ad2fbea797
This has the benefit of consistent placement for these macros (outside the namespace, not inside it). This, in turn, makes it more obvious that the condition applies to the entire namespace scope. Compile times are also reduced a bit, since the compiler doesn't have to open a namespace just to close it again. This is enforced with a clang-tidy check. As a drive-by this also fixes a few macro comments.
55 lines
1.6 KiB
C++
55 lines
1.6 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___BIT_BIT_CEIL_H
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#define _LIBCPP___BIT_BIT_CEIL_H
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#include <__assert>
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#include <__bit/countl.h>
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#include <__config>
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#include <__type_traits/integer_traits.h>
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#include <limits>
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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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#if _LIBCPP_STD_VER >= 17
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Tp>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp __bit_ceil(_Tp __t) noexcept {
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if (__t < 2)
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return 1;
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const unsigned __n = numeric_limits<_Tp>::digits - std::__countl_zero((_Tp)(__t - 1u));
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_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(__n != numeric_limits<_Tp>::digits, "Bad input to bit_ceil");
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if constexpr (sizeof(_Tp) >= sizeof(unsigned))
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return _Tp{1} << __n;
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else {
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const unsigned __extra = numeric_limits<unsigned>::digits - numeric_limits<_Tp>::digits;
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const unsigned __ret_val = 1u << (__n + __extra);
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return (_Tp)(__ret_val >> __extra);
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}
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}
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# if _LIBCPP_STD_VER >= 20
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template <__unsigned_integer _Tp>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_ceil(_Tp __t) noexcept {
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return std::__bit_ceil(__t);
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}
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# endif // _LIBCPP_STD_VER >= 20
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 17
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#endif // _LIBCPP___BIT_BIT_CEIL_H
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