Try to fix the 1 byte cannot be used issue.
[libav.git] / libavutil / fifo.h
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 libavutil/fifo.h
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 #include "avutil.h"
29 #include "common.h"
30
31 typedef struct AVFifoBuffer {
32 uint8_t *buffer;
33 uint8_t *rptr, *wptr, *end;
34 uint32_t rndx, wndx;
35 } AVFifoBuffer;
36
37 /**
38 * Initializes an AVFifoBuffer.
39 * @param *f AVFifoBuffer to initialize
40 * @param size of FIFO
41 * @return <0 for failure >=0 otherwise
42 */
43 int av_fifo_init(AVFifoBuffer *f, unsigned int size);
44
45 /**
46 * Frees an AVFifoBuffer.
47 * @param *f AVFifoBuffer to free
48 */
49 void av_fifo_free(AVFifoBuffer *f);
50
51 /**
52 * Returns the amount of data in bytes in the AVFifoBuffer, that is the
53 * amount of data you can read from it.
54 * @param *f AVFifoBuffer to read from
55 * @return size
56 */
57 int av_fifo_size(AVFifoBuffer *f);
58
59 /**
60 * Reads data from an AVFifoBuffer.
61 * @param *f AVFifoBuffer to read from
62 * @param *buf data destination
63 * @param buf_size number of bytes to read
64 */
65 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size);
66
67 /**
68 * Feeds data from an AVFifoBuffer to a user-supplied callback.
69 * @param *f AVFifoBuffer to read from
70 * @param buf_size number of bytes to read
71 * @param *func generic read function
72 * @param *dest data destination
73 */
74 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
75
76 #if LIBAVUTIL_VERSION_MAJOR < 50
77 /**
78 * Writes data into an AVFifoBuffer.
79 * @param *f AVFifoBuffer to write to
80 * @param *buf data source
81 * @param size data size
82 */
83 attribute_deprecated void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
84 #endif
85
86 /**
87 * Feeds data from a user-supplied callback to an AVFifoBuffer.
88 * @param *f AVFifoBuffer to write to
89 * @param *src data source
90 * @param size number of bytes to write
91 * @param *func generic write function; the first parameter is src,
92 * the second is dest_buf, the third is dest_buf_size.
93 * func must return the number of bytes written to dest_buf, or <= 0 to
94 * indicate no more data available to write.
95 * If func is NULL, src is interpreted as a simple byte array for source data.
96 * @return the number of bytes written to the FIFO
97 */
98 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
99
100 #if LIBAVUTIL_VERSION_MAJOR < 50
101 /**
102 * Resizes an AVFifoBuffer.
103 * @param *f AVFifoBuffer to resize
104 * @param size new AVFifoBuffer size in bytes
105 * @see av_fifo_realloc2()
106 */
107 attribute_deprecated void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
108 #endif
109
110 /**
111 * Resizes an AVFifoBuffer.
112 * @param *f AVFifoBuffer to resize
113 * @param size new AVFifoBuffer size in bytes
114 * @return <0 for failure, >=0 otherwise
115 */
116 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
117
118 /**
119 * Reads and discards the specified amount of data from an AVFifoBuffer.
120 * @param *f AVFifoBuffer to read from
121 * @param size amount of data to read in bytes
122 */
123 void av_fifo_drain(AVFifoBuffer *f, int size);
124
125 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
126 {
127 uint8_t *ptr = f->rptr + offs;
128 if (ptr >= f->end)
129 ptr -= f->end - f->buffer;
130 return *ptr;
131 }
132 #endif /* AVUTIL_FIFO_H */