11e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Copyright 2012 Google Inc. All Rights Reserved. 21e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// 30406ce1417f76f2034833414dcecc9f56253640cVikas Arora// Use of this source code is governed by a BSD-style license 40406ce1417f76f2034833414dcecc9f56253640cVikas Arora// that can be found in the COPYING file in the root of the source 50406ce1417f76f2034833414dcecc9f56253640cVikas Arora// tree. An additional intellectual property rights grant can be found 60406ce1417f76f2034833414dcecc9f56253640cVikas Arora// in the file PATENTS. All contributing project authors may 70406ce1417f76f2034833414dcecc9f56253640cVikas Arora// be found in the AUTHORS file in the root of the source tree. 81e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// ----------------------------------------------------------------------------- 91e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// 101e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Demux API. 111e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Enables extraction of image and extended format data from WebP files. 121e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 131e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Code Example: Demuxing WebP data to extract all the frames, ICC profile 141e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// and EXIF/XMP metadata. 158b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora/* 168b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPDemuxer* demux = WebPDemux(&webp_data); 178b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora 188b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH); 198b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT); 208b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Get information about the features present in the WebP file). 218b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS); 228b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora 238b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Iterate over all frames). 248b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPIterator iter; 258b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora if (WebPDemuxGetFrame(demux, 1, &iter)) { 268b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora do { 278b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(), 288b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... and get other frame properties like width, height, offsets etc. 298b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... see 'struct WebPIterator' below for more info). 308b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora } while (WebPDemuxNextFrame(&iter)); 318b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPDemuxReleaseIterator(&iter); 328b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora } 338b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora 348b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Extract metadata). 358b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPChunkIterator chunk_iter; 368b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter); 378b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Consume the ICC profile in 'chunk_iter.chunk'). 388b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPDemuxReleaseChunkIterator(&chunk_iter); 398b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter); 408b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Consume the EXIF metadata in 'chunk_iter.chunk'). 418b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPDemuxReleaseChunkIterator(&chunk_iter); 428b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter); 438b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // ... (Consume the XMP metadata in 'chunk_iter.chunk'). 448b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPDemuxReleaseChunkIterator(&chunk_iter); 458b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WebPDemuxDelete(demux); 468b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora*/ 471e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 481e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora#ifndef WEBP_WEBP_DEMUX_H_ 491e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora#define WEBP_WEBP_DEMUX_H_ 501e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 511e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora#include "./mux_types.h" 521e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 538b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora#ifdef __cplusplus 541e7bf8805bd030c19924a5306837ecd72c295751Vikas Aroraextern "C" { 551e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora#endif 561e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 575807b79d0acff7f1bc35c01da54dd51541049137Vikas Arora#define WEBP_DEMUX_ABI_VERSION 0x0101 // MAJOR(8b) + MINOR(8b) 581e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 590406ce1417f76f2034833414dcecc9f56253640cVikas Arora// Note: forward declaring enumerations is not allowed in (strict) C and C++, 600406ce1417f76f2034833414dcecc9f56253640cVikas Arora// the types are left here for reference. 610406ce1417f76f2034833414dcecc9f56253640cVikas Arora// typedef enum WebPDemuxState WebPDemuxState; 620406ce1417f76f2034833414dcecc9f56253640cVikas Arora// typedef enum WebPFormatFeature WebPFormatFeature; 631e7bf8805bd030c19924a5306837ecd72c295751Vikas Aroratypedef struct WebPDemuxer WebPDemuxer; 641e7bf8805bd030c19924a5306837ecd72c295751Vikas Aroratypedef struct WebPIterator WebPIterator; 651e7bf8805bd030c19924a5306837ecd72c295751Vikas Aroratypedef struct WebPChunkIterator WebPChunkIterator; 661e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 671e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora//------------------------------------------------------------------------------ 681e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 691e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns the version number of the demux library, packed in hexadecimal using 701e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507. 711e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPGetDemuxVersion(void); 721e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 731e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora//------------------------------------------------------------------------------ 741e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Life of a Demux object 751e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 760406ce1417f76f2034833414dcecc9f56253640cVikas Aroratypedef enum WebPDemuxState { 778b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WEBP_DEMUX_PARSE_ERROR = -1, // An error occurred while parsing. 788b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WEBP_DEMUX_PARSING_HEADER = 0, // Not enough data to parse full header. 798b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WEBP_DEMUX_PARSED_HEADER = 1, // Header parsing complete, 808b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora // data may be available. 