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
83