1 // Copyright 2011 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 // Incremental decoding 11 // 12 // Author: somnath (at) google.com (Somnath Banerjee) 13 14 #include <assert.h> 15 #include <string.h> 16 #include <stdlib.h> 17 18 #include "./alphai.h" 19 #include "./webpi.h" 20 #include "./vp8i.h" 21 #include "../utils/utils.h" 22 23 // In append mode, buffer allocations increase as multiples of this value. 24 // Needs to be a power of 2. 25 #define CHUNK_SIZE 4096 26 #define MAX_MB_SIZE 4096 27 28 //------------------------------------------------------------------------------ 29 // Data structures for memory and states 30 31 // Decoding states. State normally flows as: 32 // WEBP_HEADER->VP8_HEADER->VP8_PARTS0->VP8_DATA->DONE for a lossy image, and 33 // WEBP_HEADER->VP8L_HEADER->VP8L_DATA->DONE for a lossless image. 34 // If there is any error the decoder goes into state ERROR. 35 typedef enum { 36 STATE_WEBP_HEADER, // All the data before that of the VP8/VP8L chunk. 37 STATE_VP8_HEADER, // The VP8 Frame header (within the VP8 chunk). 38 STATE_VP8_PARTS0, 39 STATE_VP8_DATA, 40 STATE_VP8L_HEADER, 41 STATE_VP8L_DATA, 42 STATE_DONE, 43 STATE_ERROR 44 } DecState; 45 46 // Operating state for the MemBuffer 47 typedef enum { 48 MEM_MODE_NONE = 0, 49 MEM_MODE_APPEND, 50 MEM_MODE_MAP 51 } MemBufferMode; 52 53 // storage for partition #0 and partial data (in a rolling fashion) 54 typedef struct { 55 MemBufferMode mode_; // Operation mode 56 size_t start_; // start location of the data to be decoded 57 size_t end_; // end location 58 size_t buf_size_; // size of the allocated buffer 59 uint8_t* buf_; // We don't own this buffer in case WebPIUpdate() 60 61 size_t part0_size_; // size of partition #0 62 const uint8_t* part0_buf_; // buffer to store partition #0 63 } MemBuffer; 64 65 struct WebPIDecoder { 66 DecState state_; // current decoding state 67 WebPDecParams params_; // Params to store output info 68 int is_lossless_; // for down-casting 'dec_'. 69 void* dec_; // either a VP8Decoder or a VP8LDecoder instance 70 VP8Io io_; 71 72 MemBuffer mem_; // input memory buffer. 73 WebPDecBuffer output_; // output buffer (when no external one is supplied) 74 size_t chunk_size_; // Compressed VP8/VP8L size extracted from Header. 75 76 int last_mb_y_; // last row reached for intra-mode decoding 77 }; 78 79 // MB context to restore in case VP8DecodeMB() fails 80 typedef struct { 81 VP8MB left_; 82 VP8MB info_; 83 VP8BitReader token_br_; 84 } MBContext; 85 86 //------------------------------------------------------------------------------ 87 // MemBuffer: incoming data handling 88 89 static WEBP_INLINE size_t MemDataSize(const MemBuffer* mem) { 90 return (mem->end_ - mem->start_); 91 } 92 93 // Check if we need to preserve the compressed alpha data, as it may not have 94 // been decoded yet. 95 static int NeedCompressedAlpha(const WebPIDecoder* const idec) { 96 if (idec->state_ == STATE_WEBP_HEADER) { 97 // We haven't parsed the headers yet, so we don't know whether the image is 98 // lossy or lossless. This also means that we haven't parsed the ALPH chunk. 99 return 0; 100 } 101 if (idec->is_lossless_) { 102 return 0; // ALPH chunk is not present for lossless images. 103 } else { 104 const VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 105 assert(dec != NULL); // Must be true as idec->state_ != STATE_WEBP_HEADER. 