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| 1 // Copyright 2012 Google Inc. All Rights Reserved. |
| 2 // |
| 3 // This code is licensed under the same terms as WebM: |
| 4 // Software License Agreement: http://www.webmproject.org/license/software/ |
| 5 // Additional IP Rights Grant: http://www.webmproject.org/license/additional/ |
| 6 // ----------------------------------------------------------------------------- |
| 7 // |
| 8 // main entry for the decoder |
| 9 // |
| 10 // Authors: Vikas Arora (vikaas.arora@gmail.com) |
| 11 // Jyrki Alakuijala (jyrki@google.com) |
| 12 |
| 13 #include <stdio.h> |
| 14 #include <stdlib.h> |
| 15 #include "./vp8li.h" |
| 16 #include "../dsp/lossless.h" |
| 17 #include "../dsp/yuv.h" |
| 18 #include "../utils/huffman.h" |
| 19 #include "../utils/utils.h" |
| 20 |
| 21 #if defined(__cplusplus) || defined(c_plusplus) |
| 22 extern "C" { |
| 23 #endif |
| 24 |
| 25 #define NUM_ARGB_CACHE_ROWS 16 |
| 26 |
| 27 static const int kCodeLengthLiterals = 16; |
| 28 static const int kCodeLengthRepeatCode = 16; |
| 29 static const int kCodeLengthExtraBits[3] = { 2, 3, 7 }; |
| 30 static const int kCodeLengthRepeatOffsets[3] = { 3, 3, 11 }; |
| 31 |
| 32 // ----------------------------------------------------------------------------- |
| 33 // Five Huffman codes are used at each meta code: |
| 34 // 1. green + length prefix codes + color cache codes, |
| 35 // 2. alpha, |
| 36 // 3. red, |
| 37 // 4. blue, and, |
| 38 // 5. distance prefix codes. |
| 39 typedef enum { |
| 40 GREEN = 0, |
| 41 RED = 1, |
| 42 BLUE = 2, |
| 43 ALPHA = 3, |
| 44 DIST = 4 |
| 45 } HuffIndex; |
| 46 |
| 47 static const uint16_t kAlphabetSize[HUFFMAN_CODES_PER_META_CODE] = { |
| 48 NUM_LITERAL_CODES + NUM_LENGTH_CODES, |
| 49 NUM_LITERAL_CODES, NUM_LITERAL_CODES, NUM_LITERAL_CODES, |
| 50 NUM_DISTANCE_CODES |
| 51 }; |
| 52 |
| 53 |
| 54 #define NUM_CODE_LENGTH_CODES 19 |
| 55 static const uint8_t kCodeLengthCodeOrder[NUM_CODE_LENGTH_CODES] = { |
| 56 17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 |
| 57 }; |
| 58 |
| 59 #define CODE_TO_PLANE_CODES 120 |
| 60 static const uint8_t code_to_plane_lut[CODE_TO_PLANE_CODES] = { |
| 61 0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a, |
| 62 0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a, |
| 63 0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b, |
| 64 0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03, |
| 65 0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c, |
| 66 0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e, |
| 67 0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b, |
| 68 0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f, |
| 69 0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b, |
| 70 0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41, |
| 71 0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f, |
| 72 0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70 |
| 73 }; |
| 74 |
| 75 static int DecodeImageStream(int xsize, int ysize, |
| 76 int is_level0, |
| 77 VP8LDecoder* const dec, |
| 78 uint32_t** const decoded_data); |
| 79 |
| 80 //------------------------------------------------------------------------------ |
| 81 |
| 82 int VP8LCheckSignature(const uint8_t* const data, size_t size) { |
| 83 return (size >= 1) && (data[0] == VP8L_MAGIC_BYTE); |
| 84 } |
| 85 |
| 86 static int ReadImageInfo(VP8LBitReader* const br, |
| 87 int* const width, int* const height, |
| 88 int* const has_alpha) { |
| 89 const uint8_t signature = VP8LReadBits(br, 8); |
| 90 if (!VP8LCheckSignature(&signature, 1)) { |
| 91 return 0; |
| 92 } |
| 93 *width = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1; |
| 94 *height = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1; |
| 95 *has_alpha = VP8LReadBits(br, 1); |
| 96 VP8LReadBits(br, VP8L_VERSION_BITS); // Read/ignore the version number. |
| 97 return 1; |
| 98 } |
| 99 |
| 100 int VP8LGetInfo(const uint8_t* data, size_t data_size, |
| 101 int* const width, int* const height, int* const has_alpha) { |
| 102 if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) { |
| 103 return 0; // not enough data |
| 104 } else { |
| 105 int w, h, a; |
| 106 VP8LBitReader br; |
| 107 VP8LInitBitReader(&br, data, data_size); |
| 108 if (!ReadImageInfo(&br, &w, &h, &a)) { |
| 109 return 0; |
| 110 } |
| 111 if (width != NULL) *width = w; |
| 112 if (height != NULL) *height = h; |
| 113 if (has_alpha != NULL) *has_alpha = a; |
| 114 return 1; |
| 115 } |
| 116 } |
| 117 |
| 118 //------------------------------------------------------------------------------ |
| 119 |
| 120 static WEBP_INLINE int GetCopyDistance(int distance_symbol, |
| 121 VP8LBitReader* const br) { |
| 122 int extra_bits, offset; |
| 123 if (distance_symbol < 4) { |
| 124 return distance_symbol + 1; |
| 125 } |
| 126 extra_bits = (distance_symbol - 2) >> 1; |
| 127 offset = (2 + (distance_symbol & 1)) << extra_bits; |
| 128 return offset + VP8LReadBits(br, extra_bits) + 1; |
| 129 } |
| 130 |
| 131 static WEBP_INLINE int GetCopyLength(int length_symbol, |
| 132 VP8LBitReader* const br) { |
| 133 // Length and distance prefixes are encoded the same way. |
| 134 return GetCopyDistance(length_symbol, br); |
| 135 } |
| 136 |
| 137 static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) { |
| 138 if (plane_code > CODE_TO_PLANE_CODES) { |
| 139 return plane_code - CODE_TO_PLANE_CODES; |
| 140 } else { |
| 141 const int dist_code = code_to_plane_lut[plane_code - 1]; |
| 142 const int yoffset = dist_code >> 4; |
| 143 const int xoffset = 8 - (dist_code & 0xf); |
| 144 const int dist = yoffset * xsize + xoffset; |
