games/rogue/random.c

   1 /*-
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Timothy C. Stoehr.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * @(#)random.c 8.1 (Berkeley) 5/31/93
  33  * $FreeBSD: src/games/rogue/random.c,v 1.6 1999/11/30 03:49:26 billf Exp $
  34  */
  35
  36 #include "rogue.h"
  37
  38 /*
  39  * random.c
  40  *
  41  * This source herein may be modified and/or distributed by anybody who
  42  * so desires, with the following restrictions:
  43  *    1.)  No portion of this notice shall be removed.
  44  *    2.)  Credit shall not be taken for the creation of this source.
  45  *    3.)  This code is not to be traded, sold, or used for personal
  46  *         gain or profit.
  47  *
  48  */
  49
  50 int
  51 get_rand(int x, int y)
  52 {
  53         int r, t;
  54         long lr;
  55
  56         if (x > y) {
  57                 t = y;
  58                 y = x;
  59                 x = t;
  60         }
  61         lr = rrandom();
  62         lr &= 0x00003fffL;
  63         r = (int)lr;
  64         r = (r % ((y - x) + 1)) + x;
  65         return(r);
  66 }
  67
  68 boolean
  69 rand_percent(int percentage)
  70 {
  71         return(get_rand(1, 100) <= percentage);
  72 }
  73
  74 boolean
  75 coin_toss(void)
  76 {
  77         return(((rrandom() & 01) ? 1 : 0));
  78 }