PeerStreamer

/*

 * a very simple circular buffer FIFO implementation

 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard

 * Copyright (c) 2006 Roman Shaposhnik

 *

 * 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

 */

#include "common.h"

#include "fifo.h"

AVFifoBuffer *av_fifo_alloc(unsigned int size)

{

    AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));

    if(!f)

        return NULL;

    f->buffer = av_malloc(size);

    f->end = f->buffer + size;

    av_fifo_reset(f);

    if (!f->buffer)

        av_freep(&f);

    return f;

}

void av_fifo_free(AVFifoBuffer *f)

{

    if(f){

        av_freep(&f->buffer);

        av_free(f);

    }

}

void av_fifo_reset(AVFifoBuffer *f)

{

    f->wptr = f->rptr = f->buffer;

    f->wndx = f->rndx = 0;

}

int av_fifo_size(AVFifoBuffer *f)

{

    return (uint32_t)(f->wndx - f->rndx);

}

int av_fifo_space(AVFifoBuffer *f)

{

    return f->end - f->buffer - av_fifo_size(f);

}

int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {

    unsigned int old_size= f->end - f->buffer;

    if(old_size < new_size){

        int len= av_fifo_size(f);

        AVFifoBuffer *f2= av_fifo_alloc(new_size);

        if (!f2)

            return -1;

        av_fifo_generic_read(f, f2->buffer, len, NULL);

        f2->wptr += len;

        f2->wndx += len;

        av_free(f->buffer);

        *f= *f2;

        av_free(f2);

    }

    return 0;

}

// src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)

int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))

{

    int total = size;

    do {

        int len = FFMIN(f->end - f->wptr, size);

        if(func) {

            if(func(src, f->wptr, len) <= 0)

                break;

        } else {

            memcpy(f->wptr, src, len);

            src = (uint8_t*)src + len;

        }

// Write memory barrier needed for SMP here in theory

        f->wptr += len;

        if (f->wptr >= f->end)

            f->wptr = f->buffer;

        f->wndx += len;

        size -= len;

    } while (size > 0);

    return total - size;

}

int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))

{

// Read memory barrier needed for SMP here in theory

    do {

        int len = FFMIN(f->end - f->rptr, buf_size);

        if(func) func(dest, f->rptr, len);

        else{

            memcpy(dest, f->rptr, len);

            dest = (uint8_t*)dest + len;

        }

// memory barrier needed for SMP here in theory

        av_fifo_drain(f, len);

        buf_size -= len;

    } while (buf_size > 0);

    return 0;

}

/** Discard data from the FIFO. */

void av_fifo_drain(AVFifoBuffer *f, int size)

{

    f->rptr += size;

    if (f->rptr >= f->end)

        f->rptr -= f->end - f->buffer;

    f->rndx += size;

}