| 145 return (dist >= 1) ? dist : 1; |
| 146 } |
| 147 } |
| 148 |
| 149 //------------------------------------------------------------------------------ |
| 150 // Decodes the next Huffman code from bit-stream. |
| 151 // FillBitWindow(br) needs to be called at minimum every second call |
| 152 // to ReadSymbolUnsafe. |
| 153 static int ReadSymbolUnsafe(const HuffmanTree* tree, VP8LBitReader* const br) { |
| 154 const HuffmanTreeNode* node = tree->root_; |
| 155 assert(node != NULL); |
| 156 while (!HuffmanTreeNodeIsLeaf(node)) { |
| 157 node = HuffmanTreeNextNode(node, VP8LReadOneBitUnsafe(br)); |
| 158 } |
| 159 return node->symbol_; |
| 160 } |
| 161 |
| 162 static WEBP_INLINE int ReadSymbol(const HuffmanTree* tree, |
| 163 VP8LBitReader* const br) { |
| 164 const int read_safe = (br->pos_ + 8 > br->len_); |
| 165 if (!read_safe) { |
| 166 return ReadSymbolUnsafe(tree, br); |
| 167 } else { |
| 168 const HuffmanTreeNode* node = tree->root_; |
| 169 assert(node != NULL); |
| 170 while (!HuffmanTreeNodeIsLeaf(node)) { |
| 171 node = HuffmanTreeNextNode(node, VP8LReadOneBit(br)); |
| 172 } |
| 173 return node->symbol_; |
| 174 } |
| 175 } |
| 176 |
| 177 static int ReadHuffmanCodeLengths( |
| 178 VP8LDecoder* const dec, const int* const code_length_code_lengths, |
| 179 int num_symbols, int* const code_lengths) { |
| 180 int ok = 0; |
| 181 VP8LBitReader* const br = &dec->br_; |
| 182 int symbol; |
| 183 int max_symbol; |
| 184 int prev_code_len = DEFAULT_CODE_LENGTH; |
| 185 HuffmanTree tree; |
| 186 |
| 187 if (!HuffmanTreeBuildImplicit(&tree, code_length_code_lengths, |
| 188 NUM_CODE_LENGTH_CODES)) { |
| 189 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 190 return 0; |
| 191 } |
| 192 |
| 193 if (VP8LReadBits(br, 1)) { // use length |
| 194 const int length_nbits = 2 + 2 * VP8LReadBits(br, 3); |
| 195 max_symbol = 2 + VP8LReadBits(br, length_nbits); |
| 196 if (max_symbol > num_symbols) { |
| 197 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 198 goto End; |
| 199 } |
| 200 } else { |
| 201 max_symbol = num_symbols; |
| 202 } |
| 203 |
| 204 symbol = 0; |
| 205 while (symbol < num_symbols) { |
| 206 int code_len; |
| 207 if (max_symbol-- == 0) break; |
| 208 VP8LFillBitWindow(br); |
| 209 code_len = ReadSymbol(&tree, br); |
| 210 if (code_len < kCodeLengthLiterals) { |
| 211 code_lengths[symbol++] = code_len; |
| 212 if (code_len != 0) prev_code_len = code_len; |
| 213 } else { |
| 214 const int use_prev = (code_len == kCodeLengthRepeatCode); |
| 215 const int slot = code_len - kCodeLengthLiterals; |
| 216 const int extra_bits = kCodeLengthExtraBits[slot]; |
| 217 const int repeat_offset = kCodeLengthRepeatOffsets[slot]; |
| 218 int repeat = VP8LReadBits(br, extra_bits) + repeat_offset; |
| 219 if (symbol + repeat > num_symbols) { |
| 220 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 221 goto End; |
| 222 } else { |
| 223 const int length = use_prev ? prev_code_len : 0; |
| 224 while (repeat-- > 0) code_lengths[symbol++] = length; |
| 225 } |
| 226 } |
| 227 } |
| 228 ok = 1; |
| 229 |
| 230 End: |
| 231 HuffmanTreeRelease(&tree); |
| 232 return ok; |
| 233 } |
| 234 |
| 235 static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec, |
| 236 HuffmanTree* const tree) { |
| 237 int ok = 0; |
| 238 VP8LBitReader* const br = &dec->br_; |
| 239 const int simple_code = VP8LReadBits(br, 1); |
| 240 |
| 241 if (simple_code) { // Read symbols, codes & code lengths directly. |
| 242 int symbols[2]; |
| 243 int codes[2]; |
| 244 int code_lengths[2]; |
| 245 const int num_symbols = VP8LReadBits(br, 1) + 1; |
| 246 const int first_symbol_len_code = VP8LReadBits(br, 1); |
| 247 // The first code is either 1 bit or 8 bit code. |
| 248 symbols[0] = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8); |
| 249 codes[0] = 0; |
| 250 code_lengths[0] = num_symbols - 1; |
| 251 // The second code (if present), is always 8 bit long. |
| 252 if (num_symbols == 2) { |
| 253 symbols[1] = VP8LReadBits(br, 8); |
| 254 codes[1] = 1; |
| 255 code_lengths[1] = num_symbols - 1; |
| 256 } |
| 257 ok = HuffmanTreeBuildExplicit(tree, code_lengths, codes, symbols, |
| 258 alphabet_size, num_symbols); |
| 259 } else { // Decode Huffman-coded code lengths. |
| 260 int* code_lengths = NULL; |
| 261 int i; |
| 262 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 }; |
| 263 const int num_codes = VP8LReadBits(br, 4) + 4; |
| 264 if (num_codes > NUM_CODE_LENGTH_CODES) { |
| 265 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 266 return 0; |
| 267 } |
| 268 |
| 269 code_lengths = |
| 270 (int*)WebPSafeCalloc((uint64_t)alphabet_size, sizeof(*code_lengths)); |
| 271 if (code_lengths == NULL) { |
| 272 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; |
| 273 return 0; |
| 274 } |
| 275 |
| 276 for (i = 0; i < num_codes; ++i) { |
| 277 code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3); |
| 278 } |
| 279 ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size, |
| 280 code_lengths); |
| 281 if (ok) { |
| 282 ok = HuffmanTreeBuildImplicit(tree, code_lengths, alphabet_size); |
| 283 } |
| 284 free(code_lengths); |
| 285 } |
| 286 ok = ok && !br->error_; |
| 287 if (!ok) { |
| 288 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 289 return 0; |
| 290 } |
| 291 return 1; |
| 292 } |
| 293 |
| 294 static void DeleteHtreeGroups(HTreeGroup* htree_groups, int num_htree_groups) { |
| 295 if (htree_groups != NULL) { |
| 296 int i, j; |
| 297 for (i = 0; i < num_htree_groups; ++i) { |
| 298 HuffmanTree* const htrees = htree_groups[i].htrees_; |
| 299 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { |
| 300 HuffmanTreeRelease(&htrees[j]); |
