//===----------------------------------------------------------------------===//
//
// 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___ALGORITHM_ROTATE_H
#define _LIBCPP___ALGORITHM_ROTATE_H
#include <__algorithm/iterator_operations.h>
#include <__algorithm/move.h>
#include <__algorithm/move_backward.h>
#include <__algorithm/swap_ranges.h>
#include <__config>
#include <__iterator/iterator_traits.h>
#include <__type_traits/is_trivially_assignable.h>
#include <__utility/move.h>
#include <__utility/pair.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _AlgPolicy, class _ForwardIterator>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
__rotate_left(_ForwardIterator __first, _ForwardIterator __last) {
typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
using _Ops = _IterOps<_AlgPolicy>;
value_type __tmp = _Ops::__iter_move(__first);
_ForwardIterator __lm1 = std::__move<_AlgPolicy>(_Ops::next(__first), __last, __first).second;
*__lm1 = std::move(__tmp);
return __lm1;
}
template <class _AlgPolicy, class _BidirectionalIterator>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator
__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last) {
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
using _Ops = _IterOps<_AlgPolicy>;
_BidirectionalIterator __lm1 = _Ops::prev(__last);
value_type __tmp = _Ops::__iter_move(__lm1);
_BidirectionalIterator __fp1 = std::__move_backward<_AlgPolicy>(__first, __lm1, std::move(__last)).second;
*__first = std::move(__tmp);
return __fp1;
}
template <class _AlgPolicy, class _ForwardIterator>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _ForwardIterator
__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
_ForwardIterator __i = __middle;
while (true) {
_IterOps<_AlgPolicy>::iter_swap(__first, __i);
++__first;
if (++__i == __last)
break;
if (__first == __middle)
__middle = __i;
}
_ForwardIterator __r = __first;
if (__first != __middle) {
__i = __middle;
while (true) {
_IterOps<_AlgPolicy>::iter_swap(__first, __i);
++__first;
if (++__i == __last) {
if (__first == __middle)
break;
__i = __middle;
} else if (__first == __middle)
__middle = __i;
}
}
return __r;
}
template <typename _Integral>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _Integral __algo_gcd(_Integral __x, _Integral __y) {
do {
_Integral __t = __x % __y;
__x = __y;
__y = __t;
} while (__y);
return __x;
}
template <class _AlgPolicy, typename _RandomAccessIterator>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _RandomAccessIterator
__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) {
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
using _Ops = _IterOps<_AlgPolicy>;
const difference_type __m1 = __middle - __first;
const difference_type __m2 = _Ops::distance(__middle, __last);
if (__m1 == __m2) {
std::__swap_ranges<_AlgPolicy>(__first, __middle, __middle, __last);
return __middle;
}
const difference_type __g = std::__algo_gcd(__m1, __m2);
for (_RandomAccessIterator __p = __first + __g; __p != __first;) {
value_type __t(_Ops::__iter_move(--__p));
_RandomAccessIterator __p1 = __p;
_RandomAccessIterator __p2 = __p1 + __m1;
do {
*__p1 = _Ops::__iter_move(__p2);
__p1 = __p2;
const difference_type __d = _Ops::distance(__p2, __last);
if (__m1 < __d)
__p2 += __m1;
else
__p2 = __first + (__m1 - __d);
} while (__p2 != __p);
*__p1 = std::move(__t);
}
return __first + __m2;
}
template <class _AlgPolicy, class _ForwardIterator>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
__rotate_impl(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, std::forward_iterator_tag) {
typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
if (is_trivially_move_assignable<value_type>::value) {
if (_IterOps<_AlgPolicy>::next(__first) == __middle)
return std::__rotate_left<_AlgPolicy>(__first, __last);
}
return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
}
template <class _AlgPolicy, class _BidirectionalIterator>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator __rotate_impl(
_BidirectionalIterator __first,
_BidirectionalIterator __middle,
_BidirectionalIterator __last,
bidirectional_iterator_tag) {
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
if (is_trivially_move_assignable<value_type>::value) {
if (_IterOps<_AlgPolicy>::next(__first) == __middle)
return std::__rotate_left<_AlgPolicy>(__first, __last);
if (_IterOps<_AlgPolicy>::next(__middle) == __last)
return std::__rotate_right<_AlgPolicy>(__first, __last);
}
return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
}
template <class _AlgPolicy, class _RandomAccessIterator>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _RandomAccessIterator __rotate_impl(
_RandomAccessIterator __first,
_RandomAccessIterator __middle,
_RandomAccessIterator __last,
random_access_iterator_tag) {
typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
if (is_trivially_move_assignable<value_type>::value) {
if (_IterOps<_AlgPolicy>::next(__first) == __middle)
return std::__rotate_left<_AlgPolicy>(__first, __last);
if (_IterOps<_AlgPolicy>::next(__middle) == __last)
return std::__rotate_right<_AlgPolicy>(__first, __last);
return std::__rotate_gcd<_AlgPolicy>(__first, __middle, __last);
}
return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
}
template <class _AlgPolicy, class _Iterator, class _Sentinel>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iterator, _Iterator>
__rotate(_Iterator __first, _Iterator __middle, _Sentinel __last) {
using _Ret = pair<_Iterator, _Iterator>;
_Iterator __last_iter = _IterOps<_AlgPolicy>::next(__middle, __last);
if (__first == __middle)
return _Ret(__last_iter, __last_iter);
if (__middle == __last)
return _Ret(std::move(__first), std::move(__last_iter));
using _IterCategory = typename _IterOps<_AlgPolicy>::template __iterator_category<_Iterator>;
auto __result = std::__rotate_impl<_AlgPolicy>(std::move(__first), std::move(__middle), __last_iter, _IterCategory());
return _Ret(std::move(__result), std::move(__last_iter));
}
template <class _ForwardIterator>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
return std::__rotate<_ClassicAlgPolicy>(std::move(__first), std::move(__middle), std::move(__last)).first;
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_ROTATE_H
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