blob: 4156b3bb1e3993b46d43d5a497e5270a8f41e4b9 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/*
* Copyright (C) 2003-2014 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_LAZY_RANDOM_ENGINE_HXX
#define MPD_LAZY_RANDOM_ENGINE_HXX
#include "check.h"
#include <random>
#include <assert.h>
/**
* A random engine that will be created and seeded on demand.
*/
class LazyRandomEngine {
std::mt19937 *engine;
public:
typedef std::mt19937::result_type result_type;
LazyRandomEngine():engine(nullptr) {}
~LazyRandomEngine() {
delete engine;
}
LazyRandomEngine(const LazyRandomEngine &other) = delete;
LazyRandomEngine &operator=(const LazyRandomEngine &other) = delete;
/**
* Create and seed the real engine. Call this before any
* other method.
*/
void AutoCreate();
static constexpr result_type min() {
return std::mt19937::min();
}
static constexpr result_type max() {
return std::mt19937::max();
}
result_type operator()() {
assert(engine != nullptr);
return engine->operator()();
}
};
#endif
|
