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_SORT_H
10 #define _LIBCPP___ALGORITHM_SORT_H
11 
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__algorithm/min_element.h>
15 #include <__algorithm/partial_sort.h>
16 #include <__algorithm/unwrap_iter.h>
17 #include <__bits>
18 #include <__config>
19 #include <__debug>
20 #include <__debug_utils/randomize_range.h>
21 #include <__functional/operations.h>
22 #include <__functional/ranges_operations.h>
23 #include <__iterator/iterator_traits.h>
24 #include <__utility/swap.h>
25 #include <climits>
26 #include <memory>
27 
28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
29 #  pragma GCC system_header
30 #endif
31 
32 _LIBCPP_BEGIN_NAMESPACE_STD
33 
34 // stable, 2-3 compares, 0-2 swaps
35 
36 template <class _Compare, class _ForwardIterator>
37 _LIBCPP_CONSTEXPR_AFTER_CXX11 unsigned __sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z,
38                                                _Compare __c) {
39   unsigned __r = 0;
40   if (!__c(*__y, *__x))   // if x <= y
41   {
42     if (!__c(*__z, *__y)) // if y <= z
43       return __r;         // x <= y && y <= z
44                           // x <= y && y > z
45     swap(*__y, *__z);     // x <= z && y < z
46     __r = 1;
47     if (__c(*__y, *__x))  // if x > y
48     {
49       swap(*__x, *__y);   // x < y && y <= z
50       __r = 2;
51     }
52     return __r;           // x <= y && y < z
53   }
54   if (__c(*__z, *__y))    // x > y, if y > z
55   {
56     swap(*__x, *__z);     // x < y && y < z
57     __r = 1;
58     return __r;
59   }
60   swap(*__x, *__y);       // x > y && y <= z
61   __r = 1;                // x < y && x <= z
62   if (__c(*__z, *__y))    // if y > z
63   {
64     swap(*__y, *__z);     // x <= y && y < z
65     __r = 2;
66   }
67   return __r;
68 }                         // x <= y && y <= z
69 
70 // stable, 3-6 compares, 0-5 swaps
71 
72 template <class _Compare, class _ForwardIterator>
73 unsigned __sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3, _ForwardIterator __x4,
74                  _Compare __c) {
75   unsigned __r = _VSTD::__sort3<_Compare>(__x1, __x2, __x3, __c);
76   if (__c(*__x4, *__x3)) {
77     swap(*__x3, *__x4);
78     ++__r;
79     if (__c(*__x3, *__x2)) {
80       swap(*__x2, *__x3);
81       ++__r;
82       if (__c(*__x2, *__x1)) {
83         swap(*__x1, *__x2);
84         ++__r;
85       }
86     }
87   }
88   return __r;
89 }
90 
91 // stable, 4-10 compares, 0-9 swaps
92 
93 template <class _Compare, class _ForwardIterator>
94 _LIBCPP_HIDDEN unsigned __sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
95                                 _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c) {
96   unsigned __r = _VSTD::__sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
97   if (__c(*__x5, *__x4)) {
98     swap(*__x4, *__x5);
99     ++__r;
100     if (__c(*__x4, *__x3)) {
101       swap(*__x3, *__x4);
102       ++__r;
103       if (__c(*__x3, *__x2)) {
104         swap(*__x2, *__x3);
105         ++__r;
106         if (__c(*__x2, *__x1)) {
107           swap(*__x1, *__x2);
108           ++__r;
109         }
110       }
111     }
112   }
113   return __r;
114 }
115 
116 // The comparator being simple is a prerequisite for using the branchless optimization.
117 template <class _Tp>
118 struct __is_simple_comparator : false_type {};
119 template <class _Tp>
120 struct __is_simple_comparator<__less<_Tp>&> : true_type {};
121 template <class _Tp>
122 struct __is_simple_comparator<less<_Tp>&> : true_type {};
123 template <class _Tp>
124 struct __is_simple_comparator<greater<_Tp>&> : true_type {};
125 #if _LIBCPP_STD_VER > 17
126 template <>
127 struct __is_simple_comparator<ranges::less&> : true_type {};
128 template <>
129 struct __is_simple_comparator<ranges::greater&> : true_type {};
130 #endif
131 
132 template <class _Compare, class _Iter, class _Tp = typename iterator_traits<_Iter>::value_type>
133 using __use_branchless_sort =
134     integral_constant<bool, __is_cpp17_contiguous_iterator<_Iter>::value && sizeof(_Tp) <= sizeof(void*) &&
135                                 is_arithmetic<_Tp>::value && __is_simple_comparator<_Compare>::value>;
136 
137 // Ensures that __c(*__x, *__y) is true by swapping *__x and *__y if necessary.
