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 "src/dec/alphai_dec.h" 19 #include "src/dec/webpi_dec.h" 20 #include "src/dec/vp8i_dec.h" 21 #include "src/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 // or if the external one has slow-memory) 75 WebPDecBuffer* final_output_; // Slow-memory output to copy to eventually. 76 size_t chunk_size_; // Compressed VP8/VP8L size extracted from Header. 77 78 int last_mb_y_; // last row reached for intra-mode decoding 79 }; 80 81 // MB context to restore in case VP8DecodeMB() fails 82 typedef struct { 83 VP8MB left_; 84 VP8MB info_; 85 VP8BitReader token_br_; 86 } MBContext; 87 88 //------------------------------------------------------------------------------ 89 // MemBuffer: incoming data handling 90 91 static WEBP_INLINE size_t MemDataSize(const MemBuffer* mem) { 92 return (mem->end_ - mem->start_); 93 } 94 95 // Check if we need to preserve the compressed alpha data, as it may not have 96 // been decoded yet. 97 static int NeedCompressedAlpha(const WebPIDecoder* const idec) { 98 if (idec->state_ == STATE_WEBP_HEADER) { 99 // We haven't parsed the headers yet, so we don't know whether the image is 100 // lossy or lossless. This also means that we haven't parsed the ALPH chunk. 101 return 0; 102 } 103 if (idec->is_lossless_) { 104 return 0; // ALPH chunk is not present for lossless images. 105 } else { 106 const VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 107 assert(dec != NULL); // Must be true as idec->state_ != STATE_WEBP_HEADER. 108 return (dec->alpha_data_ != NULL) && !dec->is_alpha_decoded_; 109 } 110 } 111 112 static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) { 113 MemBuffer* const mem = &idec->mem_; 114 const uint8_t* const new_base = mem->buf_ + mem->start_; 115 // note: for VP8, setting up idec->io_ is only really needed at the beginning 116 // of the decoding, till partition #0 is complete. 117 idec->io_.data = new_base; 118 idec->io_.data_size = MemDataSize(mem); 119 120 if (idec->dec_ != NULL) { 121 if (!idec->is_lossless_) { 122 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 123 const uint32_t last_part = dec->num_parts_minus_one_; 124 if (offset != 0) { 125 uint32_t p; 126 for (p = 0; p <= last_part; ++p) { 127 VP8RemapBitReader(dec->parts_ + p, offset); 128 } 129 // Remap partition #0 data pointer to new offset, but only in MAP 130 // mode (in APPEND mode, partition #0 is copied into a fixed memory). 131 if (mem->mode_ == MEM_MODE_MAP) { 132 VP8RemapBitReader(&dec->br_, offset); 133 } 134 } 135 { 136 const uint8_t* const last_start = dec->parts_[last_part].buf_; 137 VP8BitReaderSetBuffer(&dec->parts_[last_part], last_start, 138 mem->buf_ + mem->end_ - last_start); 139 } 140 if (NeedCompressedAlpha(idec)) { 141 ALPHDecoder* const alph_dec = dec->alph_dec_; 142 dec->alpha_data_ += offset; 143 if (alph_dec != NULL) { 144 if (alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION) { 145 VP8LDecoder* const alph_vp8l_dec = alph_dec->vp8l_dec_; 146 assert(alph_vp8l_dec != NULL); 147 assert(dec->alpha_data_size_ >= ALPHA_HEADER_LEN); 148 VP8LBitReaderSetBuffer(&alph_vp8l_dec->br_, 149 dec->alpha_data_ + ALPHA_HEADER_LEN, 150 dec->alpha_data_size_ - ALPHA_HEADER_LEN); 151 } else { // alph_dec->method_ == ALPHA_NO_COMPRESSION 152 // Nothing special to do in this case. 153 } 154 } 155 } 156 } else { // Resize lossless bitreader 157 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 158 VP8LBitReaderSetBuffer(&dec->br_, new_base, MemDataSize(mem)); 159 } 160 } 161 } 162 163 // Appends data to the end of MemBuffer->buf_. It expands the allocated memory 164 // size if required and also updates VP8BitReader's if new memory is allocated. 