// 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).
// Note: The following chunk sequences (before the raw VP8/VP8L data) are
// considered valid by this function:
// RIFF + VP8(L)
// RIFF + VP8X + (optional chunks) + VP8(L)
// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose.
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_riff = 0;
int found_vp8x = 0;
VP8StatusCode status;
WebPHeaderStructure hdrs;
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.
status = ParseRIFF(&data, &data_size, &hdrs.riff_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong RIFF header / insufficient data.
}
found_riff = (hdrs.riff_size > 0);
// 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.
}
if (!found_riff && found_vp8x) {
// Note: This restriction may be removed in the future, if it becomes
// necessary to send VP8X chunk to the decoder.
return VP8_STATUS_BITSTREAM_ERROR;
}
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 if data started with "RIFF + VP8X" or "ALPH".
if ((found_riff && found_vp8x) ||
(!found_riff && !found_vp8x && !memcmp(data, "ALPH", TAG_SIZE))) {
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 header.
status = ParseVP8Header(&data, &data_size, hdrs.riff_size,
&hdrs.compressed_size, &hdrs.is_lossless);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8/VP8L chunk-header / insufficient data.
}
if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR;
}
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.
}
// 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).
// Note: The following chunk sequences (before the raw VP8/VP8L data) are
// considered valid by this function:
// RIFF + VP8(L)
// RIFF + VP8X + (optional chunks) + VP8(L)
// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose.
static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
size_t data_size,
int* const width,
int* const height,
int* const has_alpha,
int* const has_animation,
int* const format,
WebPHeaderStructure* const headers) {
int canvas_width = 0;
int canvas_height = 0;
int image_width = 0;
int image_height = 0;
int found_riff = 0;
int found_vp8x = 0;
int animation_present = 0;
int fragments_present = 0;
const int have_all_data = (headers != NULL) ? headers->have_all_data : 0;
VP8StatusCode status;
WebPHeaderStructure hdrs;
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.
status = ParseRIFF(&data, &data_size, have_all_data, &hdrs.riff_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong RIFF header / insufficient data.
}
found_riff = (hdrs.riff_size > 0);
// Skip over VP8X.
{
uint32_t flags = 0;
status = ParseVP8X(&data, &data_size, &found_vp8x,
&canvas_width, &canvas_height, &flags);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8X / insufficient data.
}
animation_present = !!(flags & ANIMATION_FLAG);
fragments_present = !!(flags & FRAGMENTS_FLAG);
if (!found_riff && found_vp8x) {
// Note: This restriction may be removed in the future, if it becomes
// necessary to send VP8X chunk to the decoder.
return VP8_STATUS_BITSTREAM_ERROR;
}
if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG);
if (has_animation != NULL) *has_animation = animation_present;
if (format != NULL) *format = 0; // default = undefined
image_width = canvas_width;
image_height = canvas_height;
if (found_vp8x && (animation_present || fragments_present) &&
headers == NULL) {
status = VP8_STATUS_OK;
goto ReturnWidthHeight; // Just return features from VP8X header.
}
}
if (data_size < TAG_SIZE) {
status = VP8_STATUS_NOT_ENOUGH_DATA;
goto ReturnWidthHeight;
}
// Skip over optional chunks if data started with "RIFF + VP8X" or "ALPH".
if ((found_riff && found_vp8x) ||
(!found_riff && !found_vp8x && !memcmp(data, "ALPH", TAG_SIZE))) {
status = ParseOptionalChunks(&data, &data_size, hdrs.riff_size,
&hdrs.alpha_data, &hdrs.alpha_data_size);
if (status != VP8_STATUS_OK) {
goto ReturnWidthHeight; // Invalid chunk size / insufficient data.
}
}
// Skip over VP8/VP8L header.
status = ParseVP8Header(&data, &data_size, have_all_data, hdrs.riff_size,
&hdrs.compressed_size, &hdrs.is_lossless);
if (status != VP8_STATUS_OK) {
goto ReturnWidthHeight; // Wrong VP8/VP8L chunk-header / insufficient data.
}
if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (format != NULL && !(animation_present || fragments_present)) {
*format = hdrs.is_lossless ? 2 : 1;
}
if (!hdrs.is_lossless) {
if (data_size < VP8_FRAME_HEADER_SIZE) {
status = VP8_STATUS_NOT_ENOUGH_DATA;
goto ReturnWidthHeight;
}
// Validates raw VP8 data.
if (!VP8GetInfo(data, data_size, (uint32_t)hdrs.compressed_size,
&image_width, &image_height)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
} else {
if (data_size < VP8L_FRAME_HEADER_SIZE) {
status = VP8_STATUS_NOT_ENOUGH_DATA;
goto ReturnWidthHeight;
}
// Validates raw VP8L data.
if (!VP8LGetInfo(data, data_size, &image_width, &image_height, has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
// Validates image size coherency.
if (found_vp8x) {
if (canvas_width != image_width || canvas_height != image_height) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
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);
}
ReturnWidthHeight:
if (status == VP8_STATUS_OK ||
(status == VP8_STATUS_NOT_ENOUGH_DATA && found_vp8x && headers == NULL)) {
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 (width != NULL) *width = image_width;
if (height != NULL) *height = image_height;
return VP8_STATUS_OK;
} else {
return status;
}
}
static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
size_t data_size,
int* const width,
int* const height,
int* const has_alpha,
int* const has_animation,
WebPHeaderStructure* const headers) {
int canvas_width = 0;
int canvas_height = 0;
int image_width = 0;
int image_height = 0;
int found_riff = 0;
int found_vp8x = 0;
VP8StatusCode status;
WebPHeaderStructure hdrs;
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;
status = ParseRIFF(&data, &data_size, &hdrs.riff_size);
if (status != VP8_STATUS_OK) {
return status;
}
found_riff = (hdrs.riff_size > 0);
{
uint32_t flags = 0;
int animation_present;
status = ParseVP8X(&data, &data_size, &found_vp8x,
&canvas_width, &canvas_height, &flags);
if (status != VP8_STATUS_OK) {
return status;
}
animation_present = !!(flags & ANIMATION_FLAG);
if (!found_riff && found_vp8x) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG);
if (has_animation != NULL) *has_animation = animation_present;
if (found_vp8x && animation_present && headers == NULL) {
if (width != NULL) *width = canvas_width;
if (height != NULL) *height = canvas_height;
return VP8_STATUS_OK;
}
}
if (data_size < TAG_SIZE) return VP8_STATUS_NOT_ENOUGH_DATA;
if ((found_riff && found_vp8x) ||
(!found_riff && !found_vp8x && !memcmp(data, "ALPH", TAG_SIZE))) {
status = ParseOptionalChunks(&data, &data_size, hdrs.riff_size,
&hdrs.alpha_data, &hdrs.alpha_data_size);
if (status != VP8_STATUS_OK) {
return status;
}
}
status = ParseVP8Header(&data, &data_size, hdrs.riff_size,
&hdrs.compressed_size, &hdrs.is_lossless);
if (status != VP8_STATUS_OK) {
return status;
}
if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (!hdrs.is_lossless) {
if (data_size < VP8_FRAME_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
if (!VP8GetInfo(data, data_size, (uint32_t)hdrs.compressed_size,
&image_width, &image_height)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
} else {
if (data_size < VP8L_FRAME_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
if (!VP8LGetInfo(data, data_size, &image_width, &image_height, has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
if (found_vp8x) {
if (canvas_width != image_width || canvas_height != image_height) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
if (width != NULL) *width = image_width;
if (height != NULL) *height = image_height;
if (has_alpha != NULL) {
*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;
}
