mirror of https://github.com/opencv/opencv.git
Open Source Computer Vision Library
https://opencv.org/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
558 lines
19 KiB
558 lines
19 KiB
// 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. |
|
// ----------------------------------------------------------------------------- |
|
// |
|
// Read APIs for mux. |
|
// |
|
// Authors: Urvang (urvang@google.com) |
|
// Vikas (vikasa@google.com) |
|
|
|
#include <assert.h> |
|
#include "src/mux/muxi.h" |
|
#include "src/utils/utils.h" |
|
|
|
//------------------------------------------------------------------------------ |
|
// Helper method(s). |
|
|
|
// Handy MACRO. |
|
#define SWITCH_ID_LIST(INDEX, LIST) \ |
|
if (idx == (INDEX)) { \ |
|
const WebPChunk* const chunk = ChunkSearchList((LIST), nth, \ |
|
kChunks[(INDEX)].tag); \ |
|
if (chunk) { \ |
|
*data = chunk->data_; \ |
|
return WEBP_MUX_OK; \ |
|
} else { \ |
|
return WEBP_MUX_NOT_FOUND; \ |
|
} \ |
|
} |
|
|
|
static WebPMuxError MuxGet(const WebPMux* const mux, CHUNK_INDEX idx, |
|
uint32_t nth, WebPData* const data) { |
|
assert(mux != NULL); |
|
assert(!IsWPI(kChunks[idx].id)); |
|
WebPDataInit(data); |
|
|
|
SWITCH_ID_LIST(IDX_VP8X, mux->vp8x_); |
|
SWITCH_ID_LIST(IDX_ICCP, mux->iccp_); |
|
SWITCH_ID_LIST(IDX_ANIM, mux->anim_); |
|
SWITCH_ID_LIST(IDX_EXIF, mux->exif_); |
|
SWITCH_ID_LIST(IDX_XMP, mux->xmp_); |
|
assert(idx != IDX_UNKNOWN); |
|
return WEBP_MUX_NOT_FOUND; |
|
} |
|
#undef SWITCH_ID_LIST |
|
|
|
// Fill the chunk with the given data (includes chunk header bytes), after some |
|
// verifications. |
|
static WebPMuxError ChunkVerifyAndAssign(WebPChunk* chunk, |
|
const uint8_t* data, size_t data_size, |
|
size_t riff_size, int copy_data) { |
|
uint32_t chunk_size; |
|
WebPData chunk_data; |
|
|
|
// Sanity checks. |
|
if (data_size < CHUNK_HEADER_SIZE) return WEBP_MUX_NOT_ENOUGH_DATA; |
|
chunk_size = GetLE32(data + TAG_SIZE); |
|
if (chunk_size > MAX_CHUNK_PAYLOAD) return WEBP_MUX_BAD_DATA; |
|
|
|
{ |
|
const size_t 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. |
|
chunk_data.bytes = data + CHUNK_HEADER_SIZE; |
|
chunk_data.size = chunk_size; |
|
return ChunkAssignData(chunk, &chunk_data, copy_data, GetLE32(data + 0)); |
|
} |
|
|
|
int MuxImageFinalize(WebPMuxImage* const wpi) { |
|
const WebPChunk* const img = wpi->img_; |
|
const WebPData* const image = &img->data_; |
|
const int is_lossless = (img->tag_ == kChunks[IDX_VP8L].tag); |
|
int w, h; |
|
int vp8l_has_alpha = 0; |
|
const int ok = is_lossless ? |
|
VP8LGetInfo(image->bytes, image->size, &w, &h, &vp8l_has_alpha) : |
|
VP8GetInfo(image->bytes, image->size, image->size, &w, &h); |
|
assert(img != NULL); |
|
if (ok) { |
|
// Ignore ALPH chunk accompanying VP8L. |
|
if (is_lossless && (wpi->alpha_ != NULL)) { |
|