165 static int AppendToMemBuffer(WebPIDecoder* const idec, 166 const uint8_t* const data, size_t data_size) { 167 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 168 MemBuffer* const mem = &idec->mem_; 169 const int need_compressed_alpha = NeedCompressedAlpha(idec); 170 const uint8_t* const old_start = mem->buf_ + mem->start_; 171 const uint8_t* const old_base = 172 need_compressed_alpha ? dec->alpha_data_ : old_start; 173 assert(mem->mode_ == MEM_MODE_APPEND); 174 if (data_size > MAX_CHUNK_PAYLOAD) { 175 // security safeguard: trying to allocate more than what the format 176 // allows for a chunk should be considered a smoke smell. 177 return 0; 178 } 179 180 if (mem->end_ + data_size > mem->buf_size_) { // Need some free memory 181 const size_t new_mem_start = old_start - old_base; 182 const size_t current_size = MemDataSize(mem) + new_mem_start; 183 const uint64_t new_size = (uint64_t)current_size + data_size; 184 const uint64_t extra_size = (new_size + CHUNK_SIZE - 1) & ~(CHUNK_SIZE - 1); 185 uint8_t* const new_buf = 186 (uint8_t*)WebPSafeMalloc(extra_size, sizeof(*new_buf)); 187 if (new_buf == NULL) return 0; 188 memcpy(new_buf, old_base, current_size); 189 WebPSafeFree(mem->buf_); 190 mem->buf_ = new_buf; 191 mem->buf_size_ = (size_t)extra_size; 192 mem->start_ = new_mem_start; 193 mem->end_ = current_size; 194 } 195 196 memcpy(mem->buf_ + mem->end_, data, data_size); 197 mem->end_ += data_size; 198 assert(mem->end_ <= mem->buf_size_); 199 200 DoRemap(idec, mem->buf_ + mem->start_ - old_start); 201 return 1; 202 } 203 204 static int RemapMemBuffer(WebPIDecoder* const idec, 205 const uint8_t* const data, size_t data_size) { 206 MemBuffer* const mem = &idec->mem_; 207 const uint8_t* const old_buf = mem->buf_; 208 const uint8_t* const old_start = old_buf + mem->start_; 209 assert(mem->mode_ == MEM_MODE_MAP); 210 211 if (data_size < mem->buf_size_) return 0; // can't remap to a shorter buffer! 212 213 mem->buf_ = (uint8_t*)data; 214 mem->end_ = mem->buf_size_ = data_size; 215 216 DoRemap(idec, mem->buf_ + mem->start_ - old_start); 217 return 1; 218 } 219 220 static void InitMemBuffer(MemBuffer* const mem) { 221 mem->mode_ = MEM_MODE_NONE; 222 mem->buf_ = NULL; 223 mem->buf_size_ = 0; 224 mem->part0_buf_ = NULL; 225 mem->part0_size_ = 0; 226 } 227 228 static void ClearMemBuffer(MemBuffer* const mem) { 229 assert(mem); 230 if (mem->mode_ == MEM_MODE_APPEND) { 231 WebPSafeFree(mem->buf_); 232 WebPSafeFree((void*)mem->part0_buf_); 233 } 234 } 235 236 static int CheckMemBufferMode(MemBuffer* const mem, MemBufferMode expected) { 237 if (mem->mode_ == MEM_MODE_NONE) { 238 mem->mode_ = expected; // switch to the expected mode 239 } else if (mem->mode_ != expected) { 240 return 0; // we mixed the modes => error 241 } 242 assert(mem->mode_ == expected); // mode is ok 243 return 1; 244 } 245 246 // To be called last. 247 static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) { 248 const WebPDecoderOptions* const options = idec->params_.options; 249 WebPDecBuffer* const output = idec->params_.output; 250 251 idec->state_ = STATE_DONE; 252 if (options != NULL && options->flip) { 253 const VP8StatusCode status = WebPFlipBuffer(output); 254 if (status != VP8_STATUS_OK) return status; 255 } 256 if (idec->final_output_ != NULL) { 257 WebPCopyDecBufferPixels(output, idec->final_output_); // do