106 return (dec->alpha_data_ != NULL) && !dec->is_alpha_decoded_; 107 } 108 } 109 110 static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) { 111 MemBuffer* const mem = &idec->mem_; 112 const uint8_t* const new_base = mem->buf_ + mem->start_; 113 // note: for VP8, setting up idec->io_ is only really needed at the beginning 114 // of the decoding, till partition #0 is complete. 115 idec->io_.data = new_base; 116 idec->io_.data_size = MemDataSize(mem); 117 118 if (idec->dec_ != NULL) { 119 if (!idec->is_lossless_) { 120 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 121 const int last_part = dec->num_parts_ - 1; 122 if (offset != 0) { 123 int p; 124 for (p = 0; p <= last_part; ++p) { 125 VP8RemapBitReader(dec->parts_ + p, offset); 126 } 127 // Remap partition #0 data pointer to new offset, but only in MAP 128 // mode (in APPEND mode, partition #0 is copied into a fixed memory). 129 if (mem->mode_ == MEM_MODE_MAP) { 130 VP8RemapBitReader(&dec->br_, offset); 131 } 132 } 133 assert(last_part >= 0); 134 dec->parts_[last_part].buf_end_ = mem->buf_ + mem->end_; 135 if (NeedCompressedAlpha(idec)) { 136 ALPHDecoder* const alph_dec = dec->alph_dec_; 137 dec->alpha_data_ += offset; 138 if (alph_dec != NULL) { 139 if (alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION) { 140 VP8LDecoder* const alph_vp8l_dec = alph_dec->vp8l_dec_; 141 assert(alph_vp8l_dec != NULL); 142 assert(dec->alpha_data_size_ >= ALPHA_HEADER_LEN); 143 VP8LBitReaderSetBuffer(&alph_vp8l_dec->br_, 144 dec->alpha_data_ + ALPHA_HEADER_LEN, 145 dec->alpha_data_size_ - ALPHA_HEADER_LEN); 146 } else { // alph_dec->method_ == ALPHA_NO_COMPRESSION 147 // Nothing special to do in this case. 148 } 149 } 150 } 151 } else { // Resize lossless bitreader 152 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 153 VP8LBitReaderSetBuffer(&dec->br_, new_base, MemDataSize(mem)); 154 } 155 } 156 } 157 158 // Appends data to the end of MemBuffer->buf_. It expands the allocated memory 159 // size if required and also updates VP8BitReader's if new memory is allocated. 160 static int AppendToMemBuffer(WebPIDecoder* const idec, 161 const uint8_t* const data, size_t data_size) { 162 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 163 MemBuffer* const mem = &idec->mem_; 164 const int need_compressed_alpha = NeedCompressedAlpha(idec); 165 const uint8_t* const old_start = mem->buf_ + mem->start_; 166 const uint8_t* const old_base = 167 need_compressed_alpha ? dec->alpha_data_ : old_start; 168 assert(mem->mode_ == MEM_MODE_APPEND); 169 if (data_size > MAX_CHUNK_PAYLOAD) { 170 // security safeguard: trying to allocate more than what the format 171 // allows for a chunk should be considered a smoke smell. 172 return 0; 173 } 174 175 if (mem->end_ + data_size > mem->buf_size_) { // Need some free memory 176 const size_t new_mem_start = old_start - old_base; 177 const size_t current_size = MemDataSize(mem) + new_mem_start; 178 const uint64_t new_size = (uint64_t)current_size + data_size; 179 const uint64_t extra_size = (new_size + CHUNK_SIZE - 1) & ~(CHUNK_SIZE - 1); 180 uint8_t* const new_buf = 181 (uint8_t*)WebPSafeMalloc(extra_size, sizeof(*new_buf)); 182 if (new_buf == NULL) return 0; 183 memcpy(new_buf, old_base, current_size); 184 WebPSafeFree(mem->buf_); 185 mem->buf_ = new_buf; 186 mem->buf_size_ = (size_t)extra_size; 187 mem->start_ = new_mem_start; 188 mem->end_ = current_size; 189 } 190 191 memcpy(mem->buf_ + mem->end_, data, data_size); 192 mem->end_ += data_size; 193 assert(mem->end_ <= mem->buf_size_); 194 195 DoRemap(idec, mem->buf_ + mem->start_ - old_start); 196 return 1; 197 } 198 199 static int RemapMemBuffer(WebPIDecoder* const idec, 200 const uint8_t* const data, size_t data_size) { 201 MemBuffer* const mem = &idec->mem_; 202 const uint8_t* const old_buf = mem->buf_; 203 const uint8_t* const old_start = old_buf + mem->start_; 204 assert(mem->mode_ == MEM_MODE_MAP); 205 206 if (data_size < mem->buf_size_) return 0; // can't remap to a shorter buffer! 