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965 lines
31 KiB
965 lines
31 KiB
// Copyright 2012 Google Inc. All Rights Reserved. |
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// |
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// Use of this source code is governed by a BSD-style license |
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// that can be found in the COPYING file in the root of the source |
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// tree. An additional intellectual property rights grant can be found |
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// in the file PATENTS. All contributing project authors may |
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// be found in the AUTHORS file in the root of the source tree. |
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// ----------------------------------------------------------------------------- |
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// |
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// WebP container demux. |
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// |
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#ifdef HAVE_CONFIG_H |
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#include "../webp/config.h" |
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#endif |
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#include <assert.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include "../utils/utils.h" |
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#include "../webp/decode.h" // WebPGetFeatures |
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#include "../webp/demux.h" |
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#include "../webp/format_constants.h" |
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#define DMUX_MAJ_VERSION 0 |
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#define DMUX_MIN_VERSION 3 |
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#define DMUX_REV_VERSION 2 |
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typedef struct { |
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size_t start_; // start location of the data |
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size_t end_; // end location |
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size_t riff_end_; // riff chunk end location, can be > end_. |
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size_t buf_size_; // size of the buffer |
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const uint8_t* buf_; |
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} MemBuffer; |
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typedef struct { |
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size_t offset_; |
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size_t size_; |
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} ChunkData; |
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typedef struct Frame { |
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int x_offset_, y_offset_; |
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int width_, height_; |
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int has_alpha_; |
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int duration_; |
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WebPMuxAnimDispose dispose_method_; |
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WebPMuxAnimBlend blend_method_; |
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int frame_num_; |
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int complete_; // img_components_ contains a full image. |
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ChunkData img_components_[2]; // 0=VP8{,L} 1=ALPH |
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struct Frame* next_; |
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} Frame; |
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typedef struct Chunk { |
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ChunkData data_; |
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struct Chunk* next_; |
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} Chunk; |
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struct WebPDemuxer { |
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MemBuffer mem_; |
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WebPDemuxState state_; |
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int is_ext_format_; |
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uint32_t feature_flags_; |
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int canvas_width_, canvas_height_; |
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int loop_count_; |
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uint32_t bgcolor_; |
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int num_frames_; |
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Frame* frames_; |
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Frame** frames_tail_; |
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Chunk* chunks_; // non-image chunks |
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Chunk** chunks_tail_; |
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}; |
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typedef enum { |
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PARSE_OK, |
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PARSE_NEED_MORE_DATA, |
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PARSE_ERROR |
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} ParseStatus; |
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typedef struct ChunkParser { |
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uint8_t id[4]; |
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ParseStatus (*parse)(WebPDemuxer* const dmux); |
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int (*valid)(const WebPDemuxer* const dmux); |
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} ChunkParser; |
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static ParseStatus ParseSingleImage(WebPDemuxer* const dmux); |
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static ParseStatus ParseVP8X(WebPDemuxer* const dmux); |
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static int IsValidSimpleFormat(const WebPDemuxer* const dmux); |
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static int IsValidExtendedFormat(const WebPDemuxer* const dmux); |
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static const ChunkParser kMasterChunks[] = { |
