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Refactor decoder library

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- Move common defines to dec/webpi.h
 - Regularize naming and parameters of various "CheckAndSkip" functions.
   Also they return VP8StatusCode for clarity.
 - Move WebP header/chunk parsing functions to webpi.h
 - Fix a bug in static function GetFeatures()

Change-Id: Ibc3da4ba210d860551724dc40741959750d66b89
This commit is contained in:
Urvang Joshi 2011-09-13 09:35:10 +00:00 committed by James Zern
parent 377ef43c3e
commit 76036f547e
5 changed files with 371 additions and 233 deletions
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118
src/dec/idec.c
View File

@ -20,8 +20,6 @@
extern "C" {
#endif
#define RIFF_HEADER_SIZE 12
#define VP8_HEADER_SIZE 10
#define CHUNK_SIZE 4096
#define MAX_MB_SIZE 4096
@ -30,14 +28,20 @@ extern "C" {
// Decoding states. State normally flows like HEADER->PARTS0->DATA->DONE.
// If there is any error the decoder goes into state ERROR.
typedef enum { STATE_HEADER = 0, STATE_PARTS0 = 1,
STATE_DATA = 2, STATE_DONE = 3,
STATE_ERROR = 4
typedef enum {
STATE_PRE_VP8, // All data before that of the first VP8 chunk.
STATE_VP8_FRAME_HEADER, // For VP8 Frame header (within VP8 chunk).
STATE_VP8_PARTS0,
STATE_VP8_DATA,
STATE_DONE,
STATE_ERROR
} DecState;
// Operating state for the MemBuffer
typedef enum { MEM_MODE_NONE = 0,
MEM_MODE_APPEND, MEM_MODE_MAP
typedef enum {
MEM_MODE_NONE = 0,
MEM_MODE_APPEND,
MEM_MODE_MAP
} MemBufferMode;
// storage for partition #0 and partial data (in a rolling fashion)
@ -60,6 +64,7 @@ struct WebPIDecoder {
MemBuffer mem_; // input memory buffer.
WebPDecBuffer output_; // output buffer (when no external one is supplied)
uint32_t vp8_size_; // VP8 size extracted from VP8 Header.
};
// MB context to restore in case VP8DecodeMB() fails
@ -228,7 +233,7 @@ static void RestoreContext(const MBContext* context, VP8Decoder* const dec,
//------------------------------------------------------------------------------
static VP8StatusCode IDecError(WebPIDecoder* idec, VP8StatusCode error) {
if (idec->state_ == STATE_DATA) {
if (idec->state_ == STATE_VP8_DATA) {
VP8Io* const io = &idec->io_;
if (io->teardown) {
io->teardown(io);
@ -238,59 +243,52 @@ static VP8StatusCode IDecError(WebPIDecoder* idec, VP8StatusCode error) {
return error;
}
// Header
static VP8StatusCode DecodeHeader(WebPIDecoder* const idec) {
uint32_t riff_header_size, bits;
static void ChangeState(WebPIDecoder* idec, DecState new_state,
uint32_t consumed_bytes) {
idec->state_ = new_state;
idec->mem_.start_ += consumed_bytes;
assert(idec->mem_.start_ <= idec->mem_.end_);
}
// Headers
static VP8StatusCode DecodeWebPHeaders(WebPIDecoder* const idec) {
const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_;
uint32_t curr_size = MemDataSize(&idec->mem_);
uint32_t chunk_size;
uint32_t riff_size;
int is_vp8x_chunk = 0;
int is_vp8_chunk = 0;
uint32_t vp8_size;
uint32_t bytes_skipped;
VP8StatusCode status;
if (curr_size < RIFF_HEADER_SIZE) {
status = WebPParseHeaders(&data, &curr_size, &vp8_size, &bytes_skipped);
if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_SUSPENDED; // We haven't found a VP8 chunk yet.
} else if (status == VP8_STATUS_OK) {
idec->vp8_size_ = vp8_size;
ChangeState(idec, STATE_VP8_FRAME_HEADER, bytes_skipped);
return VP8_STATUS_OK; // We have skipped all pre-VP8 chunks.
