experimental/numeric
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// <experimental/numeric> -*- C++ -*-
// Copyright (C) 2015-2023 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file experimental/numeric
* This is a TS C++ Library header.
* @ingroup libfund-ts
*/
//
// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
//
#ifndef _GLIBCXX_EXPERIMENTAL_NUMERIC
#define _GLIBCXX_EXPERIMENTAL_NUMERIC 1
#pragma GCC system_header
#include <bits/requires_hosted.h> // experimental is currently omitted
#if __cplusplus >= 201402L
#include <numeric>
#include <experimental/type_traits>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace experimental
{
inline namespace fundamentals_v2
{
#define __cpp_lib_experimental_gcd_lcm 201411
/// Greatest common divisor
template<typename _Mn, typename _Nn>
constexpr common_type_t<_Mn, _Nn>
gcd(_Mn __m, _Nn __n) noexcept
{
static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
"std::experimental::gcd arguments must be integers");
static_assert(_Mn(2) == 2 && _Nn(2) == 2,
"std::experimental::gcd arguments must not be bool");
namespace __detail = std::__detail;
using _Ct = common_type_t<_Mn, _Nn>;
const _Ct __m2 = __detail::__abs_r<_Ct>(__m);
const _Ct __n2 = __detail::__abs_r<_Ct>(__n);
return __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
}
/// Least common multiple
template<typename _Mn, typename _Nn>
constexpr common_type_t<_Mn, _Nn>
lcm(_Mn __m, _Nn __n)
{
static_assert(is_integral_v<_Mn> && is_integral_v<_Nn>,
"std::experimental::lcm arguments must be integers");
static_assert(_Mn(2) == 2 && _Nn(2) == 2,
"std::experimental::lcm arguments must not be bool");
namespace __detail = std::__detail;
using _Ct = common_type_t<_Mn, _Nn>;
const _Ct __m2 = __detail::__abs_r<_Ct>(__m);
const _Ct __n2 = __detail::__abs_r<_Ct>(__n);
if (__m2 == 0 || __n2 == 0)
return 0;
_Ct __r = __m2 / __detail::__gcd<make_unsigned_t<_Ct>>(__m2, __n2);
if _GLIBCXX17_CONSTEXPR (is_signed_v<_Ct>)
if (__is_constant_evaluated())
return __r * __n2; // constant evaluation can detect overflow here.
bool __overflow = __builtin_mul_overflow(__r, __n2, &__r);
__glibcxx_assert(!__overflow);
return __r;
}
} // namespace fundamentals_v2
} // namespace experimental
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __cplusplus <= 201103L
#endif // _GLIBCXX_EXPERIMENTAL_NUMERIC