| 301 } |
| 302 } |
| 303 free(htree_groups); |
| 304 } |
| 305 } |
| 306 |
| 307 static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, |
| 308 int color_cache_bits, int allow_recursion) { |
| 309 int i, j; |
| 310 VP8LBitReader* const br = &dec->br_; |
| 311 VP8LMetadata* const hdr = &dec->hdr_; |
| 312 uint32_t* huffman_image = NULL; |
| 313 HTreeGroup* htree_groups = NULL; |
| 314 int num_htree_groups = 1; |
| 315 |
| 316 if (allow_recursion && VP8LReadBits(br, 1)) { |
| 317 // use meta Huffman codes. |
| 318 const int huffman_precision = VP8LReadBits(br, 3) + 2; |
| 319 const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision); |
| 320 const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision); |
| 321 const int huffman_pixs = huffman_xsize * huffman_ysize; |
| 322 if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec, |
| 323 &huffman_image)) { |
| 324 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 325 goto Error; |
| 326 } |
| 327 hdr->huffman_subsample_bits_ = huffman_precision; |
| 328 for (i = 0; i < huffman_pixs; ++i) { |
| 329 // The huffman data is stored in red and green bytes. |
| 330 const int index = (huffman_image[i] >> 8) & 0xffff; |
| 331 huffman_image[i] = index; |
| 332 if (index >= num_htree_groups) { |
| 333 num_htree_groups = index + 1; |
| 334 } |
| 335 } |
| 336 } |
| 337 |
| 338 if (br->error_) goto Error; |
| 339 |
| 340 assert(num_htree_groups <= 0x10000); |
| 341 htree_groups = |
| 342 (HTreeGroup*)WebPSafeCalloc((uint64_t)num_htree_groups, |
| 343 sizeof(*htree_groups)); |
| 344 if (htree_groups == NULL) { |
| 345 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; |
| 346 goto Error; |
| 347 } |
| 348 |
| 349 for (i = 0; i < num_htree_groups; ++i) { |
| 350 HuffmanTree* const htrees = htree_groups[i].htrees_; |
| 351 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { |
| 352 int alphabet_size = kAlphabetSize[j]; |
| 353 if (j == 0 && color_cache_bits > 0) { |
| 354 alphabet_size += 1 << color_cache_bits; |
| 355 } |
| 356 if (!ReadHuffmanCode(alphabet_size, dec, htrees + j)) goto Error; |
| 357 } |
| 358 } |
| 359 |
| 360 // All OK. Finalize pointers and return. |
| 361 hdr->huffman_image_ = huffman_image; |
| 362 hdr->num_htree_groups_ = num_htree_groups; |
| 363 hdr->htree_groups_ = htree_groups; |
| 364 return 1; |
| 365 |
| 366 Error: |
| 367 free(huffman_image); |
| 368 DeleteHtreeGroups(htree_groups, num_htree_groups); |
| 369 return 0; |
| 370 } |
| 371 |
| 372 //------------------------------------------------------------------------------ |
| 373 // Scaling. |
| 374 |
| 375 static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) { |
| 376 const int num_channels = 4; |
| 377 const int in_width = io->mb_w; |
| 378 const int out_width = io->scaled_width; |
| 379 const int in_height = io->mb_h; |
| 380 const int out_height = io->scaled_height; |
| 381 const uint64_t work_size = 2 * num_channels * (uint64_t)out_width; |
| 382 int32_t* work; // Rescaler work area. |
| 383 const uint64_t scaled_data_size = num_channels * (uint64_t)out_width; |
| 384 uint32_t* scaled_data; // Temporary storage for scaled BGRA data. |
| 385 const uint64_t memory_size = sizeof(*dec->rescaler) + |
| 386 work_size * sizeof(*work) + |
| 387 scaled_data_size * sizeof(*scaled_data); |
| 388 uint8_t* memory = (uint8_t*)WebPSafeCalloc(memory_size, sizeof(*memory)); |
| 389 if (memory == NULL) { |
| 390 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; |
| 391 return 0; |
| 392 } |
| 393 assert(dec->rescaler_memory == NULL); |
| 394 dec->rescaler_memory = memory; |
| 395 |
| 396 dec->rescaler = (WebPRescaler*)memory; |
| 397 memory += sizeof(*dec->rescaler); |
| 398 work = (int32_t*)memory; |
| 399 memory += work_size * sizeof(*work); |
| 400 scaled_data = (uint32_t*)memory; |
| 401 |
| 402 WebPRescalerInit(dec->rescaler, in_width, in_height, (uint8_t*)scaled_data, |
| 403 out_width, out_height, 0, num_channels, |
| 404 in_width, out_width, in_height, out_height, work); |
| 405 return 1; |
| 406 } |
| 407 |
| 408 //------------------------------------------------------------------------------ |
| 409 // Export to ARGB |
| 410 |
| 411 // We have special "export" function since we need to convert from BGRA |
| 412 static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace, |
| 413 int rgba_stride, uint8_t* const rgba) { |
| 414 const uint32_t* const src = (const uint32_t*)rescaler->dst; |
| 415 const int dst_width = rescaler->dst_width; |
| 416 int num_lines_out = 0; |
| 417 while (WebPRescalerHasPendingOutput(rescaler)) { |
| 418 uint8_t* const dst = rgba + num_lines_out * rgba_stride; |
| 419 WebPRescalerExportRow(rescaler); |
| 420 VP8LConvertFromBGRA(src, dst_width, colorspace, dst); |
| 421 ++num_lines_out; |
| 422 } |
| 423 return num_lines_out; |
| 424 } |
| 425 |
| 426 // Emit scaled rows. |
| 427 static int EmitRescaledRows(const VP8LDecoder* const dec, |
| 428 const uint32_t* const data, int in_stride, int mb_h, |
| 429 uint8_t* const out, int out_stride) { |
| 430 const WEBP_CSP_MODE colorspace = dec->output_->colorspace; |
| 431 const uint8_t* const in = (const uint8_t*)data; |
| 432 int num_lines_in = 0; |
| 433 int num_lines_out = 0; |
| 434 while (num_lines_in < mb_h) { |
| 435 const uint8_t* const row_in = in + num_lines_in * in_stride; |
| 436 uint8_t* const row_out = out + num_lines_out * out_stride; |
| 437 num_lines_in += WebPRescalerImport(dec->rescaler, mb_h - num_lines_in, |
| 438 row_in, in_stride); |
| 439 num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out); |
| 440 } |
| 441 return num_lines_out; |
| 442 } |
| 443 |
| 444 // Emit rows without any scaling. |
