// Copyright 2011 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Incremental decoding
//
// Author: somnath@google.com (Somnath Banerjee)
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include "src/dec/alphai_dec.h"
#include "src/dec/webpi_dec.h"
#include "src/dec/vp8_dec.h"
#include "src/dec/vp8i_dec.h"
#include "src/utils/utils.h"
#include "src/webp/decode.h"
// In append mode, buffer allocations increase as multiples of this value.
// Needs to be a power of 2.
#define CHUNK_SIZE 4096
#define MAX_MB_SIZE 4096
//------------------------------------------------------------------------------
// Data structures for memory and states
// Decoding states. State normally flows as:
// WEBP_HEADER->VP8_HEADER->VP8_PARTS0->VP8_DATA->DONE for a lossy image, and
// WEBP_HEADER->VP8L_HEADER->VP8L_DATA->DONE for a lossless image.
// If there is any error the decoder goes into state ERROR.
typedef enum {
STATE_WEBP_HEADER,
// All the data before that of the VP8/VP8L chunk.
STATE_VP8_HEADER,
// The VP8 Frame header (within the VP8 chunk).
STATE_VP8_PARTS0,
STATE_VP8_DATA,
STATE_VP8L_HEADER,
STATE_VP8L_DATA,
STATE_DONE,
STATE_ERROR
} DecState;
// Operating state for the MemBuffer
typedef enum {
MEM_MODE_NONE = 0,
MEM_MODE_APPEND,
MEM_MODE_MAP
} MemBufferMode;
// storage for partition #0 and partial data (in a rolling fashion)
typedef struct {
MemBufferMode mode_;
// Operation mode
size_t start_;
// start location of the data to be decoded
size_t end_;
// end location
size_t buf_size_;
// size of the allocated buffer
uint8_t* buf_;
// We don't own this buffer in case WebPIUpdate()
size_t part0_size_;
// size of partition #0
const uint8_t* part0_buf_;
// buffer to store partition #0
} MemBuffer;
struct WebPIDecoder {
DecState state_;
// current decoding state
WebPDecParams params_;
// Params to store output info
int is_lossless_;
// for down-casting 'dec_'.
void* dec_;
// either a VP8Decoder or a VP8LDecoder instance
VP8Io io_;
MemBuffer mem_;
// input memory buffer.
WebPDecBuffer output_;
// output buffer (when no external one is supplied,
// or if the external one has slow-memory)
WebPDecBuffer* final_output_;
// Slow-memory output to copy to eventually.
size_t chunk_size_;
// Compressed VP8/VP8L size extracted from Header.
int last_mb_y_;
// last row reached for intra-mode decoding
};
// MB context to restore in case VP8DecodeMB() fails
typedef struct {
VP8MB left_;
VP8MB info_;
VP8BitReader token_br_;
} MBContext;
//------------------------------------------------------------------------------
// MemBuffer: incoming data handling
static WEBP_INLINE size_t MemDataSize(
const MemBuffer* mem) {
return (mem->end_ - mem->start_);
}
// Check if we need to preserve the compressed alpha data, as it may not have
// been decoded yet.
static int NeedCompressedAlpha(
const WebPIDecoder*
const idec) {
if (idec->state_ == STATE_WEBP_HEADER) {
// We haven't parsed the headers yet, so we don't know whether the image is
// lossy or lossless. This also means that we haven't parsed the ALPH chunk.
return 0;
}
if (idec->is_lossless_) {
return 0;
// ALPH chunk is not present for lossless images.
}
else {
const VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
assert(dec != NULL);
// Must be true as idec->state_ != STATE_WEBP_HEADER.
return (dec->alpha_data_ != NULL) && !dec->is_alpha_decoded_;
}
}
static void DoRemap(WebPIDecoder*
const idec, ptrdiff_t offset) {
MemBuffer*
const mem = &idec->mem_;
const uint8_t*
const new_base = mem->buf_ + mem->start_;
// note: for VP8, setting up idec->io_ is only really needed at the beginning
// of the decoding, till partition #0 is complete.