the slow-copy 258 WebPFreeDecBuffer(&idec->output_); 259 *output = *idec->final_output_; 260 idec->final_output_ = NULL; 261 } 262 return VP8_STATUS_OK; 263 } 264 265 //------------------------------------------------------------------------------ 266 // Macroblock-decoding contexts 267 268 static void SaveContext(const VP8Decoder* dec, const VP8BitReader* token_br, 269 MBContext* const context) { 270 context->left_ = dec->mb_info_[-1]; 271 context->info_ = dec->mb_info_[dec->mb_x_]; 272 context->token_br_ = *token_br; 273 } 274 275 static void RestoreContext(const MBContext* context, VP8Decoder* const dec, 276 VP8BitReader* const token_br) { 277 dec->mb_info_[-1] = context->left_; 278 dec->mb_info_[dec->mb_x_] = context->info_; 279 *token_br = context->token_br_; 280 } 281 282 //------------------------------------------------------------------------------ 283 284 static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) { 285 if (idec->state_ == STATE_VP8_DATA) { 286 VP8Io* const io = &idec->io_; 287 if (io->teardown != NULL) { 288 io->teardown(io); 289 } 290 } 291 idec->state_ = STATE_ERROR; 292 return error; 293 } 294 295 static void ChangeState(WebPIDecoder* const idec, DecState new_state, 296 size_t consumed_bytes) { 297 MemBuffer* const mem = &idec->mem_; 298 idec->state_ = new_state; 299 mem->start_ += consumed_bytes; 300 assert(mem->start_ <= mem->end_); 301 idec->io_.data = mem->buf_ + mem->start_; 302 idec->io_.data_size = MemDataSize(mem); 303 } 304 305 // Headers 306 static VP8StatusCode DecodeWebPHeaders(WebPIDecoder* const idec) { 307 MemBuffer* const mem = &idec->mem_; 308 const uint8_t* data = mem->buf_ + mem->start_; 309 size_t curr_size = MemDataSize(mem); 310 VP8StatusCode status; 311 WebPHeaderStructure headers; 312 313 headers.data = data; 314 headers.data_size = curr_size; 315 headers.have_all_data = 0; 316 status = WebPParseHeaders(&headers); 317 if (status == VP8_STATUS_NOT_ENOUGH_DATA) { 318 return VP8_STATUS_SUSPENDED; // We haven't found a VP8 chunk yet. 319 } else if (status != VP8_STATUS_OK) { 320 return IDecError(idec, status); 321 } 322 323 idec->chunk_size_ = headers.compressed_size; 324 idec->is_lossless_ = headers.is_lossless; 325 if (!idec->is_lossless_) { 326 VP8Decoder* const dec = VP8New(); 327 if (dec == NULL) { 328 return VP8_STATUS_OUT_OF_MEMORY; 329 } 330 idec->dec_ = dec; 331 dec->alpha_data_ = headers.alpha_data; 332 dec->alpha_data_size_ = headers.alpha_data_size; 333 ChangeState(idec, STATE_VP8_HEADER, headers.offset); 334 } else { 335 VP8LDecoder* const dec = VP8LNew(); 336 if (dec == NULL) { 337 return VP8_STATUS_OUT_OF_MEMORY; 338 } 339 idec->dec_ = dec; 340 ChangeState(idec, STATE_VP8L_HEADER, headers.offset); 341 } 342 return VP8_STATUS_OK; 343 } 344 345 static VP8StatusCode DecodeVP8FrameHeader(WebPIDecoder* const idec) { 346 const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_; 347 const size_t curr_size = MemDataSize(&idec->mem_); 348 int width, height; 349 uint32_t bits; 350 351 if (curr_size < VP8_FRAME_HEADER_SIZE) { 352 // Not enough data bytes to extract VP8 Frame Header. 