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1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
11 #define _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
12 
13 #include <__algorithm/copy.h>
14 #include <__algorithm/move.h>
15 #include <__algorithm/unwrap_iter.h>
16 #include <__algorithm/unwrap_range.h>
17 #include <__config>
18 #include <__iterator/iterator_traits.h>
19 #include <__iterator/reverse_iterator.h>
20 #include <__memory/addressof.h>
21 #include <__memory/allocator_traits.h>
22 #include <__memory/construct_at.h>
23 #include <__memory/pointer_traits.h>
24 #include <__memory/voidify.h>
25 #include <__type_traits/extent.h>
26 #include <__type_traits/is_array.h>
27 #include <__type_traits/is_constant_evaluated.h>
28 #include <__type_traits/is_trivially_copy_assignable.h>
29 #include <__type_traits/is_trivially_copy_constructible.h>
30 #include <__type_traits/is_trivially_move_assignable.h>
31 #include <__type_traits/is_trivially_move_constructible.h>
32 #include <__type_traits/is_unbounded_array.h>
33 #include <__type_traits/negation.h>
34 #include <__type_traits/remove_const.h>
35 #include <__type_traits/remove_extent.h>
36 #include <__utility/exception_guard.h>
37 #include <__utility/move.h>
38 #include <__utility/pair.h>
39 #include <new>
40 
41 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
42 #  pragma GCC system_header
43 #endif
44 
45 _LIBCPP_BEGIN_NAMESPACE_STD
46 
47 struct __always_false {
48   template <class... _Args>
operator__always_false49   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool operator()(_Args&&...) const _NOEXCEPT {
50     return false;
51   }
52 };
53 
54 // uninitialized_copy
55 
56 template <class _ValueType, class _InputIterator, class _Sentinel1, class _ForwardIterator, class _EndPredicate>
__uninitialized_copy(_InputIterator __ifirst,_Sentinel1 __ilast,_ForwardIterator __ofirst,_EndPredicate __stop_copying)57 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator> __uninitialized_copy(
58     _InputIterator __ifirst, _Sentinel1 __ilast, _ForwardIterator __ofirst, _EndPredicate __stop_copying) {
59   _ForwardIterator __idx = __ofirst;
60 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
61   try {
62 #endif
63     for (; __ifirst != __ilast && !__stop_copying(__idx); ++__ifirst, (void)++__idx)
64       ::new (_VSTD::__voidify(*__idx)) _ValueType(*__ifirst);
65 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
66   } catch (...) {
67     _VSTD::__destroy(__ofirst, __idx);
68     throw;
69   }
70 #endif
71 
72   return pair<_InputIterator, _ForwardIterator>(_VSTD::move(__ifirst), _VSTD::move(__idx));
73 }
74 
75 template <class _InputIterator, class _ForwardIterator>
76 _LIBCPP_HIDE_FROM_ABI
uninitialized_copy(_InputIterator __ifirst,_InputIterator __ilast,_ForwardIterator __ofirst)77 _ForwardIterator uninitialized_copy(_InputIterator __ifirst, _InputIterator __ilast,
78                                     _ForwardIterator __ofirst) {
79   typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
80   auto __result = std::__uninitialized_copy<_ValueType>(
81       std::move(__ifirst), std::move(__ilast), std::move(__ofirst), __always_false());
82   return _VSTD::move(__result.second);
83 }
84 
85 // uninitialized_copy_n
86 
87 template <class _ValueType, class _InputIterator, class _Size, class _ForwardIterator, class _EndPredicate>
__uninitialized_copy_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst,_EndPredicate __stop_copying)88 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator> __uninitialized_copy_n(
89     _InputIterator __ifirst, _Size __n, _ForwardIterator __ofirst, _EndPredicate __stop_copying) {
90   _ForwardIterator __idx = __ofirst;
91 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
92   try {
93 #endif
94     for (; __n > 0 && !__stop_copying(__idx); ++__ifirst, (void)++__idx, (void)--__n)
95       ::new (_VSTD::__voidify(*__idx)) _ValueType(*__ifirst);
96 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
97   } catch (...) {
98     _VSTD::__destroy(__ofirst, __idx);
99     throw;
100   }
101 #endif
102 
103   return pair<_InputIterator, _ForwardIterator>(_VSTD::move(__ifirst), _VSTD::move(__idx));
104 }
105 
106 template <class _InputIterator, class _Size, class _ForwardIterator>
uninitialized_copy_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst)107 inline _LIBCPP_HIDE_FROM_ABI _ForwardIterator uninitialized_copy_n(_InputIterator __ifirst, _Size __n,
