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
44 #if _LIBCPP_STD_VER > 11
46 _LIBCPP_BEGIN_NAMESPACE_LFTS_V2
48 template <typename _Tp, bool _IsSigned = is_signed<_Tp>::value> struct __abs;
50 template <typename _Tp>
51 struct __abs<_Tp, true> {
52 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
53 _Tp operator()(_Tp __t) const noexcept { return __t >= 0 ? __t : -__t; }
56 template <typename _Tp>
57 struct __abs<_Tp, false> {
58 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
59 _Tp operator()(_Tp __t) const noexcept { return __t; }
64 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
65 _Tp __gcd(_Tp __m, _Tp __n)
67 static_assert((!is_signed<_Tp>::value), "" );
68 return __n == 0 ? __m : __gcd<_Tp>(__n, __m % __n);
72 template<class _Tp, class _Up>
73 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
74 common_type_t<_Tp,_Up>
77 static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
78 using _Rp = common_type_t<_Tp,_Up>;
79 using _Wp = make_unsigned_t<_Rp>;
80 return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Tp>()(__m)),
81 static_cast<_Wp>(__abs<_Up>()(__n))));
84 template<class _Tp, class _Up>
85 _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
86 common_type_t<_Tp,_Up>
89 static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
90 if (__m == 0 || __n == 0)
93 using _Rp = common_type_t<_Tp,_Up>;
94 _Rp __val1 = __abs<_Tp>()(__m) / gcd(__m,__n);
95 _Up __val2 = __abs<_Up>()(__n);
96 _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
97 return __val1 * __val2;
100 _LIBCPP_END_NAMESPACE_LFTS_V2
102 #endif /* _LIBCPP_STD_VER > 11 */
103 #endif /* _LIBCPP_EXPERIMENTAL_NUMERIC */