353 return VP8_STATUS_SUSPENDED; 354 } 355 if (!VP8GetInfo(data, curr_size, idec->chunk_size_, &width, &height)) { 356 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 357 } 358 359 bits = data[0] | (data[1] << 8) | (data[2] << 16); 360 idec->mem_.part0_size_ = (bits >> 5) + VP8_FRAME_HEADER_SIZE; 361 362 idec->io_.data = data; 363 idec->io_.data_size = curr_size; 364 idec->state_ = STATE_VP8_PARTS0; 365 return VP8_STATUS_OK; 366 } 367 368 // Partition #0 369 static VP8StatusCode CopyParts0Data(WebPIDecoder* const idec) { 370 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 371 VP8BitReader* const br = &dec->br_; 372 const size_t part_size = br->buf_end_ - br->buf_; 373 MemBuffer* const mem = &idec->mem_; 374 assert(!idec->is_lossless_); 375 assert(mem->part0_buf_ == NULL); 376 // the following is a format limitation, no need for runtime check: 377 assert(part_size <= mem->part0_size_); 378 if (part_size == 0) { // can't have zero-size partition #0 379 return VP8_STATUS_BITSTREAM_ERROR; 380 } 381 if (mem->mode_ == MEM_MODE_APPEND) { 382 // We copy and grab ownership of the partition #0 data. 383 uint8_t* const part0_buf = (uint8_t*)WebPSafeMalloc(1ULL, part_size); 384 if (part0_buf == NULL) { 385 return VP8_STATUS_OUT_OF_MEMORY; 386 } 387 memcpy(part0_buf, br->buf_, part_size); 388 mem->part0_buf_ = part0_buf; 389 VP8BitReaderSetBuffer(br, part0_buf, part_size); 390 } else { 391 // Else: just keep pointers to the partition #0's data in dec_->br_. 392 } 393 mem->start_ += part_size; 394 return VP8_STATUS_OK; 395 } 396 397 static VP8StatusCode DecodePartition0(WebPIDecoder* const idec) { 398 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 399 VP8Io* const io = &idec->io_; 400 const WebPDecParams* const params = &idec->params_; 401 WebPDecBuffer* const output = params->output; 402 403 // Wait till we have enough data for the whole partition #0 404 if (MemDataSize(&idec->mem_) < idec->mem_.part0_size_) { 405 return VP8_STATUS_SUSPENDED; 406 } 407 408 if (!VP8GetHeaders(dec, io)) { 409 const VP8StatusCode status = dec->status_; 410 if (status == VP8_STATUS_SUSPENDED || 411 status == VP8_STATUS_NOT_ENOUGH_DATA) { 412 // treating NOT_ENOUGH_DATA as SUSPENDED state 413 return VP8_STATUS_SUSPENDED; 414 } 415 return IDecError(idec, status); 416 } 417 418 // Allocate/Verify output buffer now 419 dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options, 420 output); 421 if (dec->status_ != VP8_STATUS_OK) { 422 return IDecError(idec, dec->status_); 423 } 424 // This change must be done before calling VP8InitFrame() 425 dec->mt_method_ = VP8GetThreadMethod(params->options, NULL, 426 io->width, io->height); 427 VP8InitDithering(params->options, dec); 428 429 dec->status_ = CopyParts0Data(idec); 430 if (dec->status_ != VP8_STATUS_OK) { 431 return IDecError(idec, dec->status_); 432 } 433 434 // Finish setting up the decoding parameters. Will call io->setup(). 435 if (VP8EnterCritical(dec, io) != VP8_STATUS_OK) { 436 return IDecError(idec, dec->status_); 437 } 438 439 // Note: past this point, teardown() must always be called 440 // in case of error. 441 idec->state_ = STATE_VP8_DATA; 442 // Allocate memory and prepare everything. 443 if (!VP8InitFrame(dec, io)) { 444 return IDecError(idec, dec->status_); 445 } 446 return VP8_STATUS_OK; 447 } 448 449 // Remaining partitions 450 static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) { 451 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 452 VP8Io* const io = &idec->io_; 453 454 assert(dec->ready_); 455 for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) { 456 if (idec->last_mb_y_ != dec->mb_y_) { 457 if (!VP8ParseIntraModeRow(&dec->br_, dec)) { 458 // note: normally, error shouldn't occur since we already have the whole 459 // partition0 available here in DecodeRemaining(). Reaching EOF while 460 // reading intra modes really means a BITSTREAM_ERROR. 