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. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)random.c 8.1 (Berkeley) 5/31/93
  37  * $FreeBSD: src/games/rogue/random.c,v 1.6 1999/11/30 03:49:26 billf Exp $
  38  * $DragonFly: src/games/rogue/random.c,v 1.3 2006/09/02 19:31:07 pavalos Exp $
  39  */
  40
  41 #include "rogue.h"
  42
  43 /*
  44  * random.c
  45  *
  46  * This source herein may be modified and/or distributed by anybody who
  47  * so desires, with the following restrictions:
  48  *    1.)  No portion of this notice shall be removed.
  49  *    2.)  Credit shall not be taken for the creation of this source.
  50  *    3.)  This code is not to be traded, sold, or used for personal
  51  *         gain or profit.
  52  *
  53  */
  54
  55 int
  56 get_rand(int x, int y)
  57 {
  58         int r, t;
  59         long lr;
  60
  61         if (x > y) {
  62                 t = y;
  63                 y = x;
  64                 x = t;
  65         }
  66         lr = rrandom();
  67         lr &= (long) 0x00003fff;
  68         r = (int) lr;
  69         r = (r % ((y - x) + 1)) + x;
  70         return(r);
  71 }
  72
  73 boolean
  74 rand_percent(int percentage)
  75 {
  76         return(get_rand(1, 100) <= percentage);
  77 }
  78
  79 boolean
  80 coin_toss(void)
  81 {
  82
  83         return(((rrandom() & 01) ? 1 : 0));
  84 }