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@gmail.com) 13// Jyrki Alakuijala (jyrki@google.com) 14 15#include <stdlib.h> 16 17#include "./alphai.h" 18#include "./vp8li.h" 19#include "../dsp/dsp.h" 20#include "../dsp/lossless.h" 21#include "../dsp/yuv.h" 22#include "../utils/huffman.h" 23#include "../utils/utils.h" 24 25#define NUM_ARGB_CACHE_ROWS 16 26 27static const int kCodeLengthLiterals = 16; 28static const int kCodeLengthRepeatCode = 16; 29static const int kCodeLengthExtraBits[3] = { 2, 3, 7 }; 30static 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. 39typedef enum { 40 GREEN = 0, 41 RED = 1, 42 BLUE = 2, 43 ALPHA = 3, 44 DIST = 4 45} HuffIndex; 46 47static 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 55static 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 60static const uint8_t kCodeToPlane[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 75static int DecodeImageStream(int xsize, int ysize, 76 int is_level0, 77 VP8LDecoder* const dec, 78 uint32_t** const decoded_data); 79 80//------------------------------------------------------------------------------ 81 82int VP8LCheckSignature(const uint8_t* const data, size_t size) { 83 return (size >= VP8L_FRAME_HEADER_SIZE && 84 data[0] == VP8L_MAGIC_BYTE && 85 (data[4] >> 5) == 0); // version 86} 87 88static int ReadImageInfo(VP8LBitReader* const br, 89 int* const width, int* const height, 90 int* const has_alpha) { 91 if (VP8LReadBits(br, 8) != VP8L_MAGIC_BYTE) return 0; 92 *width = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1; 93 *height = VP8LReadBits(br, VP8L_IMAGE_SIZE_BITS) + 1; 94 *has_alpha = VP8LReadBits(br, 1); 95 if (VP8LReadBits(br, VP8L_VERSION_BITS) != 0) return 0; 96 return 1; 97} 98 99int VP8LGetInfo(const uint8_t* data, size_t data_size, 100 int* const width, int* const height, int* const has_alpha) { 101 if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) { 102 return 0; // not enough data 103 } else if (!VP8LCheckSignature(data, data_size)) { 104 return 0; // bad signature 105 } else { 106 int w, h, a; 107 VP8LBitReader br; 108 VP8LInitBitReader(&br, data, data_size); 109 if (!ReadImageInfo(&br, &w, &h, &a)) { 110 return 0; 111 } 112 if (width != NULL) *width = w; 113 if (height != NULL) *height = h; 114 if (has_alpha != NULL) *has_alpha = a; 115 return 1; 116 } 117} 118 119//------------------------------------------------------------------------------ 120 121static WEBP_INLINE int GetCopyDistance(int distance_symbol, 122 VP8LBitReader* const br) { 123 int extra_bits, offset; 124 if (distance_symbol < 4) { 125 return distance_symbol + 1; 126 } 127 extra_bits = (distance_symbol - 2) >> 1; 128 offset = (2 + (distance_symbol & 1)) << extra_bits; 129 return offset + VP8LReadBits(br, extra_bits) + 1; 130} 131 132static WEBP_INLINE int GetCopyLength(int length_symbol, 133 VP8LBitReader* const br) { 134 // Length and distance prefixes are encoded the same way. 135 return GetCopyDistance(length_symbol, br); 136} 137 138static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) { 139 if (plane_code > CODE_TO_PLANE_CODES) { 140 return plane_code - CODE_TO_PLANE_CODES; 141 } else { 142 const int dist_code = kCodeToPlane[plane_code - 1]; 143 const int yoffset = dist_code >> 4; 144 const int xoffset = 8 - (dist_code & 0xf); 145 const int dist = yoffset * xsize + xoffset; 146 return (dist >= 1) ? dist : 1; // dist<1 can happen if xsize is very small 147 } 148} 149 150//------------------------------------------------------------------------------ 151// Decodes the next Huffman code from bit-stream. 152// FillBitWindow(br) needs to be called at minimum every second call 153// to ReadSymbol, in order to pre-fetch enough bits. 154static WEBP_INLINE int ReadSymbol(const HuffmanTree* tree, 155 VP8LBitReader* const br) { 156 const HuffmanTreeNode* node = tree->root_; 157 uint32_t bits = VP8LPrefetchBits(br); 158 int bitpos = br->bit_pos_; 159 // Check if we find the bit combination from the Huffman lookup table. 160 const int lut_ix = bits & (HUFF_LUT - 1); 161 const int lut_bits = tree->lut_bits_[lut_ix]; 162 if (lut_bits <= HUFF_LUT_BITS) { 163 VP8LSetBitPos(br, bitpos + lut_bits); 164 return tree->lut_symbol_[lut_ix]; 165 } 166 node += tree->lut_jump_[lut_ix]; 167 bitpos += HUFF_LUT_BITS; 168 bits >>= HUFF_LUT_BITS; 169 170 // Decode the value from a binary tree. 171 assert(node != NULL); 172 do { 173 node = HuffmanTreeNextNode(node, bits & 1); 174 bits >>= 1; 175 ++bitpos; 176 } while (HuffmanTreeNodeIsNotLeaf(node)); 177 VP8LSetBitPos(br, bitpos); 178 return node->symbol_; 179} 180 181static int ReadHuffmanCodeLengths( 182 VP8LDecoder* const dec, const int* const code_length_code_lengths, 183 int num_symbols, int* const code_lengths) { 184 int ok = 0; 185 VP8LBitReader* const br = &dec->br_; 186 int symbol; 187 int max_symbol; 188 int prev_code_len = DEFAULT_CODE_LENGTH; 189 HuffmanTree tree; 190 int huff_codes[NUM_CODE_LENGTH_CODES] = { 0 }; 191 192 if (!VP8LHuffmanTreeBuildImplicit(&tree, code_length_code_lengths, 193 huff_codes, NUM_CODE_LENGTH_CODES)) { 194 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 195 return 0; 196 } 197 198 if (VP8LReadBits(br, 1)) { // use length 199 const int length_nbits = 2 + 2 * VP8LReadBits(br, 3); 200 max_symbol = 2 + VP8LReadBits(br, length_nbits); 201 if (max_symbol > num_symbols) { 202 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 203 goto End; 204 } 205 } else { 206 max_symbol = num_symbols; 207 } 208 209 symbol = 0; 210 while (symbol < num_symbols) { 211 int code_len; 212 if (max_symbol-- == 0) break; 213 VP8LFillBitWindow(br); 214 code_len = ReadSymbol(&tree, br); 215 if (code_len < kCodeLengthLiterals) { 216 code_lengths[symbol++] = code_len; 217 if (code_len != 0) prev_code_len = code_len; 