add ff_random_get_seed to be used in conjunction with random functions
[libav.git] / libavutil / random_seed.c
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48d58e59
BC
1/*
2 * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <unistd.h>
22#include <fcntl.h>
23#include "timer.h"
24#include "random_seed.h"
25
26uint32_t ff_random_get_seed(void)
27{
28 uint32_t seed;
29 int fd;
30
31 if ((fd = open("/dev/random", O_RDONLY)) == -1)
32 fd = open("/dev/urandom", O_RDONLY);
33 if (fd != -1){
34 read(fd, &seed, 4);
35 close(fd);
36 return seed;
37 }
38#ifdef AV_READ_TIME
39 seed = AV_READ_TIME();
40#endif
41 // XXX what to do ?
42 return seed;
43}