104 lines
3.3 KiB
Text
104 lines
3.3 KiB
Text
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// <experimental/numeric> -*- C++ -*-
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// Copyright (C) 2015-2022 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/numeric
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* This is a TS C++ Library header.
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* @ingroup libfund-ts
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*/
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//
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// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
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//
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#ifndef _GLIBCXX_EXPERIMENTAL_NUMERIC
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#define _GLIBCXX_EXPERIMENTAL_NUMERIC 1
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#pragma GCC system_header
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#if __cplusplus >= 201402L
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#include <numeric>
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#include <experimental/type_traits>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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namespace experimental
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{
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inline namespace fundamentals_v2
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{
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#define __cpp_lib_experimental_gcd_lcm 201411
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/// Greatest common divisor
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template<typename _Mn, typename _Nn>
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constexpr common_type_t<_Mn, _Nn>
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gcd(_Mn __m, _Nn __n) noexcept
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{
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static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
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"std::experimental::gcd arguments must be integers");
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static_assert(_Mn(2) == 2 && _Nn(2) == 2,
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"std::experimental::gcd arguments must not be bool");
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namespace __detail = std::__detail;
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using _Ct = common_type_t<_Mn, _Nn>;
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const _Ct __m2 = __detail::__abs_r<_Ct>(__m);
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const _Ct __n2 = __detail::__abs_r<_Ct>(__n);
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return __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
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}
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/// Least common multiple
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template<typename _Mn, typename _Nn>
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constexpr common_type_t<_Mn, _Nn>
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lcm(_Mn __m, _Nn __n)
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{
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static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
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"std::experimental::lcm arguments must be integers");
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static_assert(_Mn(2) == 2 && _Nn(2) == 2,
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"std::experimental::lcm arguments must not be bool");
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namespace __detail = std::__detail;
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using _Ct = common_type_t<_Mn, _Nn>;
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const _Ct __m2 = __detail::__abs_r<_Ct>(__m);
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const _Ct __n2 = __detail::__abs_r<_Ct>(__n);
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if (__m2 == 0 || __n2 == 0)
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return 0;
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_Ct __r = __m2 / __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
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if _GLIBCXX17_CONSTEXPR (is_signed_v<_Ct>)
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if (__is_constant_evaluated())
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return __r * __n2; // constant evaluation can detect overflow here.
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bool __overflow = __builtin_mul_overflow(__r, __n2, &__r);
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__glibcxx_assert(!__overflow);
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return __r;
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}
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} // namespace fundamentals_v2
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} // namespace experimental
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif // __cplusplus <= 201103L
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#endif // _GLIBCXX_EXPERIMENTAL_NUMERIC
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