218 } else { 219 const int use_prev = (code_len == kCodeLengthRepeatCode); 220 const int slot = code_len - kCodeLengthLiterals; 221 const int extra_bits = kCodeLengthExtraBits[slot]; 222 const int repeat_offset = kCodeLengthRepeatOffsets[slot]; 223 int repeat = VP8LReadBits(br, extra_bits) + repeat_offset; 224 if (symbol + repeat > num_symbols) { 225 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 226 goto End; 227 } else { 228 const int length = use_prev ? prev_code_len : 0; 229 while (repeat-- > 0) code_lengths[symbol++] = length; 230 } 231 } 232 } 233 ok = 1; 234 235 End: 236 VP8LHuffmanTreeFree(&tree); 237 if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 238 return ok; 239} 240 241// 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman 242// tree. 243static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec, 244 int* const code_lengths, int* const huff_codes, 245 HuffmanTree* const tree) { 246 int ok = 0; 247 VP8LBitReader* const br = &dec->br_; 248 const int simple_code = VP8LReadBits(br, 1); 249 250 if (simple_code) { // Read symbols, codes & code lengths directly. 251 int symbols[2]; 252 int codes[2]; 253 const int num_symbols = VP8LReadBits(br, 1) + 1; 254 const int first_symbol_len_code = VP8LReadBits(br, 1); 255 // The first code is either 1 bit or 8 bit code. 256 symbols[0] = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8); 257 codes[0] = 0; 258 code_lengths[0] = num_symbols - 1; 259 // The second code (if present), is always 8 bit long. 260 if (num_symbols == 2) { 261 symbols[1] = VP8LReadBits(br, 8); 262 codes[1] = 1; 263 code_lengths[1] = num_symbols - 1; 264 } 265 ok = VP8LHuffmanTreeBuildExplicit(tree, code_lengths, codes, symbols, 266 alphabet_size, num_symbols); 267 } else { // Decode Huffman-coded code lengths. 268 int i; 269 int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 }; 270 const int num_codes = VP8LReadBits(br, 4) + 4; 271 if (num_codes > NUM_CODE_LENGTH_CODES) { 272 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 273 return 0; 274 } 275 276 memset(code_lengths, 0, alphabet_size * sizeof(*code_lengths)); 277 278 for (i = 0; i < num_codes; ++i) { 279 code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3); 280 } 281 ok = ReadHuffmanCodeLengths(dec, code_length_code_lengths, alphabet_size, 282 code_lengths); 283 ok = ok && VP8LHuffmanTreeBuildImplicit(tree, code_lengths, huff_codes, 284 alphabet_size); 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 294static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, 295 int color_cache_bits, int allow_recursion) { 296 int i, j; 297 VP8LBitReader* const br = &dec->br_; 298 VP8LMetadata* const hdr = &dec->hdr_; 299 uint32_t* huffman_image = NULL; 300 HTreeGroup* htree_groups = NULL; 301 int num_htree_groups = 1; 302 int max_alphabet_size = 0; 303 int* code_lengths = NULL; 304 int* huff_codes = NULL; 305 306 if (allow_recursion && VP8LReadBits(br, 1)) { 307 // use meta Huffman codes. 308 const int huffman_precision = VP8LReadBits(br, 3) + 2; 309 const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision); 310 const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision); 311 const int huffman_pixs = huffman_xsize * huffman_ysize; 312 if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec, 313 &huffman_image)) { 314 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 315 goto Error; 316 } 317 hdr->huffman_subsample_bits_ = huffman_precision; 318 for (i = 0; i < huffman_pixs; ++i) { 319 // The huffman data is stored in red and green bytes. 320 const int group = (huffman_image[i] >> 8) & 0xffff; 321 huffman_image[i] = group; 322 if (group >= num_htree_groups) { 323 num_htree_groups = group + 1; 324 } 325 } 326 } 327 328 if (br->error_) goto Error; 329 330 // Find maximum alphabet size for the htree group. 331 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { 332 int alphabet_size = kAlphabetSize[j]; 333 if (j == 0 && color_cache_bits > 0) { 334 alphabet_size += 1 << color_cache_bits; 335 } 336 if (max_alphabet_size < alphabet_size) { 337 max_alphabet_size = alphabet_size; 338 } 339 } 340 341 htree_groups = VP8LHtreeGroupsNew(num_htree_groups); 342 code_lengths = 343 (int*)WebPSafeCalloc((uint64_t)max_alphabet_size, sizeof(*code_lengths)); 344 huff_codes = 345 (int*)WebPSafeMalloc((uint64_t)max_alphabet_size, sizeof(*huff_codes)); 346 347 if (htree_groups == NULL || code_lengths == NULL || huff_codes == NULL) { 348 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 349 goto Error; 350 } 351 352 for (i = 0; i < num_htree_groups; ++i) { 353 HuffmanTree* const htrees = htree_groups[i].htrees_; 354 for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { 355 int alphabet_size = kAlphabetSize[j]; 356 HuffmanTree* const htree = htrees + j; 357 if (j == 0 && color_cache_bits > 0) { 358 alphabet_size += 1 << color_cache_bits; 359 } 360 if (!ReadHuffmanCode(alphabet_size, dec, code_lengths, huff_codes, 361 htree)) { 362 goto Error; 363 } 364 } 365 } 366 WebPSafeFree(huff_codes); 367 WebPSafeFree(code_lengths); 368 369 // All OK. Finalize pointers and return. 370 hdr->huffman_image_ = huffman_image; 371 hdr->num_htree_groups_ = num_htree_groups; 372 hdr->htree_groups_ = htree_groups; 373 return 1; 374 375 Error: 376 WebPSafeFree(huff_codes); 377 WebPSafeFree(code_lengths); 378 WebPSafeFree(huffman_image); 379 VP8LHtreeGroupsFree(htree_groups, num_htree_groups); 380 return 0; 381} 382 383//------------------------------------------------------------------------------ 384// Scaling. 