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@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 && alph_dec->vp8l_dec_ != NULL) { 144 if (alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION) { 145 VP8LDecoder* const alph_vp8l_dec = alph_dec->vp8l_dec_; 146 assert(dec->alpha_data_size_ >= ALPHA_HEADER_LEN); 147 VP8LBitReaderSetBuffer(&alph_vp8l_dec->br_, 148 dec->alpha_data_ + ALPHA_HEADER_LEN, 149 dec->alpha_data_size_ - ALPHA_HEADER_LEN); 150 } else { // alph_dec->method_ == ALPHA_NO_COMPRESSION 151 // Nothing special to do in this case. 152 } 153 } 154 } 155 } else { // Resize lossless bitreader 156 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 157 VP8LBitReaderSetBuffer(&dec->br_, new_base, MemDataSize(mem)); 158 } 159 } 160 } 161 162 // Appends data to the end of MemBuffer->buf_. It expands the allocated memory 163 // size if required and also updates VP8BitReader's if new memory is allocated. 164 static int AppendToMemBuffer(WebPIDecoder* const idec, 165 const uint8_t* const data, size_t data_size) { 166 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 167 MemBuffer* const mem = &idec->mem_; 168 const int need_compressed_alpha = NeedCompressedAlpha(idec); 169 const uint8_t* const old_start = 170 (mem->buf_ == NULL) ? NULL : mem->buf_ + mem->start_; 171 const uint8_t* const old_base = 172 need_compressed_alpha ? dec->alpha_data_ : old_start; 173 assert(mem->buf_ != NULL || mem->start_ == 0); 174 assert(mem->mode_ == MEM_MODE_APPEND); 175 if (data_size > MAX_CHUNK_PAYLOAD) { 176 // security safeguard: trying to allocate more than what the format 177 // allows for a chunk should be considered a smoke smell. 178 return 0; 179 } 180 181 if (mem->end_ + data_size > mem->buf_size_) { // Need some free memory 182 const size_t new_mem_start = old_start - old_base; 183 const size_t current_size = MemDataSize(mem) + new_mem_start; 184 const uint64_t new_size = (uint64_t)current_size + data_size; 185 const uint64_t extra_size = (new_size + CHUNK_SIZE - 1) & ~(CHUNK_SIZE - 1); 186 uint8_t* const new_buf = 187 (uint8_t*)WebPSafeMalloc(extra_size, sizeof(*new_buf)); 188 if (new_buf == NULL) return 0; 189 if (old_base != NULL) memcpy(new_buf, old_base, current_size); 190 WebPSafeFree(mem->buf_); 191 mem->buf_ = new_buf; 192 mem->buf_size_ = (size_t)extra_size; 193 mem->start_ = new_mem_start; 194 mem->end_ = current_size; 195 } 196 197 assert(mem->buf_ != NULL); 198 memcpy(mem->buf_ + mem->end_, data, data_size); 199 mem->end_ += data_size; 200 assert(mem->end_ <= mem->buf_size_); 201 202 DoRemap(idec, mem->buf_ + mem->start_ - old_start); 203 return 1; 204 } 205 206 static int RemapMemBuffer(WebPIDecoder* const idec, 207 const uint8_t* const data, size_t data_size) { 208 MemBuffer* const mem = &idec->mem_; 209 const uint8_t* const old_buf = mem->buf_; 210 const uint8_t* const old_start = 211 (old_buf == NULL) ? NULL : old_buf + mem->start_; 212 assert(old_buf != NULL || mem->start_ == 0); 213 assert(mem->mode_ == MEM_MODE_MAP); 214 215 if (data_size < mem->buf_size_) return 0; // can't remap to a shorter buffer! 