50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/*
|
|
* Copyright (c) 2011, 2012, 2014 Jonas 'Sortie' Termansen.
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*
|
|
* stdlib/rand.c
|
|
* Returns a random value.
|
|
*/
|
|
|
|
#include <pthread.h>
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
|
|
static pthread_mutex_t rand_mutex = PTHREAD_MUTEX_INITIALIZER;
|
|
static uint32_t m_w = 1337;
|
|
static uint32_t m_z = 37;
|
|
|
|
static uint32_t random_32_bits(void)
|
|
{
|
|
m_z = 36969 * (m_z >> 0 & 0xFFFF) + (m_z >> 16 & 0xFFFF);
|
|
m_w = 18000 * (m_w >> 0 & 0xFFFF) + (m_w >> 16 & 0xFFFF);
|
|
return (m_z << 16) + m_w;
|
|
}
|
|
|
|
int rand(void)
|
|
{
|
|
pthread_mutex_lock(&rand_mutex);
|
|
int result = (int) (random_32_bits() % ((uint32_t) RAND_MAX + 1));
|
|
pthread_mutex_unlock(&rand_mutex);
|
|
return result;
|
|
}
|
|
|
|
void srand(unsigned int seed)
|
|
{
|
|
pthread_mutex_lock(&rand_mutex);
|
|
m_w = seed >> 16 & 0xFFFF;
|
|
m_z = seed >> 0 & 0xFFFF;
|
|
pthread_mutex_unlock(&rand_mutex);
|
|
}
|