1 // <experimental/numeric> -*- 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/numeric 26 * This is a TS C++ Library header. 27 * @ingroup libfund-ts 28 */ 29 30 // 31 // N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2 32 // 33 34 #ifndef _GLIBCXX_EXPERIMENTAL_NUMERIC 35 #define _GLIBCXX_EXPERIMENTAL_NUMERIC 1 36 37 #pragma GCC system_header 38 39 #if __cplusplus >= 201402L 40 41 #include <numeric> 42 #include <experimental/type_traits> 43 44 namespace std _GLIBCXX_VISIBILITY(default) 45 { 46 _GLIBCXX_BEGIN_NAMESPACE_VERSION 47 48 namespace experimental 49 { 50 inline namespace fundamentals_v2 51 { 52 #define __cpp_lib_experimental_gcd_lcm 201411 53 54 /// Greatest common divisor 55 template<typename _Mn, typename _Nn> 56 constexpr common_type_t<_Mn, _Nn> 57 gcd(_Mn __m, _Nn __n) noexcept 58 { 59 static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>, 60 "std::experimental::gcd arguments must be integers"); 61 static_assert(_Mn(2) == 2 && _Nn(2) == 2, 62 "std::experimental::gcd arguments must not be bool"); 63 namespace __detail = std::__detail; 64 using _Ct = common_type_t<_Mn, _Nn>; 65 const _Ct __m2 = __detail::__abs_r<_Ct>(__m); 66 const _Ct __n2 = __detail::__abs_r<_Ct>(__n); 67 return __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2); 68 } 69 70 /// Least common multiple 71 template<typename _Mn, typename _Nn> 72 constexpr common_type_t<_Mn, _Nn> 73 lcm(_Mn __m, _Nn __n) 74 { 75 static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>, 76 "std::experimental::lcm arguments must be integers"); 77 static_assert(_Mn(2) == 2 && _Nn(2) == 2, 78 "std::experimental::lcm arguments must not be bool"); 79 namespace __detail = std::__detail; 80 using _Ct = common_type_t<_Mn, _Nn>; 81 const _Ct __m2 = __detail::__abs_r<_Ct>(__m); 82 const _Ct __n2 = __detail::__abs_r<_Ct>(__n); 83 if (__m2 == 0 || __n2 == 0) 84 return 0; 85 _Ct __r = __m2 / __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2); 86 87 if _GLIBCXX17_CONSTEXPR (is_signed_v<_Ct>) 88 if (__is_constant_evaluated()) 89 return __r * __n2; // constant evaluation can detect overflow here. 90 91 bool __overflow = __builtin_mul_overflow(__r, __n2, &__r); 92 __glibcxx_assert(!__overflow); 93 return __r; 94 } 95 } // namespace fundamentals_v2 96 } // namespace experimental 97 98 _GLIBCXX_END_NAMESPACE_VERSION 99 } // namespace std 100 101 #endif // __cplusplus <= 201103L 102 103 #endif // _GLIBCXX_EXPERIMENTAL_NUMERIC 104
Indexes created Sun Mar 01 05:31:48 UTC 2026