216 217 mem->buf_ = (uint8_t*)data; 218 mem->end_ = mem->buf_size_ = data_size; 219 220 DoRemap(idec, mem->buf_ + mem->start_ - old_start); 221 return 1; 222 } 223 224 static void InitMemBuffer(MemBuffer* const mem) { 225 mem->mode_ = MEM_MODE_NONE; 226 mem->buf_ = NULL; 227 mem->buf_size_ = 0; 228 mem->part0_buf_ = NULL; 229 mem->part0_size_ = 0; 230 } 231 232 static void ClearMemBuffer(MemBuffer* const mem) { 233 assert(mem); 234 if (mem->mode_ == MEM_MODE_APPEND) { 235 WebPSafeFree(mem->buf_); 236 WebPSafeFree((void*)mem->part0_buf_); 237 } 238 } 239 240 static int CheckMemBufferMode(MemBuffer* const mem, MemBufferMode expected) { 241 if (mem->mode_ == MEM_MODE_NONE) { 242 mem->mode_ = expected; // switch to the expected mode 243 } else if (mem->mode_ != expected) { 244 return 0; // we mixed the modes => error 245 } 246 assert(mem->mode_ == expected); // mode is ok 247 return 1; 248 } 249 250 // To be called last. 251 static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) { 252 const WebPDecoderOptions* const options = idec->params_.options; 253 WebPDecBuffer* const output = idec->params_.output; 254 255 idec->state_ = STATE_DONE; 256 if (options != NULL && options->flip) { 257 const VP8StatusCode status = WebPFlipBuffer(output); 258 if (status != VP8_STATUS_OK) return status; 259 } 260 if (idec->final_output_ != NULL) { 261 WebPCopyDecBufferPixels(output, idec->final_output_); // do the slow-copy 262 WebPFreeDecBuffer(&idec->output_); 263 *output = *idec->final_output_; 264 idec->final_output_ = NULL; 265 } 266 return VP8_STATUS_OK; 267 } 268 269 //------------------------------------------------------------------------------ 270 // Macroblock-decoding contexts 271 272 static void SaveContext(const VP8Decoder* dec, const VP8BitReader* token_br, 273 MBContext* const context) { 274 context->left_ = dec->mb_info_[-1]; 275 context->info_ = dec->mb_info_[dec->mb_x_]; 276 context->token_br_ = *token_br; 277 } 278 279 static void RestoreContext(const MBContext* context, VP8Decoder* const dec, 280 VP8BitReader* const token_br) { 281 dec->mb_info_[-1] = context->left_; 282 dec->mb_info_[dec->mb_x_] = context->info_; 283 *token_br = context->token_br_; 284 } 285 286 //------------------------------------------------------------------------------ 287 288 static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) { 289 if (idec->state_ == STATE_VP8_DATA) { 290 // Synchronize the thread, clean-up and check for errors. 291 VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_); 292 } 293 idec->state_ = STATE_ERROR; 294 return error; 295 } 296 297 static void ChangeState(WebPIDecoder* const idec, DecState new_state, 298 size_t consumed_bytes) { 299 MemBuffer* const mem = &idec->mem_; 300 idec->state_ = new_state; 301 mem->start_ += consumed_bytes; 302 assert(mem->start_ <= mem->end_); 303 idec->io_.data = mem->buf_ + mem->start_; 304 idec->io_.data_size = MemDataSize(mem); 305 } 306 307 // Headers 308 static VP8StatusCode DecodeWebPHeaders(WebPIDecoder* const idec) { 309 MemBuffer* const mem = &idec->mem_; 310 const uint8_t* data = mem->buf_ + mem->start_; 311 size_t curr_size = MemDataSize(mem); 312 VP8StatusCode status; 313 WebPHeaderStructure headers; 314 315 headers.data = data; 316 headers.data_size = curr_size; 317 headers.have_all_data = 0; 318 status = WebPParseHeaders(&headers); 319 if (status == VP8_STATUS_NOT_ENOUGH_DATA) { 320 return VP8_STATUS_SUSPENDED; // We haven't found a VP8 chunk