1; 1229 } 1230 1231 static int ReadTransform(int* const xsize, int const* ysize, 1232 VP8LDecoder* const dec) { 1233 int ok = 1; 1234 VP8LBitReader* const br = &dec->br_; 1235 VP8LTransform* transform = &dec->transforms_[dec->next_transform_]; 1236 const VP8LImageTransformType type = 1237 (VP8LImageTransformType)VP8LReadBits(br, 2); 1238 1239 // Each transform type can only be present once in the stream. 1240 if (dec->transforms_seen_ & (1U << type)) { 1241 return 0; // Already there, let's not accept the second same transform. 1242 } 1243 dec->transforms_seen_ |= (1U << type); 1244 1245 transform->type_ = type; 1246 transform->xsize_ = *xsize; 1247 transform->ysize_ = *ysize; 1248 transform->data_ = NULL; 1249 ++dec->next_transform_; 1250 assert(dec->next_transform_ <= NUM_TRANSFORMS); 1251 1252 switch (type) { 1253 case PREDICTOR_TRANSFORM: 1254 case CROSS_COLOR_TRANSFORM: 1255 transform->bits_ = VP8LReadBits(br, 3) + 2; 1256 ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_, 1257 transform->bits_), 1258 VP8LSubSampleSize(transform->ysize_, 1259 transform->bits_), 1260 0, dec, &transform->data_); 1261 break; 1262 case COLOR_INDEXING_TRANSFORM: { 1263 const int num_colors = VP8LReadBits(br, 8) + 1; 1264 const int bits = (num_colors > 16) ? 0 1265 : (num_colors > 4) ? 1 1266 : (num_colors > 2) ? 2 1267 : 3; 1268 *xsize = VP8LSubSampleSize(transform->xsize_, bits); 1269 transform->bits_ = bits; 1270 ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_); 1271 ok = ok && ExpandColorMap(num_colors, transform); 1272 break; 1273 } 1274 case SUBTRACT_GREEN: 1275 break; 1276 default: 1277 assert(0); // can't happen 1278 break; 1279 } 1280 1281 return ok; 1282 } 1283 1284 // ----------------------------------------------------------------------------- 1285 // VP8LMetadata 1286 1287 static void InitMetadata(VP8LMetadata* const hdr) { 1288 assert(hdr != NULL); 1289 memset(hdr, 0, sizeof(*hdr)); 1290 } 1291 1292 static void ClearMetadata(VP8LMetadata* const hdr) { 1293 assert(hdr != NULL); 1294 1295 WebPSafeFree(hdr->huffman_image_); 1296 WebPSafeFree(hdr->huffman_tables_); 1297 VP8LHtreeGroupsFree(hdr->htree_groups_); 1298 VP8LColorCacheClear(&hdr->color_cache_); 1299 VP8LColorCacheClear(&hdr->saved_color_cache_); 1300 InitMetadata(hdr); 1301 } 1302 1303 // ----------------------------------------------------------------------------- 1304 // VP8LDecoder 1305 1306 VP8LDecoder* VP8LNew(void) { 1307 VP8LDecoder* const dec = (VP8LDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec)); 1308 if (dec == NULL) return NULL; 1309 dec->status_ = VP8_STATUS_OK; 1310 dec->state_ = READ_DIM; 1311 1312 VP8LDspInit(); // Init critical function pointers. 1313 1314 return dec; 1315 } 1316 1317 void VP8LClear(VP8LDecoder* const dec) { 1318 int i; 1319 if (dec == NULL) return; 1320 ClearMetadata(&dec->hdr_); 1321 1322 WebPSafeFree(dec->pixels_); 1323 dec->pixels_ = NULL; 1324 for (i = 0; i < dec->next_transform_; ++i) { 1325 ClearTransform(&dec->transforms_[i]); 1326 } 1327 dec->next_transform_ = 0; 1328 dec->transforms_seen_ = 0; 1329 1330 WebPSafeFree(dec->rescaler_memory); 1331 dec->rescaler_memory = NULL; 1332 1333 dec->output_ = NULL; // leave no trace behind 1334 } 1335 1336 void VP8LDelete(VP8LDecoder* const dec) { 1337 if (dec != NULL) { 1338 VP8LClear(dec); 1339 WebPSafeFree(dec); 1340 } 1341 } 1342 1343 static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) { 1344 VP8LMetadata* const hdr = &dec->hdr_; 1345 const int num_bits = hdr->huffman_subsample_bits_; 1346 dec->width_ = width; 1347 dec->height_ = height; 1348 1349 hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits); 1350 hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1; 1351 } 1352 1353 static int DecodeImageStream(int xsize, int ysize, 1354 int is_level0, 1355 VP8LDecoder* const dec, 1356 uint32_t** const decoded_data) { 1357 int ok = 1; 1358 int transform_xsize = xsize; 1359 int transform_ysize = ysize; 1360 VP8LBitReader* const br = &dec->br_; 1361 VP8LMetadata* const hdr = &dec->hdr_; 1362 uint32_t* data = NULL; 1363 int color_cache_bits = 0; 1364 1365 // Read the transforms (may recurse). 1366 if (is_level0) { 1367 while (ok && VP8LReadBits(br, 1)) { 1368 ok = ReadTransform(&transform_xsize, &transform_ysize, dec); 1369 } 1370 } 1371 1372 // Color cache 1373 if (ok && VP8LReadBits(br, 1)) { 1374 color_cache_bits = VP8LReadBits(br, 4); 1375 ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS); 1376 if (!ok) { 1377 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1378 goto End; 1379 } 1380 } 1381 1382 // Read the Huffman codes (may recurse). 1383 ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize, 1384 color_cache_bits, is_level0); 1385 if (!ok) { 1386 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1387 goto End; 1388 } 1389 1390 // Finish setting up the color-cache 1391 if (color_cache_bits > 0) { 1392 hdr->color_cache_size_ = 1 << color_cache_bits; 1393 if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) { 1394 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1395 ok = 0; 1396 goto End; 1397 } 1398 } else { 1399 hdr->color_cache_size_ = 0; 1400 } 1401 UpdateDecoder(dec, transform_xsize, transform_ysize); 1402 1403 if (is_level0) { // level 0 complete 1404 dec->state_ = READ_HDR; 1405 goto End; 1406 } 1407 1408 { 1409 const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize; 1410 data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data)); 1411 if (data == NULL) { 1412 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1413 ok = 0; 1414 goto End; 1415 } 1416 } 1417 1418 // Use the Huffman trees to decode the LZ77 encoded data. 1419 ok = DecodeImageData(dec, data, transform_xsize, transform_ysize, 1420 transform_ysize, NULL); 1421 ok = ok && !br->eos_; 1422 1423 End: 1424 if (!ok) { 1425 WebPSafeFree(data); 1426 ClearMetadata(hdr); 1427 } else { 1428 if (decoded_data != NULL) { 1429 *decoded_data = data; 1430 } else { 1431 // We allocate image data in this function only for transforms. At level 0 1432 // (that is: not the transforms), we shouldn't have allocated anything. 1433 assert(data == NULL); 1434 assert(is_level0); 1435 } 1436 dec->last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls. 1437 if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind. 1438 } 1439 return ok; 1440 } 1441 1442 //------------------------------------------------------------------------------ 1443 // Allocate internal buffers dec->pixels_ and dec->argb_cache_. 1444 static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) { 1445 const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_; 1446 // Scratch buffer corresponding to top-prediction row for transforming the 1447 // first row in the row-blocks. Not needed for paletted alpha. 1448 const uint64_t cache_top_pixels = (uint16_t)final_width; 1449 // Scratch buffer for temporary BGRA storage. Not needed for paletted alpha. 