2 * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
4 * This file is part of FFmpeg.
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.
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.
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
25 #include "random_seed.h"
28 static int read_random(uint32_t *dst, const char *file)
30 int fd = open(file, O_RDONLY);
35 err = read(fd, dst, sizeof(*dst));
41 static uint32_t get_generic_seed(void)
47 float s=0.000000000001;
51 if(last_t && fabs(t-last_t)>s || t==(clock_t)-1){
52 if(i<10000 && s<(1<<24)){
56 random= 2*random + (i&1);
63 random ^= AV_READ_TIME();
73 uint32_t av_get_random_seed(void)
77 if (read_random(&seed, "/dev/urandom") == sizeof(seed))
79 if (read_random(&seed, "/dev/random") == sizeof(seed))
81 return get_generic_seed();
84 #if LIBAVUTIL_VERSION_MAJOR < 51
85 attribute_deprecated uint32_t ff_random_get_seed(void);
86 uint32_t ff_random_get_seed(void)
88 return av_get_random_seed();