godot/drivers/webpold/dec/idec.c

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// Copyright 2011 Google Inc. All Rights Reserved.
//
// This code is licensed under the same terms as WebM:
// Software License Agreement: http://www.webmproject.org/license/software/
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// Incremental decoding
//
// Author: somnath@google.com (Somnath Banerjee)
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include "./webpi.h"
#include "./vp8i.h"
#include "../utils/utils.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
// 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 like HEADER->PARTS0->DATA->DONE.
// If there is any error the decoder goes into state ERROR.
typedef enum {
STATE_PRE_VP8, // All data before that of the first VP8 chunk.
STATE_VP8_FRAME_HEADER, // For VP8 Frame header (within 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)
size_t chunk_size_; // Compressed VP8/VP8L size extracted from Header.
};
// MB context to restore in case VP8DecodeMB() fails
typedef struct {
VP8MB left_;
VP8MB info_;
uint8_t intra_t_[4];
uint8_t intra_l_[4];
VP8BitReader br_;
VP8BitReader token_br_;
} MBContext;
//------------------------------------------------------------------------------
// MemBuffer: incoming data handling
static void RemapBitReader(VP8BitReader* const br, ptrdiff_t offset) {
if (br->buf_ != NULL) {
br->buf_ += offset;
br->buf_end_ += offset;
}
}
static WEBP_INLINE size_t MemDataSize(const MemBuffer* mem) {
return (mem->end_ - mem->start_);
}
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 int last_part = dec->num_parts_ - 1;
if (offset != 0) {
int p;
for (p = 0; p <= last_part; ++p) {
RemapBitReader(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) {
RemapBitReader(&dec->br_, offset);
}
}
assert(last_part >= 0);
dec->parts_[last_part].buf_end_ = mem->buf_ + mem->end_;
} 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.
static int AppendToMemBuffer(WebPIDecoder* const idec,
const uint8_t* const data, size_t data_size) {
MemBuffer* const mem = &idec->mem_;
const uint8_t* const old_base = mem->buf_ + mem->start_;
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 current_size = MemDataSize(mem);
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;
memcpy(new_buf, old_base, current_size);
free(mem->buf_);
mem->buf_ = new_buf;
mem->buf_size_ = (size_t)extra_size;
mem->start_ = 0;
mem->end_ = current_size;
}
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_base);
return 1;
}
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_base = mem->buf_ + mem->start_;
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_base);
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) {
free(mem->buf_);
free((void*)mem->part0_buf_);
}
}
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;
}
//------------------------------------------------------------------------------
// Macroblock-decoding contexts
static void SaveContext(const VP8Decoder* dec, const VP8BitReader* token_br,
MBContext* const context) {
const VP8BitReader* const br = &dec->br_;
const VP8MB* const left = dec->mb_info_ - 1;
const VP8MB* const info = dec->mb_info_ + dec->mb_x_;
context->left_ = *left;
context->info_ = *info;
context->br_ = *br;
context->token_br_ = *token_br;
memcpy(context->intra_t_, dec->intra_t_ + 4 * dec->mb_x_, 4);
memcpy(context->intra_l_, dec->intra_l_, 4);
}
static void RestoreContext(const MBContext* context, VP8Decoder* const dec,
VP8BitReader* const token_br) {
VP8BitReader* const br = &dec->br_;
VP8MB* const left = dec->mb_info_ - 1;
VP8MB* const info = dec->mb_info_ + dec->mb_x_;
*left = context->left_;
*info = context->info_;
*br = context->br_;
*token_br = context->token_br_;
memcpy(dec->intra_t_ + 4 * dec->mb_x_, context->intra_t_, 4);
memcpy(dec->intra_l_, context->intra_l_, 4);
}
//------------------------------------------------------------------------------
static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) {
if (idec->state_ == STATE_VP8_DATA) {
VP8Io* const io = &idec->io_;
if (io->teardown) {
io->teardown(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;
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;
}
idec->dec_ = dec;
#ifdef WEBP_USE_THREAD
dec->use_threads_ = (idec->params_.options != NULL) &&
(idec->params_.options->use_threads > 0);
#else
dec->use_threads_ = 0;
#endif
dec->alpha_data_ = headers.alpha_data;
dec->alpha_data_size_ = headers.alpha_data_size;
ChangeState(idec, STATE_VP8_FRAME_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_);
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_, NULL, NULL)) {
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 int CopyParts0Data(WebPIDecoder* const idec) {
VP8Decoder* const dec = (VP8Decoder*)idec->dec_;
VP8BitReader* const br = &dec->br_;
const size_t psize = br->buf_end_ - br->buf_;
MemBuffer* const mem = &idec->mem_;
assert(!idec->is_lossless_);
assert(mem->part0_buf_ == NULL);
assert(psize > 0);
assert(psize <= mem->part0_size_); // Format limit: no need for runtime check
if (mem->mode_ == MEM_MODE_APPEND) {
// We copy and grab ownership of the partition #0 data.
uint8_t* const part0_buf = (uint8_t*)malloc(psize);
if (part0_buf == NULL) {
return 0;
}
memcpy(part0_buf, br->buf_, psize);
mem->part0_buf_ = part0_buf;
br->buf_ = part0_buf;
br->buf_end_ = part0_buf + psize;
} else {
// Else: just keep pointers to the partition #0's data in dec_->br_.
