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 <__config>
420#include <cstddef>
421#include <version>
422
423#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
424#pragma GCC system_header
425#endif
426
427_LIBCPP_BEGIN_NAMESPACE_STD
428
429template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
430template <class _Tp> class _LIBCPP_TEMPLATE_VIS reference_wrapper;
431template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
432
433template <class _Tp, _Tp __v>
434struct _LIBCPP_TEMPLATE_VIS integral_constant
435{
436  static _LIBCPP_CONSTEXPR const _Tp      value = __v;
437  typedef _Tp               value_type;
438  typedef integral_constant type;
439  _LIBCPP_INLINE_VISIBILITY
440  _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT {return value;}
441#if _LIBCPP_STD_VER > 11
442  _LIBCPP_INLINE_VISIBILITY
443  constexpr value_type operator ()() const _NOEXCEPT {return value;}
444#endif
445};
446
447template <class _Tp, _Tp __v>
448_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
449
450#if _LIBCPP_STD_VER > 14
451template <bool __b>
452using bool_constant = integral_constant<bool, __b>;
453#define _LIBCPP_BOOL_CONSTANT(__b) bool_constant<(__b)>
454#else
455#define _LIBCPP_BOOL_CONSTANT(__b) integral_constant<bool,(__b)>
456#endif
457
458template <bool, class _Tp = void> struct _LIBCPP_TEMPLATE_VIS enable_if {};
459template <class _Tp> struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> {typedef _Tp type;};
460
461template <bool _Bp, class _Tp = void> using __enable_if_t _LIBCPP_NODEBUG = typename enable_if<_Bp, _Tp>::type;
462
463#if _LIBCPP_STD_VER > 11
464template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
465#endif
466
467typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
468typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
469
470template <bool _Val>
471using _BoolConstant _LIBCPP_NODEBUG = integral_constant<bool, _Val>;
472
473template <bool> struct _MetaBase;
474template <>
475struct _MetaBase<true> {
476  template <class _Tp, class _Up>
477  using _SelectImpl _LIBCPP_NODEBUG = _Tp;
478  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
479  using _SelectApplyImpl _LIBCPP_NODEBUG = _FirstFn<_Args...>;
480  template <class _First, class...>
481  using _FirstImpl _LIBCPP_NODEBUG = _First;
482  template <class, class _Second, class...>
483  using _SecondImpl _LIBCPP_NODEBUG = _Second;
484  template <class _Result, class _First, class ..._Rest>
485  using _OrImpl _LIBCPP_NODEBUG = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
486};
487
488template <>
489struct _MetaBase<false> {
490  template <class _Tp, class _Up>
491  using _SelectImpl _LIBCPP_NODEBUG = _Up;
492  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
493  using _SelectApplyImpl _LIBCPP_NODEBUG = _SecondFn<_Args...>;
494  template <class _Result, class ...>
495  using _OrImpl _LIBCPP_NODEBUG = _Result;
496};
497template <bool _Cond, class _IfRes, class _ElseRes>
498using _If _LIBCPP_NODEBUG = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
499template <class ..._Rest>
500using _Or _LIBCPP_NODEBUG = typename _MetaBase< sizeof...(_Rest) != 0 >::template _OrImpl<false_type, _Rest...>;
501template <class _Pred>
502struct _Not : _BoolConstant<!_Pred::value> {};
503template <class ..._Args>
504using _FirstType _LIBCPP_NODEBUG = typename _MetaBase<(sizeof...(_Args) >= 1)>::template _FirstImpl<_Args...>;
505template <class ..._Args>
506using _SecondType _LIBCPP_NODEBUG = typename _MetaBase<(sizeof...(_Args) >= 2)>::template _SecondImpl<_Args...>;
507
508template <class ...> using __expand_to_true = true_type;
509template <class ..._Pred>
510__expand_to_true<__enable_if_t<_Pred::value>...> __and_helper(int);
511template <class ...>
512false_type __and_helper(...);
513template <class ..._Pred>
514using _And _LIBCPP_NODEBUG = decltype(__and_helper<_Pred...>(0));
515
516template <template <class...> class _Func, class ..._Args>
517struct _Lazy : _Func<_Args...> {};
518
519// Member detector base
520
521template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
522true_type __sfinae_test_impl(int);
523template <template <class...> class, class ...>
524false_type __sfinae_test_impl(...);
525
526template <template <class ...> class _Templ, class ..._Args>
527using _IsValidExpansion _LIBCPP_NODEBUG = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
528
529template <class>
530struct __void_t { typedef void type; };
531
532template <class _Tp>
533struct __identity { typedef _Tp type; };
534
535template <class _Tp>
536using __identity_t _LIBCPP_NODEBUG = typename __identity<_Tp>::type;
537
538template <class _Tp, bool>
539struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
540
541
542template <bool _Bp, class _If, class _Then>
543    struct _LIBCPP_TEMPLATE_VIS conditional {typedef _If type;};
544template <class _If, class _Then>
545    struct _LIBCPP_TEMPLATE_VIS conditional<false, _If, _Then> {typedef _Then type;};
546
547#if _LIBCPP_STD_VER > 11
548template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
549#endif
550
551// is_same
552
553#if __has_keyword(__is_same)
554
555template <class _Tp, class _Up>
556struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
557
558#if _LIBCPP_STD_VER > 14
559template <class _Tp, class _Up>
560inline constexpr bool is_same_v = __is_same(_Tp, _Up);
561#endif
562
563#else
564
565template <class _Tp, class _Up> struct _LIBCPP_TEMPLATE_VIS is_same           : public false_type {};
566template <class _Tp>            struct _LIBCPP_TEMPLATE_VIS is_same<_Tp, _Tp> : public true_type {};
567
568#if _LIBCPP_STD_VER > 14
569template <class _Tp, class _Up>
570inline constexpr bool is_same_v = is_same<_Tp, _Up>::value;
571#endif
572
573#endif // __is_same
574
575template <class _Tp, class _Up>
576using _IsSame = _BoolConstant<
577#ifdef __clang__
578    __is_same(_Tp, _Up)
579#else
580    is_same<_Tp, _Up>::value
581#endif
582>;
583
584template <class _Tp, class _Up>
585using _IsNotSame = _BoolConstant<
586#ifdef __clang__
587    !__is_same(_Tp, _Up)
588#else
589    !is_same<_Tp, _Up>::value
590#endif
591>;
592
593
594template <class _Tp>
595using __test_for_primary_template = __enable_if_t<
596    _IsSame<_Tp, typename _Tp::__primary_template>::value
597  >;
598template <class _Tp>
599using __is_primary_template = _IsValidExpansion<
600    __test_for_primary_template, _Tp
601  >;
602
603struct __two {char __lx[2];};
604
605// helper class:
606
607// is_const
608
609#if __has_keyword(__is_const)
610
611template <class _Tp>
612struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
613
614#if _LIBCPP_STD_VER > 14
615template <class _Tp>
616inline constexpr bool is_const_v = __is_const(_Tp);
617#endif
618
619#else
620
621template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const            : public false_type {};
622template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {};
623
624#if _LIBCPP_STD_VER > 14
625template <class _Tp>
626inline constexpr bool is_const_v = is_const<_Tp>::value;
627#endif
628
629#endif // __has_keyword(__is_const)
630
631// is_volatile
632
633#if __has_keyword(__is_volatile)
634
635template <class _Tp>
636struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
637
638#if _LIBCPP_STD_VER > 14
639template <class _Tp>
640inline constexpr bool is_volatile_v = __is_volatile(_Tp);
641#endif
642
643#else
644
645template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile               : public false_type {};
646template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile<_Tp volatile> : public true_type {};
647
648#if _LIBCPP_STD_VER > 14
649template <class _Tp>
650inline constexpr bool is_volatile_v = is_volatile<_Tp>::value;
651#endif
652
653#endif // __has_keyword(__is_volatile)
654
655// remove_const
656
657#if __has_keyword(__remove_const)
658
659template <class _Tp>
660struct _LIBCPP_TEMPLATE_VIS remove_const {typedef __remove_const(_Tp) type;};
661
662#if _LIBCPP_STD_VER > 11
663template <class _Tp> using remove_const_t = __remove_const(_Tp);
664#endif
665
666#else
667
668template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const            {typedef _Tp type;};
669template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const<const _Tp> {typedef _Tp type;};
670#if _LIBCPP_STD_VER > 11
671template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
672#endif
673
674#endif // __has_keyword(__remove_const)
675
676// remove_volatile
677
678#if __has_keyword(__remove_volatile)
679
680template <class _Tp>
681struct _LIBCPP_TEMPLATE_VIS remove_volatile {typedef __remove_volatile(_Tp) type;};
682
683#if _LIBCPP_STD_VER > 11
684template <class _Tp> using remove_volatile_t = __remove_volatile(_Tp);
685#endif
686
687#else
688
689template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile               {typedef _Tp type;};
690template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile<volatile _Tp> {typedef _Tp type;};
691#if _LIBCPP_STD_VER > 11
692template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
693#endif
694
695#endif // __has_keyword(__remove_volatile)
696
697// remove_cv
698
699#if __has_keyword(__remove_cv)
700
701template <class _Tp>
702struct _LIBCPP_TEMPLATE_VIS remove_cv {typedef __remove_cv(_Tp) type;};
703
704#if _LIBCPP_STD_VER > 11
705template <class _Tp> using remove_cv_t = __remove_cv(_Tp);
706#endif
707
708#else
709
710template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_cv
711{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
712#if _LIBCPP_STD_VER > 11
713template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
714#endif
715
716#endif // __has_keyword(__remove_cv)
717
718// is_void
719
720#if __has_keyword(__is_void)
721
722template <class _Tp>
723struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
724
725#if _LIBCPP_STD_VER > 14
726template <class _Tp>
727inline constexpr bool is_void_v = __is_void(_Tp);
728#endif
729
730#else
731
732template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_void
733    : public is_same<typename remove_cv<_Tp>::type, void> {};
734
735#if _LIBCPP_STD_VER > 14
736template <class _Tp>
737inline constexpr bool is_void_v = is_void<_Tp>::value;
738#endif
739
740#endif // __has_keyword(__is_void)
741
742// __is_nullptr_t
743
744template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
745template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
746
747template <class _Tp> struct _LIBCPP_TEMPLATE_VIS __is_nullptr_t
748    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
749
750#if _LIBCPP_STD_VER > 11
751template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_null_pointer
752    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
753
754#if _LIBCPP_STD_VER > 14
755template <class _Tp>
756inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
757#endif
758#endif // _LIBCPP_STD_VER > 11
759
760// is_integral
761
762#if __has_keyword(__is_integral)
763
764template <class _Tp>
765struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
766
767#if _LIBCPP_STD_VER > 14
768template <class _Tp>
769inline constexpr bool is_integral_v = __is_integral(_Tp);
770#endif
771
772#else
773
774template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
775    : public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
776
777#if _LIBCPP_STD_VER > 14
778template <class _Tp>
779inline constexpr bool is_integral_v = is_integral<_Tp>::value;
780#endif
781
782#endif // __has_keyword(__is_integral)
783
784// [basic.fundamental] defines five standard signed integer types;
785// __int128_t is an extended signed integer type.
786// The signed and unsigned integer types, plus bool and the
787// five types with "char" in their name, compose the "integral" types.
