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/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Posix rand_r function added May 1999 by Wes Peters <wes@softweyr.com>.
*
* $Id: rand.c,v 1.3.2.1 2009/04/01 23:12:11 arcanum Exp $
*/
/*
* From:
static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93";
*/
#include <stdlib.h>
#include "sectionname.h"
ATTRIBUTE_CLIB_SECTION
static int
do_rand(unsigned long *ctx)
{
#ifdef USE_WEAK_SEEDING
/*
* Historic implementation compatibility.
* The random sequences do not vary much with the seed,
* even with overflowing.
*/
return ((*ctx = *ctx * 1103515245L + 12345L) %
((unsigned long)RAND_MAX + 1));
#else /* !USE_WEAK_SEEDING */
/*
* Compute x = (7^5 * x) mod (2^31 - 1)
* wihout overflowing 31 bits:
* (2^31 - 1) = 127773 * (7^5) + 2836
* From "Random number generators: good ones are hard to find",
* Park and Miller, Communications of the ACM, vol. 31, no. 10,
* October 1988, p. 1195.
*/
long hi, lo, x;
x = *ctx;
/* Can't be initialized with 0, so use another value. */
if (x == 0)
x = 123459876L;
hi = x / 127773L;
lo = x % 127773L;
x = 16807L * lo - 2836L * hi;
if (x < 0)
x += 0x7fffffffL;
return ((*ctx = x) % ((unsigned long)RAND_MAX + 1));
#endif /* !USE_WEAK_SEEDING */
}
ATTRIBUTE_CLIB_SECTION
int
rand_r(unsigned long *ctx)
{
return do_rand(ctx);
}
static unsigned long next = 1;
ATTRIBUTE_CLIB_SECTION
int
rand(void)
{
return do_rand(&next);
}
ATTRIBUTE_CLIB_SECTION
void
srand(unsigned int seed)
{
next = seed;
}
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