} else {
return IDecError(idec, status);
}
}
static VP8StatusCode DecodeVP8FrameHeader(WebPIDecoder* const idec) {
const uint8_t* data = idec->mem_.buf_ + idec->mem_.start_;
uint32_t curr_size = MemDataSize(&idec->mem_);
uint32_t bits;
if (curr_size < VP8_FRAME_HEADER_SIZE) {
// Not enough data bytes to extract VP8 Frame Header.
return VP8_STATUS_SUSPENDED;
}
if (!WebPCheckAndSkipRIFFHeader(&data, &curr_size, &riff_size)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); // Wrong RIFF Header.
}
if (!VP8XGetInfo(&data, &curr_size, &is_vp8x_chunk, NULL, NULL, NULL)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); // Wrong VP8X Chunk.
}
if (is_vp8x_chunk == -1) {
return VP8_STATUS_SUSPENDED; // Not enough data bytes to process chunk.
}
if (!VP8CheckAndSkipHeader(&data, &curr_size, &is_vp8_chunk, &chunk_size,
riff_size)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR); // Invalid VP8 header.
}
if ((is_vp8_chunk == -1) && (chunk_size == 0)){
return VP8_STATUS_SUSPENDED; // Not enough data bytes to extract chunk_size
}
if (curr_size < VP8_HEADER_SIZE) {
return VP8_STATUS_SUSPENDED; // Not enough data bytes to extract VP8 Header
}
if (!VP8GetInfo(data, curr_size, chunk_size, NULL, NULL, NULL)) {
if (!VP8GetInfo(data, curr_size, idec->vp8_size_, NULL, NULL, NULL)) {
return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
}
riff_header_size = idec->mem_.end_ - curr_size;
bits = data[0] | (data[1] << 8) | (data[2] << 16);
idec->mem_.part0_size_ = (bits >> 5) + VP8_FRAME_HEADER_SIZE;
idec->mem_.part0_size_ = (bits >> 5) + VP8_HEADER_SIZE;
idec->mem_.start_ += riff_header_size;
assert(idec->mem_.start_ <= idec->mem_.end_);
idec->io_.data_size -= riff_header_size;
idec->io_.data_size = curr_size;
idec->io_.data = data;
idec->state_ = STATE_PARTS0;
idec->state_ = STATE_VP8_PARTS0;
return VP8_STATUS_OK;
}
@ -358,7 +356,7 @@ static VP8StatusCode DecodePartition0(WebPIDecoder* const idec) {
// Note: past this point, teardown() must always be called
// in case of error.
idec->state_ = STATE_DATA;
idec->state_ = STATE_VP8_DATA;
// Allocate memory and prepare everything.
if (!VP8InitFrame(dec, io)) {
return IDecError(idec, dec->status_);
@ -422,13 +420,16 @@ static VP8StatusCode IDecode(WebPIDecoder* idec) {
VP8StatusCode status = VP8_STATUS_SUSPENDED;
assert(idec->dec_);
if (idec->state_ == STATE_HEADER) {
status = DecodeHeader(idec);
if (idec->state_ == STATE_PRE_VP8) {
status = DecodeWebPHeaders(idec);
}
if (idec->state_ == STATE_PARTS0) {
if (idec->state_ == STATE_VP8_FRAME_HEADER) {
status = DecodeVP8FrameHeader(idec);
}
if (idec->state_ == STATE_VP8_PARTS0) {
status = DecodePartition0(idec);
}
if (idec->state_ == STATE_DATA) {
if (idec->state_ == STATE_VP8_DATA) {
status = DecodeRemaining(idec);
}
return status;
@ -449,7 +450,7 @@ WebPIDecoder* WebPINewDecoder(WebPDecBuffer* const output_buffer) {
return NULL;
}
idec->state_ = STATE_HEADER;
idec->state_ = STATE_PRE_VP8;
InitMemBuffer(&idec->mem_);
WebPInitDecBuffer(&idec->output_);
@ -465,6 +466,7 @@ WebPIDecoder* WebPINewDecoder(WebPDecBuffer* const output_buffer) {