ChunkDelete(wpi->alpha_); |
|
wpi->alpha_ = NULL; |
|
} |
|
wpi->width_ = w; |
|
wpi->height_ = h; |
|
wpi->has_alpha_ = vp8l_has_alpha || (wpi->alpha_ != NULL); |
|
} |
|
return ok; |
|
} |
|
|
|
static int MuxImageParse(const WebPChunk* const chunk, int copy_data, |
|
WebPMuxImage* const wpi) { |
|
const uint8_t* bytes = chunk->data_.bytes; |
|
size_t size = chunk->data_.size; |
|
const uint8_t* const last = (bytes == NULL) ? NULL : bytes + size; |
|
WebPChunk subchunk; |
|
size_t subchunk_size; |
|
WebPChunk** unknown_chunk_list = &wpi->unknown_; |
|
ChunkInit(&subchunk); |
|
|
|
assert(chunk->tag_ == kChunks[IDX_ANMF].tag); |
|
assert(!wpi->is_partial_); |
|
|
|
// ANMF. |
|
{ |
|
const size_t hdr_size = ANMF_CHUNK_SIZE; |
|
const WebPData temp = { bytes, hdr_size }; |
|
// Each of ANMF chunk contain a header at the beginning. So, its size should |
|
// be at least 'hdr_size'. |
|
if (size < hdr_size) goto Fail; |
|
ChunkAssignData(&subchunk, &temp, copy_data, chunk->tag_); |
|
} |
|
ChunkSetHead(&subchunk, &wpi->header_); |
|
wpi->is_partial_ = 1; // Waiting for ALPH and/or VP8/VP8L chunks. |
|
|
|
// Rest of the chunks. |
|
subchunk_size = ChunkDiskSize(&subchunk) - CHUNK_HEADER_SIZE; |
|
bytes += subchunk_size; |
|
size -= subchunk_size; |
|
|
|
while (bytes != last) { |
|
ChunkInit(&subchunk); |
|
if (ChunkVerifyAndAssign(&subchunk, bytes, size, size, |
|
copy_data) != WEBP_MUX_OK) { |
|
goto Fail; |
|
} |
|
switch (ChunkGetIdFromTag(subchunk.tag_)) { |
|
case WEBP_CHUNK_ALPHA: |
|
if (wpi->alpha_ != NULL) goto Fail; // Consecutive ALPH chunks. |
|
if (ChunkSetHead(&subchunk, &wpi->alpha_) != WEBP_MUX_OK) goto Fail; |
|
wpi->is_partial_ = 1; // Waiting for a VP8 chunk. |
|
break; |
|
case WEBP_CHUNK_IMAGE: |
|
if (wpi->img_ != NULL) goto Fail; // Only 1 image chunk allowed. |
|
if (ChunkSetHead(&subchunk, &wpi->img_) != WEBP_MUX_OK) goto Fail; |
|
if (!MuxImageFinalize(wpi)) goto Fail; |
|
wpi->is_partial_ = 0; // wpi is completely filled. |
|
break; |
|
case WEBP_CHUNK_UNKNOWN: |
|
if (wpi->is_partial_) { |
|
goto Fail; // Encountered an unknown chunk |
|
// before some image chunks. |
|
} |
|
if (ChunkAppend(&subchunk, &unknown_chunk_list) != WEBP_MUX_OK) { |
|
goto Fail; |
|
} |
|
break; |
|
default: |
|
goto Fail; |
|
break; |
|
} |
|
subchunk_size = ChunkDiskSize(&subchunk); |
|
bytes += subchunk_size; |
|
size -= subchunk_size; |
|
} |
|
if (wpi->is_partial_) goto Fail; |
|
return 1; |
|
|
|
Fail: |
|
ChunkRelease(&subchunk); |
|
return 0; |
|
} |
|
|
|
//------------------------------------------------------------------------------ |
|
// Create a mux object from WebP-RIFF data. |
|
|
|
WebPMux* WebPMuxCreateInternal(const WebPData* bitstream, int copy_data, |
|
int version) { |
|
size_t riff_size; |
|
uint32_t tag; |
|
const uint8_t* end; |
|
WebPMux* mux = NULL; |
