| /*- |
| * 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: random.c 1944 2009-04-01 23:12:20Z arcanum $ |
| */ |
| |
| /* |
| * 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; |
| } |
| |