207 208 mem->buf_ = (uint8_t*)data; 209 mem->end_ = mem->buf_size_ = data_size; 210 211 DoRemap(idec, mem->buf_ + mem->start_ - old_start); 212 return 1; 213 } 214 215 static void InitMemBuffer(MemBuffer* const mem) { 216 mem->mode_ = MEM_MODE_NONE; 217 mem->buf_ = NULL; 218 mem->buf_size_ = 0; 219 mem->part0_buf_ = NULL; 220 mem->part0_size_ = 0; 221 } 222 223 static void ClearMemBuffer(MemBuffer* const mem) { 224 assert(mem); 225 if (mem->mode_ == MEM_MODE_APPEND) { 226 WebPSafeFree(mem->buf_); 227 WebPSafeFree((void*)mem->part0_buf_); 228 } 229 } 230 231 static int CheckMemBufferMode(MemBuffer* const mem, MemBufferMode expected) { 232 if (mem->mode_ == MEM_MODE_NONE) { 233 mem->mode_ = expected; // switch to the expected mode 234 } else if (mem->mode_ != expected) { 235 return 0; // we mixed the modes => error 236 } 237 assert(mem->mode_ == expected); // mode is ok 238 return 1; 239 } 240 241 // To be called last. 242 static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) { 243 #if WEBP_DECODER_ABI_VERSION > 0x0203 244 const WebPDecoderOptions* const options = idec->params_.options; 245 WebPDecBuffer* const output = idec->params_.output; 246 247 idec->state_ = STATE_DONE; 248 if (options != NULL && options->flip) { 249 return WebPFlipBuffer(output); 250 } 251 #endif 252 idec->state_ = STATE_DONE; 253 return VP8_STATUS_OK; 254 } 255 256 //------------------------------------------------------------------------------ 257 // Macroblock-decoding contexts 258 259 static void SaveContext(const VP8Decoder* dec, const VP8BitReader* token_br, 260 MBContext* const context) { 261 context->left_ = dec->mb_info_[-1]; 262 context->info_ = dec->mb_info_[dec->mb_x_]; 263 context->token_br_ = *token_br; 264 } 265 266 static void RestoreContext(const MBContext* context, VP8Decoder* const dec, 267 VP8BitReader* const token_br) { 268 dec->mb_info_[-1] = context->left_; 269 dec->mb_info_[dec->mb_x_] = context->info_; 270 *token_br = context->token_br_; 271 } 272 273 //------------------------------------------------------------------------------ 274 275 static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) { 276 if (idec->state_ == STATE_VP8_DATA) { 277 VP8Io* const io = &idec->io_; 278 if (io->teardown != NULL) { 279 io->teardown(io); 280 } 281 } 282 idec->state_ = STATE_ERROR; 283 return error; 284 } 285 286 static void ChangeState(WebPIDecoder* const idec, DecState new_state, 287 size_t consumed_bytes) { 288 MemBuffer* const mem = &idec->mem_; 289 idec->state_ = new_state; 290 mem->start_ += consumed_bytes; 291 assert(mem->start_ <= mem->end_); 292 idec->io_.data = mem->buf_ + mem->start_; 293 idec->io_.data_size = MemDataSize(mem); 294 } 295 296 // Headers 297 static VP8StatusCode DecodeWebPHeaders(WebPIDecoder* const idec) { 298 MemBuffer* const mem = &idec->mem_; 299 const uint8_t* data = mem->buf_ + mem->start_; 300 size_t curr_size = MemDataSize(mem); 301 VP8StatusCode status; 302 WebPHeaderStructure headers; 303 304 headers.data = data; 305 headers.data_size = curr_size; 306 headers.have_all_data = 0; 307 status = WebPParseHeaders(&headers); 308 if (status == VP8_STATUS_NOT_ENOUGH_DATA) { 309 return VP8_STATUS_SUSPENDED; // We haven't found a VP8 chunk yet. 310 } else if (status != VP8_STATUS_OK) { 311 