#else
idec->dec_->use_threads_ = 0;
#endif
idec->vp8_size_ = 0;
return idec;
}
@ -603,7 +605,7 @@ VP8StatusCode WebPIUpdate(WebPIDecoder* const idec, const uint8_t* data,
//------------------------------------------------------------------------------
static const WebPDecBuffer* GetOutputBuffer(const WebPIDecoder* const idec) {
if (!idec || !idec->dec_ || idec->state_ <= STATE_PARTS0) {
if (!idec || !idec->dec_ || idec->state_ <= STATE_VP8_PARTS0) {
return NULL;
}
return idec->params_.output;
@ -667,7 +669,7 @@ int WebPISetIOHooks(WebPIDecoder* const idec,
VP8IoSetupHook setup,
VP8IoTeardownHook teardown,
void* user_data) {
if (!idec || !idec->dec_ || idec->state_ > STATE_HEADER) {
if (!idec || !idec->dec_ || idec->state_ > STATE_PRE_VP8) {
return 0;
}

109
src/dec/vp8.c
View File

@ -17,9 +17,6 @@
extern "C" {
#endif
#define RIFF_HEADER_SIZE 12
#define VP8X_HEADER_SIZE 20
//------------------------------------------------------------------------------
int WebPGetDecoderVersion(void) {
@ -81,39 +78,6 @@ int VP8SetError(VP8Decoder* const dec,
//------------------------------------------------------------------------------
static inline uint32_t get_le32(const uint8_t* const data) {
return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
}
int VP8CheckAndSkipHeader(const uint8_t** data_ptr, uint32_t* data_size_ptr,
int* is_vp8_chunk, uint32_t* chunk_size,
uint32_t riff_size) {
if (!data_ptr || !data_size_ptr || !is_vp8_chunk || !chunk_size) {
return 0; // Invalid Args.
}
if (*data_size_ptr >= 8) {
if (!memcmp(*data_ptr, "VP8 ", 4)) {
*is_vp8_chunk = 1;
*chunk_size = get_le32(*data_ptr + 4);
if ((riff_size >= RIFF_HEADER_SIZE) &&
(*chunk_size > riff_size - RIFF_HEADER_SIZE)) {
return 0; // Inconsistent size information.
}
// We have consumed 8 bytes from VP8 Header. Skip it.
*data_ptr += 8;
*data_size_ptr -= 8;
} else {
*is_vp8_chunk = 0;
*chunk_size = 0;
}
} else {
*is_vp8_chunk = -1; // Insufficient data.
*chunk_size = 0;
}
return 1;
}
int VP8GetInfo(const uint8_t* data, uint32_t data_size, uint32_t chunk_size,
int* width, int* height, int* has_alpha) {
if (data_size < 10) {
@ -161,40 +125,6 @@ int VP8GetInfo(const uint8_t* data, uint32_t data_size, uint32_t chunk_size,
}
}
int VP8XGetInfo(const uint8_t** data_ptr, uint32_t* data_size_ptr,
int* is_vp8x_chunk, int* width, int* height, uint32_t* flags) {
if (!data_ptr || !data_size_ptr || !is_vp8x_chunk) {
return 0; // Invalid Args.
}
if (*data_size_ptr >= VP8X_HEADER_SIZE) {
if (!memcmp(*data_ptr, "VP8X", 4)) {
const uint32_t chunk_size = get_le32(*data_ptr + 4);
*is_vp8x_chunk = 1;
if (chunk_size != (VP8X_HEADER_SIZE - 8)) {
return 0; // Wrong chunk size.
}
if (flags) {
*flags = get_le32(*data_ptr + 8);
}
if (width) {
*width = get_le32(*data_ptr + 12);
}
if (height) {
*height = get_le32(*data_ptr + 16);
}
// We have consumed 20 bytes from VP8X Header. Skip it.
*data_ptr += VP8X_HEADER_SIZE;
*data_size_ptr -= VP8X_HEADER_SIZE;
} else {
*is_vp8x_chunk = 0;
}
} else {
*is_vp8x_chunk = -1; // Insufficient data.
