1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___ALGORITHM_ROTATE_H
10#define _LIBCPP___ALGORITHM_ROTATE_H
11
12#include <__algorithm/copy.h>
13#include <__algorithm/copy_backward.h>
14#include <__algorithm/iterator_operations.h>
15#include <__algorithm/min.h>
16#include <__algorithm/move.h>
17#include <__algorithm/move_backward.h>
18#include <__algorithm/swap_ranges.h>
19#include <__config>
20#include <__fwd/bit_reference.h>
21#include <__iterator/iterator_traits.h>
22#include <__type_traits/is_trivially_assignable.h>
23#include <__utility/move.h>
24#include <__utility/pair.h>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27# pragma GCC system_header
28#endif
29
30_LIBCPP_PUSH_MACROS
31#include <__undef_macros>
32
33_LIBCPP_BEGIN_NAMESPACE_STD
34
35template <class _AlgPolicy, class _ForwardIterator>
36_LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator __rotate_left(_ForwardIterator __first, _ForwardIterator __last) {
37 typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
38 using _Ops = _IterOps<_AlgPolicy>;
39
40 value_type __tmp = _Ops::__iter_move(__first);
41 _ForwardIterator __lm1 = std::__move<_AlgPolicy>(_Ops::next(__first), __last, __first).__out_;
42 *__lm1 = std::move(__tmp);
43 return __lm1;
44}
45
46template <class _AlgPolicy, class _BidirectionalIterator>
47_LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator
48__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last) {
49 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
50 using _Ops = _IterOps<_AlgPolicy>;
51
52 _BidirectionalIterator __lm1 = _Ops::prev(__last);
53 value_type __tmp = _Ops::__iter_move(__lm1);
54 _BidirectionalIterator __fp1 = std::__move_backward<_AlgPolicy>(__first, __lm1, std::move(__last)).__out_;
55 *__first = std::move(__tmp);
56 return __fp1;
57}
58
59template <class _AlgPolicy, class _ForwardIterator>
60_LIBCPP_CONSTEXPR_SINCE_CXX17 _ForwardIterator
61__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
62 _ForwardIterator __i = __middle;
63 while (true) {
64 _IterOps<_AlgPolicy>::iter_swap(__first, __i);
65 ++__first;
66 if (++__i == __last)
67 break;
68 if (__first == __middle)
69 __middle = __i;
70 }
71 _ForwardIterator __r = __first;
72 if (__first != __middle) {
73 __i = __middle;
74 while (true) {
75 _IterOps<_AlgPolicy>::iter_swap(__first, __i);
76 ++__first;
77 if (++__i == __last) {
78 if (__first == __middle)
79 break;
80 __i = __middle;
81 } else if (__first == __middle)
82 __middle = __i;
83 }
84 }
85 return __r;
86}
87
88template <class _AlgPolicy, class _Iter, class _Sent>
89_LIBCPP_CONSTEXPR_SINCE_CXX17 _Iter __rotate_random_access(_Iter __first, _Iter __middle, _Sent __sent) {
90 auto __left = _IterOps<_AlgPolicy>::distance(__first, __middle);
91 auto __right = _IterOps<_AlgPolicy>::distance(__middle, __sent);
92 auto __last = __first + __right;
93
94 auto __min_len = std::min(__left, __right);
95
96 while (__min_len > 0) {
97 if (__left <= __right) {
98 do {
99 std::__swap_ranges<_AlgPolicy>(__first, __first + __left, __first + __left);
100 __first += __left;
101 __right -= __left;
102 } while (__left <= __right);
103 __min_len = __right;
104 } else {
105 do {
106 std::__swap_ranges<_AlgPolicy>(__first + (__left - __right), __first + __left, __first + __left);
107 __left -= __right;
108 } while (__left > __right);
109 __min_len = __left;
110 }
111 }
112 return __last;
113}
114
115template <class _AlgPolicy, class _ForwardIterator>
116inline _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
117__rotate_impl(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, std::forward_iterator_tag) {
118 typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
119 if (is_trivially_move_assignable<value_type>::value) {
120 if (_IterOps<_AlgPolicy>::next(__first) == __middle)
121 return std::__rotate_left<_AlgPolicy>(__first, __last);
122 }
123 return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
124}
125
126template <class _AlgPolicy, class _BidirectionalIterator>
