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_TYPE_TRAITS
11#define _LIBCPP_TYPE_TRAITS
12
13/*
14    type_traits synopsis
15
16namespace std
17{
18
19    // helper class:
20    template <class T, T v> struct integral_constant;
21    typedef integral_constant<bool, true>  true_type;   // C++11
22    typedef integral_constant<bool, false> false_type;  // C++11
23
24    template <bool B>                                   // C++14
25    using bool_constant = integral_constant<bool, B>;   // C++14
26    typedef bool_constant<true> true_type;              // C++14
27    typedef bool_constant<false> false_type;            // C++14
28
29    // helper traits
30    template <bool, class T = void> struct enable_if;
31    template <bool, class T, class F> struct conditional;
32
33    // Primary classification traits:
34    template <class T> struct is_void;
35    template <class T> struct is_null_pointer;  // C++14
36    template <class T> struct is_integral;
37    template <class T> struct is_floating_point;
38    template <class T> struct is_array;
39    template <class T> struct is_pointer;
40    template <class T> struct is_lvalue_reference;
41    template <class T> struct is_rvalue_reference;
42    template <class T> struct is_member_object_pointer;
43    template <class T> struct is_member_function_pointer;
44    template <class T> struct is_enum;
45    template <class T> struct is_union;
46    template <class T> struct is_class;
47    template <class T> struct is_function;
48
49    // Secondary classification traits:
50    template <class T> struct is_reference;
51    template <class T> struct is_arithmetic;
52    template <class T> struct is_fundamental;
53    template <class T> struct is_member_pointer;
54    template <class T> struct is_scoped_enum; // C++2b
55    template <class T> struct is_scalar;
56    template <class T> struct is_object;
57    template <class T> struct is_compound;
58
59    // Const-volatile properties and transformations:
60    template <class T> struct is_const;
61    template <class T> struct is_volatile;
62    template <class T> struct remove_const;
63    template <class T> struct remove_volatile;
64    template <class T> struct remove_cv;
65    template <class T> struct add_const;
66    template <class T> struct add_volatile;
67    template <class T> struct add_cv;
68
69    // Reference transformations:
70    template <class T> struct remove_reference;
71    template <class T> struct add_lvalue_reference;
72    template <class T> struct add_rvalue_reference;
73
74    // Pointer transformations:
75    template <class T> struct remove_pointer;
76    template <class T> struct add_pointer;
77
78    template<class T> struct type_identity;                     // C++20
79    template<class T>
80      using type_identity_t = typename type_identity<T>::type;  // C++20
81
82    // Integral properties:
83    template <class T> struct is_signed;
84    template <class T> struct is_unsigned;
85    template <class T> struct make_signed;
86    template <class T> struct make_unsigned;
87
88    // Array properties and transformations:
89    template <class T> struct rank;
90    template <class T, unsigned I = 0> struct extent;
91    template <class T> struct remove_extent;
92    template <class T> struct remove_all_extents;
93
94    template <class T> struct is_bounded_array;                 // C++20
95    template <class T> struct is_unbounded_array;               // C++20
96
97    // Member introspection:
98    template <class T> struct is_pod;
99    template <class T> struct is_trivial;
100    template <class T> struct is_trivially_copyable;
101    template <class T> struct is_standard_layout;
102    template <class T> struct is_literal_type; // Deprecated in C++17; removed in C++20
103    template <class T> struct is_empty;
104    template <class T> struct is_polymorphic;
105    template <class T> struct is_abstract;
106    template <class T> struct is_final; // C++14
107    template <class T> struct is_aggregate; // C++17
108
109    template <class T, class... Args> struct is_constructible;
110    template <class T>                struct is_default_constructible;
111    template <class T>                struct is_copy_constructible;
112    template <class T>                struct is_move_constructible;
113    template <class T, class U>       struct is_assignable;
114    template <class T>                struct is_copy_assignable;
115    template <class T>                struct is_move_assignable;
116    template <class T, class U>       struct is_swappable_with;       // C++17
117    template <class T>                struct is_swappable;            // C++17
118    template <class T>                struct is_destructible;
119
120    template <class T, class... Args> struct is_trivially_constructible;
121    template <class T>                struct is_trivially_default_constructible;
122    template <class T>                struct is_trivially_copy_constructible;
123    template <class T>                struct is_trivially_move_constructible;
124    template <class T, class U>       struct is_trivially_assignable;
125    template <class T>                struct is_trivially_copy_assignable;
126    template <class T>                struct is_trivially_move_assignable;
127    template <class T>                struct is_trivially_destructible;
128
129    template <class T, class... Args> struct is_nothrow_constructible;
130    template <class T>                struct is_nothrow_default_constructible;
131    template <class T>                struct is_nothrow_copy_constructible;
132    template <class T>                struct is_nothrow_move_constructible;
133    template <class T, class U>       struct is_nothrow_assignable;
134    template <class T>                struct is_nothrow_copy_assignable;
135    template <class T>                struct is_nothrow_move_assignable;
136    template <class T, class U>       struct is_nothrow_swappable_with; // C++17
137    template <class T>                struct is_nothrow_swappable;      // C++17
138    template <class T>                struct is_nothrow_destructible;
139
140    template <class T> struct has_virtual_destructor;
141
142    template<class T> struct has_unique_object_representations;         // C++17
143
144    // Relationships between types:
145    template <class T, class U> struct is_same;
146    template <class Base, class Derived> struct is_base_of;
147
148    template <class From, class To> struct is_convertible;
149    template <typename From, typename To> struct is_nothrow_convertible;                  // C++20
150    template <typename From, typename To> inline constexpr bool is_nothrow_convertible_v; // C++20
151
152    template <class Fn, class... ArgTypes> struct is_invocable;
153    template <class R, class Fn, class... ArgTypes> struct is_invocable_r;
154
155    template <class Fn, class... ArgTypes> struct is_nothrow_invocable;
156    template <class R, class Fn, class... ArgTypes> struct is_nothrow_invocable_r;
157
158    // Alignment properties and transformations:
159    template <class T> struct alignment_of;
160    template <size_t Len, size_t Align = most_stringent_alignment_requirement>
161        struct aligned_storage;
162    template <size_t Len, class... Types> struct aligned_union;
163    template <class T> struct remove_cvref; // C++20
164
165    template <class T> struct decay;
166    template <class... T> struct common_type;
167    template <class T> struct underlying_type;
168    template <class> class result_of; // undefined; deprecated in C++17; removed in C++20
169    template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>; // deprecated in C++17; removed in C++20
170    template <class Fn, class... ArgTypes> struct invoke_result;  // C++17
171
172    // const-volatile modifications:
173    template <class T>
174      using remove_const_t    = typename remove_const<T>::type;  // C++14
175    template <class T>
176      using remove_volatile_t = typename remove_volatile<T>::type;  // C++14
177    template <class T>
178      using remove_cv_t       = typename remove_cv<T>::type;  // C++14
179    template <class T>
180      using add_const_t       = typename add_const<T>::type;  // C++14
181    template <class T>
182      using add_volatile_t    = typename add_volatile<T>::type;  // C++14
183    template <class T>
184      using add_cv_t          = typename add_cv<T>::type;  // C++14
185
186    // reference modifications:
187    template <class T>
188      using remove_reference_t     = typename remove_reference<T>::type;  // C++14
189    template <class T>
190      using add_lvalue_reference_t = typename add_lvalue_reference<T>::type;  // C++14
191    template <class T>
192      using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;  // C++14
193
194    // sign modifications:
195    template <class T>