yet. 321 } else if (status != VP8_STATUS_OK) { 322 return IDecError(idec, status); 323 } 324 325 idec->chunk_size_ = headers.compressed_size; 326 idec->is_lossless_ = headers.is_lossless; 327 if (!idec->is_lossless_) { 328 VP8Decoder* const dec = VP8New(); 329 if (dec == NULL) { 330 return VP8_STATUS_OUT_OF_MEMORY; 331 } 332 idec->dec_ = dec; 333 dec->alpha_data_ = headers.alpha_data; 334 dec->alpha_data_size_ = headers.alpha_data_size; 335 ChangeState(idec, STATE_VP8_HEADER, headers.offset); 336 } else { 337 VP8LDecoder* const dec = VP8LNew(); 338 if (dec == NULL) { 339 return VP8_STATUS_OUT_OF_MEMORY; 340 } 341 idec->dec_ = dec; 342 ChangeState(idec, STATE_VP8L_HEADER, headers.offset); 343 } 344 return VP8_STATUS_OK; 345 } 346 347 static VP8StatusCode DecodeVP8FrameHeader(WebPIDecoder* const idec) { 348 const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_; 349 const size_t curr_size = MemDataSize(&idec->mem_); 350 int width, height; 351 uint32_t bits; 352 353 if (curr_size < VP8_FRAME_HEADER_SIZE) { 354 // Not enough data bytes to extract VP8 Frame Header. 355 return VP8_STATUS_SUSPENDED; 356 } 357 if (!VP8GetInfo(data, curr_size, idec->chunk_size_, &width, &height)) { 358 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 359 } 360 361 bits = data[0] | (data[1] << 8) | (data[2] << 16); 362 idec->mem_.part0_size_ = (bits >> 5) + VP8_FRAME_HEADER_SIZE; 363 364 idec->io_.data = data; 365 idec->io_.data_size = curr_size; 366 idec->state_ = STATE_VP8_PARTS0; 367 return VP8_STATUS_OK; 368 } 369 370 // Partition #0 371 static VP8StatusCode CopyParts0Data(WebPIDecoder* const idec) { 372 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 373 VP8BitReader* const br = &dec->br_; 374 const size_t part_size = br->buf_end_ - br->buf_; 375 MemBuffer* const mem = &idec->mem_; 376 assert(!idec->is_lossless_); 377 assert(mem->part0_buf_ == NULL); 378 // the following is a format limitation, no need for runtime check: 379 assert(part_size <= mem->part0_size_); 380 if (part_size == 0) { // can't have zero-size partition #0 381 return VP8_STATUS_BITSTREAM_ERROR; 382 } 383 if (mem->mode_ == MEM_MODE_APPEND) { 384 // We copy and grab ownership of the partition #0 data. 385 uint8_t* const part0_buf = (uint8_t*)WebPSafeMalloc(1ULL, part_size); 386 if (part0_buf == NULL) { 387 return VP8_STATUS_OUT_OF_MEMORY; 388 } 389 memcpy(part0_buf, br->buf_, part_size); 390 mem->part0_buf_ = part0_buf; 391 VP8BitReaderSetBuffer(br, part0_buf, part_size); 392 } else { 393 // Else: just keep pointers to the partition #0's data in dec_->br_. 394 } 395 mem->start_ += part_size; 396 return VP8_STATUS_OK; 397 } 398 399 static VP8StatusCode DecodePartition0(WebPIDecoder* const idec) { 400 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 401 VP8Io* const io = &idec->io_; 402 const WebPDecParams* const params = &idec->params_; 403 WebPDecBuffer* const output = params->output; 404 405 // Wait till we have enough data for the whole partition #0 406 if (MemDataSize(&idec->mem_) < idec->mem_.part0_size_) { 407 return VP8_STATUS_SUSPENDED; 408 } 409 410 if (!VP8GetHeaders(dec, io)) { 411 const VP8StatusCode status = dec->status_; 412 if (status == VP8_STATUS_SUSPENDED || 413 status == VP8_STATUS_NOT_ENOUGH_DATA) { 414 // treating NOT_ENOUGH_DATA