| 445 static int EmitRows(WEBP_CSP_MODE colorspace, |
| 446 const uint32_t* const data, int in_stride, |
| 447 int mb_w, int mb_h, |
| 448 uint8_t* const out, int out_stride) { |
| 449 int lines = mb_h; |
| 450 const uint8_t* row_in = (const uint8_t*)data; |
| 451 uint8_t* row_out = out; |
| 452 while (lines-- > 0) { |
| 453 VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out); |
| 454 row_in += in_stride; |
| 455 row_out += out_stride; |
| 456 } |
| 457 return mb_h; // Num rows out == num rows in. |
| 458 } |
| 459 |
| 460 //------------------------------------------------------------------------------ |
| 461 // Export to YUVA |
| 462 |
| 463 static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos, |
| 464 const WebPDecBuffer* const output) { |
| 465 const WebPYUVABuffer* const buf = &output->u.YUVA; |
| 466 // first, the luma plane |
| 467 { |
| 468 int i; |
| 469 uint8_t* const y = buf->y + y_pos * buf->y_stride; |
| 470 for (i = 0; i < width; ++i) { |
| 471 const uint32_t p = src[i]; |
| 472 y[i] = VP8RGBToY((p >> 16) & 0xff, (p >> 8) & 0xff, (p >> 0) & 0xff); |
| 473 } |
| 474 } |
| 475 |
| 476 // then U/V planes |
| 477 { |
| 478 uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride; |
| 479 uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride; |
| 480 const int uv_width = width >> 1; |
| 481 int i; |
| 482 for (i = 0; i < uv_width; ++i) { |
| 483 const uint32_t v0 = src[2 * i + 0]; |
| 484 const uint32_t v1 = src[2 * i + 1]; |
| 485 // VP8RGBToU/V expects four accumulated pixels. Hence we need to |
| 486 // scale r/g/b value by a factor 2. We just shift v0/v1 one bit less. |
| 487 const int r = ((v0 >> 15) & 0x1fe) + ((v1 >> 15) & 0x1fe); |
| 488 const int g = ((v0 >> 7) & 0x1fe) + ((v1 >> 7) & 0x1fe); |
| 489 const int b = ((v0 << 1) & 0x1fe) + ((v1 << 1) & 0x1fe); |
| 490 if (!(y_pos & 1)) { // even lines: store values |
| 491 u[i] = VP8RGBToU(r, g, b); |
| 492 v[i] = VP8RGBToV(r, g, b); |
| 493 } else { // odd lines: average with previous values |
| 494 const int tmp_u = VP8RGBToU(r, g, b); |
| 495 const int tmp_v = VP8RGBToV(r, g, b); |
| 496 // Approximated average-of-four. But it's an acceptable diff. |
| 497 u[i] = (u[i] + tmp_u + 1) >> 1; |
| 498 v[i] = (v[i] + tmp_v + 1) >> 1; |
| 499 } |
| 500 } |
| 501 if (width & 1) { // last pixel |
| 502 const uint32_t v0 = src[2 * i + 0]; |
| 503 const int r = (v0 >> 14) & 0x3fc; |
| 504 const int g = (v0 >> 6) & 0x3fc; |
| 505 const int b = (v0 << 2) & 0x3fc; |
| 506 if (!(y_pos & 1)) { // even lines |
| 507 u[i] = VP8RGBToU(r, g, b); |
| 508 v[i] = VP8RGBToV(r, g, b); |
| 509 } else { // odd lines (note: we could just skip this) |
| 510 const int tmp_u = VP8RGBToU(r, g, b); |
| 511 const int tmp_v = VP8RGBToV(r, g, b); |
| 512 u[i] = (u[i] + tmp_u + 1) >> 1; |
| 513 v[i] = (v[i] + tmp_v + 1) >> 1; |
| 514 } |
| 515 } |
| 516 } |
| 517 // Lastly, store alpha if needed. |
| 518 if (buf->a != NULL) { |
| 519 int i; |
| 520 uint8_t* const a = buf->a + y_pos * buf->a_stride; |
| 521 for (i = 0; i < width; ++i) a[i] = (src[i] >> 24); |
| 522 } |
| 523 } |
| 524 |
| 525 static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) { |
| 526 WebPRescaler* const rescaler = dec->rescaler; |
| 527 const uint32_t* const src = (const uint32_t*)rescaler->dst; |
| 528 const int dst_width = rescaler->dst_width; |
| 529 int num_lines_out = 0; |
| 530 while (WebPRescalerHasPendingOutput(rescaler)) { |
| 531 WebPRescalerExportRow(rescaler); |
| 532 ConvertToYUVA(src, dst_width, y_pos, dec->output_); |
| 533 ++y_pos; |
| 534 ++num_lines_out; |
| 535 } |
| 536 return num_lines_out; |
| 537 } |
| 538 |
| 539 static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec, |
| 540 const uint32_t* const data, |
| 541 int in_stride, int mb_h) { |
| 542 const uint8_t* const in = (const uint8_t*)data; |
| 543 int num_lines_in = 0; |
| 544 int y_pos = dec->last_out_row_; |
| 545 while (num_lines_in < mb_h) { |
| 546 const uint8_t* const row_in = in + num_lines_in * in_stride; |
| 547 num_lines_in += WebPRescalerImport(dec->rescaler, mb_h - num_lines_in, |
| 548 row_in, in_stride); |
| 549 y_pos += ExportYUVA(dec, y_pos); |
| 550 } |
| 551 return y_pos; |
| 552 } |
| 553 |
| 554 static int EmitRowsYUVA(const VP8LDecoder* const dec, |
| 555 const uint32_t* const data, int in_stride, |
| 556 int mb_w, int num_rows) { |
| 557 int y_pos = dec->last_out_row_; |
| 558 const uint8_t* row_in = (const uint8_t*)data; |
| 559 while (num_rows-- > 0) { |
| 560 ConvertToYUVA((const uint32_t*)row_in, mb_w, y_pos, dec->output_); |
| 561 row_in += in_stride; |
| 562 ++y_pos; |
| 563 } |
| 564 return y_pos; |
| 565 } |
| 566 |
| 567 //------------------------------------------------------------------------------ |
| 568 // Cropping. |
| 569 |
| 570 // Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and |
| 571 // crop options. Also updates the input data pointer, so that it points to the |
| 572 // start of the cropped window. |
| 573 // Note that 'pixel_stride' is in units of 'uint32_t' (and not 'bytes). |
| 574 // Returns true if the crop window is not empty. |
| 575 static int SetCropWindow(VP8Io* const io, int y_start, int y_end, |
| 576 const uint32_t** const in_data, int pixel_stride) { |
| 577 assert(y_start < y_end); |
| 578 assert(io->crop_left < io->crop_right); |
| 579 if (y_end > io->crop_bottom) { |
| 580 y_end = io->crop_bottom; // make sure we don't overflow on last row. |
| 581 } |
| 582 if (y_start < io->crop_top) { |
| 583 const int delta = io->crop_top - y_start; |
| 584 y_start = io->crop_top; |
| 585 *in_data += pixel_stride * delta; |
| 586 } |