196      using make_signed_t   = typename make_signed<T>::type;  // C++14
197    template <class T>
198      using make_unsigned_t = typename make_unsigned<T>::type;  // C++14
199
200    // array modifications:
201    template <class T>
202      using remove_extent_t      = typename remove_extent<T>::type;  // C++14
203    template <class T>
204      using remove_all_extents_t = typename remove_all_extents<T>::type;  // C++14
205
206    template <class T>
207      inline constexpr bool is_bounded_array_v
208        = is_bounded_array<T>::value;                                     // C++20
209      inline constexpr bool is_unbounded_array_v
210        = is_unbounded_array<T>::value;                                   // C++20
211
212    // pointer modifications:
213    template <class T>
214      using remove_pointer_t = typename remove_pointer<T>::type;  // C++14
215    template <class T>
216      using add_pointer_t    = typename add_pointer<T>::type;  // C++14
217
218    // other transformations:
219    template <size_t Len, size_t Align=default-alignment>
220      using aligned_storage_t = typename aligned_storage<Len,Align>::type;  // C++14
221    template <size_t Len, class... Types>
222      using aligned_union_t   = typename aligned_union<Len,Types...>::type;  // C++14
223    template <class T>
224      using remove_cvref_t    = typename remove_cvref<T>::type;  // C++20
225    template <class T>
226      using decay_t           = typename decay<T>::type;  // C++14
227    template <bool b, class T=void>
228      using enable_if_t       = typename enable_if<b,T>::type;  // C++14
229    template <bool b, class T, class F>
230      using conditional_t     = typename conditional<b,T,F>::type;  // C++14
231    template <class... T>
232      using common_type_t     = typename common_type<T...>::type;  // C++14
233    template <class T>
234      using underlying_type_t = typename underlying_type<T>::type;  // C++14
235    template <class T>
236      using result_of_t       = typename result_of<T>::type;  // C++14; deprecated in C++17; removed in C++20
237    template <class Fn, class... ArgTypes>
238      using invoke_result_t   = typename invoke_result<Fn, ArgTypes...>::type;  // C++17
239
240    template <class...>
241      using void_t = void;   // C++17
242
243      // See C++14 20.10.4.1, primary type categories
244      template <class T> inline constexpr bool is_void_v
245        = is_void<T>::value;                                             // C++17
246      template <class T> inline constexpr bool is_null_pointer_v
247        = is_null_pointer<T>::value;                                     // C++17
248      template <class T> inline constexpr bool is_integral_v
249        = is_integral<T>::value;                                         // C++17
250      template <class T> inline constexpr bool is_floating_point_v
251        = is_floating_point<T>::value;                                   // C++17
252      template <class T> inline constexpr bool is_array_v
253        = is_array<T>::value;                                            // C++17
254      template <class T> inline constexpr bool is_pointer_v
255        = is_pointer<T>::value;                                          // C++17
256      template <class T> inline constexpr bool is_lvalue_reference_v
257        = is_lvalue_reference<T>::value;                                 // C++17
258      template <class T> inline constexpr bool is_rvalue_reference_v
259        = is_rvalue_reference<T>::value;                                 // C++17
260      template <class T> inline constexpr bool is_member_object_pointer_v
261        = is_member_object_pointer<T>::value;                            // C++17
262      template <class T> inline constexpr bool is_member_function_pointer_v
263        = is_member_function_pointer<T>::value;                          // C++17
264      template <class T> inline constexpr bool is_enum_v
265        = is_enum<T>::value;                                             // C++17
266      template <class T> inline constexpr bool is_union_v
267        = is_union<T>::value;                                            // C++17
268      template <class T> inline constexpr bool is_class_v
269        = is_class<T>::value;                                            // C++17
270      template <class T> inline constexpr bool is_function_v
271        = is_function<T>::value;                                         // C++17
272
273      // See C++14 20.10.4.2, composite type categories
274      template <class T> inline constexpr bool is_reference_v
275        = is_reference<T>::value;                                        // C++17
276      template <class T> inline constexpr bool is_arithmetic_v
277        = is_arithmetic<T>::value;                                       // C++17
278      template <class T> inline constexpr bool is_fundamental_v
279        = is_fundamental<T>::value;                                      // C++17
280      template <class T> inline constexpr bool is_object_v
281        = is_object<T>::value;                                           // C++17
282      template <class T> inline constexpr bool is_scalar_v
283        = is_scalar<T>::value;                                           // C++17
284      template <class T> inline constexpr bool is_compound_v
285        = is_compound<T>::value;                                         // C++17
286      template <class T> inline constexpr bool is_member_pointer_v
287        = is_member_pointer<T>::value;                                   // C++17
288      template <class T> inline constexpr bool is_scoped_enum_v
289        = is_scoped_enum<T>::value;                                      // C++2b
290
291      // See C++14 20.10.4.3, type properties
292      template <class T> inline constexpr bool is_const_v
293        = is_const<T>::value;                                            // C++17
294      template <class T> inline constexpr bool is_volatile_v
295        = is_volatile<T>::value;                                         // C++17
296      template <class T> inline constexpr bool is_trivial_v
297        = is_trivial<T>::value;                                          // C++17
298      template <class T> inline constexpr bool is_trivially_copyable_v
299        = is_trivially_copyable<T>::value;                               // C++17
300      template <class T> inline constexpr bool is_standard_layout_v
301        = is_standard_layout<T>::value;                                  // C++17
302      template <class T> inline constexpr bool is_pod_v
303        = is_pod<T>::value;                                              // C++17
304      template <class T> inline constexpr bool is_literal_type_v
305        = is_literal_type<T>::value;                                     // C++17; deprecated in C++17; removed in C++20
306      template <class T> inline constexpr bool is_empty_v
307        = is_empty<T>::value;                                            // C++17
308      template <class T> inline constexpr bool is_polymorphic_v
309        = is_polymorphic<T>::value;                                      // C++17
310      template <class T> inline constexpr bool is_abstract_v
311        = is_abstract<T>::value;                                         // C++17
312      template <class T> inline constexpr bool is_final_v
313        = is_final<T>::value;                                            // C++17
314      template <class T> inline constexpr bool is_aggregate_v
315        = is_aggregate<T>::value;                                        // C++17
316      template <class T> inline constexpr bool is_signed_v
317        = is_signed<T>::value;                                           // C++17
318      template <class T> inline constexpr bool is_unsigned_v
319        = is_unsigned<T>::value;                                         // C++17
320      template <class T, class... Args> inline constexpr bool is_constructible_v
321        = is_constructible<T, Args...>::value;                           // C++17
322      template <class T> inline constexpr bool is_default_constructible_v
323        = is_default_constructible<T>::value;                            // C++17
324      template <class T> inline constexpr bool is_copy_constructible_v
325        = is_copy_constructible<T>::value;                               // C++17
326      template <class T> inline constexpr bool is_move_constructible_v
327        = is_move_constructible<T>::value;                               // C++17
328      template <class T, class U> inline constexpr bool is_assignable_v
329        = is_assignable<T, U>::value;                                    // C++17
330      template <class T> inline constexpr bool is_copy_assignable_v
331        = is_copy_assignable<T>::value;                                  // C++17
332      template <class T> inline constexpr bool is_move_assignable_v