138 template <class _Compare, class _RandomAccessIterator>
139 inline _LIBCPP_HIDE_FROM_ABI void __cond_swap(_RandomAccessIterator __x, _RandomAccessIterator __y, _Compare __c) {
140   using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
141   bool __r = __c(*__x, *__y);
142   value_type __tmp = __r ? *__x : *__y;
143   *__y = __r ? *__y : *__x;
144   *__x = __tmp;
145 }
146 
147 // Ensures that *__x, *__y and *__z are ordered according to the comparator __c,
148 // under the assumption that *__y and *__z are already ordered.
149 template <class _Compare, class _RandomAccessIterator>
150 inline _LIBCPP_HIDE_FROM_ABI void __partially_sorted_swap(_RandomAccessIterator __x, _RandomAccessIterator __y,
151                                                           _RandomAccessIterator __z, _Compare __c) {
152   using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
153   bool __r = __c(*__z, *__x);
154   value_type __tmp = __r ? *__z : *__x;
155   *__z = __r ? *__x : *__z;
156   __r = __c(__tmp, *__y);
157   *__x = __r ? *__x : *__y;
158   *__y = __r ? *__y : __tmp;
159 }
160 
161 template <class _Compare, class _RandomAccessIterator>
162 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
163 __sort3_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
164                          _Compare __c) {
165   _VSTD::__cond_swap<_Compare>(__x2, __x3, __c);
166   _VSTD::__partially_sorted_swap<_Compare>(__x1, __x2, __x3, __c);
167 }
168 
169 template <class _Compare, class _RandomAccessIterator>
170 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<!__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
171 __sort3_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
172                          _Compare __c) {
173   _VSTD::__sort3<_Compare>(__x1, __x2, __x3, __c);
174 }
175 
176 template <class _Compare, class _RandomAccessIterator>
177 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
178 __sort4_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
179                          _RandomAccessIterator __x4, _Compare __c) {
180   _VSTD::__cond_swap<_Compare>(__x1, __x3, __c);
181   _VSTD::__cond_swap<_Compare>(__x2, __x4, __c);
182   _VSTD::__cond_swap<_Compare>(__x1, __x2, __c);
183   _VSTD::__cond_swap<_Compare>(__x3, __x4, __c);
184   _VSTD::__cond_swap<_Compare>(__x2, __x3, __c);
185 }
186 
187 template <class _Compare, class _RandomAccessIterator>
188 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<!__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
189 __sort4_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
190                          _RandomAccessIterator __x4, _Compare __c) {
191   _VSTD::__sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
192 }
193 
194 template <class _Compare, class _RandomAccessIterator>
195 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
196 __sort5_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
197                          _RandomAccessIterator __x4, _RandomAccessIterator __x5, _Compare __c) {
198   _VSTD::__cond_swap<_Compare>(__x1, __x2, __c);
199   _VSTD::__cond_swap<_Compare>(__x4, __x5, __c);
200   _VSTD::__partially_sorted_swap<_Compare>(__x3, __x4, __x5, __c);
201   _VSTD::__cond_swap<_Compare>(__x2, __x5, __c);
202   _VSTD::__partially_sorted_swap<_Compare>(__x1, __x3, __x4, __c);
203   _VSTD::__partially_sorted_swap<_Compare>(__x2, __x3, __x4, __c);
204 }
205 
206 template <class _Compare, class _RandomAccessIterator>
207 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<!__use_branchless_sort<_Compare, _RandomAccessIterator>::value, void>
208 __sort5_maybe_branchless(_RandomAccessIterator __x1, _RandomAccessIterator __x2, _RandomAccessIterator __x3,
209                          _RandomAccessIterator __x4, _RandomAccessIterator __x5, _Compare __c) {
210   _VSTD::__sort5<_Compare>(__x1, __x2, __x3, __x4, __x5, __c);
211 }
212 
213 // Assumes size > 0
214 template <class _Compare, class _BidirectionalIterator>
215 _LIBCPP_CONSTEXPR_AFTER_CXX11 void __selection_sort(_BidirectionalIterator __first, _BidirectionalIterator __last,
216                                                     _Compare __comp) {
217   _BidirectionalIterator __lm1 = __last;
218   for (--__lm1; __first != __lm1; ++__first) {
219     _BidirectionalIterator __i = _VSTD::min_element(__first, __last, __comp);
220     if (__i != __first)
221       swap(*__first, *__i);
222   }
223 }
224 
225 template <class _Compare, class _BidirectionalIterator>
226 void __insertion_sort(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) {
227   typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
228   if (__first != __last) {
229     _BidirectionalIterator __i = __first;
230     for (++__i; __i != __last; ++__i) {
231       _BidirectionalIterator __j = __i;
232       value_type __t(_VSTD::move(*__j));
233       for (_BidirectionalIterator __k = __i; __k != __first && __comp(__t, *--__k); --__j)
234         *__j = _VSTD::move(*__k);
235       *__j = _VSTD::move(__t);
236     }
237   }
238 }
239 
240 template <class _Compare, class _RandomAccessIterator>
241 void __insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
242   typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
243   typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
244   _RandomAccessIterator __j = __first + difference_type(2);