385 386static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) { 387 const int num_channels = 4; 388 const int in_width = io->mb_w; 389 const int out_width = io->scaled_width; 390 const int in_height = io->mb_h; 391 const int out_height = io->scaled_height; 392 const uint64_t work_size = 2 * num_channels * (uint64_t)out_width; 393 int32_t* work; // Rescaler work area. 394 const uint64_t scaled_data_size = num_channels * (uint64_t)out_width; 395 uint32_t* scaled_data; // Temporary storage for scaled BGRA data. 396 const uint64_t memory_size = sizeof(*dec->rescaler) + 397 work_size * sizeof(*work) + 398 scaled_data_size * sizeof(*scaled_data); 399 uint8_t* memory = (uint8_t*)WebPSafeCalloc(memory_size, sizeof(*memory)); 400 if (memory == NULL) { 401 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 402 return 0; 403 } 404 assert(dec->rescaler_memory == NULL); 405 dec->rescaler_memory = memory; 406 407 dec->rescaler = (WebPRescaler*)memory; 408 memory += sizeof(*dec->rescaler); 409 work = (int32_t*)memory; 410 memory += work_size * sizeof(*work); 411 scaled_data = (uint32_t*)memory; 412 413 WebPRescalerInit(dec->rescaler, in_width, in_height, (uint8_t*)scaled_data, 414 out_width, out_height, 0, num_channels, 415 in_width, out_width, in_height, out_height, work); 416 return 1; 417} 418 419//------------------------------------------------------------------------------ 420// Export to ARGB 421 422// We have special "export" function since we need to convert from BGRA 423static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace, 424 int rgba_stride, uint8_t* const rgba) { 425 uint32_t* const src = (uint32_t*)rescaler->dst; 426 const int dst_width = rescaler->dst_width; 427 int num_lines_out = 0; 428 while (WebPRescalerHasPendingOutput(rescaler)) { 429 uint8_t* const dst = rgba + num_lines_out * rgba_stride; 430 WebPRescalerExportRow(rescaler, 0); 431 WebPMultARGBRow(src, dst_width, 1); 432 VP8LConvertFromBGRA(src, dst_width, colorspace, dst); 433 ++num_lines_out; 434 } 435 return num_lines_out; 436} 437 438// Emit scaled rows. 439static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec, 440 uint8_t* in, int in_stride, int mb_h, 441 uint8_t* const out, int out_stride) { 442 const WEBP_CSP_MODE colorspace = dec->output_->colorspace; 443 int num_lines_in = 0; 444 int num_lines_out = 0; 445 while (num_lines_in < mb_h) { 446 uint8_t* const row_in = in + num_lines_in * in_stride; 447 uint8_t* const row_out = out + num_lines_out * out_stride; 448 const int lines_left = mb_h - num_lines_in; 449 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left); 450 assert(needed_lines > 0 && needed_lines <= lines_left); 451 WebPMultARGBRows(row_in, in_stride, 452 dec->rescaler->src_width, needed_lines, 0); 453 WebPRescalerImport(dec->rescaler, lines_left, row_in, in_stride); 454 num_lines_in += needed_lines; 455 num_lines_out += Export(dec->rescaler, colorspace, out_stride, row_out); 456 } 457 return num_lines_out; 458} 459 460// Emit rows without any scaling. 461static int EmitRows(WEBP_CSP_MODE colorspace, 462 const uint8_t* row_in, int in_stride, 463 int mb_w, int mb_h, 464 uint8_t* const out, int out_stride) { 465 int lines = mb_h; 466 uint8_t* row_out = out; 467 while (lines-- > 0) { 468 VP8LConvertFromBGRA((const uint32_t*)row_in, mb_w, colorspace, row_out); 469 row_in += in_stride; 470 row_out += out_stride; 471 } 472 return mb_h; // Num rows out == num rows in. 473} 474 475//------------------------------------------------------------------------------ 476// Export to YUVA 477 478// TODO(skal): should be in yuv.c 479static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos, 480 const WebPDecBuffer* const output) { 481 const WebPYUVABuffer* const buf = &output->u.YUVA; 482 // first, the luma plane 483 { 484 int i; 485 uint8_t* const y = buf->y + y_pos * buf->y_stride; 486 for (i = 0; i < width; ++i) { 487 const uint32_t p = src[i]; 488 y[i] = VP8RGBToY((p >> 16) & 0xff, (p >> 8) & 0xff, (p >> 0) & 0xff, 489 YUV_HALF); 490 } 491 } 492 493 // then U/V planes 494 { 495 uint8_t* const u = buf->u + (y_pos >> 1) * buf->u_stride; 496 uint8_t* const v = buf->v + (y_pos >> 1) * buf->v_stride; 497 const int uv_width = width >> 1; 498 int i; 499 for (i = 0; i < uv_width; ++i) { 500 const uint32_t v0 = src[2 * i + 0]; 501 const uint32_t v1 = src[2 * i + 1]; 502 // VP8RGBToU/V expects four accumulated pixels. Hence we need to 503 // scale r/g/b value by a factor 2. We just shift v0/v1 one bit less. 504 const int r = ((v0 >> 15) & 0x1fe) + ((v1 >> 15) & 0x1fe); 505 const int g = ((v0 >> 7) & 0x1fe) + ((v1 >> 7) & 0x1fe); 506 const int b = ((v0 << 1) & 0x1fe) + ((v1 << 1) & 0x1fe); 507 if (!(y_pos & 1)) { // even lines: store values 508 u[i] = VP8RGBToU(r, g, b, YUV_HALF << 2); 509 v[i] = VP8RGBToV(r, g, b, YUV_HALF << 2); 510 } else { // odd lines: average with previous values 511 const int tmp_u = VP8RGBToU(r, g, b, YUV_HALF << 2); 512 const int tmp_v = VP8RGBToV(r, g, b, YUV_HALF << 2); 513 // Approximated average-of-four. But it's an acceptable diff. 514 u[i] = (u[i] + tmp_u + 1) >> 1; 515 v[i] = (v[i] + tmp_v + 1) >> 1; 516 } 517 } 518 if (width & 1) { // last pixel 519 const uint32_t v0 = src[2 * i + 0]; 520 const int r = (v0 >> 14) & 0x3fc; 521 const int g = (v0 >> 6) & 0x3fc; 522 const int b = (v0 << 2) & 0x3fc; 523 if (!(y_pos & 1)) { // even lines 524 u[i] = VP8RGBToU(r, g, b, YUV_HALF << 2); 525 v[i] = VP8RGBToV(r, g, b, YUV_HALF << 2); 526 } else { // odd lines (note: we could just skip this) 527 const int tmp_u = VP8RGBToU(r, g, b, YUV_HALF << 2); 528 const int tmp_v = VP8RGBToV(r, g, b, YUV_HALF << 2); 529 u[i] = (u[i] + tmp_u + 1) >> 1; 530 v[i] = (v[i] + tmp_v + 1) >> 1; 531 } 532 } 533 } 534 // Lastly, store alpha if needed. 