55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdlib/rand.c
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Returns a random value.
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*******************************************************************************/
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#include <pthread.h>
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#include <stdint.h>
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#include <stdlib.h>
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static pthread_mutex_t rand_mutex = PTHREAD_MUTEX_INITIALIZER;
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static uint32_t m_w = 1337;
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static uint32_t m_z = 37;
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static uint32_t random_32_bits(void)
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{
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m_z = 36969 * (m_z >> 0 & 0xFFFF) + (m_z >> 16 & 0xFFFF);
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m_w = 18000 * (m_w >> 0 & 0xFFFF) + (m_w >> 16 & 0xFFFF);
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return (m_z << 16) + m_w;
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}
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int rand(void)
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{
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pthread_mutex_lock(&rand_mutex);
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int result = (int) (random_32_bits() % ((uint32_t) RAND_MAX + 1));
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pthread_mutex_unlock(&rand_mutex);
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return result;
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}
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void srand(unsigned int seed)
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{
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pthread_mutex_lock(&rand_mutex);
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m_w = seed >> 16 & 0xFFFF;
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m_z = seed >> 0 & 0xFFFF;
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pthread_mutex_unlock(&rand_mutex);
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}
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