|
WebPMuxImage* wpi = NULL; |
|
const uint8_t* data; |
|
size_t size; |
|
WebPChunk chunk; |
|
// Stores the end of the chunk lists so that it is faster to append data to |
|
// their ends. |
|
WebPChunk** chunk_list_ends[WEBP_CHUNK_NIL + 1] = { NULL }; |
|
ChunkInit(&chunk); |
|
|
|
// Sanity checks. |
|
if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_MUX_ABI_VERSION)) { |
|
return NULL; // version mismatch |
|
} |
|
if (bitstream == NULL) return NULL; |
|
|
|
data = bitstream->bytes; |
|
size = bitstream->size; |
|
|
|
if (data == NULL) return NULL; |
|
if (size < RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE) return NULL; |
|
if (GetLE32(data + 0) != MKFOURCC('R', 'I', 'F', 'F') || |
|
GetLE32(data + CHUNK_HEADER_SIZE) != MKFOURCC('W', 'E', 'B', 'P')) { |
|
return NULL; |
|
} |
|
|
|
mux = WebPMuxNew(); |
|
if (mux == NULL) return NULL; |
|
|
|
tag = GetLE32(data + RIFF_HEADER_SIZE); |
|
if (tag != kChunks[IDX_VP8].tag && |
|
tag != kChunks[IDX_VP8L].tag && |
|
tag != kChunks[IDX_VP8X].tag) { |
|
goto Err; // First chunk should be VP8, VP8L or VP8X. |
|
} |
|
|
|
riff_size = GetLE32(data + TAG_SIZE); |
|
if (riff_size > MAX_CHUNK_PAYLOAD) goto Err; |
|
|
|
// Note this padding is historical and differs from demux.c which does not |
|
// pad the file size. |
|
riff_size = SizeWithPadding(riff_size); |
|
if (riff_size < CHUNK_HEADER_SIZE) goto Err; |
|
if (riff_size > size) goto Err; |
|
// There's no point in reading past the end of the RIFF chunk. |
|
if (size > riff_size + CHUNK_HEADER_SIZE) { |
|
size = riff_size + CHUNK_HEADER_SIZE; |
|
} |
|
|
|
end = data + size; |
|
data += RIFF_HEADER_SIZE; |
|
size -= RIFF_HEADER_SIZE; |
|
|
|
wpi = (WebPMuxImage*)WebPSafeMalloc(1ULL, sizeof(*wpi)); |
|
if (wpi == NULL) goto Err; |
|
MuxImageInit(wpi); |
|
|
|
// Loop over chunks. |
|
while (data != end) { |
|
size_t data_size; |
|
WebPChunkId id; |
|
if (ChunkVerifyAndAssign(&chunk, data, size, riff_size, |
|
copy_data) != WEBP_MUX_OK) { |
|
goto Err; |
|
} |
|
data_size = ChunkDiskSize(&chunk); |
|
id = ChunkGetIdFromTag(chunk.tag_); |
|
switch (id) { |
|
case WEBP_CHUNK_ALPHA: |
|
if (wpi->alpha_ != NULL) goto Err; // Consecutive ALPH chunks. |
|
if (ChunkSetHead(&chunk, &wpi->alpha_) != WEBP_MUX_OK) goto Err; |
|
wpi->is_partial_ = 1; // Waiting for a VP8 chunk. |
|
break; |
|
case WEBP_CHUNK_IMAGE: |
|
if (ChunkSetHead(&chunk, &wpi->img_) != WEBP_MUX_OK) goto Err; |
|
if (!MuxImageFinalize(wpi)) goto Err; |
|
wpi->is_partial_ = 0; // wpi is completely filled. |
|
PushImage: |
|
// Add this to mux->images_ list. |
|
if (MuxImagePush(wpi, &mux->images_) != WEBP_MUX_OK) goto Err; |
|
MuxImageInit(wpi); // Reset for reading next image. |
|
break; |
|
case WEBP_CHUNK_ANMF: |
|
if (wpi->is_partial_) goto Err; // Previous wpi is still incomplete. |
