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_STABLE_SORT_H
10 #define _LIBCPP___ALGORITHM_STABLE_SORT_H
11
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__algorithm/inplace_merge.h>
15 #include <__algorithm/iterator_operations.h>
16 #include <__algorithm/sort.h>
17 #include <__config>
18 #include <__iterator/iterator_traits.h>
19 #include <__memory/destruct_n.h>
20 #include <__memory/temporary_buffer.h>
21 #include <__memory/unique_ptr.h>
22 #include <__type_traits/is_trivially_copy_assignable.h>
23 #include <__utility/move.h>
24 #include <__utility/pair.h>
25 #include <new>
26
27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28 # pragma GCC system_header
29 #endif
30
31 _LIBCPP_BEGIN_NAMESPACE_STD
32
33 template <class _AlgPolicy, class _Compare, class _BidirectionalIterator>
34 _LIBCPP_HIDE_FROM_ABI
__insertion_sort_move(_BidirectionalIterator __first1,_BidirectionalIterator __last1,typename iterator_traits<_BidirectionalIterator>::value_type * __first2,_Compare __comp)35 void __insertion_sort_move(_BidirectionalIterator __first1, _BidirectionalIterator __last1,
36 typename iterator_traits<_BidirectionalIterator>::value_type* __first2, _Compare __comp) {
37 using _Ops = _IterOps<_AlgPolicy>;
38
39 typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
40 if (__first1 != __last1) {
41 __destruct_n __d(0);
42 unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
43 value_type* __last2 = __first2;
44 ::new ((void*)__last2) value_type(_Ops::__iter_move(__first1));
45 __d.template __incr<value_type>();
46 for (++__last2; ++__first1 != __last1; ++__last2) {
47 value_type* __j2 = __last2;
48 value_type* __i2 = __j2;
49 if (__comp(*__first1, *--__i2)) {
50 ::new ((void*)__j2) value_type(std::move(*__i2));
51 __d.template __incr<value_type>();
52 for (--__j2; __i2 != __first2 && __comp(*__first1, *--__i2); --__j2)
53 *__j2 = std::move(*__i2);
54 *__j2 = _Ops::__iter_move(__first1);
55 } else {
56 ::new ((void*)__j2) value_type(_Ops::__iter_move(__first1));
57 __d.template __incr<value_type>();
58 }
59 }
60 __h.release();
61 }
62 }
63
64 template <class _AlgPolicy, class _Compare, class _InputIterator1, class _InputIterator2>
65 _LIBCPP_HIDE_FROM_ABI void
__merge_move_construct(_InputIterator1 __first1,_InputIterator1 __last1,_InputIterator2 __first2,_InputIterator2 __last2,typename iterator_traits<_InputIterator1>::value_type * __result,_Compare __comp)66 __merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
67 _InputIterator2 __first2, _InputIterator2 __last2,
68 typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
69 {
70 using _Ops = _IterOps<_AlgPolicy>;
71
72 typedef typename iterator_traits<_InputIterator1>::value_type value_type;
73 __destruct_n __d(0);
74 unique_ptr<value_type, __destruct_n&> __h(__result, __d);
75 for (; true; ++__result)
76 {
77 if (__first1 == __last1)
78 {
79 for (; __first2 != __last2; ++__first2, (void) ++__result, __d.template __incr<value_type>())
80 ::new ((void*)__result) value_type(_Ops::__iter_move(__first2));
81 __h.release();
82 return;
83 }
84 if (__first2 == __last2)
85 {
86 for (; __first1 != __last1; ++__first1, (void) ++__result, __d.template __incr<value_type>())
87 ::new ((void*)__result) value_type(_Ops::__iter_move(__first1));
88 __h.release();
89 return;
90 }
91 if (__comp(*__first2, *__first1))
92 {
93 ::new ((void*)__result) value_type(_Ops::__iter_move(__first2));
94 __d.template __incr<value_type>();
95 ++__first2;
96 }
97 else
98 {
99 ::new ((void*)__result) value_type(_Ops::__iter_move(__first1));
100 __d.template __incr<value_type>();
101 ++__first1;
102 }
103 }
104 }
105
106 template <class _AlgPolicy, class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
107 _LIBCPP_HIDE_FROM_ABI void
__merge_move_assign(_InputIterator1 __first1,_InputIterator1 __last1,_InputIterator2 __first2,_InputIterator2 __last2,_OutputIterator __result,_Compare __comp)108 __merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
109 _InputIterator2 __first2, _InputIterator2 __last2,
110 _OutputIterator __result, _Compare __comp)
111 {
112 using _Ops = _IterOps<_AlgPolicy>;
113
114 for (; __first1 != __last1; ++__result)
115 {
116 if (__first2 == __last2)
117 {
118 for (; __first1 != __last1; ++__first1, (void) ++__result)
119 *__result = _Ops::__iter_move(__first1);
120 return;
121 }
122 if (__comp(*__first2, *__first1))
123 {
124 *__result = _Ops::__iter_move(__first2);
125 ++__first2;
126 }
127 else
128 {
129 *__result = _Ops::__iter_move(__first1);
130 ++__first1;
131 }
132 }
133 for (; __first2 != __last2; ++__first2, (void) ++__result)
134 *__result = _Ops::__iter_move(__first2);
135 }
136
137 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
138 void
139 __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
140 typename iterator_traits<_RandomAccessIterator>::difference_type __len,
141 typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
142
143 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
144 void
__stable_sort_move(_RandomAccessIterator __first1,_RandomAccessIterator __last1,_Compare __comp,typename iterator_traits<_RandomAccessIterator>::difference_type __len,typename iterator_traits<_RandomAccessIterator>::value_type * __first2)145 __stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
146 typename iterator_traits<_RandomAccessIterator>::difference_type __len,
147 typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