461 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 462 } 463 idec->last_mb_y_ = dec->mb_y_; 464 } 465 for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) { 466 VP8BitReader* const token_br = 467 &dec->parts_[dec->mb_y_ & dec->num_parts_minus_one_]; 468 MBContext context; 469 SaveContext(dec, token_br, &context); 470 if (!VP8DecodeMB(dec, token_br)) { 471 // We shouldn't fail when MAX_MB data was available 472 if (dec->num_parts_minus_one_ == 0 && 473 MemDataSize(&idec->mem_) > MAX_MB_SIZE) { 474 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 475 } 476 RestoreContext(&context, dec, token_br); 477 return VP8_STATUS_SUSPENDED; 478 } 479 // Release buffer only if there is only one partition 480 if (dec->num_parts_minus_one_ == 0) { 481 idec->mem_.start_ = token_br->buf_ - idec->mem_.buf_; 482 assert(idec->mem_.start_ <= idec->mem_.end_); 483 } 484 } 485 VP8InitScanline(dec); // Prepare for next scanline 486 487 // Reconstruct, filter and emit the row. 488 if (!VP8ProcessRow(dec, io)) { 489 return IDecError(idec, VP8_STATUS_USER_ABORT); 490 } 491 } 492 // Synchronize the thread and check for errors. 493 if (!VP8ExitCritical(dec, io)) { 494 return IDecError(idec, VP8_STATUS_USER_ABORT); 495 } 496 dec->ready_ = 0; 497 return FinishDecoding(idec); 498 } 499 500 static VP8StatusCode ErrorStatusLossless(WebPIDecoder* const idec, 501 VP8StatusCode status) { 502 if (status == VP8_STATUS_SUSPENDED || status == VP8_STATUS_NOT_ENOUGH_DATA) { 503 return VP8_STATUS_SUSPENDED; 504 } 505 return IDecError(idec, status); 506 } 507 508 static VP8StatusCode DecodeVP8LHeader(WebPIDecoder* const idec) { 509 VP8Io* const io = &idec->io_; 510 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 511 const WebPDecParams* const params = &idec->params_; 512 WebPDecBuffer* const output = params->output; 513 size_t curr_size = MemDataSize(&idec->mem_); 514 assert(idec->is_lossless_); 515 516 // Wait until there's enough data for decoding header. 517 if (curr_size < (idec->chunk_size_ >> 3)) { 518 dec->status_ = VP8_STATUS_SUSPENDED; 519 return ErrorStatusLossless(idec, dec->status_); 520 } 521 522 if (!VP8LDecodeHeader(dec, io)) { 523 if (dec->status_ == VP8_STATUS_BITSTREAM_ERROR && 524 curr_size < idec->chunk_size_) { 525 dec->status_ = VP8_STATUS_SUSPENDED; 526 } 527 return ErrorStatusLossless(idec, dec->status_); 528 } 529 // Allocate/verify output buffer now. 530 dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options, 531 output); 532 if (dec->status_ != VP8_STATUS_OK) { 533 return IDecError(idec, dec->status_); 534 } 535 536 idec->state_ = STATE_VP8L_DATA; 537 return VP8_STATUS_OK; 538 } 539 540 static VP8StatusCode DecodeVP8LData(WebPIDecoder* const idec) { 541 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 542 const size_t curr_size = MemDataSize(&idec->mem_); 543 assert(idec->is_lossless_); 544 545 // Switch to incremental decoding if we don't have all the bytes available. 546 dec->incremental_ = (curr_size < idec->chunk_size_); 547 548 if (!VP8LDecodeImage(dec)) { 549 return ErrorStatusLossless(idec, dec->status_); 550 } 551 assert(dec->status_ == VP8_STATUS_OK || dec->status_ == VP8_STATUS_SUSPENDED); 552 return (dec->status_ == VP8_STATUS_SUSPENDED) ? dec->status_ 553 : FinishDecoding(idec); 554 } 555 556 // Main decoding loop 557 static VP8StatusCode IDecode(WebPIDecoder* idec) { 558 VP8StatusCode status = VP8_STATUS_SUSPENDED; 559 560 if (idec->state_ == STATE_WEBP_HEADER) { 561 status = DecodeWebPHeaders(idec); 562 } else { 563 if (idec->dec_ == NULL) { 564 return VP8_STATUS_SUSPENDED; // can't continue if we have no decoder. 