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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___CXX03___BIT_ROTATE_H
#define _LIBCPP___CXX03___BIT_ROTATE_H
#include <__cxx03/__concepts/arithmetic.h>
#include <__cxx03/__config>
#include <__cxx03/__type_traits/is_unsigned_integer.h>
#include <__cxx03/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.
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotl(_Tp __x, int __s) _NOEXCEPT {
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotl requires an unsigned integer type");
const int __N = numeric_limits<_Tp>::digits;
int __r = __s % __N;
if (__r == 0)
return __x;
if (__r > 0)
return (__x << __r) | (__x >> (__N - __r));
return (__x >> -__r) | (__x << (__N + __r));
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp __rotr(_Tp __x, int __s) _NOEXCEPT {
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type");
const int __N = numeric_limits<_Tp>::digits;
int __r = __s % __N;
if (__r == 0)
return __x;
if (__r > 0)
return (__x >> __r) | (__x << (__N - __r));
return (__x << -__r) | (__x >> (__N + __r));
}
#if _LIBCPP_STD_VER >= 20
template <__libcpp_unsigned_integer _Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotl(_Tp __t, int __cnt) noexcept {
return std::__rotl(__t, __cnt);
}
template <__libcpp_unsigned_integer _Tp>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotr(_Tp __t, int __cnt) noexcept {
return std::__rotr(__t, __cnt);
}
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___CXX03___BIT_ROTATE_H
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