788
789template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
790template <> struct __libcpp_is_signed_integer<signed char>      : public true_type {};
791template <> struct __libcpp_is_signed_integer<signed short>     : public true_type {};
792template <> struct __libcpp_is_signed_integer<signed int>       : public true_type {};
793template <> struct __libcpp_is_signed_integer<signed long>      : public true_type {};
794template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
795#ifndef _LIBCPP_HAS_NO_INT128
796template <> struct __libcpp_is_signed_integer<__int128_t>       : public true_type {};
797#endif
798
799template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
800template <> struct __libcpp_is_unsigned_integer<unsigned char>      : public true_type {};
801template <> struct __libcpp_is_unsigned_integer<unsigned short>     : public true_type {};
802template <> struct __libcpp_is_unsigned_integer<unsigned int>       : public true_type {};
803template <> struct __libcpp_is_unsigned_integer<unsigned long>      : public true_type {};
804template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
805#ifndef _LIBCPP_HAS_NO_INT128
806template <> struct __libcpp_is_unsigned_integer<__uint128_t>        : public true_type {};
807#endif
808
809// is_floating_point
810// <concepts> implements __libcpp_floating_point
811
812template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
813template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
814template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
815template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
816
817template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
818    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
819
820#if _LIBCPP_STD_VER > 14
821template <class _Tp>
822inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
823#endif
824
825// is_array
826
827#if __has_keyword(__is_array)
828
829template <class _Tp>
830struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
831
832#if _LIBCPP_STD_VER > 14
833template <class _Tp>
834inline constexpr bool is_array_v = __is_array(_Tp);
835#endif
836
837#else
838
839template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array
840    : public false_type {};
841template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]>
842    : public true_type {};
843template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]>
844    : public true_type {};
845
846#if _LIBCPP_STD_VER > 14
847template <class _Tp>
848inline constexpr bool is_array_v = is_array<_Tp>::value;
849#endif
850
851#endif // __has_keyword(__is_array)
852
853// is_pointer
854
855// Before AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
856#if __has_keyword(__is_pointer) &&                                             \
857    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205)
858
859template<class _Tp>
860struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
861
862#if _LIBCPP_STD_VER > 14
863template <class _Tp>
864inline constexpr bool is_pointer_v = __is_pointer(_Tp);
865#endif
866
867#else // __has_keyword(__is_pointer)
868
869template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
870template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
871
872template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
873#if defined(_LIBCPP_HAS_OBJC_ARC)
874template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
875template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
876template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
877template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
878#endif
879
880template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
881    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
882
883#if _LIBCPP_STD_VER > 14
884template <class _Tp>
885inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
886#endif
887
888#endif // __has_keyword(__is_pointer)
889
890// is_reference
891
892#if __has_keyword(__is_lvalue_reference) && \
893    __has_keyword(__is_rvalue_reference) && \
894    __has_keyword(__is_reference)
895
896template<class _Tp>
897struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
898
899template<class _Tp>
900struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
901
902template<class _Tp>
903struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
904
905#if _LIBCPP_STD_VER > 14
906template <class _Tp>
907inline constexpr bool is_reference_v = __is_reference(_Tp);
908template <class _Tp>
909inline constexpr bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
910template <class _Tp>
911inline constexpr bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
912#endif
913
914#else // __has_keyword(__is_lvalue_reference) && etc...
915
916template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
917template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
918
919template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
920template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
921
922template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
923template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
924template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
925
926#if _LIBCPP_STD_VER > 14
927template <class _Tp>
928inline constexpr bool is_reference_v = is_reference<_Tp>::value;
929
930template <class _Tp>
931inline constexpr bool is_lvalue_reference_v = is_lvalue_reference<_Tp>::value;
932
933template <class _Tp>
934inline constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
935#endif
936
937#endif // __has_keyword(__is_lvalue_reference) && etc...
938
939// is_union
940
941#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
942
943template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
944    : public integral_constant<bool, __is_union(_Tp)> {};
945
946#else
947
948template <class _Tp> struct __libcpp_union : public false_type {};
949template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
950    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
951
952#endif
953
954#if _LIBCPP_STD_VER > 14
955template <class _Tp>
956inline constexpr bool is_union_v = is_union<_Tp>::value;
957#endif
958
959// is_class
960
961#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
962
963template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
964    : public integral_constant<bool, __is_class(_Tp)> {};
965
966#else
967
968namespace __is_class_imp
969{
970template <class _Tp> char  __test(int _Tp::*);
971template <class _Tp> __two __test(...);
972}
973
974template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
975    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
976
977#endif
978
979#if _LIBCPP_STD_VER > 14
980template <class _Tp>
981inline constexpr bool is_class_v = is_class<_Tp>::value;
982#endif
983
984// is_function
985
986template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
987    : public _BoolConstant<
988#ifdef __clang__
989    __is_function(_Tp)
990#else
991 !(is_reference<_Tp>::value || is_const<const _Tp>::value)
992#endif
993    > {};
994
995
996#if _LIBCPP_STD_VER > 14
997template <class _Tp>
998inline constexpr bool is_function_v = is_function<_Tp>::value;
999#endif
1000
1001template <class _Tp> struct __libcpp_is_member_pointer {
1002  enum {
1003    __is_member = false,
1004    __is_func = false,
1005    __is_obj = false
1006  };
1007};
1008template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
1009  enum {
1010    __is_member = true,
1011    __is_func = is_function<_Tp>::value,
1012    __is_obj = !__is_func,
1013  };
1014};
1015
1016#if __has_keyword(__is_member_function_pointer)
1017
1018template<class _Tp>
1019struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1020    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
1021
1022#if _LIBCPP_STD_VER > 14
1023template <class _Tp>
1024inline constexpr bool is_member_function_pointer_v = __is_member_function_pointer(_Tp);
1025#endif
1026
1027#else // __has_keyword(__is_member_function_pointer)
1028
1029template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
1030    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
1031
1032#if _LIBCPP_STD_VER > 14
1033template <class _Tp>
1034inline constexpr bool is_member_function_pointer_v = is_member_function_pointer<_Tp>::value;
1035#endif
1036
1037#endif // __has_keyword(__is_member_function_pointer)
1038
1039// is_member_pointer
1040
1041#if __has_keyword(__is_member_pointer)
1042
1043template<class _Tp>
1044struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
1045
1046#if _LIBCPP_STD_VER > 14
1047template <class _Tp>
1048inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
1049#endif
1050
1051#else // __has_keyword(__is_member_pointer)
1052
1053template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
1054 : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
1055
1056#if _LIBCPP_STD_VER > 14
1057template <class _Tp>
1058inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
1059#endif
1060
1061#endif // __has_keyword(__is_member_pointer)
1062
1063// is_member_object_pointer
1064
1065#if __has_keyword(__is_member_object_pointer)
1066
1067template<class _Tp>
1068struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1069    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
1070
1071#if _LIBCPP_STD_VER > 14
1072template <class _Tp>
1073inline constexpr bool is_member_object_pointer_v = __is_member_object_pointer(_Tp);
1074#endif
1075
1076#else // __has_keyword(__is_member_object_pointer)
1077
1078template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
1079    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
1080
1081#if _LIBCPP_STD_VER > 14
1082template <class _Tp>
1083inline constexpr bool is_member_object_pointer_v = is_member_object_pointer<_Tp>::value;
1084#endif
1085
1086#endif // __has_keyword(__is_member_object_pointer)
1087
1088// is_enum
1089
1090#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1091
1092template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1093    : public integral_constant<bool, __is_enum(_Tp)> {};
1094
1095#if _LIBCPP_STD_VER > 14
1096template <class _Tp>
1097inline constexpr bool is_enum_v = __is_enum(_Tp);
1098#endif
1099
1100#else
1101
1102template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
1103    : public integral_constant<bool, !is_void<_Tp>::value             &&
1104                                     !is_integral<_Tp>::value         &&
1105                                     !is_floating_point<_Tp>::value   &&
1106                                     !is_array<_Tp>::value            &&
1107                                     !is_pointer<_Tp>::value          &&
1108                                     !is_reference<_Tp>::value        &&
1109                                     !is_member_pointer<_Tp>::value   &&
1110                                     !is_union<_Tp>::value            &&
1111                                     !is_class<_Tp>::value            &&
1112                                     !is_function<_Tp>::value         > {};
1113
1114#if _LIBCPP_STD_VER > 14
1115template <class _Tp>
1116inline constexpr bool is_enum_v = is_enum<_Tp>::value;
1117#endif
1118
1119#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
1120
1121// is_arithmetic
1122
1123
1124template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
1125    : public integral_constant<bool, is_integral<_Tp>::value      ||
1126                                     is_floating_point<_Tp>::value> {};
1127
1128#if _LIBCPP_STD_VER > 14
1129template <class _Tp>
1130inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
1131#endif
1132
1133// is_fundamental
1134
1135// Before Clang 10, __is_fundamental didn't work for nullptr_t.
1136// In C++03 nullptr_t is library-provided but must still count as "fundamental."
1137#if __has_keyword(__is_fundamental) &&                                         \
1138    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
1139    !defined(_LIBCPP_CXX03_LANG)
1140
1141template<class _Tp>
1142struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
1143
1144#if _LIBCPP_STD_VER > 14
1145template <class _Tp>
1146inline constexpr bool is_fundamental_v = __is_fundamental(_Tp);
1147#endif
1148
1149#else // __has_keyword(__is_fundamental)
1150
1151template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
1152    : public integral_constant<bool, is_void<_Tp>::value        ||
1153                                     __is_nullptr_t<_Tp>::value ||
1154                                     is_arithmetic<_Tp>::value> {};
1155
1156#if _LIBCPP_STD_VER > 14
1157template <class _Tp>
1158inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
1159#endif
1160
1161#endif // __has_keyword(__is_fundamental)
1162
1163// is_scalar
1164
1165// In C++03 nullptr_t is library-provided but must still count as "scalar."
