aboutsummaryrefslogtreecommitdiffstats
path: root/libavutil/fifo.h
blob: 849b9a6b813e16cafbfad334c940a5ef9b3ca0af (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * a very simple circular buffer FIFO implementation
 */

#ifndef AVUTIL_FIFO_H
#define AVUTIL_FIFO_H

#include <stdint.h>
#include "avutil.h"
#include "attributes.h"

typedef struct AVFifoBuffer {
    uint8_t *buffer;
    uint8_t *rptr, *wptr, *end;
    uint32_t rndx, wndx;
} AVFifoBuffer;

/**
 * Initialize an AVFifoBuffer.
 * @param size of FIFO
 * @return AVFifoBuffer or NULL in case of memory allocation failure
 */
AVFifoBuffer *av_fifo_alloc(unsigned int size);

/**
 * Free an AVFifoBuffer.
 * @param f AVFifoBuffer to free
 */
void av_fifo_free(AVFifoBuffer *f);

/**
 * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
 * @param f AVFifoBuffer to reset
 */
void av_fifo_reset(AVFifoBuffer *f);

/**
 * Return the amount of data in bytes in the AVFifoBuffer, that is the
 * amount of data you can read from it.
 * @param f AVFifoBuffer to read from
 * @return size
 */
int av_fifo_size(AVFifoBuffer *f);

/**
 * Return the amount of space in bytes in the AVFifoBuffer, that is the
 * amount of data you can write into it.
 * @param f AVFifoBuffer to write into
 * @return size
 */
int av_fifo_space(AVFifoBuffer *f);

/**
 * Feed data from an AVFifoBuffer to a user-supplied callback.
 * @param f AVFifoBuffer to read from
 * @param buf_size number of bytes to read
 * @param func generic read function
 * @param dest data destination
 */
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));

/**
 * Feed data from a user-supplied callback to an AVFifoBuffer.
 * @param f AVFifoBuffer to write to
 * @param src data source; non-const since it may be used as a
 * modifiable context by the function defined in func
 * @param size number of bytes to write
 * @param func generic write function; the first parameter is src,
 * the second is dest_buf, the third is dest_buf_size.
 * func must return the number of bytes written to dest_buf, or <= 0 to
 * indicate no more data available to write.
 * If func is NULL, src is interpreted as a simple byte array for source data.
 * @return the number of bytes written to the FIFO
 */
int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));

/**
 * Resize an AVFifoBuffer.
 * In case of reallocation failure, the old FIFO is kept unchanged.
 *
 * @param f AVFifoBuffer to resize
 * @param size new AVFifoBuffer size in bytes
 * @return <0 for failure, >=0 otherwise
 */
int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);

/**
 * Enlarge an AVFifoBuffer.
 * In case of reallocation failure, the old FIFO is kept unchanged.
 * The new fifo size may be larger than the requested size.
 *
 * @param f AVFifoBuffer to resize
 * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
 * @return <0 for failure, >=0 otherwise
 */
int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);

/**
 * Read and discard the specified amount of data from an AVFifoBuffer.
 * @param f AVFifoBuffer to read from
 * @param size amount of data to read in bytes
 */
void av_fifo_drain(AVFifoBuffer *f, int size);

/**
 * Return a pointer to the data stored in a FIFO buffer at a certain offset.
 * The FIFO buffer is not modified.
 *
 * @param f    AVFifoBuffer to peek at, f must be non-NULL
 * @param offs an offset in bytes, its absolute value must be less
 *             than the used buffer size or the returned pointer will
 *             point outside to the buffer data.
 *             The used buffer size can be checked with av_fifo_size().
 */
static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
{
    uint8_t *ptr = f->rptr + offs;
    if (ptr >= f->end)
        ptr = f->buffer + (ptr - f->end);
    else if (ptr < f->buffer)
        ptr = f->end - (f->buffer - ptr);
    return ptr;
}

#endif /* AVUTIL_FIFO_H */