| //===----------------------------------------------------------------------===// |
| // |
| // 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___RANDOM_LOG2_H |
| #define _LIBCPP___RANDOM_LOG2_H |
| |
| #include <__config> |
| #include <cstddef> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <unsigned long long _Xp, size_t _Rp> |
| struct __log2_imp |
| { |
| static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp |
| : __log2_imp<_Xp, _Rp - 1>::value; |
| }; |
| |
| template <unsigned long long _Xp> |
| struct __log2_imp<_Xp, 0> |
| { |
| static const size_t value = 0; |
| }; |
| |
| template <size_t _Rp> |
| struct __log2_imp<0, _Rp> |
| { |
| static const size_t value = _Rp + 1; |
| }; |
| |
| template <class _UIntType, _UIntType _Xp> |
| struct __log2 |
| { |
| static const size_t value = __log2_imp<_Xp, |
| sizeof(_UIntType) * __CHAR_BIT__ - 1>::value; |
| }; |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___RANDOM_LOG2_H |
