libstdc++
experimental/random
Go to the documentation of this file.
1// <experimental/random> -*- C++ -*-
2
3// Copyright (C) 2015-2019 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file experimental/random
26 * This is a TS C++ Library header.
27 */
28
29#ifndef _GLIBCXX_EXPERIMENTAL_RANDOM
30#define _GLIBCXX_EXPERIMENTAL_RANDOM 1
31
32#if __cplusplus >= 201402L
33#include <random>
34#include <experimental/bits/lfts_config.h>
35
36namespace std {
37_GLIBCXX_BEGIN_NAMESPACE_VERSION
38
39namespace experimental {
40inline namespace fundamentals_v2 {
41#define __cpp_lib_experimental_randint 201511
42
43 inline std::default_random_engine&
44 _S_randint_engine()
45 {
46 static thread_local default_random_engine __eng{random_device{}()};
47 return __eng;
48 }
49
50 // 13.2.2.1, Function template randint
51 template<typename _IntType>
52 inline _IntType
53 randint(_IntType __a, _IntType __b)
54 {
55 static_assert(is_integral<_IntType>::value && sizeof(_IntType) > 1,
56 "argument must be an integer type");
57 using _Dist = std::uniform_int_distribution<_IntType>;
58 // This relies on the fact our uniform_int_distribution is stateless,
59 // otherwise we'd need a static thread_local _Dist and pass it
60 // _Dist::param_type{__a, __b}.
61 return _Dist(__a, __b)(_S_randint_engine());
62 }
63
64 inline void
65 reseed()
66 {
67 _S_randint_engine().seed(random_device{}());
68 }
69
70 inline void
71 reseed(default_random_engine::result_type __value)
72 {
73 _S_randint_engine().seed(__value);
74 }
75} // namespace fundamentals_v2
76} // namespace experimental
77
78_GLIBCXX_END_NAMESPACE_VERSION
79} // namespace std
80
81#endif // C++14
82#endif // _GLIBCXX_EXPERIMENTAL_RANDOM