2 * a very simple circular buffer FIFO implementation
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 * Copyright (c) 2006 Roman Shaposhnik
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 AVFifoBuffer *av_fifo_alloc(unsigned int size)
27 AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
31 f->buffer = av_malloc(size);
32 f->end = f->buffer + size;
38 void av_fifo_free(AVFifoBuffer *f)
46 int av_fifo_size(AVFifoBuffer *f)
48 return (uint32_t)(f->wndx - f->rndx);
51 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {
52 unsigned int old_size= f->end - f->buffer;
54 if(old_size < new_size){
55 int len= av_fifo_size(f);
56 AVFifoBuffer *f2= av_fifo_alloc(new_size);
60 av_fifo_generic_read(f, len, NULL, f2->buffer);
70 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
74 int len = FFMIN(f->end - f->wptr, size);
76 if(func(src, f->wptr, len) <= 0)
79 memcpy(f->wptr, src, len);
80 src = (uint8_t*)src + len;
82 // Write memory barrier needed for SMP here in theory
84 if (f->wptr >= f->end)
93 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest)
95 // Read memory barrier needed for SMP here in theory
97 int len = FFMIN(f->end - f->rptr, buf_size);
98 if(func) func(dest, f->rptr, len);
100 memcpy(dest, f->rptr, len);
101 dest = (uint8_t*)dest + len;
103 // memory barrier needed for SMP here in theory
104 av_fifo_drain(f, len);
106 } while (buf_size > 0);
110 /** Discard data from the FIFO. */
111 void av_fifo_drain(AVFifoBuffer *f, int size)
114 if (f->rptr >= f->end)
115 f->rptr -= f->end - f->buffer;