535 if (buf->a != NULL) { 536 int i; 537 uint8_t* const a = buf->a + y_pos * buf->a_stride; 538 for (i = 0; i < width; ++i) a[i] = (src[i] >> 24); 539 } 540} 541 542static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) { 543 WebPRescaler* const rescaler = dec->rescaler; 544 uint32_t* const src = (uint32_t*)rescaler->dst; 545 const int dst_width = rescaler->dst_width; 546 int num_lines_out = 0; 547 while (WebPRescalerHasPendingOutput(rescaler)) { 548 WebPRescalerExportRow(rescaler, 0); 549 WebPMultARGBRow(src, dst_width, 1); 550 ConvertToYUVA(src, dst_width, y_pos, dec->output_); 551 ++y_pos; 552 ++num_lines_out; 553 } 554 return num_lines_out; 555} 556 557static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec, 558 uint8_t* in, int in_stride, int mb_h) { 559 int num_lines_in = 0; 560 int y_pos = dec->last_out_row_; 561 while (num_lines_in < mb_h) { 562 const int lines_left = mb_h - num_lines_in; 563 const int needed_lines = WebPRescaleNeededLines(dec->rescaler, lines_left); 564 WebPMultARGBRows(in, in_stride, dec->rescaler->src_width, needed_lines, 0); 565 WebPRescalerImport(dec->rescaler, lines_left, in, in_stride); 566 num_lines_in += needed_lines; 567 in += needed_lines * in_stride; 568 y_pos += ExportYUVA(dec, y_pos); 569 } 570 return y_pos; 571} 572 573static int EmitRowsYUVA(const VP8LDecoder* const dec, 574 const uint8_t* in, int in_stride, 575 int mb_w, int num_rows) { 576 int y_pos = dec->last_out_row_; 577 while (num_rows-- > 0) { 578 ConvertToYUVA((const uint32_t*)in, mb_w, y_pos, dec->output_); 579 in += in_stride; 580 ++y_pos; 581 } 582 return y_pos; 583} 584 585//------------------------------------------------------------------------------ 586// Cropping. 587 588// Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and 589// crop options. Also updates the input data pointer, so that it points to the 590// start of the cropped window. Note that pixels are in ARGB format even if 591// 'in_data' is uint8_t*. 592// Returns true if the crop window is not empty. 593static int SetCropWindow(VP8Io* const io, int y_start, int y_end, 594 uint8_t** const in_data, int pixel_stride) { 595 assert(y_start < y_end); 596 assert(io->crop_left < io->crop_right); 597 if (y_end > io->crop_bottom) { 598 y_end = io->crop_bottom; // make sure we don't overflow on last row. 599 } 600 if (y_start < io->crop_top) { 601 const int delta = io->crop_top - y_start; 602 y_start = io->crop_top; 603 *in_data += delta * pixel_stride; 604 } 605 if (y_start >= y_end) return 0; // Crop window is empty. 606 607 *in_data += io->crop_left * sizeof(uint32_t); 608 609 io->mb_y = y_start - io->crop_top; 610 io->mb_w = io->crop_right - io->crop_left; 611 io->mb_h = y_end - y_start; 612 return 1; // Non-empty crop window. 613} 614 615//------------------------------------------------------------------------------ 616 617static WEBP_INLINE int GetMetaIndex( 618 const uint32_t* const image, int xsize, int bits, int x, int y) { 619 if (bits == 0) return 0; 620 return image[xsize * (y >> bits) + (x >> bits)]; 621} 622 623static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr, 624 int x, int y) { 625 const int meta_index = GetMetaIndex(hdr->huffman_image_, hdr->huffman_xsize_, 626 hdr->huffman_subsample_bits_, x, y); 627 assert(meta_index < hdr->num_htree_groups_); 628 return hdr->htree_groups_ + meta_index; 629} 630 631//------------------------------------------------------------------------------ 632// Main loop, with custom row-processing function 633 634typedef void (*ProcessRowsFunc)(VP8LDecoder* const dec, int row); 635 636static void ApplyInverseTransforms(VP8LDecoder* const dec, int num_rows, 637 const uint32_t* const rows) { 638 int n = dec->next_transform_; 639 const int cache_pixs = dec->width_ * num_rows; 640 const int start_row = dec->last_row_; 641 const int end_row = start_row + num_rows; 642 const uint32_t* rows_in = rows; 643 uint32_t* const rows_out = dec->argb_cache_; 644 645 // Inverse transforms. 646 // TODO: most transforms only need to operate on the cropped region only. 647 memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out)); 648 while (n-- > 0) { 649 VP8LTransform* const transform = &dec->transforms_[n]; 650 VP8LInverseTransform(transform, start_row, end_row, rows_in, rows_out); 651 rows_in = rows_out; 652 } 653} 654 655// Special method for paletted alpha data. 656static void ApplyInverseTransformsAlpha(VP8LDecoder* const dec, int num_rows, 657 const uint8_t* const rows) { 658 const int start_row = dec->last_row_; 659 const int end_row = start_row + num_rows; 660 const uint8_t* rows_in = rows; 661 uint8_t* rows_out = (uint8_t*)dec->io_->opaque + dec->io_->width * start_row; 662 VP8LTransform* const transform = &dec->transforms_[0]; 663 assert(dec->next_transform_ == 1); 664 assert(transform->type_ == COLOR_INDEXING_TRANSFORM); 665 VP8LColorIndexInverseTransformAlpha(transform, start_row, end_row, rows_in, 666 rows_out); 667} 668 669// Processes (transforms, scales & color-converts) the rows decoded after the 670// last call. 671static void ProcessRows(VP8LDecoder* const dec, int row) { 672 const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_; 673 const int num_rows = row - dec->last_row_; 674 675 if (num_rows <= 0) return; // Nothing to be done. 676 ApplyInverseTransforms(dec, num_rows, rows); 677 678 // Emit output. 679 { 680 VP8Io* const io = dec->io_; 681 uint8_t* rows_data = (uint8_t*)dec->argb_cache_; 682 const int in_stride = io->width * sizeof(uint32_t); // in unit of RGBA 683 if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) { 684 // Nothing to output (this time). 685 } else { 686 const WebPDecBuffer* const output = dec->output_; 687 if (output->colorspace < MODE_YUV) { // convert to RGBA 688 const WebPRGBABuffer* const buf = &output->u.RGBA; 689 uint8_t* const rgba = buf->rgba + dec->last_out_row_ * buf->stride; 690 const int num_rows_out = io->use_scaling ? 691 EmitRescaledRowsRGBA(dec, rows_data, in_stride, io->mb_h, 692 rgba, buf->stride) : 693 EmitRows(output->colorspace, rows_data, in_stride, 694 io->mb_w, io->mb_h, rgba, buf->stride); 695 // Update 'last_out_row_'. 