| // <experimental/numeric> -*- C++ -*- |
| |
| // Copyright (C) 2015-2022 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /** @file experimental/numeric |
| * This is a TS C++ Library header. |
| * @ingroup libfund-ts |
| */ |
| |
| // |
| // N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2 |
| // |
| |
| #ifndef _GLIBCXX_EXPERIMENTAL_NUMERIC |
| #define _GLIBCXX_EXPERIMENTAL_NUMERIC 1 |
| |
| #pragma GCC system_header |
| |
| #include <bits/requires_hosted.h> // experimental is currently omitted |
| |
| #if __cplusplus >= 201402L |
| |
| #include <numeric> |
| #include <experimental/type_traits> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| namespace experimental |
| { |
| inline namespace fundamentals_v2 |
| { |
| #define __cpp_lib_experimental_gcd_lcm 201411 |
| |
| /// Greatest common divisor |
| template<typename _Mn, typename _Nn> |
| constexpr common_type_t<_Mn, _Nn> |
| gcd(_Mn __m, _Nn __n) noexcept |
| { |
| static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>, |
| "std::experimental::gcd arguments must be integers"); |
| static_assert(_Mn(2) == 2 && _Nn(2) == 2, |
| "std::experimental::gcd arguments must not be bool"); |
| namespace __detail = std::__detail; |
| using _Ct = common_type_t<_Mn, _Nn>; |
| const _Ct __m2 = __detail::__abs_r<_Ct>(__m); |
| const _Ct __n2 = __detail::__abs_r<_Ct>(__n); |
| return __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2); |
| } |
| |
| /// Least common multiple |
| template<typename _Mn, typename _Nn> |
| constexpr common_type_t<_Mn, _Nn> |
| lcm(_Mn __m, _Nn __n) |
| { |
| static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>, |
| "std::experimental::lcm arguments must be integers"); |
| static_assert(_Mn(2) == 2 && _Nn(2) == 2, |
| "std::experimental::lcm arguments must not be bool"); |
| namespace __detail = std::__detail; |
| using _Ct = common_type_t<_Mn, _Nn>; |
| const _Ct __m2 = __detail::__abs_r<_Ct>(__m); |
| const _Ct __n2 = __detail::__abs_r<_Ct>(__n); |
| if (__m2 == 0 || __n2 == 0) |
| return 0; |
| _Ct __r = __m2 / __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2); |
| |
| if _GLIBCXX17_CONSTEXPR (is_signed_v<_Ct>) |
| if (__is_constant_evaluated()) |
| return __r * __n2; // constant evaluation can detect overflow here. |
| |
| bool __overflow = __builtin_mul_overflow(__r, __n2, &__r); |
| __glibcxx_assert(!__overflow); |
| return __r; |
| } |
| } // namespace fundamentals_v2 |
| } // namespace experimental |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace std |
| |
| #endif // __cplusplus <= 201103L |
| |
| #endif // _GLIBCXX_EXPERIMENTAL_NUMERIC |