1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___BIT_BIT_WIDTH_H 10 #define _LIBCPP___BIT_BIT_WIDTH_H 11 12 #include <__bit/bit_log2.h> 13 #include <__concepts/arithmetic.h> 14 #include <__config> 15 16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17 # pragma GCC system_header 18 #endif 19 20 #if _LIBCPP_STD_VER >= 20 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 template <__libcpp_unsigned_integer _Tp> 25 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept { 26 return __t == 0 ? 0 : std::__bit_log2(__t) + 1; 27 } 28 29 _LIBCPP_END_NAMESPACE_STD 30 31 #endif // _LIBCPP_STD_VER >= 20 32 33 #endif // _LIBCPP___BIT_BIT_WIDTH_H 34