108                                                                    _ForwardIterator __ofirst) {
109   typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
110   auto __result =
111       std::__uninitialized_copy_n<_ValueType>(std::move(__ifirst), __n, std::move(__ofirst), __always_false());
112   return _VSTD::move(__result.second);
113 }
114 
115 // uninitialized_fill
116 
117 template <class _ValueType, class _ForwardIterator, class _Sentinel, class _Tp>
118 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_fill(_ForwardIterator __first,_Sentinel __last,const _Tp & __x)119 _ForwardIterator __uninitialized_fill(_ForwardIterator __first, _Sentinel __last, const _Tp& __x)
120 {
121     _ForwardIterator __idx = __first;
122 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
123     try
124     {
125 #endif
126         for (; __idx != __last; ++__idx)
127             ::new (_VSTD::__voidify(*__idx)) _ValueType(__x);
128 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
129     }
130     catch (...)
131     {
132         _VSTD::__destroy(__first, __idx);
133         throw;
134     }
135 #endif
136 
137     return __idx;
138 }
139 
140 template <class _ForwardIterator, class _Tp>
141 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_fill(_ForwardIterator __first,_ForwardIterator __last,const _Tp & __x)142 void uninitialized_fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __x)
143 {
144     typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
145     (void)_VSTD::__uninitialized_fill<_ValueType>(__first, __last, __x);
146 }
147 
148 // uninitialized_fill_n
149 
150 template <class _ValueType, class _ForwardIterator, class _Size, class _Tp>
151 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_fill_n(_ForwardIterator __first,_Size __n,const _Tp & __x)152 _ForwardIterator __uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
153 {
154     _ForwardIterator __idx = __first;
155 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
156     try
157     {
158 #endif
159         for (; __n > 0; ++__idx, (void) --__n)
160             ::new (_VSTD::__voidify(*__idx)) _ValueType(__x);
161 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
162     }
163     catch (...)
164     {
165         _VSTD::__destroy(__first, __idx);
166         throw;
167     }
168 #endif
169 
170     return __idx;
171 }
172 
173 template <class _ForwardIterator, class _Size, class _Tp>
174 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_fill_n(_ForwardIterator __first,_Size __n,const _Tp & __x)175 _ForwardIterator uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x)
176 {
177     typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
178     return _VSTD::__uninitialized_fill_n<_ValueType>(__first, __n, __x);
179 }
180 
181 #if _LIBCPP_STD_VER >= 17
182 
183 // uninitialized_default_construct
184 
185 template <class _ValueType, class _ForwardIterator, class _Sentinel>
186 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_default_construct(_ForwardIterator __first,_Sentinel __last)187 _ForwardIterator __uninitialized_default_construct(_ForwardIterator __first, _Sentinel __last) {
188     auto __idx = __first;
189 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
190     try {
191 #endif
192     for (; __idx != __last; ++__idx)
193         ::new (_VSTD::__voidify(*__idx)) _ValueType;
194 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
195     } catch (...) {
196         _VSTD::__destroy(__first, __idx);
197         throw;
198     }
199 #endif
200 
201     return __idx;
202 }
203 
204 template <class _ForwardIterator>
205 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_default_construct(_ForwardIterator __first,_ForwardIterator __last)206 void uninitialized_default_construct(_ForwardIterator __first, _ForwardIterator __last) {
207     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
208     (void)_VSTD::__uninitialized_default_construct<_ValueType>(
209         _VSTD::move(__first), _VSTD::move(__last));
210 }
211 
212 // uninitialized_default_construct_n
213 
214 template <class _ValueType, class _ForwardIterator, class _Size>
215 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_default_construct_n(_ForwardIterator __first,_Size __n)216 _ForwardIterator __uninitialized_default_construct_n(_ForwardIterator __first, _Size __n) {
