diff options
Diffstat (limited to 'media/libwebp/src/dec/webp_dec.c')
| -rw-r--r-- | media/libwebp/src/dec/webp_dec.c | 852 |
1 files changed, 852 insertions, 0 deletions
diff --git a/media/libwebp/src/dec/webp_dec.c b/media/libwebp/src/dec/webp_dec.c new file mode 100644 index 0000000000..3f4f7bb659 --- /dev/null +++ b/media/libwebp/src/dec/webp_dec.c @@ -0,0 +1,852 @@ +// Copyright 2010 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// Main decoding functions for WEBP images. +// +// Author: Skal (pascal.massimino@gmail.com) + +#include <stdlib.h> + +#include "src/dec/vp8i_dec.h" +#include "src/dec/vp8li_dec.h" +#include "src/dec/webpi_dec.h" +#include "src/utils/utils.h" +#include "src/webp/mux_types.h" // ALPHA_FLAG + +//------------------------------------------------------------------------------ +// RIFF layout is: +// Offset tag +// 0...3 "RIFF" 4-byte tag +// 4...7 size of image data (including metadata) starting at offset 8 +// 8...11 "WEBP" our form-type signature +// The RIFF container (12 bytes) is followed by appropriate chunks: +// 12..15 "VP8 ": 4-bytes tags, signaling the use of VP8 video format +// 16..19 size of the raw VP8 image data, starting at offset 20 +// 20.... the VP8 bytes +// Or, +// 12..15 "VP8L": 4-bytes tags, signaling the use of VP8L lossless format +// 16..19 size of the raw VP8L image data, starting at offset 20 +// 20.... the VP8L bytes +// Or, +// 12..15 "VP8X": 4-bytes tags, describing the extended-VP8 chunk. +// 16..19 size of the VP8X chunk starting at offset 20. +// 20..23 VP8X flags bit-map corresponding to the chunk-types present. +// 24..26 Width of the Canvas Image. +// 27..29 Height of the Canvas Image. +// There can be extra chunks after the "VP8X" chunk (ICCP, ANMF, VP8, VP8L, +// XMP, EXIF ...) +// All sizes are in little-endian order. +// Note: chunk data size must be padded to multiple of 2 when written. + +// Validates the RIFF container (if detected) and skips over it. +// If a RIFF container is detected, returns: +// VP8_STATUS_BITSTREAM_ERROR for invalid header, +// VP8_STATUS_NOT_ENOUGH_DATA for truncated data if have_all_data is true, +// 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. +static VP8StatusCode ParseRIFF(const uint8_t** const data, + size_t* const data_size, int have_all_data, + size_t* const riff_size) { + assert(data != NULL); + assert(data_size != NULL); + assert(riff_size != NULL); + + *riff_size = 0; // Default: no RIFF present. + 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 { + const uint32_t size = GetLE32(*data + TAG_SIZE); + // Check that we have at least one chunk (i.e "WEBP" + "VP8?nnnn"). + if (size < TAG_SIZE + CHUNK_HEADER_SIZE) { + return VP8_STATUS_BITSTREAM_ERROR; + } + if (size > MAX_CHUNK_PAYLOAD) { + return VP8_STATUS_BITSTREAM_ERROR; + } + if (have_all_data && (size > *data_size - CHUNK_HEADER_SIZE)) { + return VP8_STATUS_NOT_ENOUGH_DATA; // Truncated bitstream. + } + // We have a RIFF container. Skip it. + *riff_size = size; + *data += RIFF_HEADER_SIZE; + *data_size -= RIFF_HEADER_SIZE; + } + } + return VP8_STATUS_OK; +} + +// 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 VP8X chunk is found, found_vp8x is set to true and *width_ptr, +// *height_ptr and *flags_ptr are set to the corresponding values extracted +// from the VP8X chunk. +static VP8StatusCode ParseVP8X(const uint8_t** const data, + size_t* const data_size, + int* const found_vp8x, + int* const width_ptr, int* const height_ptr, + uint32_t* const flags_ptr) { + const uint32_t vp8x_size = CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE; + assert(data != NULL); + assert(data_size != NULL); + assert(found_vp8x != NULL); + + *found_vp8x = 0; + + if (*data_size < CHUNK_HEADER_SIZE) { + return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data. + } + + if (!memcmp(*data, "VP8X", TAG_SIZE)) { + int width, height; + uint32_t flags; + const uint32_t chunk_size = GetLE32(*data + TAG_SIZE); + if (chunk_size != VP8X_CHUNK_SIZE) { + return VP8_STATUS_BITSTREAM_ERROR; // Wrong chunk size. + } + + // Verify if enough data is available to validate the VP8X chunk. + if (*data_size < vp8x_size) { + return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data. + } + flags = GetLE32(*data + 8); + width = 1 + GetLE24(*data + 12); + height = 1 + GetLE24(*data + 15); + if (width * (uint64_t)height >= MAX_IMAGE_AREA) { + return VP8_STATUS_BITSTREAM_ERROR; // image is too large + } + + if (flags_ptr != NULL) *flags_ptr = flags; + if (width_ptr != NULL) *width_ptr = width; + if (height_ptr != NULL) *height_ptr = height; + // Skip over VP8X header bytes. + *data += vp8x_size; + *data_size -= vp8x_size; + *found_vp8x = 1; + } + return VP8_STATUS_OK; +} + +// Skips to the next VP8/VP8L 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 an alpha chunk is found, *alpha_data and *alpha_size are set +// appropriately. +static VP8StatusCode ParseOptionalChunks(const uint8_t** const data, + size_t* const data_size, + size_t const riff_size, + const uint8_t** const alpha_data, + size_t* const alpha_size) { + const uint8_t* buf; + size_t buf_size; + uint32_t total_size = TAG_SIZE + // "WEBP". + CHUNK_HEADER_SIZE + // "VP8Xnnnn". + VP8X_CHUNK_SIZE; // data. + assert(data != NULL); + assert(data_size != NULL); + buf = *data; + buf_size = *data_size; + + assert(alpha_data != NULL); + assert(alpha_size != NULL); + *alpha_data = NULL; + *alpha_size = 0; + + while (1) { + uint32_t chunk_size; + uint32_t disk_chunk_size; // chunk_size with padding + + *data = buf; + *data_size = buf_size; + + if (buf_size < CHUNK_HEADER_SIZE) { // Insufficient data. + return VP8_STATUS_NOT_ENOUGH_DATA; + } + + chunk_size = GetLE32(buf + TAG_SIZE); + if (chunk_size > MAX_CHUNK_PAYLOAD) { + return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size. + } + // For odd-sized chunk-payload, there's one byte padding at the end. + disk_chunk_size = (CHUNK_HEADER_SIZE + chunk_size + 1) & ~1u; + total_size += disk_chunk_size; + + // Check that total bytes skipped so far does not exceed riff_size. + if (riff_size > 0 && (total_size > riff_size)) { + return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size. + } + + // Start of a (possibly incomplete) VP8/VP8L chunk implies that we have + // parsed all the optional chunks. + // Note: This check must occur before the check 'buf_size < disk_chunk_size' + // below to allow incomplete VP8/VP8L chunks. + if (!memcmp(buf, "VP8 ", TAG_SIZE) || + !memcmp(buf, "VP8L", TAG_SIZE)) { + return VP8_STATUS_OK; + } + + if (buf_size < disk_chunk_size) { // Insufficient data. + return VP8_STATUS_NOT_ENOUGH_DATA; + } + + if (!memcmp(buf, "ALPH", TAG_SIZE)) { // A valid ALPH header. + *alpha_data = buf + CHUNK_HEADER_SIZE; + *alpha_size = chunk_size; + } + + // We have a full and valid chunk; skip it. + buf += disk_chunk_size; + buf_size -= disk_chunk_size; + } +} + +// Validates the VP8/VP8L Header ("VP8 nnnn" or "VP8L nnnn") and skips over it. +// Returns VP8_STATUS_BITSTREAM_ERROR for invalid (chunk larger than +// riff_size) VP8/VP8L header, +// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and +// VP8_STATUS_OK otherwise. +// If a VP8/VP8L chunk is found, *chunk_size is set to the total number of bytes +// extracted from the VP8/VP8L chunk header. +// The flag '*is_lossless' is set to 1 in case of VP8L chunk / raw