}
return 1;
}
//------------------------------------------------------------------------------
// Header parsing
@ -319,10 +249,8 @@ static int ParseFilterHeader(VP8BitReader* br, VP8Decoder* const dec) {
int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
const uint8_t* buf;
uint32_t buf_size;
uint32_t riff_size;
uint32_t chunk_size;
int is_vp8x_chunk = 0;
int is_vp8_chunk = 0;
uint32_t vp8_chunk_size;
uint32_t bytes_skipped;
VP8FrameHeader* frm_hdr;
VP8PictureHeader* pic_hdr;
VP8BitReader* br;
@ -339,36 +267,17 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
buf = (uint8_t*)io->data;
buf_size = io->data_size;
if (buf == NULL || buf_size <= 4) {
return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
"Not enough data to parse frame header");
}
// Skip over valid RIFF headers.
if (!WebPCheckAndSkipRIFFHeader(&buf, &buf_size, &riff_size)) {
return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
"RIFF: Invalid RIFF container");
}
if (!VP8XGetInfo(&buf, &buf_size, &is_vp8x_chunk, NULL, NULL, NULL)) {
return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
"RIFF: Invalid VP8X container");
}
if (!VP8CheckAndSkipHeader(&buf, &buf_size, &is_vp8_chunk, &chunk_size,
riff_size)) {
return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
"RIFF: Inconsistent size information.");
}
if (is_vp8_chunk == -1) {
return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
"Not enough data to parse frame header.");
// Process Pre-VP8 chunks.
status = WebPParseHeaders(&buf, &buf_size, &vp8_chunk_size, &bytes_skipped);
if (status != VP8_STATUS_OK) {
return VP8SetError(dec, status, "Incorrect/incomplete header.");
}
// Process the VP8 frame header.
if (buf_size < 4) {
return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
"RIFF: Truncated header.");
"Truncated header.");
}
// Paragraph 9.1

24
src/dec/vp8i.h
View File

@ -288,19 +288,6 @@ struct VP8Decoder {
int VP8SetError(VP8Decoder* const dec,
VP8StatusCode error, const char * const msg);
// Validates the VP8 Header and skip over it.
// Returns 0 for invalid (chunk_size greater than riff_size) VP8 header.
// Else return 1.
// is_vp8_chunk is set to:
// 0, in case data bytes don't correspond to VP8 chunk.
// 1, in case data bytes correspond to VP8 chunk.
// -1, in case not enough bytes (partial VP8 chunk) are passed.
// chunk_size is set to the chunk size extracted from the VP8 chunk header. For
// partial VP8 chunk, chunk_size is set to 0.
int VP8CheckAndSkipHeader(const uint8_t** data_ptr, uint32_t* data_size_ptr,
int* is_vp8_chunk, uint32_t* chunk_size,
uint32_t riff_size);
// Validates the VP8 data-header and retrieve basic header information viz width
// and height. Returns 0 in case of formatting error. *width/*height/*has_alpha
// can be passed NULL.
@ -309,17 +296,6 @@ int VP8GetInfo(const uint8_t* data,
uint32_t chunk_size, // total data size expect in the chunk
int *width, int *height, int *has_alpha);
// Validates the VP8X Header and skip over it.
// Returns 0 for invalid VP8X header. Else return 1.
// is_vp8x_chunk is set to:
// 0, in case data bytes doesn't correspond to VP8X chunk.
// 1, in case data bytes correspond to VP8X chunk.
// -1, in case not enough bytes (partial VP8X chunk) are passed.
// Width, Height & Flags are set to the corresponding fields extracted from the
// VP8X chunk.
int VP8XGetInfo(const uint8_t** data_ptr, uint32_t* data_size_ptr,
int* is_vp8x_chunk, int* width, int* height, uint32_t* flags);
// in tree.c
void VP8ResetProba(VP8Proba* const proba);
void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec);

282
src/dec/webp.c
View File

@ -17,8 +17,6 @@
extern "C" {
#endif
#define RIFF_HEADER_SIZE 12
//------------------------------------------------------------------------------
// RIFF layout is:
// 0ffset tag
@ -31,7 +29,7 @@ extern "C" {
// 20.... the VP8 bytes
// Or,
// 12..15 "VP8X": 4-bytes tags, describing the extended-VP8 chunk.