333        = is_move_assignable<T>::value;                                  // C++17
334      template <class T, class U> inline constexpr bool is_swappable_with_v
335        = is_swappable_with<T, U>::value;                                // C++17
336      template <class T> inline constexpr bool is_swappable_v
337        = is_swappable<T>::value;                                        // C++17
338      template <class T> inline constexpr bool is_destructible_v
339        = is_destructible<T>::value;                                     // C++17
340      template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
341        = is_trivially_constructible<T, Args...>::value;                 // C++17
342      template <class T> inline constexpr bool is_trivially_default_constructible_v
343        = is_trivially_default_constructible<T>::value;                  // C++17
344      template <class T> inline constexpr bool is_trivially_copy_constructible_v
345        = is_trivially_copy_constructible<T>::value;                     // C++17
346      template <class T> inline constexpr bool is_trivially_move_constructible_v
347        = is_trivially_move_constructible<T>::value;                     // C++17
348      template <class T, class U> inline constexpr bool is_trivially_assignable_v
349        = is_trivially_assignable<T, U>::value;                          // C++17
350      template <class T> inline constexpr bool is_trivially_copy_assignable_v
351        = is_trivially_copy_assignable<T>::value;                        // C++17
352      template <class T> inline constexpr bool is_trivially_move_assignable_v
353        = is_trivially_move_assignable<T>::value;                        // C++17
354      template <class T> inline constexpr bool is_trivially_destructible_v
355        = is_trivially_destructible<T>::value;                           // C++17
356      template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
357        = is_nothrow_constructible<T, Args...>::value;                   // C++17
358      template <class T> inline constexpr bool is_nothrow_default_constructible_v
359        = is_nothrow_default_constructible<T>::value;                    // C++17
360      template <class T> inline constexpr bool is_nothrow_copy_constructible_v
361        = is_nothrow_copy_constructible<T>::value;                       // C++17
362      template <class T> inline constexpr bool is_nothrow_move_constructible_v
363        = is_nothrow_move_constructible<T>::value;                       // C++17
364      template <class T, class U> inline constexpr bool is_nothrow_assignable_v
365        = is_nothrow_assignable<T, U>::value;                            // C++17
366      template <class T> inline constexpr bool is_nothrow_copy_assignable_v
367        = is_nothrow_copy_assignable<T>::value;                          // C++17
368      template <class T> inline constexpr bool is_nothrow_move_assignable_v
369        = is_nothrow_move_assignable<T>::value;                          // C++17
370      template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
371        = is_nothrow_swappable_with<T, U>::value;                       // C++17
372      template <class T> inline constexpr bool is_nothrow_swappable_v
373        = is_nothrow_swappable<T>::value;                               // C++17
374      template <class T> inline constexpr bool is_nothrow_destructible_v
375        = is_nothrow_destructible<T>::value;                             // C++17
376      template <class T> inline constexpr bool has_virtual_destructor_v
377        = has_virtual_destructor<T>::value;                              // C++17
378      template<class T> inline constexpr bool has_unique_object_representations_v // C++17
379        = has_unique_object_representations<T>::value;
380
381      // See C++14 20.10.5, type property queries
382      template <class T> inline constexpr size_t alignment_of_v
383        = alignment_of<T>::value;                                        // C++17
384      template <class T> inline constexpr size_t rank_v
385        = rank<T>::value;                                                // C++17
386      template <class T, unsigned I = 0> inline constexpr size_t extent_v
387        = extent<T, I>::value;                                           // C++17
388
389      // See C++14 20.10.6, type relations
390      template <class T, class U> inline constexpr bool is_same_v
391        = is_same<T, U>::value;                                          // C++17
392      template <class Base, class Derived> inline constexpr bool is_base_of_v
393        = is_base_of<Base, Derived>::value;                              // C++17
394      template <class From, class To> inline constexpr bool is_convertible_v
395        = is_convertible<From, To>::value;                               // C++17
396      template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
397        = is_invocable<Fn, ArgTypes...>::value;                          // C++17
398      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
399        = is_invocable_r<R, Fn, ArgTypes...>::value;                     // C++17
400      template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
401        = is_nothrow_invocable<Fn, ArgTypes...>::value;                  // C++17
402      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
403        = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value;             // C++17
404
405      // [meta.logical], logical operator traits:
406      template<class... B> struct conjunction;                           // C++17
407      template<class... B>
408        inline constexpr bool conjunction_v = conjunction<B...>::value;  // C++17
409      template<class... B> struct disjunction;                           // C++17
410      template<class... B>
411        inline constexpr bool disjunction_v = disjunction<B...>::value;  // C++17
412      template<class B> struct negation;                                 // C++17
413      template<class B>
414        inline constexpr bool negation_v = negation<B>::value;           // C++17
415
416}
417
418*/
419#include <__assert> // all public C++ headers provide the assertion handler
420#include <__config>
421#include <__functional/invoke.h>
422#include <__type_traits/add_const.h>
423#include <__type_traits/add_cv.h>
424#include <__type_traits/add_lvalue_reference.h>
425#include <__type_traits/add_pointer.h>
426#include <__type_traits/add_rvalue_reference.h>
427#include <__type_traits/add_volatile.h>
428#include <__type_traits/alignment_of.h>
429#include <__type_traits/apply_cv.h>
430#include <__type_traits/conditional.h>
431#include <__type_traits/conjunction.h>
432#include <__type_traits/decay.h>
433#include <__type_traits/disjunction.h>
434#include <__type_traits/enable_if.h>
435#include <__type_traits/extent.h>
436#include <__type_traits/has_unique_object_representation.h>
437#include <__type_traits/has_virtual_destructor.h>
438#include <__type_traits/integral_constant.h>
439#include <__type_traits/is_abstract.h>
440#include <__type_traits/is_aggregate.h>
441#include <__type_traits/is_arithmetic.h>
442#include <__type_traits/is_array.h>
443#include <__type_traits/is_assignable.h>
444#include <__type_traits/is_base_of.h>
445#include <__type_traits/is_bounded_array.h>
446#include <__type_traits/is_callable.h>
447#include <__type_traits/is_class.h>
448#include <__type_traits/is_compound.h>
449#include <__type_traits/is_const.h>
450#include <__type_traits/is_constant_evaluated.h>
451#include <__type_traits/is_constructible.h>
452#include <__type_traits/is_convertible.h>
453#include <__type_traits/is_copy_assignable.h>
454#include <__type_traits/is_copy_constructible.h>
455#include <__type_traits/is_default_constructible.h>
456#include <__type_traits/is_destructible.h>
457#include <__type_traits/is_empty.h>
458#include <__type_traits/is_enum.h>
459#include <__type_traits/is_final.h>
460#include <__type_traits/is_floating_point.h>
461#include <__type_traits/is_function.h>
462#include <__type_traits/is_fundamental.h>
463#include <__type_traits/is_integral.h>
464#include <__type_traits/is_literal_type.h>
465#include <__type_traits/is_member_function_pointer.h>
466#include <__type_traits/is_member_object_pointer.h>
467#include <__type_traits/is_member_pointer.h>
468#include <__type_traits/is_move_assignable.h>
469#include <__type_traits/is_move_constructible.h>
470#include <__type_traits/is_nothrow_assignable.h>
471#include <__type_traits/is_nothrow_constructible.h>
472#include <__type_traits/is_nothrow_copy_assignable.h>
473#include <__type_traits/is_nothrow_copy_constructible.h>
474#include <__type_traits/is_nothrow_default_constructible.h>
475#include <__type_traits/is_nothrow_destructible.h>
476#include <__type_traits/is_nothrow_move_assignable.h>