| 587 if (y_start >= y_end) return 0; // Crop window is empty. |
| 588 |
| 589 *in_data += io->crop_left; |
| 590 |
| 591 io->mb_y = y_start - io->crop_top; |
| 592 io->mb_w = io->crop_right - io->crop_left; |
| 593 io->mb_h = y_end - y_start; |
| 594 return 1; // Non-empty crop window. |
| 595 } |
| 596 |
| 597 //------------------------------------------------------------------------------ |
| 598 |
| 599 static WEBP_INLINE int GetMetaIndex( |
| 600 const uint32_t* const image, int xsize, int bits, int x, int y) { |
| 601 if (bits == 0) return 0; |
| 602 return image[xsize * (y >> bits) + (x >> bits)]; |
| 603 } |
| 604 |
| 605 static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr, |
| 606 int x, int y) { |
| 607 const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_, |
| 608 hdr->huffman_subsample_bits_, x, y); |
| 609 assert(meta_index < hdr->num_htree_groups_); |
| 610 return hdr->htree_groups_ + meta_index; |
| 611 } |
| 612 |
| 613 //------------------------------------------------------------------------------ |
| 614 // Main loop, with custom row-processing function |
| 615 |
| 616 typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row); |
| 617 |
| 618 static void ApplyTransforms(VP8LDecoder* const dec, int num_rows, |
| 619 const uint32_t* const rows) { |
| 620 int n = dec->next_transform_; |
| 621 const int cache_pixs = dec->width_ * num_rows; |
| 622 uint32_t* rows_data = dec->argb_cache_; |
| 623 const int start_row = dec->last_row_; |
| 624 const int end_row = start_row + num_rows; |
| 625 |
| 626 // Inverse transforms. |
| 627 // TODO: most transforms only need to operate on the cropped region only. |
| 628 memcpy(rows_data, rows, cache_pixs * sizeof(*rows_data)); |
| 629 while (n-- > 0) { |
| 630 VP8LTransform* const transform = &dec->transforms_[n]; |
| 631 VP8LInverseTransform(transform, start_row, end_row, rows, rows_data); |
| 632 } |
| 633 } |
| 634 |
| 635 // Processes (transforms, scales & color-converts) the rows decoded after the |
| 636 // last call. |
| 637 static void ProcessRows(VP8LDecoder* const dec, int row) { |
| 638 const uint32_t* const rows = dec->argb_ + dec->width_ * dec->last_row_; |
| 639 const int num_rows = row - dec->last_row_; |
| 640 |
| 641 if (num_rows <= 0) return; // Nothing to be done. |
| 642 ApplyTransforms(dec, num_rows, rows); |
| 643 |
| 644 // Emit output. |
| 645 { |
| 646 VP8Io* const io = dec->io_; |
| 647 const uint32_t* rows_data = dec->argb_cache_; |
| 648 if (!SetCropWindow(io, dec->last_row_, row, &rows_data, io->width)) { |
| 649 // Nothing to output (this time). |
| 650 } else { |
| 651 const WebPDecBuffer* const output = dec->output_; |
| 652 const int in_stride = io->width * sizeof(*rows_data); |
| 653 if (output->colorspace < MODE_YUV) { // convert to RGBA |
| 654 const WebPRGBABuffer* const buf = &output->u.RGBA; |
| 655 uint8_t* const rgba = buf->rgba + dec->last_out_row_ * buf->stride; |
| 656 const int num_rows_out = io->use_scaling ? |
| 657 EmitRescaledRows(dec, rows_data, in_stride, io->mb_h, |
| 658 rgba, buf->stride) : |
| 659 EmitRows(output->colorspace, rows_data, in_stride, |
| 660 io->mb_w, io->mb_h, rgba, buf->stride); |
| 661 // Update 'last_out_row_'. |
| 662 dec->last_out_row_ += num_rows_out; |
| 663 } else { // convert to YUVA |
| 664 dec->last_out_row_ = io->use_scaling ? |
| 665 EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) : |
| 666 EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h); |
| 667 } |
| 668 assert(dec->last_out_row_ <= output->height); |
| 669 } |
| 670 } |
| 671 |
| 672 // Update 'last_row_'. |
| 673 dec->last_row_ = row; |
| 674 assert(dec->last_row_ <= dec->height_); |
| 675 } |
| 676 |
| 677 static int DecodeImageData(VP8LDecoder* const dec, |
| 678 uint32_t* const data, int width, int height, |
| 679 ProcessRowsFunc process_func) { |
| 680 int ok = 1; |
| 681 int col = 0, row = 0; |
| 682 VP8LBitReader* const br = &dec->br_; |
| 683 VP8LMetadata* const hdr = &dec->hdr_; |
| 684 HTreeGroup* htree_group = hdr->htree_groups_; |
| 685 uint32_t* src = data; |
| 686 uint32_t* last_cached = data; |
| 687 uint32_t* const src_end = data + width * height; |
| 688 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES; |
| 689 const int color_cache_limit = len_code_limit + hdr->color_cache_size_; |
| 690 VP8LColorCache* const color_cache = |
| 691 (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL; |
| 692 const int mask = hdr->huffman_mask_; |
| 693 |
| 694 assert(htree_group != NULL); |
| 695 |
| 696 while (!br->eos_ && src < src_end) { |
| 697 int code; |
| 698 // Only update when changing tile. Note we could use the following test: |
| 699 // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed |
| 700 // but that's actually slower and requires storing the previous col/row |
| 701 if ((col & mask) == 0) { |
| 702 htree_group = GetHtreeGroupForPos(hdr, col, row); |
| 703 } |
| 704 VP8LFillBitWindow(br); |
| 705 code = ReadSymbol(&htree_group->htrees_[GREEN], br); |
| 706 if (code < NUM_LITERAL_CODES) { // Literal. |
| 707 int red, green, blue, alpha; |
| 708 red = ReadSymbol(&htree_group->htrees_[RED], br); |
| 709 green = code; |
| 710 VP8LFillBitWindow(br); |
| 711 blue = ReadSymbol(&htree_group->htrees_[BLUE], br); |
| 712 alpha = ReadSymbol(&htree_group->htrees_[ALPHA], br); |
| 713 *src = (alpha << 24) + (red << 16) + (green << 8) + blue; |
| 714 AdvanceByOne: |
| 715 ++src; |
| 716 ++col; |
| 717 if (col >= width) { |
| 718 col = 0; |
| 719 ++row; |
| 720 if ((process_func != NULL) && (row % NUM_ARGB_CACHE_ROWS == 0)) { |
| 721 process_func(dec, row); |
| 722 } |
| 723 if (color_cache != NULL) { |
| 724 while (last_cached < src) { |