148 {
149 using _Ops = _IterOps<_AlgPolicy>;
150
151 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
152 switch (__len)
153 {
154 case 0:
155 return;
156 case 1:
157 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1));
158 return;
159 case 2:
160 __destruct_n __d(0);
161 unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
162 if (__comp(*--__last1, *__first1))
163 {
164 ::new ((void*)__first2) value_type(_Ops::__iter_move(__last1));
165 __d.template __incr<value_type>();
166 ++__first2;
167 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1));
168 }
169 else
170 {
171 ::new ((void*)__first2) value_type(_Ops::__iter_move(__first1));
172 __d.template __incr<value_type>();
173 ++__first2;
174 ::new ((void*)__first2) value_type(_Ops::__iter_move(__last1));
175 }
176 __h2.release();
177 return;
178 }
179 if (__len <= 8)
180 {
181 std::__insertion_sort_move<_AlgPolicy, _Compare>(__first1, __last1, __first2, __comp);
182 return;
183 }
184 typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
185 _RandomAccessIterator __m = __first1 + __l2;
186 std::__stable_sort<_AlgPolicy, _Compare>(__first1, __m, __comp, __l2, __first2, __l2);
187 std::__stable_sort<_AlgPolicy, _Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
188 std::__merge_move_construct<_AlgPolicy, _Compare>(__first1, __m, __m, __last1, __first2, __comp);
189 }
190
191 template <class _Tp>
192 struct __stable_sort_switch
193 {
194 static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
195 };
196
197 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
198 void
__stable_sort(_RandomAccessIterator __first,_RandomAccessIterator __last,_Compare __comp,typename iterator_traits<_RandomAccessIterator>::difference_type __len,typename iterator_traits<_RandomAccessIterator>::value_type * __buff,ptrdiff_t __buff_size)199 __stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
200 typename iterator_traits<_RandomAccessIterator>::difference_type __len,
201 typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
202 {
203 typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
204 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
205 switch (__len)
206 {
207 case 0:
208 case 1:
209 return;
210 case 2:
211 if (__comp(*--__last, *__first))
212 _IterOps<_AlgPolicy>::iter_swap(__first, __last);
213 return;
214 }
215 if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
216 {
217 std::__insertion_sort<_AlgPolicy, _Compare>(__first, __last, __comp);
218 return;
219 }
220 typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
221 _RandomAccessIterator __m = __first + __l2;
222 if (__len <= __buff_size)
223 {
224 __destruct_n __d(0);
225 unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
226 std::__stable_sort_move<_AlgPolicy, _Compare>(__first, __m, __comp, __l2, __buff);
227 __d.__set(__l2, (value_type*)nullptr);
228 std::__stable_sort_move<_AlgPolicy, _Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
229 __d.__set(__len, (value_type*)nullptr);
230 std::__merge_move_assign<_AlgPolicy, _Compare>(
231 __buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
232 // _VSTD::__merge<_Compare>(move_iterator<value_type*>(__buff),
233 // move_iterator<value_type*>(__buff + __l2),
234 // move_iterator<_RandomAccessIterator>(__buff + __l2),
235 // move_iterator<_RandomAccessIterator>(__buff + __len),
236 // __first, __comp);
237 return;
238 }
239 std::__stable_sort<_AlgPolicy, _Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
240 std::__stable_sort<_AlgPolicy, _Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
241 std::__inplace_merge<_AlgPolicy>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
242 }
243
244 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
245 inline _LIBCPP_HIDE_FROM_ABI
__stable_sort_impl(_RandomAccessIterator __first,_RandomAccessIterator __last,_Compare & __comp)246 void __stable_sort_impl(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
247 using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
248 using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
249
250 difference_type __len = __last - __first;
251 pair<value_type*, ptrdiff_t> __buf(0, 0);
252 unique_ptr<value_type, __return_temporary_buffer> __h;
253 if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value)) {
254 // TODO: Remove the use of std::get_temporary_buffer
255 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
256 __buf = std::get_temporary_buffer<value_type>(__len);
257 _LIBCPP_SUPPRESS_DEPRECATED_POP
258 __h.reset(__buf.first);
259 }
260
261 std::__stable_sort<_AlgPolicy, __comp_ref_type<_Compare> >(__first, __last, __comp, __len, __buf.first, __buf.second);
262 }
263
264 template <class _RandomAccessIterator, class _Compare>
265 inline _LIBCPP_HIDE_FROM_ABI
stable_sort(_RandomAccessIterator __first,_RandomAccessIterator __last,_Compare __comp)266 void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
267 std::__stable_sort_impl<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
268 }
269
270 template <class _RandomAccessIterator>
271 inline _LIBCPP_HIDE_FROM_ABI
stable_sort(_RandomAccessIterator __first,_RandomAccessIterator __last)272 void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last) {
273 std::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
274 }
275
276 _LIBCPP_END_NAMESPACE_STD
277
278 #endif // _LIBCPP___ALGORITHM_STABLE_SORT_H
279