idec->io_.data = new_base;
idec->io_.data_size = MemDataSize(mem);
if (idec->dec_ != NULL) {
if (!idec->is_lossless_) {
VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
const uint32_t last_part = dec->num_parts_minus_one_;
if (offset != 0) {
uint32_t p;
for (p = 0; p <= last_part; ++p) {
VP8RemapBitReader(dec->parts_ + p, offset);
}
// Remap partition #0 data pointer to new offset, but only in MAP
// mode (in APPEND mode, partition #0 is copied into a fixed memory).
if (mem->mode_ == MEM_MODE_MAP) {
VP8RemapBitReader(&dec->br_, offset);
}
}
{
const uint8_t*
const last_start = dec->parts_[last_part].buf_;
VP8BitReaderSetBuffer(&dec->parts_[last_part], last_start,
mem->buf_ + mem->end_ - last_start);
}
if (NeedCompressedAlpha(idec)) {
ALPHDecoder*
const alph_dec = dec->alph_dec_;
dec->alpha_data_ += offset;
if (alph_dec != NULL && alph_dec->vp8l_dec_ != NULL) {
if (alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION) {
VP8LDecoder*
const alph_vp8l_dec = alph_dec->vp8l_dec_;
assert(dec->alpha_data_size_ >= ALPHA_HEADER_LEN);
VP8LBitReaderSetBuffer(&alph_vp8l_dec->br_,
dec->alpha_data_ + ALPHA_HEADER_LEN,
dec->alpha_data_size_ - ALPHA_HEADER_LEN);
}
else {
// alph_dec->method_ == ALPHA_NO_COMPRESSION
// Nothing special to do in this case.
}
}
}
}
else {
// Resize lossless bitreader
VP8LDecoder*
const dec = (VP8LDecoder*)idec->dec_;
VP8LBitReaderSetBuffer(&dec->br_, new_base, MemDataSize(mem));
}
}
}
// Appends data to the end of MemBuffer->buf_. It expands the allocated memory
// size if required and also updates VP8BitReader's if new memory is allocated.
WEBP_NODISCARD
static int AppendToMemBuffer(WebPIDecoder*
const idec,
const uint8_t*
const data,
size_t data_size) {
VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
MemBuffer*
const mem = &idec->mem_;
const int need_compressed_alpha = NeedCompressedAlpha(idec);
const uint8_t*
const old_start =
(mem->buf_ == NULL) ? NULL : mem->buf_ + mem->start_;
const uint8_t*
const old_base =
need_compressed_alpha ? dec->alpha_data_ : old_start;
assert(mem->buf_ != NULL || mem->start_ == 0);
assert(mem->mode_ == MEM_MODE_APPEND);
if (data_size > MAX_CHUNK_PAYLOAD) {
// security safeguard: trying to allocate more than what the format
// allows for a chunk should be considered a smoke smell.
return 0;
}
if (mem->end_ + data_size > mem->buf_size_) {
// Need some free memory
const size_t new_mem_start = old_start - old_base;
const size_t current_size = MemDataSize(mem) + new_mem_start;
const uint64_t new_size = (uint64_t)current_size + data_size;
const uint64_t extra_size = (new_size + CHUNK_SIZE - 1) & ~(CHUNK_SIZE - 1);
uint8_t*
const new_buf =
(uint8_t*)WebPSafeMalloc(extra_size,
sizeof(*new_buf));
if (new_buf == NULL)
return 0;
if (old_base != NULL) memcpy(new_buf, old_base, current_size);
WebPSafeFree(mem->buf_);
mem->buf_ = new_buf;
mem->buf_size_ = (size_t)extra_size;
mem->start_ = new_mem_start;
mem->end_ = current_size;
}
assert(mem->buf_ != NULL);
memcpy(mem->buf_ + mem->end_, data, data_size);
mem->end_ += data_size;
assert(mem->end_ <= mem->buf_size_);
DoRemap(idec, mem->buf_ + mem->start_ - old_start);
return 1;
}
WEBP_NODISCARD
static int RemapMemBuffer(WebPIDecoder*
const idec,
const uint8_t*
const data,
size_t data_size) {
MemBuffer*
const mem = &idec->mem_;
const uint8_t*
const old_buf = mem->buf_;
const uint8_t*
const old_start =
(old_buf == NULL) ? NULL : old_buf + mem->start_;
assert(old_buf != NULL || mem->start_ == 0);
assert(mem->mode_ == MEM_MODE_MAP);
if (data_size < mem->buf_size_)
return 0;
// can't remap to a shorter buffer!