565 } 566 } 567 if (idec->state_ == STATE_VP8_HEADER) { 568 status = DecodeVP8FrameHeader(idec); 569 } 570 if (idec->state_ == STATE_VP8_PARTS0) { 571 status = DecodePartition0(idec); 572 } 573 if (idec->state_ == STATE_VP8_DATA) { 574 status = DecodeRemaining(idec); 575 } 576 if (idec->state_ == STATE_VP8L_HEADER) { 577 status = DecodeVP8LHeader(idec); 578 } 579 if (idec->state_ == STATE_VP8L_DATA) { 580 status = DecodeVP8LData(idec); 581 } 582 return status; 583 } 584 585 //------------------------------------------------------------------------------ 586 // Internal constructor 587 588 static WebPIDecoder* NewDecoder(WebPDecBuffer* const output_buffer, 589 const WebPBitstreamFeatures* const features) { 590 WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL, sizeof(*idec)); 591 if (idec == NULL) { 592 return NULL; 593 } 594 595 idec->state_ = STATE_WEBP_HEADER; 596 idec->chunk_size_ = 0; 597 598 idec->last_mb_y_ = -1; 599 600 InitMemBuffer(&idec->mem_); 601 WebPInitDecBuffer(&idec->output_); 602 VP8InitIo(&idec->io_); 603 604 WebPResetDecParams(&idec->params_); 605 if (output_buffer == NULL || WebPAvoidSlowMemory(output_buffer, features)) { 606 idec->params_.output = &idec->output_; 607 idec->final_output_ = output_buffer; 608 if (output_buffer != NULL) { 609 idec->params_.output->colorspace = output_buffer->colorspace; 610 } 611 } else { 612 idec->params_.output = output_buffer; 613 idec->final_output_ = NULL; 614 } 615 WebPInitCustomIo(&idec->params_, &idec->io_); // Plug the I/O functions. 616 617 return idec; 618 } 619 620 //------------------------------------------------------------------------------ 621 // Public functions 622 623 WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) { 624 return NewDecoder(output_buffer, NULL); 625 } 626 627 WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size, 628 WebPDecoderConfig* config) { 629 WebPIDecoder* idec; 630 WebPBitstreamFeatures tmp_features; 631 WebPBitstreamFeatures* const features = 632 (config == NULL) ? &tmp_features : &config->input; 633 memset(&tmp_features, 0, sizeof(tmp_features)); 634 635 // Parse the bitstream's features, if requested: 636 if (data != NULL && data_size > 0) { 637 if (WebPGetFeatures(data, data_size, features) != VP8_STATUS_OK) { 638 return NULL; 639 } 640 } 641 642 // Create an instance of the incremental decoder 643 idec = (config != NULL) ? NewDecoder(&config->output, features) 644 : NewDecoder(NULL, features); 645 if (idec == NULL) { 646 return NULL; 647 } 648 // Finish initialization 649 if (config != NULL) { 650 idec->params_.options = &config->options; 651 } 652 return idec; 653 } 654 655 void WebPIDelete(WebPIDecoder* idec) { 656 if (idec == NULL) return; 657 if (idec->dec_ != NULL) { 658 if (!idec->is_lossless_) { 659 if (idec->state_ == STATE_VP8_DATA) { 660 // Synchronize the thread, clean-up and check for errors. 661 VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_); 662 } 663 VP8Delete((VP8Decoder*)idec->dec_); 664 } else { 665 VP8LDelete((VP8LDecoder*)idec->dec_); 666 } 667 } 668 ClearMemBuffer(&idec->mem_); 669 WebPFreeDecBuffer(&idec->output_); 670 WebPSafeFree(idec); 671 } 672 673 //------------------------------------------------------------------------------ 674 // Wrapper toward WebPINewDecoder 675 676 WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE csp, uint8_t* output_buffer, 677 size_t output_buffer_size, int output_stride) { 678 const int is_external_memory = (output_buffer != NULL) ? 