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{ { 'V', 'P', '8', ' ' }, ParseSingleImage, IsValidSimpleFormat }, |
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{ { 'V', 'P', '8', 'L' }, ParseSingleImage, IsValidSimpleFormat }, |
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{ { 'V', 'P', '8', 'X' }, ParseVP8X, IsValidExtendedFormat }, |
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{ { '0', '0', '0', '0' }, NULL, NULL }, |
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}; |
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//------------------------------------------------------------------------------ |
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int WebPGetDemuxVersion(void) { |
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return (DMUX_MAJ_VERSION << 16) | (DMUX_MIN_VERSION << 8) | DMUX_REV_VERSION; |
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} |
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// ----------------------------------------------------------------------------- |
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// MemBuffer |
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static int RemapMemBuffer(MemBuffer* const mem, |
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const uint8_t* data, size_t size) { |
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if (size < mem->buf_size_) return 0; // can't remap to a shorter buffer! |
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mem->buf_ = data; |
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mem->end_ = mem->buf_size_ = size; |
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return 1; |
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} |
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static int InitMemBuffer(MemBuffer* const mem, |
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const uint8_t* data, size_t size) { |
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memset(mem, 0, sizeof(*mem)); |
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return RemapMemBuffer(mem, data, size); |
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} |
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// Return the remaining data size available in 'mem'. |
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static WEBP_INLINE size_t MemDataSize(const MemBuffer* const mem) { |
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return (mem->end_ - mem->start_); |
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} |
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// Return true if 'size' exceeds the end of the RIFF chunk. |
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static WEBP_INLINE int SizeIsInvalid(const MemBuffer* const mem, size_t size) { |
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return (size > mem->riff_end_ - mem->start_); |
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} |
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static WEBP_INLINE void Skip(MemBuffer* const mem, size_t size) { |
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mem->start_ += size; |
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} |
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static WEBP_INLINE void Rewind(MemBuffer* const mem, size_t size) { |
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mem->start_ -= size; |
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} |
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static WEBP_INLINE const uint8_t* GetBuffer(MemBuffer* const mem) { |
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return mem->buf_ + mem->start_; |
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} |
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// Read from 'mem' and skip the read bytes. |
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static WEBP_INLINE uint8_t ReadByte(MemBuffer* const mem) { |
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const uint8_t byte = mem->buf_[mem->start_]; |
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Skip(mem, 1); |
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return byte; |
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} |
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static WEBP_INLINE int ReadLE16s(MemBuffer* const mem) { |
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const uint8_t* const data = mem->buf_ + mem->start_; |
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const int val = GetLE16(data); |
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Skip(mem, 2); |
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return val; |
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} |
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static WEBP_INLINE int ReadLE24s(MemBuffer* const mem) { |
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const uint8_t* const data = mem->buf_ + mem->start_; |
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const int val = GetLE24(data); |
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Skip(mem, 3); |
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return val; |
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} |
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static WEBP_INLINE uint32_t ReadLE32(MemBuffer* const mem) { |
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const uint8_t* const data = mem->buf_ + mem->start_; |
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const uint32_t val = GetLE32(data); |
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Skip(mem, 4); |
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return val; |
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} |
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// ----------------------------------------------------------------------------- |
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// Secondary chunk parsing |
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static void AddChunk(WebPDemuxer* const dmux, Chunk* const chunk) { |
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*dmux->chunks_tail_ = chunk; |
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chunk->next_ = NULL; |
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dmux->chunks_tail_ = &chunk->next_; |
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} |
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// Add a frame to the end of the list, ensuring the last frame is complete. |
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// Returns true on success, false otherwise. |
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static int AddFrame(WebPDemuxer* const dmux, Frame* const frame) { |
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const Frame* const last_frame = *dmux->frames_tail_; |
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if (last_frame != NULL && !last_frame->complete_) return 0; |
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*dmux->frames_tail_ = frame; |
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frame->next_ = NULL; |
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dmux->frames_tail_ = &frame->next_; |
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return 1; |
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} |
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static void SetFrameInfo(size_t start_offset, size_t size, |
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int frame_num, int complete, |
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const WebPBitstreamFeatures* const features, |
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Frame* const frame) { |
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frame->img_components_[0].offset_ = start_offset; |
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frame->img_components_[0].size_ = size; |
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frame->width_ = features->width; |
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frame->height_ = features->height; |
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frame->has_alpha_ |= features->has_alpha; |
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frame->frame_num_ = frame_num; |
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frame->complete_ = complete; |
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} |
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// Store image bearing chunks to 'frame'. |
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static ParseStatus StoreFrame(int frame_num, uint32_t min_size, |
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MemBuffer* const mem, Frame* const frame) { |
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int alpha_chunks = 0; |
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int image_chunks = 0; |
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int done = (MemDataSize(mem) < min_size); |
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ParseStatus status = PARSE_OK; |
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if (done) return PARSE_NEED_MORE_DATA; |
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do { |
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const size_t chunk_start_offset = mem->start_; |
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const uint32_t fourcc = ReadLE32(mem); |
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const uint32_t payload_size = ReadLE32(mem); |
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const uint32_t payload_size_padded = payload_size + (payload_size & 1); |
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const size_t payload_available = (payload_size_padded > MemDataSize(mem)) |
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? MemDataSize(mem) : payload_size_padded; |
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const size_t chunk_size = CHUNK_HEADER_SIZE + payload_available; |
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if (payload_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
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if (SizeIsInvalid(mem, payload_size_padded)) return PARSE_ERROR; |
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if (payload_size_padded > MemDataSize(mem)) status = PARSE_NEED_MORE_DATA; |
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switch (fourcc) { |
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case MKFOURCC('A', 'L', 'P', 'H'): |
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if (alpha_chunks == 0) { |
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++alpha_chunks; |
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frame->img_components_[1].offset_ = chunk_start_offset; |
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frame->img_components_[1].size_ = chunk_size; |
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frame->has_alpha_ = 1; |
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frame->frame_num_ = frame_num; |
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Skip(mem, payload_available); |
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} else { |
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goto Done; |
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} |
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break; |
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case MKFOURCC('V', 'P', '8', 'L'): |
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if (alpha_chunks > 0) return PARSE_ERROR; // VP8L has its own alpha |
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// fall through |
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case MKFOURCC('V', 'P', '8', ' '): |
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if (image_chunks == 0) { |
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// Extract the bitstream features, tolerating failures when the data |
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// is incomplete. |
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WebPBitstreamFeatures features; |
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const VP8StatusCode vp8_status = |
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WebPGetFeatures(mem->buf_ + chunk_start_offset, chunk_size, |
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&features); |
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if (status == PARSE_NEED_MORE_DATA && |
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vp8_status == VP8_STATUS_NOT_ENOUGH_DATA) { |
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return PARSE_NEED_MORE_DATA; |
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} else if (vp8_status != VP8_STATUS_OK) { |
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// We have enough data, and yet WebPGetFeatures() failed. |
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return PARSE_ERROR; |
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} |
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++image_chunks; |
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SetFrameInfo(chunk_start_offset, chunk_size, frame_num, |