217     auto __idx = __first;
218 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
219     try {
220 #endif
221     for (; __n > 0; ++__idx, (void) --__n)
222         ::new (_VSTD::__voidify(*__idx)) _ValueType;
223 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
224     } catch (...) {
225         _VSTD::__destroy(__first, __idx);
226         throw;
227     }
228 #endif
229 
230     return __idx;
231 }
232 
233 template <class _ForwardIterator, class _Size>
234 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_default_construct_n(_ForwardIterator __first,_Size __n)235 _ForwardIterator uninitialized_default_construct_n(_ForwardIterator __first, _Size __n) {
236     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
237     return _VSTD::__uninitialized_default_construct_n<_ValueType>(_VSTD::move(__first), __n);
238 }
239 
240 // uninitialized_value_construct
241 
242 template <class _ValueType, class _ForwardIterator, class _Sentinel>
243 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_value_construct(_ForwardIterator __first,_Sentinel __last)244 _ForwardIterator __uninitialized_value_construct(_ForwardIterator __first, _Sentinel __last) {
245     auto __idx = __first;
246 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
247     try {
248 #endif
249     for (; __idx != __last; ++__idx)
250         ::new (_VSTD::__voidify(*__idx)) _ValueType();
251 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
252     } catch (...) {
253         _VSTD::__destroy(__first, __idx);
254         throw;
255     }
256 #endif
257 
258     return __idx;
259 }
260 
261 template <class _ForwardIterator>
262 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_value_construct(_ForwardIterator __first,_ForwardIterator __last)263 void uninitialized_value_construct(_ForwardIterator __first, _ForwardIterator __last) {
264     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
265     (void)_VSTD::__uninitialized_value_construct<_ValueType>(
266         _VSTD::move(__first), _VSTD::move(__last));
267 }
268 
269 // uninitialized_value_construct_n
270 
271 template <class _ValueType, class _ForwardIterator, class _Size>
272 inline _LIBCPP_HIDE_FROM_ABI
__uninitialized_value_construct_n(_ForwardIterator __first,_Size __n)273 _ForwardIterator __uninitialized_value_construct_n(_ForwardIterator __first, _Size __n) {
274     auto __idx = __first;
275 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
276     try {
277 #endif
278     for (; __n > 0; ++__idx, (void) --__n)
279         ::new (_VSTD::__voidify(*__idx)) _ValueType();
280 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
281     } catch (...) {
282         _VSTD::__destroy(__first, __idx);
283         throw;
284     }
285 #endif
286 
287     return __idx;
288 }
289 
290 template <class _ForwardIterator, class _Size>
291 inline _LIBCPP_HIDE_FROM_ABI
uninitialized_value_construct_n(_ForwardIterator __first,_Size __n)292 _ForwardIterator uninitialized_value_construct_n(_ForwardIterator __first, _Size __n) {
293     using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
294     return std::__uninitialized_value_construct_n<_ValueType>(_VSTD::move(__first), __n);
295 }
296 
297 // uninitialized_move
298 
299 template <class _ValueType,
300           class _InputIterator,
301           class _Sentinel1,
302           class _ForwardIterator,
303           class _EndPredicate,
304           class _IterMove>
__uninitialized_move(_InputIterator __ifirst,_Sentinel1 __ilast,_ForwardIterator __ofirst,_EndPredicate __stop_moving,_IterMove __iter_move)305 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator> __uninitialized_move(
306     _InputIterator __ifirst,
307     _Sentinel1 __ilast,
308     _ForwardIterator __ofirst,
309     _EndPredicate __stop_moving,
310     _IterMove __iter_move) {
311   auto __idx = __ofirst;
312 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
313   try {
314 #endif
315     for (; __ifirst != __ilast && !__stop_moving(__idx); ++__idx, (void)++__ifirst) {
316       ::new (_VSTD::__voidify(*__idx)) _ValueType(__iter_move(__ifirst));
317     }
318 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
319   } catch (...) {
320     _VSTD::__destroy(__ofirst, __idx);
321     throw;
322   }
323 #endif
324 
325   return {_VSTD::move(__ifirst), _VSTD::move(__idx)};
326 }
327 
328 template <class _InputIterator, class _ForwardIterator>
uninitialized_move(_InputIterator __ifirst,_InputIterator __ilast,_ForwardIterator __ofirst)329 inline _LIBCPP_HIDE_FROM_ABI _ForwardIterator uninitialized_move(_InputIterator __ifirst, _InputIterator __ilast,
330                                                                  _ForwardIterator __ofirst) {
331   using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
332   auto __iter_move = [](auto&& __iter) -> decltype(auto) { return _VSTD::move(*__iter); };
333 
334   auto __result = std::__uninitialized_move<_ValueType>(
335       std::move(__ifirst), std::move(__ilast), std::move(__ofirst), __always_false(), __iter_move);
336   return _VSTD::move(__result.second);
337 }
338 
339 // uninitialized_move_n
340 
341 template <class _ValueType,
342           class _InputIterator,
343           class _Size,
344           class _ForwardIterator,
345           class _EndPredicate,
346           class _IterMove>
__uninitialized_move_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst,_EndPredicate __stop_moving,_IterMove __iter_move)347 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator> __uninitialized_move_n(
348     _InputIterator __ifirst, _Size __n, _ForwardIterator __ofirst, _EndPredicate __stop_moving, _IterMove __iter_move) {
349   auto __idx = __ofirst;
350 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
351   try {
352 #endif
353     for (; __n > 0 && !__stop_moving(__idx); ++__idx, (void)++__ifirst, --__n)
354       ::new (_VSTD::__voidify(*__idx)) _ValueType(__iter_move(__ifirst));
355 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
356   } catch (...) {
357     _VSTD::__destroy(__ofirst, __idx);
358     throw;
359   }
360 #endif
361 
362   return {_VSTD::move(__ifirst), _VSTD::move(__idx)};
363 }
364 
365 template <class _InputIterator, class _Size, class _ForwardIterator>
366 inline _LIBCPP_HIDE_FROM_ABI pair<_InputIterator, _ForwardIterator>
uninitialized_move_n(_InputIterator __ifirst,_Size __n,_ForwardIterator __ofirst)367 uninitialized_move_n(_InputIterator __ifirst, _Size __n, _ForwardIterator __ofirst) {
368   using _ValueType = typename iterator_traits<_ForwardIterator>::value_type;
369   auto __iter_move = [](auto&& __iter) -> decltype(auto) { return _VSTD::move(*__iter); };
370 
371   return std::__uninitialized_move_n<_ValueType>(
372       std::move(__ifirst), __n, std::move(__ofirst), __always_false(), __iter_move);
373 }
374 
375 // TODO: Rewrite this to iterate left to right and use reverse_iterators when calling
376 // Destroys every element in the range [first, last) FROM RIGHT TO LEFT using allocator
377 // destruction. If elements are themselves C-style arrays, they are recursively destroyed
378 // in the same manner.
379 //
380 // This function assumes that destructors do not throw, and that the allocator is bound to
381 // the correct type.
382 template<class _Alloc, class _BidirIter, class = __enable_if_t<
383     __has_bidirectional_iterator_category<_BidirIter>::value
384 >>
385 _LIBCPP_HIDE_FROM_ABI
__allocator_destroy_multidimensional(_Alloc & __alloc,_BidirIter __first,_BidirIter __last)386 constexpr void __allocator_destroy_multidimensional(_Alloc& __alloc, _BidirIter __first, _BidirIter __last) noexcept {
387     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
388     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _ValueType>,
389         "The allocator should already be rebound to the correct type");
390 
391     if (__first == __last)
392         return;
393 
394     if constexpr (is_array_v<_ValueType>) {
395         static_assert(!__libcpp_is_unbounded_array<_ValueType>::value,
396             "arrays of unbounded arrays don't exist, but if they did we would mess up here");
397 
398         using _Element = remove_extent_t<_ValueType>;
399         __allocator_traits_rebind_t<_Alloc, _Element> __elem_alloc(__alloc);
400         do {
401             --__last;
402             decltype(auto) __array = *__last;
403             std::__allocator_destroy_multidimensional(__elem_alloc, __array, __array + extent_v<_ValueType>);
404         } while (__last != __first);
405     } else {
406         do {
407             --__last;
408             allocator_traits<_Alloc>::destroy(__alloc, std::addressof(*__last));
409         } while (__last != __first);
410     }
411 }
412 
413 // Constructs the object at the given location using the allocator's construct method.
