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 was av_realloc()ed, so it is reallocatable.
30 */
31#define BUFFER_FLAG_REALLOCATABLE (1 << 0)
32/**
33 * The AVBuffer structure is part of a larger structure
34 * and should not be freed.
35 */
36#define BUFFER_FLAG_NO_FREE       (1 << 1)
37
38struct AVBuffer {
39    uint8_t *data; /**< data described by this buffer */
40    size_t size; /**< size of data in bytes */
41
42    /**
43     *  number of existing AVBufferRef instances referring to this buffer
44     */
45    atomic_uint refcount;
46
47    /**
48     * a callback for freeing the data
49     */
50    void (*free)(void *opaque, uint8_t *data);
51
52    /**
53     * an opaque pointer, to be used by the freeing callback
54     */
55    void *opaque;
56
57    /**
58     * A combination of AV_BUFFER_FLAG_*
59     */
60    int flags;
61
62    /**
63     * A combination of BUFFER_FLAG_*
64     */
65    int flags_internal;
66};
67
68typedef struct BufferPoolEntry {
69    uint8_t *data;
70
71    /*
72     * Backups of the original opaque/free of the AVBuffer corresponding to
73     * data. They will be used to free the buffer when the pool is freed.
74     */
75    void *opaque;
76    void (*free)(void *opaque, uint8_t *data);
77
78    AVBufferPool *pool;
79    struct BufferPoolEntry *next;
80
81    /*
82     * An AVBuffer structure to (re)use as AVBuffer for subsequent uses
83     * of this BufferPoolEntry.
84     */
85    AVBuffer buffer;
86} BufferPoolEntry;
87
88struct AVBufferPool {
89    AVMutex mutex;
90    BufferPoolEntry *pool;
91
92    /*
93     * This is used to track when the pool is to be freed.
94     * The pointer to the pool itself held by the caller is considered to
95     * be one reference. Each buffer requested by the caller increases refcount
96     * by one, returning the buffer to the pool decreases it by one.
97     * refcount reaches zero when the buffer has been uninited AND all the
98     * buffers have been released, then it's safe to free the pool and all
99     * the buffers in it.
100     */
101    atomic_uint refcount;
102
103    size_t size;
104    void *opaque;
105    AVBufferRef* (*alloc)(size_t size);
106    AVBufferRef* (*alloc2)(void *opaque, size_t size);
107    void         (*pool_free)(void *opaque);
108};
109
110#endif /* AVUTIL_BUFFER_INTERNAL_H */
111