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// Copyright (c) 2021, Alliance for Open Media. All rights reserved
//
// This source code is subject to the terms of the BSD 2 Clause License and
// the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
// was not distributed with this source code in the LICENSE file, you can
// obtain it at www.aomedia.org/license/software. If the Alliance for Open
// Media Patent License 1.0 was not distributed with this source code in the
// PATENTS file, you can obtain it at www.aomedia.org/license/patent.
#ifndef AVIFINFO_H_
#define AVIFINFO_H_
#include <stddef.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
//------------------------------------------------------------------------------
typedef enum {
kAvifInfoOk, // The file was correctly parsed and the requested
// information was extracted. It is not guaranteed
// that the input bitstream is a valid complete
// AVIF file.
kAvifInfoNotEnoughData, // The input bitstream was correctly parsed until
// now but bytes are missing. The request should be
// repeated with more input bytes.
kAvifInfoTooComplex, // The input bitstream was correctly parsed until
// now but it is too complex. The parsing was
// stopped to avoid any timeout or crash.
kAvifInfoInvalidFile, // The input bitstream is not a valid AVIF file,
// truncated or not.
} AvifInfoStatus;
typedef struct {
uint32_t width, height; // In number of pixels. Ignores mirror and rotation.
uint32_t bit_depth; // Likely 8, 10 or 12 bits per channel per pixel.
uint32_t num_channels; // Likely 1, 2, 3 or 4 channels:
// (1 monochrome or 3 colors) + (0 or 1 alpha)
uint8_t has_gainmap; // True if a gain map was found.
// Id of the gain map item. Assumes there is at most one. If there are several
// gain map items (e.g. because the main image is tiled and each tile has an
// independent gain map), then this is one of the ids, arbitrarily chosen.
uint8_t gainmap_item_id;
// Start location in bytes of the primary item id, relative to the beginning
// of the given payload. The primary item id is a big endian number stored on
// bytes primary_item_id_location to
// primary_item_id_location+primary_item_id_bytes-1 inclusive.
uint64_t primary_item_id_location;
// Number of bytes of the primary item id.
uint8_t primary_item_id_bytes;
} AvifInfoFeatures;
//------------------------------------------------------------------------------
// Fixed-size input API
// Use this API if a raw byte array of fixed size is available as input.
// Parses the 'data' and returns kAvifInfoOk if it is identified as an AVIF.
// 'data' can be partial but must point to the beginning of the AVIF file.
// The file type can be identified in the first 12 bytes of most AVIF files.
AvifInfoStatus AvifInfoIdentify(const uint8_t* data, size_t data_size);
// Parses the 'data' and returns kAvifInfoOk and its 'features' if it is
// identified as an AVIF file.
// 'data' can be partial but must point to the beginning of the AVIF file.
// The 'features' can be parsed in the first 450 bytes of most AVIF files.
// 'features' are set to 0 unless kAvifInfoOk is returned.
// There is no need to call AvifInfoIdentify() before AvifInfoGetFeatures().
// AvifInfoGetFeatures() parses the file further than AvifInfoIdentify() so it
// is possible that AvifInfoGetFeatures() returns errors while
// AvifInfoIdentify() returns kAvifInfoOk on the same given input bytes.
AvifInfoStatus AvifInfoGetFeatures(const uint8_t* data, size_t data_size,
AvifInfoFeatures* features);
//------------------------------------------------------------------------------
// Streamed input API
// Use this API if the input bytes must be fetched and/or if the AVIF payload
// size is unknown. Implement the two function signatures below and pass them to
// AvifInfoRead*() with a 'stream', which can be anything (file, struct etc.).
// Reads 'num_bytes' from the 'stream'.
// The position in the 'stream' must be advanced by 'num_bytes'.
// Returns a pointer to the 'num_bytes' or null if it cannot be fulfilled.
// The returned data must remain valid until the next read.
typedef const uint8_t* (*read_stream_t)(void* stream, size_t num_bytes);
// Advances the position in the 'stream' by 'num_bytes'.
typedef void (*skip_stream_t)(void* stream, size_t num_bytes);
// Maximum number of bytes requested per read. There is no limit per skip.
#define AVIFINFO_MAX_NUM_READ_BYTES 64
// Same as AvifInfo*() but takes a 'stream' as input. AvifInfo*Stream() does
// not access the 'stream' directly but passes it as is to 'read' and 'skip'.
// 'read' cannot be null. If 'skip' is null, 'read' is called instead.
AvifInfoStatus AvifInfoIdentifyStream(void* stream, read_stream_t read,
skip_stream_t skip);
// Can be called right after AvifInfoIdentifyStream() with the same 'stream'
// object if AvifInfoIdentifyStream() returned kAvifInfoOk.
// Any location-dependent feature such as 'primary_item_id_location' is relative
// to the given 'stream', and must be offset by the number of bytes read or
// skipped during AvifInfoIdentifyStream() if it was called prior to
// AvifInfoGetFeaturesStream() on the same 'stream' object.
// AvifInfoGetFeaturesStream() should only be called if AvifInfoIdentifyStream()
// returned kAvifInfoOk with the same input bytes.
AvifInfoStatus AvifInfoGetFeaturesStream(void* stream, read_stream_t read,
skip_stream_t skip,
AvifInfoFeatures* features);
//------------------------------------------------------------------------------
#ifdef __cplusplus
} // extern "C"
#endif
#endif // AVIFINFO_H_