245   _VSTD::__sort3_maybe_branchless<_Compare>(__first, __first + difference_type(1), __j, __comp);
246   for (_RandomAccessIterator __i = __j + difference_type(1); __i != __last; ++__i) {
247     if (__comp(*__i, *__j)) {
248       value_type __t(_VSTD::move(*__i));
249       _RandomAccessIterator __k = __j;
250       __j = __i;
251       do {
252         *__j = _VSTD::move(*__k);
253         __j = __k;
254       } while (__j != __first && __comp(__t, *--__k));
255       *__j = _VSTD::move(__t);
256     }
257     __j = __i;
258   }
259 }
260 
261 template <class _Compare, class _RandomAccessIterator>
262 bool __insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
263   typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
264   switch (__last - __first) {
265   case 0:
266   case 1:
267     return true;
268   case 2:
269     if (__comp(*--__last, *__first))
270       swap(*__first, *__last);
271     return true;
272   case 3:
273     _VSTD::__sort3_maybe_branchless<_Compare>(__first, __first + difference_type(1), --__last, __comp);
274     return true;
275   case 4:
276     _VSTD::__sort4_maybe_branchless<_Compare>(__first, __first + difference_type(1), __first + difference_type(2),
277                                               --__last, __comp);
278     return true;
279   case 5:
280     _VSTD::__sort5_maybe_branchless<_Compare>(__first, __first + difference_type(1), __first + difference_type(2),
281                                               __first + difference_type(3), --__last, __comp);
282     return true;
283   }
284   typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
285   _RandomAccessIterator __j = __first + difference_type(2);
286   _VSTD::__sort3_maybe_branchless<_Compare>(__first, __first + difference_type(1), __j, __comp);
287   const unsigned __limit = 8;
288   unsigned __count = 0;
289   for (_RandomAccessIterator __i = __j + difference_type(1); __i != __last; ++__i) {
290     if (__comp(*__i, *__j)) {
291       value_type __t(_VSTD::move(*__i));
292       _RandomAccessIterator __k = __j;
293       __j = __i;
294       do {
295         *__j = _VSTD::move(*__k);
296         __j = __k;
297       } while (__j != __first && __comp(__t, *--__k));
298       *__j = _VSTD::move(__t);
299       if (++__count == __limit)
300         return ++__i == __last;
301     }
302     __j = __i;
303   }
304   return true;
305 }
306 
307 template <class _Compare, class _BidirectionalIterator>
308 void __insertion_sort_move(_BidirectionalIterator __first1, _BidirectionalIterator __last1,
309                            typename iterator_traits<_BidirectionalIterator>::value_type* __first2, _Compare __comp) {
310   typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
311   if (__first1 != __last1) {
312     __destruct_n __d(0);
313     unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
314     value_type* __last2 = __first2;
315     ::new ((void*)__last2) value_type(_VSTD::move(*__first1));
316     __d.template __incr<value_type>();
317     for (++__last2; ++__first1 != __last1; ++__last2) {
318       value_type* __j2 = __last2;
319       value_type* __i2 = __j2;
320       if (__comp(*__first1, *--__i2)) {
321         ::new ((void*)__j2) value_type(_VSTD::move(*__i2));
322         __d.template __incr<value_type>();
323         for (--__j2; __i2 != __first2 && __comp(*__first1, *--__i2); --__j2)
324           *__j2 = _VSTD::move(*__i2);
325         *__j2 = _VSTD::move(*__first1);
326       } else {
327         ::new ((void*)__j2) value_type(_VSTD::move(*__first1));
328         __d.template __incr<value_type>();
329       }
330     }
331     __h.release();
332   }
333 }
334 
335 template <class _Compare, class _RandomAccessIterator>
336 void __introsort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
337                  typename iterator_traits<_RandomAccessIterator>::difference_type __depth) {
338   typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
339   typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
340   const difference_type __limit =
341       is_trivially_copy_constructible<value_type>::value && is_trivially_copy_assignable<value_type>::value ? 30 : 6;
342   while (true) {
343   __restart:
344     difference_type __len = __last - __first;
345     switch (__len) {
346     case 0:
347     case 1:
348       return;
349     case 2:
350       if (__comp(*--__last, *__first))
351         swap(*__first, *__last);
352       return;
353     case 3:
354       _VSTD::__sort3_maybe_branchless<_Compare>(__first, __first + difference_type(1), --__last, __comp);
355       return;
356     case 4:
357       _VSTD::__sort4_maybe_branchless<_Compare>(__first, __first + difference_type(1), __first + difference_type(2),
358                                                 --__last, __comp);
359       return;
360     case 5:
361       _VSTD::__sort5_maybe_branchless<_Compare>(__first, __first + difference_type(1), __first + difference_type(2),
362                                                 __first + difference_type(3), --__last, __comp);
363       return;
364     }
365     if (__len <= __limit) {
366       _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
367       return;
368     }
369     // __len > 5
370     if (__depth == 0) {
371       // Fallback to heap sort as Introsort suggests.