818b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora WEBP_DEMUX_DONE = 2 // Entire file has been parsed. 820406ce1417f76f2034833414dcecc9f56253640cVikas Arora} WebPDemuxState; 831e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 841e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Internal, version-checked, entry point 851e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(WebPDemuxer*) WebPDemuxInternal( 861e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora const WebPData*, int, WebPDemuxState*, int); 871e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 880406ce1417f76f2034833414dcecc9f56253640cVikas Arora// Parses the full WebP file given by 'data'. 891e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns a WebPDemuxer object on successful parse, NULL otherwise. 901e7bf8805bd030c19924a5306837ecd72c295751Vikas Arorastatic WEBP_INLINE WebPDemuxer* WebPDemux(const WebPData* data) { 911e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora return WebPDemuxInternal(data, 0, NULL, WEBP_DEMUX_ABI_VERSION); 921e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora} 931e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 940406ce1417f76f2034833414dcecc9f56253640cVikas Arora// Parses the possibly incomplete WebP file given by 'data'. 951e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// If 'state' is non-NULL it will be set to indicate the status of the demuxer. 968b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// Returns NULL in case of error or if there isn't enough data to start parsing; 978b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// and a WebPDemuxer object on successful parse. 988b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// Note that WebPDemuxer keeps internal pointers to 'data' memory segment. 998b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// If this data is volatile, the demuxer object should be deleted (by calling 1008b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// WebPDemuxDelete()) and WebPDemuxPartial() called again on the new data. 1018b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// This is usually an inexpensive operation. 1021e7bf8805bd030c19924a5306837ecd72c295751Vikas Arorastatic WEBP_INLINE WebPDemuxer* WebPDemuxPartial( 1031e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora const WebPData* data, WebPDemuxState* state) { 1041e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora return WebPDemuxInternal(data, 1, state, WEBP_DEMUX_ABI_VERSION); 1051e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora} 1061e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1071e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Frees memory associated with 'dmux'. 1081e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(void) WebPDemuxDelete(WebPDemuxer* dmux); 1091e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1101e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora//------------------------------------------------------------------------------ 1111e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Data/information extraction. 1121e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1130406ce1417f76f2034833414dcecc9f56253640cVikas Aroratypedef enum WebPFormatFeature { 1141e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WEBP_FF_FORMAT_FLAGS, // Extended format flags present in the 'VP8X' chunk. 1151e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WEBP_FF_CANVAS_WIDTH, 1161e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WEBP_FF_CANVAS_HEIGHT, 1171e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WEBP_FF_LOOP_COUNT, 1181e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WEBP_FF_BACKGROUND_COLOR, 1191e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WEBP_FF_FRAME_COUNT // Number of frames present in the demux object. 1201e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // In case of a partial demux, this is the number of 1211e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // frames seen so far, with the last frame possibly 1221e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // being partial. 1230406ce1417f76f2034833414dcecc9f56253640cVikas Arora} WebPFormatFeature; 1241e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1251e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Get the 'feature' value from the 'dmux'. 1261e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial() 1271e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// returned a state > WEBP_DEMUX_PARSING_HEADER. 1281e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(uint32_t) WebPDemuxGetI( 1291e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora const WebPDemuxer* dmux, WebPFormatFeature feature); 1301e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1311e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora//------------------------------------------------------------------------------ 1321e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Frame iteration. 1331e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1341e7bf8805bd030c19924a5306837ecd72c295751Vikas Arorastruct WebPIterator { 1351e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int frame_num; 1361e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int num_frames; // equivalent to WEBP_FF_FRAME_COUNT. 1371e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int fragment_num; 1381e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int num_fragments; 1391e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int x_offset, y_offset; // offset relative to the canvas. 1401e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int width, height; // dimensions of this frame or fragment. 1411e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int duration; // display duration in milliseconds. 1421e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WebPMuxAnimDispose dispose_method; // dispose method for the frame. 1431e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int complete; // true if 'fragment' contains a full frame. partial images 1441e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // may still be decoded with the WebP incremental decoder. 1451e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WebPData fragment; // The frame or fragment given by 'frame_num' and 1461e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // 'fragment_num'. 1475807b79d0acff7f1bc35c01da54dd51541049137Vikas Arora int has_alpha; // True if the frame or fragment contains transparency. 1485807b79d0acff7f1bc35c01da54dd51541049137Vikas Arora WebPMuxAnimBlend blend_method; // Blend operation for the frame. 1491e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1505807b79d0acff7f1bc35c01da54dd51541049137Vikas Arora uint32_t pad[2]; // padding for later use. 1511e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora void* private_; // for internal use only. 1521e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora}; 1531e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1541e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Retrieves frame 'frame_number' from 'dmux'. 