147 lines
3.8 KiB
C
147 lines
3.8 KiB
C
/* $NetBSD: random.c,v 1.8 2009/08/12 08:44:45 dholland Exp $ */
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/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Timothy C. Stoehr.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)random.c 8.1 (Berkeley) 5/31/93";
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#else
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__RCSID("$NetBSD: random.c,v 1.8 2009/08/12 08:44:45 dholland Exp $");
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#endif
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#endif /* not lint */
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#include "rogue.h"
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/*
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* random.c
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*
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* This source herein may be modified and/or distributed by anybody who
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* so desires, with the following restrictions:
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* 1.) No portion of this notice shall be removed.
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* 2.) Credit shall not be taken for the creation of this source.
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* 3.) This code is not to be traded, sold, or used for personal
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* gain or profit.
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*
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*/
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static long rntb[32] = {
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3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342,
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0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b,
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0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f,
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0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d,
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0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc,
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0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e,
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0x8999220b, 0x27fb47b9
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};
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static long *fptr = &rntb[4];
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static long *rptr = &rntb[1];
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static long *state = &rntb[1];
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static int rand_type = 3;
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static int rand_deg = 31;
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static int rand_sep = 3;
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static long *end_ptr = &rntb[32];
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static long rrandom(void);
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void
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srrandom(int x)
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{
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int i;
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state[0] = x;
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if (rand_type != 0) {
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for (i = 1; i < rand_deg; i++) {
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state[i] = 1103515245 * state[i - 1] + 12345;
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}
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fptr = &state[rand_sep];
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rptr = &state[0];
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for (i = 0; i < 10 * rand_deg; i++) {
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(void)rrandom();
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}
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}
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}
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static long
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rrandom(void)
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{
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long i;
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if (rand_type == 0) {
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i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff;
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} else {
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*fptr += *rptr;
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i = (*fptr >> 1) & 0x7fffffff;
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if (++fptr >= end_ptr) {
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fptr = state;
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++rptr;
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} else {
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if (++rptr >= end_ptr) {
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rptr = state;
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}
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}
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}
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return(i);
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}
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int
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get_rand(int x, int y)
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{
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int r, t;
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long lr;
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if (x > y) {
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t = y;
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y = x;
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x = t;
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}
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lr = rrandom();
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lr &= 0x00003fffL;
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r = (int)lr;
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r = (r % ((y - x) + 1)) + x;
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return(r);
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}
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int
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rand_percent(int percentage)
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{
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return(get_rand(1, 100) <= percentage);
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}
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int
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coin_toss(void)
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{
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return(((rrandom() & 01) ? 1 : 0));
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}
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