ffmpeg/libavutil/random_seed.c

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/*
* Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <unistd.h>
#include <fcntl.h>
#include "timer.h"
#include "random_seed.h"
uint32_t ff_random_get_seed(void)
{
uint32_t seed;
int fd;
if ((fd = open("/dev/random", O_RDONLY)) == -1)
fd = open("/dev/urandom", O_RDONLY);
if (fd != -1){
int err = read(fd, &seed, 4);
close(fd);
if (err == 4)
return seed;
}
#ifdef AV_READ_TIME
seed = AV_READ_TIME();
#endif
// XXX what to do ?
return seed;
}