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Merge "modify WebPParseHeaders to allow reuse by GetFeatures"

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This commit is contained in:
James Zern 2012-06-12 23:51:55 -07:00 committed by Gerrit Code Review
commit 2f66668882
3 changed files with 100 additions and 87 deletions
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3
src/dec/vp8l.c
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@ -22,7 +22,6 @@ extern "C" {
#define NUM_ARGB_CACHE_ROWS 16
static const size_t kHeaderBytes = 5;
static const int kCodeLengthLiterals = 16;
static const int kCodeLengthRepeatCode = 16;
static const int kCodeLengthExtraBits[3] = { 2, 3, 7 };
@ -98,7 +97,7 @@ static int ReadImageInfo(VP8LBitReader* const br,
int VP8LGetInfo(const uint8_t* data, size_t data_size,
int* const width, int* const height, int* const has_alpha) {
if (data == NULL || data_size < kHeaderBytes) {
if (data == NULL || data_size < VP8L_FRAME_HEADER_SIZE) {
return 0; // not enough data
} else {
int w, h, a;

179
src/dec/webp.c
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@ -241,58 +241,117 @@ static VP8StatusCode ParseVP8Header(const uint8_t** data_ptr, size_t* data_size,
//------------------------------------------------------------------------------
VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
const uint8_t* buf;
size_t buf_size;
int found_vp8x;
// Returns true if 'fourcc' matches a chunk that can appear in a 'VP8X' file.
// Image chunks are dealt with separately so are not included here.
static int IsExtendedFormatChunk(const uint8_t fourcc[4]) {
return (!memcmp(fourcc, "ALPH", TAG_SIZE) ||
!memcmp(fourcc, "FRM ", TAG_SIZE) ||
!memcmp(fourcc, "ICCP", TAG_SIZE) ||
!memcmp(fourcc, "LOOP", TAG_SIZE) ||
!memcmp(fourcc, "META", TAG_SIZE) ||
!memcmp(fourcc, "TILE", TAG_SIZE));
}
// Fetch 'width', 'height', 'has_alpha' and fill out 'headers' based on 'data'.
// All the output parameters may be NULL. If 'headers' is NULL only the minimal
// amount will be read to fetch the remaining parameters.
// If 'headers' is non-NULL this function will attempt to locate both alpha
// data (with or without a VP8X chunk) and the bitstream chunk (VP8/VP8L).
static VP8StatusCode ParseHeadersInternal(
const uint8_t* data, size_t data_size,
int* const width, int* const height, int* const has_alpha,
WebPHeaderStructure* const headers) {
int found_vp8x = 0;
VP8StatusCode status;
WebPHeaderStructure hdrs;
assert(headers);
buf = headers->data;
buf_size = headers->data_size;
headers->alpha_data = NULL;
headers->alpha_data_size = 0;
headers->compressed_size = 0;
headers->is_lossless = 0;
headers->offset = 0;
headers->riff_size = 0;
if (buf == NULL || buf_size < RIFF_HEADER_SIZE) {
if (data == NULL || data_size < RIFF_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
memset(&hdrs, 0, sizeof(hdrs));
hdrs.data = data;
hdrs.data_size = data_size;
// Skip over RIFF header.
if (ParseRIFF(&buf, &buf_size, &headers->riff_size) != VP8_STATUS_OK) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong RIFF header.
status = ParseRIFF(&data, &data_size, &hdrs.riff_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong RIFF header / insufficient data.
}
// Skip over VP8X header.
status = ParseVP8X(&buf, &buf_size, &found_vp8x, NULL, NULL, NULL);
// Skip over VP8X.
{
uint32_t flags = 0;
status = ParseVP8X(&data, &data_size, &found_vp8x, width, height, &flags);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8X chunk / insufficient data.
return status; // Wrong VP8X / insufficient data.
}
if (found_vp8x) {
if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG_BIT);
if (found_vp8x && headers == NULL) {
return VP8_STATUS_OK; // Return features from VP8X header.
}
}
if (data_size < TAG_SIZE) return VP8_STATUS_NOT_ENOUGH_DATA;
// Skip over optional chunks.
status = ParseOptionalChunks(&buf, &buf_size, headers->riff_size,
&headers->alpha_data,
&headers->alpha_data_size);
// If a VP8X chunk was not found look for chunks that may be contained within
// one to initiate the parse.
if (found_vp8x || IsExtendedFormatChunk(data)) {
status = ParseOptionalChunks(&data, &data_size, hdrs.riff_size,
&hdrs.alpha_data, &hdrs.alpha_data_size);
if (status != VP8_STATUS_OK) {
