2 //===--------------------------- numeric ----------------------------------===//
4 // The LLVM Compiler Infrastructure
6 // This file is dual licensed under the MIT and the University of Illinois Open
7 // Source Licenses. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 #ifndef _LIBCPP_EXPERIMENTAL_NUMERIC
12 #define _LIBCPP_EXPERIMENTAL_NUMERIC
14 experimental/numeric synopsis
18 namespace experimental {
19 inline namespace fundamentals_v2 {
21 // 13.1.2, Greatest common divisor
22 template<class M, class N>
23 constexpr common_type_t<M,N> gcd(M m, N n);
25 // 13.1.3, Least common multiple
26 template<class M, class N>
27 constexpr common_type_t<M,N> lcm(M m, N n);
29 } // namespace fundamentals_v2
30 } // namespace experimental
35 #include <experimental/__config>
37 #include <type_traits> // is_integral
38 #include <limits> // numeric_limits
40 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
41 #pragma GCC system_header
45 #include <__undef_macros>
47 #if _LIBCPP_STD_VER > 11
49 _LIBCPP_BEGIN_NAMESPACE_LFTS_V2
51 template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __abs;
53 template <typename _Result, typename _Source>
54 struct __abs<_Result, _Source, true> {
55 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
56 _Result operator()(_Source __t) const noexcept
58 if (__t >= 0) return __t;
59 if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
64 template <typename _Result, typename _Source>
65 struct __abs<_Result, _Source, false> {
66 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
67 _Result operator()(_Source __t) const noexcept { return __t; }
72 _LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
73 inline _Tp __gcd(_Tp __m, _Tp __n)
75 static_assert((!is_signed<_Tp>::value), "" );
76 return __n == 0 ? __m : _VSTD_LFTS_V2::__gcd<_Tp>(__n, __m % __n);
80 template<class _Tp, class _Up>
81 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
82 common_type_t<_Tp,_Up>
85 static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
86 static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
87 static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
88 using _Rp = common_type_t<_Tp,_Up>;
89 using _Wp = make_unsigned_t<_Rp>;
90 return static_cast<_Rp>(_VSTD_LFTS_V2::__gcd(
91 static_cast<_Wp>(__abs<_Rp, _Tp>()(__m)),
92 static_cast<_Wp>(__abs<_Rp, _Up>()(__n))));
95 template<class _Tp, class _Up>
96 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
97 common_type_t<_Tp,_Up>
100 static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
101 static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
102 static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
103 if (__m == 0 || __n == 0)
106 using _Rp = common_type_t<_Tp,_Up>;
107 _Rp __val1 = __abs<_Rp, _Tp>()(__m) / _VSTD_LFTS_V2::gcd(__m, __n);
108 _Rp __val2 = __abs<_Rp, _Up>()(__n);
109 _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
110 return __val1 * __val2;
113 _LIBCPP_END_NAMESPACE_LFTS_V2
115 #endif /* _LIBCPP_STD_VER > 11 */
119 #endif /* _LIBCPP_EXPERIMENTAL_NUMERIC */