414 //
415 // If the object being constructed is an array, each element of the array is allocator-constructed,
416 // recursively. If an exception is thrown during the construction of an array, the initialized
417 // elements are destroyed in reverse order of initialization using allocator destruction.
418 //
419 // This function assumes that the allocator is bound to the correct type.
420 template<class _Alloc, class _Tp>
421 _LIBCPP_HIDE_FROM_ABI
__allocator_construct_at_multidimensional(_Alloc & __alloc,_Tp * __loc)422 constexpr void __allocator_construct_at_multidimensional(_Alloc& __alloc, _Tp* __loc) {
423     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _Tp>,
424         "The allocator should already be rebound to the correct type");
425 
426     if constexpr (is_array_v<_Tp>) {
427         using _Element = remove_extent_t<_Tp>;
428         __allocator_traits_rebind_t<_Alloc, _Element> __elem_alloc(__alloc);
429         size_t __i = 0;
430         _Tp& __array = *__loc;
431 
432         // If an exception is thrown, destroy what we have constructed so far in reverse order.
433         auto __guard = std::__make_exception_guard([&]() {
434           std::__allocator_destroy_multidimensional(__elem_alloc, __array, __array + __i);
435         });
436 
437         for (; __i != extent_v<_Tp>; ++__i) {
438             std::__allocator_construct_at_multidimensional(__elem_alloc, std::addressof(__array[__i]));
439         }
440         __guard.__complete();
441     } else {
442         allocator_traits<_Alloc>::construct(__alloc, __loc);
443     }
444 }
445 
446 // Constructs the object at the given location using the allocator's construct method, passing along
447 // the provided argument.
448 //
449 // If the object being constructed is an array, the argument is also assumed to be an array. Each
450 // each element of the array being constructed is allocator-constructed from the corresponding
451 // element of the argument array. If an exception is thrown during the construction of an array,
452 // the initialized elements are destroyed in reverse order of initialization using allocator
453 // destruction.
454 //
455 // This function assumes that the allocator is bound to the correct type.
456 template<class _Alloc, class _Tp, class _Arg>
457 _LIBCPP_HIDE_FROM_ABI
__allocator_construct_at_multidimensional(_Alloc & __alloc,_Tp * __loc,_Arg const & __arg)458 constexpr void __allocator_construct_at_multidimensional(_Alloc& __alloc, _Tp* __loc, _Arg const& __arg) {
459     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _Tp>,
460         "The allocator should already be rebound to the correct type");
461 
462     if constexpr (is_array_v<_Tp>) {
463         static_assert(is_array_v<_Arg>,
464             "Provided non-array initialization argument to __allocator_construct_at_multidimensional when "
465             "trying to construct an array.");
466 
467         using _Element = remove_extent_t<_Tp>;
468         __allocator_traits_rebind_t<_Alloc, _Element> __elem_alloc(__alloc);
469         size_t __i = 0;
470         _Tp& __array = *__loc;
471 
472         // If an exception is thrown, destroy what we have constructed so far in reverse order.
473         auto __guard = std::__make_exception_guard([&]() {
474           std::__allocator_destroy_multidimensional(__elem_alloc, __array, __array + __i);
475         });
476         for (; __i != extent_v<_Tp>; ++__i) {
477             std::__allocator_construct_at_multidimensional(__elem_alloc, std::addressof(__array[__i]), __arg[__i]);
478         }
479         __guard.__complete();
480     } else {
481         allocator_traits<_Alloc>::construct(__alloc, __loc, __arg);
482     }
483 }
484 
485 // Given a range starting at it and containing n elements, initializes each element in the
486 // range from left to right using the construct method of the allocator (rebound to the
487 // correct type).
488 //
489 // If an exception is thrown, the initialized elements are destroyed in reverse order of
490 // initialization using allocator_traits destruction. If the elements in the range are C-style
491 // arrays, they are initialized element-wise using allocator construction, and recursively so.
