771 lines
26 KiB
C
771 lines
26 KiB
C
// Copyright 2010 Google Inc. All Rights Reserved.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Main decoding functions for WEBP images.
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <stdlib.h>
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#include "./vp8i.h"
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#include "./vp8li.h"
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#include "./webpi.h"
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#include "../webp/format_constants.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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//------------------------------------------------------------------------------
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// RIFF layout is:
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// Offset tag
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// 0...3 "RIFF" 4-byte tag
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// 4...7 size of image data (including metadata) starting at offset 8
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// 8...11 "WEBP" our form-type signature
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// The RIFF container (12 bytes) is followed by appropriate chunks:
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// 12..15 "VP8 ": 4-bytes tags, signaling the use of VP8 video format
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// 16..19 size of the raw VP8 image data, starting at offset 20
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// 20.... the VP8 bytes
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// Or,
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// 12..15 "VP8L": 4-bytes tags, signaling the use of VP8L lossless format
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// 16..19 size of the raw VP8L image data, starting at offset 20
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// 20.... the VP8L bytes
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// Or,
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// 12..15 "VP8X": 4-bytes tags, describing the extended-VP8 chunk.
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// 16..19 size of the VP8X chunk starting at offset 20.
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// 20..23 VP8X flags bit-map corresponding to the chunk-types present.
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// 24..26 Width of the Canvas Image.
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// 27..29 Height of the Canvas Image.
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// There can be extra chunks after the "VP8X" chunk (ICCP, TILE, FRM, VP8,
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// META ...)
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// All sizes are in little-endian order.
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// Note: chunk data size must be padded to multiple of 2 when written.
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static WEBP_INLINE uint32_t get_le24(const uint8_t* const data) {
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return data[0] | (data[1] << 8) | (data[2] << 16);
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}
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static WEBP_INLINE uint32_t get_le32(const uint8_t* const data) {
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return (uint32_t)get_le24(data) | (data[3] << 24);
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}
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// Validates the RIFF container (if detected) and skips over it.
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// If a RIFF container is detected,
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// Returns VP8_STATUS_BITSTREAM_ERROR for invalid header, and
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// VP8_STATUS_OK otherwise.
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// In case there are not enough bytes (partial RIFF container), return 0 for
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// *riff_size. Else return the RIFF size extracted from the header.
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static VP8StatusCode ParseRIFF(const uint8_t** const data,
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size_t* const data_size,
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size_t* const riff_size) {
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assert(data != NULL);
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assert(data_size != NULL);
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assert(riff_size != NULL);
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*riff_size = 0; // Default: no RIFF present.
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if (*data_size >= RIFF_HEADER_SIZE && !memcmp(*data, "RIFF", TAG_SIZE)) {
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if (memcmp(*data + 8, "WEBP", TAG_SIZE)) {
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return VP8_STATUS_BITSTREAM_ERROR; // Wrong image file signature.
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} else {
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const uint32_t size = get_le32(*data + TAG_SIZE);
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// Check that we have at least one chunk (i.e "WEBP" + "VP8?nnnn").
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if (size < TAG_SIZE + CHUNK_HEADER_SIZE) {
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return VP8_STATUS_BITSTREAM_ERROR;
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}
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// We have a RIFF container. Skip it.
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*riff_size = size;
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*data += RIFF_HEADER_SIZE;
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*data_size -= RIFF_HEADER_SIZE;
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}
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}
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return VP8_STATUS_OK;
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}
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// Validates the VP8X header and skips over it.
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// Returns VP8_STATUS_BITSTREAM_ERROR for invalid VP8X header,
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// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
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// VP8_STATUS_OK otherwise.
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// If a VP8X chunk is found, found_vp8x is set to true and *width_ptr,
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// *height_ptr and *flags_ptr are set to the corresponding values extracted
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// from the VP8X chunk.
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static VP8StatusCode ParseVP8X(const uint8_t** const data,
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size_t* const data_size,
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int* const found_vp8x,
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int* const width_ptr, int* const height_ptr,
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uint32_t* const flags_ptr) {
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const uint32_t vp8x_size = CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE;
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assert(data != NULL);
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assert(data_size != NULL);
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assert(found_vp8x != NULL);
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*found_vp8x = 0;
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if (*data_size < CHUNK_HEADER_SIZE) {
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return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
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}
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if (!memcmp(*data, "VP8X", TAG_SIZE)) {
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int width, height;
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uint32_t flags;
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const uint32_t chunk_size = get_le32(*data + TAG_SIZE);
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if (chunk_size != VP8X_CHUNK_SIZE) {
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return VP8_STATUS_BITSTREAM_ERROR; // Wrong chunk size.
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}
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// Verify if enough data is available to validate the VP8X chunk.
