yading@11: /*
yading@11:  * a very simple circular buffer FIFO implementation
yading@11:  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
yading@11:  * Copyright (c) 2006 Roman Shaposhnik
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: #include "common.h"
yading@11: #include "fifo.h"
yading@11: 
yading@11: AVFifoBuffer *av_fifo_alloc(unsigned int size)
yading@11: {
yading@11:     AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
yading@11:     if (!f)
yading@11:         return NULL;
yading@11:     f->buffer = av_malloc(size);
yading@11:     f->end = f->buffer + size;
yading@11:     av_fifo_reset(f);
yading@11:     if (!f->buffer)
yading@11:         av_freep(&f);
yading@11:     return f;
yading@11: }
yading@11: 
yading@11: void av_fifo_free(AVFifoBuffer *f)
yading@11: {
yading@11:     if (f) {
yading@11:         av_freep(&f->buffer);
yading@11:         av_free(f);
yading@11:     }
yading@11: }
yading@11: 
yading@11: void av_fifo_reset(AVFifoBuffer *f)
yading@11: {
yading@11:     f->wptr = f->rptr = f->buffer;
yading@11:     f->wndx = f->rndx = 0;
yading@11: }
yading@11: 
yading@11: int av_fifo_size(AVFifoBuffer *f)
yading@11: {
yading@11:     return (uint32_t)(f->wndx - f->rndx);
yading@11: }
yading@11: 
yading@11: int av_fifo_space(AVFifoBuffer *f)
yading@11: {
yading@11:     return f->end - f->buffer - av_fifo_size(f);
yading@11: }
yading@11: 
yading@11: int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size)
yading@11: {
yading@11:     unsigned int old_size = f->end - f->buffer;
yading@11: 
yading@11:     if (old_size < new_size) {
yading@11:         int len = av_fifo_size(f);
yading@11:         AVFifoBuffer *f2 = av_fifo_alloc(new_size);
yading@11: 
yading@11:         if (!f2)
yading@11:             return AVERROR(ENOMEM);
yading@11:         av_fifo_generic_read(f, f2->buffer, len, NULL);
yading@11:         f2->wptr += len;
yading@11:         f2->wndx += len;
yading@11:         av_free(f->buffer);
yading@11:         *f = *f2;
yading@11:         av_free(f2);
yading@11:     }
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: int av_fifo_grow(AVFifoBuffer *f, unsigned int size)
yading@11: {
yading@11:     unsigned int old_size = f->end - f->buffer;
yading@11:     if(size + (unsigned)av_fifo_size(f) < size)
yading@11:         return AVERROR(EINVAL);
yading@11: 
yading@11:     size += av_fifo_size(f);
yading@11: 
yading@11:     if (old_size < size)
yading@11:         return av_fifo_realloc2(f, FFMAX(size, 2*size));
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: // src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
yading@11: int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
yading@11: {
yading@11:     int total = size;
yading@11:     uint32_t wndx= f->wndx;
yading@11:     uint8_t *wptr= f->wptr;
yading@11: 
yading@11:     do {
yading@11:         int len = FFMIN(f->end - wptr, size);
yading@11:         if (func) {
yading@11:             if (func(src, wptr, len) <= 0)
yading@11:                 break;
yading@11:         } else {
yading@11:             memcpy(wptr, src, len);
yading@11:             src = (uint8_t*)src + len;
yading@11:         }
yading@11: // Write memory barrier needed for SMP here in theory
yading@11:         wptr += len;
yading@11:         if (wptr >= f->end)
yading@11:             wptr = f->buffer;
yading@11:         wndx += len;
yading@11:         size -= len;
yading@11:     } while (size > 0);
yading@11:     f->wndx= wndx;
yading@11:     f->wptr= wptr;
yading@11:     return total - size;
yading@11: }
yading@11: 
yading@11: 
yading@11: int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
yading@11: {
yading@11: // Read memory barrier needed for SMP here in theory
yading@11:     do {
yading@11:         int len = FFMIN(f->end - f->rptr, buf_size);
yading@11:         if(func) func(dest, f->rptr, len);
yading@11:         else{
yading@11:             memcpy(dest, f->rptr, len);
yading@11:             dest = (uint8_t*)dest + len;
yading@11:         }
yading@11: // memory barrier needed for SMP here in theory
yading@11:         av_fifo_drain(f, len);
yading@11:         buf_size -= len;
yading@11:     } while (buf_size > 0);
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: /** Discard data from the FIFO. */
yading@11: void av_fifo_drain(AVFifoBuffer *f, int size)
yading@11: {
yading@11:     f->rptr += size;
yading@11:     if (f->rptr >= f->end)
yading@11:         f->rptr -= f->end - f->buffer;
yading@11:     f->rndx += size;
yading@11: }
yading@11: 
yading@11: #ifdef TEST
yading@11: 
yading@11: int main(void)
yading@11: {
yading@11:     /* create a FIFO buffer */
yading@11:     AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int));
yading@11:     int i, j, n;
yading@11: 
yading@11:     /* fill data */
yading@11:     for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++)
yading@11:         av_fifo_generic_write(fifo, &i, sizeof(int), NULL);
yading@11: 
yading@11:     /* peek at FIFO */
yading@11:     n = av_fifo_size(fifo)/sizeof(int);
yading@11:     for (i = -n+1; i < n; i++) {
yading@11:         int *v = (int *)av_fifo_peek2(fifo, i*sizeof(int));
yading@11:         printf("%d: %d\n", i, *v);
yading@11:     }
yading@11:     printf("\n");
yading@11: 
yading@11:     /* read data */
yading@11:     for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) {
yading@11:         av_fifo_generic_read(fifo, &j, sizeof(int), NULL);
yading@11:         printf("%d ", j);
yading@11:     }
yading@11:     printf("\n");
yading@11: 
yading@11:     av_fifo_free(fifo);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: #endif