/*

 * 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;

}

#if FF_API_AV_FIFO_PEEK

/**

 * @deprecated Use av_fifo_peek2() instead.

 */

attribute_deprecated

static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)

{

    return *av_fifo_peek2(f, offs);

}

#endif

#endif /* AVUTIL_FIFO_H */