return IDecError(idec, status); 312 } 313 314 idec->chunk_size_ = headers.compressed_size; 315 idec->is_lossless_ = headers.is_lossless; 316 if (!idec->is_lossless_) { 317 VP8Decoder* const dec = VP8New(); 318 if (dec == NULL) { 319 return VP8_STATUS_OUT_OF_MEMORY; 320 } 321 idec->dec_ = dec; 322 dec->alpha_data_ = headers.alpha_data; 323 dec->alpha_data_size_ = headers.alpha_data_size; 324 ChangeState(idec, STATE_VP8_HEADER, headers.offset); 325 } else { 326 VP8LDecoder* const dec = VP8LNew(); 327 if (dec == NULL) { 328 return VP8_STATUS_OUT_OF_MEMORY; 329 } 330 idec->dec_ = dec; 331 ChangeState(idec, STATE_VP8L_HEADER, headers.offset); 332 } 333 return VP8_STATUS_OK; 334 } 335 336 static VP8StatusCode DecodeVP8FrameHeader(WebPIDecoder* const idec) { 337 const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_; 338 const size_t curr_size = MemDataSize(&idec->mem_); 339 int width, height; 340 uint32_t bits; 341 342 if (curr_size < VP8_FRAME_HEADER_SIZE) { 343 // Not enough data bytes to extract VP8 Frame Header. 344 return VP8_STATUS_SUSPENDED; 345 } 346 if (!VP8GetInfo(data, curr_size, idec->chunk_size_, &width, &height)) { 347 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 348 } 349 350 bits = data[0] | (data[1] << 8) | (data[2] << 16); 351 idec->mem_.part0_size_ = (bits >> 5) + VP8_FRAME_HEADER_SIZE; 352 353 idec->io_.data = data; 354 idec->io_.data_size = curr_size; 355 idec->state_ = STATE_VP8_PARTS0; 356 return VP8_STATUS_OK; 357 } 358 359 // Partition #0 360 static int CopyParts0Data(WebPIDecoder* const idec) { 361 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 362 VP8BitReader* const br = &dec->br_; 363 const size_t psize = br->buf_end_ - br->buf_; 364 MemBuffer* const mem = &idec->mem_; 365 assert(!idec->is_lossless_); 366 assert(mem->part0_buf_ == NULL); 367 assert(psize > 0); 368 assert(psize <= mem->part0_size_); // Format limit: no need for runtime check 369 if (mem->mode_ == MEM_MODE_APPEND) { 370 // We copy and grab ownership of the partition #0 data. 371 uint8_t* const part0_buf = (uint8_t*)WebPSafeMalloc(1ULL, psize); 372 if (part0_buf == NULL) { 373 return 0; 374 } 375 memcpy(part0_buf, br->buf_, psize); 376 mem->part0_buf_ = part0_buf; 377 br->buf_ = part0_buf; 378 br->buf_end_ = part0_buf + psize; 379 } else { 380 // Else: just keep pointers to the partition #0's data in dec_->br_. 381 } 382 mem->start_ += psize; 383 return 1; 384 } 385 386 static VP8StatusCode DecodePartition0(WebPIDecoder* const idec) { 387 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 388 VP8Io* const io = &idec->io_; 389 const WebPDecParams* const params = &idec->params_; 390 WebPDecBuffer* const output = params->output; 391 392 // Wait till we have enough data for the whole partition #0 393 if (MemDataSize(&idec->mem_) < idec->mem_.part0_size_) { 394 return VP8_STATUS_SUSPENDED; 395 } 396 397 if (!VP8GetHeaders(dec, io)) { 398 const VP8StatusCode status = dec->status_; 399 if (status == VP8_STATUS_SUSPENDED || 400 status == VP8_STATUS_NOT_ENOUGH_DATA) { 401 // treating NOT_ENOUGH_DATA as SUSPENDED state 402 return VP8_STATUS_SUSPENDED; 403 } 404 return IDecError(idec, status); 405 } 406 407 // Allocate/Verify output buffer now 408 dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options, 409 output); 410 if (dec->status_ != VP8_STATUS_OK) { 411 return IDecError(idec, dec->status_); 412 } 413 // This change must be done before calling VP8InitFrame() 414 dec->mt_method_ = VP8GetThreadMethod(params->options, NULL, 415 io->width, io->height); 416 VP8InitDithering(params->options, dec); 417 if (!CopyParts0Data(idec)) { 418 return IDecError(idec, VP8_STATUS_OUT_OF_MEMORY); 419 } 420 421 // Finish setting up the decoding parameters. Will call io->setup(). 