libstdc++
experimental/numeric
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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