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if (*data_size < vp8x_size) {
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return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
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}
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flags = get_le32(*data + 8);
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width = 1 + get_le24(*data + 12);
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height = 1 + get_le24(*data + 15);
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if (width * (uint64_t)height >= MAX_IMAGE_AREA) {
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return VP8_STATUS_BITSTREAM_ERROR; // image is too large
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}
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if (flags_ptr != NULL) *flags_ptr = flags;
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if (width_ptr != NULL) *width_ptr = width;
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if (height_ptr != NULL) *height_ptr = height;
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// Skip over VP8X header bytes.
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*data += vp8x_size;
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*data_size -= vp8x_size;
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*found_vp8x = 1;
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}
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return VP8_STATUS_OK;
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}
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// Skips to the next VP8/VP8L chunk header in the data given the size of the
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// RIFF chunk 'riff_size'.
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// Returns VP8_STATUS_BITSTREAM_ERROR if any invalid chunk size is encountered,
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// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
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// VP8_STATUS_OK otherwise.
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// If an alpha chunk is found, *alpha_data and *alpha_size are set
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// appropriately.
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static VP8StatusCode ParseOptionalChunks(const uint8_t** const data,
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size_t* const data_size,
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size_t const riff_size,
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const uint8_t** const alpha_data,
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size_t* const alpha_size) {
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const uint8_t* buf;
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size_t buf_size;
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uint32_t total_size = TAG_SIZE + // "WEBP".
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CHUNK_HEADER_SIZE + // "VP8Xnnnn".
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VP8X_CHUNK_SIZE; // data.
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assert(data != NULL);
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assert(data_size != NULL);
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buf = *data;
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buf_size = *data_size;
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assert(alpha_data != NULL);
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assert(alpha_size != NULL);
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*alpha_data = NULL;
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*alpha_size = 0;
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while (1) {
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uint32_t chunk_size;
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uint32_t disk_chunk_size; // chunk_size with padding
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*data = buf;
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*data_size = buf_size;
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if (buf_size < CHUNK_HEADER_SIZE) { // Insufficient data.
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return VP8_STATUS_NOT_ENOUGH_DATA;
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}
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chunk_size = get_le32(buf + TAG_SIZE);
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// For odd-sized chunk-payload, there's one byte padding at the end.
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disk_chunk_size = (CHUNK_HEADER_SIZE + chunk_size + 1) & ~1;
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total_size += disk_chunk_size;
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// Check that total bytes skipped so far does not exceed riff_size.
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if (riff_size > 0 && (total_size > riff_size)) {
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return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size.
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}
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if (buf_size < disk_chunk_size) { // Insufficient data.
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return VP8_STATUS_NOT_ENOUGH_DATA;
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}
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if (!memcmp(buf, "ALPH", TAG_SIZE)) { // A valid ALPH header.
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*alpha_data = buf + CHUNK_HEADER_SIZE;
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*alpha_size = chunk_size;
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} else if (!memcmp(buf, "VP8 ", TAG_SIZE) ||
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!memcmp(buf, "VP8L", TAG_SIZE)) { // A valid VP8/VP8L header.
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return VP8_STATUS_OK; // Found.
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}
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// We have a full and valid chunk; skip it.
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buf += disk_chunk_size;
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buf_size -= disk_chunk_size;
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}
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}
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// Validates the VP8/VP8L Header ("VP8 nnnn" or "VP8L nnnn") and skips over it.
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// Returns VP8_STATUS_BITSTREAM_ERROR for invalid (chunk larger than
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// riff_size) VP8/VP8L header,
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// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
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// VP8_STATUS_OK otherwise.
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// If a VP8/VP8L chunk is found, *chunk_size is set to the total number of bytes
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// extracted from the VP8/VP8L chunk header.
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// The flag '*is_lossless' is set to 1 in case of VP8L chunk / raw VP8L data.
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static VP8StatusCode ParseVP8Header(const uint8_t** const data_ptr,
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size_t* const data_size,
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size_t riff_size,
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size_t* const chunk_size,
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int* const is_lossless) {
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const uint8_t* const data = *data_ptr;
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const int is_vp8 = !memcmp(data, "VP8 ", TAG_SIZE);
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const int is_vp8l = !memcmp(data, "VP8L", TAG_SIZE);
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const uint32_t minimal_size =
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TAG_SIZE + CHUNK_HEADER_SIZE; // "WEBP" + "VP8 nnnn" OR
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// "WEBP" + "VP8Lnnnn"
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assert(data != NULL);
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assert(data_size != NULL);
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assert(chunk_size != NULL);
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assert(is_lossless != NULL);
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if (*data_size < CHUNK_HEADER_SIZE) {
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return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
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}
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if (is_vp8 || is_vp8l) {
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// Bitstream contains VP8/VP8L header.
