1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-12 09:58:36 +00:00
freebsd/stand/libsa/random.c
Warner Losh dcaa2d76dc Fix random() and srandom() prototypes to match the standard.
These prototypes were needlessly different from the standard. Fix them
to be the same, and fix the surrounding code after the changes.

Sponsored by: Netflix
2017-12-02 00:07:19 +00:00

71 lines
2.3 KiB
C

/*-
* Copyright (c) 1992, 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.
*
* @(#)random.c 8.1 (Berkeley) 6/10/93
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
static long randseed = 1;
void
srandom(unsigned int seed)
{
randseed = seed;
}
/*
* Pseudo-random number generator for randomizing the profiling clock,
* and whatever else we might use it for. The result is uniform on
* [0, 2^31 - 1].
*/
long
random(void)
{
long x, hi, lo, t;
/*
* Compute x[n + 1] = (7^5 * x[n]) mod (2^31 - 1).
* 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.
*/
x = randseed;
hi = x / 127773;
lo = x % 127773;
t = 16807 * lo - 2836 * hi;
if (t <= 0)
t += 0x7fffffff;
randseed = t;
return (t);
}