372       _VSTD::__partial_sort<_Compare>(__first, __last, __last, __comp);
373       return;
374     }
375     --__depth;
376     _RandomAccessIterator __m = __first;
377     _RandomAccessIterator __lm1 = __last;
378     --__lm1;
379     unsigned __n_swaps;
380     {
381       difference_type __delta;
382       if (__len >= 1000) {
383         __delta = __len / 2;
384         __m += __delta;
385         __delta /= 2;
386         __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m + __delta, __lm1, __comp);
387       } else {
388         __delta = __len / 2;
389         __m += __delta;
390         __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
391       }
392     }
393     // *__m is median
394     // partition [__first, __m) < *__m and *__m <= [__m, __last)
395     // (this inhibits tossing elements equivalent to __m around unnecessarily)
396     _RandomAccessIterator __i = __first;
397     _RandomAccessIterator __j = __lm1;
398     // j points beyond range to be tested, *__m is known to be <= *__lm1
399     // The search going up is known to be guarded but the search coming down isn't.
400     // Prime the downward search with a guard.
401     if (!__comp(*__i, *__m)) // if *__first == *__m
402     {
403       // *__first == *__m, *__first doesn't go in first part
404       // manually guard downward moving __j against __i
405       while (true) {
406         if (__i == --__j) {
407           // *__first == *__m, *__m <= all other elements
408           // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
409           ++__i; // __first + 1
410           __j = __last;
411           if (!__comp(*__first, *--__j)) // we need a guard if *__first == *(__last-1)
412           {
413             while (true) {
414               if (__i == __j)
415                 return; // [__first, __last) all equivalent elements
416               if (__comp(*__first, *__i)) {
417                 swap(*__i, *__j);
418                 ++__n_swaps;
419                 ++__i;
420                 break;
421               }
422               ++__i;
423             }
424           }
425           // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
426           if (__i == __j)
427             return;
428           while (true) {
429             while (!__comp(*__first, *__i))
430               ++__i;
431             while (__comp(*__first, *--__j))
432               ;
433             if (__i >= __j)
434               break;
435             swap(*__i, *__j);
436             ++__n_swaps;
437             ++__i;
438           }
439           // [__first, __i) == *__first and *__first < [__i, __last)
440           // The first part is sorted, sort the second part
441           // _VSTD::__sort<_Compare>(__i, __last, __comp);
442           __first = __i;
443           goto __restart;
444         }
445         if (__comp(*__j, *__m)) {
446           swap(*__i, *__j);
447           ++__n_swaps;
448           break; // found guard for downward moving __j, now use unguarded partition
449         }
450       }
451     }
452     // It is known that *__i < *__m
453     ++__i;
454     // j points beyond range to be tested, *__m is known to be <= *__lm1
455     // if not yet partitioned...
456     if (__i < __j) {
457       // known that *(__i - 1) < *__m
458       // known that __i <= __m
459       while (true) {
460         // __m still guards upward moving __i
461         while (__comp(*__i, *__m))
462           ++__i;
463         // It is now known that a guard exists for downward moving __j
464         while (!__comp(*--__j, *__m))
465           ;
466         if (__i > __j)
467           break;
468         swap(*__i, *__j);
469         ++__n_swaps;
470         // It is known that __m != __j
471         // If __m just moved, follow it
472         if (__m == __i)
473           __m = __j;
474         ++__i;
475       }
476     }
477     // [__first, __i) < *__m and *__m <= [__i, __last)
478     if (__i != __m && __comp(*__m, *__i)) {
479       swap(*__i, *__m);
480       ++__n_swaps;
481     }
482     // [__first, __i) < *__i and *__i <= [__i+1, __last)
483     // If we were given a perfect partition, see if insertion sort is quick...