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const uint32_t size = get_le32(data + TAG_SIZE);
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if ((riff_size >= minimal_size) && (size > riff_size - minimal_size)) {
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return VP8_STATUS_BITSTREAM_ERROR; // Inconsistent size information.
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}
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// Skip over CHUNK_HEADER_SIZE bytes from VP8/VP8L Header.
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*chunk_size = size;
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*data_ptr += CHUNK_HEADER_SIZE;
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*data_size -= CHUNK_HEADER_SIZE;
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*is_lossless = is_vp8l;
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} else {
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// Raw VP8/VP8L bitstream (no header).
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*is_lossless = VP8LCheckSignature(data, *data_size);
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*chunk_size = *data_size;
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}
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return VP8_STATUS_OK;
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}
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//------------------------------------------------------------------------------
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// Fetch '*width', '*height', '*has_alpha' and fill out 'headers' based on
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// 'data'. All the output parameters may be NULL. If 'headers' is NULL only the
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// minimal amount will be read to fetch the remaining parameters.
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// If 'headers' is non-NULL this function will attempt to locate both alpha
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// data (with or without a VP8X chunk) and the bitstream chunk (VP8/VP8L).
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// Note: The following chunk sequences (before the raw VP8/VP8L data) are
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// considered valid by this function:
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// RIFF + VP8(L)
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// RIFF + VP8X + (optional chunks) + VP8(L)
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// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
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// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose.
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static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
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size_t data_size,
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int* const width,
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int* const height,
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int* const has_alpha,
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WebPHeaderStructure* const headers) {
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int found_riff = 0;
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int found_vp8x = 0;
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VP8StatusCode status;
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WebPHeaderStructure hdrs;
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if (data == NULL || data_size < RIFF_HEADER_SIZE) {
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return VP8_STATUS_NOT_ENOUGH_DATA;
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}
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memset(&hdrs, 0, sizeof(hdrs));
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hdrs.data = data;
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hdrs.data_size = data_size;
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// Skip over RIFF header.
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status = ParseRIFF(&data, &data_size, &hdrs.riff_size);
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if (status != VP8_STATUS_OK) {
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return status; // Wrong RIFF header / insufficient data.
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}
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found_riff = (hdrs.riff_size > 0);
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// Skip over VP8X.
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{
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uint32_t flags = 0;
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status = ParseVP8X(&data, &data_size, &found_vp8x, width, height, &flags);
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if (status != VP8_STATUS_OK) {
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return status; // Wrong VP8X / insufficient data.
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}
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if (!found_riff && found_vp8x) {
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// Note: This restriction may be removed in the future, if it becomes
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// necessary to send VP8X chunk to the decoder.
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return VP8_STATUS_BITSTREAM_ERROR;
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}
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if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG_BIT);
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if (found_vp8x && headers == NULL) {
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return VP8_STATUS_OK; // Return features from VP8X header.
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}
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}
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if (data_size < TAG_SIZE) return VP8_STATUS_NOT_ENOUGH_DATA;
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// Skip over optional chunks if data started with "RIFF + VP8X" or "ALPH".
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if ((found_riff && found_vp8x) ||
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(!found_riff && !found_vp8x && !memcmp(data, "ALPH", TAG_SIZE))) {
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status = ParseOptionalChunks(&data, &data_size, hdrs.riff_size,
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&hdrs.alpha_data, &hdrs.alpha_data_size);
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if (status != VP8_STATUS_OK) {
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return status; // Found an invalid chunk size / insufficient data.
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}
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}
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// Skip over VP8/VP8L header.
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status = ParseVP8Header(&data, &data_size, hdrs.riff_size,
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&hdrs.compressed_size, &hdrs.is_lossless);
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if (status != VP8_STATUS_OK) {
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return status; // Wrong VP8/VP8L chunk-header / insufficient data.
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}
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if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
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return VP8_STATUS_BITSTREAM_ERROR;
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}
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if (!hdrs.is_lossless) {
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if (data_size < VP8_FRAME_HEADER_SIZE) {
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return VP8_STATUS_NOT_ENOUGH_DATA;
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}
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// Validates raw VP8 data.
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if (!VP8GetInfo(data, data_size,
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(uint32_t)hdrs.compressed_size, width, height)) {
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return VP8_STATUS_BITSTREAM_ERROR;
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}
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} else {
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if (data_size < VP8L_FRAME_HEADER_SIZE) {
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return VP8_STATUS_NOT_ENOUGH_DATA;
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}
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// Validates raw VP8L data.
