Merge changes I1d97a633,I81c59093

* changes:
  libwebp/demux: add WebPDemuxGetI
  libwebp/demux: add extended format parsing
This commit is contained in:
pascal massimino 2012-06-13 00:28:25 -07:00 committed by Gerrit Code Review
commit d0601b0107
2 changed files with 359 additions and 14 deletions

View File

@ -36,19 +36,31 @@ typedef struct {
} 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 {
@ -63,13 +75,16 @@ typedef struct ChunkParser {
int (*valid)(const WebPDemuxer* const dmux);
} ChunkParser;
static int IsValidSimpleFormat(const WebPDemuxer* const dmux);
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 },
{ { '0', '0', '0', '0' }, NULL, NULL },
{ { 'V', 'P', '8', 'X' }, ParseVP8X, IsValidExtendedFormat },
{ { '0', '0', '0', '0' }, NULL, NULL },
};
// -----------------------------------------------------------------------------
@ -112,6 +127,12 @@ 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;
}
static WEBP_INLINE uint32_t ReadLE32(const uint8_t* const data) {
return (uint32_t)(data[0] << 0 | (data[1] << 8) |
(data[2] << 16) | (data[3] << 24));
@ -124,9 +145,20 @@ static WEBP_INLINE uint32_t GetLE32(MemBuffer* const mem) {
return val;
}
static WEBP_INLINE int GetLE32s(MemBuffer* const mem) {
return (int)GetLE32(mem);
}
// -----------------------------------------------------------------------------
// 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) {
@ -145,6 +177,7 @@ static int AddFrame(WebPDemuxer* const dmux, Frame* const frame) {
// 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;
@ -165,6 +198,17 @@ static ParseStatus StoreFrame(int frame_num, MemBuffer* const mem,
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) {
@ -207,6 +251,103 @@ static ParseStatus StoreFrame(int frame_num, MemBuffer* const mem,
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 size_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_ = GetLE32s(mem);
frame->y_offset_ = GetLE32s(mem);
frame->width_ = GetLE32s(mem);
frame->height_ = GetLE32s(mem);
frame->duration_ = GetLE32s(mem);
Skip(mem, frame_chunk_size - FRAME_CHUNK_SIZE); // skip any trailing data.
// 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 size_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_ = GetLE32s(mem);
frame->y_offset_ = GetLE32s(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
@ -235,17 +376,6 @@ static int ReadHeader(MemBuffer* const mem) {
return 1;
}
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 ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
const size_t min_size = CHUNK_HEADER_SIZE;
MemBuffer* const mem = &dmux->mem_;
@ -253,6 +383,7 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
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));
@ -260,8 +391,15 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
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_) {
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 (frame->width_ > 0 && frame->height_ > 0) {
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_;
@ -275,11 +413,181 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
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_ = GetLE32s(mem);
dmux->canvas_height_ = GetLE32s(mem);
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_ = GetLE32s(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_) {
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_) {
const ChunkData* const img_components_ = f->img_components_;
if (!img_components_[0].size_ && !img_components_[1].size_) return 0;
// Ensure alpha precedes image bitstream.
if (img_components_[1].size_ &&
img_components_[1].offset_ > img_components_[0].offset_) {
return 0;
}
if (f->width_ <= 0 || f->height_ <= 0) return 0;
} else {
// 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;
@ -325,6 +633,7 @@ WebPDemuxer* WebPDemuxInternal(
}
void WebPDemuxDelete(WebPDemuxer* const dmux) {
Chunk* c;
Frame* f;
if (dmux == NULL) return;
@ -333,9 +642,29 @@ void WebPDemuxDelete(WebPDemuxer* const dmux) {
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* const 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;
}
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif

View File

@ -502,6 +502,22 @@ static WEBP_INLINE WebPDemuxer* WebPDemuxPartial(
// Frees memory associated with 'dmux'.
WEBP_EXTERN(void) WebPDemuxDelete(WebPDemuxer* const dmux);
//------------------------------------------------------------------------------
// Data/information extraction.
typedef enum {
WEBP_FF_FORMAT_FLAGS, // Extended format flags present in the 'VP8X' chunk.
WEBP_FF_CANVAS_WIDTH,
WEBP_FF_CANVAS_HEIGHT,
WEBP_FF_LOOP_COUNT
} WebPFormatFeature;
// Get the 'feature' value from the 'dmux'.
// NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial()
// returned a state > WEBP_DEMUX_PARSING_HEADER.
WEBP_EXTERN(uint32_t) WebPDemuxGetI(
const WebPDemuxer* const dmux, WebPFormatFeature feature);
//------------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)