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status == PARSE_OK, &features, frame); |
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Skip(mem, payload_available); |
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} else { |
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goto Done; |
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} |
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break; |
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Done: |
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default: |
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// Restore fourcc/size when moving up one level in parsing. |
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Rewind(mem, CHUNK_HEADER_SIZE); |
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done = 1; |
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break; |
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} |
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if (mem->start_ == mem->riff_end_) { |
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done = 1; |
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} else if (MemDataSize(mem) < CHUNK_HEADER_SIZE) { |
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status = PARSE_NEED_MORE_DATA; |
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} |
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} while (!done && status == PARSE_OK); |
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return status; |
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} |
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// Creates a new Frame if 'actual_size' is within bounds and 'mem' contains |
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// enough data ('min_size') to parse the payload. |
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// Returns PARSE_OK on success with *frame pointing to the new Frame. |
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// Returns PARSE_NEED_MORE_DATA with insufficient data, PARSE_ERROR otherwise. |
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static ParseStatus NewFrame(const MemBuffer* const mem, |
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uint32_t min_size, uint32_t actual_size, |
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Frame** frame) { |
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if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR; |
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if (actual_size < min_size) return PARSE_ERROR; |
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if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; |
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*frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(**frame)); |
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return (*frame == NULL) ? PARSE_ERROR : PARSE_OK; |
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} |
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// Parse a 'ANMF' chunk and any image bearing chunks that immediately follow. |
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// 'frame_chunk_size' is the previously validated, padded chunk size. |
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static ParseStatus ParseAnimationFrame( |
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WebPDemuxer* const dmux, uint32_t frame_chunk_size) { |
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const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG); |
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const uint32_t anmf_payload_size = frame_chunk_size - ANMF_CHUNK_SIZE; |
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int added_frame = 0; |
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int bits; |
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MemBuffer* const mem = &dmux->mem_; |
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Frame* frame; |
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ParseStatus status = |
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NewFrame(mem, ANMF_CHUNK_SIZE, frame_chunk_size, &frame); |
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if (status != PARSE_OK) return status; |
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frame->x_offset_ = 2 * ReadLE24s(mem); |
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frame->y_offset_ = 2 * ReadLE24s(mem); |
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frame->width_ = 1 + ReadLE24s(mem); |
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frame->height_ = 1 + ReadLE24s(mem); |
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frame->duration_ = ReadLE24s(mem); |
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bits = ReadByte(mem); |
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frame->dispose_method_ = |
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(bits & 1) ? WEBP_MUX_DISPOSE_BACKGROUND : WEBP_MUX_DISPOSE_NONE; |
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frame->blend_method_ = (bits & 2) ? WEBP_MUX_NO_BLEND : WEBP_MUX_BLEND; |
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if (frame->width_ * (uint64_t)frame->height_ >= MAX_IMAGE_AREA) { |
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WebPSafeFree(frame); |
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return PARSE_ERROR; |
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} |
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// Store a frame only if the animation flag is set there is some data for |
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// this frame is available. |
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status = StoreFrame(dmux->num_frames_ + 1, anmf_payload_size, mem, frame); |
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if (status != PARSE_ERROR && is_animation && frame->frame_num_ > 0) { |
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added_frame = AddFrame(dmux, frame); |
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if (added_frame) { |
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++dmux->num_frames_; |
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} else { |
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status = PARSE_ERROR; |
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} |
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} |
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if (!added_frame) WebPSafeFree(frame); |
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return status; |
