games/dab/random.cc

   1 /*      $NetBSD: random.cc,v 1.2 2003/12/28 17:49:10 thorpej Exp $      */
   2
   3 /*-
   4  * Copyright (c) 2003 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Christos Zoulas.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * random.C: Randomizer for the dots program
  34  */
  35
  36 #include "defs.h"
  37 RCSID("$NetBSD: random.cc,v 1.2 2003/12/28 17:49:10 thorpej Exp $")
  38
  39 #include <time.h>
  40 #include <string.h>
  41 #include "random.h"
  42
  43 RANDOM::RANDOM(size_t ns) :
  44     _bs(ns)
  45 {
  46     _bm = new char[(_bs >> 3) + 1];
  47     clear();
  48 }
  49
  50 RANDOM::~RANDOM()
  51 {
  52     delete[] _bm;
  53 }
  54
  55 // Reinitialize
  56 void RANDOM::clear(void)
  57 {
  58     _nv = 0;
  59     ::srand48(::time(NULL));
  60     (void) ::memset(_bm, 0, (_bs >> 3) + 1);
  61 }
  62
  63 // Return the next random value
  64 size_t RANDOM::operator() (void)
  65 {
  66     // No more values
  67     if (_nv == _bs)
  68         return _bs;
  69
  70     for (;;) {
  71         size_t r = ::lrand48();
  72         size_t z = r % _bs;
  73         if (!isset(z)) {
  74             set(z);
  75             _nv++;
  76             return z;
  77         }
  78     }
  79 }