477#include <__type_traits/is_nothrow_move_constructible.h>
478#include <__type_traits/is_null_pointer.h>
479#include <__type_traits/is_object.h>
480#include <__type_traits/is_pod.h>
481#include <__type_traits/is_pointer.h>
482#include <__type_traits/is_polymorphic.h>
483#include <__type_traits/is_reference.h>
484#include <__type_traits/is_reference_wrapper.h>
485#include <__type_traits/is_referenceable.h>
486#include <__type_traits/is_same.h>
487#include <__type_traits/is_scalar.h>
488#include <__type_traits/is_scoped_enum.h>
489#include <__type_traits/is_signed.h>
490#include <__type_traits/is_standard_layout.h>
491#include <__type_traits/is_trivial.h>
492#include <__type_traits/is_trivially_assignable.h>
493#include <__type_traits/is_trivially_constructible.h>
494#include <__type_traits/is_trivially_copy_assignable.h>
495#include <__type_traits/is_trivially_copy_constructible.h>
496#include <__type_traits/is_trivially_copyable.h>
497#include <__type_traits/is_trivially_default_constructible.h>
498#include <__type_traits/is_trivially_destructible.h>
499#include <__type_traits/is_trivially_move_assignable.h>
500#include <__type_traits/is_trivially_move_constructible.h>
501#include <__type_traits/is_unbounded_array.h>
502#include <__type_traits/is_union.h>
503#include <__type_traits/is_unsigned.h>
504#include <__type_traits/is_void.h>
505#include <__type_traits/is_volatile.h>
506#include <__type_traits/negation.h>
507#include <__type_traits/rank.h>
508#include <__type_traits/remove_all_extents.h>
509#include <__type_traits/remove_const.h>
510#include <__type_traits/remove_cv.h>
511#include <__type_traits/remove_extent.h>
512#include <__type_traits/remove_pointer.h>
513#include <__type_traits/remove_reference.h>
514#include <__type_traits/remove_volatile.h>
515#include <__type_traits/type_identity.h>
516#include <__type_traits/underlying_type.h>
517#include <__type_traits/void_t.h>
518#include <__utility/declval.h>
519#include <cstddef>
520#include <cstdint>
521#include <version>
522
523#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
524#  pragma GCC system_header
525#endif
526
527_LIBCPP_BEGIN_NAMESPACE_STD
528
529template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
530template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
531
532template <template <class...> class _Func, class ..._Args>
533struct _Lazy : _Func<_Args...> {};
534
535// Member detector base
536
537template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
538true_type __sfinae_test_impl(int);
539template <template <class...> class, class ...>
540false_type __sfinae_test_impl(...);
541
542template <template <class ...> class _Templ, class ..._Args>
543using _IsValidExpansion _LIBCPP_NODEBUG = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
544
545template <class _Tp, bool>
546struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
547
548// is_same
549
550template <class _Tp>
551using __test_for_primary_template = __enable_if_t<
552    _IsSame<_Tp, typename _Tp::__primary_template>::value
553  >;
554template <class _Tp>
555using __is_primary_template = _IsValidExpansion<
556    __test_for_primary_template, _Tp
557  >;
558
559// is_integral
560
561// [basic.fundamental] defines five standard signed integer types;
562// __int128_t is an extended signed integer type.
563// The signed and unsigned integer types, plus bool and the
564// five types with "char" in their name, compose the "integral" types.
565
566template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
567template <> struct __libcpp_is_signed_integer<signed char>      : public true_type {};
568template <> struct __libcpp_is_signed_integer<signed short>     : public true_type {};
569template <> struct __libcpp_is_signed_integer<signed int>       : public true_type {};
570template <> struct __libcpp_is_signed_integer<signed long>      : public true_type {};
571template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
572#ifndef _LIBCPP_HAS_NO_INT128
573template <> struct __libcpp_is_signed_integer<__int128_t>       : public true_type {};
574#endif
575
576template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
577template <> struct __libcpp_is_unsigned_integer<unsigned char>      : public true_type {};
578template <> struct __libcpp_is_unsigned_integer<unsigned short>     : public true_type {};
579template <> struct __libcpp_is_unsigned_integer<unsigned int>       : public true_type {};
580template <> struct __libcpp_is_unsigned_integer<unsigned long>      : public true_type {};
581template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
582#ifndef _LIBCPP_HAS_NO_INT128
583template <> struct __libcpp_is_unsigned_integer<__uint128_t>        : public true_type {};
584#endif
585
586template <class _Tp>
587struct __unconstref {
588    typedef _LIBCPP_NODEBUG typename remove_const<typename remove_reference<_Tp>::type>::type type;
589};
590
591template <class _Tp>
592using __uncvref_t _LIBCPP_NODEBUG = typename remove_cv<typename remove_reference<_Tp>::type>::type;
593
594// __is_same_uncvref
595
596template <class _Tp, class _Up>
597struct __is_same_uncvref : _IsSame<__uncvref_t<_Tp>, __uncvref_t<_Up> > {};
598
599#if _LIBCPP_STD_VER > 17
600// remove_cvref - same as __uncvref
601template <class _Tp>
602struct remove_cvref {
603    using type _LIBCPP_NODEBUG = __uncvref_t<_Tp>;
604};
605
606template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
607#endif
608
609// is_nothrow_convertible
610
611#if _LIBCPP_STD_VER > 17
612
613template <typename _Tp>
614static void __test_noexcept(_Tp) noexcept;
615
616template<typename _Fm, typename _To>
617static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
618__is_nothrow_convertible_test();
619
620template <typename _Fm, typename _To>
621struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
622{ };
623
624template <typename _Fm, typename _To>
625struct is_nothrow_convertible : _Or<
626    _And<is_void<_To>, is_void<_Fm>>,
627    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
628>::type { };
629
630template <typename _Fm, typename _To>
631inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
632
633#endif // _LIBCPP_STD_VER > 17
634
635// aligned_storage
636
637template <class _Hp, class _Tp>
638struct __type_list
639{
640    typedef _Hp _Head;
641    typedef _Tp _Tail;
642};
643
644template <class _Tp>
645struct __align_type
646{
647    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
648    typedef _Tp type;
649};
650
651struct __struct_double {long double __lx;};
652struct __struct_double4 {double __lx[4];};
653
654typedef
655    __type_list<__align_type<unsigned char>,
656    __type_list<__align_type<unsigned short>,
657    __type_list<__align_type<unsigned int>,
658    __type_list<__align_type<unsigned long>,
659    __type_list<__align_type<unsigned long long>,
660    __type_list<__align_type<double>,
661    __type_list<__align_type<long double>,
662    __type_list<__align_type<__struct_double>,
663    __type_list<__align_type<__struct_double4>,
664    __type_list<__align_type<int*>,
665    __nat
666    > > > > > > > > > > __all_types;
667
668template <size_t _Align>
669struct _ALIGNAS(_Align) __fallback_overaligned {};
670
671template <class _TL, size_t _Align> struct __find_pod;
672
673template <class _Hp, size_t _Align>
674struct __find_pod<__type_list<_Hp, __nat>, _Align>
675{
676    typedef typename conditional<
677                             _Align == _Hp::value,
678                             typename _Hp::type,
679                             __fallback_overaligned<_Align>
680                         >::type type;
681};
682
683template <class _Hp, class _Tp, size_t _Align>
684struct __find_pod<__type_list<_Hp, _Tp>, _Align>
685{
686    typedef typename conditional<
687                             _Align == _Hp::value,
688                             typename _Hp::type,
689                             typename __find_pod<_Tp, _Align>::type
690                         >::type type;
691};
692
693template <class _TL, size_t _Len> struct __find_max_align;
694
695template <class _Hp, size_t _Len>
696struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
697
698template <size_t _Len, size_t _A1, size_t _A2>
699struct __select_align
700{
701private:
702    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
703    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
704public:
705    static const size_t value = _Len < __max ? __min : __max;
706};
707
708template <class _Hp, class _Tp, size_t _Len>
709struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
710    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
711
712template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
713struct _LIBCPP_TEMPLATE_VIS aligned_storage
714{
715    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
716    union type
717    {
718        _Aligner __align;
719        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
720    };
