diff options
Diffstat (limited to 'drivers/webp/demux.h')
| -rw-r--r-- | drivers/webp/demux.h | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/drivers/webp/demux.h b/drivers/webp/demux.h new file mode 100644 index 0000000000..2da3239dd9 --- /dev/null +++ b/drivers/webp/demux.h @@ -0,0 +1,224 @@ +// Copyright 2012 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. +// ----------------------------------------------------------------------------- +// +// Demux API. +// Enables extraction of image and extended format data from WebP files. + +// Code Example: Demuxing WebP data to extract all the frames, ICC profile +// and EXIF/XMP metadata. +/* + WebPDemuxer* demux = WebPDemux(&webp_data); + + uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH); + uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT); + // ... (Get information about the features present in the WebP file). + uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS); + + // ... (Iterate over all frames). + WebPIterator iter; + if (WebPDemuxGetFrame(demux, 1, &iter)) { + do { + // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(), + // ... and get other frame properties like width, height, offsets etc. + // ... see 'struct WebPIterator' below for more info). + } while (WebPDemuxNextFrame(&iter)); + WebPDemuxReleaseIterator(&iter); + } + + // ... (Extract metadata). + WebPChunkIterator chunk_iter; + if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter); + // ... (Consume the ICC profile in 'chunk_iter.chunk'). + WebPDemuxReleaseChunkIterator(&chunk_iter); + if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter); + // ... (Consume the EXIF metadata in 'chunk_iter.chunk'). + WebPDemuxReleaseChunkIterator(&chunk_iter); + if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter); + // ... (Consume the XMP metadata in 'chunk_iter.chunk'). + WebPDemuxReleaseChunkIterator(&chunk_iter); + WebPDemuxDelete(demux); +*/ + +#ifndef WEBP_WEBP_DEMUX_H_ +#define WEBP_WEBP_DEMUX_H_ + +#include "./mux_types.h" + +#ifdef __cplusplus +extern "C" { +#endif + +#define WEBP_DEMUX_ABI_VERSION 0x0101 // MAJOR(8b) + MINOR(8b) + +// Note: forward declaring enumerations is not allowed in (strict) C and C++, +// the types are left here for reference. +// typedef enum WebPDemuxState WebPDemuxState; +// typedef enum WebPFormatFeature WebPFormatFeature; +typedef struct WebPDemuxer WebPDemuxer; +typedef struct WebPIterator WebPIterator; +typedef struct WebPChunkIterator WebPChunkIterator; + +//------------------------------------------------------------------------------ + +// Returns the version number of the demux library, packed in hexadecimal using +// 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507. +WEBP_EXTERN(int) WebPGetDemuxVersion(void); + +//------------------------------------------------------------------------------ +// Life of a Demux object + +typedef enum WebPDemuxState { + WEBP_DEMUX_PARSE_ERROR = -1, // An error occurred while parsing. + WEBP_DEMUX_PARSING_HEADER = 0, // Not enough data to parse full header. + WEBP_DEMUX_PARSED_HEADER = 1, // Header parsing complete, + // data may be available. + WEBP_DEMUX_DONE = 2 // Entire file has been parsed. +} WebPDemuxState; + +// Internal, version-checked, entry point +WEBP_EXTERN(WebPDemuxer*) WebPDemuxInternal( + const WebPData*, int, WebPDemuxState*, int); + +// Parses the full WebP file given by 'data'. +// Returns a WebPDemuxer object on successful parse, NULL otherwise. +static WEBP_INLINE WebPDemuxer* WebPDemux(const WebPData* data) { + return WebPDemuxInternal(data, 0, NULL, WEBP_DEMUX_ABI_VERSION); +} + +// Parses the possibly incomplete WebP file given by 'data'. +// If 'state' is non-NULL it will be set to indicate the status of the demuxer. +// Returns NULL in case of error or if there isn't enough data to start parsing; +// and a WebPDemuxer object on successful parse. +// Note that WebPDemuxer keeps internal pointers to 'data' memory segment. +// If this data is volatile, the demuxer object should be deleted (by calling +// WebPDemuxDelete()) and WebPDemuxPartial() called again on the new data. +// This is usually an inexpensive operation. +static WEBP_INLINE WebPDemuxer* WebPDemuxPartial( + const WebPData* data, WebPDemuxState* state) { + return WebPDemuxInternal(data, 1, state, WEBP_DEMUX_ABI_VERSION); +} + +// Frees memory associated with 'dmux'. +WEBP_EXTERN(void) WebPDemuxDelete(WebPDemuxer* dmux); + +//------------------------------------------------------------------------------ +// Data/information extraction. + +typedef enum WebPFormatFeature { + WEBP_FF_FORMAT_FLAGS, // Extended format flags present in the 