422 if (VP8EnterCritical(dec, io) != VP8_STATUS_OK) { 423 return IDecError(idec, dec->status_); 424 } 425 426 // Note: past this point, teardown() must always be called 427 // in case of error. 428 idec->state_ = STATE_VP8_DATA; 429 // Allocate memory and prepare everything. 430 if (!VP8InitFrame(dec, io)) { 431 return IDecError(idec, dec->status_); 432 } 433 return VP8_STATUS_OK; 434 } 435 436 // Remaining partitions 437 static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) { 438 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 439 VP8Io* const io = &idec->io_; 440 441 assert(dec->ready_); 442 for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) { 443 if (idec->last_mb_y_ != dec->mb_y_) { 444 if (!VP8ParseIntraModeRow(&dec->br_, dec)) { 445 // note: normally, error shouldn't occur since we already have the whole 446 // partition0 available here in DecodeRemaining(). Reaching EOF while 447 // reading intra modes really means a BITSTREAM_ERROR. 448 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 449 } 450 idec->last_mb_y_ = dec->mb_y_; 451 } 452 for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) { 453 VP8BitReader* const token_br = 454 &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)]; 455 MBContext context; 456 SaveContext(dec, token_br, &context); 457 if (!VP8DecodeMB(dec, token_br)) { 458 // We shouldn't fail when MAX_MB data was available 459 if (dec->num_parts_ == 1 && MemDataSize(&idec->mem_) > MAX_MB_SIZE) { 460 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 461 } 462 RestoreContext(&context, dec, token_br); 463 return VP8_STATUS_SUSPENDED; 464 } 465 // Release buffer only if there is only one partition 466 if (dec->num_parts_ == 1) { 467 idec->mem_.start_ = token_br->buf_ - idec->mem_.buf_; 468 assert(idec->mem_.start_ <= idec->mem_.end_); 469 } 470 } 471 VP8InitScanline(dec); // Prepare for next scanline 472 473 // Reconstruct, filter and emit the row. 474 if (!VP8ProcessRow(dec, io)) { 475 return IDecError(idec, VP8_STATUS_USER_ABORT); 476 } 477 } 478 // Synchronize the thread and check for errors. 479 if (!VP8ExitCritical(dec, io)) { 480 return IDecError(idec, VP8_STATUS_USER_ABORT); 481 } 482 dec->ready_ = 0; 483 return FinishDecoding(idec); 484 } 485 486 static VP8StatusCode ErrorStatusLossless(WebPIDecoder* const idec, 487 VP8StatusCode status) { 488 if (status == VP8_STATUS_SUSPENDED || status == VP8_STATUS_NOT_ENOUGH_DATA) { 489 return VP8_STATUS_SUSPENDED; 490 } 491 return IDecError(idec, status); 492 } 493 494 static VP8StatusCode DecodeVP8LHeader(WebPIDecoder* const idec) { 495 VP8Io* const io = &idec->io_; 496 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 497 const WebPDecParams* const params = &idec->params_; 498 WebPDecBuffer* const output = params->output; 499 size_t curr_size = MemDataSize(&idec->mem_); 500 assert(idec->is_lossless_); 501 502 // Wait until there's enough data for decoding header. 503 if (curr_size < (idec->chunk_size_ >> 3)) { 504 return VP8_STATUS_SUSPENDED; 505 } 506 if (!VP8LDecodeHeader(dec, io)) { 507 return ErrorStatusLossless(idec, dec->status_); 508 } 509 // Allocate/verify output buffer now. 510 dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options, 511 output); 512 if (dec->status_ != VP8_STATUS_OK) { 513 return IDecError(idec, dec->status_); 514 } 515 516 idec->state_ = STATE_VP8L_DATA; 517 return VP8_STATUS_OK; 518 } 519 520 static VP8StatusCode DecodeVP8LData(WebPIDecoder* const idec) { 521 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 522 const size_t curr_size = MemDataSize(&idec->mem_); 523 assert(idec->is_lossless_); 524 525 // At present Lossless decoder can't decode image incrementally. So wait till 526 // all the image data is aggregated before image can be decoded. 