forked from OSchip/llvm-project
104 lines
2.8 KiB
C++
104 lines
2.8 KiB
C++
// -*- C++ -*-
|
|
//===--------------------------- numeric ----------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _LIBCPP_EXPERIMENTAL_NUMERIC
|
|
#define _LIBCPP_EXPERIMENTAL_NUMERIC
|
|
/*
|
|
experimental/numeric synopsis
|
|
|
|
// C++1z
|
|
namespace std {
|
|
namespace experimental {
|
|
inline namespace fundamentals_v2 {
|
|
|
|
// 13.1.2, Greatest common divisor
|
|
template<class M, class N>
|
|
constexpr common_type_t<M,N> gcd(M m, N n);
|
|
|
|
// 13.1.3, Least common multiple
|
|
template<class M, class N>
|
|
constexpr common_type_t<M,N> lcm(M m, N n);
|
|
|
|
} // namespace fundamentals_v2
|
|
} // namespace experimental
|
|
} // namespace std
|
|
|
|
*/
|
|
|
|
#include <experimental/__config>
|
|
#include <numeric>
|
|
#include <type_traits> // is_integral
|
|
#include <limits> // numeric_limits
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
#pragma GCC system_header
|
|
#endif
|
|
|
|
#if _LIBCPP_STD_VER > 11
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_LFTS_V2
|
|
|
|
template <typename _Tp, bool _IsSigned = is_signed<_Tp>::value> struct __abs;
|
|
|
|
template <typename _Tp>
|
|
struct __abs<_Tp, true> {
|
|
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
|
|
_Tp operator()(_Tp __t) const noexcept { return __t >= 0 ? __t : -__t; }
|
|
};
|
|
|
|
template <typename _Tp>
|
|
struct __abs<_Tp, false> {
|
|
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
|
|
_Tp operator()(_Tp __t) const noexcept { return __t; }
|
|
};
|
|
|
|
|
|
template<class _Tp>
|
|
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
|
|
_Tp __gcd(_Tp __m, _Tp __n)
|
|
{
|
|
static_assert((!is_signed<_Tp>::value), "" );
|
|
return __n == 0 ? __m : __gcd<_Tp>(__n, __m % __n);
|
|
}
|
|
|
|
|
|
template<class _Tp, class _Up>
|
|
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
|
|
common_type_t<_Tp,_Up>
|
|
gcd(_Tp __m, _Up __n)
|
|
{
|
|
static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
|
|
using _Rp = common_type_t<_Tp,_Up>;
|
|
using _Wp = make_unsigned_t<_Rp>;
|
|
return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Tp>()(__m)),
|
|
static_cast<_Wp>(__abs<_Up>()(__n))));
|
|
}
|
|
|
|
template<class _Tp, class _Up>
|
|
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
|
|
common_type_t<_Tp,_Up>
|
|
lcm(_Tp __m, _Up __n)
|
|
{
|
|
static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
|
|
if (__m == 0 || __n == 0)
|
|
return 0;
|
|
|
|
using _Rp = common_type_t<_Tp,_Up>;
|
|
_Rp __val1 = __abs<_Tp>()(__m) / gcd(__m,__n);
|
|
_Up __val2 = __abs<_Up>()(__n);
|
|
_LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
|
|
return __val1 * __val2;
|
|
}
|
|
|
|
_LIBCPP_END_NAMESPACE_LFTS_V2
|
|
|
|
#endif /* _LIBCPP_STD_VER > 11 */
|
|
#endif /* _LIBCPP_EXPERIMENTAL_NUMERIC */
|