1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
//===----------------------------------------------------------------------===//
//
// 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_INPLACE_MERGE_H
#define _LIBCPP___ALGORITHM_INPLACE_MERGE_H
#include <__config>
#include <__algorithm/comp_ref_type.h>
#include <__algorithm/comp.h>
#include <__algorithm/lower_bound.h>
#include <__algorithm/min.h>
#include <__algorithm/move.h>
#include <__algorithm/rotate.h>
#include <__algorithm/upper_bound.h>
#include <__iterator/iterator_traits.h>
#include <__utility/swap.h>
#include <memory>
#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 _Predicate>
class __invert // invert the sense of a comparison
{
private:
_Predicate __p_;
public:
_LIBCPP_INLINE_VISIBILITY __invert() {}
_LIBCPP_INLINE_VISIBILITY
explicit __invert(_Predicate __p) : __p_(__p) {}
template <class _T1>
_LIBCPP_INLINE_VISIBILITY
bool operator()(const _T1& __x) {return !__p_(__x);}
template <class _T1, class _T2>
_LIBCPP_INLINE_VISIBILITY
bool operator()(const _T1& __x, const _T2& __y) {return __p_(__y, __x);}
};
template <class _Compare, class _InputIterator1, class _InputIterator2,
class _OutputIterator>
void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2,
_OutputIterator __result, _Compare __comp)
{
for (; __first1 != __last1; ++__result)
{
if (__first2 == __last2)
{
_VSTD::move(__first1, __last1, __result);
return;
}
if (__comp(*__first2, *__first1))
{
*__result = _VSTD::move(*__first2);
++__first2;
}
else
{
*__result = _VSTD::move(*__first1);
++__first1;
}
}
// __first2 through __last2 are already in the right spot.
}
template <class _Compare, class _BidirectionalIterator>
void
__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
_Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
{
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
__destruct_n __d(0);
unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
if (__len1 <= __len2)
{
value_type* __p = __buff;
for (_BidirectionalIterator __i = __first; __i != __middle; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p)
::new ((void*)__p) value_type(_VSTD::move(*__i));
_VSTD::__half_inplace_merge<_Compare>(__buff, __p, __middle, __last, __first, __comp);
}
else
{
value_type* __p = __buff;
for (_BidirectionalIterator __i = __middle; __i != __last; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p)
::new ((void*)__p) value_type(_VSTD::move(*__i));
typedef reverse_iterator<_BidirectionalIterator> _RBi;
typedef reverse_iterator<value_type*> _Rv;
typedef __invert<_Compare> _Inverted;
_VSTD::__half_inplace_merge<_Inverted>(_Rv(__p), _Rv(__buff),
_RBi(__middle), _RBi(__first),
_RBi(__last), _Inverted(__comp));
}
}
template <class _Compare, class _BidirectionalIterator>
void
__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
_Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
{
typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
while (true)
{
// if __middle == __last, we're done
if (__len2 == 0)
return;
if (__len1 <= __buff_size || __len2 <= __buff_size)
return _VSTD::__buffered_inplace_merge<_Compare>
(__first, __middle, __last, __comp, __len1, __len2, __buff);
// shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
for (; true; ++__first, (void) --__len1)
{
if (__len1 == 0)
return;
if (__comp(*__middle, *__first))
break;
}
// __first < __middle < __last
// *__first > *__middle
// partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
// all elements in:
// [__first, __m1) <= [__middle, __m2)
// [__middle, __m2) < [__m1, __middle)
// [__m1, __middle) <= [__m2, __last)
// and __m1 or __m2 is in the middle of its range
_BidirectionalIterator __m1; // "median" of [__first, __middle)
_BidirectionalIterator __m2; // "median" of [__middle, __last)
difference_type __len11; // distance(__first, __m1)
difference_type __len21; // distance(__middle, __m2)
// binary search smaller range
if (__len1 < __len2)
{ // __len >= 1, __len2 >= 2
__len21 = __len2 / 2;
__m2 = __middle;
_VSTD::advance(__m2, __len21);
__m1 = _VSTD::__upper_bound<_Compare>(__first, __middle, *__m2, __comp);
__len11 = _VSTD::distance(__first, __m1);
}
else
{
if (__len1 == 1)
{ // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
// It is known *__first > *__middle
swap(*__first, *__middle);
return;
}
// __len1 >= 2, __len2 >= 1
__len11 = __len1 / 2;
__m1 = __first;
_VSTD::advance(__m1, __len11);
__m2 = _VSTD::__lower_bound<_Compare>(__middle, __last, *__m1, __comp);
__len21 = _VSTD::distance(__middle, __m2);
}
difference_type __len12 = __len1 - __len11; // distance(__m1, __middle)
difference_type __len22 = __len2 - __len21; // distance(__m2, __last)
// [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
// swap middle two partitions
__middle = _VSTD::rotate(__m1, __middle, __m2);
// __len12 and __len21 now have swapped meanings
// merge smaller range with recursive call and larger with tail recursion elimination
if (__len11 + __len21 < __len12 + __len22)
{
_VSTD::__inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
// _VSTD::__inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
__first = __middle;
__middle = __m2;
__len1 = __len12;
__len2 = __len22;
}
else
{
_VSTD::__inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
// _VSTD::__inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
__last = __middle;
__middle = __m1;
__len1 = __len11;
__len2 = __len21;
}
}
}
template <class _BidirectionalIterator, class _Compare>
inline _LIBCPP_INLINE_VISIBILITY
void
inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
_Compare __comp)
{
typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
difference_type __len1 = _VSTD::distance(__first, __middle);
difference_type __len2 = _VSTD::distance(__middle, __last);
difference_type __buf_size = _VSTD::min(__len1, __len2);
pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
__buf.first, __buf.second);
}
template <class _BidirectionalIterator>
inline _LIBCPP_INLINE_VISIBILITY
void
inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
{
_VSTD::inplace_merge(__first, __middle, __last,
__less<typename iterator_traits<_BidirectionalIterator>::value_type>());
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_INPLACE_MERGE_H
|