721};
722
723#if _LIBCPP_STD_VER > 11
724template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
725    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
726#endif
727
728#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
729template <size_t _Len>\
730struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
731{\
732    struct _ALIGNAS(n) type\
733    {\
734        unsigned char __lx[(_Len + n - 1)/n * n];\
735    };\
736}
737
738_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
739_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
740_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
741_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
742_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
743_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
744_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
745_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
746_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
747_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
748_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
749_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
750_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
751_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
752// PE/COFF does not support alignment beyond 8192 (=0x2000)
753#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
754_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
755#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
756
757#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
758
759
760// aligned_union
761
762template <size_t _I0, size_t ..._In>
763struct __static_max;
764
765template <size_t _I0>
766struct __static_max<_I0>
767{
768    static const size_t value = _I0;
769};
770
771template <size_t _I0, size_t _I1, size_t ..._In>
772struct __static_max<_I0, _I1, _In...>
773{
774    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
775                                             __static_max<_I1, _In...>::value;
776};
777
778template <size_t _Len, class _Type0, class ..._Types>
779struct aligned_union
780{
781    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
782                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
783    static const size_t __len = __static_max<_Len, sizeof(_Type0),
784                                             sizeof(_Types)...>::value;
785    typedef typename aligned_storage<__len, alignment_value>::type type;
786};
787
788#if _LIBCPP_STD_VER > 11
789template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
790#endif
791
792template <class _Tp>
793struct __numeric_type
794{
795   static void __test(...);
796   static float __test(float);
797   static double __test(char);
798   static double __test(int);
799   static double __test(unsigned);
800   static double __test(long);
801   static double __test(unsigned long);
802   static double __test(long long);
803   static double __test(unsigned long long);
804   static double __test(double);
805   static long double __test(long double);
806
807   typedef decltype(__test(declval<_Tp>())) type;
808   static const bool value = _IsNotSame<type, void>::value;
809};
810
811template <>
812struct __numeric_type<void>
813{
814   static const bool value = true;
815};
816
817// __promote
818
819template <class _A1, class _A2 = void, class _A3 = void,
820          bool = __numeric_type<_A1>::value &&
821                 __numeric_type<_A2>::value &&
822                 __numeric_type<_A3>::value>
823class __promote_imp
824{
825public:
826    static const bool value = false;
827};
828
829template <class _A1, class _A2, class _A3>
830class __promote_imp<_A1, _A2, _A3, true>
831{
832private:
833    typedef typename __promote_imp<_A1>::type __type1;
834    typedef typename __promote_imp<_A2>::type __type2;
835    typedef typename __promote_imp<_A3>::type __type3;
836public:
837    typedef decltype(__type1() + __type2() + __type3()) type;
838    static const bool value = true;
839};
840
841template <class _A1, class _A2>
842class __promote_imp<_A1, _A2, void, true>
843{
844private:
845    typedef typename __promote_imp<_A1>::type __type1;
846    typedef typename __promote_imp<_A2>::type __type2;
847public:
848    typedef decltype(__type1() + __type2()) type;
849    static const bool value = true;
850};
851
852template <class _A1>
853class __promote_imp<_A1, void, void, true>
854{
855public:
856    typedef typename __numeric_type<_A1>::type type;
857    static const bool value = true;
858};
859
860template <class _A1, class _A2 = void, class _A3 = void>
861class __promote : public __promote_imp<_A1, _A2, _A3> {};
862
863// make_signed / make_unsigned
864
865typedef
866    __type_list<signed char,
867    __type_list<signed short,
868    __type_list<signed int,
869    __type_list<signed long,
870    __type_list<signed long long,
871#ifndef _LIBCPP_HAS_NO_INT128
872    __type_list<__int128_t,
873#endif
874    __nat
875#ifndef _LIBCPP_HAS_NO_INT128
876    >
877#endif
878    > > > > > __signed_types;
879
880typedef
881    __type_list<unsigned char,
882    __type_list<unsigned short,
883    __type_list<unsigned int,
884    __type_list<unsigned long,
885    __type_list<unsigned long long,
886#ifndef _LIBCPP_HAS_NO_INT128
887    __type_list<__uint128_t,
888#endif
889    __nat
890#ifndef _LIBCPP_HAS_NO_INT128
891    >
892#endif
893    > > > > > __unsigned_types;
894
895template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
896
897template <class _Hp, class _Tp, size_t _Size>
898struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
899{
900    typedef _LIBCPP_NODEBUG _Hp type;
901};
902
903template <class _Hp, class _Tp, size_t _Size>
904struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
905{
906    typedef _LIBCPP_NODEBUG typename __find_first<_Tp, _Size>::type type;
907};
908
909template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
910struct __make_signed {};
911
912template <class _Tp>
913struct __make_signed<_Tp, true>
914{
915    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
916};
917
918template <> struct __make_signed<bool,               true> {};
919template <> struct __make_signed<  signed short,     true> {typedef short     type;};
920template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
921template <> struct __make_signed<  signed int,       true> {typedef int       type;};
922template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
923template <> struct __make_signed<  signed long,      true> {typedef long      type;};
924template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
925template <> struct __make_signed<  signed long long, true> {typedef long long type;};
926template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
927#ifndef _LIBCPP_HAS_NO_INT128
928template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
929template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
930#endif
931
932template <class _Tp>
933struct _LIBCPP_TEMPLATE_VIS make_signed
934{
935    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
936};
937
938#if _LIBCPP_STD_VER > 11
939template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
940#endif
941
942template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
943struct __make_unsigned {};
944
945template <class _Tp>
946struct __make_unsigned<_Tp, true>
947{
948    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
949};
950
951template <> struct __make_unsigned<bool,               true> {};
952template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
953template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
954template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
955template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
956template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
957template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
958template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
959template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
960#ifndef _LIBCPP_HAS_NO_INT128
961template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
962template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
963#endif
964
965template <class _Tp>
966struct _LIBCPP_TEMPLATE_VIS make_unsigned
967{
968    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
969};
970
971#if _LIBCPP_STD_VER > 11
972template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
973#endif
974
975#ifndef _LIBCPP_CXX03_LANG
976template <class _Tp>
977_LIBCPP_HIDE_FROM_ABI constexpr
978typename make_unsigned<_Tp>::type __to_unsigned_like(_Tp __x) noexcept {
979    return static_cast<typename make_unsigned<_Tp>::type>(__x);
980}
981#endif
982
983template <class _Tp, class _Up>
984using __copy_unsigned_t = __conditional_t<is_unsigned<_Tp>::value, typename make_unsigned<_Up>::type, _Up>;
985
986/// Helper to promote an integral to smallest 32, 64, or 128 bit representation.
