static byte* ChunkEmit(WebPChunk* chunk, byte* dst)
{
assert(chunk);
assert(chunk.tag_ != NIL_TAG);
PutLE32(dst + 0, chunk.tag_);
PutLE32(dst + TAG_SIZE, chunk.payload_size_);
memcpy(dst + CHUNK_HEADER_SIZE, chunk.data_, chunk.payload_size_);
if (chunk.payload_size_ & 1)
dst[CHUNK_HEADER_SIZE + chunk.payload_size_] = 0; // Add padding.
return dst + ChunkDiskSize(chunk);
}
// Outputs a pointer to 'prev_chunk.next_',
// where 'prev_chunk' is the pointer to the chunk at position (nth - 1).
// Returns 1 if nth chunk was found, 0 otherwise.
static int ChunkSearchListToSet(WebPChunk** chunk_list, uint nth,
WebPChunk*** location)
{
uint count = 0;
assert(chunk_list);
*location = chunk_list;
while (*chunk_list) {
WebPChunk* cur_chunk = *chunk_list;
++count;
if (count == nth) return 1; // Found.
chunk_list = &cur_chunk.next_;
*location = chunk_list;
}
// *chunk_list is ok to be null if adding at last location.
return (nth == 0 || (count == nth - 1)) ? 1 : 0;
}
// Fill the chunk with the given data, after verifying that the data size
// doesn't exceed 'max_size'.
static WebPMuxError ChunkAssignData(WebPChunk* chunk, byte* data,
uint data_size, uint riff_size,
int copy_data) {
uint chunk_size;
// Sanity checks.
if (data_size < TAG_SIZE) return WEBP_MUX_NOT_ENOUGH_DATA;
chunk_size = GetLE32(data + TAG_SIZE);
{
uint chunk_disk_size = SizeWithPadding(chunk_size);
if (chunk_disk_size > riff_size) return WEBP_MUX_BAD_DATA;
if (chunk_disk_size > data_size) return WEBP_MUX_NOT_ENOUGH_DATA;
}
// Data assignment.
return ChunkAssignDataImageInfo(chunk, data + CHUNK_HEADER_SIZE, chunk_size,
null, copy_data, GetLE32(data + 0));
}
// Count number of chunks matching 'tag' in the 'chunk_list'.
// If tag == NIL_TAG, any tag will be matched.
static int CountChunks(WebPChunk* chunk_list, uint tag) {
int count = 0;
WebPChunk* current;
for (current = chunk_list; current != null; current = current.next_) {
if (tag == NIL_TAG || current.tag_ == tag) {
count++; // Count chunks whose tags match.
}
}
return count;
}
static void DeleteAllChunks(WebPChunk* chunk_list) {
while (*chunk_list) {
*chunk_list = ChunkDelete(*chunk_list);
}
}
static WebPMuxError DeleteChunks(WebPChunk** chunk_list, uint tag) {
WebPMuxError err = WEBP_MUX_NOT_FOUND;
assert(chunk_list);
while (*chunk_list) {
WebPChunk* chunk = *chunk_list;
if (chunk.tag_ == tag) {
*chunk_list = ChunkDelete(chunk);
err = WEBP_MUX_OK;
} else {
chunk_list = &chunk.next_;
}
}
return err;
}
//------------------------------------------------------------------------------
// Chunk search methods.
// Returns next chunk in the chunk list with the given tag.
static WebPChunk ChunkSearchNextInList(WebPChunk chunk, uint tag)
{
while (chunk && chunk.tag_ != tag) {
chunk = chunk.next_;
}
return chunk;
}
/// <summary>
/// Life of a chunk object.
/// </summary>
static WebPChunk ChunkRelease(WebPChunk chunk)
{
WebPChunk next;
if (chunk == null) return null;
free(chunk.image_info_);
if (chunk.owner_)
{
free((void*)chunk.data_);
}
next = chunk.next_;
ChunkInit(chunk);
return next;
}
//------------------------------------------------------------------------------
// Chunk serialization methods.
uint ChunksListDiskSize(WebPChunk* chunk_list)
{
uint size = 0;
while (chunk_list) {
size += ChunkDiskSize(chunk_list);
chunk_list = chunk_list.next_;
}
return size;
}
WebPMuxError ChunkSetNth(WebPChunk* chunk, WebPChunk** chunk_list, uint nth)
{
WebPChunk* new_chunk;
if (!ChunkSearchListToSet(chunk_list, nth, &chunk_list)) {
return WEBP_MUX_NOT_FOUND;
}
new_chunk = (WebPChunk*)malloc(sizeof(*new_chunk));
if (new_chunk == null) return WEBP_MUX_MEMORY_ERROR;
*new_chunk = *chunk;
new_chunk.next_ = *chunk_list;
*chunk_list = new_chunk;
return WEBP_MUX_OK;
}
WebPChunk ChunkSearchList(WebPChunk first, uint nth, uint tag)
{
uint iter = nth;
first = ChunkSearchNextInList(first, tag);
if (!first) return null;
while (--iter != 0) {
WebPChunk next_chunk = ChunkSearchNextInList(first.next_, tag);
if (next_chunk == null) break;
first = next_chunk;
}
return ((nth > 0) && (iter > 0)) ? null : first;
}
byte* ChunkListEmit(WebPChunk* chunk_list, byte* dst)
{
while (chunk_list) {
dst = ChunkEmit(chunk_list, dst);
chunk_list = chunk_list.next_;
}
return dst;
}
//------------------------------------------------------------------------------
// Chunk deletion method(s).
WebPChunk* ChunkDelete(WebPChunk* chunk)
{
WebPChunk* next = ChunkRelease(chunk);
free(chunk);
return next;
}
//------------------------------------------------------------------------------
// Chunk writer methods.
WebPMuxError ChunkAssignDataImageInfo(WebPChunk* chunk, byte* data, uint data_size, WebPImageInfo* image_info, int copy_data, uint tag)
{
// For internally allocated chunks, always copy data & make it owner of data.
if ((tag == kChunks[VP8X_ID].chunkTag) ||
(tag == kChunks[LOOP_ID].chunkTag)) {
copy_data = 1;
}
ChunkRelease(chunk);
if (data == null) {
data_size = 0;
} else if (data_size == 0) {
data = null;
}
if (data != null) {
if (copy_data) {
// Copy data.
chunk.data_ = (byte*)malloc(data_size);
if (chunk.data_ == null) return WEBP_MUX_MEMORY_ERROR;
memcpy((byte*)chunk.data_, data, data_size);
chunk.payload_size_ = data_size;
// Chunk is owner of data.
chunk.owner_ = 1;
} else {
// Don't copy data.
chunk.data_ = data;
chunk.payload_size_ = data_size;
}
}
if (tag == kChunks[IMAGE_ID].chunkTag) {
chunk.image_info_ = image_info;
}
chunk.tag_ = tag;
return WEBP_MUX_OK;
}