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} |
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// General chunk storage, starting with the header at 'start_offset', allowing |
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// the user to request the payload via a fourcc string. 'size' includes the |
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// header and the unpadded payload size. |
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// Returns true on success, false otherwise. |
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static int StoreChunk(WebPDemuxer* const dmux, |
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size_t start_offset, uint32_t size) { |
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Chunk* const chunk = (Chunk*)WebPSafeCalloc(1ULL, sizeof(*chunk)); |
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if (chunk == NULL) return 0; |
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chunk->data_.offset_ = start_offset; |
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chunk->data_.size_ = size; |
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AddChunk(dmux, chunk); |
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return 1; |
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} |
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// ----------------------------------------------------------------------------- |
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// Primary chunk parsing |
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static ParseStatus ReadHeader(MemBuffer* const mem) { |
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const size_t min_size = RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE; |
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uint32_t riff_size; |
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|
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// Basic file level validation. |
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if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; |
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if (memcmp(GetBuffer(mem), "RIFF", CHUNK_SIZE_BYTES) || |
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memcmp(GetBuffer(mem) + CHUNK_HEADER_SIZE, "WEBP", CHUNK_SIZE_BYTES)) { |
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return PARSE_ERROR; |
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} |
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riff_size = GetLE32(GetBuffer(mem) + TAG_SIZE); |
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if (riff_size < CHUNK_HEADER_SIZE) return PARSE_ERROR; |
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if (riff_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
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|
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// There's no point in reading past the end of the RIFF chunk |
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mem->riff_end_ = riff_size + CHUNK_HEADER_SIZE; |
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if (mem->buf_size_ > mem->riff_end_) { |
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mem->buf_size_ = mem->end_ = mem->riff_end_; |
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} |
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Skip(mem, RIFF_HEADER_SIZE); |
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return PARSE_OK; |
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} |
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static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) { |
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const size_t min_size = CHUNK_HEADER_SIZE; |
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MemBuffer* const mem = &dmux->mem_; |
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Frame* frame; |
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ParseStatus status; |
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int image_added = 0; |
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|
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if (dmux->frames_ != NULL) return PARSE_ERROR; |
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if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR; |
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if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; |
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frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(*frame)); |
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if (frame == NULL) return PARSE_ERROR; |
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|
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// For the single image case we allow parsing of a partial frame, but we need |
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// at least CHUNK_HEADER_SIZE for parsing. |
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status = StoreFrame(1, CHUNK_HEADER_SIZE, &dmux->mem_, frame); |
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if (status != PARSE_ERROR) { |
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const int has_alpha = !!(dmux->feature_flags_ & ALPHA_FLAG); |
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// Clear any alpha when the alpha flag is missing. |
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if (!has_alpha && frame->img_components_[1].size_ > 0) { |
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frame->img_components_[1].offset_ = 0; |
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frame->img_components_[1].size_ = 0; |
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frame->has_alpha_ = 0; |
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} |
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|
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// Use the frame width/height as the canvas values for non-vp8x files. |
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// Also, set ALPHA_FLAG if this is a lossless image with alpha. |
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if (!dmux->is_ext_format_ && frame->width_ > 0 && frame->height_ > 0) { |
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dmux->state_ = WEBP_DEMUX_PARSED_HEADER; |
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dmux->canvas_width_ = frame->width_; |
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dmux->canvas_height_ = frame->height_; |
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dmux->feature_flags_ |= frame->has_alpha_ ? ALPHA_FLAG : 0; |