492 template<class _Alloc, class _BidirIter, class _Tp, class _Size = typename iterator_traits<_BidirIter>::difference_type>
493 _LIBCPP_HIDE_FROM_ABI constexpr void
__uninitialized_allocator_fill_n_multidimensional(_Alloc & __alloc,_BidirIter __it,_Size __n,_Tp const & __value)494 __uninitialized_allocator_fill_n_multidimensional(_Alloc& __alloc, _BidirIter __it, _Size __n, _Tp const& __value) {
495     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
496     __allocator_traits_rebind_t<_Alloc, _ValueType> __value_alloc(__alloc);
497     _BidirIter __begin = __it;
498 
499     // If an exception is thrown, destroy what we have constructed so far in reverse order.
500     auto __guard = std::__make_exception_guard([&]() { std::__allocator_destroy_multidimensional(__value_alloc, __begin, __it); });
501     for (; __n != 0; --__n, ++__it) {
502         std::__allocator_construct_at_multidimensional(__value_alloc, std::addressof(*__it), __value);
503     }
504     __guard.__complete();
505 }
506 
507 // Same as __uninitialized_allocator_fill_n_multidimensional, but doesn't pass any initialization argument
508 // to the allocator's construct method, which results in value initialization.
509 template <class _Alloc, class _BidirIter, class _Size = typename iterator_traits<_BidirIter>::difference_type>
510 _LIBCPP_HIDE_FROM_ABI constexpr void
__uninitialized_allocator_value_construct_n_multidimensional(_Alloc & __alloc,_BidirIter __it,_Size __n)511 __uninitialized_allocator_value_construct_n_multidimensional(_Alloc& __alloc, _BidirIter __it, _Size __n) {
512     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
513     __allocator_traits_rebind_t<_Alloc, _ValueType> __value_alloc(__alloc);
514     _BidirIter __begin = __it;
515 
516     // If an exception is thrown, destroy what we have constructed so far in reverse order.
517     auto __guard = std::__make_exception_guard([&]() { std::__allocator_destroy_multidimensional(__value_alloc, __begin, __it); });
518     for (; __n != 0; --__n, ++__it) {
519         std::__allocator_construct_at_multidimensional(__value_alloc, std::addressof(*__it));
520     }
521     __guard.__complete();
522 }
523 
524 #endif // _LIBCPP_STD_VER >= 17
525 
526 // Destroy all elements in [__first, __last) from left to right using allocator destruction.
527 template <class _Alloc, class _Iter, class _Sent>
528 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
__allocator_destroy(_Alloc & __alloc,_Iter __first,_Sent __last)529 __allocator_destroy(_Alloc& __alloc, _Iter __first, _Sent __last) {
530   for (; __first != __last; ++__first)
531      allocator_traits<_Alloc>::destroy(__alloc, std::__to_address(__first));
532 }
533 
534 template <class _Alloc, class _Iter>
535 class _AllocatorDestroyRangeReverse {
536 public:
537   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
_AllocatorDestroyRangeReverse(_Alloc & __alloc,_Iter & __first,_Iter & __last)538   _AllocatorDestroyRangeReverse(_Alloc& __alloc, _Iter& __first, _Iter& __last)
539       : __alloc_(__alloc), __first_(__first), __last_(__last) {}
540 
operator()541   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void operator()() const {
542     std::__allocator_destroy(__alloc_, std::reverse_iterator<_Iter>(__last_), std::reverse_iterator<_Iter>(__first_));
543   }
544 
545 private:
546   _Alloc& __alloc_;
547   _Iter& __first_;
548   _Iter& __last_;
549 };
550 
551 // Copy-construct [__first1, __last1) in [__first2, __first2 + N), where N is distance(__first1, __last1).
552 //
553 // The caller has to ensure that __first2 can hold at least N uninitialized elements. If an exception is thrown the
554 // already copied elements are destroyed in reverse order of their construction.