}
mem->start_ += psize;
return 1;
}
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_);
}
if (!CopyParts0Data(idec)) {
return IDecError(idec, VP8_STATUS_OUT_OF_MEMORY);
}
// 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_;
assert(dec->ready_);
for (; dec->mb_y_ < dec->mb_h_; ++dec->mb_y_) {
VP8BitReader* token_br = &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
if (dec->mb_x_ == 0) {
VP8InitScanline(dec);
}
for (; dec->mb_x_ < dec->mb_w_; dec->mb_x_++) {
MBContext context;
SaveContext(dec, token_br, &context);
if (!VP8DecodeMB(dec, token_br)) {
RestoreContext(&context, dec, token_br);
// We shouldn't fail when MAX_MB data was available
if (dec->num_parts_ == 1 && MemDataSize(&idec->mem_) > MAX_MB_SIZE) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
return VP8_STATUS_SUSPENDED;
}
VP8ReconstructBlock(dec);
// Store data and save block's filtering params
VP8StoreBlock(dec);
// Release buffer only if there is only one partition
if (dec->num_parts_ == 1) {
idec->mem_.start_ = token_br->buf_ - idec->mem_.buf_;
assert(idec->mem_.start_ <= idec->mem_.end_);
}
}
if (!VP8ProcessRow(dec, io)) {
return IDecError(idec, VP8_STATUS_USER_ABORT);
}
dec->mb_x_ = 0;
}
// Synchronize the thread and check for errors.
if (!VP8ExitCritical(dec, io)) {
return IDecError(idec, VP8_STATUS_USER_ABORT);
}
dec->ready_ = 0;
idec->state_ = STATE_DONE;
return VP8_STATUS_OK;
}
static int 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)) {
return VP8_STATUS_SUSPENDED;
}
if (!VP8LDecodeHeader(dec, io)) {
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_);
// At present Lossless decoder can't decode image incrementally. So wait till
// all the image data is aggregated before image can be decoded.
if (curr_size < idec->chunk_size_) {
return VP8_STATUS_SUSPENDED;
}
if (!VP8LDecodeImage(dec)) {
return ErrorStatusLossless(idec, dec->status_);
}
idec->state_ = STATE_DONE;
return VP8_STATUS_OK;
}
// Main decoding loop
static VP8StatusCode IDecode(WebPIDecoder* idec) {
VP8StatusCode status = VP8_STATUS_SUSPENDED;
if (idec->state_ == STATE_PRE_VP8) {
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_FRAME_HEADER) {
status = DecodeVP8FrameHeader(idec);
}
if (idec->state_ == STATE_VP8_PARTS0) {
status = DecodePartition0(idec);
}
if (idec->state_ == STATE_VP8_DATA) {
status = DecodeRemaining(idec);
}
if (idec->state_ == STATE_VP8L_HEADER) {
status = DecodeVP8LHeader(idec);
}
if (idec->state_ == STATE_VP8L_DATA) {
status = DecodeVP8LData(idec);
}
return status;
}
//------------------------------------------------------------------------------
// Public functions
WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
WebPIDecoder* idec = (WebPIDecoder*)calloc(1, sizeof(*idec));
if (idec == NULL) {
return NULL;
}
idec->state_ = STATE_PRE_VP8;
idec->chunk_size_ = 0;
InitMemBuffer(&idec->mem_);
WebPInitDecBuffer(&idec->output_);
VP8InitIo(&idec->io_);
WebPResetDecParams(&idec->params_);
idec->params_.output = output_buffer ? output_buffer : &idec->output_;
WebPInitCustomIo(&idec->params_, &idec->io_); // Plug the I/O functions.
return idec;
}
WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size,
WebPDecoderConfig* config) {
WebPIDecoder* idec;
// Parse the bitstream's features, if requested:
if (data != NULL && data_size > 0 && config != NULL) {
if (WebPGetFeatures(data, data_size, &config->input) != VP8_STATUS_OK) {
return NULL;
}
}
// Create an instance of the incremental decoder
idec = WebPINewDecoder(config ? &config->output : NULL);
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_) {
VP8Delete(idec->dec_);
} else {
VP8LDelete(idec->dec_);
}
}
ClearMemBuffer(&idec->mem_);
WebPFreeDecBuffer(&idec->output_);
free(idec);
}
//------------------------------------------------------------------------------
// Wrapper toward WebPINewDecoder
WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE mode, uint8_t* output_buffer,
size_t output_buffer_size, int output_stride) {
WebPIDecoder* idec;
if (mode >= MODE_YUV) return NULL;
idec = WebPINewDecoder(NULL);
if (idec == NULL) return NULL;
idec->output_.colorspace = mode;
idec->output_.is_external_memory = 1;
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) {
WebPIDecoder* const idec = WebPINewDecoder(NULL);
if (idec == NULL) return NULL;
idec->output_.colorspace = (a == NULL) ? MODE_YUV : MODE_YUVA;
idec->output_.is_external_memory = 1;
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;
}
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;
// TODO(skal): later include handling of rotations.
if (src) {
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;
}
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;
}
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_PRE_VP8) {
return 0;
}
idec->io_.put = put;
idec->io_.setup = setup;
idec->io_.teardown = teardown;
idec->io_.opaque = user_data;
return 1;
}
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif