Mercurial > mm7

comparison lib/libavutil/fifo.h @ 2134:992d2e6f907d

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
preparation for libavcodec
author zipi
date Tue, 31 Dec 2013 14:52:14 +0000
parents
children
comparison
equal deleted inserted replaced
2133:e378232bfd36 2134:992d2e6f907d
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 #include "avutil.h"
29 #include "attributes.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 * Initialize an AVFifoBuffer.
39 * @param size of FIFO
40 * @return AVFifoBuffer or NULL in case of memory allocation failure
41 */
42 AVFifoBuffer *av_fifo_alloc(unsigned int size);
43
44 /**
45 * Free an AVFifoBuffer.
46 * @param f AVFifoBuffer to free
47 */
48 void av_fifo_free(AVFifoBuffer *f);
49
50 /**
51 * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
52 * @param f AVFifoBuffer to reset
53 */
54 void av_fifo_reset(AVFifoBuffer *f);
55
56 /**
57 * Return the amount of data in bytes in the AVFifoBuffer, that is the
58 * amount of data you can read from it.
59 * @param f AVFifoBuffer to read from
60 * @return size
61 */
62 int av_fifo_size(AVFifoBuffer *f);
63
64 /**
65 * Return the amount of space in bytes in the AVFifoBuffer, that is the
66 * amount of data you can write into it.
67 * @param f AVFifoBuffer to write into
68 * @return size
69 */
70 int av_fifo_space(AVFifoBuffer *f);
71
72 /**
73 * Feed data from an AVFifoBuffer to a user-supplied callback.
74 * @param f AVFifoBuffer to read from
75 * @param buf_size number of bytes to read
76 * @param func generic read function
77 * @param dest data destination
78 */
79 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
80
81 /**
82 * Feed data from a user-supplied callback to an AVFifoBuffer.
83 * @param f AVFifoBuffer to write to
84 * @param src data source; non-const since it may be used as a
85 * modifiable context by the function defined in func
86 * @param size number of bytes to write
87 * @param func generic write function; the first parameter is src,
88 * the second is dest_buf, the third is dest_buf_size.
89 * func must return the number of bytes written to dest_buf, or <= 0 to
90 * indicate no more data available to write.
91 * If func is NULL, src is interpreted as a simple byte array for source data.
92 * @return the number of bytes written to the FIFO
93 */
94 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
95
96 /**
97 * Resize an AVFifoBuffer.
98 * In case of reallocation failure, the old FIFO is kept unchanged.
99 *
100 * @param f AVFifoBuffer to resize
101 * @param size new AVFifoBuffer size in bytes
102 * @return <0 for failure, >=0 otherwise
103 */
104 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
105
106 /**
107 * Enlarge an AVFifoBuffer.
108 * In case of reallocation failure, the old FIFO is kept unchanged.
109 * The new fifo size may be larger than the requested size.
110 *
111 * @param f AVFifoBuffer to resize
112 * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
113 * @return <0 for failure, >=0 otherwise
114 */
115 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
116
117 /**
118 * Read and discard the specified amount of data from an AVFifoBuffer.
119 * @param f AVFifoBuffer to read from
120 * @param size amount of data to read in bytes
121 */
122 void av_fifo_drain(AVFifoBuffer *f, int size);
123
124 /**
125 * Return a pointer to the data stored in a FIFO buffer at a certain offset.
126 * The FIFO buffer is not modified.
127 *
128 * @param f AVFifoBuffer to peek at, f must be non-NULL
129 * @param offs an offset in bytes, its absolute value must be less
130 * than the used buffer size or the returned pointer will
131 * point outside to the buffer data.
132 * The used buffer size can be checked with av_fifo_size().
133 */
134 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
135 {
136 uint8_t *ptr = f->rptr + offs;
137 if (ptr >= f->end)
138 ptr = f->buffer + (ptr - f->end);
139 else if (ptr < f->buffer)
140 ptr = f->end - (f->buffer - ptr);
141 return ptr;
142 }
143
144 #endif /* AVUTIL_FIFO_H */