bit_width.h

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___BIT_BIT_WIDTH_H
#define _LIBCPP___BIT_BIT_WIDTH_H

#include <__bit/bit_log2.h>
#include <__concepts/arithmetic.h>
#include <__config>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

#if _LIBCPP_STD_VER >= 20

_LIBCPP_BEGIN_NAMESPACE_STD

template <__libcpp_unsigned_integer _Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept {
  return __t == 0 ? 0 : std::__bit_log2(__t) + 1;
}

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER >= 20

#endif // _LIBCPP___BIT_BIT_WIDTH_H