| 725 VP8LColorCacheInsert(color_cache, *last_cached++); |
| 726 } |
| 727 } |
| 728 } |
| 729 } else if (code < len_code_limit) { // Backward reference |
| 730 int dist_code, dist; |
| 731 const int length_sym = code - NUM_LITERAL_CODES; |
| 732 const int length = GetCopyLength(length_sym, br); |
| 733 const int dist_symbol = ReadSymbol(&htree_group->htrees_[DIST], br); |
| 734 VP8LFillBitWindow(br); |
| 735 dist_code = GetCopyDistance(dist_symbol, br); |
| 736 dist = PlaneCodeToDistance(width, dist_code); |
| 737 if (src - data < dist || src_end - src < length) { |
| 738 ok = 0; |
| 739 goto End; |
| 740 } |
| 741 { |
| 742 int i; |
| 743 for (i = 0; i < length; ++i) src[i] = src[i - dist]; |
| 744 src += length; |
| 745 } |
| 746 col += length; |
| 747 while (col >= width) { |
| 748 col -= width; |
| 749 ++row; |
| 750 if ((process_func != NULL) && (row % NUM_ARGB_CACHE_ROWS == 0)) { |
| 751 process_func(dec, row); |
| 752 } |
| 753 } |
| 754 if (src < src_end) { |
| 755 htree_group = GetHtreeGroupForPos(hdr, col, row); |
| 756 if (color_cache != NULL) { |
| 757 while (last_cached < src) { |
| 758 VP8LColorCacheInsert(color_cache, *last_cached++); |
| 759 } |
| 760 } |
| 761 } |
| 762 } else if (code < color_cache_limit) { // Color cache. |
| 763 const int key = code - len_code_limit; |
| 764 assert(color_cache != NULL); |
| 765 while (last_cached < src) { |
| 766 VP8LColorCacheInsert(color_cache, *last_cached++); |
| 767 } |
| 768 *src = VP8LColorCacheLookup(color_cache, key); |
| 769 goto AdvanceByOne; |
| 770 } else { // Not reached. |
| 771 ok = 0; |
| 772 goto End; |
| 773 } |
| 774 ok = !br->error_; |
| 775 if (!ok) goto End; |
| 776 } |
| 777 // Process the remaining rows corresponding to last row-block. |
| 778 if (process_func != NULL) process_func(dec, row); |
| 779 |
| 780 End: |
| 781 if (br->error_ || !ok || (br->eos_ && src < src_end)) { |
| 782 ok = 0; |
| 783 dec->status_ = (!br->eos_) ? |
| 784 VP8_STATUS_BITSTREAM_ERROR : VP8_STATUS_SUSPENDED; |
| 785 } else if (src == src_end) { |
| 786 dec->state_ = READ_DATA; |
| 787 } |
| 788 |
| 789 return ok; |
| 790 } |
| 791 |
| 792 // ----------------------------------------------------------------------------- |
| 793 // VP8LTransform |
| 794 |
| 795 static void ClearTransform(VP8LTransform* const transform) { |
| 796 free(transform->data_); |
| 797 transform->data_ = NULL; |
| 798 } |
| 799 |
| 800 static void ApplyInverseTransforms(VP8LDecoder* const dec, int start_idx, |
| 801 uint32_t* const decoded_data) { |
| 802 int n = dec->next_transform_; |
| 803 assert(start_idx >= 0); |
| 804 while (n-- > start_idx) { |
| 805 VP8LTransform* const transform = &dec->transforms_[n]; |
| 806 VP8LInverseTransform(transform, 0, transform->ysize_, |
| 807 decoded_data, decoded_data); |
| 808 ClearTransform(transform); |
| 809 } |
| 810 dec->next_transform_ = start_idx; |
| 811 } |
| 812 |
| 813 // For security reason, we need to remap the color map to span |
| 814 // the total possible bundled values, and not just the num_colors. |
| 815 static int ExpandColorMap(int num_colors, VP8LTransform* const transform) { |
| 816 int i; |
| 817 const int final_num_colors = 1 << (8 >> transform->bits_); |
| 818 uint32_t* const new_color_map = |
| 819 (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors, |
| 820 sizeof(*new_color_map)); |
| 821 if (new_color_map == NULL) { |
| 822 return 0; |
| 823 } else { |
| 824 uint8_t* const data = (uint8_t*)transform->data_; |
| 825 uint8_t* const new_data = (uint8_t*)new_color_map; |
| 826 new_color_map[0] = transform->data_[0]; |
| 827 for (i = 4; i < 4 * num_colors; ++i) { |
| 828 // Equivalent to AddPixelEq(), on a byte-basis. |
| 829 new_data[i] = (data[i] + new_data[i - 4]) & 0xff; |
| 830 } |
| 831 for (; i < 4 * final_num_colors; ++i) |
| 832 new_data[i] = 0; // black tail. |
| 833 free(transform->data_); |
| 834 transform->data_ = new_color_map; |
| 835 } |
| 836 return 1; |
| 837 } |
| 838 |
| 839 static int ReadTransform(int* const xsize, int const* ysize, |
| 840 VP8LDecoder* const dec) { |
| 841 int ok = 1; |
| 842 VP8LBitReader* const br = &dec->br_; |
| 843 VP8LTransform* transform = &dec->transforms_[dec->next_transform_]; |
| 844 const VP8LImageTransformType type = |
| 845 (VP8LImageTransformType)VP8LReadBits(br, 2); |
| 846 |
| 847 // Each transform type can only be present once in the stream. |
| 848 if (dec->transforms_seen_ & (1U << type)) { |
| 849 return 0; // Already there, let's not accept the second same transform. |
| 850 } |
| 851 dec->transforms_seen_ |= (1U << type); |
| 852 |
| 853 transform->type_ = type; |
| 854 transform->xsize_ = *xsize; |
| 855 transform->ysize_ = *ysize; |
| 856 transform->data_ = NULL; |
| 857 ++dec->next_transform_; |
| 858 assert(dec->next_transform_ <= NUM_TRANSFORMS); |
| 859 |
| 860 switch (type) { |
| 861 case PREDICTOR_TRANSFORM: |
| 862 case CROSS_COLOR_TRANSFORM: |
| 863 transform->bits_ = VP8LReadBits(br, 3) + 2; |
| 864 ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_, |
| 865 transform->bits_), |
| 866 VP8LSubSampleSize(transform->ysize_, |
| 867 transform->bits_), |
| 868 0, dec, &transform->data_); |
| 869 break; |
| 870 case COLOR_INDEXING_TRANSFORM: { |
| 871 const int num_colors = VP8LReadBits(br, 8) + 1; |
| 872 const int bits = (num_colors > 16) ? 0 |
| 873 : (num_colors > 4) ? 1 |
| 874 : (num_colors > 2) ? 2 |
| 875 : 3; |
| 876 *xsize = VP8LSubSampleSize(transform->xsize_, bits); |
| 877 transform->bits_ = bits; |
| 878 ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_); |
| 879 ok = ok && ExpandColorMap(num_colors, transform); |
| 880 break; |
| 881 } |
| 882 case SUBTRACT_GREEN: |