1166#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
1167
1168template<class _Tp>
1169struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
1170
1171#if _LIBCPP_STD_VER > 14
1172template <class _Tp>
1173inline constexpr bool is_scalar_v = __is_scalar(_Tp);
1174#endif
1175
1176#else // __has_keyword(__is_scalar)
1177
1178template <class _Tp> struct __is_block : false_type {};
1179#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
1180template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
1181#endif
1182
1183template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
1184    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
1185                                     is_member_pointer<_Tp>::value ||
1186                                     is_pointer<_Tp>::value        ||
1187                                     __is_nullptr_t<_Tp>::value    ||
1188                                     __is_block<_Tp>::value        ||
1189                                     is_enum<_Tp>::value           > {};
1190
1191template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
1192
1193#if _LIBCPP_STD_VER > 14
1194template <class _Tp>
1195inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
1196#endif
1197
1198#endif // __has_keyword(__is_scalar)
1199
1200// is_object
1201
1202#if __has_keyword(__is_object)
1203
1204template<class _Tp>
1205struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
1206
1207#if _LIBCPP_STD_VER > 14
1208template <class _Tp>
1209inline constexpr bool is_object_v = __is_object(_Tp);
1210#endif
1211
1212#else // __has_keyword(__is_object)
1213
1214template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
1215    : public integral_constant<bool, is_scalar<_Tp>::value ||
1216                                     is_array<_Tp>::value  ||
1217                                     is_union<_Tp>::value  ||
1218                                     is_class<_Tp>::value  > {};
1219
1220#if _LIBCPP_STD_VER > 14
1221template <class _Tp>
1222inline constexpr bool is_object_v = is_object<_Tp>::value;
1223#endif
1224
1225#endif // __has_keyword(__is_object)
1226
1227// is_compound
1228
1229// >= 11 because in C++03 nullptr isn't actually nullptr
1230#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
1231
1232template<class _Tp>
1233struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
1234
1235#if _LIBCPP_STD_VER > 14
1236template <class _Tp>
1237inline constexpr bool is_compound_v = __is_compound(_Tp);
1238#endif
1239
1240#else // __has_keyword(__is_compound)
1241
1242template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
1243    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
1244
1245#if _LIBCPP_STD_VER > 14
1246template <class _Tp>
1247inline constexpr bool is_compound_v = is_compound<_Tp>::value;
1248#endif
1249
1250#endif // __has_keyword(__is_compound)
1251
1252// __is_referenceable  [defns.referenceable]
1253
1254struct __is_referenceable_impl {
1255    template <class _Tp> static _Tp& __test(int);
1256    template <class _Tp> static __two __test(...);
1257};
1258
1259template <class _Tp>
1260struct __is_referenceable : integral_constant<bool,
1261    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
1262
1263
1264// add_const
1265
1266template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
1267  typedef _LIBCPP_NODEBUG const _Tp type;
1268};
1269
1270#if _LIBCPP_STD_VER > 11
1271template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
1272#endif
1273
1274// add_volatile
1275
1276template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
1277  typedef _LIBCPP_NODEBUG volatile _Tp type;
1278};
1279
1280#if _LIBCPP_STD_VER > 11
1281template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
1282#endif
1283
1284// add_cv
1285template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
1286  typedef _LIBCPP_NODEBUG const volatile _Tp type;
1287};
1288
1289#if _LIBCPP_STD_VER > 11
1290template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
1291#endif
1292
1293// remove_reference
1294
1295#if __has_keyword(__remove_reference)
1296
1297template<class _Tp>
1298struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
1299
1300#else // __has_keyword(__remove_reference)
1301
1302template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG _Tp type;};
1303template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG _Tp type;};
1304template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG _Tp type;};
1305
1306#if _LIBCPP_STD_VER > 11
1307template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
1308#endif
1309
1310#endif // __has_keyword(__remove_reference)
1311
1312// add_lvalue_reference
1313
1314template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp  type; };
1315template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp& type; };
1316
1317template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
1318{typedef _LIBCPP_NODEBUG typename  __add_lvalue_reference_impl<_Tp>::type type;};
1319
1320#if _LIBCPP_STD_VER > 11
1321template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
1322#endif
1323
1324template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp   type; };
1325template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp&& type; };
1326
1327template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
1328{typedef _LIBCPP_NODEBUG typename __add_rvalue_reference_impl<_Tp>::type type;};
1329
1330#if _LIBCPP_STD_VER > 11
1331template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
1332#endif
1333
1334// Suppress deprecation notice for volatile-qualified return type resulting
1335// from volatile-qualified types _Tp.
1336_LIBCPP_SUPPRESS_DEPRECATED_PUSH
1337template <class _Tp> _Tp&& __declval(int);
1338template <class _Tp> _Tp   __declval(long);
1339_LIBCPP_SUPPRESS_DEPRECATED_POP
1340
1341template <class _Tp>
1342decltype(__declval<_Tp>(0))
1343declval() _NOEXCEPT;
1344
1345// __uncvref
1346
1347template <class _Tp>
1348struct __uncvref  {
1349    typedef _LIBCPP_NODEBUG typename remove_cv<typename remove_reference<_Tp>::type>::type type;
1350};
1351
1352template <class _Tp>
1353struct __unconstref {
1354    typedef _LIBCPP_NODEBUG typename remove_const<typename remove_reference<_Tp>::type>::type type;
1355};
1356
1357#ifndef _LIBCPP_CXX03_LANG
1358template <class _Tp>
1359using __uncvref_t _LIBCPP_NODEBUG = typename __uncvref<_Tp>::type;
1360#endif
1361
1362// __is_same_uncvref
1363
1364template <class _Tp, class _Up>
1365struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
1366                                   typename __uncvref<_Up>::type> {};
1367
1368#if _LIBCPP_STD_VER > 17
1369// remove_cvref - same as __uncvref
1370template <class _Tp>
1371struct remove_cvref : public __uncvref<_Tp> {};
1372
1373template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
1374#endif
1375
1376
1377struct __any
1378{
1379    __any(...);
1380};
1381
1382// remove_pointer
1383
1384template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG _Tp type;};
1385template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG _Tp type;};
1386template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG _Tp type;};
1387template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG _Tp type;};
1388template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG _Tp type;};
1389
1390#if _LIBCPP_STD_VER > 11
1391template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
1392#endif
1393
1394// add_pointer
1395
1396template <class _Tp,
1397        bool = __is_referenceable<_Tp>::value ||
1398                _IsSame<typename remove_cv<_Tp>::type, void>::value>
1399struct __add_pointer_impl
1400    {typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type* type;};
1401template <class _Tp> struct __add_pointer_impl<_Tp, false>
1402    {typedef _LIBCPP_NODEBUG _Tp type;};
1403
1404template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
1405    {typedef _LIBCPP_NODEBUG typename __add_pointer_impl<_Tp>::type type;};
1406
1407#if _LIBCPP_STD_VER > 11
1408template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
1409#endif
1410
1411// type_identity
1412#if _LIBCPP_STD_VER > 17
1413template<class _Tp> struct type_identity { typedef _Tp type; };
1414template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
1415#endif
1416
1417// is_signed
1418
1419#if __has_keyword(__is_signed)
1420
1421template<class _Tp>
1422struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
1423
1424#if _LIBCPP_STD_VER > 14
1425template <class _Tp>
1426inline constexpr bool is_signed_v = __is_signed(_Tp);
1427#endif
1428
1429#else // __has_keyword(__is_signed)
1430
1431template <class _Tp, bool = is_integral<_Tp>::value>
1432struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
1433
1434template <class _Tp>
1435struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
1436
1437template <class _Tp, bool = is_arithmetic<_Tp>::value>
1438struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
1439
1440template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
1441
1442template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
1443
1444#if _LIBCPP_STD_VER > 14
1445template <class _Tp>
1446inline constexpr bool is_signed_v = is_signed<_Tp>::value;
1447#endif
1448
1449#endif // __has_keyword(__is_signed)
1450
1451// is_unsigned
1452
1453// Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
1454// No currently-released version of AppleClang contains the fixed intrinsic.
1455#if __has_keyword(__is_unsigned) &&                                            \
1456    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) &&               \
1457    !defined(_LIBCPP_APPLE_CLANG_VER)
1458
1459template<class _Tp>
1460struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
1461
1462#if _LIBCPP_STD_VER > 14
1463template <class _Tp>
1464inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
1465#endif
1466
1467#else // __has_keyword(__is_unsigned)
1468
1469template <class _Tp, bool = is_integral<_Tp>::value>
1470struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
1471
1472template <class _Tp>
1473struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
1474
1475template <class _Tp, bool = is_arithmetic<_Tp>::value>
1476struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
1477
1478template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
1479
1480template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
1481
1482#if _LIBCPP_STD_VER > 14
1483template <class _Tp>
1484inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
1485#endif
1486
1487#endif // __has_keyword(__is_unsigned)
1488
1489// rank
1490
1491template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
1492    : public integral_constant<size_t, 0> {};
1493template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
1494    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1495template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
1496    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
1497
1498#if _LIBCPP_STD_VER > 14
1499template <class _Tp>
1500inline constexpr size_t rank_v = rank<_Tp>::value;
1501#endif
1502
1503// extent
1504
1505#if __has_keyword(__array_extent)
1506
1507template<class _Tp, size_t _Dim = 0>
1508struct _LIBCPP_TEMPLATE_VIS extent
1509    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
1510
1511#if _LIBCPP_STD_VER > 14
1512template <class _Tp, unsigned _Ip = 0>
1513inline constexpr size_t extent_v = __array_extent(_Tp, _Ip);
1514#endif
1515
1516#else // __has_keyword(__array_extent)
1517
1518template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
1519    : public integral_constant<size_t, 0> {};
1520template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
1521    : public integral_constant<size_t, 0> {};
1522template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
1523    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1524template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
1525    : public integral_constant<size_t, _Np> {};
1526template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
1527    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
1528
1529#if _LIBCPP_STD_VER > 14
1530template <class _Tp, unsigned _Ip = 0>
1531inline constexpr size_t extent_v = extent<_Tp, _Ip>::value;
1532#endif
1533
1534#endif // __has_keyword(__array_extent)
1535
1536// remove_extent
1537
1538template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
1539    {typedef _Tp type;};
1540template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
1541    {typedef _Tp type;};
1542template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
1543    {typedef _Tp type;};
1544
1545#if _LIBCPP_STD_VER > 11
1546template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
1547#endif
1548
1549// remove_all_extents
1550
1551template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
1552    {typedef _Tp type;};
1553template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
1554    {typedef typename remove_all_extents<_Tp>::type type;};
1555template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
1556    {typedef typename remove_all_extents<_Tp>::type type;};
1557
1558#if _LIBCPP_STD_VER > 11
1559template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
1560#endif
1561
1562#if _LIBCPP_STD_VER > 17
1563// is_bounded_array
1564
1565template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
1566template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
1567
1568template <class _Tp>
1569inline constexpr
1570bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
1571
1572// is_unbounded_array
1573
1574template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
1575template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
1576
1577template <class _Tp>
1578inline constexpr
1579bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
1580#endif
1581
1582// decay
1583
1584template <class _Up, bool>
1585struct __decay {
1586    typedef _LIBCPP_NODEBUG typename remove_cv<_Up>::type type;
1587};
1588
1589template <class _Up>
1590struct __decay<_Up, true> {
1591public:
1592    typedef _LIBCPP_NODEBUG typename conditional
1593                     <
1594                         is_array<_Up>::value,
1595                         typename remove_extent<_Up>::type*,
1596                         typename conditional
1597                         <
1598                              is_function<_Up>::value,
1599                              typename add_pointer<_Up>::type,
1600                              typename remove_cv<_Up>::type
1601                         >::type
1602                     >::type type;
1603};
1604
1605template <class _Tp>
1606struct _LIBCPP_TEMPLATE_VIS decay
1607{
1608private:
1609    typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type _Up;
1610public:
1611    typedef _LIBCPP_NODEBUG typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
1612};
1613
1614#if _LIBCPP_STD_VER > 11
1615template <class _Tp> using decay_t = typename decay<_Tp>::type;
1616#endif
1617
1618// is_abstract
1619
1620template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
1621    : public integral_constant<bool, __is_abstract(_Tp)> {};
1622
1623#if _LIBCPP_STD_VER > 14
1624template <class _Tp>
1625inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
1626#endif
1627
1628// is_final
1629
1630template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1631__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
1632
1633#if _LIBCPP_STD_VER > 11
1634template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1635is_final : public integral_constant<bool, __is_final(_Tp)> {};
1636#endif
1637
1638#if _LIBCPP_STD_VER > 14
1639template <class _Tp>
1640inline constexpr bool is_final_v = is_final<_Tp>::value;
1641#endif
1642
1643// is_aggregate
1644#if _LIBCPP_STD_VER > 14
1645
1646template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
1647is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
1648
1649template <class _Tp>
1650inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
1651
1652#endif // _LIBCPP_STD_VER > 14
1653
1654// is_base_of
1655
1656template <class _Bp, class _Dp>
1657struct _LIBCPP_TEMPLATE_VIS is_base_of
1658    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
1659
1660#if _LIBCPP_STD_VER > 14
1661template <class _Bp, class _Dp>
1662inline constexpr bool is_base_of_v = is_base_of<_Bp, _Dp>::value;
1663#endif
1664
1665// __is_core_convertible
1666
1667// [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed.