987///
988/// The restriction is the same as the integral version of to_char.
989template <class _Tp>
990#if _LIBCPP_STD_VER > 17
991  requires (is_signed_v<_Tp> || is_unsigned_v<_Tp> || is_same_v<_Tp, char>)
992#endif
993using __make_32_64_or_128_bit_t =
994  __copy_unsigned_t<_Tp,
995    __conditional_t<sizeof(_Tp) <= sizeof(int32_t),    int32_t,
996    __conditional_t<sizeof(_Tp) <= sizeof(int64_t),    int64_t,
997#ifndef _LIBCPP_HAS_NO_INT128
998    __conditional_t<sizeof(_Tp) <= sizeof(__int128_t), __int128_t,
999    /* else */                                         void>
1000#else
1001    /* else */                                         void
1002#endif
1003    > >
1004  >;
1005
1006#if _LIBCPP_STD_VER > 17
1007// Let COND_RES(X, Y) be:
1008template <class _Tp, class _Up>
1009using __cond_type = decltype(false ? declval<_Tp>() : declval<_Up>());
1010
1011template <class _Tp, class _Up, class = void>
1012struct __common_type3 {};
1013
1014// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
1015template <class _Tp, class _Up>
1016struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
1017{
1018    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
1019};
1020
1021template <class _Tp, class _Up, class = void>
1022struct __common_type2_imp : __common_type3<_Tp, _Up> {};
1023#else
1024template <class _Tp, class _Up, class = void>
1025struct __common_type2_imp {};
1026#endif
1027
1028// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
1029template <class _Tp, class _Up>
1030struct __common_type2_imp<_Tp, _Up,
1031                          typename __void_t<decltype(
1032                                            true ? declval<_Tp>() : declval<_Up>()
1033                                            )>::type>
1034{
1035  typedef _LIBCPP_NODEBUG typename decay<decltype(
1036                         true ? declval<_Tp>() : declval<_Up>()
1037                         )>::type type;
1038};
1039
1040template <class, class = void>
1041struct __common_type_impl {};
1042
1043// Clang provides variadic templates in C++03 as an extension.
1044#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
1045# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
1046template <class... _Tp>
1047struct __common_types;
1048template <class... _Tp>
1049struct _LIBCPP_TEMPLATE_VIS common_type;
1050#else
1051# define _LIBCPP_OPTIONAL_PACK(...)
1052struct __no_arg;
1053template <class _Tp, class _Up, class = __no_arg>
1054struct __common_types;
1055template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
1056          class _Unused = __no_arg>
1057struct common_type {
1058  static_assert(sizeof(_Unused) == 0,
1059                "common_type accepts at most 3 arguments in C++03");
1060};
1061#endif // _LIBCPP_CXX03_LANG
1062
1063template <class _Tp, class _Up>
1064struct __common_type_impl<
1065    __common_types<_Tp, _Up>,
1066    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
1067{
1068  typedef typename common_type<_Tp, _Up>::type type;
1069};
1070
1071template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
1072struct __common_type_impl<
1073    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
1074    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
1075    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
1076                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
1077};
1078
1079// bullet 1 - sizeof...(Tp) == 0
1080
1081template <>
1082struct _LIBCPP_TEMPLATE_VIS common_type<> {};
1083
1084// bullet 2 - sizeof...(Tp) == 1
1085
1086template <class _Tp>
1087struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
1088    : public common_type<_Tp, _Tp> {};
1089
1090// bullet 3 - sizeof...(Tp) == 2
1091
1092// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
1093template <class _Tp, class _Up>
1094struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
1095    : conditional<
1096        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
1097        __common_type2_imp<_Tp, _Up>,
1098        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
1099    >::type
1100{};
1101
1102// bullet 4 - sizeof...(Tp) > 2
1103
1104template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
1105struct _LIBCPP_TEMPLATE_VIS
1106    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
1107    : __common_type_impl<
1108          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
1109
1110#undef _LIBCPP_OPTIONAL_PACK
1111
1112#if _LIBCPP_STD_VER > 11
1113template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
1114#endif
1115
1116// Let COPYCV(FROM, TO) be an alias for type TO with the addition of FROM's
1117// top-level cv-qualifiers.
1118template <class _From, class _To>
1119struct __copy_cv
1120{
1121    using type = _To;
1122};
1123
1124template <class _From, class _To>
1125struct __copy_cv<const _From, _To>
1126{
1127    using type = typename add_const<_To>::type;
1128};
1129
1130template <class _From, class _To>
1131struct __copy_cv<volatile _From, _To>
1132{
1133    using type = typename add_volatile<_To>::type;
1134};
1135
1136template <class _From, class _To>
1137struct __copy_cv<const volatile _From, _To>
1138{
1139    using type = typename add_cv<_To>::type;
1140};
1141
1142template <class _From, class _To>
1143using __copy_cv_t = typename __copy_cv<_From, _To>::type;
1144
1145template <class _From, class _To>
1146struct __copy_cvref
1147{
1148    using type = __copy_cv_t<_From, _To>;
1149};
1150
1151template <class _From, class _To>
1152struct __copy_cvref<_From&, _To>
1153{
1154    using type = typename add_lvalue_reference<__copy_cv_t<_From, _To> >::type;
1155};
1156
1157template <class _From, class _To>
1158struct __copy_cvref<_From&&, _To>
1159{
1160    using type = typename add_rvalue_reference<__copy_cv_t<_From, _To> >::type;
1161};
1162
1163template <class _From, class _To>
1164using __copy_cvref_t = typename __copy_cvref<_From, _To>::type;
1165
1166
1167// common_reference
1168#if _LIBCPP_STD_VER > 17
1169// Let COND_RES(X, Y) be:
1170template <class _Xp, class _Yp>
1171using __cond_res =
1172    decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
1173
1174// Let `XREF(A)` denote a unary alias template `T` such that `T<U>` denotes the same type as `U`
1175// with the addition of `A`'s cv and reference qualifiers, for a non-reference cv-unqualified type
1176// `U`.
1177// [Note: `XREF(A)` is `__xref<A>::template __apply`]
1178template <class _Tp>
1179struct __xref {
1180  template<class _Up>
1181  using __apply = __copy_cvref_t<_Tp, _Up>;
1182};
1183
1184// Given types A and B, let X be remove_reference_t<A>, let Y be remove_reference_t<B>,
1185// and let COMMON-REF(A, B) be:
1186template<class _Ap, class _Bp, class _Xp = remove_reference_t<_Ap>, class _Yp = remove_reference_t<_Bp>>
1187struct __common_ref;
1188
1189template<class _Xp, class _Yp>
1190using __common_ref_t = typename __common_ref<_Xp, _Yp>::__type;
1191
1192template<class _Xp, class _Yp>
1193using __cv_cond_res = __cond_res<__copy_cv_t<_Xp, _Yp>&, __copy_cv_t<_Yp, _Xp>&>;
1194
1195
1196//    If A and B are both lvalue reference types, COMMON-REF(A, B) is
1197//    COND-RES(COPYCV(X, Y)&, COPYCV(Y, X)&) if that type exists and is a reference type.