// 16..19 size of the VP8X chunk starting at offset 8.
// 16..19 size of the VP8X chunk starting at offset 20.
// 20..23 VP8X flags bit-map corresponding to the chunk-types present.
// 24..27 Width of the Canvas Image.
// 28..31 Height of the Canvas Image.
@ -44,25 +42,208 @@ static inline uint32_t get_le32(const uint8_t* const data) {
return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
}
uint32_t WebPCheckAndSkipRIFFHeader(const uint8_t** data_ptr,
uint32_t* data_size_ptr,
uint32_t* riff_size) {
if (*data_size_ptr >= RIFF_HEADER_SIZE && !memcmp(*data_ptr, "RIFF", 4)) {
if (memcmp(*data_ptr + 8, "WEBP", 4)) {
return 0; // Wrong image file signature.
VP8StatusCode WebPParseRIFF(const uint8_t** data, uint32_t* data_size,
uint32_t* riff_size) {
assert(data);
assert(data_size);
assert(riff_size);
if (*data_size >= RIFF_HEADER_SIZE &&
!memcmp(*data, "RIFF", TAG_SIZE)) {
if (memcmp(*data + 8, "WEBP", TAG_SIZE)) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong image file signature.
} else {
*riff_size = get_le32(*data_ptr + 4);
if (*riff_size < RIFF_HEADER_SIZE) {
return 0; // We should have at least one chunk.
*riff_size = get_le32(*data + TAG_SIZE);
// Check that we have at least one chunk (i.e "WEBP" + "VP8?nnnn").
if (*riff_size < TAG_SIZE + CHUNK_HEADER_SIZE) {
return VP8_STATUS_BITSTREAM_ERROR;
}
// We have a RIFF container. Skip it.
*data_ptr += RIFF_HEADER_SIZE;
*data_size_ptr -= RIFF_HEADER_SIZE;
*data += RIFF_HEADER_SIZE;
*data_size -= RIFF_HEADER_SIZE;
}
} else {
*riff_size = 0; // Did not get full RIFF Header.
}
return 1;
return VP8_STATUS_OK;
}
VP8StatusCode WebPParseVP8X(const uint8_t** data, uint32_t* data_size,
uint32_t* bytes_skipped,
int* width, int* height, uint32_t* flags) {
assert(data);
assert(data_size);
assert(bytes_skipped);
*bytes_skipped = 0;
if (*data_size < CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
}
if (!memcmp(*data, "VP8X", TAG_SIZE)) {
const uint32_t chunk_size = get_le32(*data + TAG_SIZE);
if (chunk_size != VP8X_CHUNK_SIZE) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong chunk size.
}
if (flags) {
*flags = get_le32(*data + 8);
}
if (width) {
*width = get_le32(*data + 12);
}
if (height) {
*height = get_le32(*data + 16);
}
// We have consumed 20 bytes from VP8X. Skip them.
*bytes_skipped = CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE;
*data += *bytes_skipped;
*data_size -= *bytes_skipped;
}
return VP8_STATUS_OK;
}
VP8StatusCode WebPParseOptionalChunks(const uint8_t** data, uint32_t* data_size,
uint32_t riff_size,
uint32_t* bytes_skipped) {
const uint8_t* buf;
uint32_t buf_size;
assert(data);
assert(data_size);
assert(bytes_skipped);
buf = *data;
buf_size = *data_size;
*bytes_skipped = 0;
while (1) {
uint32_t chunk_size;
uint32_t cur_skip_size;
const uint32_t bytes_skipped_header = TAG_SIZE + // "WEBP".
CHUNK_HEADER_SIZE + // "VP8Xnnnn".
VP8X_CHUNK_SIZE; // Data.