696 dec->last_out_row_ += num_rows_out; 697 } else { // convert to YUVA 698 dec->last_out_row_ = io->use_scaling ? 699 EmitRescaledRowsYUVA(dec, rows_data, in_stride, io->mb_h) : 700 EmitRowsYUVA(dec, rows_data, in_stride, io->mb_w, io->mb_h); 701 } 702 assert(dec->last_out_row_ <= output->height); 703 } 704 } 705 706 // Update 'last_row_'. 707 dec->last_row_ = row; 708 assert(dec->last_row_ <= dec->height_); 709} 710 711// Row-processing for the special case when alpha data contains only one 712// transform (color indexing), and trivial non-green literals. 713static int Is8bOptimizable(const VP8LMetadata* const hdr) { 714 int i; 715 if (hdr->color_cache_size_ > 0) return 0; 716 // When the Huffman tree contains only one symbol, we can skip the 717 // call to ReadSymbol() for red/blue/alpha channels. 718 for (i = 0; i < hdr->num_htree_groups_; ++i) { 719 const HuffmanTree* const htrees = hdr->htree_groups_[i].htrees_; 720 if (htrees[RED].num_nodes_ > 1) return 0; 721 if (htrees[BLUE].num_nodes_ > 1) return 0; 722 if (htrees[ALPHA].num_nodes_ > 1) return 0; 723 } 724 return 1; 725} 726 727static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int row) { 728 const int num_rows = row - dec->last_row_; 729 const uint8_t* const in = 730 (uint8_t*)dec->pixels_ + dec->width_ * dec->last_row_; 731 if (num_rows > 0) { 732 ApplyInverseTransformsAlpha(dec, num_rows, in); 733 } 734 dec->last_row_ = dec->last_out_row_ = row; 735} 736 737static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data, 738 int width, int height, int last_row) { 739 int ok = 1; 740 int row = dec->last_pixel_ / width; 741 int col = dec->last_pixel_ % width; 742 VP8LBitReader* const br = &dec->br_; 743 VP8LMetadata* const hdr = &dec->hdr_; 744 const HTreeGroup* htree_group = GetHtreeGroupForPos(hdr, col, row); 745 int pos = dec->last_pixel_; // current position 746 const int end = width * height; // End of data 747 const int last = width * last_row; // Last pixel to decode 748 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES; 749 const int mask = hdr->huffman_mask_; 750 assert(htree_group != NULL); 751 assert(pos < end); 752 assert(last_row <= height); 753 assert(Is8bOptimizable(hdr)); 754 755 while (!br->eos_ && pos < last) { 756 int code; 757 // Only update when changing tile. 758 if ((col & mask) == 0) { 759 htree_group = GetHtreeGroupForPos(hdr, col, row); 760 } 761 VP8LFillBitWindow(br); 762 code = ReadSymbol(&htree_group->htrees_[GREEN], br); 763 if (code < NUM_LITERAL_CODES) { // Literal 764 data[pos] = code; 765 ++pos; 766 ++col; 767 if (col >= width) { 768 col = 0; 769 ++row; 770 if (row % NUM_ARGB_CACHE_ROWS == 0) { 771 ExtractPalettedAlphaRows(dec, row); 772 } 773 } 774 } else if (code < len_code_limit) { // Backward reference 775 int dist_code, dist; 776 const int length_sym = code - NUM_LITERAL_CODES; 777 const int length = GetCopyLength(length_sym, br); 778 const int dist_symbol = ReadSymbol(&htree_group->htrees_[DIST], br); 779 VP8LFillBitWindow(br); 780 dist_code = GetCopyDistance(dist_symbol, br); 781 dist = PlaneCodeToDistance(width, dist_code); 782 if (pos >= dist && end - pos >= length) { 783 int i; 784 for (i = 0; i < length; ++i) data[pos + i] = data[pos + i - dist]; 785 } else { 786 ok = 0; 787 goto End; 788 } 789 pos += length; 790 col += length; 791 while (col >= width) { 792 col -= width; 793 ++row; 794 if (row % NUM_ARGB_CACHE_ROWS == 0) { 795 ExtractPalettedAlphaRows(dec, row); 796 } 797 } 798 if (pos < last && (col & mask)) { 799 htree_group = GetHtreeGroupForPos(hdr, col, row); 800 } 801 } else { // Not reached 802 ok = 0; 803 goto End; 804 } 805 assert(br->eos_ == VP8LIsEndOfStream(br)); 806 ok = !br->error_; 807 if (!ok) goto End; 808 } 809 // Process the remaining rows corresponding to last row-block. 810 ExtractPalettedAlphaRows(dec, row); 811 812 End: 813 if (br->error_ || !ok || (br->eos_ && pos < end)) { 814 ok = 0; 815 dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED 816 : VP8_STATUS_BITSTREAM_ERROR; 817 } else { 818 dec->last_pixel_ = (int)pos; 819 if (pos == end) dec->state_ = READ_DATA; 820 } 821 return ok; 822} 823 824static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data, 825 int width, int height, int last_row, 826 ProcessRowsFunc process_func) { 827 int ok = 1; 828 int row = dec->last_pixel_ / width; 829 int col = dec->last_pixel_ % width; 830 VP8LBitReader* const br = &dec->br_; 831 VP8LMetadata* const hdr = &dec->hdr_; 832 HTreeGroup* htree_group = GetHtreeGroupForPos(hdr, col, row); 833 uint32_t* src = data + dec->last_pixel_; 834 uint32_t* last_cached = src; 835 uint32_t* const src_end = data + width * height; // End of data 836 uint32_t* const src_last = data + width * last_row; // Last pixel to decode 837 const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES; 838 const int color_cache_limit = len_code_limit + hdr->color_cache_size_; 839 VP8LColorCache* const color_cache = 840 (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL; 841 const int mask = hdr->huffman_mask_; 842 assert(htree_group != NULL); 843 assert(src < src_end); 844 assert(src_last <= src_end); 845 846 while (!br->eos_ && src < src_last) { 847 int code; 848 // Only update when changing tile. Note we could use this test: 849 // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed 850 // but that's actually slower and needs storing the previous col/row. 851 if ((col & mask) == 0) { 852 htree_group = GetHtreeGroupForPos(hdr, col, row); 853 } 854 VP8LFillBitWindow(br); 855 code = ReadSymbol(&htree_group->htrees_[GREEN], br); 856 if (code < NUM_LITERAL_CODES) { // Literal 857 int red, green, blue, alpha; 858 red = ReadSymbol(&htree_group->htrees_[RED], br); 859 green = code; 860 VP8LFillBitWindow(br); 861 blue = ReadSymbol(&htree_group->htrees_[BLUE], br); 862 alpha = ReadSymbol(&htree_group->htrees_[ALPHA], br); 863 *src = ((uint32_t)alpha << 24) | (red << 16) | (green << 8) | blue; 864 AdvanceByOne: 865 ++src; 866 ++col; 867 if (col >= width) { 868 col = 0; 869 ++row; 870 if ((row % NUM_ARGB_CACHE_ROWS == 0) && (process_func != NULL)) { 871 process_func(dec, row); 872 } 873 if (color_cache != NULL) { 874 while (last_cached < src) { 875 VP8LColorCacheInsert(color_cache, *last_cached++); 876 } 877 } 878 } 879 } else if (code < len_code_limit) { // Backward reference 880 int dist_code, dist; 881 const int length_sym = code - NUM_LITERAL_CODES; 882 const int length = GetCopyLength(length_sym, br); 883 const int dist_symbol = ReadSymbol(&htree_group->htrees_[DIST], br); 884 VP8LFillBitWindow(br); 885 dist_code = GetCopyDistance(dist_symbol, br); 886 dist = PlaneCodeToDistance(width, dist_code); 887 if (src - data < (ptrdiff_t)dist || src_end - src < (ptrdiff_t)length) { 888 ok = 0; 889 goto End; 890 } else { 891 int i; 892 for (i = 0; i < length; ++i) src[i] = src[i - dist]; 893 src += length; 894 } 895 col += length; 896 while (col >= width) { 897 col -= width; 898 ++row; 899 if ((row % NUM_ARGB_CACHE_ROWS == 0) && (process_func != NULL)) { 900 process_func(dec, row); 901 } 902 } 903 if (src < src_end) { 904 if (col & mask) htree_group = GetHtreeGroupForPos(hdr, col, row); 905 if (color_cache != NULL) { 906 while (last_cached < src) { 907 VP8LColorCacheInsert(color_cache, *last_cached++); 908 } 909 } 910 } 911 } else if (code < color_cache_limit) { // Color cache 912 const int key = code - len_code_limit; 913 assert(color_cache != NULL); 914 while (last_cached < src) { 915 VP8LColorCacheInsert(color_cache, *last_cached++); 916 } 917 *src = VP8LColorCacheLookup(color_cache, key); 918 goto AdvanceByOne; 919 } else { // Not reached 920 ok = 0; 921 goto End; 922 } 923 assert(br->eos_ == VP8LIsEndOfStream(br)); 924 ok = !br->error_; 925 if (!ok) goto End; 926 } 927 // Process the remaining rows corresponding to last row-block. 928 if (process_func != NULL) process_func(dec, row); 929 930 End: 931 if (br->error_ || !ok || (br->eos_ && src < src_end)) { 932 ok = 0; 933 dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED 934 : VP8_STATUS_BITSTREAM_ERROR; 935 } else { 936 dec->last_pixel_ = (int)(src - data); 937 if (src == src_end) dec->state_ = READ_DATA; 938 } 939 return ok; 940} 941 942// ----------------------------------------------------------------------------- 943// VP8LTransform 944 945static void ClearTransform(VP8LTransform* const transform) { 946 WebPSafeFree(transform->data_); 947 transform->data_ = NULL; 948} 949 950// For security reason, we need to remap the color map to span 951// the total possible bundled values, and not just the num_colors. 952static int ExpandColorMap(int num_colors, VP8LTransform* const transform) { 953 int i; 954 const int final_num_colors = 1 << (8 >> transform->bits_); 955 uint32_t* const new_color_map = 956 (uint32_t*)WebPSafeMalloc((uint64_t)final_num_colors, 957 sizeof(*new_color_map)); 958 if (new_color_map == NULL) { 959 return 0; 960 } else { 961 uint8_t* const data = (uint8_t*)transform->data_; 962 uint8_t* const new_data = (uint8_t*)new_color_map; 963 new_color_map[0] = transform->data_[0]; 964 for (i = 4; i < 4 * num_colors; ++i) { 965 // Equivalent to AddPixelEq(), on a byte-basis. 966 new_data[i] = (data[i] + new_data[i - 4]) & 0xff; 967 } 968 for (; i < 4 * final_num_colors; ++i) 969 new_data[i] = 0; // black tail. 970 WebPSafeFree(transform->data_); 971 transform->data_ = new_color_map; 972 } 973 return 1; 974} 975 976static int ReadTransform(int* const xsize, int const* ysize, 977 VP8LDecoder* const dec) { 978 int ok = 1; 979 VP8LBitReader* const br = &dec->br_; 980 VP8LTransform* transform = &dec->transforms_[dec->next_transform_]; 981 const VP8LImageTransformType type = 982 (VP8LImageTransformType)VP8LReadBits(br, 2); 983 984 // Each transform type can only be present once in the stream. 985 if (dec->transforms_seen_ & (1U << type)) { 986 return 0; // Already there, let's not accept the second same transform. 987 } 988 dec->transforms_seen_ |= (1U << type); 989 990 transform->type_ = type; 991 transform->xsize_ = *xsize; 992 transform->ysize_ = *ysize; 993 transform->data_ = NULL; 994 ++dec->next_transform_; 995 assert(dec->next_transform_ <= NUM_TRANSFORMS); 996 997 switch (type) { 998 case PREDICTOR_TRANSFORM: 999 case CROSS_COLOR_TRANSFORM: 1000 transform->bits_ = VP8LReadBits(br, 3) + 2; 1001 ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_, 1002 transform->bits_), 1003 VP8LSubSampleSize(transform->ysize_, 1004 transform->bits_), 1005 0, dec, &transform->data_); 1006 break; 1007 case COLOR_INDEXING_TRANSFORM: { 1008 const int num_colors = VP8LReadBits(br, 8) + 1; 1009 const int bits = (num_colors > 16) ? 0 1010 : (num_colors > 4) ? 1 1011 : (num_colors > 2) ? 2 1012 : 3; 1013 *xsize = VP8LSubSampleSize(transform->xsize_, bits); 1014 transform->bits_ = bits; 1015 ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_); 1016 ok = ok && ExpandColorMap(num_colors, transform); 1017 break; 1018 } 1019 case SUBTRACT_GREEN: 1020 break; 1021 default: 1022 assert(0); // can't happen 1023 break; 1024 } 1025 1026 return ok; 1027} 1028 1029// ----------------------------------------------------------------------------- 1030// VP8LMetadata 1031 1032static void InitMetadata(VP8LMetadata* const hdr) { 1033 assert(hdr); 1034 memset(hdr, 0, sizeof(*hdr)); 1035} 1036 1037static void ClearMetadata(VP8LMetadata* const hdr) { 1038 assert(hdr); 1039 1040 WebPSafeFree(hdr->huffman_image_); 1041 VP8LHtreeGroupsFree(hdr->htree_groups_, hdr->num_htree_groups_); 1042 VP8LColorCacheClear(&hdr->color_cache_); 1043 InitMetadata(hdr); 1044} 1045 1046// ----------------------------------------------------------------------------- 1047// VP8LDecoder 1048 1049VP8LDecoder* VP8LNew(void) { 1050 VP8LDecoder* const dec = (VP8LDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec)); 1051 if (dec == NULL) return NULL; 1052 dec->status_ = VP8_STATUS_OK; 1053 dec->action_ = READ_DIM; 1054 dec->state_ = READ_DIM; 1055 1056 VP8LDspInit(); // Init critical function pointers. 