path: root/libavutil/buffer_internal.h (plain)
blob: 54b67047e5e54d8ea54ca0567c067ea42200832a

1	/*
2	* This file is part of FFmpeg.
3	*
4	* FFmpeg is free software; you can redistribute it and/or
5	* modify it under the terms of the GNU Lesser General Public
6	* License as published by the Free Software Foundation; either
7	* version 2.1 of the License, or (at your option) any later version.
8	*
9	* FFmpeg is distributed in the hope that it will be useful,
10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12	* Lesser General Public License for more details.
13	*
14	* You should have received a copy of the GNU Lesser General Public
15	* License along with FFmpeg; if not, write to the Free Software
16	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17	*/
18
19	#ifndef AVUTIL_BUFFER_INTERNAL_H
20	#define AVUTIL_BUFFER_INTERNAL_H
21
22	#include <stdatomic.h>
23	#include <stdint.h>
24
25	#include "buffer.h"
26	#include "thread.h"
27
28	/**
29	* The buffer is always treated as read-only.
30	*/
31	#define BUFFER_FLAG_READONLY (1 << 0)
32	/**
33	* The buffer was av_realloc()ed, so it is reallocatable.
34	*/
35	#define BUFFER_FLAG_REALLOCATABLE (1 << 1)
36
37	struct AVBuffer {
38	uint8_t *data; /**< data described by this buffer */
39	int size; /**< size of data in bytes */
40
41	/**
42	* number of existing AVBufferRef instances referring to this buffer
43	*/
44	atomic_uint refcount;
45
46	/**
47	* a callback for freeing the data
48	*/
49	void (*free)(void *opaque, uint8_t *data);
50
51	/**
52	* an opaque pointer, to be used by the freeing callback
53	*/
54	void *opaque;
55
56	/**
57	* A combination of BUFFER_FLAG_*
58	*/
59	int flags;
60	};
61
62	typedef struct BufferPoolEntry {
63	uint8_t *data;
64
65	/*
66	* Backups of the original opaque/free of the AVBuffer corresponding to
67	* data. They will be used to free the buffer when the pool is freed.
68	*/
69	void *opaque;
70	void (*free)(void *opaque, uint8_t *data);
71
72	AVBufferPool *pool;
73	struct BufferPoolEntry *next;
74	} BufferPoolEntry;
75
76	struct AVBufferPool {
77	AVMutex mutex;
78	BufferPoolEntry *pool;
79
80	/*
81	* This is used to track when the pool is to be freed.
82	* The pointer to the pool itself held by the caller is considered to
83	* be one reference. Each buffer requested by the caller increases refcount
84	* by one, returning the buffer to the pool decreases it by one.
85	* refcount reaches zero when the buffer has been uninited AND all the
86	* buffers have been released, then it's safe to free the pool and all
87	* the buffers in it.
88	*/
89	atomic_uint refcount;
90
91	int size;
92	void *opaque;
93	AVBufferRef* (*alloc)(int size);
94	AVBufferRef* (*alloc2)(void *opaque, int size);
95	void (*pool_free)(void *opaque);
96	};
97
98	#endif /* AVUTIL_BUFFER_INTERNAL_H */
99