xref: /llvm-project/libcxx/include/__cxx03/__bit/bit_width.h (revision ce7771902dc50d900de639d499a60486b83f70e0)
1e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
2e78f53d1SNikolas Klauser //
3e78f53d1SNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4e78f53d1SNikolas Klauser // See https://llvm.org/LICENSE.txt for license information.
5e78f53d1SNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6e78f53d1SNikolas Klauser //
7e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
8e78f53d1SNikolas Klauser 
9*ce777190SNikolas Klauser #ifndef _LIBCPP___CXX03___BIT_BIT_WIDTH_H
10*ce777190SNikolas Klauser #define _LIBCPP___CXX03___BIT_BIT_WIDTH_H
11e78f53d1SNikolas Klauser 
1273fbae83SNikolas Klauser #include <__cxx03/__bit/bit_log2.h>
1373fbae83SNikolas Klauser #include <__cxx03/__concepts/arithmetic.h>
1473fbae83SNikolas Klauser #include <__cxx03/__config>
15e78f53d1SNikolas Klauser 
16e78f53d1SNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17e78f53d1SNikolas Klauser #  pragma GCC system_header
18e78f53d1SNikolas Klauser #endif
19e78f53d1SNikolas Klauser 
20e78f53d1SNikolas Klauser #if _LIBCPP_STD_VER >= 20
21e78f53d1SNikolas Klauser 
22e78f53d1SNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD
23e78f53d1SNikolas Klauser 
24e78f53d1SNikolas Klauser template <__libcpp_unsigned_integer _Tp>
25e78f53d1SNikolas Klauser [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
26e78f53d1SNikolas Klauser   return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
27e78f53d1SNikolas Klauser }
28e78f53d1SNikolas Klauser 
29e78f53d1SNikolas Klauser _LIBCPP_END_NAMESPACE_STD
30e78f53d1SNikolas Klauser 
31e78f53d1SNikolas Klauser #endif // _LIBCPP_STD_VER >= 20
32e78f53d1SNikolas Klauser 
33*ce777190SNikolas Klauser #endif // _LIBCPP___CXX03___BIT_BIT_WIDTH_H
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