as SUSPENDED state 415 return VP8_STATUS_SUSPENDED; 416 } 417 return IDecError(idec, status); 418 } 419 420 // Allocate/Verify output buffer now 421 dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options, 422 output); 423 if (dec->status_ != VP8_STATUS_OK) { 424 return IDecError(idec, dec->status_); 425 } 426 // This change must be done before calling VP8InitFrame() 427 dec->mt_method_ = VP8GetThreadMethod(params->options, NULL, 428 io->width, io->height); 429 VP8InitDithering(params->options, dec); 430 431 dec->status_ = CopyParts0Data(idec); 432 if (dec->status_ != VP8_STATUS_OK) { 433 return IDecError(idec, dec->status_); 434 } 435 436 // Finish setting up the decoding parameters. Will call io->setup(). 437 if (VP8EnterCritical(dec, io) != VP8_STATUS_OK) { 438 return IDecError(idec, dec->status_); 439 } 440 441 // Note: past this point, teardown() must always be called 442 // in case of error. 443 idec->state_ = STATE_VP8_DATA; 444 // Allocate memory and prepare everything. 445 if (!VP8InitFrame(dec, io)) { 446 return IDecError(idec, dec->status_); 447 } 448 return VP8_STATUS_OK; 449 } 450 451 // Remaining partitions 452 static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) { 453 VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 454 VP8Io* const io = &idec->io_; 455 456 // Make sure partition #0 has been read before, to set dec to ready_. 457 if (!dec->ready_) { 458 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 459 } 460 for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) { 461 if (idec->last_mb_y_ != dec->mb_y_) { 462 if (!VP8ParseIntraModeRow(&dec->br_, dec)) { 463 // note: normally, error shouldn't occur since we already have the whole 464 // partition0 available here in DecodeRemaining(). Reaching EOF while 465 // reading intra modes really means a BITSTREAM_ERROR. 466 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 467 } 468 idec->last_mb_y_ = dec->mb_y_; 469 } 470 for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) { 471 VP8BitReader* const token_br = 472 &dec->parts_[dec->mb_y_ & dec->num_parts_minus_one_]; 473 MBContext context; 474 SaveContext(dec, token_br, &context); 475 if (!VP8DecodeMB(dec, token_br)) { 476 // We shouldn't fail when MAX_MB data was available 477 if (dec->num_parts_minus_one_ == 0 && 478 MemDataSize(&idec->mem_) > MAX_MB_SIZE) { 479 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 480 } 481 // Synchronize the threads. 482 if (dec->mt_method_ > 0) { 483 if (!WebPGetWorkerInterface()->Sync(&dec->worker_)) { 484 return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); 485 } 486 } 487 RestoreContext(&context, dec, token_br); 488 return VP8_STATUS_SUSPENDED; 489 } 490 // Release buffer only if there is only one partition 491 if (dec->num_parts_minus_one_ == 0) { 492 idec->mem_.start_ = token_br->buf_ - idec->mem_.buf_; 493 assert(idec->mem_.start_ <= idec->mem_.end_); 494 } 495 } 496 VP8InitScanline(dec); // Prepare for next scanline 497 498 // Reconstruct, filter and emit the row. 499 if (!VP8ProcessRow(dec, io)) { 500 return IDecError(idec, VP8_STATUS_USER_ABORT); 501 } 502 } 503 // Synchronize the thread and check for errors. 