return status; // Found an invalid chunk size / insufficient data.
}
}
// Skip over VP8/VP8L chunk header.
status = ParseVP8Header(&buf, &buf_size, headers->riff_size,
&headers->compressed_size, &headers->is_lossless);
// Skip over VP8/VP8L header.
status = ParseVP8Header(&data, &data_size, hdrs.riff_size,
&hdrs.compressed_size, &hdrs.is_lossless);
if (status != VP8_STATUS_OK) {
return status; // Invalid VP8/VP8L header / insufficient data.
return status; // Wrong VP8/VP8L chunk-header / insufficient data.
}
if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR;
}
headers->offset = (uint32_t)(buf - headers->data);
assert((uint64_t)(buf - headers->data) < MAX_CHUNK_PAYLOAD);
assert(headers->offset == headers->data_size - buf_size);
return VP8_STATUS_OK;
if (!hdrs.is_lossless) {
if (data_size < VP8_FRAME_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
// Validates raw VP8 data.
if (!VP8GetInfo(data, data_size,
(uint32_t)hdrs.compressed_size, width, height)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
} else {
if (data_size < VP8L_FRAME_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
// Validates raw VP8L data.
if (!VP8LGetInfo(data, data_size, width, height, has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
if (has_alpha != NULL) {
// If the data did not contain a VP8X/VP8L chunk the only definitive way
// to set this is by looking for alpha data (from an ALPH chunk).
*has_alpha |= (hdrs.alpha_data != NULL);
}
if (headers != NULL) {
*headers = hdrs;
headers->offset = data - headers->data;
assert((uint64_t)(data - headers->data) < MAX_CHUNK_PAYLOAD);
assert(headers->offset == headers->data_size - data_size);
}
return VP8_STATUS_OK; // Return features from VP8 header.
}
VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
assert(headers != NULL);
// fill out headers, ignore width/height/has_alpha.
return ParseHeadersInternal(headers->data, headers->data_size,
NULL, NULL, NULL, headers);
}
//------------------------------------------------------------------------------
@ -537,61 +596,15 @@ static void DefaultFeatures(WebPBitstreamFeatures* const features) {
static VP8StatusCode GetFeatures(const uint8_t* data, size_t data_size,
WebPBitstreamFeatures* const features) {
size_t chunk_size = 0;
size_t riff_size = 0;
int* const width = &features->width;
int* const height = &features->height;
int found_vp8x;
int is_lossless = 0;
VP8StatusCode status;
if (features == NULL || data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
DefaultFeatures(features);
// Skip over RIFF header.
status = ParseRIFF(&data, &data_size, &riff_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong RIFF header / insufficient data.
}
// Skip over VP8X.
{
uint32_t flags = 0;
status = ParseVP8X(&data, &data_size, &found_vp8x, width, height, &flags);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8X / insufficient data.
}
features->has_alpha = !!(flags & ALPHA_FLAG_BIT);
if (found_vp8x) {
return VP8_STATUS_OK; // Return features from VP8X header.
}
}
// Skip over VP8/VP8L header.
status = ParseVP8Header(&data, &data_size, riff_size,
&chunk_size, &is_lossless);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8/VP8L chunk-header / insufficient data.
}
if (!is_lossless) {
// Validates raw VP8 data.
if (chunk_size != (uint32_t)chunk_size ||
!VP8GetInfo(data, data_size, (uint32_t)chunk_size, width, height)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
} else {
int has_alpha;
// Validates raw VP8L data.
if (!VP8LGetInfo(data, data_size, width, height, &has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
features->has_alpha = has_alpha;
}
return VP8_STATUS_OK; // Return features from VP8 header.
// Only parse enough of the data to retrieve width/height/has_alpha.
return ParseHeadersInternal(data, data_size,
&features->width, &features->height,
&features->has_alpha, NULL);
}
//------------------------------------------------------------------------------

1
src/webp/format_constants.h
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@ -25,6 +25,7 @@
// width and height.
#define VP8L_VERSION_BITS 3 // 3 bits reserved for version.
#define VP8L_VERSION 0 // version 0
#define VP8L_FRAME_HEADER_SIZE 5 // Size of the VP8L frame header.
#define MAX_PALETTE_SIZE 256
#define MAX_CACHE_BITS 11