'VP8X' chunk. + WEBP_FF_CANVAS_WIDTH, + WEBP_FF_CANVAS_HEIGHT, + WEBP_FF_LOOP_COUNT, + WEBP_FF_BACKGROUND_COLOR, + WEBP_FF_FRAME_COUNT // Number of frames present in the demux object. + // In case of a partial demux, this is the number of + // frames seen so far, with the last frame possibly + // being partial. +} WebPFormatFeature; + +// Get the 'feature' value from the 'dmux'. +// NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial() +// returned a state > WEBP_DEMUX_PARSING_HEADER. +WEBP_EXTERN(uint32_t) WebPDemuxGetI( + const WebPDemuxer* dmux, WebPFormatFeature feature); + +//------------------------------------------------------------------------------ +// Frame iteration. + +struct WebPIterator { + int frame_num; + int num_frames; // equivalent to WEBP_FF_FRAME_COUNT. + int fragment_num; + int num_fragments; + int x_offset, y_offset; // offset relative to the canvas. + int width, height; // dimensions of this frame or fragment. + int duration; // display duration in milliseconds. + WebPMuxAnimDispose dispose_method; // dispose method for the frame. + int complete; // true if 'fragment' contains a full frame. partial images + // may still be decoded with the WebP incremental decoder. + WebPData fragment; // The frame or fragment given by 'frame_num' and + // 'fragment_num'. + int has_alpha; // True if the frame or fragment contains transparency. + WebPMuxAnimBlend blend_method; // Blend operation for the frame. + + uint32_t pad[2]; // padding for later use. + void* private_; // for internal use only. +}; + +// Retrieves frame 'frame_number' from 'dmux'. +// 'iter->fragment' points to the first fragment on return from this function. +// Individual fragments may be extracted using WebPDemuxSelectFragment(). +// Setting 'frame_number' equal to 0 will return the last frame of the image. +// Returns false if 'dmux' is NULL or frame 'frame_number' is not present. +// Call WebPDemuxReleaseIterator() when use of the iterator is complete. +// NOTE: 'dmux' must persist for the lifetime of 'iter'. +WEBP_EXTERN(int) WebPDemuxGetFrame( + const WebPDemuxer* dmux, int frame_number, WebPIterator* iter); + +// Sets 'iter->fragment' to point to the next ('iter->frame_num' + 1) or +// previous ('iter->frame_num' - 1) frame. These functions do not loop. +// Returns true on success, false otherwise. +WEBP_EXTERN(int) WebPDemuxNextFrame(WebPIterator* iter); +WEBP_EXTERN(int) WebPDemuxPrevFrame(WebPIterator* iter); + +// Sets 'iter->fragment' to reflect fragment number 'fragment_num'. +// Returns true if fragment 'fragment_num' is present, false otherwise. +WEBP_EXTERN(int) WebPDemuxSelectFragment(WebPIterator* iter, int fragment_num); + +// Releases any memory associated with 'iter'. +// Must be called before any subsequent calls to WebPDemuxGetChunk() on the same +// iter. Also, must be called before destroying the associated WebPDemuxer with +// WebPDemuxDelete(). +WEBP_EXTERN(void) WebPDemuxReleaseIterator(WebPIterator* iter); + +//------------------------------------------------------------------------------ +// Chunk iteration. + +struct WebPChunkIterator { + // The current and total number of chunks with the fourcc given to + // WebPDemuxGetChunk(). + int chunk_num; + int num_chunks; + WebPData chunk; // The payload of the chunk. + + uint32_t pad[6]; // padding for later use + void* private_; +}; + +// Retrieves the 'chunk_number' instance of the chunk with id 'fourcc' from +// 'dmux'. +// 'fourcc' is a character array containing the fourcc of the chunk to return, +// e.g., "ICCP", "XMP ", "EXIF", etc. +// Setting 'chunk_number' equal to 0 will return the last chunk in a set. +// Returns true if the chunk is found, false otherwise. Image related chunk +// payloads are accessed through WebPDemuxGetFrame() and related functions. +// Call WebPDemuxReleaseChunkIterator() when use of the iterator is complete. +// NOTE: 'dmux' must persist for the lifetime of the iterator. +WEBP_EXTERN(int) WebPDemuxGetChunk(const WebPDemuxer* dmux, + const char fourcc[4], int chunk_number, + WebPChunkIterator* iter); + +// Sets 'iter->chunk' to point to the next ('iter->chunk_num' + 1) or previous +// ('iter->chunk_num' - 1) chunk. These functions do not loop. +// Returns true on success, false otherwise. +WEBP_EXTERN(int) WebPDemuxNextChunk(WebPChunkIterator* iter); +WEBP_EXTERN(int) WebPDemuxPrevChunk(WebPChunkIterator* iter); + +// Releases any memory associated with 'iter'. +// Must be called before destroying the associated WebPDemuxer with +// WebPDemuxDelete(). +WEBP_EXTERN(void) WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter); + +//------------------------------------------------------------------------------ + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif /* WEBP_WEBP_DEMUX_H_ */ |