1198template<class _Ap, class _Bp, class _Xp, class _Yp>
1199requires requires { typename __cv_cond_res<_Xp, _Yp>; } && is_reference_v<__cv_cond_res<_Xp, _Yp>>
1200struct __common_ref<_Ap&, _Bp&, _Xp, _Yp>
1201{
1202    using __type = __cv_cond_res<_Xp, _Yp>;
1203};
1204
1205//    Otherwise, let C be remove_reference_t<COMMON-REF(X&, Y&)>&&. ...
1206template <class _Xp, class _Yp>
1207using __common_ref_C = remove_reference_t<__common_ref_t<_Xp&, _Yp&>>&&;
1208
1209
1210//    .... If A and B are both rvalue reference types, C is well-formed, and
1211//    is_convertible_v<A, C> && is_convertible_v<B, C> is true, then COMMON-REF(A, B) is C.
1212template<class _Ap, class _Bp, class _Xp, class _Yp>
1213requires
1214  requires { typename __common_ref_C<_Xp, _Yp>; } &&
1215  is_convertible_v<_Ap&&, __common_ref_C<_Xp, _Yp>> &&
1216  is_convertible_v<_Bp&&, __common_ref_C<_Xp, _Yp>>
1217struct __common_ref<_Ap&&, _Bp&&, _Xp, _Yp>
1218{
1219    using __type = __common_ref_C<_Xp, _Yp>;
1220};
1221
1222//    Otherwise, let D be COMMON-REF(const X&, Y&). ...
1223template <class _Tp, class _Up>
1224using __common_ref_D = __common_ref_t<const _Tp&, _Up&>;
1225
1226//    ... If A is an rvalue reference and B is an lvalue reference and D is well-formed and
1227//    is_convertible_v<A, D> is true, then COMMON-REF(A, B) is D.
1228template<class _Ap, class _Bp, class _Xp, class _Yp>
1229requires requires { typename __common_ref_D<_Xp, _Yp>; } &&
1230         is_convertible_v<_Ap&&, __common_ref_D<_Xp, _Yp>>
1231struct __common_ref<_Ap&&, _Bp&, _Xp, _Yp>
1232{
1233    using __type = __common_ref_D<_Xp, _Yp>;
1234};
1235
1236//    Otherwise, if A is an lvalue reference and B is an rvalue reference, then
1237//    COMMON-REF(A, B) is COMMON-REF(B, A).
1238template<class _Ap, class _Bp, class _Xp, class _Yp>
1239struct __common_ref<_Ap&, _Bp&&, _Xp, _Yp> : __common_ref<_Bp&&, _Ap&> {};
1240
1241//    Otherwise, COMMON-REF(A, B) is ill-formed.
1242template<class _Ap, class _Bp, class _Xp, class _Yp>
1243struct __common_ref {};
1244
1245// Note C: For the common_reference trait applied to a parameter pack [...]
1246
1247template <class...>
1248struct common_reference;
1249
1250template <class... _Types>
1251using common_reference_t = typename common_reference<_Types...>::type;
1252
1253// bullet 1 - sizeof...(T) == 0
1254template<>
1255struct common_reference<> {};
1256
1257// bullet 2 - sizeof...(T) == 1
1258template <class _Tp>
1259struct common_reference<_Tp>
1260{
1261    using type = _Tp;
1262};
1263
1264// bullet 3 - sizeof...(T) == 2
1265template <class _Tp, class _Up> struct __common_reference_sub_bullet3;
1266template <class _Tp, class _Up> struct __common_reference_sub_bullet2 : __common_reference_sub_bullet3<_Tp, _Up> {};
1267template <class _Tp, class _Up> struct __common_reference_sub_bullet1 : __common_reference_sub_bullet2<_Tp, _Up> {};
1268
1269// sub-bullet 1 - If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, then
1270// the member typedef `type` denotes that type.
1271template <class _Tp, class _Up> struct common_reference<_Tp, _Up> : __common_reference_sub_bullet1<_Tp, _Up> {};
1272
1273template <class _Tp, class _Up>
1274requires is_reference_v<_Tp> && is_reference_v<_Up> && requires { typename __common_ref_t<_Tp, _Up>; }
1275struct __common_reference_sub_bullet1<_Tp, _Up>
1276{
1277    using type = __common_ref_t<_Tp, _Up>;
1278};
1279
1280// sub-bullet 2 - Otherwise, if basic_common_reference<remove_cvref_t<T1>, remove_cvref_t<T2>, XREF(T1), XREF(T2)>::type
1281// is well-formed, then the member typedef `type` denotes that type.
1282template <class, class, template <class> class, template <class> class> struct basic_common_reference {};
1283
1284template <class _Tp, class _Up>
1285using __basic_common_reference_t = typename basic_common_reference<
1286    remove_cvref_t<_Tp>, remove_cvref_t<_Up>,
1287    __xref<_Tp>::template __apply, __xref<_Up>::template __apply>::type;
1288
1289template <class _Tp, class _Up>
1290requires requires { typename __basic_common_reference_t<_Tp, _Up>; }
1291struct __common_reference_sub_bullet2<_Tp, _Up>
1292{
1293    using type = __basic_common_reference_t<_Tp, _Up>;
1294};
1295
1296// sub-bullet 3 - Otherwise, if COND-RES(T1, T2) is well-formed,
1297// then the member typedef `type` denotes that type.
1298template <class _Tp, class _Up>
1299requires requires { typename __cond_res<_Tp, _Up>; }
1300struct __common_reference_sub_bullet3<_Tp, _Up>
1301{
1302    using type = __cond_res<_Tp, _Up>;
1303};
1304
1305
1306// sub-bullet 4 & 5 - Otherwise, if common_type_t<T1, T2> is well-formed,
1307//                    then the member typedef `type` denotes that type.
1308//                  - Otherwise, there shall be no member `type`.
1309template <class _Tp, class _Up> struct __common_reference_sub_bullet3 : common_type<_Tp, _Up> {};
1310
1311// bullet 4 - If there is such a type `C`, the member typedef type shall denote the same type, if
1312//            any, as `common_reference_t<C, Rest...>`.
1313template <class _Tp, class _Up, class _Vp, class... _Rest>
1314requires requires { typename common_reference_t<_Tp, _Up>; }
1315struct common_reference<_Tp, _Up, _Vp, _Rest...>
1316    : common_reference<common_reference_t<_Tp, _Up>, _Vp, _Rest...>
1317{};
1318
1319// bullet 5 - Otherwise, there shall be no member `type`.
1320template <class...> struct common_reference {};
1321
1322#endif // _LIBCPP_STD_VER > 17
1323
1324#ifndef _LIBCPP_CXX03_LANG
1325// First of all, we can't implement this check in C++03 mode because the {}
1326// default initialization syntax isn't valid.
1327// Second, we implement the trait in a funny manner with two defaulted template
1328// arguments to workaround Clang's PR43454.
