WebPMuxError WebPMuxGetChunk(const WebPMux* mux, const char fourcc[4],
WebPData* chunk_data) {
CHUNK_INDEX idx;
if (mux == NULL || fourcc == NULL || chunk_data == NULL) {
return WEBP_MUX_INVALID_ARGUMENT;
}
idx = ChunkGetIndexFromFourCC(fourcc);
if (IsWPI(kChunks[idx].id)) { // An image chunk.
return WEBP_MUX_INVALID_ARGUMENT;
} else if (idx != IDX_UNKNOWN) { // A known chunk type.
return MuxGet(mux, idx, 1, chunk_data);
} else { // An unknown chunk type.
const WebPChunk* const chunk =
ChunkSearchList(mux->unknown_, 1, ChunkGetTagFromFourCC(fourcc));
if (chunk == NULL) return WEBP_MUX_NOT_FOUND;
*chunk_data = chunk->data_;
return WEBP_MUX_OK;
}
}
WebPMuxError WebPMuxSetChunk(WebPMux* mux, const char fourcc[4],
const WebPData* chunk_data, int copy_data) {
CHUNK_INDEX idx;
uint32_t tag;
WebPMuxError err;
if (mux == NULL || fourcc == NULL || chunk_data == NULL ||
chunk_data->bytes == NULL || chunk_data->size > MAX_CHUNK_PAYLOAD) {
return WEBP_MUX_INVALID_ARGUMENT;
}
idx = ChunkGetIndexFromFourCC(fourcc);
tag = ChunkGetTagFromFourCC(fourcc);
// Delete existing chunk(s) with the same 'fourcc'.
err = MuxDeleteAllNamedData(mux, tag);
if (err != WEBP_MUX_OK && err != WEBP_MUX_NOT_FOUND) return err;
// Add the given chunk.
return MuxSet(mux, idx, 1, chunk_data, copy_data);
}