527 if (curr_size < idec->chunk_size_) { 528 return VP8_STATUS_SUSPENDED; 529 } 530 531 if (!VP8LDecodeImage(dec)) { 532 return ErrorStatusLossless(idec, dec->status_); 533 } 534 535 return FinishDecoding(idec); 536 } 537 538 // Main decoding loop 539 static VP8StatusCode IDecode(WebPIDecoder* idec) { 540 VP8StatusCode status = VP8_STATUS_SUSPENDED; 541 542 if (idec->state_ == STATE_WEBP_HEADER) { 543 status = DecodeWebPHeaders(idec); 544 } else { 545 if (idec->dec_ == NULL) { 546 return VP8_STATUS_SUSPENDED; // can't continue if we have no decoder. 547 } 548 } 549 if (idec->state_ == STATE_VP8_HEADER) { 550 status = DecodeVP8FrameHeader(idec); 551 } 552 if (idec->state_ == STATE_VP8_PARTS0) { 553 status = DecodePartition0(idec); 554 } 555 if (idec->state_ == STATE_VP8_DATA) { 556 status = DecodeRemaining(idec); 557 } 558 if (idec->state_ == STATE_VP8L_HEADER) { 559 status = DecodeVP8LHeader(idec); 560 } 561 if (idec->state_ == STATE_VP8L_DATA) { 562 status = DecodeVP8LData(idec); 563 } 564 return status; 565 } 566 567 //------------------------------------------------------------------------------ 568 // Public functions 569 570 WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) { 571 WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL, sizeof(*idec)); 572 if (idec == NULL) { 573 return NULL; 574 } 575 576 idec->state_ = STATE_WEBP_HEADER; 577 idec->chunk_size_ = 0; 578 579 idec->last_mb_y_ = -1; 580 581 InitMemBuffer(&idec->mem_); 582 WebPInitDecBuffer(&idec->output_); 583 VP8InitIo(&idec->io_); 584 585 WebPResetDecParams(&idec->params_); 586 idec->params_.output = (output_buffer != NULL) ? output_buffer 587 : &idec->output_; 588 WebPInitCustomIo(&idec->params_, &idec->io_); // Plug the I/O functions. 589 590 return idec; 591 } 592 593 WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size, 594 WebPDecoderConfig* config) { 595 WebPIDecoder* idec; 596 597 // Parse the bitstream's features, if requested: 598 if (data != NULL && data_size > 0 && config != NULL) { 599 if (WebPGetFeatures(data, data_size, &config->input) != VP8_STATUS_OK) { 600 return NULL; 601 } 602 } 603 // Create an instance of the incremental decoder 604 idec = WebPINewDecoder(config ? &config->output : NULL); 605 if (idec == NULL) { 606 return NULL; 607 } 608 // Finish initialization 609 if (config != NULL) { 610 idec->params_.options = &config->options; 611 } 612 return idec; 613 } 614 615 void WebPIDelete(WebPIDecoder* idec) { 616 if (idec == NULL) return; 617 if (idec->dec_ != NULL) { 618 if (!idec->is_lossless_) { 619 if (idec->state_ == STATE_VP8_DATA) { 620 // Synchronize the thread, clean-up and check for errors. 621 VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_); 622 } 623 VP8Delete((VP8Decoder*)idec->dec_); 624 } else { 625 VP8LDelete((VP8LDecoder*)idec->dec_); 626 } 627 } 628 ClearMemBuffer(&idec->mem_); 629 WebPFreeDecBuffer(&idec->output_); 630 WebPSafeFree(idec); 631 } 632 633 //------------------------------------------------------------------------------ 634 // Wrapper toward WebPINewDecoder 635 636 WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE mode, uint8_t* output_buffer, 637 size_t output_buffer_size, int output_stride) { 638 const int is_external_memory = (output_buffer != NULL); 639 WebPIDecoder* idec; 640 641 if (mode >= MODE_YUV) return NULL; 642 if (!is_external_memory) { // Overwrite parameters to sane values. 