1450 const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS; 1451 const uint64_t total_num_pixels = 1452 num_pixels + cache_top_pixels + cache_pixels; 1453 1454 assert(dec->width_ <= final_width); 1455 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t)); 1456 if (dec->pixels_ == NULL) { 1457 dec->argb_cache_ = NULL; // for sanity check 1458 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1459 return 0; 1460 } 1461 dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels; 1462 return 1; 1463 } 1464 1465 static int AllocateInternalBuffers8b(VP8LDecoder* const dec) { 1466 const uint64_t total_num_pixels = (uint64_t)dec->width_ * dec->height_; 1467 dec->argb_cache_ = NULL; // for sanity check 1468 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t)); 1469 if (dec->pixels_ == NULL) { 1470 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1471 return 0; 1472 } 1473 return 1; 1474 } 1475 1476 //------------------------------------------------------------------------------ 1477 1478 // Special row-processing that only stores the alpha data. 1479 static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) { 1480 int cur_row = dec->last_row_; 1481 int num_rows = last_row - cur_row; 1482 const uint32_t* in = dec->pixels_ + dec->width_ * cur_row; 1483 1484 assert(last_row <= dec->io_->crop_bottom); 1485 while (num_rows > 0) { 1486 const int num_rows_to_process = 1487 (num_rows > NUM_ARGB_CACHE_ROWS) ? NUM_ARGB_CACHE_ROWS : num_rows; 1488 // Extract alpha (which is stored in the green plane). 1489 ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque; 1490 uint8_t* const output = alph_dec->output_; 1491 const int width = dec->io_->width; // the final width (!= dec->width_) 1492 const int cache_pixs = width * num_rows_to_process; 1493 uint8_t* const dst = output + width * cur_row; 1494 const uint32_t* const src = dec->argb_cache_; 1495 ApplyInverseTransforms(dec, num_rows_to_process, in); 1496 WebPExtractGreen(src, dst, cache_pixs); 1497 AlphaApplyFilter(alph_dec, 1498 cur_row, cur_row + num_rows_to_process, dst, width); 1499 num_rows -= num_rows_to_process; 1500 in += num_rows_to_process * dec->width_; 1501 cur_row += num_rows_to_process; 1502 } 1503 assert(cur_row == last_row); 1504 dec->last_row_ = dec->last_out_row_ = last_row; 1505 } 1506 1507 int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec, 1508 const uint8_t* const data, size_t data_size) { 1509 int ok = 0; 1510 VP8LDecoder* dec = VP8LNew(); 1511 1512 if (dec == NULL) return 0; 1513 1514 assert(alph_dec != NULL); 1515 alph_dec->vp8l_dec_ = dec; 1516 1517 dec->width_ = alph_dec->width_; 1518 dec->height_ = alph_dec->height_; 1519 dec->io_ = &alph_dec->io_; 1520 dec->io_->opaque = alph_dec; 1521 dec->io_->width = alph_dec->width_; 1522 dec->io_->height = alph_dec->height_; 1523 1524 dec->status_ = VP8_STATUS_OK; 1525 VP8LInitBitReader(&dec->br_, data, data_size); 1526 1527 if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) { 1528 goto Err; 1529 } 1530 1531 // Special case: if alpha data uses only the color indexing transform and 1532 // doesn't use color cache (a frequent case), we will use DecodeAlphaData() 1533 // method that only needs allocation of 1 byte per pixel (alpha channel). 1534 if (dec->next_transform_ == 1 && 1535 dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM && 1536 Is8bOptimizable(&dec->hdr_)) { 1537 alph_dec->use_8b_decode_ = 1; 1538 ok = AllocateInternalBuffers8b(dec); 1539 } else { 1540 // Allocate internal buffers (note that dec->width_ may have changed here). 