// Assemble a single image WebP bitstream from 'wpi'.
static WebPMuxError SynthesizeBitstream(const WebPMuxImage* const wpi,
WebPData* const bitstream) {
uint8_t* dst;
// Allocate data.
const int need_vp8x = (wpi->alpha_ != NULL);
const size_t vp8x_size = need_vp8x ? CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE : 0;
const size_t alpha_size = need_vp8x ? ChunkDiskSize(wpi->alpha_) : 0;
// Note: No need to output ANMF/FRGM chunk for a single image.
const size_t size = RIFF_HEADER_SIZE + vp8x_size + alpha_size +
ChunkDiskSize(wpi->img_);
uint8_t* const data = (uint8_t*)WebPSafeMalloc(1ULL, size);
if (data == NULL) return WEBP_MUX_MEMORY_ERROR;
// Main RIFF header.
dst = MuxEmitRiffHeader(data, size);
if (need_vp8x) {
dst = EmitVP8XChunk(dst, wpi->width_, wpi->height_, ALPHA_FLAG); // VP8X.
dst = ChunkListEmit(wpi->alpha_, dst); // ALPH.
}
// Bitstream.
dst = ChunkListEmit(wpi->img_, dst);
assert(dst == data + size);
// Output.
bitstream->bytes = data;
bitstream->size = size;
return WEBP_MUX_OK;
}
uint8_t* MuxImageEmit(const WebPMuxImage* const wpi, uint8_t* dst) {
// Ordering of chunks to be emitted is strictly as follows:
// 1. ANMF/FRGM chunk (if present).
// 2. ALPH chunk (if present).
// 3. VP8/VP8L chunk.
assert(wpi);
if (wpi->header_ != NULL) {
dst = ChunkEmitSpecial(wpi->header_, MuxImageDiskSize(wpi), dst);
}
if (wpi->alpha_ != NULL) dst = ChunkEmit(wpi->alpha_, dst);
if (wpi->img_ != NULL) dst = ChunkEmit(wpi->img_, dst);
if (wpi->unknown_ != NULL) dst = ChunkListEmit(wpi->unknown_, dst);
return dst;
}
WebPMuxError WebPMuxAssemble(WebPMux* mux, WebPData* assembled_data) {
size_t size = 0;
uint8_t* data = NULL;
uint8_t* dst = NULL;
WebPMuxError err;
if (assembled_data == NULL) {
return WEBP_MUX_INVALID_ARGUMENT;
}
// Clean up returned data, in case something goes wrong.
memset(assembled_data, 0, sizeof(*assembled_data));
if (mux == NULL) {
return WEBP_MUX_INVALID_ARGUMENT;
}
// Finalize mux.
err = MuxCleanup(mux);
if (err != WEBP_MUX_OK) return err;
err = CreateVP8XChunk(mux);
if (err != WEBP_MUX_OK) return err;
// Allocate data.
size = ChunkListDiskSize(mux->vp8x_) + ChunkListDiskSize(mux->iccp_)
+ ChunkListDiskSize(mux->anim_) + ImageListDiskSize(mux->images_)
+ ChunkListDiskSize(mux->exif_) + ChunkListDiskSize(mux->xmp_)
+ ChunkListDiskSize(mux->unknown_) + RIFF_HEADER_SIZE;
data = (uint8_t*)WebPSafeMalloc(1ULL, size);
if (data == NULL) return WEBP_MUX_MEMORY_ERROR;
// Emit header & chunks.
dst = MuxEmitRiffHeader(data, size);
dst = ChunkListEmit(mux->vp8x_, dst);
dst = ChunkListEmit(mux->iccp_, dst);
dst = ChunkListEmit(mux->anim_, dst);
dst = ImageListEmit(mux->images_, dst);
dst = ChunkListEmit(mux->exif_, dst);
dst = ChunkListEmit(mux->xmp_, dst);
dst = ChunkListEmit(mux->unknown_, dst);
assert(dst == data + size);
// Validate mux.
err = MuxValidate(mux);
if (err != WEBP_MUX_OK) {
WebPSafeFree(data);
data = NULL;
size = 0;
}
// Finalize data.
assembled_data->bytes = data;
assembled_data->size = size;
return err;
}
WebPMuxError WebPMuxAssemble(WebPMux* mux, WebPData* assembled_data) {
size_t size = 0;
uint8_t* data = NULL;
uint8_t* dst = NULL;
int num_frames;
int num_loop_chunks;
WebPMuxError err;
if (mux == NULL || assembled_data == NULL) {
return WEBP_MUX_INVALID_ARGUMENT;
}
// Remove LOOP chunk if unnecessary.
err = WebPMuxNumChunks(mux, kChunks[IDX_LOOP].id, &num_loop_chunks);
if (err != WEBP_MUX_OK) return err;
if (num_loop_chunks >= 1) {
err = WebPMuxNumChunks(mux, kChunks[IDX_FRAME].id, &num_frames);
if (err != WEBP_MUX_OK) return err;
if (num_frames == 0) {
err = DeleteLoopCount(mux);
if (err != WEBP_MUX_OK) return err;
}
}
// Create VP8X chunk.
err = CreateVP8XChunk(mux);
if (err != WEBP_MUX_OK) return err;
// Allocate data.
size = ChunksListDiskSize(mux->vp8x_) + ChunksListDiskSize(mux->iccp_)
+ ChunksListDiskSize(mux->loop_) + MuxImageListDiskSize(mux->images_)
+ ChunksListDiskSize(mux->meta_) + ChunksListDiskSize(mux->unknown_)
+ RIFF_HEADER_SIZE;
data = (uint8_t*)malloc(size);
if (data == NULL) return WEBP_MUX_MEMORY_ERROR;
// Emit header & chunks.
dst = MuxEmitRiffHeader(data, size);
dst = ChunkListEmit(mux->vp8x_, dst);
dst = ChunkListEmit(mux->iccp_, dst);
dst = ChunkListEmit(mux->loop_, dst);
dst = MuxImageListEmit(mux->images_, dst);
dst = ChunkListEmit(mux->meta_, dst);
dst = ChunkListEmit(mux->unknown_, dst);
assert(dst == data + size);
// Validate mux.
err = MuxValidate(mux);
if (err != WEBP_MUX_OK) {
free(data);
data = NULL;
size = 0;
}
// Finalize.
assembled_data->bytes_ = data;
assembled_data->size_ = size;
return err;
}