mem->buf_ = (uint8_t*)data;
mem->end_ = mem->buf_size_ = data_size;
DoRemap(idec, mem->buf_ + mem->start_ - old_start);
return 1;
}
static void InitMemBuffer(MemBuffer*
const mem) {
mem->mode_ = MEM_MODE_NONE;
mem->buf_ = NULL;
mem->buf_size_ = 0;
mem->part0_buf_ = NULL;
mem->part0_size_ = 0;
}
static void ClearMemBuffer(MemBuffer*
const mem) {
assert(mem);
if (mem->mode_ == MEM_MODE_APPEND) {
WebPSafeFree(mem->buf_);
WebPSafeFree((
void*)mem->part0_buf_);
}
}
WEBP_NODISCARD
static int CheckMemBufferMode(MemBuffer*
const mem,
MemBufferMode expected) {
if (mem->mode_ == MEM_MODE_NONE) {
mem->mode_ = expected;
// switch to the expected mode
}
else if (mem->mode_ != expected) {
return 0;
// we mixed the modes => error
}
assert(mem->mode_ == expected);
// mode is ok
return 1;
}
// To be called last.
WEBP_NODISCARD
static VP8StatusCode FinishDecoding(WebPIDecoder*
const idec) {
const WebPDecoderOptions*
const options = idec->params_.options;
WebPDecBuffer*
const output = idec->params_.output;
idec->state_ = STATE_DONE;
if (options != NULL && options->flip) {
const VP8StatusCode status = WebPFlipBuffer(output);
if (status != VP8_STATUS_OK)
return status;
}
if (idec->final_output_ != NULL) {
const VP8StatusCode status = WebPCopyDecBufferPixels(
output, idec->final_output_);
// do the slow-copy
WebPFreeDecBuffer(&idec->output_);
if (status != VP8_STATUS_OK)
return status;
*output = *idec->final_output_;
idec->final_output_ = NULL;
}
return VP8_STATUS_OK;
}
//------------------------------------------------------------------------------
// Macroblock-decoding contexts
static void SaveContext(
const VP8Decoder* dec,
const VP8BitReader* token_br,
MBContext*
const context) {
context->left_ = dec->mb_info_[-1];
context->info_ = dec->mb_info_[dec->mb_x_];
context->token_br_ = *token_br;
}
static void RestoreContext(
const MBContext* context, VP8Decoder*
const dec,
VP8BitReader*
const token_br) {
dec->mb_info_[-1] = context->left_;
dec->mb_info_[dec->mb_x_] = context->info_;
*token_br = context->token_br_;
}
//------------------------------------------------------------------------------
static VP8StatusCode IDecError(WebPIDecoder*
const idec, VP8StatusCode error) {
if (idec->state_ == STATE_VP8_DATA) {
// Synchronize the thread, clean-up and check for errors.
(
void)VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
}
idec->state_ = STATE_ERROR;
return error;
}
static void ChangeState(WebPIDecoder*
const idec, DecState new_state,
size_t consumed_bytes) {
MemBuffer*
const mem = &idec->mem_;
idec->state_ = new_state;
mem->start_ += consumed_bytes;
assert(mem->start_ <= mem->end_);
idec->io_.data = mem->buf_ + mem->start_;
idec->io_.data_size = MemDataSize(mem);
}
// Headers
static VP8StatusCode DecodeWebPHeaders(WebPIDecoder*
const idec) {
MemBuffer*
const mem = &idec->mem_;
const uint8_t* data = mem->buf_ + mem->start_;
size_t curr_size = MemDataSize(mem);
VP8StatusCode status;
WebPHeaderStructure headers;
headers.data = data;
headers.data_size = curr_size;
headers.have_all_data = 0;
status = WebPParseHeaders(&headers);
if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_SUSPENDED;
// We haven't found a VP8 chunk yet.
}
else if (status != VP8_STATUS_OK) {
return IDecError(idec, status);
}
idec->chunk_size_ = headers.compressed_size;
idec->is_lossless_ = headers.is_lossless;
if (!idec->is_lossless_) {
VP8Decoder*
const dec = VP8New();
if (dec == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
dec->incremental_ = 1;
idec->dec_ = dec;
dec->alpha_data_ = headers.alpha_data;
dec->alpha_data_size_ = headers.alpha_data_size;
ChangeState(idec, STATE_VP8_HEADER, headers.offset);
}
else {
VP8LDecoder*
const dec = VP8LNew();
if (dec == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
idec->dec_ = dec;
ChangeState(idec, STATE_VP8L_HEADER, headers.offset);
}
return VP8_STATUS_OK;
}
static VP8StatusCode DecodeVP8FrameHeader(WebPIDecoder*
const idec) {
const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_;
const size_t curr_size = MemDataSize(&idec->mem_);
int width, height;
uint32_t bits;
if (curr_size < VP8_FRAME_HEADER_SIZE) {
// Not enough data bytes to extract VP8 Frame Header.
return VP8_STATUS_SUSPENDED;
}
if (!VP8GetInfo(data, curr_size, idec->chunk_size_, &width, &height)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
bits = data[0] | (data[1] << 8) | (data[2] << 16);
idec->mem_.part0_size_ = (bits >> 5) + VP8_FRAME_HEADER_SIZE;
idec->io_.data = data;
idec->io_.data_size = curr_size;
idec->state_ = STATE_VP8_PARTS0;
return VP8_STATUS_OK;
}
// Partition #0
static VP8StatusCode CopyParts0Data(WebPIDecoder*
const idec) {
VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
VP8BitReader*
const br = &dec->br_;
const size_t part_size = br->buf_end_ - br->buf_;
MemBuffer*
const mem = &idec->mem_;
assert(!idec->is_lossless_);
assert(mem->part0_buf_ == NULL);
// the following is a format limitation, no need for runtime check:
assert(part_size <= mem->part0_size_);
if (part_size == 0) {
// can't have zero-size partition #0
return VP8_STATUS_BITSTREAM_ERROR;
}
if (mem->mode_ == MEM_MODE_APPEND) {
// We copy and grab ownership of the partition #0 data.
uint8_t*
const part0_buf = (uint8_t*)WebPSafeMalloc(1ULL, part_size);
if (part0_buf == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
memcpy(part0_buf, br->buf_, part_size);
mem->part0_buf_ = part0_buf;
VP8BitReaderSetBuffer(br, part0_buf, part_size);
}
else {
// Else: just keep pointers to the partition #0's data in dec_->br_.
}
mem->start_ += part_size;
return VP8_STATUS_OK;
}
static VP8StatusCode DecodePartition0(WebPIDecoder*
const idec) {
VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
VP8Io*
const io = &idec->io_;
const WebPDecParams*
const params = &idec->params_;
WebPDecBuffer*
const output = params->output;
// Wait till we have enough data for the whole partition #0
if (MemDataSize(&idec->mem_) < idec->mem_.part0_size_) {
return VP8_STATUS_SUSPENDED;
}
if (!VP8GetHeaders(dec, io)) {
const VP8StatusCode status = dec->status_;
if (status == VP8_STATUS_SUSPENDED ||
status == VP8_STATUS_NOT_ENOUGH_DATA) {
// treating NOT_ENOUGH_DATA as SUSPENDED state
return VP8_STATUS_SUSPENDED;
}
return IDecError(idec, status);
}
// Allocate/Verify output buffer now
dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options,
output);
if (dec->status_ != VP8_STATUS_OK) {
return IDecError(idec, dec->status_);
}
// This change must be done before calling VP8InitFrame()
dec->mt_method_ = VP8GetThreadMethod(params->options, NULL,
io->width, io->height);
VP8InitDithering(params->options, dec);
dec->status_ = CopyParts0Data(idec);
if (dec->status_ != VP8_STATUS_OK) {
return IDecError(idec, dec->status_);
}
// Finish setting up the decoding parameters. Will call io->setup().
if (VP8EnterCritical(dec, io) != VP8_STATUS_OK) {
return IDecError(idec, dec->status_);
}
// Note: past this point, teardown() must always be called
// in case of error.
idec->state_ = STATE_VP8_DATA;
// Allocate memory and prepare everything.
if (!VP8InitFrame(dec, io)) {
return IDecError(idec, dec->status_);
}
return VP8_STATUS_OK;
}
// Remaining partitions
static VP8StatusCode DecodeRemaining(WebPIDecoder*
const idec) {
VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
VP8Io*
const io = &idec->io_;
// Make sure partition #0 has been read before, to set dec to ready_.
if (!dec->ready_) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) {
if (idec->last_mb_y_ != dec->mb_y_) {
if (!VP8ParseIntraModeRow(&dec->br_, dec)) {
// note: normally, error shouldn't occur since we already have the whole
// partition0 available here in DecodeRemaining(). Reaching EOF while
// reading intra modes really means a BITSTREAM_ERROR.
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
idec->last_mb_y_ = dec->mb_y_;
}
for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) {
VP8BitReader*
const token_br =
&dec->parts_[dec->mb_y_ & dec->num_parts_minus_one_];
MBContext context;
SaveContext(dec, token_br, &context);
if (!VP8DecodeMB(dec, token_br)) {
// We shouldn't fail when MAX_MB data was available
if (dec->num_parts_minus_one_ == 0 &&
MemDataSize(&idec->mem_) > MAX_MB_SIZE) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
// Synchronize the threads.
if (dec->mt_method_ > 0) {
if (!WebPGetWorkerInterface()->Sync(&dec->worker_)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
}
RestoreContext(&context, dec, token_br);
return VP8_STATUS_SUSPENDED;
}
// Release buffer only if there is only one partition
if (dec->num_parts_minus_one_ == 0) {
idec->mem_.start_ = token_br->buf_ - idec->mem_.buf_;
assert(idec->mem_.start_ <= idec->mem_.end_);
}
}
VP8InitScanline(dec);
// Prepare for next scanline
// Reconstruct, filter and emit the row.
if (!VP8ProcessRow(dec, io)) {
return IDecError(idec, VP8_STATUS_USER_ABORT);
}
}
// Synchronize the thread and check for errors.
if (!VP8ExitCritical(dec, io)) {
idec->state_ = STATE_ERROR;
// prevent re-entry in IDecError
return IDecError(idec, VP8_STATUS_USER_ABORT);
}
dec->ready_ = 0;
return FinishDecoding(idec);
}
static VP8StatusCode ErrorStatusLossless(WebPIDecoder*
const idec,
VP8StatusCode status) {
if (status == VP8_STATUS_SUSPENDED || status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_SUSPENDED;
}
return IDecError(idec, status);
}
static VP8StatusCode DecodeVP8LHeader(WebPIDecoder*
const idec) {
VP8Io*
const io = &idec->io_;
VP8LDecoder*
const dec = (VP8LDecoder*)idec->dec_;
const WebPDecParams*
const params = &idec->params_;
WebPDecBuffer*
const output = params->output;
size_t curr_size = MemDataSize(&idec->mem_);
assert(idec->is_lossless_);
// Wait until there's enough data for decoding header.
if (curr_size < (idec->chunk_size_ >> 3)) {
dec->status_ = VP8_STATUS_SUSPENDED;
return ErrorStatusLossless(idec, dec->status_);
}
if (!VP8LDecodeHeader(dec, io)) {
if (dec->status_ == VP8_STATUS_BITSTREAM_ERROR &&
curr_size < idec->chunk_size_) {
dec->status_ = VP8_STATUS_SUSPENDED;
}
return ErrorStatusLossless(idec, dec->status_);
}
// Allocate/verify output buffer now.
dec->status_ = WebPAllocateDecBuffer(io->width, io->height, params->options,
output);
if (dec->status_ != VP8_STATUS_OK) {
return IDecError(idec, dec->status_);
}
idec->state_ = STATE_VP8L_DATA;
return VP8_STATUS_OK;
}
static VP8StatusCode DecodeVP8LData(WebPIDecoder*
const idec) {
VP8LDecoder*
const dec = (VP8LDecoder*)idec->dec_;
const size_t curr_size = MemDataSize(&idec->mem_);
assert(idec->is_lossless_);
// Switch to incremental decoding if we don't have all the bytes available.
