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-rw-r--r--media/libwebp/src/demux/demux.c975
1 files changed, 975 insertions, 0 deletions
diff --git a/media/libwebp/src/demux/demux.c b/media/libwebp/src/demux/demux.c
new file mode 100644
index 0000000000..324e5eb993
--- /dev/null
+++ b/media/libwebp/src/demux/demux.c
@@ -0,0 +1,975 @@
+// Copyright 2012 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.
+// -----------------------------------------------------------------------------
+//
+// WebP container demux.
+//
+
+#ifdef HAVE_CONFIG_H
+#include "src/webp/config.h"
+#endif
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "src/utils/utils.h"
+#include "src/webp/decode.h" // WebPGetFeatures
+#include "src/webp/demux.h"
+#include "src/webp/format_constants.h"
+
+#define DMUX_MAJ_VERSION 1
+#define DMUX_MIN_VERSION 3
+#define DMUX_REV_VERSION 0
+
+typedef struct {
+ size_t start_; // start location of the data
+ size_t end_; // end location
+ size_t riff_end_; // riff chunk end location, can be > end_.
+ size_t buf_size_; // size of the buffer
+ const uint8_t* buf_;
+} MemBuffer;
+
+typedef struct {
+ size_t offset_;
+ size_t size_;
+} ChunkData;
+
+typedef struct Frame {
+ int x_offset_, y_offset_;
+ int width_, height_;
+ int has_alpha_;
+ int duration_;
+ WebPMuxAnimDispose dispose_method_;
+ WebPMuxAnimBlend blend_method_;
+ int frame_num_;
+ int complete_; // img_components_ contains a full image.
+ ChunkData img_components_[2]; // 0=VP8{,L} 1=ALPH
+ struct Frame* next_;
+} Frame;
+
+typedef struct Chunk {
+ ChunkData data_;
+ struct Chunk* next_;
+} Chunk;
+
+struct WebPDemuxer {
+ MemBuffer mem_;
+ WebPDemuxState state_;
+ int is_ext_format_;
+ uint32_t feature_flags_;
+ int canvas_width_, canvas_height_;
+ int loop_count_;
+ uint32_t bgcolor_;
+ int num_frames_;
+ Frame* frames_;
+ Frame** frames_tail_;
+ Chunk* chunks_; // non-image chunks
+ Chunk** chunks_tail_;
+};
+
+typedef enum {
+ PARSE_OK,
+ PARSE_NEED_MORE_DATA,
+ PARSE_ERROR
+} ParseStatus;
+
+typedef struct ChunkParser {
+ uint8_t id[4];
+ ParseStatus (*parse)(WebPDemuxer* const dmux);
+ int (*valid)(const WebPDemuxer* const dmux);
+} ChunkParser;
+
+static ParseStatus ParseSingleImage(WebPDemuxer* const dmux);
+static ParseStatus ParseVP8X(WebPDemuxer* const dmux);
+static int IsValidSimpleFormat(const WebPDemuxer* const dmux);
+static int IsValidExtendedFormat(const WebPDemuxer* const dmux);
+
+static const ChunkParser kMasterChunks[] = {
+ { { 'V', 'P', '8', ' ' }, ParseSingleImage, IsValidSimpleFormat },
+ { { 'V', 'P', '8', 'L' }, ParseSingleImage, IsValidSimpleFormat },
+ { { 'V', 'P', '8', 'X' }, ParseVP8X, IsValidExtendedFormat },
+ { { '0', '0', '0', '0' }, NULL, NULL },
+};
+
+//------------------------------------------------------------------------------
+
+int WebPGetDemuxVersion(void) {
+ return (DMUX_MAJ_VERSION << 16) | (DMUX_MIN_VERSION << 8) | DMUX_REV_VERSION;
+}
+
+// -----------------------------------------------------------------------------
+// MemBuffer
+
+static int RemapMemBuffer(MemBuffer* const mem,
+ const uint8_t* data, size_t size) {
+ if (size < mem->buf_size_) return 0; // can't remap to a shorter buffer!