| 883 break; |
| 884 default: |
| 885 assert(0); // can't happen |
| 886 break; |
| 887 } |
| 888 |
| 889 return ok; |
| 890 } |
| 891 |
| 892 // ----------------------------------------------------------------------------- |
| 893 // VP8LMetadata |
| 894 |
| 895 static void InitMetadata(VP8LMetadata* const hdr) { |
| 896 assert(hdr); |
| 897 memset(hdr, 0, sizeof(*hdr)); |
| 898 } |
| 899 |
| 900 static void ClearMetadata(VP8LMetadata* const hdr) { |
| 901 assert(hdr); |
| 902 |
| 903 free(hdr->huffman_image_); |
| 904 DeleteHtreeGroups(hdr->htree_groups_, hdr->num_htree_groups_); |
| 905 VP8LColorCacheClear(&hdr->color_cache_); |
| 906 InitMetadata(hdr); |
| 907 } |
| 908 |
| 909 // ----------------------------------------------------------------------------- |
| 910 // VP8LDecoder |
| 911 |
| 912 VP8LDecoder* VP8LNew(void) { |
| 913 VP8LDecoder* const dec = (VP8LDecoder*)calloc(1, sizeof(*dec)); |
| 914 if (dec == NULL) return NULL; |
| 915 dec->status_ = VP8_STATUS_OK; |
| 916 dec->action_ = READ_DIM; |
| 917 dec->state_ = READ_DIM; |
| 918 return dec; |
| 919 } |
| 920 |
| 921 void VP8LClear(VP8LDecoder* const dec) { |
| 922 int i; |
| 923 if (dec == NULL) return; |
| 924 ClearMetadata(&dec->hdr_); |
| 925 |
| 926 free(dec->argb_); |
| 927 dec->argb_ = NULL; |
| 928 for (i = 0; i < dec->next_transform_; ++i) { |
| 929 ClearTransform(&dec->transforms_[i]); |
| 930 } |
| 931 dec->next_transform_ = 0; |
| 932 dec->transforms_seen_ = 0; |
| 933 |
| 934 free(dec->rescaler_memory); |
| 935 dec->rescaler_memory = NULL; |
| 936 |
| 937 dec->output_ = NULL; // leave no trace behind |
| 938 } |
| 939 |
| 940 void VP8LDelete(VP8LDecoder* const dec) { |
| 941 if (dec != NULL) { |
| 942 VP8LClear(dec); |
| 943 free(dec); |
| 944 } |
| 945 } |
| 946 |
| 947 static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) { |
| 948 VP8LMetadata* const hdr = &dec->hdr_; |
| 949 const int num_bits = hdr->huffman_subsample_bits_; |
| 950 dec->width_ = width; |
| 951 dec->height_ = height; |
| 952 |
| 953 hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits); |
| 954 hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1; |
| 955 } |
| 956 |
| 957 static int DecodeImageStream(int xsize, int ysize, |
| 958 int is_level0, |
| 959 VP8LDecoder* const dec, |
| 960 uint32_t** const decoded_data) { |
| 961 int ok = 1; |
| 962 int transform_xsize = xsize; |
| 963 int transform_ysize = ysize; |
| 964 VP8LBitReader* const br = &dec->br_; |
| 965 VP8LMetadata* const hdr = &dec->hdr_; |
| 966 uint32_t* data = NULL; |
| 967 const int transform_start_idx = dec->next_transform_; |
| 968 int color_cache_bits = 0; |
| 969 |
| 970 // Read the transforms (may recurse). |
| 971 if (is_level0) { |
| 972 while (ok && VP8LReadBits(br, 1)) { |
| 973 ok = ReadTransform(&transform_xsize, &transform_ysize, dec); |
| 974 } |
| 975 } |
| 976 |
| 977 // Color cache |
| 978 if (ok && VP8LReadBits(br, 1)) { |
| 979 color_cache_bits = VP8LReadBits(br, 4); |
| 980 ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS); |
| 981 if (!ok) { |
| 982 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 983 goto End; |
| 984 } |
| 985 } |
| 986 |
| 987 // Read the Huffman codes (may recurse). |
| 988 ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize, |
| 989 color_cache_bits, is_level0); |
| 990 if (!ok) { |
| 991 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 992 goto End; |
| 993 } |
| 994 |
| 995 // Finish setting up the color-cache |
| 996 if (color_cache_bits > 0) { |
| 997 hdr->color_cache_size_ = 1 << color_cache_bits; |
| 998 if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) { |
| 999 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; |
| 1000 ok = 0; |
| 1001 goto End; |
| 1002 } |
| 1003 } else { |
| 1004 hdr->color_cache_size_ = 0; |
| 1005 } |
| 1006 UpdateDecoder(dec, transform_xsize, transform_ysize); |
| 1007 |
| 1008 if (is_level0) { // level 0 complete |
| 1009 dec->state_ = READ_HDR; |
| 1010 goto End; |
| 1011 } |
| 1012 |
| 1013 { |
| 1014 const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize; |
| 1015 data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data)); |
| 1016 if (data == NULL) { |
| 1017 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; |
| 1018 ok = 0; |
| 1019 goto End; |
| 1020 } |
| 1021 } |
| 1022 |
| 1023 // Use the Huffman trees to decode the LZ77 encoded data. |
| 1024 ok = DecodeImageData(dec, data, transform_xsize, transform_ysize, NULL); |
| 1025 ok = ok && !br->error_; |
| 1026 |
| 1027 // Apply transforms on the decoded data. |
| 1028 if (ok) ApplyInverseTransforms(dec, transform_start_idx, data); |
| 1029 |
| 1030 End: |
| 1031 |
| 1032 if (!ok) { |
| 1033 free(data); |
| 1034 ClearMetadata(hdr); |
| 1035 // If not enough data (br.eos_) resulted in BIT_STREAM_ERROR, update the |
| 1036 // status appropriately. |
| 1037 if (dec->status_ == VP8_STATUS_BITSTREAM_ERROR && dec->br_.eos_) { |
| 1038 dec->status_ = VP8_STATUS_SUSPENDED; |
| 1039 } |
| 1040 } else { |
| 1041 if (decoded_data != NULL) { |
| 1042 *decoded_data = data; |
| 1043 } else { |
| 1044 // We allocate image data in this function only for transforms. At level 0 |
| 1045 // (that is: not the transforms), we shouldn't have allocated anything. |
| 1046 assert(data == NULL); |
| 1047 assert(is_level0); |
| 1048 } |
| 1049 if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind. |
| 1050 } |
| 1051 return ok; |
| 1052 } |
| 1053 |
| 1054 //------------------------------------------------------------------------------ |
| 1055 // Allocate dec->argb_ and dec->argb_cache_ using dec->width_ and dec->height_ |
| 1056 |
