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
20 * @file libavutil/fifo.h
21 * a very simple circular buffer FIFO implementation
31 typedef struct AVFifoBuffer {
33 uint8_t *rptr, *wptr, *end;
38 * Initializes an AVFifoBuffer.
40 * @return AVFifoBuffer or NULL if mem allocation failure
42 AVFifoBuffer *av_fifo_alloc(unsigned int size);
45 * Frees an AVFifoBuffer.
46 * @param *f AVFifoBuffer to free
48 void av_fifo_free(AVFifoBuffer *f);
51 * Returns the amount of data in bytes in the AVFifoBuffer, that is the
52 * amount of data you can read from it.
53 * @param *f AVFifoBuffer to read from
56 int av_fifo_size(AVFifoBuffer *f);
59 * Feeds data from an AVFifoBuffer to a user-supplied callback.
60 * @param *f AVFifoBuffer to read from
61 * @param buf_size number of bytes to read
62 * @param *func generic read function
63 * @param *dest data destination
65 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest);
68 * Feeds data from a user-supplied callback to an AVFifoBuffer.
69 * @param *f AVFifoBuffer to write to
70 * @param *src data source
71 * @param size number of bytes to write
72 * @param *func generic write function; the first parameter is src,
73 * the second is dest_buf, the third is dest_buf_size.
74 * func must return the number of bytes written to dest_buf, or <= 0 to
75 * indicate no more data available to write.
76 * If func is NULL, src is interpreted as a simple byte array for source data.
77 * @return the number of bytes written to the FIFO
79 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
82 * Resizes an AVFifoBuffer.
83 * @param *f AVFifoBuffer to resize
84 * @param size new AVFifoBuffer size in bytes
85 * @return <0 for failure, >=0 otherwise
87 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
90 * Reads and discards the specified amount of data from an AVFifoBuffer.
91 * @param *f AVFifoBuffer to read from
92 * @param size amount of data to read in bytes
94 void av_fifo_drain(AVFifoBuffer *f, int size);
96 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
98 uint8_t *ptr = f->rptr + offs;
100 ptr -= f->end - f->buffer;
103 #endif /* AVUTIL_FIFO_H */