+
+ mem->buf_ = data;
+ mem->end_ = mem->buf_size_ = size;
+ return 1;
+}
+
+static int InitMemBuffer(MemBuffer* const mem,
+ const uint8_t* data, size_t size) {
+ memset(mem, 0, sizeof(*mem));
+ return RemapMemBuffer(mem, data, size);
+}
+
+// Return the remaining data size available in 'mem'.
+static WEBP_INLINE size_t MemDataSize(const MemBuffer* const mem) {
+ return (mem->end_ - mem->start_);
+}
+
+// Return true if 'size' exceeds the end of the RIFF chunk.
+static WEBP_INLINE int SizeIsInvalid(const MemBuffer* const mem, size_t size) {
+ return (size > mem->riff_end_ - mem->start_);
+}
+
+static WEBP_INLINE void Skip(MemBuffer* const mem, size_t size) {
+ mem->start_ += size;
+}
+
+static WEBP_INLINE void Rewind(MemBuffer* const mem, size_t size) {
+ mem->start_ -= size;
+}
+
+static WEBP_INLINE const uint8_t* GetBuffer(MemBuffer* const mem) {
+ return mem->buf_ + mem->start_;
+}
+
+// Read from 'mem' and skip the read bytes.
+static WEBP_INLINE uint8_t ReadByte(MemBuffer* const mem) {
+ const uint8_t byte = mem->buf_[mem->start_];
+ Skip(mem, 1);
+ return byte;
+}
+
+static WEBP_INLINE int ReadLE16s(MemBuffer* const mem) {
+ const uint8_t* const data = mem->buf_ + mem->start_;
+ const int val = GetLE16(data);
+ Skip(mem, 2);
+ return val;
+}
+
+static WEBP_INLINE int ReadLE24s(MemBuffer* const mem) {
+ const uint8_t* const data = mem->buf_ + mem->start_;
+ const int val = GetLE24(data);
+ Skip(mem, 3);
+ return val;
+}
+
+static WEBP_INLINE uint32_t ReadLE32(MemBuffer* const mem) {
+ const uint8_t* const data = mem->buf_ + mem->start_;
+ const uint32_t val = GetLE32(data);
+ Skip(mem, 4);
+ return val;
+}
+
+// -----------------------------------------------------------------------------
+// Secondary chunk parsing
+
+static void AddChunk(WebPDemuxer* const dmux, Chunk* const chunk) {
+ *dmux->chunks_tail_ = chunk;
+ chunk->next_ = NULL;
+ dmux->chunks_tail_ = &chunk->next_;
+}
+
+// Add a frame to the end of the list, ensuring the last frame is complete.
+// Returns true on success, false otherwise.
+static int AddFrame(WebPDemuxer* const dmux, Frame* const frame) {
+ const Frame* const last_frame = *dmux->frames_tail_;
+ if (last_frame != NULL && !last_frame->complete_) return 0;
+
+ *dmux->frames_tail_ = frame;
+ frame->next_ = NULL;
+ dmux->frames_tail_ = &frame->next_;
+ return 1;
+}
+
+static void SetFrameInfo(size_t start_offset, size_t size,
+ int frame_num, int complete,
+ const WebPBitstreamFeatures* const features,
+ Frame* const frame) {
+ frame->img_components_[0].offset_ = start_offset;
+ frame->img_components_[0].size_ = size;
+ frame->width_ = features->width;
+ frame->height_ = features->height;
+ frame->has_alpha_ |= features->has_alpha;
+ frame->frame_num_ = frame_num;
+ frame->complete_ = complete;
+}
+
+// Store image bearing chunks to 'frame'. 'min_size' is an optional size
+// requirement, it may be zero.
