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