504 if (!VP8ExitCritical(dec, io)) { 505 idec->state_ = STATE_ERROR; // prevent re-entry in IDecError 506 return IDecError(idec, VP8_STATUS_USER_ABORT); 507 } 508 dec->ready_ = 0; 509 return FinishDecoding(idec); 510 } 511 512 static VP8StatusCode ErrorStatusLossless(WebPIDecoder* const idec, 513 VP8StatusCode status) { 514 if (status == VP8_STATUS_SUSPENDED || status == VP8_STATUS_NOT_ENOUGH_DATA) { 515 return VP8_STATUS_SUSPENDED; 516 } 517 return IDecError(idec, status); 518 } 519 520 static VP8StatusCode DecodeVP8LHeader(WebPIDecoder* const idec) { 521 VP8Io* const io = &idec->io_; 522 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 523 const WebPDecParams* const params = &idec->params_; 524 WebPDecBuffer* const output = params->output; 525 size_t curr_size = MemDataSize(&idec->mem_); 526 assert(idec->is_lossless_); 527 528 // Wait until there's enough data for decoding header. 529 if (curr_size < (idec->chunk_size_ >> 3)) { 530 dec->status_ = VP8_STATUS_SUSPENDED; 531 return ErrorStatusLossless(idec, dec->status_); 532 } 533 534 if (!VP8LDecodeHeader(dec, io)) { 535 if (dec->status_ == VP8_STATUS_BITSTREAM_ERROR && 536 curr_size < idec->chunk_size_) { 537 dec->status_ = VP8_STATUS_SUSPENDED; 538 } 539 return ErrorStatusLossless(idec, dec->status_); 540 } 541 // Allocate/verify output buffer now. 542 dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options, 543 output); 544 if (dec->status_ != VP8_STATUS_OK) { 545 return IDecError(idec, dec->status_); 546 } 547 548 idec->state_ = STATE_VP8L_DATA; 549 return VP8_STATUS_OK; 550 } 551 552 static VP8StatusCode DecodeVP8LData(WebPIDecoder* const idec) { 553 VP8LDecoder* const dec = (VP8LDecoder*)idec->dec_; 554 const size_t curr_size = MemDataSize(&idec->mem_); 555 assert(idec->is_lossless_); 556 557 // Switch to incremental decoding if we don't have all the bytes available. 558 dec->incremental_ = (curr_size < idec->chunk_size_); 559 560 if (!VP8LDecodeImage(dec)) { 561 return ErrorStatusLossless(idec, dec->status_); 562 } 563 assert(dec->status_ == VP8_STATUS_OK || dec->status_ == VP8_STATUS_SUSPENDED); 564 return (dec->status_ == VP8_STATUS_SUSPENDED) ? dec->status_ 565 : FinishDecoding(idec); 566 } 567 568 // Main decoding loop 569 static VP8StatusCode IDecode(WebPIDecoder* idec) { 570 VP8StatusCode status = VP8_STATUS_SUSPENDED; 571 572 if (idec->state_ == STATE_WEBP_HEADER) { 573 status = DecodeWebPHeaders(idec); 574 } else { 575 if (idec->dec_ == NULL) { 576 return VP8_STATUS_SUSPENDED; // can't continue if we have no decoder. 577 } 578 } 579 if (idec->state_ == STATE_VP8_HEADER) { 580 status = DecodeVP8FrameHeader(idec); 581 } 582 if (idec->state_ == STATE_VP8_PARTS0) { 583 status = DecodePartition0(idec); 584 } 585 if (idec->state_ == STATE_VP8_DATA) { 586 const VP8Decoder* const dec = (VP8Decoder*)idec->dec_; 587 if (dec == NULL) { 588 return VP8_STATUS_SUSPENDED; // can't continue if we have no decoder. 