+static ParseStatus StoreFrame(int frame_num, uint32_t min_size,
+ MemBuffer* const mem, Frame* const frame) {
+ int alpha_chunks = 0;
+ int image_chunks = 0;
+ int done = (MemDataSize(mem) < CHUNK_HEADER_SIZE ||
+ MemDataSize(mem) < min_size);
+ ParseStatus status = PARSE_OK;
+
+ if (done) return PARSE_NEED_MORE_DATA;
+
+ do {
+ const size_t chunk_start_offset = mem->start_;
+ const uint32_t fourcc = ReadLE32(mem);
+ const uint32_t payload_size = ReadLE32(mem);
+ uint32_t payload_size_padded;
+ size_t payload_available;
+ size_t chunk_size;
+
+ if (payload_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR;
+
+ payload_size_padded = payload_size + (payload_size & 1);
+ payload_available = (payload_size_padded > MemDataSize(mem))
+ ? MemDataSize(mem) : payload_size_padded;
+ chunk_size = CHUNK_HEADER_SIZE + payload_available;
+ if (SizeIsInvalid(mem, payload_size_padded)) return PARSE_ERROR;
+ if (payload_size_padded > MemDataSize(mem)) status = PARSE_NEED_MORE_DATA;
+
+ switch (fourcc) {
+ case MKFOURCC('A', 'L', 'P', 'H'):
+ if (alpha_chunks == 0) {
+ ++alpha_chunks;
+ frame->img_components_[1].offset_ = chunk_start_offset;
+ frame->img_components_[1].size_ = chunk_size;
+ frame->has_alpha_ = 1;
+ frame->frame_num_ = frame_num;
+ Skip(mem, payload_available);
+ } else {
+ goto Done;
+ }
+ break;
+ case MKFOURCC('V', 'P', '8', 'L'):
+ if (alpha_chunks > 0) return PARSE_ERROR; // VP8L has its own alpha
+ // fall through
+ case MKFOURCC('V', 'P', '8', ' '):
+ if (image_chunks == 0) {
+ // Extract the bitstream features, tolerating failures when the data
+ // is incomplete.
+ WebPBitstreamFeatures features;
+ const VP8StatusCode vp8_status =
+ WebPGetFeatures(mem->buf_ + chunk_start_offset, chunk_size,
+ &features);
+ if (status == PARSE_NEED_MORE_DATA &&
+ vp8_status == VP8_STATUS_NOT_ENOUGH_DATA) {
+ return PARSE_NEED_MORE_DATA;
+ } else if (vp8_status != VP8_STATUS_OK) {
+ // We have enough data, and yet WebPGetFeatures() failed.
+ return PARSE_ERROR;
+ }
+ ++image_chunks;
+ SetFrameInfo(chunk_start_offset, chunk_size, frame_num,
+ status == PARSE_OK, &features, frame);
+ Skip(mem, payload_available);
+ } else {
+ goto Done;
+ }
+ break;
+ Done:
+ default:
+ // Restore fourcc/size when moving up one level in parsing.
+ Rewind(mem, CHUNK_HEADER_SIZE);
+ done = 1;
+ break;
+ }
+
+ if (mem->start_ == mem->riff_end_) {
+ done = 1;
+ } else if (MemDataSize(mem) < CHUNK_HEADER_SIZE) {
+ status = PARSE_NEED_MORE_DATA;
+ }
+ } while (!done && status == PARSE_OK);
+
+ return status;
+}
+
+// Creates a new Frame if 'actual_size' is within bounds and 'mem' contains
+// enough data ('min_size') to parse the payload.
+// Returns PARSE_OK on success with *frame pointing to the new Frame.
+// Returns PARSE_NEED_MORE_DATA with insufficient data, PARSE_ERROR otherwise.
+static ParseStatus NewFrame(const MemBuffer* const mem,
+ uint32_t min_size, uint32_t actual_size,
+ Frame** frame) {
+ if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR;
+ if (actual_size < min_size) return PARSE_ERROR;
+ if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA;
+
+ *frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(**frame));
+ return (*frame == NULL) ? PARSE_ERROR : PARSE_OK;
+}
+
+// Parse a 'ANMF' chunk and any image bearing chunks that immediately follow.
