/*- * 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>. * * $Id$ */ /* * From: static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93"; */ #include <stdlib.h> #include "sectionname.h" ATTRIBUTE_CLIB_SECTION static long do_random(unsigned long *ctx) { /* * 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)RANDOM_MAX + 1)); } ATTRIBUTE_CLIB_SECTION long random_r(unsigned long *ctx) { return do_random(ctx); } static unsigned long next = 1; ATTRIBUTE_CLIB_SECTION long random(void) { return do_random(&next); } ATTRIBUTE_CLIB_SECTION void srandom(unsigned long seed) { next = seed; }