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} |
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if (!AddFrame(dmux, frame)) { |
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status = PARSE_ERROR; // last frame was left incomplete |
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} else { |
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image_added = 1; |
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dmux->num_frames_ = 1; |
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} |
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} |
|
|
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if (!image_added) WebPSafeFree(frame); |
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return status; |
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} |
|
|
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static ParseStatus ParseVP8XChunks(WebPDemuxer* const dmux) { |
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const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG); |
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MemBuffer* const mem = &dmux->mem_; |
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int anim_chunks = 0; |
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ParseStatus status = PARSE_OK; |
|
|
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do { |
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int store_chunk = 1; |
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const size_t chunk_start_offset = mem->start_; |
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const uint32_t fourcc = ReadLE32(mem); |
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const uint32_t chunk_size = ReadLE32(mem); |
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const uint32_t chunk_size_padded = chunk_size + (chunk_size & 1); |
|
|
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if (chunk_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
|
if (SizeIsInvalid(mem, chunk_size_padded)) return PARSE_ERROR; |
|
|
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switch (fourcc) { |
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case MKFOURCC('V', 'P', '8', 'X'): { |
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return PARSE_ERROR; |
|
} |
|
case MKFOURCC('A', 'L', 'P', 'H'): |
|
case MKFOURCC('V', 'P', '8', ' '): |
|
case MKFOURCC('V', 'P', '8', 'L'): { |
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// check that this isn't an animation (all frames should be in an ANMF). |
|
if (anim_chunks > 0 || is_animation) return PARSE_ERROR; |
|
|
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Rewind(mem, CHUNK_HEADER_SIZE); |
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status = ParseSingleImage(dmux); |
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break; |
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} |
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case MKFOURCC('A', 'N', 'I', 'M'): { |
|
if (chunk_size_padded < ANIM_CHUNK_SIZE) return PARSE_ERROR; |
|
|
|
if (MemDataSize(mem) < chunk_size_padded) { |
|
status = PARSE_NEED_MORE_DATA; |
|
} else if (anim_chunks == 0) { |
|
++anim_chunks; |
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dmux->bgcolor_ = ReadLE32(mem); |
|
dmux->loop_count_ = ReadLE16s(mem); |
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Skip(mem, chunk_size_padded - ANIM_CHUNK_SIZE); |
|
} else { |
|
store_chunk = 0; |
|
goto Skip; |
|
} |
|
break; |
|
} |
|
case MKFOURCC('A', 'N', 'M', 'F'): { |
|
if (anim_chunks == 0) return PARSE_ERROR; // 'ANIM' precedes frames. |
|
status = ParseAnimationFrame(dmux, chunk_size_padded); |
|
break; |
|
} |
|
case MKFOURCC('I', 'C', 'C', 'P'): { |
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store_chunk = !!(dmux->feature_flags_ & ICCP_FLAG); |
|
goto Skip; |
|
} |
|
case MKFOURCC('E', 'X', 'I', 'F'): { |
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store_chunk = !!(dmux->feature_flags_ & EXIF_FLAG); |
|
goto Skip; |
|
} |
|
case MKFOURCC('X', 'M', 'P', ' '): { |
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store_chunk = !!(dmux->feature_flags_ & XMP_FLAG); |
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goto Skip; |
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} |
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Skip: |
|
default: { |
|
if (chunk_size_padded <= MemDataSize(mem)) { |
|
if (store_chunk) { |
|
// Store only the chunk header and unpadded size as only the payload |
|
// will be returned to the user. |
|
if (!StoreChunk(dmux, chunk_start_offset, |
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CHUNK_HEADER_SIZE + chunk_size)) { |
|
return PARSE_ERROR; |
|
} |
|
} |
|
Skip(mem, chunk_size_padded); |
|
} else { |
|
status = PARSE_NEED_MORE_DATA; |
|
} |
|
} |
|
} |
|
|
|
if (mem->start_ == mem->riff_end_) { |
|
break; |
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} else if (MemDataSize(mem) < CHUNK_HEADER_SIZE) { |
|
status = PARSE_NEED_MORE_DATA; |
|
} |
|
} while (status == PARSE_OK); |
|
|
|
return status; |
|
} |
|
|
|
static ParseStatus ParseVP8X(WebPDemuxer* const dmux) { |
|
MemBuffer* const mem = &dmux->mem_; |
|
uint32_t vp8x_size; |
|
|
|
if (MemDataSize(mem) < CHUNK_HEADER_SIZE) return PARSE_NEED_MORE_DATA; |
|
|
|
dmux->is_ext_format_ = 1; |
|
Skip(mem, TAG_SIZE); // VP8X |
|
vp8x_size = ReadLE32(mem); |
|
if (vp8x_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; |
|
if (vp8x_size < VP8X_CHUNK_SIZE) return PARSE_ERROR; |
|
vp8x_size += vp8x_size & 1; |
|
if (SizeIsInvalid(mem, vp8x_size)) return PARSE_ERROR; |
|
if (MemDataSize(mem) < vp8x_size) return PARSE_NEED_MORE_DATA; |
|
|
|
dmux->feature_flags_ = ReadByte(mem); |
|
Skip(mem, 3); // Reserved. |
|
dmux->canvas_width_ = 1 + ReadLE24s(mem); |
|
dmux->canvas_height_ = 1 + ReadLE24s(mem); |
|
if (dmux->canvas_width_ * (uint64_t)dmux->canvas_height_ >= MAX_IMAGE_AREA) { |
|
return PARSE_ERROR; // image final dimension is too large |
|
} |
|
Skip(mem, vp8x_size - VP8X_CHUNK_SIZE); // skip any trailing data. |
|
dmux->state_ = WEBP_DEMUX_PARSED_HEADER; |
|
|
|
if (SizeIsInvalid(mem, CHUNK_HEADER_SIZE)) return PARSE_ERROR; |
|
if (MemDataSize(mem) < CHUNK_HEADER_SIZE) return PARSE_NEED_MORE_DATA; |
|
|
|
return ParseVP8XChunks(dmux); |
|
} |
|
|
|
// ----------------------------------------------------------------------------- |
|
// Format validation |
|
|
|
static int IsValidSimpleFormat(const WebPDemuxer* const dmux) { |
|
const Frame* const frame = dmux->frames_; |
|
if (dmux->state_ == WEBP_DEMUX_PARSING_HEADER) return 1; |