1551e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// 'iter->fragment' points to the first fragment on return from this function. 1568b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora// Individual fragments may be extracted using WebPDemuxSelectFragment(). 1571e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Setting 'frame_number' equal to 0 will return the last frame of the image. 1581e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns false if 'dmux' is NULL or frame 'frame_number' is not present. 1591e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Call WebPDemuxReleaseIterator() when use of the iterator is complete. 1601e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// NOTE: 'dmux' must persist for the lifetime of 'iter'. 1611e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxGetFrame( 1621e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora const WebPDemuxer* dmux, int frame_number, WebPIterator* iter); 1631e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1641e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Sets 'iter->fragment' to point to the next ('iter->frame_num' + 1) or 1651e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// previous ('iter->frame_num' - 1) frame. These functions do not loop. 1661e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns true on success, false otherwise. 1671e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxNextFrame(WebPIterator* iter); 1681e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxPrevFrame(WebPIterator* iter); 1691e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1701e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Sets 'iter->fragment' to reflect fragment number 'fragment_num'. 1711e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns true if fragment 'fragment_num' is present, false otherwise. 1721e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxSelectFragment(WebPIterator* iter, int fragment_num); 1731e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1741e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Releases any memory associated with 'iter'. 1751e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Must be called before any subsequent calls to WebPDemuxGetChunk() on the same 1761e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// iter. Also, must be called before destroying the associated WebPDemuxer with 1771e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// WebPDemuxDelete(). 1781e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(void) WebPDemuxReleaseIterator(WebPIterator* iter); 1791e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1801e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora//------------------------------------------------------------------------------ 1811e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Chunk iteration. 1821e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1831e7bf8805bd030c19924a5306837ecd72c295751Vikas Arorastruct WebPChunkIterator { 1841e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // The current and total number of chunks with the fourcc given to 1851e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora // WebPDemuxGetChunk(). 1861e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int chunk_num; 1871e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora int num_chunks; 1881e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WebPData chunk; // The payload of the chunk. 1891e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1901e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora uint32_t pad[6]; // padding for later use 1911e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora void* private_; 1921e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora}; 1931e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 1941e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Retrieves the 'chunk_number' instance of the chunk with id 'fourcc' from 1951e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// 'dmux'. 1961e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// 'fourcc' is a character array containing the fourcc of the chunk to return, 1971e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// e.g., "ICCP", "XMP ", "EXIF", etc. 1981e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Setting 'chunk_number' equal to 0 will return the last chunk in a set. 1991e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns true if the chunk is found, false otherwise. Image related chunk 2001e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// payloads are accessed through WebPDemuxGetFrame() and related functions. 2011e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Call WebPDemuxReleaseChunkIterator() when use of the iterator is complete. 2021e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// NOTE: 'dmux' must persist for the lifetime of the iterator. 2031e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxGetChunk(const WebPDemuxer* dmux, 2041e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora const char fourcc[4], int chunk_number, 2051e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora WebPChunkIterator* iter); 2061e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 2071e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Sets 'iter->chunk' to point to the next ('iter->chunk_num' + 1) or previous 2081e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// ('iter->chunk_num' - 1) chunk. These functions do not loop. 2091e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Returns true on success, false otherwise. 2101e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxNextChunk(WebPChunkIterator* iter); 2111e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(int) WebPDemuxPrevChunk(WebPChunkIterator* iter); 2121e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 2131e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Releases any memory associated with 'iter'. 2141e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// Must be called before destroying the associated WebPDemuxer with 2151e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora// WebPDemuxDelete(). 2161e7bf8805bd030c19924a5306837ecd72c295751Vikas AroraWEBP_EXTERN(void) WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter); 2171e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 2181e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora//------------------------------------------------------------------------------ 2191e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 2208b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora#ifdef __cplusplus 2211e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora} // extern "C" 2221e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora#endif 2231e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora 2241e7bf8805bd030c19924a5306837ecd72c295751Vikas Arora#endif /* WEBP_WEBP_DEMUX_H_ */ 225