libstdc++
numeric
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00001 // <experimental/numeric> -*- C++ -*-
00002 
00003 // Copyright (C) 2015-2016 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /** @file experimental/numeric
00026  *  This is a TS C++ Library header.
00027  */
00028 
00029 //
00030 // N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
00031 //
00032 
00033 #ifndef _GLIBCXX_EXPERIMENTAL_NUMERIC
00034 #define _GLIBCXX_EXPERIMENTAL_NUMERIC 1
00035 
00036 #pragma GCC system_header
00037 
00038 #if __cplusplus <= 201103L
00039 # include <bits/c++14_warning.h>
00040 #else
00041 
00042 #include <numeric>
00043 #include <experimental/type_traits>
00044 
00045 namespace std _GLIBCXX_VISIBILITY(default)
00046 {
00047 namespace experimental
00048 {
00049 inline namespace fundamentals_v2
00050 {
00051 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00052 
00053 #define __cpp_lib_experimental_gcd_lcm 201411
00054 
00055   // std::abs is not constexpr and doesn't support unsigned integers.
00056   template<typename _Tp>
00057     constexpr
00058     enable_if_t<__and_<is_integral<_Tp>, is_signed<_Tp>>::value, _Tp>
00059     __abs(_Tp __val)
00060     { return __val < 0 ? -__val : __val; }
00061 
00062   template<typename _Tp>
00063     constexpr
00064     enable_if_t<__and_<is_integral<_Tp>, is_unsigned<_Tp>>::value, _Tp>
00065     __abs(_Tp __val)
00066     { return __val; }
00067 
00068   // Greatest common divisor
00069   template<typename _Mn, typename _Nn>
00070     constexpr common_type_t<_Mn, _Nn>
00071     gcd(_Mn __m, _Nn __n)
00072     {
00073       static_assert(is_integral<_Mn>::value, "arguments to gcd are integers");
00074       static_assert(is_integral<_Nn>::value, "arguments to gcd are integers");
00075 
00076       return __m == 0 ? fundamentals_v2::__abs(__n)
00077         : __n == 0 ? fundamentals_v2::__abs(__m)
00078         : fundamentals_v2::gcd(__n, __m % __n);
00079     }
00080 
00081   // Least common multiple
00082   template<typename _Mn, typename _Nn>
00083     constexpr common_type_t<_Mn, _Nn>
00084     lcm(_Mn __m, _Nn __n)
00085     {
00086       static_assert(is_integral<_Mn>::value, "arguments to lcm are integers");
00087       static_assert(is_integral<_Nn>::value, "arguments to lcm are integers");
00088 
00089       return (__m != 0 && __n != 0)
00090         ? (fundamentals_v2::__abs(__m) / fundamentals_v2::gcd(__m, __n))
00091           * fundamentals_v2::__abs(__n)
00092         : 0;
00093     }
00094 
00095 _GLIBCXX_END_NAMESPACE_VERSION
00096 } // namespace fundamentals_v2
00097 } // namespace experimental
00098 } // namespace std
00099 
00100 #endif // __cplusplus <= 201103L
00101 
00102 #endif // _GLIBCXX_EXPERIMENTAL_NUMERIC