| 1057 static int AllocateARGBBuffers(VP8LDecoder* const dec, int final_width) { |
| 1058 const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_; |
| 1059 // Scratch buffer corresponding to top-prediction row for transforming the |
| 1060 // first row in the row-blocks. |
| 1061 const uint64_t cache_top_pixels = final_width; |
| 1062 // Scratch buffer for temporary BGRA storage. |
| 1063 const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS; |
| 1064 const uint64_t total_num_pixels = |
| 1065 num_pixels + cache_top_pixels + cache_pixels; |
| 1066 |
| 1067 assert(dec->width_ <= final_width); |
| 1068 dec->argb_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(*dec->argb_)); |
| 1069 if (dec->argb_ == NULL) { |
| 1070 dec->argb_cache_ = NULL; // for sanity check |
| 1071 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; |
| 1072 return 0; |
| 1073 } |
| 1074 dec->argb_cache_ = dec->argb_ + num_pixels + cache_top_pixels; |
| 1075 return 1; |
| 1076 } |
| 1077 |
| 1078 //------------------------------------------------------------------------------ |
| 1079 // Special row-processing that only stores the alpha data. |
| 1080 |
| 1081 static void ExtractAlphaRows(VP8LDecoder* const dec, int row) { |
| 1082 const int num_rows = row - dec->last_row_; |
| 1083 const uint32_t* const in = dec->argb_ + dec->width_ * dec->last_row_; |
| 1084 |
| 1085 if (num_rows <= 0) return; // Nothing to be done. |
| 1086 ApplyTransforms(dec, num_rows, in); |
| 1087 |
| 1088 // Extract alpha (which is stored in the green plane). |
| 1089 { |
| 1090 const int width = dec->io_->width; // the final width (!= dec->width_) |
| 1091 const int cache_pixs = width * num_rows; |
| 1092 uint8_t* const dst = (uint8_t*)dec->io_->opaque + width * dec->last_row_; |
| 1093 const uint32_t* const src = dec->argb_cache_; |
| 1094 int i; |
| 1095 for (i = 0; i < cache_pixs; ++i) dst[i] = (src[i] >> 8) & 0xff; |
| 1096 } |
| 1097 |
| 1098 dec->last_row_ = dec->last_out_row_ = row; |
| 1099 } |
| 1100 |
| 1101 int VP8LDecodeAlphaImageStream(int width, int height, const uint8_t* const data, |
| 1102 size_t data_size, uint8_t* const output) { |
| 1103 VP8Io io; |
| 1104 int ok = 0; |
| 1105 VP8LDecoder* const dec = VP8LNew(); |
| 1106 if (dec == NULL) return 0; |
| 1107 |
| 1108 dec->width_ = width; |
| 1109 dec->height_ = height; |
| 1110 dec->io_ = &io; |
| 1111 |
| 1112 VP8InitIo(&io); |
| 1113 WebPInitCustomIo(NULL, &io); // Just a sanity Init. io won't be used. |
| 1114 io.opaque = output; |
| 1115 io.width = width; |
| 1116 io.height = height; |
| 1117 |
| 1118 dec->status_ = VP8_STATUS_OK; |
| 1119 VP8LInitBitReader(&dec->br_, data, data_size); |
| 1120 |
| 1121 dec->action_ = READ_HDR; |
| 1122 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Err; |
| 1123 |
| 1124 // Allocate output (note that dec->width_ may have changed here). |
| 1125 if (!AllocateARGBBuffers(dec, width)) goto Err; |
| 1126 |
| 1127 // Decode (with special row processing). |
| 1128 dec->action_ = READ_DATA; |
| 1129 ok = DecodeImageData(dec, dec->argb_, dec->width_, dec->height_, |
| 1130 ExtractAlphaRows); |
| 1131 |
| 1132 Err: |
| 1133 VP8LDelete(dec); |
| 1134 return ok; |
| 1135 } |
| 1136 |
| 1137 //------------------------------------------------------------------------------ |
| 1138 |
| 1139 int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) { |
| 1140 int width, height, has_alpha; |
| 1141 |
| 1142 if (dec == NULL) return 0; |
| 1143 if (io == NULL) { |
| 1144 dec->status_ = VP8_STATUS_INVALID_PARAM; |
| 1145 return 0; |
| 1146 } |
| 1147 |
| 1148 dec->io_ = io; |
| 1149 dec->status_ = VP8_STATUS_OK; |
| 1150 VP8LInitBitReader(&dec->br_, io->data, io->data_size); |
| 1151 if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) { |
| 1152 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; |
| 1153 goto Error; |
| 1154 } |
| 1155 dec->state_ = READ_DIM; |
| 1156 io->width = width; |
| 1157 io->height = height; |
| 1158 |
| 1159 dec->action_ = READ_HDR; |
| 1160 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error; |
| 1161 return 1; |
| 1162 |
| 1163 Error: |
| 1164 VP8LClear(dec); |
| 1165 assert(dec->status_ != VP8_STATUS_OK); |
| 1166 return 0; |
| 1167 } |
| 1168 |
| 1169 int VP8LDecodeImage(VP8LDecoder* const dec) { |
| 1170 VP8Io* io = NULL; |
| 1171 WebPDecParams* params = NULL; |
| 1172 |
| 1173 // Sanity checks. |
| 1174 if (dec == NULL) return 0; |
| 1175 |
| 1176 io = dec->io_; |
| 1177 assert(io != NULL); |
| 1178 params = (WebPDecParams*)io->opaque; |
| 1179 assert(params != NULL); |
| 1180 dec->output_ = params->output; |
| 1181 assert(dec->output_ != NULL); |
| 1182 |
| 1183 // Initialization. |
| 1184 if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) { |
| 1185 dec->status_ = VP8_STATUS_INVALID_PARAM; |
| 1186 goto Err; |
| 1187 } |
| 1188 |
| 1189 if (!AllocateARGBBuffers(dec, io->width)) goto Err; |
| 1190 |
| 1191 if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err; |
| 1192 |
| 1193 // Decode. |
| 1194 dec->action_ = READ_DATA; |
| 1195 if (!DecodeImageData(dec, dec->argb_, dec->width_, dec->height_, |
| 1196 ProcessRows)) { |
| 1197 goto Err; |
| 1198 } |
| 1199 |
| 1200 // Cleanup. |
| 1201 params->last_y = dec->last_out_row_; |
| 1202 VP8LClear(dec); |
| 1203 return 1; |
| 1204 |
| 1205 Err: |
| 1206 VP8LClear(dec); |
| 1207 assert(dec->status_ != VP8_STATUS_OK); |
| 1208 return 0; |
| 1209 } |
| 1210 |
| 1211 //------------------------------------------------------------------------------ |
| 1212 |
| 1213 #if defined(__cplusplus) || defined(c_plusplus) |
| 1214 } // extern "C" |
| 1215 #endif |
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