VP8L data. +static VP8StatusCode ParseVP8Header(const uint8_t** const data_ptr, + size_t* const data_size, int have_all_data, + size_t riff_size, size_t* const chunk_size, + int* const is_lossless) { + const uint8_t* const data = *data_ptr; + const int is_vp8 = !memcmp(data, "VP8 ", TAG_SIZE); + const int is_vp8l = !memcmp(data, "VP8L", TAG_SIZE); + const uint32_t minimal_size = + TAG_SIZE + CHUNK_HEADER_SIZE; // "WEBP" + "VP8 nnnn" OR + // "WEBP" + "VP8Lnnnn" + assert(data != NULL); + assert(data_size != NULL); + assert(chunk_size != NULL); + assert(is_lossless != NULL); + + if (*data_size < CHUNK_HEADER_SIZE) { + return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data. + } + + if (is_vp8 || is_vp8l) { + // Bitstream contains VP8/VP8L header. + const uint32_t size = GetLE32(data + TAG_SIZE); + if ((riff_size >= minimal_size) && (size > riff_size - minimal_size)) { + return VP8_STATUS_BITSTREAM_ERROR; // Inconsistent size information. + } + if (have_all_data && (size > *data_size - CHUNK_HEADER_SIZE)) { + return VP8_STATUS_NOT_ENOUGH_DATA; // Truncated bitstream. + } + // Skip over CHUNK_HEADER_SIZE bytes from VP8/VP8L Header. + *chunk_size = size; + *data_ptr += CHUNK_HEADER_SIZE; + *data_size -= CHUNK_HEADER_SIZE; + *is_lossless = is_vp8l; + } else { + // Raw VP8/VP8L bitstream (no header). + *is_lossless = VP8LCheckSignature(data, *data_size); + *chunk_size = *data_size; + } + + return VP8_STATUS_OK; +} + +//------------------------------------------------------------------------------ + +// 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; + 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); + 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 && 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) { + *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; + } +} + +VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) { + // status is marked volatile as a workaround for a clang-3.8 (aarch64) bug + volatile VP8StatusCode status; + int has_animation = 0; + assert(headers != NULL); + // fill out headers, ignore width/height/has_alpha. + status = ParseHeadersInternal(headers->data, headers->data_size, + NULL, NULL, NULL, &has_animation, + NULL, headers); + if (status == VP8_STATUS_OK || status == VP8_STATUS_NOT_ENOUGH_DATA) { + // The WebPDemux API + libwebp can be used to decode individual + // uncomposited frames or the WebPAnimDecoder can be used to fully + // reconstruct them (see webp/demux.h). + if (has_animation) { + status = VP8_STATUS_UNSUPPORTED_FEATURE; + } + } + return status; +} + +//------------------------------------------------------------------------------ +// WebPDecParams + +void WebPResetDecParams(WebPDecParams* const params) { + if (params != NULL) { + memset(params, 0, sizeof(*params)); + } +} + +//------------------------------------------------------------------------------ +// "Into" decoding variants + +// Main flow +static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size, + WebPDecParams* const params) { + VP8StatusCode status; + VP8Io io; + WebPHeaderStructure headers; + + headers.data = data; + headers.data_size = data_size; + headers.have_all_data = 1; + status = WebPParseHeaders(&headers); // Process Pre-VP8 chunks. + if (status != VP8_STATUS_OK) { + return status; + } + + assert(params != NULL); + VP8InitIo(&io); + io.data = headers.data + headers.offset; + io.data_size = headers.data_size - headers.offset; + WebPInitCustomIo(params, &io); // Plug the I/O functions. + + if (!headers.is_lossless) { + VP8Decoder* const dec = VP8New(); + if (dec == NULL) { + return VP8_STATUS_OUT_OF_MEMORY; + } + dec->alpha_data_ = headers.alpha_data; + dec->alpha_data_size_ = headers.alpha_data_size; + + // Decode bitstream header, update io->width/io->height. + if (!VP8GetHeaders(dec, &io)) { + status = dec->status_; // An error occurred. Grab error status. + } else { + // Allocate/check output buffers. + status = WebPAllocateDecBuffer(io.width, io.height, params->options, + params->output); + if (status == VP8_STATUS_OK) { // Decode + // This change must be done before calling VP8Decode() + dec->mt_method_ = VP8GetThreadMethod(params->options, &headers, + io.width, io.height); + VP8InitDithering(params->options, dec); + if (!VP8Decode(dec, &io)) { + status = dec->status_; + } + } + } + VP8Delete(dec); + } else { + VP8LDecoder* const dec = VP8LNew(); + if (dec == NULL) { + return VP8_STATUS_OUT_OF_MEMORY; + } + if (!VP8LDecodeHeader(dec, &io)) { + status = dec->status_; // An error occurred. Grab error status. + } else { + // Allocate/check output buffers. + status = WebPAllocateDecBuffer(io.width, io.height, params->options, + params->output); + if (status == VP8_STATUS_OK) { // Decode + if (!VP8LDecodeImage(dec)) { + status = dec->status_; + } + } + } + VP8LDelete(dec); + } + + if (status != VP8_STATUS_OK) { + WebPFreeDecBuffer(params->output); + } else { + if (params->options != NULL && params->options->flip) { + // This restores the original stride values if options->flip was used + // during the call to WebPAllocateDecBuffer above. + status = WebPFlipBuffer(params->output); + } + } + return status; +} + +// Helpers +static uint8_t* DecodeIntoRGBABuffer(WEBP_CSP_MODE colorspace, + const uint8_t* const data, + size_t data_size, + uint8_t* const rgba, + int stride, size_t size) { + WebPDecParams params; + WebPDecBuffer buf; + if (rgba == NULL) { + return NULL; + } + WebPInitDecBuffer(&buf); + WebPResetDecParams(¶ms); + params.output = &buf; + buf.colorspace = colorspace; + buf.u.RGBA.rgba = rgba; + buf.u.RGBA.stride = stride; + buf.u.RGBA.size = size; + buf.is_external_memory = 1; + if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) { + return NULL; + } + return rgba; +} + +uint8_t* WebPDecodeRGBInto(const uint8_t* data, size_t data_size, + uint8_t* output, size_t size, int stride) { + return DecodeIntoRGBABuffer(MODE_RGB, data, data_size, output, stride, size); +} + +uint8_t* WebPDecodeRGBAInto(const uint8_t* data, size_t data_size, + uint8_t* output, size_t size, int stride) { + return DecodeIntoRGBABuffer(MODE_RGBA, data, data_size, output, stride, size); +} + +uint8_t* WebPDecodeARGBInto(const uint8_t* data, size_t data_size, + uint8_t* output, size_t size, int stride) { + return DecodeIntoRGBABuffer(MODE_ARGB, data, data_size, output, stride, size); +} + +uint8_t* WebPDecodeBGRInto(const uint8_t* data, size_t data_size, + uint8_t* output, size_t size, int stride) { + return DecodeIntoRGBABuffer(MODE_BGR, data, data_size, output, stride, size); +} + +uint8_t* WebPDecodeBGRAInto(const uint8_t* data, size_t data_size, + uint8_t* output, size_t size, int stride) { + return DecodeIntoRGBABuffer(MODE_BGRA, data, data_size, output, stride, size); +} + +uint8_t* WebPDecodeYUVInto(const uint8_t* data, size_t data_size, + uint8_t* luma, size_t luma_size, int luma_stride, + uint8_t* u, size_t u_size, int u_stride, + uint8_t* v, size_t v_size, int v_stride) { + WebPDecParams params; + WebPDecBuffer output; + if (luma == NULL) return NULL; + WebPInitDecBuffer(&output); + WebPResetDecParams(¶ms); + params.output = &output; + output.colorspace = MODE_YUV; + output.u.YUVA.y = luma; + output.u.YUVA.y_stride = luma_stride; + output.u.YUVA.y_size = luma_size; + output.u.YUVA.u = u; + output.u.YUVA.u_stride = u_stride; + output.u.YUVA.u_size = u_size; + output.u.YUVA.v = v; + output.u.YUVA.v_stride = v_stride; + output.u.YUVA.v_size = v_size; + output.is_external_memory = 1; + if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) { + return NULL; + } + return luma; +} + +//------------------------------------------------------------------------------ + +static uint8_t* Decode(WEBP_CSP_MODE mode, const uint8_t* const data, + size_t data_size, int* const width, int* const height, + WebPDecBuffer* const keep_info) { + WebPDecParams params; + WebPDecBuffer output; + + WebPInitDecBuffer(&output); + WebPResetDecParams(¶ms); + params.output = &output; + output.colorspace = mode; + + // Retrieve (and report back) the required dimensions from bitstream. + if (!WebPGetInfo(data, data_size, &output.width, &output.height)) { + return NULL; + } + if (width != NULL) *width = output.width; + if (height != NULL) *height = output.height; + + // Decode + if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) { + return NULL; + } + if (keep_info != NULL) { // keep track of the side-info + WebPCopyDecBuffer(&output, keep_info); + } + // return decoded samples (don't clear 'output'!) + return WebPIsRGBMode(mode) ? output.u.RGBA.rgba : output.u.YUVA.y; +} + +uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size, + int* width, int* height) { + return Decode(MODE_RGB, data, data_size, width, height, NULL); +} + +uint8_t* WebPDecodeRGBA(const uint8_t* data, size_t data_size, + int* width, int* height) { + return Decode(MODE_RGBA, data, data_size, width, height, NULL); +} + +uint8_t* WebPDecodeARGB(const uint8_t* data, size_t data_size, + int* width, int* height) { + return Decode(MODE_ARGB, data, data_size, width, height, NULL); +} + +uint8_t* WebPDecodeBGR(const uint8_t* data, size_t data_size, + int* width, int* height) { + return Decode(MODE_BGR, data, data_size, width, height, NULL); +} + +uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size, + int* width, int* height) { + return Decode(MODE_BGRA, data, data_size, width, height, NULL); +} + +uint8_t* WebPDecodeYUV(const uint8_t* data, size_t data_size, + int* width, int* height, uint8_t** u, uint8_t** v, + int* stride, int* uv_stride) { + WebPDecBuffer output; // only to preserve the side-infos + uint8_t* const out = Decode(MODE_YUV, data, data_size, + width, height, &output); + + if (out != NULL) { + const WebPYUVABuffer* const buf = &output.u.YUVA; + *u = buf->u; + *v = buf->v; + *stride = buf->y_stride; + *uv_stride = buf->u_stride; + assert(buf->u_stride == buf->v_stride); + } + return out; +} + +static void DefaultFeatures(WebPBitstreamFeatures* const features) { + assert(features != NULL); + memset(features, 0, sizeof(*features)); +} + +static VP8StatusCode GetFeatures(const uint8_t* const data, size_t data_size, + WebPBitstreamFeatures* const features) { + if (features == NULL || data == NULL) { + return VP8_STATUS_INVALID_PARAM; + } + DefaultFeatures(features); + + // Only parse enough of the data to retrieve the features. + return ParseHeadersInternal(data, data_size, + &features->width, &features->height, + &features->has_alpha, &features->has_animation, + &features->format, NULL); +} + +//------------------------------------------------------------------------------ +// WebPGetInfo() + +int WebPGetInfo(const uint8_t* data, size_t data_size, + int* width, int* height) { + WebPBitstreamFeatures features; + + if (GetFeatures(data, data_size, &features) != VP8_STATUS_OK) { + return 0; + } + + if (width != NULL) { + *width = features.width; + } + if (height != NULL) { + *height = features.height; + } + + return 1; +} + +//------------------------------------------------------------------------------ +// Advance decoding API + +int WebPInitDecoderConfigInternal(WebPDecoderConfig* config, + int version) { + if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) { + return 0; // version mismatch + } + if (config == NULL) { + return 0; + } + memset(config, 0, sizeof(*config)); + DefaultFeatures(&config->input); + WebPInitDecBuffer(&config->output); + return 1; +} + +VP8StatusCode WebPGetFeaturesInternal(const uint8_t* data, size_t data_size, + WebPBitstreamFeatures* features, + int version) { + if (WEBP_ABI_IS_INCOMPATIBLE(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); +} + +VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size, + WebPDecoderConfig* config) { + WebPDecParams params; + VP8StatusCode status; + + if (config == NULL) { + return VP8_STATUS_INVALID_PARAM; + } + + 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; + } + + WebPResetDecParams(¶ms); + params.options = &config->options; + params.output = &config->output; + if (WebPAvoidSlowMemory(params.output, &config->input)) { + // decoding to slow memory: use a temporary in-mem buffer to decode into. + WebPDecBuffer in_mem_buffer; + WebPInitDecBuffer(&in_mem_buffer); + in_mem_buffer.colorspace = config->output.colorspace; + in_mem_buffer.width = config->input.width; + in_mem_buffer.height = config->input.height; + params.output = &in_mem_buffer; + status = DecodeInto(data, data_size, ¶ms); + if (status == VP8_STATUS_OK) { // do the slow-copy + status = WebPCopyDecBufferPixels(&in_mem_buffer, &config->output); + } + WebPFreeDecBuffer(&in_mem_buffer); + } else { + status = DecodeInto(data, data_size, ¶ms); + } + + return status; +} + +//------------------------------------------------------------------------------ +// Cropping and rescaling. + +int WebPCheckCropDimensions(int image_width, int image_height, + int x, int y, int w, int h) { + return !(x < 0 || y < 0 || w <= 0 || h <= 0 || + x >= image_width || w > image_width || w > image_width - x || + y >= image_height || h > image_height || h > image_height - y); +} + +int WebPIoInitFromOptions(const WebPDecoderOptions* const options, + VP8Io* const io, WEBP_CSP_MODE src_colorspace) { + const int W = io->width; + const int H = io->height; + int x = 0, y = 0, w = W, h = H; + + // Cropping + io->use_cropping = (options != NULL) && options->use_cropping; + if (io->use_cropping) { + w = options->crop_width; + h = options->crop_height; + x = options->crop_left; + y = options->crop_top; + if (!WebPIsRGBMode(src_colorspace)) { // only snap for YUV420 + x &= ~1; + y &= ~1; + } + if (!WebPCheckCropDimensions(W, H, x, y, w, h)) { + return 0; // out of frame boundary error + } + } + io->crop_left = x; + io->crop_top = y; + io->crop_right = x + w; + io->crop_bottom = y + h; + io->mb_w = w; + io->mb_h = h; + + // Scaling + io->use_scaling = (options != NULL) && options->use_scaling; + if (io->use_scaling) { + int scaled_width = options->scaled_width; + int scaled_height = options->scaled_height; + if (!WebPRescalerGetScaledDimensions(w, h, &scaled_width, &scaled_height)) { + return 0; + } + io->scaled_width = scaled_width; + io->scaled_height = scaled_height; + } + + // Filter + io->bypass_filtering = (options != NULL) && options->bypass_filtering; + + // Fancy upsampler +#ifdef FANCY_UPSAMPLING + io->fancy_upsampling = (options == NULL) || (!options->no_fancy_upsampling); +#endif + + if (io->use_scaling) { + // disable filter (only for large downscaling ratio). + io->bypass_filtering |= (io->scaled_width < W * 3 / 4) && + (io->scaled_height < H * 3 / 4); + io->fancy_upsampling = 0; + } + return 1; +} + +//------------------------------------------------------------------------------ |