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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___NUMERIC_GCD_LCM_H
#define _LIBCPP___NUMERIC_GCD_LCM_H
#include <__assert>
#include <__config>
#include <__type_traits/common_type.h>
#include <__type_traits/is_integral.h>
#include <__type_traits/is_same.h>
#include <__type_traits/is_signed.h>
#include <__type_traits/make_unsigned.h>
#include <limits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 17
template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __ct_abs;
template <typename _Result, typename _Source>
struct __ct_abs<_Result, _Source, true> {
_LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
_Result operator()(_Source __t) const noexcept
{
if (__t >= 0) return __t;
if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
return -__t;
}
};
template <typename _Result, typename _Source>
struct __ct_abs<_Result, _Source, false> {
_LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
_Result operator()(_Source __t) const noexcept { return __t; }
};
template<class _Tp>
_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
_Tp __gcd(_Tp __m, _Tp __n)
{
static_assert((!is_signed<_Tp>::value), "");
return __n == 0 ? __m : std::__gcd<_Tp>(__n, __m % __n);
}
template<class _Tp, class _Up>
_LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
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");
static_assert((!is_same<__remove_cv_t<_Tp>, bool>::value), "First argument to gcd cannot be bool" );
static_assert((!is_same<__remove_cv_t<_Up>, bool>::value), "Second argument to gcd cannot be bool" );
using _Rp = common_type_t<_Tp,_Up>;
using _Wp = make_unsigned_t<_Rp>;
return static_cast<_Rp>(std::__gcd(
static_cast<_Wp>(__ct_abs<_Rp, _Tp>()(__m)),
static_cast<_Wp>(__ct_abs<_Rp, _Up>()(__n))));
}
template<class _Tp, class _Up>
_LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
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");
static_assert((!is_same<__remove_cv_t<_Tp>, bool>::value), "First argument to lcm cannot be bool" );
static_assert((!is_same<__remove_cv_t<_Up>, bool>::value), "Second argument to lcm cannot be bool" );
if (__m == 0 || __n == 0)
return 0;
using _Rp = common_type_t<_Tp,_Up>;
_Rp __val1 = __ct_abs<_Rp, _Tp>()(__m) / std::gcd(__m, __n);
_Rp __val2 = __ct_abs<_Rp, _Up>()(__n);
_LIBCPP_ASSERT_UNCATEGORIZED((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
return __val1 * __val2;
}
#endif // _LIBCPP_STD_VER
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___NUMERIC_GCD_LCM_H
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