|
if (!MuxImageParse(&chunk, copy_data, wpi)) goto Err; |
|
ChunkRelease(&chunk); |
|
goto PushImage; |
|
break; |
|
default: // A non-image chunk. |
|
if (wpi->is_partial_) goto Err; // Encountered a non-image chunk before |
|
// getting all chunks of an image. |
|
if (chunk_list_ends[id] == NULL) { |
|
chunk_list_ends[id] = |
|
MuxGetChunkListFromId(mux, id); // List to add this chunk. |
|
} |
|
if (ChunkAppend(&chunk, &chunk_list_ends[id]) != WEBP_MUX_OK) goto Err; |
|
if (id == WEBP_CHUNK_VP8X) { // grab global specs |
|
if (data_size < CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE) goto Err; |
|
mux->canvas_width_ = GetLE24(data + 12) + 1; |
|
mux->canvas_height_ = GetLE24(data + 15) + 1; |
|
} |
|
break; |
|
} |
|
data += data_size; |
|
size -= data_size; |
|
ChunkInit(&chunk); |
|
} |
|
|
|
// Incomplete image. |
|
if (wpi->is_partial_) goto Err; |
|
|
|
// Validate mux if complete. |
|
if (MuxValidate(mux) != WEBP_MUX_OK) goto Err; |
|
|
|
MuxImageDelete(wpi); |
|
return mux; // All OK; |
|
|
|
Err: // Something bad happened. |
|
ChunkRelease(&chunk); |
|
MuxImageDelete(wpi); |
|
WebPMuxDelete(mux); |
|
return NULL; |
|
} |
|
|
|
//------------------------------------------------------------------------------ |
|
// Get API(s). |
|
|
|
// Validates that the given mux has a single image. |
|
static WebPMuxError ValidateForSingleImage(const WebPMux* const mux) { |
|
const int num_images = MuxImageCount(mux->images_, WEBP_CHUNK_IMAGE); |
|
const int num_frames = MuxImageCount(mux->images_, WEBP_CHUNK_ANMF); |
|
|
|
if (num_images == 0) { |
|
// No images in mux. |
|
return WEBP_MUX_NOT_FOUND; |
|
} else if (num_images == 1 && num_frames == 0) { |
|
// Valid case (single image). |
|
return WEBP_MUX_OK; |
|
} else { |
|
// Frame case OR an invalid mux. |
|
return WEBP_MUX_INVALID_ARGUMENT; |
|
} |
|
} |
|
|
|
// Get the canvas width, height and flags after validating that VP8X/VP8/VP8L |
|
// chunk and canvas size are valid. |
|
static WebPMuxError MuxGetCanvasInfo(const WebPMux* const mux, |
|
int* width, int* height, uint32_t* flags) { |
|
int w, h; |
|
uint32_t f = 0; |
|
WebPData data; |
|
assert(mux != NULL); |
|
|
|
// Check if VP8X chunk is present. |
|
if (MuxGet(mux, IDX_VP8X, 1, &data) == WEBP_MUX_OK) { |
|
if (data.size < VP8X_CHUNK_SIZE) return WEBP_MUX_BAD_DATA; |
|
f = GetLE32(data.bytes + 0); |
|
w = GetLE24(data.bytes + 4) + 1; |
|
h = GetLE24(data.bytes + 7) + 1; |
|
} else { |
|
const WebPMuxImage* const wpi = mux->images_; |
|
// Grab user-forced canvas size as default. |
|
w = mux->canvas_width_; |
|
h = mux->canvas_height_; |
|
if (w == 0 && h == 0 && ValidateForSingleImage(mux) == WEBP_MUX_OK) { |
|
// single image and not forced canvas size => use dimension of first frame |
|
assert(wpi != NULL); |
|
w = wpi->width_; |
|
h = wpi->height_; |