1057 1058 return dec; 1059} 1060 1061void VP8LClear(VP8LDecoder* const dec) { 1062 int i; 1063 if (dec == NULL) return; 1064 ClearMetadata(&dec->hdr_); 1065 1066 WebPSafeFree(dec->pixels_); 1067 dec->pixels_ = NULL; 1068 for (i = 0; i < dec->next_transform_; ++i) { 1069 ClearTransform(&dec->transforms_[i]); 1070 } 1071 dec->next_transform_ = 0; 1072 dec->transforms_seen_ = 0; 1073 1074 WebPSafeFree(dec->rescaler_memory); 1075 dec->rescaler_memory = NULL; 1076 1077 dec->output_ = NULL; // leave no trace behind 1078} 1079 1080void VP8LDelete(VP8LDecoder* const dec) { 1081 if (dec != NULL) { 1082 VP8LClear(dec); 1083 WebPSafeFree(dec); 1084 } 1085} 1086 1087static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) { 1088 VP8LMetadata* const hdr = &dec->hdr_; 1089 const int num_bits = hdr->huffman_subsample_bits_; 1090 dec->width_ = width; 1091 dec->height_ = height; 1092 1093 hdr->huffman_xsize_ = VP8LSubSampleSize(width, num_bits); 1094 hdr->huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1; 1095} 1096 1097static int DecodeImageStream(int xsize, int ysize, 1098 int is_level0, 1099 VP8LDecoder* const dec, 1100 uint32_t** const decoded_data) { 1101 int ok = 1; 1102 int transform_xsize = xsize; 1103 int transform_ysize = ysize; 1104 VP8LBitReader* const br = &dec->br_; 1105 VP8LMetadata* const hdr = &dec->hdr_; 1106 uint32_t* data = NULL; 1107 int color_cache_bits = 0; 1108 1109 // Read the transforms (may recurse). 1110 if (is_level0) { 1111 while (ok && VP8LReadBits(br, 1)) { 1112 ok = ReadTransform(&transform_xsize, &transform_ysize, dec); 1113 } 1114 } 1115 1116 // Color cache 1117 if (ok && VP8LReadBits(br, 1)) { 1118 color_cache_bits = VP8LReadBits(br, 4); 1119 ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS); 1120 if (!ok) { 1121 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1122 goto End; 1123 } 1124 } 1125 1126 // Read the Huffman codes (may recurse). 1127 ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize, 1128 color_cache_bits, is_level0); 1129 if (!ok) { 1130 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1131 goto End; 1132 } 1133 1134 // Finish setting up the color-cache 1135 if (color_cache_bits > 0) { 1136 hdr->color_cache_size_ = 1 << color_cache_bits; 1137 if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) { 1138 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1139 ok = 0; 1140 goto End; 1141 } 1142 } else { 1143 hdr->color_cache_size_ = 0; 1144 } 1145 UpdateDecoder(dec, transform_xsize, transform_ysize); 1146 1147 if (is_level0) { // level 0 complete 1148 dec->state_ = READ_HDR; 1149 goto End; 1150 } 1151 1152 { 1153 const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize; 1154 data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data)); 1155 if (data == NULL) { 1156 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1157 ok = 0; 1158 goto End; 1159 } 1160 } 1161 1162 // Use the Huffman trees to decode the LZ77 encoded data. 1163 ok = DecodeImageData(dec, data, transform_xsize, transform_ysize, 1164 transform_ysize, NULL); 1165 ok = ok && !br->error_; 1166 1167 End: 1168 1169 if (!ok) { 1170 WebPSafeFree(data); 1171 ClearMetadata(hdr); 1172 // If not enough data (br.eos_) resulted in BIT_STREAM_ERROR, update the 1173 // status appropriately. 1174 if (dec->status_ == VP8_STATUS_BITSTREAM_ERROR && dec->br_.eos_) { 1175 dec->status_ = VP8_STATUS_SUSPENDED; 1176 } 1177 } else { 1178 if (decoded_data != NULL) { 1179 *decoded_data = data; 1180 } else { 1181 // We allocate image data in this function only for transforms. At level 0 1182 // (that is: not the transforms), we shouldn't have allocated anything. 1183 assert(data == NULL); 1184 assert(is_level0); 1185 } 1186 dec->last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls. 1187 if (!is_level0) ClearMetadata(hdr); // Clean up temporary data behind. 1188 } 1189 return ok; 1190} 1191 1192//------------------------------------------------------------------------------ 1193// Allocate internal buffers dec->pixels_ and dec->argb_cache_. 1194static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) { 1195 const uint64_t num_pixels = (uint64_t)dec->width_ * dec->height_; 1196 // Scratch buffer corresponding to top-prediction row for transforming the 1197 // first row in the row-blocks. Not needed for paletted alpha. 1198 const uint64_t cache_top_pixels = (uint16_t)final_width; 1199 // Scratch buffer for temporary BGRA storage. Not needed for paletted alpha. 1200 const uint64_t cache_pixels = (uint64_t)final_width * NUM_ARGB_CACHE_ROWS; 1201 const uint64_t total_num_pixels = 1202 num_pixels + cache_top_pixels + cache_pixels; 1203 1204 assert(dec->width_ <= final_width); 1205 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t)); 1206 if (dec->pixels_ == NULL) { 1207 dec->argb_cache_ = NULL; // for sanity check 1208 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1209 return 0; 1210 } 1211 dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels; 1212 return 1; 1213} 1214 1215static int AllocateInternalBuffers8b(VP8LDecoder* const dec) { 1216 const uint64_t total_num_pixels = (uint64_t)dec->width_ * dec->height_; 1217 dec->argb_cache_ = NULL; // for sanity check 1218 dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t)); 1219 if (dec->pixels_ == NULL) { 1220 dec->status_ = VP8_STATUS_OUT_OF_MEMORY; 1221 return 0; 1222 } 1223 return 1; 1224} 1225 1226//------------------------------------------------------------------------------ 1227 1228// Special row-processing that only stores the alpha data. 1229static void ExtractAlphaRows(VP8LDecoder* const dec, int row) { 1230 const int num_rows = row - dec->last_row_; 1231 const uint32_t* const in = dec->pixels_ + dec->width_ * dec->last_row_; 1232 1233 if (num_rows <= 0) return; // Nothing to be done. 1234 ApplyInverseTransforms(dec, num_rows, in); 1235 1236 // Extract alpha (which is stored in the green plane). 