1329template <class _Tp>
1330void __test_implicit_default_constructible(_Tp);
1331
1332template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type>
1333struct __is_implicitly_default_constructible
1334    : false_type
1335{ };
1336
1337template <class _Tp>
1338struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true_type>
1339    : true_type
1340{ };
1341
1342template <class _Tp>
1343struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false_type>
1344    : false_type
1345{ };
1346#endif // !C++03
1347
1348// result_of
1349
1350#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
1351template <class _Callable> class _LIBCPP_DEPRECATED_IN_CXX17 result_of;
1352
1353template <class _Fp, class ..._Args>
1354class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
1355    : public __invoke_of<_Fp, _Args...>
1356{
1357};
1358
1359#if _LIBCPP_STD_VER > 11
1360template <class _Tp> using result_of_t _LIBCPP_DEPRECATED_IN_CXX17 = typename result_of<_Tp>::type;
1361#endif // _LIBCPP_STD_VER > 11
1362#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
1363
1364// __swappable
1365
1366template <class _Tp> struct __is_swappable;
1367template <class _Tp> struct __is_nothrow_swappable;
1368
1369
1370#ifndef _LIBCPP_CXX03_LANG
1371template <class _Tp>
1372using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
1373#else
1374template <class>
1375using __swap_result_t = void;
1376#endif
1377
1378template <class _Tp>
1379inline _LIBCPP_INLINE_VISIBILITY
1380_LIBCPP_CONSTEXPR_AFTER_CXX17 __swap_result_t<_Tp>
1381swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
1382                                    is_nothrow_move_assignable<_Tp>::value);
1383
1384template<class _Tp, size_t _Np>
1385inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1386typename enable_if<
1387    __is_swappable<_Tp>::value
1388>::type
1389swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
1390
1391namespace __detail
1392{
1393// ALL generic swap overloads MUST already have a declaration available at this point.
1394
1395template <class _Tp, class _Up = _Tp,
1396          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
1397struct __swappable_with
1398{
1399    template <class _LHS, class _RHS>
1400    static decltype(swap(declval<_LHS>(), declval<_RHS>()))
1401    __test_swap(int);
1402    template <class, class>
1403    static __nat __test_swap(long);
1404
1405    // Extra parens are needed for the C++03 definition of decltype.
1406    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
1407    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
1408
1409    static const bool value = _IsNotSame<__swap1, __nat>::value
1410                           && _IsNotSame<__swap2, __nat>::value;
1411};
1412
1413template <class _Tp, class _Up>
1414struct __swappable_with<_Tp, _Up,  false> : false_type {};
1415
1416template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
1417struct __nothrow_swappable_with {
1418  static const bool value =
1419#ifndef _LIBCPP_HAS_NO_NOEXCEPT
1420      noexcept(swap(declval<_Tp>(), declval<_Up>()))
1421  &&  noexcept(swap(declval<_Up>(), declval<_Tp>()));
1422#else
1423      false;
1424#endif
1425};
1426
1427template <class _Tp, class _Up>
1428struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
1429
1430} // namespace __detail
1431
1432template <class _Tp>
1433struct __is_swappable
1434    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
1435{
1436};
1437
1438template <class _Tp>
1439struct __is_nothrow_swappable
1440    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
1441{
1442};
1443
1444#if _LIBCPP_STD_VER > 14
1445
1446template <class _Tp, class _Up>
1447struct _LIBCPP_TEMPLATE_VIS is_swappable_with
1448    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
1449{
1450};
1451
1452template <class _Tp>
1453struct _LIBCPP_TEMPLATE_VIS is_swappable
1454    : public conditional<
1455        __is_referenceable<_Tp>::value,
1456        is_swappable_with<
1457            typename add_lvalue_reference<_Tp>::type,
1458            typename add_lvalue_reference<_Tp>::type>,
1459        false_type
1460    >::type
1461{
1462};
1463
1464template <class _Tp, class _Up>
1465struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
1466    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
1467{
1468};
1469
1470template <class _Tp>
1471struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
1472    : public conditional<
1473        __is_referenceable<_Tp>::value,
1474        is_nothrow_swappable_with<
1475            typename add_lvalue_reference<_Tp>::type,
1476            typename add_lvalue_reference<_Tp>::type>,
1477        false_type
1478    >::type
1479{
1480};
1481
1482template <class _Tp, class _Up>
1483inline constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
1484
1485template <class _Tp>
1486inline constexpr bool is_swappable_v = is_swappable<_Tp>::value;
1487
1488template <class _Tp, class _Up>
1489inline constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<_Tp, _Up>::value;
1490
1491template <class _Tp>
1492inline constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<_Tp>::value;
1493
1494#endif // _LIBCPP_STD_VER > 14
1495
1496template <class _Tp, bool = is_enum<_Tp>::value>
1497struct __sfinae_underlying_type
1498{
1499    typedef typename underlying_type<_Tp>::type type;
1500    typedef decltype(((type)1) + 0) __promoted_type;
1501};
1502
1503template <class _Tp>
1504struct __sfinae_underlying_type<_Tp, false> {};
1505
1506inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1507int __convert_to_integral(int __val) { return __val; }
1508
1509inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1510unsigned __convert_to_integral(unsigned __val) { return __val; }
1511
1512inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1513long __convert_to_integral(long __val) { return __val; }
1514
1515inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1516unsigned long __convert_to_integral(unsigned long __val) { return __val; }
1517
1518inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1519long long __convert_to_integral(long long __val) { return __val; }
1520
1521inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1522unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
1523
1524template<typename _Fp>
1525inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1526typename enable_if<is_floating_point<_Fp>::value, long long>::type
1527 __convert_to_integral(_Fp __val) { return __val; }
1528
1529#ifndef _LIBCPP_HAS_NO_INT128
1530inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1531__int128_t __convert_to_integral(__int128_t __val) { return __val; }
1532
1533inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1534__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
1535#endif
1536
1537template <class _Tp>
1538inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1539typename __sfinae_underlying_type<_Tp>::__promoted_type
1540__convert_to_integral(_Tp __val) { return __val; }
1541
1542// These traits are used in __tree and __hash_table
1543struct __extract_key_fail_tag {};
1544struct __extract_key_self_tag {};
1545struct __extract_key_first_tag {};
1546
1547template <class _ValTy, class _Key,
1548          class _RawValTy = typename __unconstref<_ValTy>::type>
1549struct __can_extract_key
1550    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
1551                  __extract_key_fail_tag>::type {};
1552
1553template <class _Pair, class _Key, class _First, class _Second>
1554struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
1555    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
1556                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
1557
1558// __can_extract_map_key uses true_type/false_type instead of the tags.
1559// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
1560// and _ValTy == _Key.
1561template <class _ValTy, class _Key, class _ContainerValueTy,
1562          class _RawValTy = typename __unconstref<_ValTy>::type>
1563struct __can_extract_map_key
1564    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
1565
1566// This specialization returns __extract_key_fail_tag for non-map containers
1567// because _Key == _ContainerValueTy
1568template <class _ValTy, class _Key, class _RawValTy>
1569struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
1570    : false_type {};
1571
1572template <class _CharT>
1573using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
1574
1575template<class _Tp>
1576using __make_const_lvalue_ref = const typename remove_reference<_Tp>::type&;
1577
1578template<bool _Const, class _Tp>
1579using __maybe_const = typename conditional<_Const, const _Tp, _Tp>::type;
1580
1581_LIBCPP_END_NAMESPACE_STD
1582
1583#endif // _LIBCPP_TYPE_TRAITS
1584