1 : 0; 679 WebPIDecoder* idec; 680 681 if (csp >= MODE_YUV) return NULL; 682 if (is_external_memory == 0) { // Overwrite parameters to sane values. 683 output_buffer_size = 0; 684 output_stride = 0; 685 } else { // A buffer was passed. Validate the other params. 686 if (output_stride == 0 || output_buffer_size == 0) { 687 return NULL; // invalid parameter. 688 } 689 } 690 idec = WebPINewDecoder(NULL); 691 if (idec == NULL) return NULL; 692 idec->output_.colorspace = csp; 693 idec->output_.is_external_memory = is_external_memory; 694 idec->output_.u.RGBA.rgba = output_buffer; 695 idec->output_.u.RGBA.stride = output_stride; 696 idec->output_.u.RGBA.size = output_buffer_size; 697 return idec; 698 } 699 700 WebPIDecoder* WebPINewYUVA(uint8_t* luma, size_t luma_size, int luma_stride, 701 uint8_t* u, size_t u_size, int u_stride, 702 uint8_t* v, size_t v_size, int v_stride, 703 uint8_t* a, size_t a_size, int a_stride) { 704 const int is_external_memory = (luma != NULL) ? 1 : 0; 705 WebPIDecoder* idec; 706 WEBP_CSP_MODE colorspace; 707 708 if (is_external_memory == 0) { // Overwrite parameters to sane values. 709 luma_size = u_size = v_size = a_size = 0; 710 luma_stride = u_stride = v_stride = a_stride = 0; 711 u = v = a = NULL; 712 colorspace = MODE_YUVA; 713 } else { // A luma buffer was passed. Validate the other parameters. 714 if (u == NULL || v == NULL) return NULL; 715 if (luma_size == 0 || u_size == 0 || v_size == 0) return NULL; 716 if (luma_stride == 0 || u_stride == 0 || v_stride == 0) return NULL; 717 if (a != NULL) { 718 if (a_size == 0 || a_stride == 0) return NULL; 719 } 720 colorspace = (a == NULL) ? MODE_YUV : MODE_YUVA; 721 } 722 723 idec = WebPINewDecoder(NULL); 724 if (idec == NULL) return NULL; 725 726 idec->output_.colorspace = colorspace; 727 idec->output_.is_external_memory = is_external_memory; 728 idec->output_.u.YUVA.y = luma; 729 idec->output_.u.YUVA.y_stride = luma_stride; 730 idec->output_.u.YUVA.y_size = luma_size; 731 idec->output_.u.YUVA.u = u; 732 idec->output_.u.YUVA.u_stride = u_stride; 733 idec->output_.u.YUVA.u_size = u_size; 734 idec->output_.u.YUVA.v = v; 735 idec->output_.u.YUVA.v_stride = v_stride; 736 idec->output_.u.YUVA.v_size = v_size; 737 idec->output_.u.YUVA.a = a; 738 idec->output_.u.YUVA.a_stride = a_stride; 739 idec->output_.u.YUVA.a_size = a_size; 740 return idec; 741 } 742 743 WebPIDecoder* WebPINewYUV(uint8_t* luma, size_t luma_size, int luma_stride, 744 uint8_t* u, size_t u_size, int u_stride, 745 uint8_t* v, size_t v_size, int v_stride) { 746 return WebPINewYUVA(luma, luma_size, luma_stride, 747 u, u_size, u_stride, 748 v, v_size, v_stride, 749 NULL, 0, 0); 750 } 751 752 //------------------------------------------------------------------------------ 753 754 static VP8StatusCode IDecCheckStatus(const WebPIDecoder* const idec) { 755 assert(idec); 756 if (idec->state_ == STATE_ERROR) { 757 return VP8_STATUS_BITSTREAM_ERROR; 758 } 759 if (idec->state_ == STATE_DONE) { 760 return VP8_STATUS_OK; 761 } 762 return VP8_STATUS_SUSPENDED; 763 } 764 765 VP8StatusCode WebPIAppend(WebPIDecoder* idec, 766 const uint8_t* data, size_t data_size) { 767 VP8StatusCode status; 768 if (idec == NULL || data == NULL) { 769 return VP8_STATUS_INVALID_PARAM; 770 } 771 status = IDecCheckStatus(idec); 772 if (status != VP8_STATUS_SUSPENDED) { 773 return status; 774 } 775 // Check mixed calls between RemapMemBuffer and AppendToMemBuffer. 