random.cc revision 1.2 
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 * 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"
44RCSID("$NetBSD: random.cc,v 1.2 2003/12/28 17:49:10 thorpej Exp $")
45
46#include <time.h>
47#include <string.h>
48#include "random.h"
49
50RANDOM::RANDOM(size_t ns) :
51    _bs(ns)
52{
53    _bm = new char[(_bs >> 3) + 1];
54    clear();
55}
56
57RANDOM::~RANDOM()
58{
59    delete[] _bm;
60}
61
62// Reinitialize
63void 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
71size_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}
87