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/* $OpenBSD: random.c,v 1.4 2002/07/18 07:13:57 pjanzen Exp $ */
/* $NetBSD: random.c,v 1.3 1995/04/22 10:28:06 cgd Exp $ */
/*
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Timothy C. Stoehr.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)random.c 8.1 (Berkeley) 5/31/93";
#else
static const char rcsid[] = "$OpenBSD: random.c,v 1.4 2002/07/18 07:13:57 pjanzen Exp $";
#endif
#endif /* not lint */
#include "rogue.h"
/*
* random.c
*
* This source herein may be modified and/or distributed by anybody who
* so desires, with the following restrictions:
* 1.) No portion of this notice shall be removed.
* 2.) Credit shall not be taken for the creation of this source.
* 3.) This code is not to be traded, sold, or used for personal
* gain or profit.
*
*/
static long rntb[32] = {
3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342,
0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b,
0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f,
0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d,
0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc,
0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e,
0x8999220b, 0x27fb47b9
};
static long *fptr = &rntb[4];
static long *rptr = &rntb[1];
static long *state = &rntb[1];
static int rand_type = 3;
static int rand_deg = 31;
static int rand_sep = 3;
static long *end_ptr = &rntb[32];
void
srrandom(x)
int x;
{
int i;
state[0] = (long) x;
if (rand_type != 0) {
for (i = 1; i < rand_deg; i++) {
state[i] = 1103515245 * state[i - 1] + 12345;
}
fptr = &state[rand_sep];
rptr = &state[0];
for (i = 0; i < 10 * rand_deg; i++) {
(void) rrandom();
}
}
}
long
rrandom()
{
long i;
if (rand_type == 0) {
i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff;
} else {
*fptr += *rptr;
i = (*fptr >> 1) & 0x7fffffff;
if (++fptr >= end_ptr) {
fptr = state;
++rptr;
} else {
if (++rptr >= end_ptr) {
rptr = state;
}
}
}
return(i);
}
int
get_rand(x, y)
int x, y;
{
int r, t;
long lr;
if (x > y) {
t = y;
y = x;
x = t;
}
lr = rrandom();
lr &= (long) 0x00003fff;
r = (int) lr;
r = (r % ((y - x) + 1)) + x;
return(r);
}
int
rand_percent(percentage)
int percentage;
{
return(get_rand(1, 100) <= percentage);
}
int
coin_toss()
{
return(((rrandom() & 01) ? 1 : 0));
}
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