1// <experimental/random> -*- C++ -*- 2 3// Copyright (C) 2015-2022 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 * @ingroup libfund-ts 28 */ 29 30#ifndef _GLIBCXX_EXPERIMENTAL_RANDOM 31#define _GLIBCXX_EXPERIMENTAL_RANDOM 1 32 33#if __cplusplus >= 201402L 34#include <random> 35#include <experimental/bits/lfts_config.h> 36 37namespace std { 38_GLIBCXX_BEGIN_NAMESPACE_VERSION 39 40namespace experimental { 41inline namespace fundamentals_v2 { 42#define __cpp_lib_experimental_randint 201511 43 44 inline std::default_random_engine& 45 _S_randint_engine() 46 { 47 static thread_local default_random_engine __eng{random_device{}()}; 48 return __eng; 49 } 50 51 // 13.2.2.1, Function template randint 52 template<typename _IntType> 53 [[__nodiscard__]] 54 inline _IntType 55 randint(_IntType __a, _IntType __b) 56 { 57 static_assert(is_integral<_IntType>::value && sizeof(_IntType) > 1, 58 "argument must be an integer type"); 59 using _Dist = std::uniform_int_distribution<_IntType>; 60 // This relies on the fact our uniform_int_distribution is stateless, 61 // otherwise we'd need a static thread_local _Dist and pass it 62 // _Dist::param_type{__a, __b}. 63 return _Dist(__a, __b)(_S_randint_engine()); 64 } 65 66 inline void 67 reseed() 68 { 69 _S_randint_engine().seed(random_device{}()); 70 } 71 72 inline void 73 reseed(default_random_engine::result_type __value) 74 { 75 _S_randint_engine().seed(__value); 76 } 77} // namespace fundamentals_v2 78} // namespace experimental 79 80_GLIBCXX_END_NAMESPACE_VERSION 81} // namespace std 82 83#endif // C++14 84#endif // _GLIBCXX_EXPERIMENTAL_RANDOM 85