*data = buf;
*data_size = buf_size;
if (buf_size < CHUNK_HEADER_SIZE) { // Insufficient data.
return VP8_STATUS_NOT_ENOUGH_DATA;
}
chunk_size = get_le32(buf + TAG_SIZE);
cur_skip_size = CHUNK_HEADER_SIZE + chunk_size;
// Check that total bytes skipped along with current chunk size
// does not exceed riff_size.
if (riff_size > 0 &&
(bytes_skipped_header + *bytes_skipped + cur_skip_size > riff_size)) {
return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size.
}
if (buf_size < cur_skip_size) { // Insufficient data.
return VP8_STATUS_NOT_ENOUGH_DATA;
}
if (!memcmp(buf, "VP8 ", TAG_SIZE)) { // A valid VP8 header.
return VP8_STATUS_OK; // Found.
}
// We have a full & valid chunk; skip it.
buf += cur_skip_size;
buf_size -= cur_skip_size;
*bytes_skipped += cur_skip_size;
}
}
VP8StatusCode WebPParseVP8Header(const uint8_t** data, uint32_t* data_size,
uint32_t riff_size, uint32_t* bytes_skipped,
uint32_t* vp8_chunk_size) {
assert(data);
assert(data_size);
assert(bytes_skipped);
assert(vp8_chunk_size);
*bytes_skipped = 0;
*vp8_chunk_size = 0;
if (*data_size < CHUNK_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
}
if (!memcmp(*data, "VP8 ", TAG_SIZE)) {
*vp8_chunk_size = get_le32(*data + TAG_SIZE);
if (riff_size >= TAG_SIZE + CHUNK_HEADER_SIZE && // "WEBP" + "VP8 nnnn".
(*vp8_chunk_size > riff_size - (TAG_SIZE + CHUNK_HEADER_SIZE))) {
return VP8_STATUS_BITSTREAM_ERROR; // Inconsistent size information.
}
// We have consumed CHUNK_HEADER_SIZE bytes from VP8 Header. Skip them.
*bytes_skipped = CHUNK_HEADER_SIZE;
*data += *bytes_skipped;
*data_size -= *bytes_skipped;
}
return VP8_STATUS_OK;
}
VP8StatusCode WebPParseHeaders(const uint8_t** data, uint32_t* data_size,
uint32_t* vp8_size, uint32_t* bytes_skipped) {
const uint8_t* buf;
uint32_t buf_size;
uint32_t riff_size;
uint32_t vp8_size_tmp;
uint32_t optional_data_size;
uint32_t vp8x_skip_size;
uint32_t vp8_skip_size;
VP8StatusCode status;
assert(data);
assert(data_size);
assert(vp8_size);
assert(bytes_skipped);
buf = *data;
buf_size = *data_size;
*vp8_size = 0;
*bytes_skipped = 0;
if (buf == NULL || buf_size < RIFF_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
// Skip over RIFF header.
if (WebPParseRIFF(&buf, &buf_size, &riff_size) != VP8_STATUS_OK) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong RIFF Header.
}
// Skip over VP8x header.
status = WebPParseVP8X(&buf, &buf_size, &vp8x_skip_size, NULL, NULL, NULL);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8X Chunk / Insufficient data.
}
if (vp8x_skip_size > 0) {
// Skip over optional chunks.
status = WebPParseOptionalChunks(&buf, &buf_size, riff_size,
&optional_data_size);
if (status != VP8_STATUS_OK) {
return status; // Found an invalid chunk size / Insufficient data.
}
}
// Skip over VP8 chunk header.
status = WebPParseVP8Header(&buf, &buf_size, riff_size, &vp8_skip_size,
&vp8_size_tmp);
if (status != VP8_STATUS_OK) {
return status; // Invalid VP8 header / Insufficient data.