+// 'frame_chunk_size' is the previously validated, padded chunk size.
+static ParseStatus ParseAnimationFrame(
+ WebPDemuxer* const dmux, uint32_t frame_chunk_size) {
+ const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG);
+ const uint32_t anmf_payload_size = frame_chunk_size - ANMF_CHUNK_SIZE;
+ int added_frame = 0;
+ int bits;
+ MemBuffer* const mem = &dmux->mem_;
+ Frame* frame;
+ size_t start_offset;
+ ParseStatus status =
+ NewFrame(mem, ANMF_CHUNK_SIZE, frame_chunk_size, &frame);
+ if (status != PARSE_OK) return status;
+
+ frame->x_offset_ = 2 * ReadLE24s(mem);
+ frame->y_offset_ = 2 * ReadLE24s(mem);
+ frame->width_ = 1 + ReadLE24s(mem);
+ frame->height_ = 1 + ReadLE24s(mem);
+ frame->duration_ = ReadLE24s(mem);
+ bits = ReadByte(mem);
+ 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;
+ if (frame->width_ * (uint64_t)frame->height_ >= MAX_IMAGE_AREA) {
+ WebPSafeFree(frame);
+ return PARSE_ERROR;
+ }
+
+ // Store a frame only if the animation flag is set there is some data for
+ // this frame is available.
+ start_offset = mem->start_;
+ status = StoreFrame(dmux->num_frames_ + 1, anmf_payload_size, mem, frame);
+ if (status != PARSE_ERROR && mem->start_ - start_offset > anmf_payload_size) {
+ status = PARSE_ERROR;
+ }
+ if (status != PARSE_ERROR && is_animation && frame->frame_num_ > 0) {
+ added_frame = AddFrame(dmux, frame);
+ if (added_frame) {
+ ++dmux->num_frames_;
+ } else {
+ status = PARSE_ERROR;
+ }
+ }
+
+ if (!added_frame) WebPSafeFree(frame);
+ return status;
+}
+
+// General chunk storage, starting with the header at 'start_offset', allowing
+// the user to request the payload via a fourcc string. 'size' includes the
+// header and the unpadded payload size.
+// Returns true on success, false otherwise.
+static int StoreChunk(WebPDemuxer* const dmux,
+ size_t start_offset, uint32_t size) {
+ Chunk* const chunk = (Chunk*)WebPSafeCalloc(1ULL, sizeof(*chunk));
+ if (chunk == NULL) return 0;
+
+ chunk->data_.offset_ = start_offset;
+ chunk->data_.size_ = size;
+ AddChunk(dmux, chunk);
+ return 1;
+}
+
+// -----------------------------------------------------------------------------
+// Primary chunk parsing
+
+static ParseStatus ReadHeader(MemBuffer* const mem) {
+ const size_t min_size = RIFF_HEADER_SIZE + CHUNK_HEADER_SIZE;
+ uint32_t riff_size;
+
+ // Basic file level validation.
+ if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA;
+ if (memcmp(GetBuffer(mem), "RIFF", CHUNK_SIZE_BYTES) ||
+ memcmp(GetBuffer(mem) + CHUNK_HEADER_SIZE, "WEBP", CHUNK_SIZE_BYTES)) {
+ return PARSE_ERROR;
+ }
+
+ riff_size = GetLE32(GetBuffer(mem) + TAG_SIZE);
+ if (riff_size < CHUNK_HEADER_SIZE) return PARSE_ERROR;
+ if (riff_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR;
+
+ // There's no point in reading past the end of the RIFF chunk
+ mem->riff_end_ = riff_size + CHUNK_HEADER_SIZE;
+ if (mem->buf_size_ > mem->riff_end_) {
+ mem->buf_size_ = mem->end_ = mem->riff_end_;
+ }
+
+ Skip(mem, RIFF_HEADER_SIZE);
+ return PARSE_OK;
+}
+
+static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
+ const size_t min_size = CHUNK_HEADER_SIZE;
+ MemBuffer* const mem = &dmux->mem_;
+ Frame* frame;
+ ParseStatus status;
+ int image_added = 0;
+
+ if (dmux->frames_ != NULL) return PARSE_ERROR;
+ if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR;
+ if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA;
+
+ frame = (Frame*)WebPSafeCalloc(1ULL, sizeof(*frame));
+ if (frame == NULL) return PARSE_ERROR;
+
+ // For the single image case we allow parsing of a partial frame, so no
+ // minimum size is imposed here.