1668// We can't test for that, but we can test implicit convertibility by passing it
1669// to a function. Notice that __is_core_convertible<void,void> is false,
1670// and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later.
1671
1672template <class _Tp, class _Up, class = void>
1673struct __is_core_convertible : public false_type {};
1674
1675template <class _Tp, class _Up>
1676struct __is_core_convertible<_Tp, _Up, decltype(
1677    static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() )
1678)> : public true_type {};
1679
1680// is_convertible
1681
1682#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
1683
1684template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1685    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
1686
1687#else  // __has_feature(is_convertible_to)
1688
1689namespace __is_convertible_imp
1690{
1691template <class _Tp> void  __test_convert(_Tp);
1692
1693template <class _From, class _To, class = void>
1694struct __is_convertible_test : public false_type {};
1695
1696template <class _From, class _To>
1697struct __is_convertible_test<_From, _To,
1698    decltype(__is_convertible_imp::__test_convert<_To>(declval<_From>()))> : public true_type
1699{};
1700
1701template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
1702                     bool _IsFunction = is_function<_Tp>::value,
1703                     bool _IsVoid =     is_void<_Tp>::value>
1704                     struct __is_array_function_or_void                          {enum {value = 0};};
1705template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
1706template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
1707template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
1708}
1709
1710template <class _Tp,
1711    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
1712struct __is_convertible_check
1713{
1714    static const size_t __v = 0;
1715};
1716
1717template <class _Tp>
1718struct __is_convertible_check<_Tp, 0>
1719{
1720    static const size_t __v = sizeof(_Tp);
1721};
1722
1723template <class _T1, class _T2,
1724    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
1725    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
1726struct __is_convertible
1727    : public integral_constant<bool,
1728        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
1729    >
1730{};
1731
1732template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
1733template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
1734template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
1735template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
1736
1737template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
1738template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
1739template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
1740template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
1741
1742template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
1743template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
1744template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
1745template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
1746
1747template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
1748    : public __is_convertible<_T1, _T2>
1749{
1750    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
1751    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
1752};
1753
1754#endif // __has_feature(is_convertible_to)
1755
1756#if _LIBCPP_STD_VER > 14
1757template <class _From, class _To>
1758inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
1759#endif
1760
1761// is_nothrow_convertible
1762
1763#if _LIBCPP_STD_VER > 17
1764
1765template <typename _Tp>
1766static void __test_noexcept(_Tp) noexcept;
1767
1768template<typename _Fm, typename _To>
1769static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
1770__is_nothrow_convertible_test();
1771
1772template <typename _Fm, typename _To>
1773struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
1774{ };
1775
1776template <typename _Fm, typename _To>
1777struct is_nothrow_convertible : _Or<
1778    _And<is_void<_To>, is_void<_Fm>>,
1779    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
1780>::type { };
1781
1782template <typename _Fm, typename _To>
1783inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
1784
1785#endif // _LIBCPP_STD_VER > 17
1786
1787// is_empty
1788
1789#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
1790
1791template <class _Tp>
1792struct _LIBCPP_TEMPLATE_VIS is_empty
1793    : public integral_constant<bool, __is_empty(_Tp)> {};
1794
1795#else  // __has_feature(is_empty)
1796
1797template <class _Tp>
1798struct __is_empty1
1799    : public _Tp
1800{
1801    double __lx;
1802};
1803
1804struct __is_empty2
1805{
1806    double __lx;
1807};
1808
1809template <class _Tp, bool = is_class<_Tp>::value>
1810struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
1811
1812template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
1813
1814template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
1815
1816#endif // __has_feature(is_empty)
1817
1818#if _LIBCPP_STD_VER > 14
1819template <class _Tp>
1820inline constexpr bool is_empty_v = is_empty<_Tp>::value;
1821#endif
1822
1823// is_polymorphic
1824
1825#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
1826
1827template <class _Tp>
1828struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1829    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
1830
1831#else
1832
1833template<typename _Tp> char &__is_polymorphic_impl(
1834    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
1835                       int>::type);
1836template<typename _Tp> __two &__is_polymorphic_impl(...);
1837
1838template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
1839    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
1840
1841#endif // __has_feature(is_polymorphic)
1842
1843#if _LIBCPP_STD_VER > 14
1844template <class _Tp>
1845inline constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
1846#endif
1847
1848// has_virtual_destructor
1849
1850#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
1851
1852template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1853    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
1854
1855#else
1856
1857template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
1858    : public false_type {};
1859
1860#endif
1861
1862#if _LIBCPP_STD_VER > 14
1863template <class _Tp>
1864inline constexpr bool has_virtual_destructor_v = has_virtual_destructor<_Tp>::value;
1865#endif
1866
1867// has_unique_object_representations
1868
1869#if _LIBCPP_STD_VER > 14
1870
1871template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
1872    : public integral_constant<bool,
1873       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
1874
1875template <class _Tp>
1876inline constexpr bool has_unique_object_representations_v = has_unique_object_representations<_Tp>::value;
1877
1878#endif
1879
1880// alignment_of
1881
1882template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
1883    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
1884
1885#if _LIBCPP_STD_VER > 14
1886template <class _Tp>
1887inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
1888#endif
1889
1890// aligned_storage
1891
1892template <class _Hp, class _Tp>
1893struct __type_list
1894{
1895    typedef _Hp _Head;
1896    typedef _Tp _Tail;
1897};
1898
1899struct __nat
1900{
1901#ifndef _LIBCPP_CXX03_LANG
1902    __nat() = delete;
1903    __nat(const __nat&) = delete;
1904    __nat& operator=(const __nat&) = delete;
1905    ~__nat() = delete;
1906#endif
1907};
1908
1909template <class _Tp>
1910struct __align_type
1911{
1912    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
1913    typedef _Tp type;
1914};
1915
1916struct __struct_double {long double __lx;};
1917struct __struct_double4 {double __lx[4];};
1918
1919typedef
1920    __type_list<__align_type<unsigned char>,
1921    __type_list<__align_type<unsigned short>,
1922    __type_list<__align_type<unsigned int>,
1923    __type_list<__align_type<unsigned long>,
1924    __type_list<__align_type<unsigned long long>,
1925    __type_list<__align_type<double>,
1926    __type_list<__align_type<long double>,
1927    __type_list<__align_type<__struct_double>,
1928    __type_list<__align_type<__struct_double4>,
1929    __type_list<__align_type<int*>,
1930    __nat
1931    > > > > > > > > > > __all_types;
1932
1933template <size_t _Align>
1934struct _ALIGNAS(_Align) __fallback_overaligned {};
1935
1936template <class _TL, size_t _Align> struct __find_pod;
1937
1938template <class _Hp, size_t _Align>
1939struct __find_pod<__type_list<_Hp, __nat>, _Align>
1940{
1941    typedef typename conditional<
1942                             _Align == _Hp::value,
1943                             typename _Hp::type,
1944                             __fallback_overaligned<_Align>
1945                         >::type type;
1946};
1947
1948template <class _Hp, class _Tp, size_t _Align>
1949struct __find_pod<__type_list<_Hp, _Tp>, _Align>
1950{
1951    typedef typename conditional<
1952                             _Align == _Hp::value,
1953                             typename _Hp::type,
1954                             typename __find_pod<_Tp, _Align>::type
1955                         >::type type;
1956};
1957
1958template <class _TL, size_t _Len> struct __find_max_align;
1959
1960template <class _Hp, size_t _Len>
1961struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
1962
1963template <size_t _Len, size_t _A1, size_t _A2>
1964struct __select_align
1965{
1966private:
1967    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
1968    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
1969public:
1970    static const size_t value = _Len < __max ? __min : __max;
1971};
1972
1973template <class _Hp, class _Tp, size_t _Len>
1974struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
1975    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
1976
1977template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1978struct _LIBCPP_TEMPLATE_VIS aligned_storage
1979{
1980    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
1981    union type
1982    {
1983        _Aligner __align;
1984        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
1985    };
1986};
1987
1988#if _LIBCPP_STD_VER > 11
1989template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
1990    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
1991#endif
1992
1993#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
1994template <size_t _Len>\
1995struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
1996{\
1997    struct _ALIGNAS(n) type\
1998    {\
1999        unsigned char __lx[(_Len + n - 1)/n * n];\
2000    };\
2001}
2002
2003_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
2004_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
2005_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
2006_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
2007_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
2008_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
2009_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
2010_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
2011_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
2012_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
2013_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
2014_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
2015_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
2016_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
2017// PE/COFF does not support alignment beyond 8192 (=0x2000)
2018#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2019_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
2020#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
2021
2022#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
2023
2024
2025// aligned_union
2026
2027template <size_t _I0, size_t ..._In>
2028struct __static_max;
2029
2030template <size_t _I0>
2031struct __static_max<_I0>
2032{
2033    static const size_t value = _I0;
2034};
2035
2036template <size_t _I0, size_t _I1, size_t ..._In>
2037struct __static_max<_I0, _I1, _In...>
2038{
2039    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
2040                                             __static_max<_I1, _In...>::value;
2041};
2042
2043template <size_t _Len, class _Type0, class ..._Types>
2044struct aligned_union
2045{
2046    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
2047                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
2048    static const size_t __len = __static_max<_Len, sizeof(_Type0),
2049                                             sizeof(_Types)...>::value;
2050    typedef typename aligned_storage<__len, alignment_value>::type type;
2051};
2052
2053#if _LIBCPP_STD_VER > 11
2054template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
2055#endif
2056
2057template <class _Tp>
2058struct __numeric_type
2059{
2060   static void __test(...);
2061   static float __test(float);
2062   static double __test(char);
2063   static double __test(int);
2064   static double __test(unsigned);
2065   static double __test(long);
2066   static double __test(unsigned long);
2067   static double __test(long long);
2068   static double __test(unsigned long long);
2069   static double __test(double);
2070   static long double __test(long double);
2071
2072   typedef decltype(__test(declval<_Tp>())) type;
