xref: /llvm-project/libcxx/include/__bit/bit_width.h (revision 83bc7b57714dc2f6b33c188f2b95a0025468ba51)
186aac87fSNikolas Klauser //===----------------------------------------------------------------------===//
286aac87fSNikolas Klauser //
386aac87fSNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
486aac87fSNikolas Klauser // See https://llvm.org/LICENSE.txt for license information.
586aac87fSNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
686aac87fSNikolas Klauser //
786aac87fSNikolas Klauser //===----------------------------------------------------------------------===//
886aac87fSNikolas Klauser 
986aac87fSNikolas Klauser #ifndef _LIBCPP___BIT_BIT_WIDTH_H
1086aac87fSNikolas Klauser #define _LIBCPP___BIT_BIT_WIDTH_H
1186aac87fSNikolas Klauser 
1286aac87fSNikolas Klauser #include <__bit/bit_log2.h>
1386aac87fSNikolas Klauser #include <__concepts/arithmetic.h>
1486aac87fSNikolas Klauser #include <__config>
1586aac87fSNikolas Klauser 
1686aac87fSNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
1786aac87fSNikolas Klauser #  pragma GCC system_header
1886aac87fSNikolas Klauser #endif
1986aac87fSNikolas Klauser 
2086aac87fSNikolas Klauser #if _LIBCPP_STD_VER >= 20
2186aac87fSNikolas Klauser 
2286aac87fSNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD
2386aac87fSNikolas Klauser 
2486aac87fSNikolas Klauser template <__libcpp_unsigned_integer _Tp>
bit_width(_Tp __t)25*83bc7b57SNikolas Klauser [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
2686aac87fSNikolas Klauser   return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
2786aac87fSNikolas Klauser }
2886aac87fSNikolas Klauser 
2986aac87fSNikolas Klauser _LIBCPP_END_NAMESPACE_STD
3086aac87fSNikolas Klauser 
3186aac87fSNikolas Klauser #endif // _LIBCPP_STD_VER >= 20
3286aac87fSNikolas Klauser 
3386aac87fSNikolas Klauser #endif // _LIBCPP___BIT_BIT_WIDTH_H
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