b08fdbb845
PR libstdc++/68925 * include/experimental/random (randint): Use temporary instead of thread_local static. From-SVN: r244584
81 lines
2.4 KiB
C++
81 lines
2.4 KiB
C++
// <experimental/random> -*- C++ -*-
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// Copyright (C) 2015-2017 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file experimental/random
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* This is a TS C++ Library header.
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*/
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#ifndef _GLIBCXX_EXPERIMENTAL_RANDOM
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#define _GLIBCXX_EXPERIMENTAL_RANDOM 1
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#include <random>
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#include <experimental/bits/lfts_config.h>
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namespace std {
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namespace experimental {
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inline namespace fundamentals_v2 {
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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#define __cpp_lib_experimental_randint 201511
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inline std::default_random_engine&
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_S_randint_engine()
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{
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static thread_local default_random_engine __eng{random_device{}()};
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return __eng;
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}
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// 13.2.2.1, Function template randint
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template<typename _IntType>
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inline _IntType
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randint(_IntType __a, _IntType __b)
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{
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static_assert(is_integral<_IntType>::value && sizeof(_IntType) > 1,
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"argument must be an integer type");
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using _Dist = std::uniform_int_distribution<_IntType>;
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// This relies on the fact our uniform_int_distribution is stateless,
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// otherwise we'd need a static thread_local _Dist and pass it
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// _Dist::param_type{__a, __b}.
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return _Dist(__a, __b)(_S_randint_engine());
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}
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inline void
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reseed()
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{
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_S_randint_engine().seed(random_device{}());
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}
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inline void
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reseed(default_random_engine::result_type __value)
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{
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_S_randint_engine().seed(__value);
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace fundamentals_v2
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} // namespace experimental
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} // namespace std
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#endif
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