589 } 590 status = DecodeRemaining(idec); 591 } 592 if (idec->state_ == STATE_VP8L_HEADER) { 593 status = DecodeVP8LHeader(idec); 594 } 595 if (idec->state_ == STATE_VP8L_DATA) { 596 status = DecodeVP8LData(idec); 597 } 598 return status; 599 } 600 601 //------------------------------------------------------------------------------ 602 // Internal constructor 603 604 static WebPIDecoder* NewDecoder(WebPDecBuffer* const output_buffer, 605 const WebPBitstreamFeatures* const features) { 606 WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL, sizeof(*idec)); 607 if (idec == NULL) { 608 return NULL; 609 } 610 611 idec->state_ = STATE_WEBP_HEADER; 612 idec->chunk_size_ = 0; 613 614 idec->last_mb_y_ = -1; 615 616 InitMemBuffer(&idec->mem_); 617 WebPInitDecBuffer(&idec->output_); 618 VP8InitIo(&idec->io_); 619 620 WebPResetDecParams(&idec->params_); 621 if (output_buffer == NULL || WebPAvoidSlowMemory(output_buffer, features)) { 622 idec->params_.output = &idec->output_; 623 idec->final_output_ = output_buffer; 624 if (output_buffer != NULL) { 625 idec->params_.output->colorspace = output_buffer->colorspace; 626 } 627 } else { 628 idec->params_.output = output_buffer; 629 idec->final_output_ = NULL; 630 } 631 WebPInitCustomIo(&idec->params_, &idec->io_); // Plug the I/O functions. 632 633 return idec; 634 } 635 636 //------------------------------------------------------------------------------ 637 // Public functions 638 639 WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) { 640 return NewDecoder(output_buffer, NULL); 641 } 642 643 WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size, 644 WebPDecoderConfig* config) { 645 WebPIDecoder* idec; 646 WebPBitstreamFeatures tmp_features; 647 WebPBitstreamFeatures* const features = 648 (config == NULL) ? &tmp_features : &config->input; 649 memset(&tmp_features, 0, sizeof(tmp_features)); 650 651 // Parse the bitstream's features, if requested: 652 if (data != NULL && data_size > 0) { 653 if (WebPGetFeatures(data, data_size, features) != VP8_STATUS_OK) { 654 return NULL; 655 } 656 } 657 658 // Create an instance of the incremental decoder 659 idec = (config != NULL) ? NewDecoder(&config->output, features) 660 : NewDecoder(NULL, features); 661 if (idec == NULL) { 662 return NULL; 663 } 664 // Finish initialization 665 if (config != NULL) { 666 idec->params_.options = &config->options; 667 } 668 return idec; 669 } 670 671 void WebPIDelete(WebPIDecoder* idec) { 672 if (idec == NULL) return; 673 if (idec->dec_ != NULL) { 674 if (!idec->is_lossless_) { 675 if (idec->state_ == STATE_VP8_DATA) { 676 // Synchronize the thread, clean-up and check for errors. 677 VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_); 678 } 679 VP8Delete((VP8Decoder*)idec->dec_); 680 } else { 681 VP8LDelete((VP8LDecoder*)idec->dec_); 682 } 683 } 684 ClearMemBuffer(&idec->mem_); 685 WebPFreeDecBuffer(&idec->output_); 686 WebPSafeFree(idec); 687 } 688 689 //------------------------------------------------------------------------------ 690 // Wrapper toward WebPINewDecoder 691 692 WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE csp, uint8_t* output_buffer, 693 size_t output_buffer_size, int output_stride) { 694 const int is_external_memory = (output_buffer != NULL) ? 1 : 0; 695 WebPIDecoder* idec; 696 697 if (csp >= MODE_YUV) return NULL; 698 if (is_external_memory == 0) { // Overwrite parameters to sane values. 699 output_buffer_size = 0; 700 output_stride = 0; 701 } else { // A buffer was passed. Validate the other params. 702 if (output_stride == 0 || output_buffer_size == 0) { 703 return NULL; // invalid parameter. 