blob: f29b57949c60b7cf6f82198aef9b3e4acd88bde8 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
|
//===----------------------------------------------------------------------===//
//
// 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>
#include <limits>
#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
|