2073   static const bool value = _IsNotSame<type, void>::value;
2074};
2075
2076template <>
2077struct __numeric_type<void>
2078{
2079   static const bool value = true;
2080};
2081
2082// __promote
2083
2084template <class _A1, class _A2 = void, class _A3 = void,
2085          bool = __numeric_type<_A1>::value &&
2086                 __numeric_type<_A2>::value &&
2087                 __numeric_type<_A3>::value>
2088class __promote_imp
2089{
2090public:
2091    static const bool value = false;
2092};
2093
2094template <class _A1, class _A2, class _A3>
2095class __promote_imp<_A1, _A2, _A3, true>
2096{
2097private:
2098    typedef typename __promote_imp<_A1>::type __type1;
2099    typedef typename __promote_imp<_A2>::type __type2;
2100    typedef typename __promote_imp<_A3>::type __type3;
2101public:
2102    typedef decltype(__type1() + __type2() + __type3()) type;
2103    static const bool value = true;
2104};
2105
2106template <class _A1, class _A2>
2107class __promote_imp<_A1, _A2, void, true>
2108{
2109private:
2110    typedef typename __promote_imp<_A1>::type __type1;
2111    typedef typename __promote_imp<_A2>::type __type2;
2112public:
2113    typedef decltype(__type1() + __type2()) type;
2114    static const bool value = true;
2115};
2116
2117template <class _A1>
2118class __promote_imp<_A1, void, void, true>
2119{
2120public:
2121    typedef typename __numeric_type<_A1>::type type;
2122    static const bool value = true;
2123};
2124
2125template <class _A1, class _A2 = void, class _A3 = void>
2126class __promote : public __promote_imp<_A1, _A2, _A3> {};
2127
2128// make_signed / make_unsigned
2129
2130typedef
2131    __type_list<signed char,
2132    __type_list<signed short,
2133    __type_list<signed int,
2134    __type_list<signed long,
2135    __type_list<signed long long,
2136#ifndef _LIBCPP_HAS_NO_INT128
2137    __type_list<__int128_t,
2138#endif
2139    __nat
2140#ifndef _LIBCPP_HAS_NO_INT128
2141    >
2142#endif
2143    > > > > > __signed_types;
2144
2145typedef
2146    __type_list<unsigned char,
2147    __type_list<unsigned short,
2148    __type_list<unsigned int,
2149    __type_list<unsigned long,
2150    __type_list<unsigned long long,
2151#ifndef _LIBCPP_HAS_NO_INT128
2152    __type_list<__uint128_t,
2153#endif
2154    __nat
2155#ifndef _LIBCPP_HAS_NO_INT128
2156    >
2157#endif
2158    > > > > > __unsigned_types;
2159
2160template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
2161
2162template <class _Hp, class _Tp, size_t _Size>
2163struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
2164{
2165    typedef _LIBCPP_NODEBUG _Hp type;
2166};
2167
2168template <class _Hp, class _Tp, size_t _Size>
2169struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
2170{
2171    typedef _LIBCPP_NODEBUG typename __find_first<_Tp, _Size>::type type;
2172};
2173
2174template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
2175                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
2176struct __apply_cv
2177{
2178    typedef _LIBCPP_NODEBUG _Up type;
2179};
2180
2181template <class _Tp, class _Up>
2182struct __apply_cv<_Tp, _Up, true, false>
2183{
2184    typedef _LIBCPP_NODEBUG const _Up type;
2185};
2186
2187template <class _Tp, class _Up>
2188struct __apply_cv<_Tp, _Up, false, true>
2189{
2190    typedef volatile _Up type;
2191};
2192
2193template <class _Tp, class _Up>
2194struct __apply_cv<_Tp, _Up, true, true>
2195{
2196    typedef const volatile _Up type;
2197};
2198
2199template <class _Tp, class _Up>
2200struct __apply_cv<_Tp&, _Up, false, false>
2201{
2202    typedef _Up& type;
2203};
2204
2205template <class _Tp, class _Up>
2206struct __apply_cv<_Tp&, _Up, true, false>
2207{
2208    typedef const _Up& type;
2209};
2210
2211template <class _Tp, class _Up>
2212struct __apply_cv<_Tp&, _Up, false, true>
2213{
2214    typedef volatile _Up& type;
2215};
2216
2217template <class _Tp, class _Up>
2218struct __apply_cv<_Tp&, _Up, true, true>
2219{
2220    typedef const volatile _Up& type;
2221};
2222
2223template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2224struct __make_signed {};
2225
2226template <class _Tp>
2227struct __make_signed<_Tp, true>
2228{
2229    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
2230};
2231
2232template <> struct __make_signed<bool,               true> {};
2233template <> struct __make_signed<  signed short,     true> {typedef short     type;};
2234template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
2235template <> struct __make_signed<  signed int,       true> {typedef int       type;};
2236template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
2237template <> struct __make_signed<  signed long,      true> {typedef long      type;};
2238template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
2239template <> struct __make_signed<  signed long long, true> {typedef long long type;};
2240template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
2241#ifndef _LIBCPP_HAS_NO_INT128
2242template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
2243template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
2244#endif
2245
2246template <class _Tp>
2247struct _LIBCPP_TEMPLATE_VIS make_signed
2248{
2249    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
2250};
2251
2252#if _LIBCPP_STD_VER > 11
2253template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
2254#endif
2255
2256template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
2257struct __make_unsigned {};
2258
2259template <class _Tp>
2260struct __make_unsigned<_Tp, true>
2261{
2262    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
2263};
2264
2265template <> struct __make_unsigned<bool,               true> {};
2266template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
2267template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
2268template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
2269template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
2270template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
2271template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
2272template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
2273template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
2274#ifndef _LIBCPP_HAS_NO_INT128
2275template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
2276template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
2277#endif
2278
2279template <class _Tp>
2280struct _LIBCPP_TEMPLATE_VIS make_unsigned
2281{
2282    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
2283};
2284
2285#if _LIBCPP_STD_VER > 11
2286template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
2287#endif
2288
2289#ifndef _LIBCPP_CXX03_LANG
2290template <class _Tp>
2291_LIBCPP_HIDE_FROM_ABI constexpr
2292typename make_unsigned<_Tp>::type __to_unsigned_like(_Tp __x) noexcept {
2293    return static_cast<typename make_unsigned<_Tp>::type>(__x);
2294}
2295#endif
2296
2297#if _LIBCPP_STD_VER > 14
2298template <class...> using void_t = void;
2299#endif
2300
2301#if _LIBCPP_STD_VER > 17
2302// Let COND_RES(X, Y) be:
2303template <class _Tp, class _Up>
2304using __cond_type = decltype(false ? declval<_Tp>() : declval<_Up>());
2305
2306template <class _Tp, class _Up, class = void>
2307struct __common_type3 {};
2308
2309// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
2310template <class _Tp, class _Up>
2311struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
2312{
2313    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
2314};
2315
2316template <class _Tp, class _Up, class = void>
2317struct __common_type2_imp : __common_type3<_Tp, _Up> {};
2318#else
2319template <class _Tp, class _Up, class = void>
2320struct __common_type2_imp {};
2321#endif
2322
2323// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
2324template <class _Tp, class _Up>
2325struct __common_type2_imp<_Tp, _Up,
2326                          typename __void_t<decltype(
2327                                            true ? declval<_Tp>() : declval<_Up>()
2328                                            )>::type>
2329{
2330  typedef _LIBCPP_NODEBUG typename decay<decltype(
2331                         true ? declval<_Tp>() : declval<_Up>()
2332                         )>::type type;
2333};
2334
2335template <class, class = void>
2336struct __common_type_impl {};
2337
2338// Clang provides variadic templates in C++03 as an extension.
2339#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
2340# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
2341template <class... Tp>
2342struct __common_types;
2343template <class... _Tp>
2344struct _LIBCPP_TEMPLATE_VIS common_type;
2345#else
2346# define _LIBCPP_OPTIONAL_PACK(...)
2347struct __no_arg;
2348template <class _Tp, class _Up, class = __no_arg>
2349struct __common_types;
2350template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
2351          class _Unused = __no_arg>
2352struct common_type {
2353  static_assert(sizeof(_Unused) == 0,
2354                "common_type accepts at most 3 arguments in C++03");
2355};
2356#endif // _LIBCPP_CXX03_LANG
2357
2358template <class _Tp, class _Up>
2359struct __common_type_impl<
2360    __common_types<_Tp, _Up>,
2361    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2362{
2363  typedef typename common_type<_Tp, _Up>::type type;
2364};
2365
2366template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2367struct __common_type_impl<
2368    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
2369    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
2370    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
2371                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
2372};
2373
2374// bullet 1 - sizeof...(Tp) == 0
2375
2376template <>
2377struct _LIBCPP_TEMPLATE_VIS common_type<> {};
2378
2379// bullet 2 - sizeof...(Tp) == 1
2380
2381template <class _Tp>
2382struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
2383    : public common_type<_Tp, _Tp> {};
2384
2385// bullet 3 - sizeof...(Tp) == 2
2386
2387// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
2388template <class _Tp, class _Up>
2389struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
2390    : conditional<
2391        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
2392        __common_type2_imp<_Tp, _Up>,
2393        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
2394    >::type
2395{};
2396
2397// bullet 4 - sizeof...(Tp) > 2
2398
2399template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
2400struct _LIBCPP_TEMPLATE_VIS
2401    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
2402    : __common_type_impl<
2403          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
2404
2405#undef _LIBCPP_OPTIONAL_PACK
2406
2407#if _LIBCPP_STD_VER > 11
2408template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
2409#endif
2410
2411#if _LIBCPP_STD_VER > 11
2412// Let COPYCV(FROM, TO) be an alias for type TO with the addition of FROM's
2413// top-level cv-qualifiers.
2414template <class _From, class _To>
2415struct __copy_cv
2416{
2417    using type = _To;
2418};
2419
2420template <class _From, class _To>
2421struct __copy_cv<const _From, _To>
2422{
2423    using type = add_const_t<_To>;
2424};
2425
2426template <class _From, class _To>
2427struct __copy_cv<volatile _From, _To>
2428{
2429    using type = add_volatile_t<_To>;
2430};
2431
2432template <class _From, class _To>
2433struct __copy_cv<const volatile _From, _To>
2434{
2435    using type = add_cv_t<_To>;
2436};
2437
2438template <class _From, class _To>
2439using __copy_cv_t = typename __copy_cv<_From, _To>::type;
2440
2441template <class _From, class _To>
2442struct __copy_cvref
2443{
2444    using type = __copy_cv_t<_From, _To>;
2445};
2446
2447template <class _From, class _To>
2448struct __copy_cvref<_From&, _To>
2449{
2450    using type = add_lvalue_reference_t<__copy_cv_t<_From, _To>>;
2451};
2452
2453template <class _From, class _To>
2454struct __copy_cvref<_From&&, _To>
2455{
2456    using type = add_rvalue_reference_t<__copy_cv_t<_From, _To>>;
2457};
2458
2459template <class _From, class _To>
2460using __copy_cvref_t = typename __copy_cvref<_From, _To>::type;
2461
2462#endif // _LIBCPP_STD_VER > 11
2463
2464// common_reference
2465#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
2466// Let COND_RES(X, Y) be:
2467template <class _Xp, class _Yp>
2468using __cond_res =
2469    decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
2470
2471// Let `XREF(A)` denote a unary alias template `T` such that `T<U>` denotes the same type as `U`
2472// with the addition of `A`'s cv and reference qualifiers, for a non-reference cv-unqualified type
2473// `U`.
2474// [Note: `XREF(A)` is `__xref<A>::template __apply`]
2475template <class _Tp>
2476struct __xref {
2477  template<class _Up>
2478  using __apply = __copy_cvref_t<_Tp, _Up>;
2479};
2480
2481// Given types A and B, let X be remove_reference_t<A>, let Y be remove_reference_t<B>,
2482// and let COMMON-REF(A, B) be:
2483template<class _Ap, class _Bp, class _Xp = remove_reference_t<_Ap>, class _Yp = remove_reference_t<_Bp>>
2484struct __common_ref;
2485
2486template<class _Xp, class _Yp>
2487using __common_ref_t = typename __common_ref<_Xp, _Yp>::__type;
2488
2489template<class _Xp, class _Yp>
2490using __cv_cond_res = __cond_res<__copy_cv_t<_Xp, _Yp>&, __copy_cv_t<_Yp, _Xp>&>;
2491
2492
2493//    If A and B are both lvalue reference types, COMMON-REF(A, B) is
2494//    COND-RES(COPYCV(X, Y)&, COPYCV(Y, X)&) if that type exists and is a reference type.