dec->incremental_ = (curr_size < idec->chunk_size_);
if (!VP8LDecodeImage(dec)) {
return ErrorStatusLossless(idec, dec->status_);
}
assert(dec->status_ == VP8_STATUS_OK || dec->status_ == VP8_STATUS_SUSPENDED);
return (dec->status_ == VP8_STATUS_SUSPENDED) ? dec->status_
: FinishDecoding(idec);
}
// Main decoding loop
static VP8StatusCode IDecode(WebPIDecoder* idec) {
VP8StatusCode status = VP8_STATUS_SUSPENDED;
if (idec->state_ == STATE_WEBP_HEADER) {
status = DecodeWebPHeaders(idec);
}
else {
if (idec->dec_ == NULL) {
return VP8_STATUS_SUSPENDED;
// can't continue if we have no decoder.
}
}
if (idec->state_ == STATE_VP8_HEADER) {
status = DecodeVP8FrameHeader(idec);
}
if (idec->state_ == STATE_VP8_PARTS0) {
status = DecodePartition0(idec);
}
if (idec->state_ == STATE_VP8_DATA) {
const VP8Decoder*
const dec = (VP8Decoder*)idec->dec_;
if (dec == NULL) {
return VP8_STATUS_SUSPENDED;
// can't continue if we have no decoder.
}
status = DecodeRemaining(idec);
}
if (idec->state_ == STATE_VP8L_HEADER) {
status = DecodeVP8LHeader(idec);
}
if (idec->state_ == STATE_VP8L_DATA) {
status = DecodeVP8LData(idec);
}
return status;
}
//------------------------------------------------------------------------------
// Internal constructor
WEBP_NODISCARD
static WebPIDecoder* NewDecoder(
WebPDecBuffer*
const output_buffer,
const WebPBitstreamFeatures*
const features) {
WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL,
sizeof(*idec));
if (idec == NULL) {
return NULL;
}
idec->state_ = STATE_WEBP_HEADER;
idec->chunk_size_ = 0;
idec->last_mb_y_ = -1;
InitMemBuffer(&idec->mem_);
if (!WebPInitDecBuffer(&idec->output_) || !VP8InitIo(&idec->io_)) {
WebPSafeFree(idec);
return NULL;
}
WebPResetDecParams(&idec->params_);
if (output_buffer == NULL || WebPAvoidSlowMemory(output_buffer, features)) {
idec->params_.output = &idec->output_;
idec->final_output_ = output_buffer;
if (output_buffer != NULL) {
idec->params_.output->colorspace = output_buffer->colorspace;
}
}
else {
idec->params_.output = output_buffer;
idec->final_output_ = NULL;
}
WebPInitCustomIo(&idec->params_, &idec->io_);
// Plug the I/O functions.
return idec;
}
//------------------------------------------------------------------------------
// Public functions
WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
return NewDecoder(output_buffer, NULL);
}
WebPIDecoder* WebPIDecode(
const uint8_t* data, size_t data_size,
WebPDecoderConfig* config) {
WebPIDecoder* idec;
WebPBitstreamFeatures tmp_features;
WebPBitstreamFeatures*
const features =
(config == NULL) ? &tmp_features : &config->input;
memset(&tmp_features, 0,
sizeof(tmp_features));
// Parse the bitstream's features, if requested:
if (data != NULL && data_size > 0) {
if (WebPGetFeatures(data, data_size, features) != VP8_STATUS_OK) {
return NULL;
}
}
// Create an instance of the incremental decoder
idec = (config != NULL) ? NewDecoder(&config->output, features)
: NewDecoder(NULL, features);
if (idec == NULL) {
return NULL;
}
// Finish initialization
if (config != NULL) {
idec->params_.options = &config->options;
}
return idec;
}
void WebPIDelete(WebPIDecoder* idec) {
if (idec == NULL)
return;
if (idec->dec_ != NULL) {
if (!idec->is_lossless_) {
if (idec->state_ == STATE_VP8_DATA) {
// Synchronize the thread, clean-up and check for errors.
// TODO(vrabaud) do we care about the return result?