555 template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
556 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2
__uninitialized_allocator_copy_impl(_Alloc & __alloc,_Iter1 __first1,_Sent1 __last1,_Iter2 __first2)557 __uninitialized_allocator_copy_impl(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
558   auto __destruct_first = __first2;
559   auto __guard =
560       std::__make_exception_guard(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
561   while (__first1 != __last1) {
562     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), *__first1);
563     ++__first1;
564     ++__first2;
565   }
566   __guard.__complete();
567   return __first2;
568 }
569 
570 template <class _Alloc, class _Type>
571 struct __allocator_has_trivial_copy_construct : _Not<__has_construct<_Alloc, _Type*, const _Type&> > {};
572 
573 template <class _Type>
574 struct __allocator_has_trivial_copy_construct<allocator<_Type>, _Type> : true_type {};
575 
576 template <class _Alloc,
577           class _In,
578           class _RawTypeIn = __remove_const_t<_In>,
579           class _Out,
580           __enable_if_t<
581               // using _RawTypeIn because of the allocator<T const> extension
582               is_trivially_copy_constructible<_RawTypeIn>::value && is_trivially_copy_assignable<_RawTypeIn>::value &&
583               is_same<__remove_const_t<_In>, __remove_const_t<_Out> >::value &&
584               __allocator_has_trivial_copy_construct<_Alloc, _RawTypeIn>::value>* = nullptr>
585 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Out*
586 __uninitialized_allocator_copy_impl(_Alloc&, _In* __first1, _In* __last1, _Out* __first2) {
587   // TODO: Remove the const_cast once we drop support for std::allocator<T const>
588   if (__libcpp_is_constant_evaluated()) {
589     while (__first1 != __last1) {
590       std::__construct_at(std::__to_address(__first2), *__first1);
591       ++__first1;
592       ++__first2;
593     }
594     return __first2;
595   } else {
596     return std::copy(__first1, __last1, const_cast<_RawTypeIn*>(__first2));
597   }
598 }
599 
600 template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
601 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2 __uninitialized_allocator_copy(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
602     auto __unwrapped_range = std::__unwrap_range(__first1, __last1);
603     auto __result = std::__uninitialized_allocator_copy_impl(__alloc, __unwrapped_range.first, __unwrapped_range.second, std::__unwrap_iter(__first2));
604     return std::__rewrap_iter(__first2, __result);
605 }
606 
607 // Move-construct the elements [__first1, __last1) into [__first2, __first2 + N)
608 // if the move constructor is noexcept, where N is distance(__first1, __last1).
609 //
610 // Otherwise try to copy all elements. If an exception is thrown the already copied
611 // elements are destroyed in reverse order of their construction.
612 template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
613 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2 __uninitialized_allocator_move_if_noexcept(
614     _Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
615   static_assert(__is_cpp17_move_insertable<_Alloc>::value,
616                 "The specified type does not meet the requirements of Cpp17MoveInsertable");
617   auto __destruct_first = __first2;
618   auto __guard =
619       std::__make_exception_guard(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
620   while (__first1 != __last1) {
621 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
622     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), std::move_if_noexcept(*__first1));
623 #else
624     allocator_traits<_Alloc>::construct(__alloc, std::__to_address(__first2), std::move(*__first1));
625 #endif
626     ++__first1;
627     ++__first2;
628   }
629   __guard.__complete();
630   return __first2;
631 }
632 
633 template <class _Alloc, class _Type>
634 struct __allocator_has_trivial_move_construct : _Not<__has_construct<_Alloc, _Type*, _Type&&> > {};
635 
636 template <class _Type>
637 struct __allocator_has_trivial_move_construct<allocator<_Type>, _Type> : true_type {};
638 
639 #ifndef _LIBCPP_COMPILER_GCC
640 template <
641     class _Alloc,
642     class _Iter1,
643     class _Iter2,
644     class _Type = typename iterator_traits<_Iter1>::value_type,
645     class = __enable_if_t<is_trivially_move_constructible<_Type>::value && is_trivially_move_assignable<_Type>::value &&
646                           __allocator_has_trivial_move_construct<_Alloc, _Type>::value> >
647 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2
648 __uninitialized_allocator_move_if_noexcept(_Alloc&, _Iter1 __first1, _Iter1 __last1, _Iter2 __first2) {
649   if (__libcpp_is_constant_evaluated()) {
650     while (__first1 != __last1) {
651       std::__construct_at(std::__to_address(__first2), std::move(*__first1));
652       ++__first1;
653       ++__first2;
654     }
655     return __first2;
656   } else {
657     return std::move(__first1, __last1, __first2);
658   }
659 }
660 #endif // _LIBCPP_COMPILER_GCC
661 
662 _LIBCPP_END_NAMESPACE_STD
663 
664 #endif // _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
665