}
if (vp8_skip_size > 0) {
*vp8_size = vp8_size_tmp;
}
*bytes_skipped = buf - *data;
assert(*bytes_skipped == *data_size - buf_size);
*data = buf;
*data_size = buf_size;
return VP8_STATUS_OK;
}
//------------------------------------------------------------------------------
@ -276,56 +457,58 @@ static void DefaultFeatures(WebPBitstreamFeatures* const features) {
features->bitstream_version = 0;
}
static VP8StatusCode GetFeatures(const uint8_t** data, uint32_t* data_size,
static VP8StatusCode GetFeatures(const uint8_t* data, uint32_t data_size,
WebPBitstreamFeatures* const features) {
uint32_t chunk_size = 0;
uint32_t vp8_chunk_size = 0;
uint32_t riff_size = 0;
uint32_t flags = 0;
int is_vp8x_chunk = 0;
int is_vp8_chunk = 0;
uint32_t vp8x_skip_size = 0;
uint32_t vp8_skip_size = 0;
VP8StatusCode status;
if (features == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
DefaultFeatures(features);
if (data == NULL || *data == NULL || data_size == 0) {
if (data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
if (!WebPCheckAndSkipRIFFHeader(data, data_size, &riff_size)) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong RIFF Header.
// Skip over RIFF header.
status = WebPParseRIFF(&data, &data_size, &riff_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong RIFF Header / Insufficient data.
}
if (!VP8XGetInfo(data, data_size, &is_vp8x_chunk,
&features->width, &features->height, &flags)) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong VP8X Chunk-header.
// Skip over VP8x.
status = WebPParseVP8X(&data, &data_size, &vp8x_skip_size, &features->width,
&features->height, &flags);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8X / insufficient data.
}
if (vp8x_skip_size > 0) {
return VP8_STATUS_OK; // Return features from VP8x header.
}
if (is_vp8x_chunk > 0) {
return VP8_STATUS_OK;
// Skip over VP8 header.
status = WebPParseVP8Header(&data, &data_size, riff_size, &vp8_skip_size,
&vp8_chunk_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8 Chunk-header / insufficient data.
}
if (!VP8CheckAndSkipHeader(data, data_size, &is_vp8_chunk, &chunk_size,
riff_size)) {
return VP8_STATUS_BITSTREAM_ERROR; // Invalid VP8 header.
}
if (is_vp8_chunk == -1) {
return VP8_STATUS_BITSTREAM_ERROR; // Insufficient data-bytes.
}
if (!is_vp8_chunk) {
chunk_size = *data_size; // No VP8 chunk wrapper over raw VP8 data.
if (vp8_skip_size == 0) {
vp8_chunk_size = data_size; // No VP8 chunk wrapper over raw VP8 data.
}
// Validates raw VP8 data.
if (!VP8GetInfo(*data, *data_size, chunk_size,
if (!VP8GetInfo(data, data_size, vp8_chunk_size,
&features->width, &features->height, &features->has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
return VP8_STATUS_OK;
return VP8_STATUS_OK; // Return features from VP8 header.
}
//------------------------------------------------------------------------------
@ -335,7 +518,7 @@ int WebPGetInfo(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
WebPBitstreamFeatures features;
if (GetFeatures(&data, &data_size, &features) != VP8_STATUS_OK) {
if (GetFeatures(data, data_size, &features) != VP8_STATUS_OK) {
return 0;
}
@ -368,14 +551,20 @@ int WebPInitDecoderConfigInternal(WebPDecoderConfig* const config,
VP8StatusCode WebPGetFeaturesInternal(const uint8_t* data, uint32_t data_size,
WebPBitstreamFeatures* const features,
int version) {
int version) {
VP8StatusCode status;
if (version != WEBP_DECODER_ABI_VERSION) {
return VP8_STATUS_INVALID_PARAM; // version mismatch
}
if (features == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
return GetFeatures(&data, &data_size, features);
status = GetFeatures(data, data_size, features);
if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_BITSTREAM_ERROR; // Not enough data treated as error.
}
return status;
}
VP8StatusCode WebPDecode(const uint8_t* data, uint32_t data_size,
@ -387,8 +576,11 @@ VP8StatusCode WebPDecode(const uint8_t* data, uint32_t data_size,
return VP8_STATUS_INVALID_PARAM;
}
status = GetFeatures(&data, &data_size, &config->input);
status = GetFeatures(data, data_size, &config->input);
if (status != VP8_STATUS_OK) {
if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_BITSTREAM_ERROR; // Not enough data treated as error.
