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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 |
* 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 FFmpeg; 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. |
* In case of reallocation failure, the old FIFO is kept unchanged. |
* |
* @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); |
|
/** |
* Enlarge an AVFifoBuffer. |
* In case of reallocation failure, the old FIFO is kept unchanged. |
* The new fifo size may be larger than the requested size. |
* |
* @param f AVFifoBuffer to resize |
* @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size() |
* @return <0 for failure, >=0 otherwise |
*/ |
int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space); |
|
/** |
* 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; |
} |
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#endif /* AVUTIL_FIFO_H */ |