xref: /openbsd-src/gnu/llvm/libcxx/include/__bit/has_single_bit.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
1*4bdff4beSrobert //===----------------------------------------------------------------------===//
2*4bdff4beSrobert //
3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information.
5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*4bdff4beSrobert //
7*4bdff4beSrobert //===----------------------------------------------------------------------===//
8*4bdff4beSrobert 
9*4bdff4beSrobert #ifndef _LIBCPP___BIT_HAS_SINGLE_BIT_H
10*4bdff4beSrobert #define _LIBCPP___BIT_HAS_SINGLE_BIT_H
11*4bdff4beSrobert 
12*4bdff4beSrobert #include <__concepts/arithmetic.h>
13*4bdff4beSrobert #include <__config>
14*4bdff4beSrobert 
15*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16*4bdff4beSrobert #  pragma GCC system_header
17*4bdff4beSrobert #endif
18*4bdff4beSrobert 
19*4bdff4beSrobert _LIBCPP_PUSH_MACROS
20*4bdff4beSrobert #include <__undef_macros>
21*4bdff4beSrobert 
22*4bdff4beSrobert #if _LIBCPP_STD_VER >= 20
23*4bdff4beSrobert 
24*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD
25*4bdff4beSrobert 
26*4bdff4beSrobert template <__libcpp_unsigned_integer _Tp>
has_single_bit(_Tp __t)27*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI constexpr bool has_single_bit(_Tp __t) noexcept {
28*4bdff4beSrobert   return __t != 0 && (((__t & (__t - 1)) == 0));
29*4bdff4beSrobert }
30*4bdff4beSrobert 
31*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD
32*4bdff4beSrobert 
33*4bdff4beSrobert #endif // _LIBCPP_STD_VER >= 20
34*4bdff4beSrobert 
35*4bdff4beSrobert _LIBCPP_POP_MACROS
36*4bdff4beSrobert 
37*4bdff4beSrobert #endif // _LIBCPP___BIT_HAS_SINGLE_BIT_H
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