blob: a558d6194270e8a834cb4b33e50d745e3e2ea77e (
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
|
//===----------------------------------------------------------------------===//
//
// 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_CEIL_H
#define _LIBCPP___BIT_BIT_CEIL_H
#include <__assert>
#include <__bit/countl.h>
#include <__concepts/arithmetic.h>
#include <__config>
#include <limits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
template <__libcpp_unsigned_integer _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_ceil(_Tp __t) noexcept {
if (__t < 2)
return 1;
const unsigned __n = numeric_limits<_Tp>::digits - std::countl_zero((_Tp)(__t - 1u));
_LIBCPP_ASSERT(__n != numeric_limits<_Tp>::digits, "Bad input to bit_ceil");
if constexpr (sizeof(_Tp) >= sizeof(unsigned))
return _Tp{1} << __n;
else {
const unsigned __extra = numeric_limits<unsigned>::digits - numeric_limits<_Tp>::digits;
const unsigned __retVal = 1u << (__n + __extra);
return (_Tp)(__retVal >> __extra);
}
}
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___BIT_BIT_CEIL_H
|
