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//===----------------------------------------------------------------------===//
//
// 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_ROTATE_H
#define _LIBCPP___BIT_ROTATE_H
#include <__config>
#include <__type_traits/integer_traits.h>
#include <limits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
// Writing two full functions for rotl and rotr makes it easier for the compiler
// to optimize the code. On x86 this function becomes the ROL instruction and
// the rotr function becomes the ROR instruction.
#if _LIBCPP_STD_VER >= 20
template <__unsigned_integer _Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotl(_Tp __t, int __cnt) noexcept {
const int __n = numeric_limits<_Tp>::digits;
int __r = __cnt % __n;
if (__r == 0)
return __t;
if (__r > 0)
return (__t << __r) | (__t >> (__n - __r));
return (__t >> -__r) | (__t << (__n + __r));
}
template <__unsigned_integer _Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotr(_Tp __t, int __cnt) noexcept {
const int __n = numeric_limits<_Tp>::digits;
int __r = __cnt % __n;
if (__r == 0)
return __t;
if (__r > 0)
return (__t >> __r) | (__t << (__n - __r));
return (__t << -__r) | (__t >> (__n + __r));
}
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___BIT_ROTATE_H
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