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/*
* a very simple circular buffer FIFO implementation
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
* Copyright (c) 2006 Roman Shaposhnik
*
* 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
*/
#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_free(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;
}
#ifdef TEST
int main(void)
{
/* create a FIFO buffer */
AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int));
int i, j, n;
/* fill data */
for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++)
av_fifo_generic_write(fifo, &i, sizeof(int), NULL);
/* peek at FIFO */
n = av_fifo_size(fifo)/sizeof(int);
for (i = -n+1; i < n; i++) {
int *v = (int *)av_fifo_peek2(fifo, i*sizeof(int));
printf("%d: %d\n", i, *v);
}
printf("\n");
/* read data */
for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) {
av_fifo_generic_read(fifo, &j, sizeof(int), NULL);
printf("%d ", j);
}
printf("\n");
av_fifo_free(fifo);
return 0;
}
#endif
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