diff options
Diffstat (limited to 'drivers/webp/mux/demux.c')
| -rw-r--r-- | drivers/webp/mux/demux.c | 902 |
1 files changed, 902 insertions, 0 deletions
diff --git a/drivers/webp/mux/demux.c b/drivers/webp/mux/demux.c new file mode 100644 index 0000000000..4519f7d55b --- /dev/null +++ b/drivers/webp/mux/demux.c @@ -0,0 +1,902 @@ +// Copyright 2012 Google Inc. All Rights Reserved. +// +// This code is licensed under the same terms as WebM: +// Software License Agreement: http://www.webmproject.org/license/software/ +// Additional IP Rights Grant: http://www.webmproject.org/license/additional/ +// ----------------------------------------------------------------------------- +// +// WebP container demux. +// + +#include "../webp/mux.h" + +#include <stdlib.h> +#include <string.h> + +#include "../webp/decode.h" // WebPGetInfo +#include "../webp/format_constants.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +#define MKFOURCC(a, b, c, d) ((uint32_t)(a) | (b) << 8 | (c) << 16 | (d) << 24) + +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 duration_; + int is_tile_; // this is an image fragment from a 'TILE'. + int frame_num_; // the referent frame number for use in assembling tiles. + 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_; + int num_frames_; + Frame* frames_; + Chunk* chunks_; // non-image chunks +}; + +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 }, +}; + +// ----------------------------------------------------------------------------- +// 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_; +} + +static WEBP_INLINE uint8_t GetByte(MemBuffer* const mem) { + const uint8_t byte = mem->buf_[mem->start_]; + Skip(mem, 1); + return byte; +} + +// Read 16, 24 or 32 bits stored in little-endian order. +static WEBP_INLINE int ReadLE16s(const uint8_t* const data) { + return (int)(data[0] << 0) | (data[1] << 8); +} + +static WEBP_INLINE int ReadLE24s(const uint8_t* const data) { + return ReadLE16s(data) | (data[2] << 16); +} + +static WEBP_INLINE uint32_t ReadLE32(const uint8_t* const data) { + return (uint32_t)ReadLE24s(data) | (data[3] << 24); +} + +// In addition to reading, skip the read bytes. +static WEBP_INLINE int GetLE16s(MemBuffer* const mem) { + const uint8_t* const data = mem->buf_ + mem->start_; + const int val = ReadLE16s(data); + Skip(mem, 2); + return val; +} + +static WEBP_INLINE int GetLE24s(MemBuffer* const mem) { + const uint8_t* const data = mem->buf_ + mem->start_; + const int val = ReadLE24s(data); + Skip(mem, 3); + return val; +} + +static WEBP_INLINE uint32_t GetLE32(MemBuffer* const mem) { + const uint8_t* const data = mem->buf_ + mem->start_; + const uint32_t val = ReadLE32(data); + Skip(mem, 4); + return val; +} + +// ----------------------------------------------------------------------------- +// Secondary chunk parsing + +static void AddChunk(WebPDemuxer* const dmux, Chunk* const chunk) { + Chunk** c = &dmux->chunks_; + while (*c != NULL) c = &(*c)->next_; + *c = chunk; + chunk->next_ = NULL; +} + +// 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* last_frame = NULL; + Frame** f = &dmux->frames_; + while (*f != NULL) { + last_frame = *f; + f = &(*f)->next_; + } + if (last_frame != NULL && !last_frame->complete_) return 0; + *f = frame; + frame->next_ = NULL; + return 1; +} + +// Store image bearing chunks to 'frame'. +static ParseStatus StoreFrame(int frame_num, MemBuffer* const mem, + Frame* const frame) { + int alpha_chunks = 0; + int image_chunks = 0; + int done = (MemDataSize(mem) < CHUNK_HEADER_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 = GetLE32(mem); + const uint32_t payload_size = GetLE32(mem); + const uint32_t payload_size_padded = payload_size + (payload_size & 1); + const size_t payload_available = (payload_size_padded > MemDataSize(mem)) + ? MemDataSize(mem) : payload_size_padded; + const size_t chunk_size = CHUNK_HEADER_SIZE + payload_available; + + if (payload_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; + 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->frame_num_ = frame_num; + Skip(mem, payload_available); + } else { + goto Done; + } + break; + case MKFOURCC('V', 'P', '8', ' '): + case MKFOURCC('V', 'P', '8', 'L'): + if (image_chunks == 0) { + int width = 0, height = 0; + ++image_chunks; + frame->img_components_[0].offset_ = chunk_start_offset; + frame->img_components_[0].size_ = chunk_size; + // Extract the width and height from the bitstream, tolerating + // failures when the data is incomplete. + if (!WebPGetInfo(mem->buf_ + frame->img_components_[0].offset_, + frame->img_components_[0].size_, &width, &height) && + status != PARSE_NEED_MORE_DATA) { + return PARSE_ERROR; + } + + frame->width_ = width; + frame->height_ = height; + frame->frame_num_ = frame_num; + frame->complete_ = (status == PARSE_OK); + 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 expected_size, + uint32_t actual_size, Frame** frame) { + if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR; + if (actual_size < expected_size) return PARSE_ERROR; + if (MemDataSize(mem) < min_size) return PARSE_NEED_MORE_DATA; + + *frame = (Frame*)calloc(1, sizeof(**frame)); + return (*frame == NULL) ? PARSE_ERROR : PARSE_OK; +} + +// Parse a 'FRM ' chunk and any image bearing chunks that immediately follow. +// 'frame_chunk_size' is the previously validated, padded chunk size. +static ParseStatus ParseFrame( + WebPDemuxer* const dmux, uint32_t frame_chunk_size) { + const int has_frames = !!(dmux->feature_flags_ & ANIMATION_FLAG); + const uint32_t min_size = frame_chunk_size + CHUNK_HEADER_SIZE; + int added_frame = 0; + MemBuffer* const mem = &dmux->mem_; + Frame* frame; + ParseStatus status = + NewFrame(mem, min_size, FRAME_CHUNK_SIZE, frame_chunk_size, &frame); + if (status != PARSE_OK) return status; + + frame->x_offset_ = 2 * GetLE24s(mem); + frame->y_offset_ = 2 * GetLE24s(mem); + frame->width_ = 1 + GetLE24s(mem); + frame->height_ = 1 + GetLE24s(mem); + frame->duration_ = 1 + GetLE24s(mem); + Skip(mem, frame_chunk_size - FRAME_CHUNK_SIZE); // skip any trailing data. + if (frame->width_ * (uint64_t)frame->height_ >= MAX_IMAGE_AREA) { + return PARSE_ERROR; + } + + // Store a (potentially partial) frame only if the animation flag is set + // and there is some data in 'frame'. + status = StoreFrame(dmux->num_frames_ + 1, mem, frame); + if (status != PARSE_ERROR && has_frames && frame->frame_num_ > 0) { + added_frame = AddFrame(dmux, frame); + if (added_frame) { + ++dmux->num_frames_; + } else { + status = PARSE_ERROR; + } + } + + if (!added_frame) free(frame); + return status; +} + +// Parse a 'TILE' chunk and any image bearing chunks that immediately follow. +// 'tile_chunk_size' is the previously validated, padded chunk size. +static ParseStatus ParseTile(WebPDemuxer* const dmux, + uint32_t tile_chunk_size) { + const int has_tiles = !!(dmux->feature_flags_ & TILE_FLAG); + const uint32_t min_size = tile_chunk_size + CHUNK_HEADER_SIZE; + int added_tile = 0; + MemBuffer* const mem = &dmux->mem_; + Frame* frame; + ParseStatus status = + NewFrame(mem, min_size, TILE_CHUNK_SIZE, tile_chunk_size, &frame); + if (status != PARSE_OK) return status; + + frame->is_tile_ = 1; + frame->x_offset_ = 2 * GetLE24s(mem); + frame->y_offset_ = 2 * GetLE24s(mem); + Skip(mem, tile_chunk_size - TILE_CHUNK_SIZE); // skip any trailing data. + + // Store a (potentially partial) tile only if the tile flag is set + // and the tile contains some data. + status = StoreFrame(dmux->num_frames_, mem, frame); + if (status != PARSE_ERROR && has_tiles && frame->frame_num_ > 0) { + // Note num_frames_ is incremented only when all tiles have been consumed. + added_tile = AddFrame(dmux, frame); + if (!added_tile) status = PARSE_ERROR; + } + + if (!added_tile) free(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*)calloc(1, 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 int 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 0; + if (memcmp(GetBuffer(mem), "RIFF", CHUNK_SIZE_BYTES) || + memcmp(GetBuffer(mem) + CHUNK_HEADER_SIZE, "WEBP", CHUNK_SIZE_BYTES)) { + return 0; + } + + riff_size = ReadLE32(GetBuffer(mem) + TAG_SIZE); + if (riff_size < CHUNK_HEADER_SIZE) return 0; + if (riff_size > MAX_CHUNK_PAYLOAD) return 0; + + // 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 1; +} + +static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) { + const size_t min_size = CHUNK_HEADER_SIZE; + MemBuffer* const mem = &dmux->mem_; + Frame* frame; + ParseStatus status; + + 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*)calloc(1, sizeof(*frame)); + if (frame == NULL) return PARSE_ERROR; + + status = StoreFrame(1, &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; + } + + // Use the frame width/height as the canvas values for non-vp8x files. + 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_; + } + AddFrame(dmux, frame); + dmux->num_frames_ = 1; + } else { + free(frame); + } + + return status; +} + +static ParseStatus ParseVP8X(WebPDemuxer* const dmux) { + MemBuffer* const mem = &dmux->mem_; + int loop_chunks = 0; + uint32_t vp8x_size; + ParseStatus status = PARSE_OK; + + if (MemDataSize(mem) < CHUNK_HEADER_SIZE) return PARSE_NEED_MORE_DATA; + + dmux->is_ext_format_ = 1; + Skip(mem, TAG_SIZE); // VP8X + vp8x_size = GetLE32(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_ = GetByte(mem); + Skip(mem, 3); // Reserved. + dmux->canvas_width_ = 1 + GetLE24s(mem); + dmux->canvas_height_ = 1 + GetLE24s(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; + + do { + int store_chunk = 1; + const size_t chunk_start_offset = mem->start_; + const uint32_t fourcc = GetLE32(mem); + const uint32_t chunk_size = GetLE32(mem); + const uint32_t chunk_size_padded = chunk_size + (chunk_size & 1); + + if (chunk_size > MAX_CHUNK_PAYLOAD) return PARSE_ERROR; + 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'): { + Rewind(mem, CHUNK_HEADER_SIZE); + status = ParseSingleImage(dmux); + break; + } + case MKFOURCC('L', 'O', 'O', 'P'): { + if (chunk_size_padded < LOOP_CHUNK_SIZE) return PARSE_ERROR; + + if (MemDataSize(mem) < chunk_size_padded) { + status = PARSE_NEED_MORE_DATA; + } else if (loop_chunks == 0) { + ++loop_chunks; + dmux->loop_count_ = GetLE16s(mem); + Skip(mem, chunk_size_padded - LOOP_CHUNK_SIZE); + } else { + store_chunk = 0; + goto Skip; + } + break; + } + case MKFOURCC('F', 'R', 'M', ' '): { + status = ParseFrame(dmux, chunk_size_padded); + break; + } + case MKFOURCC('T', 'I', 'L', 'E'): { + if (dmux->num_frames_ == 0) dmux->num_frames_ = 1; + status = ParseTile(dmux, chunk_size_padded); + break; + } + case MKFOURCC('I', 'C', 'C', 'P'): { + store_chunk = !!(dmux->feature_flags_ & ICCP_FLAG); + goto Skip; + } + case MKFOURCC('M', 'E', 'T', 'A'): { + store_chunk = !!(dmux->feature_flags_ & META_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; +} + +// ----------------------------------------------------------------------------- +// 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; +} + +static int IsValidExtendedFormat(const WebPDemuxer* const dmux) { + const int has_tiles = !!(dmux->feature_flags_ & TILE_FLAG); + const int has_frames = !!