704 } 705 } 706 idec = WebPINewDecoder(NULL); 707 if (idec == NULL) return NULL; 708 idec->output_.colorspace = csp; 709 idec->output_.is_external_memory = is_external_memory; 710 idec->output_.u.RGBA.rgba = output_buffer; 711 idec->output_.u.RGBA.stride = output_stride; 712 idec->output_.u.RGBA.size = output_buffer_size; 713 return idec; 714 } 715 716 WebPIDecoder* WebPINewYUVA(uint8_t* luma, size_t luma_size, int luma_stride, 717 uint8_t* u, size_t u_size, int u_stride, 718 uint8_t* v, size_t v_size, int v_stride, 719 uint8_t* a, size_t a_size, int a_stride) { 720 const int is_external_memory = (luma != NULL) ? 1 : 0; 721 WebPIDecoder* idec; 722 WEBP_CSP_MODE colorspace; 723 724 if (is_external_memory == 0) { // Overwrite parameters to sane values. 725 luma_size = u_size = v_size = a_size = 0; 726 luma_stride = u_stride = v_stride = a_stride = 0; 727 u = v = a = NULL; 728 colorspace = MODE_YUVA; 729 } else { // A luma buffer was passed. Validate the other parameters. 730 if (u == NULL || v == NULL) return NULL; 731 if (luma_size == 0 || u_size == 0 || v_size == 0) return NULL; 732 if (luma_stride == 0 || u_stride == 0 || v_stride == 0) return NULL; 733 if (a != NULL) { 734 if (a_size == 0 || a_stride == 0) return NULL; 735 } 736 colorspace = (a == NULL) ? MODE_YUV : MODE_YUVA; 737 } 738 739 idec = WebPINewDecoder(NULL); 740 if (idec == NULL) return NULL; 741 742 idec->output_.colorspace = colorspace; 743 idec->output_.is_external_memory = is_external_memory; 744 idec->output_.u.YUVA.y = luma; 745 idec->output_.u.YUVA.y_stride = luma_stride; 746 idec->output_.u.YUVA.y_size = luma_size; 747 idec->output_.u.YUVA.u = u; 748 idec->output_.u.YUVA.u_stride = u_stride; 749 idec->output_.u.YUVA.u_size = u_size; 750 idec->output_.u.YUVA.v = v; 751 idec->output_.u.YUVA.v_stride = v_stride; 752 idec->output_.u.YUVA.v_size = v_size; 753 idec->output_.u.YUVA.a = a; 754 idec->output_.u.YUVA.a_stride = a_stride; 755 idec->output_.u.YUVA.a_size = a_size; 756 return idec; 757 } 758 759 WebPIDecoder* WebPINewYUV(uint8_t* luma, size_t luma_size, int luma_stride, 760 uint8_t* u, size_t u_size, int u_stride, 761 uint8_t* v, size_t v_size, int v_stride) { 762 return WebPINewYUVA(luma, luma_size, luma_stride, 763 u, u_size, u_stride, 764 v, v_size, v_stride, 765 NULL, 0, 0); 766 } 767 768 //------------------------------------------------------------------------------ 769 770 static VP8StatusCode IDecCheckStatus(const WebPIDecoder* const idec) { 771 assert(idec); 772 if (idec->state_ == STATE_ERROR) { 773 return VP8_STATUS_BITSTREAM_ERROR; 774 } 775 if (idec->state_ == STATE_DONE) { 776 return VP8_STATUS_OK; 777 } 778 return VP8_STATUS_SUSPENDED; 779 } 780 781 VP8StatusCode WebPIAppend(WebPIDecoder* idec, 782 const uint8_t* data, size_t data_size) { 783 VP8StatusCode status; 784 if (idec == NULL || data == NULL) { 785 return VP8_STATUS_INVALID_PARAM; 786 } 787 status = IDecCheckStatus(idec); 788 if (status != VP8_STATUS_SUSPENDED) { 789 return status; 790 } 791 // Check mixed calls between RemapMemBuffer and AppendToMemBuffer. 