+ status = StoreFrame(1, 0, &dmux->mem_, frame);
+ if (status != PARSE_ERROR) {
+ const int has_alpha = !!(dmux->feature_flags_ & ALPHA_FLAG);
+ // Clear any alpha when the alpha flag is missing.
+ if (!has_alpha && frame->img_components_[1].size_ > 0) {
+ frame->img_components_[1].offset_ = 0;
+ frame->img_components_[1].size_ = 0;
+ frame->has_alpha_ = 0;
+ }
+
+ // Use the frame width/height as the canvas values for non-vp8x files.
+ // Also, set ALPHA_FLAG if this is a lossless image with alpha.
+ if (!dmux->is_ext_format_ && frame->width_ > 0 && frame->height_ > 0) {
+ dmux->state_ = WEBP_DEMUX_PARSED_HEADER;
+ dmux->canvas_width_ = frame->width_;
+ dmux->canvas_height_ = frame->height_;
+ dmux->feature_flags_ |= frame->has_alpha_ ? ALPHA_FLAG : 0;
+ }
+ if (!AddFrame(dmux, frame)) {
+ status = PARSE_ERROR; // last frame was left incomplete
+ } else {
+ image_added = 1;
+ dmux->num_frames_ = 1;
+ }
+ }
+
+ if (!image_added) WebPSafeFree(frame);
+ return status;
+}
+
+static ParseStatus ParseVP8XChunks(WebPDemuxer* const dmux) {
+ const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG);
+ MemBuffer* const mem = &dmux->mem_;
+ int anim_chunks = 0;
+ ParseStatus status = PARSE_OK;
+
+ do {
+ int store_chunk = 1;
+ const size_t chunk_start_offset = mem->start_;
+ const uint32_t fourcc = ReadLE32(mem);
+ const uint32_t chunk_size = ReadLE32(mem);
+ uint32_t chunk_size_padded;
+
+ if (chunk_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR;
+
+ chunk_size_padded = chunk_size + (chunk_size & 1);
+ if (SizeIsInvalid(mem, chunk_size_padded)) return PARSE_ERROR;
+
+ switch (fourcc) {
+ case MKFOURCC('V', 'P', '8', 'X'): {
+ return PARSE_ERROR;
+ }
+ case MKFOURCC('A', 'L', 'P', 'H'):
+ case MKFOURCC('V', 'P', '8', ' '):
+ case MKFOURCC('V', 'P', '8', 'L'): {
+ // check that this isn't an animation (all frames should be in an ANMF).
+ if (anim_chunks > 0 || is_animation) return PARSE_ERROR;
+
+ Rewind(mem, CHUNK_HEADER_SIZE);
+ status = ParseSingleImage(dmux);
+ break;
+ }
+ 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;
+ dmux->bgcolor_ = ReadLE32(mem);
+ dmux->loop_count_ = ReadLE16s(mem);
+ 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'): {
+ store_chunk = !!(dmux->feature_flags_ & ICCP_FLAG);
+ goto Skip;
+ }
+ case MKFOURCC('E', 'X', 'I', 'F'): {
+ store_chunk = !!(dmux->feature_flags_ & EXIF_FLAG);
+ goto Skip;
+ }
+ case MKFOURCC('X', 'M', 'P', ' '): {
+ store_chunk = !!(dmux->feature_flags_ & XMP_FLAG);
+ goto Skip;
+ }
+ 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,
+ 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;
+ } 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_;
+
+ // 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;
+ }
+ }
+ }
+ 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;
+}
+