(
void)VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
}
VP8Delete((VP8Decoder*)idec->dec_);
}
else {
VP8LDelete((VP8LDecoder*)idec->dec_);
}
}
ClearMemBuffer(&idec->mem_);
WebPFreeDecBuffer(&idec->output_);
WebPSafeFree(idec);
}
//------------------------------------------------------------------------------
// Wrapper toward WebPINewDecoder
WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE csp, uint8_t* output_buffer,
size_t output_buffer_size,
int output_stride) {
const int is_external_memory = (output_buffer != NULL) ? 1 : 0;
WebPIDecoder* idec;
if (csp >= MODE_YUV)
return NULL;
if (is_external_memory == 0) {
// Overwrite parameters to sane values.
output_buffer_size = 0;
output_stride = 0;
}
else {
// A buffer was passed. Validate the other params.
if (output_stride == 0 || output_buffer_size == 0) {
return NULL;
// invalid parameter.
}
}
idec = WebPINewDecoder(NULL);
if (idec == NULL)
return NULL;
idec->output_.colorspace = csp;
idec->output_.is_external_memory = is_external_memory;
idec->output_.u.RGBA.rgba = output_buffer;
idec->output_.u.RGBA.stride = output_stride;
idec->output_.u.RGBA.size = output_buffer_size;
return idec;
}
WebPIDecoder* WebPINewYUVA(uint8_t* luma, size_t luma_size,
int luma_stride,
uint8_t* u, size_t u_size,
int u_stride,
uint8_t* v, size_t v_size,
int v_stride,
uint8_t* a, size_t a_size,
int a_stride) {
const int is_external_memory = (luma != NULL) ? 1 : 0;
WebPIDecoder* idec;
WEBP_CSP_MODE colorspace;
if (is_external_memory == 0) {
// Overwrite parameters to sane values.
luma_size = u_size = v_size = a_size = 0;
luma_stride = u_stride = v_stride = a_stride = 0;
u = v = a = NULL;
colorspace = MODE_YUVA;
}
else {
// A luma buffer was passed. Validate the other parameters.
if (u == NULL || v == NULL)
return NULL;
if (luma_size == 0 || u_size == 0 || v_size == 0)
return NULL;
if (luma_stride == 0 || u_stride == 0 || v_stride == 0)
return NULL;
if (a != NULL) {
if (a_size == 0 || a_stride == 0)
return NULL;
}
colorspace = (a == NULL) ? MODE_YUV : MODE_YUVA;
}
idec = WebPINewDecoder(NULL);
if (idec == NULL)
return NULL;
idec->output_.colorspace = colorspace;
idec->output_.is_external_memory = is_external_memory;
idec->output_.u.YUVA.y = luma;
idec->output_.u.YUVA.y_stride = luma_stride;
idec->output_.u.YUVA.y_size = luma_size;
idec->output_.u.YUVA.u = u;
idec->output_.u.YUVA.u_stride = u_stride;
idec->output_.u.YUVA.u_size = u_size;
idec->output_.u.YUVA.v = v;
idec->output_.u.YUVA.v_stride = v_stride;
idec->output_.u.YUVA.v_size = v_size;
idec->output_.u.YUVA.a = a;
idec->output_.u.YUVA.a_stride = a_stride;
idec->output_.u.YUVA.a_size = a_size;
return idec;
}
WebPIDecoder* WebPINewYUV(uint8_t* luma, size_t luma_size,
int luma_stride,
uint8_t* u, size_t u_size,
int u_stride,
uint8_t* v, size_t v_size,
int v_stride) {
return WebPINewYUVA(luma, luma_size, luma_stride,
u, u_size, u_stride,
v, v_size, v_stride,
NULL, 0, 0);
}
//------------------------------------------------------------------------------
static VP8StatusCode IDecCheckStatus(
const WebPIDecoder*
const idec) {
assert(idec);
if (idec->state_ == STATE_ERROR) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (idec->state_ == STATE_DONE) {
return VP8_STATUS_OK;
}
return VP8_STATUS_SUSPENDED;
}
VP8StatusCode WebPIAppend(WebPIDecoder* idec,
const uint8_t* data, size_t data_size) {
VP8StatusCode status;
if (idec == NULL || data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
status = IDecCheckStatus(idec);
if (status != VP8_STATUS_SUSPENDED) {
return status;
}
// Check mixed calls between RemapMemBuffer and AppendToMemBuffer.