2495template<class _Ap, class _Bp, class _Xp, class _Yp>
2496requires requires { typename __cv_cond_res<_Xp, _Yp>; } && is_reference_v<__cv_cond_res<_Xp, _Yp>>
2497struct __common_ref<_Ap&, _Bp&, _Xp, _Yp>
2498{
2499    using __type = __cv_cond_res<_Xp, _Yp>;
2500};
2501
2502//    Otherwise, let C be remove_reference_t<COMMON-REF(X&, Y&)>&&. ...
2503template <class _Xp, class _Yp>
2504using __common_ref_C = remove_reference_t<__common_ref_t<_Xp&, _Yp&>>&&;
2505
2506
2507//    .... If A and B are both rvalue reference types, C is well-formed, and
2508//    is_convertible_v<A, C> && is_convertible_v<B, C> is true, then COMMON-REF(A, B) is C.
2509template<class _Ap, class _Bp, class _Xp, class _Yp>
2510requires
2511  requires { typename __common_ref_C<_Xp, _Yp>; } &&
2512  is_convertible_v<_Ap&&, __common_ref_C<_Xp, _Yp>> &&
2513  is_convertible_v<_Bp&&, __common_ref_C<_Xp, _Yp>>
2514struct __common_ref<_Ap&&, _Bp&&, _Xp, _Yp>
2515{
2516    using __type = __common_ref_C<_Xp, _Yp>;
2517};
2518
2519//    Otherwise, let D be COMMON-REF(const X&, Y&). ...
2520template <class _Tp, class _Up>
2521using __common_ref_D = __common_ref_t<const _Tp&, _Up&>;
2522
2523//    ... If A is an rvalue reference and B is an lvalue reference and D is well-formed and
2524//    is_convertible_v<A, D> is true, then COMMON-REF(A, B) is D.
2525template<class _Ap, class _Bp, class _Xp, class _Yp>
2526requires requires { typename __common_ref_D<_Xp, _Yp>; } &&
2527         is_convertible_v<_Ap&&, __common_ref_D<_Xp, _Yp>>
2528struct __common_ref<_Ap&&, _Bp&, _Xp, _Yp>
2529{
2530    using __type = __common_ref_D<_Xp, _Yp>;
2531};
2532
2533//    Otherwise, if A is an lvalue reference and B is an rvalue reference, then
2534//    COMMON-REF(A, B) is COMMON-REF(B, A).
2535template<class _Ap, class _Bp, class _Xp, class _Yp>
2536struct __common_ref<_Ap&, _Bp&&, _Xp, _Yp> : __common_ref<_Bp&&, _Ap&> {};
2537
2538//    Otherwise, COMMON-REF(A, B) is ill-formed.
2539template<class _Ap, class _Bp, class _Xp, class _Yp>
2540struct __common_ref {};
2541
2542// Note C: For the common_reference trait applied to a parameter pack [...]
2543
2544template <class...>
2545struct common_reference;
2546
2547template <class... _Types>
2548using common_reference_t = typename common_reference<_Types...>::type;
2549
2550// bullet 1 - sizeof...(T) == 0
2551template<>
2552struct common_reference<> {};
2553
2554// bullet 2 - sizeof...(T) == 1
2555template <class _Tp>
2556struct common_reference<_Tp>
2557{
2558    using type = _Tp;
2559};
2560
2561// bullet 3 - sizeof...(T) == 2
2562template <class _Tp, class _Up> struct __common_reference_sub_bullet3;
2563template <class _Tp, class _Up> struct __common_reference_sub_bullet2 : __common_reference_sub_bullet3<_Tp, _Up> {};
2564template <class _Tp, class _Up> struct __common_reference_sub_bullet1 : __common_reference_sub_bullet2<_Tp, _Up> {};
2565
2566// sub-bullet 1 - If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, then
2567// the member typedef `type` denotes that type.
2568template <class _Tp, class _Up> struct common_reference<_Tp, _Up> : __common_reference_sub_bullet1<_Tp, _Up> {};
2569
2570template <class _Tp, class _Up>
2571requires is_reference_v<_Tp> && is_reference_v<_Up> && requires { typename __common_ref_t<_Tp, _Up>; }
2572struct __common_reference_sub_bullet1<_Tp, _Up>
2573{
2574    using type = __common_ref_t<_Tp, _Up>;
2575};
2576
2577// sub-bullet 2 - Otherwise, if basic_common_reference<remove_cvref_t<T1>, remove_cvref_t<T2>, XREF(T1), XREF(T2)>::type
2578// is well-formed, then the member typedef `type` denotes that type.
2579template <class, class, template <class> class, template <class> class> struct basic_common_reference {};
2580
2581template <class _Tp, class _Up>
2582using __basic_common_reference_t = typename basic_common_reference<
2583    remove_cvref_t<_Tp>, remove_cvref_t<_Up>,
2584    __xref<_Tp>::template __apply, __xref<_Up>::template __apply>::type;
2585
2586template <class _Tp, class _Up>
2587requires requires { typename __basic_common_reference_t<_Tp, _Up>; }
2588struct __common_reference_sub_bullet2<_Tp, _Up>
2589{
2590    using type = __basic_common_reference_t<_Tp, _Up>;
2591};
2592
2593// sub-bullet 3 - Otherwise, if COND-RES(T1, T2) is well-formed,
2594// then the member typedef `type` denotes that type.
2595template <class _Tp, class _Up>
2596requires requires { typename __cond_res<_Tp, _Up>; }
2597struct __common_reference_sub_bullet3<_Tp, _Up>
2598{
2599    using type = __cond_res<_Tp, _Up>;
2600};
2601
2602
2603// sub-bullet 4 & 5 - Otherwise, if common_type_t<T1, T2> is well-formed,
2604//                    then the member typedef `type` denotes that type.
2605//                  - Otherwise, there shall be no member `type`.
2606template <class _Tp, class _Up> struct __common_reference_sub_bullet3 : common_type<_Tp, _Up> {};
2607
2608// bullet 4 - If there is such a type `C`, the member typedef type shall denote the same type, if
2609//            any, as `common_reference_t<C, Rest...>`.
2610template <class _Tp, class _Up, class _Vp, class... _Rest>
2611requires requires { typename common_reference_t<_Tp, _Up>; }
2612struct common_reference<_Tp, _Up, _Vp, _Rest...>
2613    : common_reference<common_reference_t<_Tp, _Up>, _Vp, _Rest...>
2614{};
2615
2616// bullet 5 - Otherwise, there shall be no member `type`.
2617template <class...> struct common_reference {};
2618
2619#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
2620
2621// is_assignable
2622
2623template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG _Tp type; };
2624
2625#if __has_keyword(__is_assignable)
2626
2627template<class _Tp, class _Up>
2628struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
2629
2630#if _LIBCPP_STD_VER > 14
2631template <class _Tp, class _Arg>
2632inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Arg);
2633#endif
2634
2635#else // __has_keyword(__is_assignable)
2636
2637template <class _Tp, class _Arg>
2638typename __select_2nd<decltype((declval<_Tp>() = declval<_Arg>())), true_type>::type
2639__is_assignable_test(int);
2640
2641template <class, class>
2642false_type __is_assignable_test(...);
2643
2644
2645template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
2646struct __is_assignable_imp
2647    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
2648
2649template <class _Tp, class _Arg>
2650struct __is_assignable_imp<_Tp, _Arg, true>
2651    : public false_type
2652{
2653};
2654
2655template <class _Tp, class _Arg>
2656struct is_assignable
2657    : public __is_assignable_imp<_Tp, _Arg> {};
2658
2659#if _LIBCPP_STD_VER > 14
2660template <class _Tp, class _Arg>
2661inline constexpr bool is_assignable_v = is_assignable<_Tp, _Arg>::value;
2662#endif
2663
2664#endif // __has_keyword(__is_assignable)
2665
2666// is_copy_assignable
2667
2668template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
2669    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2670                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
2671
2672#if _LIBCPP_STD_VER > 14
2673template <class _Tp>
2674inline constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
2675#endif
2676
2677// is_move_assignable
2678
2679template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
2680    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
2681                           typename add_rvalue_reference<_Tp>::type> {};
2682
2683#if _LIBCPP_STD_VER > 14
2684template <class _Tp>
2685inline constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
2686#endif
2687
2688// is_destructible
2689
2690#if __has_keyword(__is_destructible)
2691
2692template<class _Tp>
2693struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
2694
2695#if _LIBCPP_STD_VER > 14
2696template <class _Tp>
2697inline constexpr bool is_destructible_v = __is_destructible(_Tp);
2698#endif
2699
2700#else // __has_keyword(__is_destructible)
2701
2702//  if it's a reference, return true
2703//  if it's a function, return false
2704//  if it's   void,     return false
2705//  if it's an array of unknown bound, return false
2706//  Otherwise, return "declval<_Up&>().~_Up()" is well-formed
2707//    where _Up is remove_all_extents<_Tp>::type
2708
2709template <class>
2710struct __is_destructible_apply { typedef int type; };
2711
2712template <typename _Tp>
2713struct __is_destructor_wellformed {
2714    template <typename _Tp1>
2715    static char  __test (
2716        typename __is_destructible_apply<decltype(declval<_Tp1&>().~_Tp1())>::type
2717    );
2718
2719    template <typename _Tp1>
2720    static __two __test (...);
2721
2722    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
2723};
2724
2725template <class _Tp, bool>
2726struct __destructible_imp;
2727
2728template <class _Tp>
2729struct __destructible_imp<_Tp, false>
2730   : public integral_constant<bool,
2731        __is_destructor_wellformed<typename remove_all_extents<_Tp>::type>::value> {};
2732
2733template <class _Tp>
2734struct __destructible_imp<_Tp, true>
2735    : public true_type {};
2736
2737template <class _Tp, bool>
2738struct __destructible_false;
2739
2740template <class _Tp>
2741struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, is_reference<_Tp>::value> {};
2742
2743template <class _Tp>
2744struct __destructible_false<_Tp, true> : public false_type {};
2745
2746template <class _Tp>
2747struct is_destructible
2748    : public __destructible_false<_Tp, is_function<_Tp>::value> {};
2749
2750template <class _Tp>
2751struct is_destructible<_Tp[]>
2752    : public false_type {};
2753
2754template <>
2755struct is_destructible<void>
2756    : public false_type {};
2757
2758#if _LIBCPP_STD_VER > 14
2759template <class _Tp>
2760inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
2761#endif
2762
2763#endif // __has_keyword(__is_destructible)
2764
2765template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
2766struct __member_pointer_traits_imp
2767{
2768};
2769
2770template <class _Rp, class _Class, class ..._Param>
2771struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
2772{
2773    typedef _Class _ClassType;
2774    typedef _Rp _ReturnType;
2775    typedef _Rp (_FnType) (_Param...);
2776};
2777
2778template <class _Rp, class _Class, class ..._Param>
2779struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
2780{
2781    typedef _Class _ClassType;
2782    typedef _Rp _ReturnType;
2783    typedef _Rp (_FnType) (_Param..., ...);
2784};
2785
2786template <class _Rp, class _Class, class ..._Param>
2787struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
2788{
2789    typedef _Class const _ClassType;
2790    typedef _Rp _ReturnType;
2791    typedef _Rp (_FnType) (_Param...);
2792};
2793
2794template <class _Rp, class _Class, class ..._Param>
2795struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
2796{
2797    typedef _Class const _ClassType;
2798    typedef _Rp _ReturnType;
2799    typedef _Rp (_FnType) (_Param..., ...);
2800};
2801
2802template <class _Rp, class _Class, class ..._Param>
2803struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
2804{
2805    typedef _Class volatile _ClassType;
2806    typedef _Rp _ReturnType;
2807    typedef _Rp (_FnType) (_Param...);
2808};
2809
2810template <class _Rp, class _Class, class ..._Param>
2811struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
2812{
2813    typedef _Class volatile _ClassType;
2814    typedef _Rp _ReturnType;
2815    typedef _Rp (_FnType) (_Param..., ...);
2816};
2817
2818template <class _Rp, class _Class, class ..._Param>
2819struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
2820{
2821    typedef _Class const volatile _ClassType;
2822    typedef _Rp _ReturnType;
2823    typedef _Rp (_FnType) (_Param...);
2824};
2825
2826template <class _Rp, class _Class, class ..._Param>
2827struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
2828{
2829    typedef _Class const volatile _ClassType;
2830    typedef _Rp _ReturnType;
2831    typedef _Rp (_FnType) (_Param..., ...);
2832};
2833
2834#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2835
2836template <class _Rp, class _Class, class ..._Param>
2837struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
2838{
2839    typedef _Class& _ClassType;
2840    typedef _Rp _ReturnType;
2841    typedef _Rp (_FnType) (_Param...);
2842};
2843
2844template <class _Rp, class _Class, class ..._Param>
2845struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
2846{
2847    typedef _Class& _ClassType;
2848    typedef _Rp _ReturnType;
2849    typedef _Rp (_FnType) (_Param..., ...);