1237 { 1238 const int width = dec->io_->width; // the final width (!= dec->width_) 1239 const int cache_pixs = width * num_rows; 1240 uint8_t* const dst = (uint8_t*)dec->io_->opaque + width * dec->last_row_; 1241 const uint32_t* const src = dec->argb_cache_; 1242 int i; 1243 for (i = 0; i < cache_pixs; ++i) dst[i] = (src[i] >> 8) & 0xff; 1244 } 1245 dec->last_row_ = dec->last_out_row_ = row; 1246} 1247 1248int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec, 1249 const uint8_t* const data, size_t data_size, 1250 uint8_t* const output) { 1251 int ok = 0; 1252 VP8LDecoder* dec; 1253 VP8Io* io; 1254 assert(alph_dec != NULL); 1255 alph_dec->vp8l_dec_ = VP8LNew(); 1256 if (alph_dec->vp8l_dec_ == NULL) return 0; 1257 dec = alph_dec->vp8l_dec_; 1258 1259 dec->width_ = alph_dec->width_; 1260 dec->height_ = alph_dec->height_; 1261 dec->io_ = &alph_dec->io_; 1262 io = dec->io_; 1263 1264 VP8InitIo(io); 1265 WebPInitCustomIo(NULL, io); // Just a sanity Init. io won't be used. 1266 io->opaque = output; 1267 io->width = alph_dec->width_; 1268 io->height = alph_dec->height_; 1269 1270 dec->status_ = VP8_STATUS_OK; 1271 VP8LInitBitReader(&dec->br_, data, data_size); 1272 1273 dec->action_ = READ_HDR; 1274 if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) { 1275 goto Err; 1276 } 1277 1278 // Special case: if alpha data uses only the color indexing transform and 1279 // doesn't use color cache (a frequent case), we will use DecodeAlphaData() 1280 // method that only needs allocation of 1 byte per pixel (alpha channel). 1281 if (dec->next_transform_ == 1 && 1282 dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM && 1283 Is8bOptimizable(&dec->hdr_)) { 1284 alph_dec->use_8b_decode = 1; 1285 ok = AllocateInternalBuffers8b(dec); 1286 } else { 1287 // Allocate internal buffers (note that dec->width_ may have changed here). 1288 alph_dec->use_8b_decode = 0; 1289 ok = AllocateInternalBuffers32b(dec, alph_dec->width_); 1290 } 1291 1292 if (!ok) goto Err; 1293 1294 dec->action_ = READ_DATA; 1295 return 1; 1296 1297 Err: 1298 VP8LDelete(alph_dec->vp8l_dec_); 1299 alph_dec->vp8l_dec_ = NULL; 1300 return 0; 1301} 1302 1303int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) { 1304 VP8LDecoder* const dec = alph_dec->vp8l_dec_; 1305 assert(dec != NULL); 1306 assert(dec->action_ == READ_DATA); 1307 assert(last_row <= dec->height_); 1308 1309 if (dec->last_pixel_ == dec->width_ * dec->height_) { 1310 return 1; // done 1311 } 1312 1313 // Decode (with special row processing). 1314 return alph_dec->use_8b_decode ? 1315 DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_, 1316 last_row) : 1317 DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_, 1318 last_row, ExtractAlphaRows); 1319} 1320 1321//------------------------------------------------------------------------------ 1322 1323int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) { 1324 int width, height, has_alpha; 1325 1326 if (dec == NULL) return 0; 1327 if (io == NULL) { 1328 dec->status_ = VP8_STATUS_INVALID_PARAM; 1329 return 0; 1330 } 1331 1332 dec->io_ = io; 1333 dec->status_ = VP8_STATUS_OK; 1334 VP8LInitBitReader(&dec->br_, io->data, io->data_size); 1335 if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) { 1336 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1337 goto Error; 1338 } 1339 dec->state_ = READ_DIM; 1340 io->width = width; 1341 io->height = height; 1342 1343 dec->action_ = READ_HDR; 1344 if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error; 1345 return 1; 1346 1347 Error: 1348 VP8LClear(dec); 1349 assert(dec->status_ != VP8_STATUS_OK); 1350 return 0; 1351} 1352 1353int VP8LDecodeImage(VP8LDecoder* const dec) { 1354 VP8Io* io = NULL; 1355 WebPDecParams* params = NULL; 1356 1357 // Sanity checks. 1358 if (dec == NULL) return 0; 1359 1360 dec->status_ = VP8_STATUS_BITSTREAM_ERROR; 1361 assert(dec->hdr_.htree_groups_ != NULL); 1362 assert(dec->hdr_.num_htree_groups_ > 0); 1363 1364 io = dec->io_; 1365 assert(io != NULL); 1366 params = (WebPDecParams*)io->opaque; 1367 assert(params != NULL); 1368 dec->output_ = params->output; 1369 assert(dec->output_ != NULL); 1370 1371 // Initialization. 1372 if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) { 1373 dec->status_ = VP8_STATUS_INVALID_PARAM; 1374 goto Err; 1375 } 1376 1377 if (!AllocateInternalBuffers32b(dec, io->width)) goto Err; 1378 1379 if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err; 1380 1381 if (io->use_scaling || WebPIsPremultipliedMode(dec->output_->colorspace)) { 1382 // need the alpha-multiply functions for premultiplied output or rescaling 1383 WebPInitAlphaProcessing(); 1384 } 1385 1386 // Decode. 1387 dec->action_ = READ_DATA; 1388 if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_, 1389 dec->height_, ProcessRows)) { 1390 goto Err; 1391 } 1392 1393 // Cleanup. 1394 params->last_y = dec->last_out_row_; 1395 VP8LClear(dec); 1396 return 1; 1397 1398 Err: 1399 VP8LClear(dec); 1400 assert(dec->status_ != VP8_STATUS_OK); 1401 return 0; 1402} 1403 1404//------------------------------------------------------------------------------ 1405