| //===----------------------------------------------------------------------===// |
| // |
| // 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___ALGORITHM_HALF_POSITIVE_H |
| #define _LIBCPP___ALGORITHM_HALF_POSITIVE_H |
| |
| #include <__config> |
| #include <__type_traits/enable_if.h> |
| #include <__type_traits/is_integral.h> |
| #include <__type_traits/make_unsigned.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| // Perform division by two quickly for positive integers (llvm.org/PR39129) |
| |
| template <typename _Integral, __enable_if_t<is_integral<_Integral>::value, int> = 0> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Integral __half_positive(_Integral __value) { |
| return static_cast<_Integral>(static_cast<__make_unsigned_t<_Integral> >(__value) / 2); |
| } |
| |
| template <typename _Tp, __enable_if_t<!is_integral<_Tp>::value, int> = 0> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp __half_positive(_Tp __value) { |
| return __value / 2; |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___ALGORITHM_HALF_POSITIVE_H |