2850};
2851
2852template <class _Rp, class _Class, class ..._Param>
2853struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
2854{
2855    typedef _Class const& _ClassType;
2856    typedef _Rp _ReturnType;
2857    typedef _Rp (_FnType) (_Param...);
2858};
2859
2860template <class _Rp, class _Class, class ..._Param>
2861struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
2862{
2863    typedef _Class const& _ClassType;
2864    typedef _Rp _ReturnType;
2865    typedef _Rp (_FnType) (_Param..., ...);
2866};
2867
2868template <class _Rp, class _Class, class ..._Param>
2869struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
2870{
2871    typedef _Class volatile& _ClassType;
2872    typedef _Rp _ReturnType;
2873    typedef _Rp (_FnType) (_Param...);
2874};
2875
2876template <class _Rp, class _Class, class ..._Param>
2877struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
2878{
2879    typedef _Class volatile& _ClassType;
2880    typedef _Rp _ReturnType;
2881    typedef _Rp (_FnType) (_Param..., ...);
2882};
2883
2884template <class _Rp, class _Class, class ..._Param>
2885struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
2886{
2887    typedef _Class const volatile& _ClassType;
2888    typedef _Rp _ReturnType;
2889    typedef _Rp (_FnType) (_Param...);
2890};
2891
2892template <class _Rp, class _Class, class ..._Param>
2893struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
2894{
2895    typedef _Class const volatile& _ClassType;
2896    typedef _Rp _ReturnType;
2897    typedef _Rp (_FnType) (_Param..., ...);
2898};
2899
2900template <class _Rp, class _Class, class ..._Param>
2901struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
2902{
2903    typedef _Class&& _ClassType;
2904    typedef _Rp _ReturnType;
2905    typedef _Rp (_FnType) (_Param...);
2906};
2907
2908template <class _Rp, class _Class, class ..._Param>
2909struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
2910{
2911    typedef _Class&& _ClassType;
2912    typedef _Rp _ReturnType;
2913    typedef _Rp (_FnType) (_Param..., ...);
2914};
2915
2916template <class _Rp, class _Class, class ..._Param>
2917struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
2918{
2919    typedef _Class const&& _ClassType;
2920    typedef _Rp _ReturnType;
2921    typedef _Rp (_FnType) (_Param...);
2922};
2923
2924template <class _Rp, class _Class, class ..._Param>
2925struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
2926{
2927    typedef _Class const&& _ClassType;
2928    typedef _Rp _ReturnType;
2929    typedef _Rp (_FnType) (_Param..., ...);
2930};
2931
2932template <class _Rp, class _Class, class ..._Param>
2933struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
2934{
2935    typedef _Class volatile&& _ClassType;
2936    typedef _Rp _ReturnType;
2937    typedef _Rp (_FnType) (_Param...);
2938};
2939
2940template <class _Rp, class _Class, class ..._Param>
2941struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
2942{
2943    typedef _Class volatile&& _ClassType;
2944    typedef _Rp _ReturnType;
2945    typedef _Rp (_FnType) (_Param..., ...);
2946};
2947
2948template <class _Rp, class _Class, class ..._Param>
2949struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
2950{
2951    typedef _Class const volatile&& _ClassType;
2952    typedef _Rp _ReturnType;
2953    typedef _Rp (_FnType) (_Param...);
2954};
2955
2956template <class _Rp, class _Class, class ..._Param>
2957struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
2958{
2959    typedef _Class const volatile&& _ClassType;
2960    typedef _Rp _ReturnType;
2961    typedef _Rp (_FnType) (_Param..., ...);
2962};
2963
2964#endif // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
2965
2966
2967template <class _Rp, class _Class>
2968struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
2969{
2970    typedef _Class _ClassType;
2971    typedef _Rp _ReturnType;
2972};
2973
2974template <class _MP>
2975struct __member_pointer_traits
2976    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
2977                    is_member_function_pointer<_MP>::value,
2978                    is_member_object_pointer<_MP>::value>
2979{
2980//     typedef ... _ClassType;
2981//     typedef ... _ReturnType;
2982//     typedef ... _FnType;
2983};
2984
2985
2986template <class _DecayedFp>
2987struct __member_pointer_class_type {};
2988
2989template <class _Ret, class _ClassType>
2990struct __member_pointer_class_type<_Ret _ClassType::*> {
2991  typedef _ClassType type;
2992};
2993
2994// template <class T, class... Args> struct is_constructible;
2995
2996template <class _Tp, class ..._Args>
2997struct _LIBCPP_TEMPLATE_VIS is_constructible
2998    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
2999{ };
3000
3001#if _LIBCPP_STD_VER > 14
3002template <class _Tp, class ..._Args>
3003inline constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
3004#endif
3005
3006// is_default_constructible
3007
3008template <class _Tp>
3009struct _LIBCPP_TEMPLATE_VIS is_default_constructible
3010    : public is_constructible<_Tp>
3011    {};
3012
3013#if _LIBCPP_STD_VER > 14
3014template <class _Tp>
3015inline constexpr bool is_default_constructible_v = is_default_constructible<_Tp>::value;
3016#endif
3017
3018#ifndef _LIBCPP_CXX03_LANG
3019// First of all, we can't implement this check in C++03 mode because the {}
3020// default initialization syntax isn't valid.
3021// Second, we implement the trait in a funny manner with two defaulted template
3022// arguments to workaround Clang's PR43454.
3023template <class _Tp>
3024void __test_implicit_default_constructible(_Tp);
3025
3026template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type>
3027struct __is_implicitly_default_constructible
3028    : false_type
3029{ };
3030
3031template <class _Tp>
3032struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true_type>
3033    : true_type
3034{ };
3035
3036template <class _Tp>
3037struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false_type>
3038    : false_type
3039{ };
3040#endif // !C++03
3041
3042// is_copy_constructible
3043
3044template <class _Tp>
3045struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
3046    : public is_constructible<_Tp,
3047                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3048
3049#if _LIBCPP_STD_VER > 14
3050template <class _Tp>
3051inline constexpr bool is_copy_constructible_v = is_copy_constructible<_Tp>::value;
3052#endif
3053
3054// is_move_constructible
3055
3056template <class _Tp>
3057struct _LIBCPP_TEMPLATE_VIS is_move_constructible
3058    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3059    {};
3060
3061#if _LIBCPP_STD_VER > 14
3062template <class _Tp>
3063inline constexpr bool is_move_constructible_v = is_move_constructible<_Tp>::value;
3064#endif
3065
3066// is_trivially_constructible
3067
3068template <class _Tp, class... _Args>
3069struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
3070    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
3071{
3072};
3073
3074#if _LIBCPP_STD_VER > 14
3075template <class _Tp, class... _Args>
3076inline constexpr bool is_trivially_constructible_v = is_trivially_constructible<_Tp, _Args...>::value;
3077#endif
3078
3079// is_trivially_default_constructible
3080
3081template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
3082    : public is_trivially_constructible<_Tp>
3083    {};
3084
3085#if _LIBCPP_STD_VER > 14
3086template <class _Tp>
3087inline constexpr bool is_trivially_default_constructible_v = is_trivially_default_constructible<_Tp>::value;
3088#endif
3089
3090// is_trivially_copy_constructible
3091
3092template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
3093    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
3094    {};
3095
3096#if _LIBCPP_STD_VER > 14
3097template <class _Tp>
3098inline constexpr bool is_trivially_copy_constructible_v = is_trivially_copy_constructible<_Tp>::value;
3099#endif
3100
3101// is_trivially_move_constructible
3102
3103template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
3104    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3105    {};
3106
3107#if _LIBCPP_STD_VER > 14
3108template <class _Tp>
3109inline constexpr bool is_trivially_move_constructible_v = is_trivially_move_constructible<_Tp>::value;
3110#endif
3111
3112// is_trivially_assignable
3113
3114template <class _Tp, class _Arg>
3115struct is_trivially_assignable
3116    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
3117{ };
3118
3119#if _LIBCPP_STD_VER > 14
3120template <class _Tp, class _Arg>
3121inline constexpr bool is_trivially_assignable_v = is_trivially_assignable<_Tp, _Arg>::value;
3122#endif
3123
3124// is_trivially_copy_assignable
3125
3126template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
3127    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3128                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3129
3130#if _LIBCPP_STD_VER > 14
3131template <class _Tp>
3132inline constexpr bool is_trivially_copy_assignable_v = is_trivially_copy_assignable<_Tp>::value;
3133#endif
3134
3135// is_trivially_move_assignable
3136
3137template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
3138    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
3139                                     typename add_rvalue_reference<_Tp>::type>
3140    {};
3141
3142#if _LIBCPP_STD_VER > 14
3143template <class _Tp>
3144inline constexpr bool is_trivially_move_assignable_v = is_trivially_move_assignable<_Tp>::value;
3145#endif
3146
3147// is_trivially_destructible
3148
3149#if __has_keyword(__is_trivially_destructible)
3150
3151template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3152    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
3153
3154#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
3155
3156template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3157    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
3158
3159#else
3160
3161template <class _Tp> struct __libcpp_trivial_destructor
3162    : public integral_constant<bool, is_scalar<_Tp>::value ||
3163                                     is_reference<_Tp>::value> {};
3164
3165template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
3166    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
3167
3168template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
3169    : public false_type {};
3170
3171#endif
3172
3173#if _LIBCPP_STD_VER > 14
3174template <class _Tp>
3175inline constexpr bool is_trivially_destructible_v = is_trivially_destructible<_Tp>::value;
3176#endif
3177
3178// is_nothrow_constructible
3179
3180#if __has_keyword(__is_nothrow_constructible)
3181
3182template <class _Tp, class... _Args>
3183struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3184    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
3185
3186#else
3187
3188template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
3189
3190template <class _Tp, class... _Args>
3191struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
3192    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
3193{
3194};
3195
3196template <class _Tp>
3197void __implicit_conversion_to(_Tp) noexcept { }
3198
3199template <class _Tp, class _Arg>
3200struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
3201    : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(declval<_Arg>()))>
3202{
3203};
3204
3205template <class _Tp, bool _IsReference, class... _Args>
3206struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
3207    : public false_type
3208{
3209};
3210
3211template <class _Tp, class... _Args>
3212struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
3213    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
3214{
3215};
3216
3217template <class _Tp, size_t _Ns>
3218struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
3219    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
3220{
3221};
3222
3223#endif // _LIBCPP_HAS_NO_NOEXCEPT
3224
3225
3226#if _LIBCPP_STD_VER > 14
3227template <class _Tp, class ..._Args>
3228inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
3229#endif
3230
3231// is_nothrow_default_constructible
3232
3233template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
3234    : public is_nothrow_constructible<_Tp>
3235    {};
3236
3237#if _LIBCPP_STD_VER > 14
3238template <class _Tp>
3239inline constexpr bool is_nothrow_default_constructible_v = is_nothrow_default_constructible<_Tp>::value;
3240#endif
3241
3242// is_nothrow_copy_constructible
3243