484     if (__n_swaps == 0) {
485       bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
486       if (_VSTD::__insertion_sort_incomplete<_Compare>(__i + difference_type(1), __last, __comp)) {
487         if (__fs)
488           return;
489         __last = __i;
490         continue;
491       } else {
492         if (__fs) {
493           __first = ++__i;
494           continue;
495         }
496       }
497     }
498     // sort smaller range with recursive call and larger with tail recursion elimination
499     if (__i - __first < __last - __i) {
500       _VSTD::__introsort<_Compare>(__first, __i, __comp, __depth);
501       __first = ++__i;
502     } else {
503       _VSTD::__introsort<_Compare>(__i + difference_type(1), __last, __comp, __depth);
504       __last = __i;
505     }
506   }
507 }
508 
509 template <typename _Number>
510 inline _LIBCPP_HIDE_FROM_ABI _Number __log2i(_Number __n) {
511   if (__n == 0)
512     return 0;
513   if (sizeof(__n) <= sizeof(unsigned))
514     return sizeof(unsigned) * CHAR_BIT - 1 - __libcpp_clz(static_cast<unsigned>(__n));
515   if (sizeof(__n) <= sizeof(unsigned long))
516     return sizeof(unsigned long) * CHAR_BIT - 1 - __libcpp_clz(static_cast<unsigned long>(__n));
517   if (sizeof(__n) <= sizeof(unsigned long long))
518     return sizeof(unsigned long long) * CHAR_BIT - 1 - __libcpp_clz(static_cast<unsigned long long>(__n));
519 
520   _Number __log2 = 0;
521   while (__n > 1) {
522     __log2++;
523     __n >>= 1;
524   }
525   return __log2;
526 }
527 
528 template <class _Compare, class _RandomAccessIterator>
529 void __sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
530   typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
531   difference_type __depth_limit = 2 * __log2i(__last - __first);
532   _VSTD::__introsort<_Compare>(__first, __last, __comp, __depth_limit);
533 }
534 
535 template <class _Compare, class _Tp>
536 inline _LIBCPP_INLINE_VISIBILITY void __sort(_Tp** __first, _Tp** __last, __less<_Tp*>&) {
537   __less<uintptr_t> __comp;
538   _VSTD::__sort<__less<uintptr_t>&, uintptr_t*>((uintptr_t*)__first, (uintptr_t*)__last, __comp);
539 }
540 
541 extern template _LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&);
542 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
543 extern template _LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&);
544 #endif
545 extern template _LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&);
546 extern template _LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&);
547 extern template _LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&);
548 extern template _LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&);
549 extern template _LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&);
550 extern template _LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&);
551 extern template _LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&);
552 extern template _LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&);
553 extern template _LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&);
554 extern template _LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&);
555 extern template _LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&);
556 extern template _LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&);
557 extern template _LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&);
558 
559 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&);
560 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
561 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&);
562 #endif
563 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&);
564 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&);
565 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&);
566 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&);
567 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&);
568 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&);
569 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&);
570 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&);
571 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&);
572 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&);
573 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&);
574 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&);
575 extern template _LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&);
576 
577 extern template _LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&);
578 
579 template <class _RandomAccessIterator, class _Comp>
580 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
581 void __sort_impl(_RandomAccessIterator __first, _RandomAccessIterator __last, _Comp& __comp) {
582   std::__debug_randomize_range(__first, __last);
583   using _Comp_ref = typename __comp_ref_type<_Comp>::type;
584   if (__libcpp_is_constant_evaluated()) {
585     std::__partial_sort<_Comp_ref>(__first, __last, __last, _Comp_ref(__comp));
586   } else {
587     std::__sort<_Comp_ref>(std::__unwrap_iter(__first), std::__unwrap_iter(__last), _Comp_ref(__comp));
588   }
589 }
590 
591 template <class _RandomAccessIterator, class _Comp>
592 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
593 void sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Comp __comp) {
594   std::__sort_impl(std::move(__first), std::move(__last), __comp);
595 }
596 
597 template <class _RandomAccessIterator>
598 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
599 void sort(_RandomAccessIterator __first, _RandomAccessIterator __last) {
600   std::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
601 }
602 
603 _LIBCPP_END_NAMESPACE_STD
604 
605 #endif // _LIBCPP___ALGORITHM_SORT_H
606