127inline _LIBCPP_CONSTEXPR_SINCE_CXX14 _BidirectionalIterator __rotate_impl(
128 _BidirectionalIterator __first,
129 _BidirectionalIterator __middle,
130 _BidirectionalIterator __last,
131 bidirectional_iterator_tag) {
132 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
133 if (is_trivially_move_assignable<value_type>::value) {
134 if (_IterOps<_AlgPolicy>::next(__first) == __middle)
135 return std::__rotate_left<_AlgPolicy>(__first, __last);
136 if (_IterOps<_AlgPolicy>::next(__middle) == __last)
137 return std::__rotate_right<_AlgPolicy>(__first, __last);
138 }
139 return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
140}
141
142template <class _AlgPolicy, class _RandomAccessIterator>
143inline _LIBCPP_CONSTEXPR_SINCE_CXX14 _RandomAccessIterator __rotate_impl(
144 _RandomAccessIterator __first,
145 _RandomAccessIterator __middle,
146 _RandomAccessIterator __last,
147 random_access_iterator_tag) {
148 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
149 if (is_trivially_move_assignable<value_type>::value) {
150 if (_IterOps<_AlgPolicy>::next(__first) == __middle)
151 return std::__rotate_left<_AlgPolicy>(__first, __last);
152 if (_IterOps<_AlgPolicy>::next(__middle) == __last)
153 return std::__rotate_right<_AlgPolicy>(__first, __last);
154 return std::__rotate_random_access<_AlgPolicy>(__first, __middle, __last);
155 }
156 return std::__rotate_forward<_AlgPolicy>(__first, __middle, __last);
157}
158
159template <class _AlgPolicy, class _Iterator, class _Sentinel>
160_LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iterator, _Iterator>
161__rotate(_Iterator __first, _Iterator __middle, _Sentinel __last) {
162 using _Ret = pair<_Iterator, _Iterator>;
163 _Iterator __last_iter = _IterOps<_AlgPolicy>::next(__middle, __last);
164
165 if (__first == __middle)
166 return _Ret(__last_iter, __last_iter);
167 if (__middle == __last)
168 return _Ret(std::move(__first), std::move(__last_iter));
169
170 using _IterCategory = typename _IterOps<_AlgPolicy>::template __iterator_category<_Iterator>;
171 auto __result = std::__rotate_impl<_AlgPolicy>(std::move(__first), std::move(__middle), __last_iter, _IterCategory());
172
173 return _Ret(std::move(__result), std::move(__last_iter));
174}
175
176template <class, class _Cp>
177_LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__bit_iterator<_Cp, false>, __bit_iterator<_Cp, false> >
178__rotate(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __middle, __bit_iterator<_Cp, false> __last) {
179 using _I1 = __bit_iterator<_Cp, false>;
180 using difference_type = typename _I1::difference_type;
181 difference_type __d1 = __middle - __first;
182 difference_type __d2 = __last - __middle;
183 _I1 __r = __first + __d2;
184 while (__d1 != 0 && __d2 != 0) {
185 if (__d1 <= __d2) {
186 if (__d1 <= __bit_array<_Cp>::capacity()) {
187 __bit_array<_Cp> __b(__d1);
188 std::copy(__first, __middle, __b.begin());
189 std::copy(__b.begin(), __b.end(), std::copy(__middle, __last, __first));
190 break;
191 } else {
192 __bit_iterator<_Cp, false> __mp = std::swap_ranges(__first, __middle, __middle);
193 __first = __middle;
194 __middle = __mp;
195 __d2 -= __d1;
196 }
197 } else {
198 if (__d2 <= __bit_array<_Cp>::capacity()) {
199 __bit_array<_Cp> __b(__d2);
200 std::copy(__middle, __last, __b.begin());
201 std::copy_backward(__b.begin(), __b.end(), std::copy_backward(__first, __middle, __last));
202 break;
203 } else {
204 __bit_iterator<_Cp, false> __mp = __first + __d2;
205 std::swap_ranges(__first, __mp, __middle);
206 __first = __mp;
207 __d1 -= __d2;
208 }
209 }
210 }
211 return std::make_pair(__r, __last);
212}
213
214template <class _ForwardIterator>
215inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
216rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last) {
217 return std::__rotate<_ClassicAlgPolicy>(std::move(__first), std::move(__middle), std::move(__last)).first;
218}
219
220_LIBCPP_END_NAMESPACE_STD
221
222_LIBCPP_POP_MACROS
223
224#endif // _LIBCPP___ALGORITHM_ROTATE_H
225