xref: /freebsd-src/contrib/llvm-project/libcxx/include/__bit/rotate.h (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1*bdd1243dSDimitry Andric //===----------------------------------------------------------------------===//
2*bdd1243dSDimitry Andric //
3*bdd1243dSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*bdd1243dSDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*bdd1243dSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*bdd1243dSDimitry Andric //
7*bdd1243dSDimitry Andric //===----------------------------------------------------------------------===//
8*bdd1243dSDimitry Andric 
9*bdd1243dSDimitry Andric #ifndef _LIBCPP___BIT_ROTATE_H
10*bdd1243dSDimitry Andric #define _LIBCPP___BIT_ROTATE_H
11*bdd1243dSDimitry Andric 
12*bdd1243dSDimitry Andric #include <__concepts/arithmetic.h>
13*bdd1243dSDimitry Andric #include <__config>
14*bdd1243dSDimitry Andric #include <__type_traits/is_unsigned_integer.h>
15*bdd1243dSDimitry Andric #include <limits>
16*bdd1243dSDimitry Andric 
17*bdd1243dSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18*bdd1243dSDimitry Andric #  pragma GCC system_header
19*bdd1243dSDimitry Andric #endif
20*bdd1243dSDimitry Andric 
21*bdd1243dSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
22*bdd1243dSDimitry Andric 
23*bdd1243dSDimitry Andric template<class _Tp>
24*bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
25*bdd1243dSDimitry Andric _Tp __rotr(_Tp __t, unsigned int __cnt) _NOEXCEPT
26*bdd1243dSDimitry Andric {
27*bdd1243dSDimitry Andric     static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type");
28*bdd1243dSDimitry Andric     const unsigned int __dig = numeric_limits<_Tp>::digits;
29*bdd1243dSDimitry Andric     if ((__cnt % __dig) == 0)
30*bdd1243dSDimitry Andric         return __t;
31*bdd1243dSDimitry Andric     return (__t >> (__cnt % __dig)) | (__t << (__dig - (__cnt % __dig)));
32*bdd1243dSDimitry Andric }
33*bdd1243dSDimitry Andric 
34*bdd1243dSDimitry Andric #if _LIBCPP_STD_VER >= 20
35*bdd1243dSDimitry Andric 
36*bdd1243dSDimitry Andric template <__libcpp_unsigned_integer _Tp>
37*bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotl(_Tp __t, unsigned int __cnt) noexcept {
38*bdd1243dSDimitry Andric   const unsigned int __dig = numeric_limits<_Tp>::digits;
39*bdd1243dSDimitry Andric   if ((__cnt % __dig) == 0)
40*bdd1243dSDimitry Andric     return __t;
41*bdd1243dSDimitry Andric   return (__t << (__cnt % __dig)) | (__t >> (__dig - (__cnt % __dig)));
42*bdd1243dSDimitry Andric }
43*bdd1243dSDimitry Andric 
44*bdd1243dSDimitry Andric template <__libcpp_unsigned_integer _Tp>
45*bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotr(_Tp __t, unsigned int __cnt) noexcept {
46*bdd1243dSDimitry Andric   return std::__rotr(__t, __cnt);
47*bdd1243dSDimitry Andric }
48*bdd1243dSDimitry Andric 
49*bdd1243dSDimitry Andric #endif // _LIBCPP_STD_VER >= 20
50*bdd1243dSDimitry Andric 
51*bdd1243dSDimitry Andric _LIBCPP_END_NAMESPACE_STD
52*bdd1243dSDimitry Andric 
53*bdd1243dSDimitry Andric #endif // _LIBCPP___BIT_ROTATE_H
54