1// <experimental/numeric> -*- C++ -*- 2 3// Copyright (C) 2015-2016 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 */ 28 29// 30// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2 31// 32 33#ifndef _GLIBCXX_EXPERIMENTAL_NUMERIC 34#define _GLIBCXX_EXPERIMENTAL_NUMERIC 1 35 36#pragma GCC system_header 37 38#if __cplusplus <= 201103L 39# include <bits/c++14_warning.h> 40#else 41 42#include <numeric> 43#include <experimental/type_traits> 44 45namespace std _GLIBCXX_VISIBILITY(default) 46{ 47namespace experimental 48{ 49inline namespace fundamentals_v2 50{ 51_GLIBCXX_BEGIN_NAMESPACE_VERSION 52 53#define __cpp_lib_experimental_gcd_lcm 201411 54 55 // std::abs is not constexpr and doesn't support unsigned integers. 56 template<typename _Tp> 57 constexpr 58 enable_if_t<__and_<is_integral<_Tp>, is_signed<_Tp>>::value, _Tp> 59 __abs(_Tp __val) 60 { return __val < 0 ? -__val : __val; } 61 62 template<typename _Tp> 63 constexpr 64 enable_if_t<__and_<is_integral<_Tp>, is_unsigned<_Tp>>::value, _Tp> 65 __abs(_Tp __val) 66 { return __val; } 67 68 // Greatest common divisor 69 template<typename _Mn, typename _Nn> 70 constexpr common_type_t<_Mn, _Nn> 71 gcd(_Mn __m, _Nn __n) 72 { 73 static_assert(is_integral<_Mn>::value, "arguments to gcd are integers"); 74 static_assert(is_integral<_Nn>::value, "arguments to gcd are integers"); 75 76 return __m == 0 ? fundamentals_v2::__abs(__n) 77 : __n == 0 ? fundamentals_v2::__abs(__m) 78 : fundamentals_v2::gcd(__n, __m % __n); 79 } 80 81 // Least common multiple 82 template<typename _Mn, typename _Nn> 83 constexpr common_type_t<_Mn, _Nn> 84 lcm(_Mn __m, _Nn __n) 85 { 86 static_assert(is_integral<_Mn>::value, "arguments to lcm are integers"); 87 static_assert(is_integral<_Nn>::value, "arguments to lcm are integers"); 88 89 return (__m != 0 && __n != 0) 90 ? (fundamentals_v2::__abs(__m) / fundamentals_v2::gcd(__m, __n)) 91 * fundamentals_v2::__abs(__n) 92 : 0; 93 } 94 95_GLIBCXX_END_NAMESPACE_VERSION 96} // namespace fundamentals_v2 97} // namespace experimental 98} // namespace std 99 100#endif // __cplusplus <= 201103L 101 102#endif // _GLIBCXX_EXPERIMENTAL_NUMERIC 103