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/**
20 * @file
21 * a very simple circular buffer FIFO implementation
22 */
23
24#ifndef AVUTIL_FIFO_H
25#define AVUTIL_FIFO_H
26
27#include <stdint.h>
28
29typedef struct AVFifoBuffer {
30    uint8_t *buffer;
31    uint8_t *rptr, *wptr, *end;
32    uint32_t rndx, wndx;
33} AVFifoBuffer;
34
35/**
36 * Initializes an AVFifoBuffer.
37 * @param size of FIFO
38 * @return AVFifoBuffer or NULL in case of memory allocation failure
39 */
40AVFifoBuffer *av_fifo_alloc(unsigned int size);
41
42/**
43 * Frees an AVFifoBuffer.
44 * @param *f AVFifoBuffer to free
45 */
46void av_fifo_free(AVFifoBuffer *f);
47
48/**
49 * Resets the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
50 * @param *f AVFifoBuffer to reset
51 */
52void av_fifo_reset(AVFifoBuffer *f);
53
54/**
55 * Returns the amount of data in bytes in the AVFifoBuffer, that is the
56 * amount of data you can read from it.
57 * @param *f AVFifoBuffer to read from
58 * @return size
59 */
60int av_fifo_size(AVFifoBuffer *f);
61
62/**
63 * Returns the amount of space in bytes in the AVFifoBuffer, that is the
64 * amount of data you can write into it.
65 * @param *f AVFifoBuffer to write into
66 * @return size
67 */
68int av_fifo_space(AVFifoBuffer *f);
69
70/**
71 * Feeds data from an AVFifoBuffer to a user-supplied callback.
72 * @param *f AVFifoBuffer to read from
73 * @param buf_size number of bytes to read
74 * @param *func generic read function
75 * @param *dest data destination
76 */
77int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
78
79/**
80 * Feeds data from a user-supplied callback to an AVFifoBuffer.
81 * @param *f AVFifoBuffer to write to
82 * @param *src data source; non-const since it may be used as a
83 * modifiable context by the function defined in func
84 * @param size number of bytes to write
85 * @param *func generic write function; the first parameter is src,
86 * the second is dest_buf, the third is dest_buf_size.
87 * func must return the number of bytes written to dest_buf, or <= 0 to
88 * indicate no more data available to write.
89 * If func is NULL, src is interpreted as a simple byte array for source data.
90 * @return the number of bytes written to the FIFO
91 */
92int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
93
94/**
95 * Resizes an AVFifoBuffer.
96 * @param *f AVFifoBuffer to resize
97 * @param size new AVFifoBuffer size in bytes
98 * @return <0 for failure, >=0 otherwise
99 */
100int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
101
102/**
103 * Reads and discards the specified amount of data from an AVFifoBuffer.
104 * @param *f AVFifoBuffer to read from
105 * @param size amount of data to read in bytes
106 */
107void av_fifo_drain(AVFifoBuffer *f, int size);
108
109static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
110{
111    uint8_t *ptr = f->rptr + offs;
112    if (ptr >= f->end)
113        ptr -= f->end - f->buffer;
114    return *ptr;
115}
116#endif /* AVUTIL_FIFO_H */
117