643 output_buffer_size = 0; 644 output_stride = 0; 645 } else { // A buffer was passed. Validate the other params. 646 if (output_stride == 0 || output_buffer_size == 0) { 647 return NULL; // invalid parameter. 648 } 649 } 650 idec = WebPINewDecoder(NULL); 651 if (idec == NULL) return NULL; 652 idec->output_.colorspace = mode; 653 idec->output_.is_external_memory = is_external_memory; 654 idec->output_.u.RGBA.rgba = output_buffer; 655 idec->output_.u.RGBA.stride = output_stride; 656 idec->output_.u.RGBA.size = output_buffer_size; 657 return idec; 658 } 659 660 WebPIDecoder* WebPINewYUVA(uint8_t* luma, size_t luma_size, int luma_stride, 661 uint8_t* u, size_t u_size, int u_stride, 662 uint8_t* v, size_t v_size, int v_stride, 663 uint8_t* a, size_t a_size, int a_stride) { 664 const int is_external_memory = (luma != NULL); 665 WebPIDecoder* idec; 666 WEBP_CSP_MODE colorspace; 667 668 if (!is_external_memory) { // Overwrite parameters to sane values. 669 luma_size = u_size = v_size = a_size = 0; 670 luma_stride = u_stride = v_stride = a_stride = 0; 671 u = v = a = NULL; 672 colorspace = MODE_YUVA; 673 } else { // A luma buffer was passed. Validate the other parameters. 674 if (u == NULL || v == NULL) return NULL; 675 if (luma_size == 0 || u_size == 0 || v_size == 0) return NULL; 676 if (luma_stride == 0 || u_stride == 0 || v_stride == 0) return NULL; 677 if (a != NULL) { 678 if (a_size == 0 || a_stride == 0) return NULL; 679 } 680 colorspace = (a == NULL) ? MODE_YUV : MODE_YUVA; 681 } 682 683 idec = WebPINewDecoder(NULL); 684 if (idec == NULL) return NULL; 685 686 idec->output_.colorspace = colorspace; 687 idec->output_.is_external_memory = is_external_memory; 688 idec->output_.u.YUVA.y = luma; 689 idec->output_.u.YUVA.y_stride = luma_stride; 690 idec->output_.u.YUVA.y_size = luma_size; 691 idec->output_.u.YUVA.u = u; 692 idec->output_.u.YUVA.u_stride = u_stride; 693 idec->output_.u.YUVA.u_size = u_size; 694 idec->output_.u.YUVA.v = v; 695 idec->output_.u.YUVA.v_stride = v_stride; 696 idec->output_.u.YUVA.v_size = v_size; 697 idec->output_.u.YUVA.a = a; 698 idec->output_.u.YUVA.a_stride = a_stride; 699 idec->output_.u.YUVA.a_size = a_size; 700 return idec; 701 } 702 703 WebPIDecoder* WebPINewYUV(uint8_t* luma, size_t luma_size, int luma_stride, 704 uint8_t* u, size_t u_size, int u_stride, 705 uint8_t* v, size_t v_size, int v_stride) { 706 return WebPINewYUVA(luma, luma_size, luma_stride, 707 u, u_size, u_stride, 708 v, v_size, v_stride, 709 NULL, 0, 0); 710 } 711 712 //------------------------------------------------------------------------------ 713 714 static VP8StatusCode IDecCheckStatus(const WebPIDecoder* const idec) { 715 assert(idec); 716 if (idec->state_ == STATE_ERROR) { 717 return VP8_STATUS_BITSTREAM_ERROR; 718 } 719 if (idec->state_ == STATE_DONE) { 720 return VP8_STATUS_OK; 721 } 722 return VP8_STATUS_SUSPENDED; 723 } 724 725 VP8StatusCode WebPIAppend(WebPIDecoder* idec, 726 const uint8_t* data, size_t data_size) { 727 VP8StatusCode status; 728 if (idec == NULL || data == NULL) { 729 return VP8_STATUS_INVALID_PARAM; 730 } 731 status = IDecCheckStatus(idec); 732 if (status != VP8_STATUS_SUSPENDED) { 733 return status; 734 } 735 // Check mixed calls between RemapMemBuffer and AppendToMemBuffer. 