}
return status;
}

71
src/dec/webpi.h
View File

@ -58,15 +58,74 @@ struct WebPDecParams {
void WebPResetDecParams(WebPDecParams* const params);
//------------------------------------------------------------------------------
// Misc utils
// Header parsing helpers
// Validates the RIFF container (if detected) and skip over it.
// If a RIFF container is detected, returns 0 for invalid header. Else return 1.
#define TAG_SIZE 4
#define CHUNK_HEADER_SIZE 8
#define RIFF_HEADER_SIZE 12
#define VP8X_CHUNK_SIZE 12
#define TILE_CHUNK_SIZE 8
#define FRAME_CHUNK_SIZE 20
#define LOOP_CHUNK_SIZE 4
#define VP8_FRAME_HEADER_SIZE 10 // Size of the frame header within VP8 data.
// Validates the RIFF container (if detected) and skips over it.
// If a RIFF container is detected,
// Returns VP8_STATUS_BITSTREAM_ERROR for invalid header, and
// VP8_STATUS_OK otherwise.
// In case there are not enough bytes (partial RIFF container), return 0 for
// riff_size. Else return the riff_size extracted from the header.
uint32_t WebPCheckAndSkipRIFFHeader(const uint8_t** data_ptr,
uint32_t* data_size_ptr,
uint32_t* riff_size_ptr);
VP8StatusCode WebPParseRIFF(const uint8_t** data, uint32_t* data_size,
uint32_t* riff_size);
// Validates the VP8X Header and skips over it.
// Returns VP8_STATUS_BITSTREAM_ERROR for invalid VP8X header,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If a VP8 chunk is found, bytes_skipped is set to the total number of bytes
// that are skipped; also Width, Height & Flags are set to the corresponding
// fields extracted from the VP8X chunk.
VP8StatusCode WebPParseVP8X(const uint8_t** data, uint32_t* data_size,
uint32_t* bytes_skipped,
int* width, int* height, uint32_t* flags);
// Skips to the next VP8 chunk header in the data given the size of the RIFF
// chunk 'riff_size'.
// Returns VP8_STATUS_BITSTREAM_ERROR if any invalid chunk size is encountered,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If a VP8 chunk is found, bytes_skipped is set to the total number of bytes
// that are skipped.
VP8StatusCode WebPParseOptionalChunks(const uint8_t** data, uint32_t* data_size,
uint32_t riff_size,
uint32_t* bytes_skipped);
// Validates the VP8 Header ("VP8 nnnn") and skips over it.
// Returns VP8_STATUS_BITSTREAM_ERROR for invalid (vp8_chunk_size greater than
// riff_size) VP8 header,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If a VP8 chunk is found, bytes_skipped is set to the total number of bytes
// that are skipped and vp8_chunk_size is set to the corresponding size
// extracted from the VP8 chunk header.
// For a partial VP8 chunk, vp8_chunk_size is set to 0.
VP8StatusCode WebPParseVP8Header(const uint8_t** data, uint32_t* data_size,
uint32_t riff_size, uint32_t* bytes_skipped,
uint32_t* vp8_chunk_size);
// Skips over all valid chunks prior to the first VP8 frame header.
// Returns VP8_STATUS_OK on success,
// VP8_STATUS_BITSTREAM_ERROR if an invalid header/chunk is found, and
// VP8_STATUS_NOT_ENOUGH_DATA if case of insufficient data.
// Also, data, data_size, vp8_size & bytes_skipped are updated appropriately
// on success, where
// vp8_size is the size of VP8 chunk data (extracted from VP8 chunk header) and
// bytes_skipped is set to the total number of bytes that are skipped.
VP8StatusCode WebPParseHeaders(const uint8_t** data, uint32_t* data_size,
uint32_t* vp8_size, uint32_t* bytes_skipped);
//------------------------------------------------------------------------------
// Misc utils
// Initializes VP8Io with custom setup, io and teardown functions. The default
// hooks will use the supplied 'params' as io->opaque handle.