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/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* a very simple circular buffer FIFO implementation
*/
#ifndef AVUTIL_FIFO_H
#define AVUTIL_FIFO_H
#include <stdint.h>
#include "avutil.h"
#include "attributes.h"
typedef struct AVFifoBuffer {
uint8_t *buffer;
uint8_t *rptr, *wptr, *end;
uint32_t rndx, wndx;
} AVFifoBuffer;
/**
* Initialize an AVFifoBuffer.
* @param size of FIFO
* @return AVFifoBuffer or NULL in case of memory allocation failure
*/
AVFifoBuffer *av_fifo_alloc(unsigned int size);
/**
* Free an AVFifoBuffer.
* @param f AVFifoBuffer to free
*/
void av_fifo_free(AVFifoBuffer *f);
/**
* Reset 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);
/**
* Return 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);
/**
* Return the amount of space in bytes in the AVFifoBuffer, that is the
* amount of data you can write into it.
* @param f AVFifoBuffer to write into
* @return size
*/
int av_fifo_space(AVFifoBuffer *f);
/**
* Feed 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));
/**
* Feed data from a user-supplied callback to an AVFifoBuffer.
* @param f AVFifoBuffer to write to
* @param src data source; non-const since it may be used as a
* modifiable context by the function defined in func
* @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));
/**
* Resize 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);
/**
* Read and discard 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);
/**
* Return a pointer to the data stored in a FIFO buffer at a certain offset.
* The FIFO buffer is not modified.
*
* @param f AVFifoBuffer to peek at, f must be non-NULL
* @param offs an offset in bytes, its absolute value must be less
* than the used buffer size or the returned pointer will
* point outside to the buffer data.
* The used buffer size can be checked with av_fifo_size().
*/
static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
{
uint8_t *ptr = f->rptr + offs;
if (ptr >= f->end)
ptr = f->buffer + (ptr - f->end);
else if (ptr < f->buffer)
ptr = f->end - (f->buffer - ptr);
return ptr;
}
#endif /* AVUTIL_FIFO_H */
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