|
|
|
if (dmux->canvas_width_ <= 0 || dmux->canvas_height_ <= 0) return 0; |
|
if (dmux->state_ == WEBP_DEMUX_DONE && frame == NULL) return 0; |
|
|
|
if (frame->width_ <= 0 || frame->height_ <= 0) return 0; |
|
return 1; |
|
} |
|
|
|
// If 'exact' is true, check that the image resolution matches the canvas. |
|
// If 'exact' is false, check that the x/y offsets do not exceed the canvas. |
|
static int CheckFrameBounds(const Frame* const frame, int exact, |
|
int canvas_width, int canvas_height) { |
|
if (exact) { |
|
if (frame->x_offset_ != 0 || frame->y_offset_ != 0) { |
|
return 0; |
|
} |
|
if (frame->width_ != canvas_width || frame->height_ != canvas_height) { |
|
return 0; |
|
} |
|
} else { |
|
if (frame->x_offset_ < 0 || frame->y_offset_ < 0) return 0; |
|
if (frame->width_ + frame->x_offset_ > canvas_width) return 0; |
|
if (frame->height_ + frame->y_offset_ > canvas_height) return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
static int IsValidExtendedFormat(const WebPDemuxer* const dmux) { |
|
const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG); |
|
const Frame* f = dmux->frames_; |
|
|
|
if (dmux->state_ == WEBP_DEMUX_PARSING_HEADER) return 1; |
|
|
|
if (dmux->canvas_width_ <= 0 || dmux->canvas_height_ <= 0) return 0; |
|
if (dmux->loop_count_ < 0) return 0; |
|
if (dmux->state_ == WEBP_DEMUX_DONE && dmux->frames_ == NULL) return 0; |
|
if (dmux->feature_flags_ & ~ALL_VALID_FLAGS) return 0; // invalid bitstream |
|
|
|
while (f != NULL) { |
|
const int cur_frame_set = f->frame_num_; |
|
int frame_count = 0; |
|
|
|
// Check frame properties. |
|
for (; f != NULL && f->frame_num_ == cur_frame_set; f = f->next_) { |
|
const ChunkData* const image = f->img_components_; |
|
const ChunkData* const alpha = f->img_components_ + 1; |
|
|
|
if (!is_animation && f->frame_num_ > 1) return 0; |
|
|
|
if (f->complete_) { |
|
if (alpha->size_ == 0 && image->size_ == 0) return 0; |
|
// Ensure alpha precedes image bitstream. |
|
if (alpha->size_ > 0 && alpha->offset_ > image->offset_) { |
|
return 0; |
|
} |
|
|
|
if (f->width_ <= 0 || f->height_ <= 0) return 0; |
|
} else { |
|
// There shouldn't be a partial frame in a complete file. |
|
if (dmux->state_ == WEBP_DEMUX_DONE) return 0; |
|
|
|
// Ensure alpha precedes image bitstream. |
|
if (alpha->size_ > 0 && image->size_ > 0 && |
|
alpha->offset_ > image->offset_) { |
|
return 0; |
|
} |
|
// There shouldn't be any frames after an incomplete one. |
|
if (f->next_ != NULL) return 0; |
|
} |
|
|
|
if (f->width_ > 0 && f->height_ > 0 && |
|
!CheckFrameBounds(f, !is_animation, |
|
dmux->canvas_width_, dmux->canvas_height_)) { |
|
return 0; |
|
} |
|
|
|
++frame_count; |
|
} |
|
} |
|
return 1; |
|
} |
|
|
|
// ----------------------------------------------------------------------------- |
|
// WebPDemuxer object |
|
|
|
static void InitDemux(WebPDemuxer* const dmux, const MemBuffer* const mem) { |
|
dmux->state_ = WEBP_DEMUX_PARSING_HEADER; |
|
dmux->loop_count_ = 1; |
|
dmux->bgcolor_ = 0xFFFFFFFF; // White background by default. |
|
dmux->canvas_width_ = -1; |
|
dmux->canvas_height_ = -1; |
|
dmux->frames_tail_ = &dmux->frames_; |
|
dmux->chunks_tail_ = &dmux->chunks_; |
|
dmux->mem_ = *mem; |
|
} |
|
|
|
static ParseStatus CreateRawImageDemuxer(MemBuffer* const mem, |
|
WebPDemuxer** demuxer) { |
|
WebPBitstreamFeatures features; |
|
const VP8StatusCode status = |
|
WebPGetFeatures(mem->buf_, mem->buf_size_, &features); |
|
*demuxer = NULL; |
|
if (status != VP8_STATUS_OK) { |
|
return (status == VP8_STATUS_NOT_ENOUGH_DATA) ? PARSE_NEED_MORE_DATA |
|
: PARSE_ERROR; |
|
} |
|
|
|
{ |
|
WebPDemuxer* const dmux = (WebPDemuxer*)WebPSafeCalloc(1ULL, sizeof(*dmux)); |
|
Frame* const frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(*frame)); |
|
if (dmux == NULL || frame == NULL) goto Error; |
|
InitDemux(dmux, mem); |
|
SetFrameInfo(0, mem->buf_size_, 1 /*frame_num*/, 1 /*complete*/, &features, |
|
frame); |
|
if (!AddFrame(dmux, frame)) goto Error; |
|
dmux->state_ = WEBP_DEMUX_DONE; |
|
dmux->canvas_width_ = frame->width_; |
|
dmux->canvas_height_ = frame->height_; |
|
dmux->feature_flags_ |= frame->has_alpha_ ? ALPHA_FLAG : 0; |
|
dmux->num_frames_ = 1; |
|
assert(IsValidSimpleFormat(dmux)); |
|
*demuxer = dmux; |
|
return PARSE_OK; |
|
|
|
Error: |
|
WebPSafeFree(dmux); |
|
WebPSafeFree(frame); |
|
return PARSE_ERROR; |
|
} |
|
} |
|
|
|
WebPDemuxer* WebPDemuxInternal(const WebPData* data, int allow_partial, |
|
WebPDemuxState* state, int version) { |
|
const ChunkParser* parser; |
|
int partial; |
|
ParseStatus status = PARSE_ERROR; |
|
MemBuffer mem; |
|
WebPDemuxer* dmux; |
|
|
|
if (state != NULL) *state = WEBP_DEMUX_PARSE_ERROR; |
|
|
|
if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DEMUX_ABI_VERSION)) return NULL; |
|
if (data == NULL || data->bytes == NULL || data->size == 0) return NULL; |
|
|
|
if (!InitMemBuffer(&mem, data->bytes, data->size)) return NULL; |
|
status = ReadHeader(&mem); |
|
if (status != PARSE_OK) { |
|
// If parsing of the webp file header fails attempt to handle a raw |
|
// VP8/VP8L frame. Note 'allow_partial' is ignored in this case. |
|
if (status == PARSE_ERROR) { |
|
status = CreateRawImageDemuxer(&mem, &dmux); |
|
if (status == PARSE_OK) { |
|
if (state != NULL) *state = WEBP_DEMUX_DONE; |
|
return dmux; |
|
} |
|
} |
|
if (state != NULL) { |
|
*state = (status == PARSE_NEED_MORE_DATA) ? WEBP_DEMUX_PARSING_HEADER |
|
: WEBP_DEMUX_PARSE_ERROR; |
|
} |
|
return NULL; |
|
} |
|
|
|
partial = (mem.buf_size_ < mem.riff_end_); |
|
if (!allow_partial && partial) return NULL; |
|
|
|
dmux = (WebPDemuxer*)WebPSafeCalloc(1ULL, sizeof(*dmux)); |
|
if (dmux == NULL) return NULL; |
|
InitDemux(dmux, &mem); |
|
|
|
status = PARSE_ERROR; |
|
for (parser = kMasterChunks; parser->parse != NULL; ++parser) { |
|
if (!memcmp(parser->id, GetBuffer(&dmux->mem_), TAG_SIZE)) { |
|
status = parser->parse(dmux); |
|
if (status == PARSE_OK) dmux->state_ = WEBP_DEMUX_DONE; |
|
if (status == PARSE_NEED_MORE_DATA && !partial) status = PARSE_ERROR; |
|
if (status != PARSE_ERROR && !parser->valid(dmux)) status = PARSE_ERROR; |
|
if (status == PARSE_ERROR) dmux->state_ = WEBP_DEMUX_PARSE_ERROR; |
|
break; |
|
} |
|
} |
|
if (state != NULL) *state = dmux->state_; |
|
|
|
if (status == PARSE_ERROR) { |
|
WebPDemuxDelete(dmux); |
|
return NULL; |
|
} |
|
return dmux; |
|
} |
|
|
|
void WebPDemuxDelete(WebPDemuxer* dmux) { |
|
Chunk* c; |
|
Frame* f; |
|
if (dmux == NULL) return; |
|
|
|
for (f = dmux->frames_; f != NULL;) { |
|
Frame* const cur_frame = f; |
|
f = f->next_; |
