xref: /freebsd/contrib/llvm-project/libcxx/include/__bit/bit_width.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1bdd1243dSDimitry Andric //===----------------------------------------------------------------------===//
2bdd1243dSDimitry Andric //
3bdd1243dSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4bdd1243dSDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5bdd1243dSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6bdd1243dSDimitry Andric //
7bdd1243dSDimitry Andric //===----------------------------------------------------------------------===//
8bdd1243dSDimitry Andric 
9bdd1243dSDimitry Andric #ifndef _LIBCPP___BIT_BIT_WIDTH_H
10bdd1243dSDimitry Andric #define _LIBCPP___BIT_BIT_WIDTH_H
11bdd1243dSDimitry Andric 
12bdd1243dSDimitry Andric #include <__bit/bit_log2.h>
13bdd1243dSDimitry Andric #include <__concepts/arithmetic.h>
14bdd1243dSDimitry Andric #include <__config>
15bdd1243dSDimitry Andric 
16bdd1243dSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17bdd1243dSDimitry Andric #  pragma GCC system_header
18bdd1243dSDimitry Andric #endif
19bdd1243dSDimitry Andric 
20bdd1243dSDimitry Andric #if _LIBCPP_STD_VER >= 20
21bdd1243dSDimitry Andric 
22bdd1243dSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
23bdd1243dSDimitry Andric 
24bdd1243dSDimitry Andric template <__libcpp_unsigned_integer _Tp>
bit_width(_Tp __t)25*0fca6ea1SDimitry Andric [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
26bdd1243dSDimitry Andric   return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
27bdd1243dSDimitry Andric }
28bdd1243dSDimitry Andric 
29bdd1243dSDimitry Andric _LIBCPP_END_NAMESPACE_STD
30bdd1243dSDimitry Andric 
31bdd1243dSDimitry Andric #endif // _LIBCPP_STD_VER >= 20
32bdd1243dSDimitry Andric 
33bdd1243dSDimitry Andric #endif // _LIBCPP___BIT_BIT_WIDTH_H
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