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if (!VP8LGetInfo(data, data_size, width, height, has_alpha)) {
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return VP8_STATUS_BITSTREAM_ERROR;
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}
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}
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if (has_alpha != NULL) {
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// If the data did not contain a VP8X/VP8L chunk the only definitive way
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// to set this is by looking for alpha data (from an ALPH chunk).
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*has_alpha |= (hdrs.alpha_data != NULL);
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}
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if (headers != NULL) {
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*headers = hdrs;
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headers->offset = data - headers->data;
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assert((uint64_t)(data - headers->data) < MAX_CHUNK_PAYLOAD);
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assert(headers->offset == headers->data_size - data_size);
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}
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return VP8_STATUS_OK; // Return features from VP8 header.
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}
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VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
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assert(headers != NULL);
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// fill out headers, ignore width/height/has_alpha.
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return ParseHeadersInternal(headers->data, headers->data_size,
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NULL, NULL, NULL, headers);
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}
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//------------------------------------------------------------------------------
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// WebPDecParams
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void WebPResetDecParams(WebPDecParams* const params) {
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if (params) {
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memset(params, 0, sizeof(*params));
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}
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}
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//------------------------------------------------------------------------------
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// "Into" decoding variants
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// Main flow
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static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
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WebPDecParams* const params) {
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VP8StatusCode status;
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VP8Io io;
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WebPHeaderStructure headers;
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headers.data = data;
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headers.data_size = data_size;
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status = WebPParseHeaders(&headers); // Process Pre-VP8 chunks.
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if (status != VP8_STATUS_OK) {
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return status;
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}
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assert(params != NULL);
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VP8InitIo(&io);
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io.data = headers.data + headers.offset;
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io.data_size = headers.data_size - headers.offset;
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WebPInitCustomIo(params, &io); // Plug the I/O functions.
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if (!headers.is_lossless) {
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VP8Decoder* const dec = VP8New();
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if (dec == NULL) {
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return VP8_STATUS_OUT_OF_MEMORY;
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}
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#ifdef WEBP_USE_THREAD
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dec->use_threads_ = params->options && (params->options->use_threads > 0);
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#else
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dec->use_threads_ = 0;
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#endif
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dec->alpha_data_ = headers.alpha_data;
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dec->alpha_data_size_ = headers.alpha_data_size;
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// Decode bitstream header, update io->width/io->height.
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if (!VP8GetHeaders(dec, &io)) {
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status = dec->status_; // An error occurred. Grab error status.
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} else {
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// Allocate/check output buffers.
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status = WebPAllocateDecBuffer(io.width, io.height, params->options,
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params->output);
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if (status == VP8_STATUS_OK) { // Decode
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if (!VP8Decode(dec, &io)) {
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status = dec->status_;
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}
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}
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}
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VP8Delete(dec);
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} else {
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VP8LDecoder* const dec = VP8LNew();
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if (dec == NULL) {
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return VP8_STATUS_OUT_OF_MEMORY;
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}
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if (!VP8LDecodeHeader(dec, &io)) {
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status = dec->status_; // An error occurred. Grab error status.
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} else {
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// Allocate/check output buffers.
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status = WebPAllocateDecBuffer(io.width, io.height, params->options,
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params->output);
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if (status == VP8_STATUS_OK) { // Decode
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if (!VP8LDecodeImage(dec)) {
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status = dec->status_;
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}
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}
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}
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VP8LDelete(dec);
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}
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if (status != VP8_STATUS_OK) {
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WebPFreeDecBuffer(params->output);
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}
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return status;
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}
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// Helpers
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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));
|
|
features->bitstream_version = 0;
|
|
}
|
|
|
|
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 width/height/has_alpha.
|
|
return ParseHeadersInternal(data, data_size,
|
|
&features->width, &features->height,
|
|
&features->has_alpha, 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) {
|
|
VP8StatusCode status;
|
|
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;
|
|
}
|
|
|
|
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, 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.output = &config->output;
|
|
params.options = &config->options;
|
|
status = DecodeInto(data, data_size, ¶ms);
|
|
|
|
return status;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Cropping and rescaling.
|
|
|
|
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 > 0);
|
|
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 or YUV422
|
|
x &= ~1;
|
|
y &= ~1; // TODO(later): only for YUV420, not YUV422.
|
|
}
|
|
if (x < 0 || y < 0 || w <= 0 || h <= 0 || x + w > W || y + h > 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 > 0);
|
|
if (io->use_scaling) {
|
|
if (options->scaled_width <= 0 || options->scaled_height <= 0) {
|
|
return 0;
|
|
}
|
|
io->scaled_width = options->scaled_width;
|
|
io->scaled_height = options->scaled_height;
|
|
}
|
|
|
|
// Filter
|
|
io->bypass_filtering = options && 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;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
|
} // extern "C"
|
|
#endif
|