|
} |
|
if (wpi != NULL) { |
|
if (wpi->has_alpha_) f |= ALPHA_FLAG; |
|
} |
|
} |
|
if (w * (uint64_t)h >= MAX_IMAGE_AREA) return WEBP_MUX_BAD_DATA; |
|
|
|
if (width != NULL) *width = w; |
|
if (height != NULL) *height = h; |
|
if (flags != NULL) *flags = f; |
|
return WEBP_MUX_OK; |
|
} |
|
|
|
WebPMuxError WebPMuxGetCanvasSize(const WebPMux* mux, int* width, int* height) { |
|
if (mux == NULL || width == NULL || height == NULL) { |
|
return WEBP_MUX_INVALID_ARGUMENT; |
|
} |
|
return MuxGetCanvasInfo(mux, width, height, NULL); |
|
} |
|
|
|
WebPMuxError WebPMuxGetFeatures(const WebPMux* mux, uint32_t* flags) { |
|
if (mux == NULL || flags == NULL) return WEBP_MUX_INVALID_ARGUMENT; |
|
return MuxGetCanvasInfo(mux, NULL, NULL, flags); |
|
} |
|
|
|
static uint8_t* EmitVP8XChunk(uint8_t* const dst, int width, |
|
int height, uint32_t flags) { |
|
const size_t vp8x_size = CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE; |
|
assert(width >= 1 && height >= 1); |
|
assert(width <= MAX_CANVAS_SIZE && height <= MAX_CANVAS_SIZE); |
|
assert(width * (uint64_t)height < MAX_IMAGE_AREA); |
|
PutLE32(dst, MKFOURCC('V', 'P', '8', 'X')); |
|
PutLE32(dst + TAG_SIZE, VP8X_CHUNK_SIZE); |
|
PutLE32(dst + CHUNK_HEADER_SIZE, flags); |
|
PutLE24(dst + CHUNK_HEADER_SIZE + 4, width - 1); |
|
PutLE24(dst + CHUNK_HEADER_SIZE + 7, height - 1); |
|
return dst + vp8x_size; |
|
} |
|
|
|
// 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 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; |
|
|
|
// There should be at most one alpha_ chunk and exactly one img_ chunk. |
|
assert(wpi->alpha_ == NULL || wpi->alpha_->next_ == NULL); |
|
assert(wpi->img_ != NULL && wpi->img_->next_ == NULL); |
|
|
|
// 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; |
|
} |
|
|
|
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; |
|
} |
|
} |
|
|
|
static WebPMuxError MuxGetImageInternal(const WebPMuxImage* const wpi, |
|
WebPMuxFrameInfo* const info) { |
|
// Set some defaults for unrelated fields. |
|
info->x_offset = 0; |
|
info->y_offset = 0; |
|
info->duration = 1; |
|
info->dispose_method = WEBP_MUX_DISPOSE_NONE; |
|
info->blend_method = WEBP_MUX_BLEND; |
|
// Extract data for related fields. |
|
info->id = ChunkGetIdFromTag(wpi->img_->tag_); |
|
return SynthesizeBitstream(wpi, &info->bitstream); |
|
} |
|
|
|
static WebPMuxError MuxGetFrameInternal(const WebPMuxImage* const wpi, |
|
WebPMuxFrameInfo* const frame) { |
|
const int is_frame = (wpi->header_->tag_ == kChunks[IDX_ANMF].tag); |
|
const WebPData* frame_data; |
|
if (!is_frame) return WEBP_MUX_INVALID_ARGUMENT; |
|
assert(wpi->header_ != NULL); // Already checked by WebPMuxGetFrame(). |
|
// Get frame chunk. |
|
frame_data = &wpi->header_->data_; |
|
if (frame_data->size < kChunks[IDX_ANMF].size) return WEBP_MUX_BAD_DATA; |
