2 * This file is part of FFmpeg.
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.
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.
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
21 * a very simple circular buffer FIFO implementation
29 #include "attributes.h"
31 typedef struct AVFifoBuffer {
33 uint8_t *rptr, *wptr, *end;
38 * Initialize an AVFifoBuffer.
40 * @return AVFifoBuffer or NULL in case of memory allocation failure
42 AVFifoBuffer *av_fifo_alloc(unsigned int size);
45 * Free an AVFifoBuffer.
46 * @param f AVFifoBuffer to free
48 void av_fifo_free(AVFifoBuffer *f);
51 * Free an AVFifoBuffer and reset pointer to NULL.
52 * @param f AVFifoBuffer to free
54 void av_fifo_freep(AVFifoBuffer **f);
57 * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
58 * @param f AVFifoBuffer to reset
60 void av_fifo_reset(AVFifoBuffer *f);
63 * Return the amount of data in bytes in the AVFifoBuffer, that is the
64 * amount of data you can read from it.
65 * @param f AVFifoBuffer to read from
68 int av_fifo_size(FF_CONST_AVUTIL53 AVFifoBuffer *f);
71 * Return the amount of space in bytes in the AVFifoBuffer, that is the
72 * amount of data you can write into it.
73 * @param f AVFifoBuffer to write into
76 int av_fifo_space(FF_CONST_AVUTIL53 AVFifoBuffer *f);
79 * Feed data from an AVFifoBuffer to a user-supplied callback.
80 * @param f AVFifoBuffer to read from
81 * @param buf_size number of bytes to read
82 * @param func generic read function
83 * @param dest data destination
85 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
88 * Feed data from a user-supplied callback to an AVFifoBuffer.
89 * @param f AVFifoBuffer to write to
90 * @param src data source; non-const since it may be used as a
91 * modifiable context by the function defined in func
92 * @param size number of bytes to write
93 * @param func generic write function; the first parameter is src,
94 * the second is dest_buf, the third is dest_buf_size.
95 * func must return the number of bytes written to dest_buf, or <= 0 to
96 * indicate no more data available to write.
97 * If func is NULL, src is interpreted as a simple byte array for source data.
98 * @return the number of bytes written to the FIFO
100 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
103 * Resize an AVFifoBuffer.
104 * In case of reallocation failure, the old FIFO is kept unchanged.
106 * @param f AVFifoBuffer to resize
107 * @param size new AVFifoBuffer size in bytes
108 * @return <0 for failure, >=0 otherwise
110 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
113 * Enlarge an AVFifoBuffer.
114 * In case of reallocation failure, the old FIFO is kept unchanged.
115 * The new fifo size may be larger than the requested size.
117 * @param f AVFifoBuffer to resize
118 * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
119 * @return <0 for failure, >=0 otherwise
121 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
124 * Read and discard the specified amount of data from an AVFifoBuffer.
125 * @param f AVFifoBuffer to read from
126 * @param size amount of data to read in bytes
128 void av_fifo_drain(AVFifoBuffer *f, int size);
131 * Return a pointer to the data stored in a FIFO buffer at a certain offset.
132 * The FIFO buffer is not modified.
134 * @param f AVFifoBuffer to peek at, f must be non-NULL
135 * @param offs an offset in bytes, its absolute value must be less
136 * than the used buffer size or the returned pointer will
137 * point outside to the buffer data.
138 * The used buffer size can be checked with av_fifo_size().
140 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
142 uint8_t *ptr = f->rptr + offs;
144 ptr = f->buffer + (ptr - f->end);
145 else if (ptr < f->buffer)
146 ptr = f->end - (f->buffer - ptr);
150 #endif /* AVUTIL_FIFO_H */