dab/random.C

   1 /*      $Header: /cvsroot/src/games/dab/Attic/random.C,v 1.1.1.1 2003/12/26 17:57:03 christos 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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *        This product includes software developed by the NetBSD
  21  *        Foundation, Inc. and its contributors.
  22  * 4. Neither the name of The NetBSD Foundation nor the names of its
  23  *    contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 /*
  40  * random.C: Randomizer for the dots program
  41  */
  42
  43 #include "defs.h"
  44 RCSID("$Id: random.C,v 1.1.1.1 2003/12/26 17:57:03 christos Exp $")
  45
  46 #include <time.h>
  47 #include <string.h>
  48 #include "random.h"
  49
  50 RANDOM::RANDOM(size_t ns) :
  51     _bs(ns)
  52 {
  53     _bm = new char[(_bs >> 3) + 1];
  54     clear();
  55 }
  56
  57 RANDOM::~RANDOM()
  58 {
  59     delete[] _bm;
  60 }
  61
  62 // Reinitialize
  63 void RANDOM::clear(void)
  64 {
  65     _nv = 0;
  66     ::srand48(::time(NULL));
  67     (void) ::memset(_bm, 0, (_bs >> 3) + 1);
  68 }
  69
  70 // Return the next random value
  71 size_t RANDOM::operator() (void)
  72 {
  73     // No more values
  74     if (_nv == _bs)
  75         return _bs;
  76
  77     for (;;) {
  78         size_t r = ::lrand48();
  79         size_t z = r % _bs;
  80         if (!isset(z)) {
  81             set(z);
  82             _nv++;
  83             return z;
  84         }
  85     }
  86 }