libstdc++
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00001 // <experimental/random> -*- C++ -*- 00002 00003 // Copyright (C) 2015-2018 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file experimental/random 00026 * This is a TS C++ Library header. 00027 */ 00028 00029 #ifndef _GLIBCXX_EXPERIMENTAL_RANDOM 00030 #define _GLIBCXX_EXPERIMENTAL_RANDOM 1 00031 00032 #include <random> 00033 #include <experimental/bits/lfts_config.h> 00034 00035 namespace std { 00036 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00037 00038 namespace experimental { 00039 inline namespace fundamentals_v2 { 00040 #define __cpp_lib_experimental_randint 201511 00041 00042 inline std::default_random_engine& 00043 _S_randint_engine() 00044 { 00045 static thread_local default_random_engine __eng{random_device{}()}; 00046 return __eng; 00047 } 00048 00049 // 13.2.2.1, Function template randint 00050 template<typename _IntType> 00051 inline _IntType 00052 randint(_IntType __a, _IntType __b) 00053 { 00054 static_assert(is_integral<_IntType>::value && sizeof(_IntType) > 1, 00055 "argument must be an integer type"); 00056 using _Dist = std::uniform_int_distribution<_IntType>; 00057 // This relies on the fact our uniform_int_distribution is stateless, 00058 // otherwise we'd need a static thread_local _Dist and pass it 00059 // _Dist::param_type{__a, __b}. 00060 return _Dist(__a, __b)(_S_randint_engine()); 00061 } 00062 00063 inline void 00064 reseed() 00065 { 00066 _S_randint_engine().seed(random_device{}()); 00067 } 00068 00069 inline void 00070 reseed(default_random_engine::result_type __value) 00071 { 00072 _S_randint_engine().seed(__value); 00073 } 00074 } // namespace fundamentals_v2 00075 } // namespace experimental 00076 00077 _GLIBCXX_END_NAMESPACE_VERSION 00078 } // namespace std 00079 00080 #endif