776 if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_APPEND)) { 777 return VP8_STATUS_INVALID_PARAM; 778 } 779 // Append data to memory buffer 780 if (!AppendToMemBuffer(idec, data, data_size)) { 781 return VP8_STATUS_OUT_OF_MEMORY; 782 } 783 return IDecode(idec); 784 } 785 786 VP8StatusCode WebPIUpdate(WebPIDecoder* idec, 787 const uint8_t* data, size_t data_size) { 788 VP8StatusCode status; 789 if (idec == NULL || data == NULL) { 790 return VP8_STATUS_INVALID_PARAM; 791 } 792 status = IDecCheckStatus(idec); 793 if (status != VP8_STATUS_SUSPENDED) { 794 return status; 795 } 796 // Check mixed calls between RemapMemBuffer and AppendToMemBuffer. 797 if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_MAP)) { 798 return VP8_STATUS_INVALID_PARAM; 799 } 800 // Make the memory buffer point to the new buffer 801 if (!RemapMemBuffer(idec, data, data_size)) { 802 return VP8_STATUS_INVALID_PARAM; 803 } 804 return IDecode(idec); 805 } 806 807 //------------------------------------------------------------------------------ 808 809 static const WebPDecBuffer* GetOutputBuffer(const WebPIDecoder* const idec) { 810 if (idec == NULL || idec->dec_ == NULL) { 811 return NULL; 812 } 813 if (idec->state_ <= STATE_VP8_PARTS0) { 814 return NULL; 815 } 816 if (idec->final_output_ != NULL) { 817 return NULL; // not yet slow-copied 818 } 819 return idec->params_.output; 820 } 821 822 const WebPDecBuffer* WebPIDecodedArea(const WebPIDecoder* idec, 823 int* left, int* top, 824 int* width, int* height) { 825 const WebPDecBuffer* const src = GetOutputBuffer(idec); 826 if (left != NULL) *left = 0; 827 if (top != NULL) *top = 0; 828 if (src != NULL) { 829 if (width != NULL) *width = src->width; 830 if (height != NULL) *height = idec->params_.last_y; 831 } else { 832 if (width != NULL) *width = 0; 833 if (height != NULL) *height = 0; 834 } 835 return src; 836 } 837 838 uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y, 839 int* width, int* height, int* stride) { 840 const WebPDecBuffer* const src = GetOutputBuffer(idec); 841 if (src == NULL) return NULL; 842 if (src->colorspace >= MODE_YUV) { 843 return NULL; 844 } 845 846 if (last_y != NULL) *last_y = idec->params_.last_y; 847 if (width != NULL) *width = src->width; 848 if (height != NULL) *height = src->height; 849 if (stride != NULL) *stride = src->u.RGBA.stride; 850 851 return src->u.RGBA.rgba; 852 } 853 854 uint8_t* WebPIDecGetYUVA(const WebPIDecoder* idec, int* last_y, 855 uint8_t** u, uint8_t** v, uint8_t** a, 856 int* width, int* height, 857 int* stride, int* uv_stride, int* a_stride) { 858 const WebPDecBuffer* const src = GetOutputBuffer(idec); 859 if (src == NULL) return NULL; 860 if (src->colorspace < MODE_YUV) { 861 return NULL; 862 } 863 864 if (last_y != NULL) *last_y = idec->params_.last_y; 865 if (u != NULL) *u = src->u.YUVA.u; 866 if (v != NULL) *v = src->u.YUVA.v; 867 if (a != NULL) *a = src->u.YUVA.a; 868 if (width != NULL) *width = src->width; 869 if (height != NULL) *height = src->height; 870 if (stride != NULL) *stride = src->u.YUVA.y_stride; 871 if (uv_stride != NULL) *uv_stride = src->u.YUVA.u_stride; 872 if (a_stride != NULL) *a_stride = src->u.YUVA.a_stride; 873 874 return src->u.YUVA.y; 875 } 876 877 int WebPISetIOHooks(WebPIDecoder* const idec, 878 VP8IoPutHook put, 879 VP8IoSetupHook setup, 880 VP8IoTeardownHook teardown, 881 void* user_data) { 882 if (idec == NULL || idec->state_ > STATE_WEBP_HEADER) { 883 return 0; 884 } 885 886 idec->io_.put = put; 887 idec->io_.setup = setup; 888 idec->io_.teardown = teardown; 889 idec->io_.opaque = user_data; 890 891 return 1; 892 } 893