1 /* $NetBSD: random.cc,v 1.4 2021/12/05 09:22:45 rillig 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 * Randomizer for the dots program
34 */
35
36 #include "defs.h"
37 RCSID("$NetBSD: random.cc,v 1.4 2021/12/05 09:22:45 rillig Exp $")
38
39 #include <time.h>
40 #include <string.h>
41 #include "random.h"
42
RANDOM(size_t ns)43 RANDOM::RANDOM(size_t ns) :
44 _bs(ns)
45 {
46 _bm = new char[(_bs >> 3) + 1];
47 clear();
48 }
49
~RANDOM()50 RANDOM::~RANDOM()
51 {
52 delete[] _bm;
53 }
54
55 // Reinitialize
clear(void)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
operator ()(void)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 }
80