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));
30 f->buffer = av_malloc(size);
31 f->end = f->buffer + size;
38 void av_fifo_free(AVFifoBuffer *f)
46 void av_fifo_reset(AVFifoBuffer *f)
48 f->wptr = f->rptr = f->buffer;
49 f->wndx = f->rndx = 0;
52 int av_fifo_size(AVFifoBuffer *f)
54 return (uint32_t)(f->wndx - f->rndx);
57 int av_fifo_space(AVFifoBuffer *f)
59 return f->end - f->buffer - av_fifo_size(f);
62 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size)
64 unsigned int old_size = f->end - f->buffer;
66 if (old_size < new_size) {
67 int len = av_fifo_size(f);
68 AVFifoBuffer *f2 = av_fifo_alloc(new_size);
71 return AVERROR(ENOMEM);
72 av_fifo_generic_read(f, f2->buffer, len, NULL);
82 // src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
83 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
86 uint32_t wndx= f->wndx;
87 uint8_t *wptr= f->wptr;
90 int len = FFMIN(f->end - wptr, size);
92 if (func(src, wptr, len) <= 0)
95 memcpy(wptr, src, len);
96 src = (uint8_t*)src + len;
98 // Write memory barrier needed for SMP here in theory
111 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
113 // Read memory barrier needed for SMP here in theory
115 int len = FFMIN(f->end - f->rptr, buf_size);
116 if(func) func(dest, f->rptr, len);
118 memcpy(dest, f->rptr, len);
119 dest = (uint8_t*)dest + len;
121 // memory barrier needed for SMP here in theory
122 av_fifo_drain(f, len);
124 } while (buf_size > 0);
128 /** Discard data from the FIFO. */
129 void av_fifo_drain(AVFifoBuffer *f, int size)
132 if (f->rptr >= f->end)
133 f->rptr -= f->end - f->buffer;
143 /* create a FIFO buffer */
144 AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int));
148 for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++)
149 av_fifo_generic_write(fifo, &i, sizeof(int), NULL);
152 n = av_fifo_size(fifo)/sizeof(int);
153 for (i = -n+1; i < n; i++) {
154 int *v = (int *)av_fifo_peek2(fifo, i*sizeof(int));
155 printf("%d: %d\n", i, *v);
160 for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) {
161 av_fifo_generic_read(fifo, &j, sizeof(int), NULL);