736 if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_APPEND)) { 737 return VP8_STATUS_INVALID_PARAM; 738 } 739 // Append data to memory buffer 740 if (!AppendToMemBuffer(idec, data, data_size)) { 741 return VP8_STATUS_OUT_OF_MEMORY; 742 } 743 return IDecode(idec); 744 } 745 746 VP8StatusCode WebPIUpdate(WebPIDecoder* idec, 747 const uint8_t* data, size_t data_size) { 748 VP8StatusCode status; 749 if (idec == NULL || data == NULL) { 750 return VP8_STATUS_INVALID_PARAM; 751 } 752 status = IDecCheckStatus(idec); 753 if (status != VP8_STATUS_SUSPENDED) { 754 return status; 755 } 756 // Check mixed calls between RemapMemBuffer and AppendToMemBuffer. 757 if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_MAP)) { 758 return VP8_STATUS_INVALID_PARAM; 759 } 760 // Make the memory buffer point to the new buffer 761 if (!RemapMemBuffer(idec, data, data_size)) { 762 return VP8_STATUS_INVALID_PARAM; 763 } 764 return IDecode(idec); 765 } 766 767 //------------------------------------------------------------------------------ 768 769 static const WebPDecBuffer* GetOutputBuffer(const WebPIDecoder* const idec) { 770 if (idec == NULL || idec->dec_ == NULL) { 771 return NULL; 772 } 773 if (idec->state_ <= STATE_VP8_PARTS0) { 774 return NULL; 775 } 776 return idec->params_.output; 777 } 778 779 const WebPDecBuffer* WebPIDecodedArea(const WebPIDecoder* idec, 780 int* left, int* top, 781 int* width, int* height) { 782 const WebPDecBuffer* const src = GetOutputBuffer(idec); 783 if (left != NULL) *left = 0; 784 if (top != NULL) *top = 0; 785 // TODO(skal): later include handling of rotations. 786 if (src) { 787 if (width != NULL) *width = src->width; 788 if (height != NULL) *height = idec->params_.last_y; 789 } else { 790 if (width != NULL) *width = 0; 791 if (height != NULL) *height = 0; 792 } 793 return src; 794 } 795 796 uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y, 797 int* width, int* height, int* stride) { 798 const WebPDecBuffer* const src = GetOutputBuffer(idec); 799 if (src == NULL) return NULL; 800 if (src->colorspace >= MODE_YUV) { 801 return NULL; 802 } 803 804 if (last_y != NULL) *last_y = idec->params_.last_y; 805 if (width != NULL) *width = src->width; 806 if (height != NULL) *height = src->height; 807 if (stride != NULL) *stride = src->u.RGBA.stride; 808 809 return src->u.RGBA.rgba; 810 } 811 812 uint8_t* WebPIDecGetYUVA(const WebPIDecoder* idec, int* last_y, 813 uint8_t** u, uint8_t** v, uint8_t** a, 814 int* width, int* height, 815 int* stride, int* uv_stride, int* a_stride) { 816 const WebPDecBuffer* const src = GetOutputBuffer(idec); 817 if (src == NULL) return NULL; 818 if (src->colorspace < MODE_YUV) { 819 return NULL; 820 } 821 822 if (last_y != NULL) *last_y = idec->params_.last_y; 823 if (u != NULL) *u = src->u.YUVA.u; 824 if (v != NULL) *v = src->u.YUVA.v; 825 if (a != NULL) *a = src->u.YUVA.a; 826 if (width != NULL) *width = src->width; 827 if (height != NULL) *height = src->height; 828 if (stride != NULL) *stride = src->u.YUVA.y_stride; 829 if (uv_stride != NULL) *uv_stride = src->u.YUVA.u_stride; 830 if (a_stride != NULL) *a_stride = src->u.YUVA.a_stride; 831 832 return src->u.YUVA.y; 833 } 834 835 int WebPISetIOHooks(WebPIDecoder* const idec, 836 VP8IoPutHook put, 837 VP8IoSetupHook setup, 838 VP8IoTeardownHook teardown, 839 void* user_data) { 840 if (idec == NULL || idec->state_ > STATE_WEBP_HEADER) { 841 return 0; 842 } 843 844 idec->io_.put = put; 845 idec->io_.setup = setup; 846 idec->io_.teardown = teardown; 847 idec->io_.opaque = user_data; 848 849 return 1; 850 } 851 852