792 if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_APPEND)) { 793 return VP8_STATUS_INVALID_PARAM; 794 } 795 // Append data to memory buffer 796 if (!AppendToMemBuffer(idec, data, data_size)) { 797 return VP8_STATUS_OUT_OF_MEMORY; 798 } 799 return IDecode(idec); 800 } 801 802 VP8StatusCode WebPIUpdate(WebPIDecoder* idec, 803 const uint8_t* data, size_t data_size) { 804 VP8StatusCode status; 805 if (idec == NULL || data == NULL) { 806 return VP8_STATUS_INVALID_PARAM; 807 } 808 status = IDecCheckStatus(idec); 809 if (status != VP8_STATUS_SUSPENDED) { 810 return status; 811 } 812 // Check mixed calls between RemapMemBuffer and AppendToMemBuffer. 813 if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_MAP)) { 814 return VP8_STATUS_INVALID_PARAM; 815 } 816 // Make the memory buffer point to the new buffer 817 if (!RemapMemBuffer(idec, data, data_size)) { 818 return VP8_STATUS_INVALID_PARAM; 819 } 820 return IDecode(idec); 821 } 822 823 //------------------------------------------------------------------------------ 824 825 static const WebPDecBuffer* GetOutputBuffer(const WebPIDecoder* const idec) { 826 if (idec == NULL || idec->dec_ == NULL) { 827 return NULL; 828 } 829 if (idec->state_ <= STATE_VP8_PARTS0) { 830 return NULL; 831 } 832 if (idec->final_output_ != NULL) { 833 return NULL; // not yet slow-copied 834 } 835 return idec->params_.output; 836 } 837 838 const WebPDecBuffer* WebPIDecodedArea(const WebPIDecoder* idec, 839 int* left, int* top, 840 int* width, int* height) { 841 const WebPDecBuffer* const src = GetOutputBuffer(idec); 842 if (left != NULL) *left = 0; 843 if (top != NULL) *top = 0; 844 if (src != NULL) { 845 if (width != NULL) *width = src->width; 846 if (height != NULL) *height = idec->params_.last_y; 847 } else { 848 if (width != NULL) *width = 0; 849 if (height != NULL) *height = 0; 850 } 851 return src; 852 } 853 854 uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y, 855 int* width, int* height, int* stride) { 856 const WebPDecBuffer* const src = GetOutputBuffer(idec); 857 if (src == NULL) return NULL; 858 if (src->colorspace >= MODE_YUV) { 859 return NULL; 860 } 861 862 if (last_y != NULL) *last_y = idec->params_.last_y; 863 if (width != NULL) *width = src->width; 864 if (height != NULL) *height = src->height; 865 if (stride != NULL) *stride = src->u.RGBA.stride; 866 867 return src->u.RGBA.rgba; 868 } 869 870 uint8_t* WebPIDecGetYUVA(const WebPIDecoder* idec, int* last_y, 871 uint8_t** u, uint8_t** v, uint8_t** a, 872 int* width, int* height, 873 int* stride, int* uv_stride, int* a_stride) { 874 const WebPDecBuffer* const src = GetOutputBuffer(idec); 875 if (src == NULL) return NULL; 876 if (src->colorspace < MODE_YUV) { 877 return NULL; 878 } 879 880 if (last_y != NULL) *last_y = idec->params_.last_y; 881 if (u != NULL) *u = src->u.YUVA.u; 882 if (v != NULL) *v = src->u.YUVA.v; 883 if (a != NULL) *a = src->u.YUVA.a; 884 if (width != NULL) *width = src->width; 885 if (height != NULL) *height = src->height; 886 if (stride != NULL) *stride = src->u.YUVA.y_stride; 887 if (uv_stride != NULL) *uv_stride = src->u.YUVA.u_stride; 888 if (a_stride != NULL) *a_stride = src->u.YUVA.a_stride; 889 890 return src->u.YUVA.y; 891 } 892 893 int WebPISetIOHooks(WebPIDecoder* const idec, 894 VP8IoPutHook put, 895 VP8IoSetupHook setup, 896 VP8IoTeardownHook teardown, 897 void* user_data) { 898 if (idec == NULL || idec->state_ > STATE_WEBP_HEADER) { 899 return 0; 900 } 901 902 idec->io_.put = put; 903 idec->io_.setup = setup; 904 idec->io_.teardown = teardown; 905 idec->io_.opaque = user_data; 906 907 return 1; 908 } 909