1541 alph_dec->use_8b_decode_ = 0; 1542 ok = AllocateInternalBuffers32b(dec, alph_dec->width_); 1543 } 1544 1545 if (!ok) goto Err; 1546 1547 return 1; 1548 1549 Err: 1550 VP8LDelete(alph_dec->vp8l_dec_); 1551 alph_dec->vp8l_dec_ = NULL; 1552 return 0; 1553 } 1554 1555 int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) { 1556 VP8LDecoder* const dec = alph_dec->vp8l_dec_; 1557 assert(dec != NULL); 1558 assert(last_row <= dec->height_); 1559 1560 if (dec->last_row_ >= last_row) { 1561 return 1; // done 1562 } 1563 1564 if (!alph_dec->use_8b_decode_) WebPInitAlphaProcessing(); 1565 1566 // Decode (with special row processing). 1567 return alph_dec->use_8b_decode_ ? 1568 DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_, 1569 last_row) : 1570 DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_, 1571 last_row, ExtractAlphaRows); 1572 } 1573 1574 //------------------------------------------------------------------------------ 1575 1576 int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) { 1577 int width, height, has_alpha; 1578 1579 if (dec == NULL) return 0; 1580 if (io == NULL) { 1581 dec->status_ = VP8_STATUS_INVALID_PARAM; 1582 return 0; 1583 } 1584 1585 dec->io_ = io; 1586 dec->status_ = VP8_STATUS_OK; 1587 VP8LInitBitReader(&dec->br_, io->data, io->data_size); 1588 if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) { 1589 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1590 goto Error; 1591 } 1592 dec->state_ = READ_DIM; 1593 io->width = width; 1594 io->height = height; 1595 1596 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error; 1597 return 1; 1598 1599 Error: 1600 VP8LClear(dec); 1601 assert(dec->status_ != VP8_STATUS_OK); 1602 return 0; 1603 } 1604 1605 int VP8LDecodeImage(VP8LDecoder* const dec) { 1606 VP8Io* io = NULL; 1607 WebPDecParams* params = NULL; 1608 1609 // Sanity checks. 1610 if (dec == NULL) return 0; 1611 1612 assert(dec->hdr_.huffman_tables_ != NULL); 1613 assert(dec->hdr_.htree_groups_ != NULL); 1614 assert(dec->hdr_.num_htree_groups_ > 0); 1615 1616 io = dec->io_; 1617 assert(io != NULL); 1618 params = (WebPDecParams*)io->opaque; 1619 assert(params != NULL); 1620 1621 // Initialization. 1622 if (dec->state_ != READ_DATA) { 1623 dec->output_ = params->output; 1624 assert(dec->output_ != NULL); 1625 1626 if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) { 1627 dec->status_ = VP8_STATUS_INVALID_PARAM; 1628 goto Err; 1629 } 1630 1631 if (!AllocateInternalBuffers32b(dec, io->width)) goto Err; 1632 1633 if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err; 1634 1635 if (io->use_scaling || WebPIsPremultipliedMode(dec->output_->colorspace)) { 1636 // need the alpha-multiply functions for premultiplied output or rescaling 1637 WebPInitAlphaProcessing(); 1638 } 1639 if (!WebPIsRGBMode(dec->output_->colorspace)) { 1640 WebPInitConvertARGBToYUV(); 1641 if (dec->output_->u.YUVA.a != NULL) WebPInitAlphaProcessing(); 1642 } 1643 if (dec->incremental_) { 1644 if (dec->hdr_.color_cache_size_ > 0 && 1645 dec->hdr_.saved_color_cache_.colors_ == NULL) { 1646 if (!VP8LColorCacheInit(&dec->hdr_.saved_color_cache_, 1647 dec->hdr_.color_cache_.hash_bits_)) { 1648 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1649 goto Err; 1650 } 1651 } 1652 } 1653 dec->state_ = READ_DATA; 1654 } 1655 1656 // Decode. 1657 if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_, 1658 io->crop_bottom, ProcessRows)) { 1659 goto Err; 1660 } 1661 1662 params->last_y = dec->last_out_row_; 1663 return 1; 1664 1665 Err: 1666 VP8LClear(dec); 1667 assert(dec->status_ != VP8_STATUS_OK); 1668 return 0; 1669 } 1670 1671 //------------------------------------------------------------------------------ 1672
