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* This file is part of FFmpeg.
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* @file libavutil/fifo.h
* a very simple circular buffer FIFO implementation
#include <stdint.h>
#include "avutil.h"
#include "common.h"
typedef struct AVFifoBuffer {
uint8_t *buffer;
uint8_t *rptr, *wptr, *end;
uint32_t rndx, wndx;
} AVFifoBuffer;
* Initializes an AVFifoBuffer.
* @param size of FIFO
* @return AVFifoBuffer or NULL if mem allocation failure
AVFifoBuffer *av_fifo_alloc(unsigned int size);
* Frees an AVFifoBuffer.
* @param *f AVFifoBuffer to free
void av_fifo_free(AVFifoBuffer *f);
* Resets the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
* @param *f AVFifoBuffer to reset
void av_fifo_reset(AVFifoBuffer *f);
* Returns the amount of data in bytes in the AVFifoBuffer, that is the
* amount of data you can read from it.
* @param *f AVFifoBuffer to read from
* @return size
int av_fifo_size(AVFifoBuffer *f);
* Feeds data from an AVFifoBuffer to a user-supplied callback.
* @param *f AVFifoBuffer to read from
* @param buf_size number of bytes to read
* @param *func generic read function
* @param *dest data destination
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
* Feeds data from a user-supplied callback to an AVFifoBuffer.
* @param *f AVFifoBuffer to write to
* @param *src data source
* @param size number of bytes to write
* @param *func generic write function; the first parameter is src,
* the second is dest_buf, the third is dest_buf_size.
* func must return the number of bytes written to dest_buf, or <= 0 to
* indicate no more data available to write.
* If func is NULL, src is interpreted as a simple byte array for source data.
* @return the number of bytes written to the FIFO
int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
* Resizes an AVFifoBuffer.
* @param *f AVFifoBuffer to resize
* @param size new AVFifoBuffer size in bytes
* @return <0 for failure, >=0 otherwise
int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
* Reads and discards the specified amount of data from an AVFifoBuffer.
* @param *f AVFifoBuffer to read from
* @param size amount of data to read in bytes
void av_fifo_drain(AVFifoBuffer *f, int size);
static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
uint8_t *ptr = f->rptr + offs;
if (ptr >= f->end)
ptr -= f->end - f->buffer;
return *ptr;
#endif /* AVUTIL_FIFO_H */