(dmux->feature_flags_ & ANIMATION_FLAG); + const Frame* f; + + 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; + + for (f = dmux->frames_; f != NULL; f = f->next_) { + const int cur_frame_set = f->frame_num_; + int frame_count = 0, tile_count = 0; + + // Check frame properties and if the image is composed of tiles that each + // fragment came from a 'TILE'. + 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 (!has_tiles && f->is_tile_) return 0; + if (!has_frames && f->frame_num_ > 1) return 0; + if (f->x_offset_ < 0 || f->y_offset_ < 0) 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 { + // 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; + } + + tile_count += f->is_tile_; + ++frame_count; + } + if (!has_tiles && frame_count > 1) return 0; + if (tile_count > 0 && frame_count != tile_count) return 0; + if (f == NULL) break; + } + 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->canvas_width_ = -1; + dmux->canvas_height_ = -1; + dmux->mem_ = *mem; +} + +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 (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; + if (!ReadHeader(&mem)) return NULL; + + partial = (mem.buf_size_ < mem.riff_end_); + if (!allow_partial && partial) return NULL; + + dmux = (WebPDemuxer*)calloc(1, sizeof(*dmux)); + if (dmux == NULL) return NULL; + InitDemux(dmux, &mem); + + 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_ERROR && !parser->valid(dmux)) status = PARSE_ERROR; + break; + } + } + if (state) *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_; + free(cur_frame); + } + for (c = dmux->chunks_; c != NULL;) { + Chunk* const cur_chunk = c; + c = c->next_; + free(cur_chunk); + } + free(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_; + } + return 0; +} + +// ----------------------------------------------------------------------------- +// Frame iteration + +// Find the first 'frame_num' frame. There may be multiple in a tiled frame. +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; +} + +// Returns tile 'tile_num' and the total count. +static const Frame* GetTile( + const Frame* const frame_set, int tile_num, int* const count) { + const int this_frame = frame_set->frame_num_; + const Frame* f = frame_set; + const Frame* tile = NULL; + int total; + + for (total = 0; f != NULL && f->frame_num_ == this_frame; f = f->next_) { + if (++total == tile_num) tile = f; + } + *count = total; + return tile; +} + +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 first_frame, + int tile_num, WebPIterator* const iter) { + const uint8_t* const mem_buf = dmux->mem_.buf_; + int num_tiles; + size_t payload_size = 0; + const Frame* const tile = GetTile(first_frame, tile_num, &num_tiles); + const uint8_t* const payload = GetFramePayload(mem_buf, tile, &payload_size); + if (payload == NULL) return 0; + + iter->frame_num_ = first_frame->frame_num_; + iter->num_frames_ = dmux->num_frames_; + iter->tile_num_ = tile_num; + iter->num_tiles_ = num_tiles; + iter->x_offset_ = tile->x_offset_; + iter->y_offset_ = tile->y_offset_; + iter->width_ = tile->width_; + iter->height_ = tile->height_; + iter->duration_ = tile->duration_; + iter->complete_ = tile->complete_; + iter->tile_.bytes_ = payload; + iter->tile_.size_ = payload_size; + // TODO(jzern): adjust offsets for 'TILE's embedded in 'FRM 's + 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); + return SynthesizeFrame(dmux, frame, 1, 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); +} + +int WebPDemuxSelectTile(WebPIterator* iter, int tile) { + if (iter != NULL && iter->private_ != NULL && tile > 0) { + const WebPDemuxer* const dmux = (WebPDemuxer*)iter->private_; + const Frame* const frame = GetFrame(dmux, iter->frame_num_); + if (frame == NULL) return 0; + + return SynthesizeFrame(dmux, frame, tile, iter); + } + return 0; +} + +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; +} + +#if defined(__cplusplus) || defined(c_plusplus) +} // extern "C" +#endif |