475bd19ee8
This brings most of the enable_ifs in libc++ to the same style. It also has the nice side-effect of reducing the size of names of these symbols, since the depedent return type is shorter. Reviewed By: #libc, ldionne Spies: ldionne, libcxx-commits Differential Revision: https://reviews.llvm.org/D157736
44 lines
1.3 KiB
C++
44 lines
1.3 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___ALGORITHM_HALF_POSITIVE_H
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#define _LIBCPP___ALGORITHM_HALF_POSITIVE_H
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#include <__config>
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#include <__type_traits/enable_if.h>
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#include <__type_traits/is_integral.h>
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#include <__type_traits/make_unsigned.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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// Perform division by two quickly for positive integers (llvm.org/PR39129)
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template <typename _Integral, __enable_if_t<is_integral<_Integral>::value, int> = 0>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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_Integral
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__half_positive(_Integral __value)
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{
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return static_cast<_Integral>(static_cast<__make_unsigned_t<_Integral> >(__value) / 2);
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}
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template <typename _Tp, __enable_if_t<!is_integral<_Tp>::value, int> = 0>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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_Tp
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__half_positive(_Tp __value)
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{
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return __value / 2;
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}
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ALGORITHM_HALF_POSITIVE_H
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