if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_APPEND)) {
return VP8_STATUS_INVALID_PARAM;
}
// Append data to memory buffer
if (!AppendToMemBuffer(idec, data, data_size)) {
return VP8_STATUS_OUT_OF_MEMORY;
}
return IDecode(idec);
}
VP8StatusCode WebPIUpdate(WebPIDecoder* idec,
const uint8_t* data, size_t data_size) {
VP8StatusCode status;
if (idec == NULL || data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
status = IDecCheckStatus(idec);
if (status != VP8_STATUS_SUSPENDED) {
return status;
}
// Check mixed calls between RemapMemBuffer and AppendToMemBuffer.
if (!CheckMemBufferMode(&idec->mem_, MEM_MODE_MAP)) {
return VP8_STATUS_INVALID_PARAM;
}
// Make the memory buffer point to the new buffer
if (!RemapMemBuffer(idec, data, data_size)) {
return VP8_STATUS_INVALID_PARAM;
}
return IDecode(idec);
}
//------------------------------------------------------------------------------
static const WebPDecBuffer* GetOutputBuffer(
const WebPIDecoder*
const idec) {
if (idec == NULL || idec->dec_ == NULL) {
return NULL;
}
if (idec->state_ <= STATE_VP8_PARTS0) {
return NULL;
}
if (idec->final_output_ != NULL) {
return NULL;
// not yet slow-copied
}
return idec->params_.output;
}
const WebPDecBuffer* WebPIDecodedArea(
const WebPIDecoder* idec,
int* left,
int* top,
int* width,
int* height) {
const WebPDecBuffer*
const src = GetOutputBuffer(idec);
if (left != NULL) *left = 0;
if (top != NULL) *top = 0;
if (src != NULL) {
if (width != NULL) *width = src->width;
if (height != NULL) *height = idec->params_.last_y;
}
else {
if (width != NULL) *width = 0;
if (height != NULL) *height = 0;
}
return src;
}
WEBP_NODISCARD uint8_t* WebPIDecGetRGB(
const WebPIDecoder* idec,
int* last_y,
int* width,
int* height,
int* stride) {
const WebPDecBuffer*
const src = GetOutputBuffer(idec);
if (src == NULL)
return NULL;
if (src->colorspace >= MODE_YUV) {
return NULL;
}
if (last_y != NULL) *last_y = idec->params_.last_y;
if (width != NULL) *width = src->width;
if (height != NULL) *height = src->height;
if (stride != NULL) *stride = src->u.RGBA.stride;
return src->u.RGBA.rgba;
}
WEBP_NODISCARD uint8_t* WebPIDecGetYUVA(
const WebPIDecoder* idec,
int* last_y,
uint8_t** u, uint8_t** v, uint8_t** a,
int* width,
int* height,
int* stride,
int* uv_stride,
int* a_stride) {
const WebPDecBuffer*
const src = GetOutputBuffer(idec);
if (src == NULL)
return NULL;
if (src->colorspace < MODE_YUV) {
return NULL;
}
if (last_y != NULL) *last_y = idec->params_.last_y;
if (u != NULL) *u = src->u.YUVA.u;
if (v != NULL) *v = src->u.YUVA.v;
if (a != NULL) *a = src->u.YUVA.a;
if (width != NULL) *width = src->width;
if (height != NULL) *height = src->height;
if (stride != NULL) *stride = src->u.YUVA.y_stride;
if (uv_stride != NULL) *uv_stride = src->u.YUVA.u_stride;
if (a_stride != NULL) *a_stride = src->u.YUVA.a_stride;
return src->u.YUVA.y;
}
int WebPISetIOHooks(WebPIDecoder*
const idec,
VP8IoPutHook put,
VP8IoSetupHook setup,
VP8IoTeardownHook teardown,
void* user_data) {
if (idec == NULL || idec->state_ > STATE_WEBP_HEADER) {
return 0;
}
idec->io_.put = put;
idec->io_.setup = setup;
idec->io_.teardown = teardown;
idec->io_.opaque = user_data;
return 1;
}