|
// Extract info. |
|
frame->x_offset = 2 * GetLE24(frame_data->bytes + 0); |
|
frame->y_offset = 2 * GetLE24(frame_data->bytes + 3); |
|
{ |
|
const uint8_t bits = frame_data->bytes[15]; |
|
frame->duration = GetLE24(frame_data->bytes + 12); |
|
frame->dispose_method = |
|
(bits & 1) ? WEBP_MUX_DISPOSE_BACKGROUND : WEBP_MUX_DISPOSE_NONE; |
|
frame->blend_method = (bits & 2) ? WEBP_MUX_NO_BLEND : WEBP_MUX_BLEND; |
|
} |
|
frame->id = ChunkGetIdFromTag(wpi->header_->tag_); |
|
return SynthesizeBitstream(wpi, &frame->bitstream); |
|
} |
|
|
|
WebPMuxError WebPMuxGetFrame( |
|
const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame) { |
|
WebPMuxError err; |
|
WebPMuxImage* wpi; |
|
|
|
// Sanity checks. |
|
if (mux == NULL || frame == NULL) { |
|
return WEBP_MUX_INVALID_ARGUMENT; |
|
} |
|
|
|
// Get the nth WebPMuxImage. |
|
err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, nth, &wpi); |
|
if (err != WEBP_MUX_OK) return err; |
|
|
|
// Get frame info. |
|
if (wpi->header_ == NULL) { |
|
return MuxGetImageInternal(wpi, frame); |
|
} else { |
|
return MuxGetFrameInternal(wpi, frame); |
|
} |
|
} |
|
|
|
WebPMuxError WebPMuxGetAnimationParams(const WebPMux* mux, |
|
WebPMuxAnimParams* params) { |
|
WebPData anim; |
|
WebPMuxError err; |
|
|
|
if (mux == NULL || params == NULL) return WEBP_MUX_INVALID_ARGUMENT; |
|
|
|
err = MuxGet(mux, IDX_ANIM, 1, &anim); |
|
if (err != WEBP_MUX_OK) return err; |
|
if (anim.size < kChunks[WEBP_CHUNK_ANIM].size) return WEBP_MUX_BAD_DATA; |
|
params->bgcolor = GetLE32(anim.bytes); |
|
params->loop_count = GetLE16(anim.bytes + 4); |
|
|
|
return WEBP_MUX_OK; |
|
} |
|
|
|
// Get chunk index from chunk id. Returns IDX_NIL if not found. |
|
static CHUNK_INDEX ChunkGetIndexFromId(WebPChunkId id) { |
|
int i; |
|
for (i = 0; kChunks[i].id != WEBP_CHUNK_NIL; ++i) { |
|
if (id == kChunks[i].id) return (CHUNK_INDEX)i; |
|
} |
|
return IDX_NIL; |
|
} |
|
|
|
// Count number of chunks matching 'tag' in the 'chunk_list'. |
|
// If tag == NIL_TAG, any tag will be matched. |
|
static int CountChunks(const WebPChunk* const chunk_list, uint32_t tag) { |
|
int count = 0; |
|
const 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; |
|
} |
|
|
|
WebPMuxError WebPMuxNumChunks(const WebPMux* mux, |
|
WebPChunkId id, int* num_elements) { |
|
if (mux == NULL || num_elements == NULL) { |
|
return WEBP_MUX_INVALID_ARGUMENT; |
|
} |
|
|
|
if (IsWPI(id)) { |
|
*num_elements = MuxImageCount(mux->images_, id); |
|
} else { |
|
WebPChunk* const* chunk_list = MuxGetChunkListFromId(mux, id); |
|
const CHUNK_INDEX idx = ChunkGetIndexFromId(id); |
|
*num_elements = CountChunks(*chunk_list, kChunks[idx].tag); |
|
} |
|
|
|
return WEBP_MUX_OK; |
|
} |
|
|
|
//------------------------------------------------------------------------------
|
|
|