|
WebPSafeFree(cur_frame); |
|
} |
|
for (c = dmux->chunks_; c != NULL;) { |
|
Chunk* const cur_chunk = c; |
|
c = c->next_; |
|
WebPSafeFree(cur_chunk); |
|
} |
|
WebPSafeFree(dmux); |
|
} |
|
|
|
// ----------------------------------------------------------------------------- |
|
|
|
uint32_t WebPDemuxGetI(const WebPDemuxer* dmux, WebPFormatFeature feature) { |
|
if (dmux == NULL) return 0; |
|
|
|
switch (feature) { |
|
case WEBP_FF_FORMAT_FLAGS: return dmux->feature_flags_; |
|
case WEBP_FF_CANVAS_WIDTH: return (uint32_t)dmux->canvas_width_; |
|
case WEBP_FF_CANVAS_HEIGHT: return (uint32_t)dmux->canvas_height_; |
|
case WEBP_FF_LOOP_COUNT: return (uint32_t)dmux->loop_count_; |
|
case WEBP_FF_BACKGROUND_COLOR: return dmux->bgcolor_; |
|
case WEBP_FF_FRAME_COUNT: return (uint32_t)dmux->num_frames_; |
|
} |
|
return 0; |
|
} |
|
|
|
// ----------------------------------------------------------------------------- |
|
// Frame iteration |
|
|
|
static const Frame* GetFrame(const WebPDemuxer* const dmux, int frame_num) { |
|
const Frame* f; |
|
for (f = dmux->frames_; f != NULL; f = f->next_) { |
|
if (frame_num == f->frame_num_) break; |
|
} |
|
return f; |
|
} |
|
|
|
static const uint8_t* GetFramePayload(const uint8_t* const mem_buf, |
|
const Frame* const frame, |
|
size_t* const data_size) { |
|
*data_size = 0; |
|
if (frame != NULL) { |
|
const ChunkData* const image = frame->img_components_; |
|
const ChunkData* const alpha = frame->img_components_ + 1; |
|
size_t start_offset = image->offset_; |
|
*data_size = image->size_; |
|
|
|
// if alpha exists it precedes image, update the size allowing for |
|
// intervening chunks. |
|
if (alpha->size_ > 0) { |
|
const size_t inter_size = (image->offset_ > 0) |
|
? image->offset_ - (alpha->offset_ + alpha->size_) |
|
: 0; |
|
start_offset = alpha->offset_; |
|
*data_size += alpha->size_ + inter_size; |
|
} |
|
return mem_buf + start_offset; |
|
} |
|
return NULL; |
|
} |
|
|
|
// Create a whole 'frame' from VP8 (+ alpha) or lossless. |
|
static int SynthesizeFrame(const WebPDemuxer* const dmux, |
|
const Frame* const frame, |
|
WebPIterator* const iter) { |
|
const uint8_t* const mem_buf = dmux->mem_.buf_; |
|
size_t payload_size = 0; |
|
const uint8_t* const payload = GetFramePayload(mem_buf, frame, &payload_size); |
|
if (payload == NULL) return 0; |
|
assert(frame != NULL); |
|
|
|
iter->frame_num = frame->frame_num_; |
|
iter->num_frames = dmux->num_frames_; |
|
iter->x_offset = frame->x_offset_; |
|
iter->y_offset = frame->y_offset_; |
|
iter->width = frame->width_; |
|
iter->height = frame->height_; |
|
iter->has_alpha = frame->has_alpha_; |
|
iter->duration = frame->duration_; |
|
iter->dispose_method = frame->dispose_method_; |
|
iter->blend_method = frame->blend_method_; |
|
iter->complete = frame->complete_; |
|
iter->fragment.bytes = payload; |
|
iter->fragment.size = payload_size; |
|
return 1; |
|
} |
|
|
|
static int SetFrame(int frame_num, WebPIterator* const iter) { |
|
const Frame* frame; |
|
const WebPDemuxer* const dmux = (WebPDemuxer*)iter->private_; |
|
if (dmux == NULL || frame_num < 0) return 0; |
|
if (frame_num > dmux->num_frames_) return 0; |
|
if (frame_num == 0) frame_num = dmux->num_frames_; |
|
|
|
frame = GetFrame(dmux, frame_num); |
|
if (frame == NULL) return 0; |
|
|
|
return SynthesizeFrame(dmux, frame, iter); |
|
} |
|
|
|
int WebPDemuxGetFrame(const WebPDemuxer* dmux, int frame, WebPIterator* iter) { |
|
if (iter == NULL) return 0; |
|
|
|
memset(iter, 0, sizeof(*iter)); |
|
iter->private_ = (void*)dmux; |
|
return SetFrame(frame, iter); |
|
} |
|
|
|
int WebPDemuxNextFrame(WebPIterator* iter) { |
|
if (iter == NULL) return 0; |
|
return SetFrame(iter->frame_num + 1, iter); |
|
} |
|
|
|
int WebPDemuxPrevFrame(WebPIterator* iter) { |
|
if (iter == NULL) return 0; |
|
if (iter->frame_num <= 1) return 0; |
|
return SetFrame(iter->frame_num - 1, iter); |
|
} |
|
|
|
void WebPDemuxReleaseIterator(WebPIterator* iter) { |
|
(void)iter; |
|
} |
|
|
|
// ----------------------------------------------------------------------------- |
|
// Chunk iteration |
|
|
|
static int ChunkCount(const WebPDemuxer* const dmux, const char fourcc[4]) { |
|
const uint8_t* const mem_buf = dmux->mem_.buf_; |
|
const Chunk* c; |
|
int count = 0; |
|
for (c = dmux->chunks_; c != NULL; c = c->next_) { |
|
const uint8_t* const header = mem_buf + c->data_.offset_; |
|
if (!memcmp(header, fourcc, TAG_SIZE)) ++count; |
|
} |
|
return count; |
|
} |
|
|
|
static const Chunk* GetChunk(const WebPDemuxer* const dmux, |
|
const char fourcc[4], int chunk_num) { |
|
const uint8_t* const mem_buf = dmux->mem_.buf_; |
|
const Chunk* c; |
|
int count = 0; |
|
for (c = dmux->chunks_; c != NULL; c = c->next_) { |
|
const uint8_t* const header = mem_buf + c->data_.offset_; |
|
if (!memcmp(header, fourcc, TAG_SIZE)) ++count; |
|
if (count == chunk_num) break; |
|
} |
|
return c; |
|
} |
|
|
|
static int SetChunk(const char fourcc[4], int chunk_num, |
|
WebPChunkIterator* const iter) { |
|
const WebPDemuxer* const dmux = (WebPDemuxer*)iter->private_; |
|
int count; |
|
|
|
if (dmux == NULL || fourcc == NULL || chunk_num < 0) return 0; |
|
count = ChunkCount(dmux, fourcc); |
|
if (count == 0) return 0; |
|
if (chunk_num == 0) chunk_num = count; |
|
|
|
if (chunk_num <= count) { |
|
const uint8_t* const mem_buf = dmux->mem_.buf_; |
|
const Chunk* const chunk = GetChunk(dmux, fourcc, chunk_num); |
|
iter->chunk.bytes = mem_buf + chunk->data_.offset_ + CHUNK_HEADER_SIZE; |
|
iter->chunk.size = chunk->data_.size_ - CHUNK_HEADER_SIZE; |
|
iter->num_chunks = count; |
|
iter->chunk_num = chunk_num; |
|
return 1; |
|
} |
|
return 0; |
|
} |
|
|
|
int WebPDemuxGetChunk(const WebPDemuxer* dmux, |
|
const char fourcc[4], int chunk_num, |
|
WebPChunkIterator* iter) { |
|
if (iter == NULL) return 0; |
|
|
|
memset(iter, 0, sizeof(*iter)); |
|
iter->private_ = (void*)dmux; |
|
return SetChunk(fourcc, chunk_num, iter); |
|
} |
|
|
|
int WebPDemuxNextChunk(WebPChunkIterator* iter) { |
|
if (iter != NULL) { |
|
const char* const fourcc = |
|
(const char*)iter->chunk.bytes - CHUNK_HEADER_SIZE; |
|
return SetChunk(fourcc, iter->chunk_num + 1, iter); |
|
} |
|
return 0; |
|
} |
|
|
|
int WebPDemuxPrevChunk(WebPChunkIterator* iter) { |
|
if (iter != NULL && iter->chunk_num > 1) { |
|
const char* const fourcc = |
|
(const char*)iter->chunk.bytes - CHUNK_HEADER_SIZE; |
|
return SetChunk(fourcc, iter->chunk_num - 1, iter); |
|
} |
|
return 0; |
|
} |
|
|
|
void WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter) { |
|
(void)iter; |
|
} |
|
|
|
|