3244template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
3245    : public is_nothrow_constructible<_Tp,
3246                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3247
3248#if _LIBCPP_STD_VER > 14
3249template <class _Tp>
3250inline constexpr bool is_nothrow_copy_constructible_v = is_nothrow_copy_constructible<_Tp>::value;
3251#endif
3252
3253// is_nothrow_move_constructible
3254
3255template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
3256    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
3257    {};
3258
3259#if _LIBCPP_STD_VER > 14
3260template <class _Tp>
3261inline constexpr bool is_nothrow_move_constructible_v = is_nothrow_move_constructible<_Tp>::value;
3262#endif
3263
3264// is_nothrow_assignable
3265
3266#if __has_keyword(__is_nothrow_assignable)
3267
3268template <class _Tp, class _Arg>
3269struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3270    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
3271
3272#else
3273
3274template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
3275
3276template <class _Tp, class _Arg>
3277struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
3278    : public false_type
3279{
3280};
3281
3282template <class _Tp, class _Arg>
3283struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
3284    : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Arg>()) >
3285{
3286};
3287
3288template <class _Tp, class _Arg>
3289struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
3290    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
3291{
3292};
3293
3294#endif // _LIBCPP_HAS_NO_NOEXCEPT
3295
3296#if _LIBCPP_STD_VER > 14
3297template <class _Tp, class _Arg>
3298inline constexpr bool is_nothrow_assignable_v = is_nothrow_assignable<_Tp, _Arg>::value;
3299#endif
3300
3301// is_nothrow_copy_assignable
3302
3303template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
3304    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3305                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
3306
3307#if _LIBCPP_STD_VER > 14
3308template <class _Tp>
3309inline constexpr bool is_nothrow_copy_assignable_v = is_nothrow_copy_assignable<_Tp>::value;
3310#endif
3311
3312// is_nothrow_move_assignable
3313
3314template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
3315    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
3316                                     typename add_rvalue_reference<_Tp>::type>
3317    {};
3318
3319#if _LIBCPP_STD_VER > 14
3320template <class _Tp>
3321inline constexpr bool is_nothrow_move_assignable_v = is_nothrow_move_assignable<_Tp>::value;
3322#endif
3323
3324// is_nothrow_destructible
3325
3326#if !defined(_LIBCPP_CXX03_LANG)
3327
3328template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
3329
3330template <class _Tp>
3331struct __libcpp_is_nothrow_destructible<false, _Tp>
3332    : public false_type
3333{
3334};
3335
3336template <class _Tp>
3337struct __libcpp_is_nothrow_destructible<true, _Tp>
3338    : public integral_constant<bool, noexcept(declval<_Tp>().~_Tp()) >
3339{
3340};
3341
3342template <class _Tp>
3343struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3344    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
3345{
3346};
3347
3348template <class _Tp, size_t _Ns>
3349struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
3350    : public is_nothrow_destructible<_Tp>
3351{
3352};
3353
3354template <class _Tp>
3355struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
3356    : public true_type
3357{
3358};
3359
3360template <class _Tp>
3361struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
3362    : public true_type
3363{
3364};
3365
3366#else
3367
3368template <class _Tp> struct __libcpp_nothrow_destructor
3369    : public integral_constant<bool, is_scalar<_Tp>::value ||
3370                                     is_reference<_Tp>::value> {};
3371
3372template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
3373    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
3374
3375template <class _Tp>
3376struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
3377    : public false_type {};
3378
3379#endif
3380
3381#if _LIBCPP_STD_VER > 14
3382template <class _Tp>
3383inline constexpr bool is_nothrow_destructible_v = is_nothrow_destructible<_Tp>::value;
3384#endif
3385
3386// is_pod
3387
3388#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
3389
3390template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3391    : public integral_constant<bool, __is_pod(_Tp)> {};
3392
3393#else
3394
3395template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
3396    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
3397                                     is_trivially_copy_constructible<_Tp>::value      &&
3398                                     is_trivially_copy_assignable<_Tp>::value    &&
3399                                     is_trivially_destructible<_Tp>::value> {};
3400
3401#endif
3402
3403#if _LIBCPP_STD_VER > 14
3404template <class _Tp>
3405inline constexpr bool is_pod_v = is_pod<_Tp>::value;
3406#endif
3407
3408// is_literal_type;
3409
3410#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3411template <class _Tp> struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 is_literal_type
3412    : public integral_constant<bool, __is_literal_type(_Tp)>
3413    {};
3414
3415#if _LIBCPP_STD_VER > 14
3416template <class _Tp>
3417_LIBCPP_DEPRECATED_IN_CXX17 inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
3418#endif // _LIBCPP_STD_VER > 14
3419#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3420
3421// is_standard_layout;
3422
3423template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
3424#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
3425    : public integral_constant<bool, __is_standard_layout(_Tp)>
3426#else
3427    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
3428#endif
3429    {};
3430
3431#if _LIBCPP_STD_VER > 14
3432template <class _Tp>
3433inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
3434#endif
3435
3436// is_trivially_copyable;
3437
3438template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
3439    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
3440    {};
3441
3442#if _LIBCPP_STD_VER > 14
3443template <class _Tp>
3444inline constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
3445#endif
3446
3447// is_trivial;
3448
3449template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
3450#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
3451    : public integral_constant<bool, __is_trivial(_Tp)>
3452#else
3453    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
3454                                 is_trivially_default_constructible<_Tp>::value>
3455#endif
3456    {};
3457
3458#if _LIBCPP_STD_VER > 14
3459template <class _Tp>
3460inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
3461#endif
3462
3463template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
3464template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
3465template <class _Tp> struct __is_reference_wrapper
3466    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
3467
3468#ifndef _LIBCPP_CXX03_LANG
3469
3470template <class _Fp, class _A0,
3471         class _DecayFp = typename decay<_Fp>::type,
3472         class _DecayA0 = typename decay<_A0>::type,
3473         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3474using __enable_if_bullet1 = typename enable_if
3475    <
3476        is_member_function_pointer<_DecayFp>::value
3477        && is_base_of<_ClassT, _DecayA0>::value
3478    >::type;
3479
3480template <class _Fp, class _A0,
3481         class _DecayFp = typename decay<_Fp>::type,
3482         class _DecayA0 = typename decay<_A0>::type>
3483using __enable_if_bullet2 = typename enable_if
3484    <
3485        is_member_function_pointer<_DecayFp>::value
3486        && __is_reference_wrapper<_DecayA0>::value
3487    >::type;
3488
3489template <class _Fp, class _A0,
3490         class _DecayFp = typename decay<_Fp>::type,
3491         class _DecayA0 = typename decay<_A0>::type,
3492         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3493using __enable_if_bullet3 = typename enable_if
3494    <
3495        is_member_function_pointer<_DecayFp>::value
3496        && !is_base_of<_ClassT, _DecayA0>::value
3497        && !__is_reference_wrapper<_DecayA0>::value
3498    >::type;
3499
3500template <class _Fp, class _A0,
3501         class _DecayFp = typename decay<_Fp>::type,
3502         class _DecayA0 = typename decay<_A0>::type,
3503         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3504using __enable_if_bullet4 = typename enable_if
3505    <
3506        is_member_object_pointer<_DecayFp>::value
3507        && is_base_of<_ClassT, _DecayA0>::value
3508    >::type;
3509
3510template <class _Fp, class _A0,
3511         class _DecayFp = typename decay<_Fp>::type,
3512         class _DecayA0 = typename decay<_A0>::type>
3513using __enable_if_bullet5 = typename enable_if
3514    <
3515        is_member_object_pointer<_DecayFp>::value
3516        && __is_reference_wrapper<_DecayA0>::value
3517    >::type;
3518
3519template <class _Fp, class _A0,
3520         class _DecayFp = typename decay<_Fp>::type,
3521         class _DecayA0 = typename decay<_A0>::type,
3522         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
3523using __enable_if_bullet6 = typename enable_if
3524    <
3525        is_member_object_pointer<_DecayFp>::value
3526        && !is_base_of<_ClassT, _DecayA0>::value
3527        && !__is_reference_wrapper<_DecayA0>::value
3528    >::type;
3529
3530// __invoke forward declarations
3531
3532// fall back - none of the bullets
3533
3534template <class ..._Args>
3535auto __invoke(__any, _Args&& ...__args) -> __nat;
3536
3537template <class ..._Args>
3538auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
3539
3540// bullets 1, 2 and 3
3541
3542template <class _Fp, class _A0, class ..._Args,
3543          class = __enable_if_bullet1<_Fp, _A0>>
3544inline _LIBCPP_INLINE_VISIBILITY
3545_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3546__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3547    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
3548    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
3549    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
3550
3551template <class _Fp, class _A0, class ..._Args,
3552          class = __enable_if_bullet1<_Fp, _A0>>
3553inline _LIBCPP_INLINE_VISIBILITY
3554_LIBCPP_CONSTEXPR auto
3555__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3556    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
3557    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
3558    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
3559
3560template <class _Fp, class _A0, class ..._Args,
3561          class = __enable_if_bullet2<_Fp, _A0>>
3562inline _LIBCPP_INLINE_VISIBILITY
3563_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3564__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3565    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
3566    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
3567    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
3568
3569template <class _Fp, class _A0, class ..._Args,
3570          class = __enable_if_bullet2<_Fp, _A0>>
3571inline _LIBCPP_INLINE_VISIBILITY
3572_LIBCPP_CONSTEXPR auto
3573__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3574    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
3575    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
3576    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
3577
3578template <class _Fp, class _A0, class ..._Args,
3579          class = __enable_if_bullet3<_Fp, _A0>>
3580inline _LIBCPP_INLINE_VISIBILITY
3581_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3582__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3583    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
3584    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
3585    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
3586
3587template <class _Fp, class _A0, class ..._Args,
3588          class = __enable_if_bullet3<_Fp, _A0>>
3589inline _LIBCPP_INLINE_VISIBILITY
3590_LIBCPP_CONSTEXPR auto
3591__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
3592    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
3593    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
3594    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
3595
3596// bullets 4, 5 and 6
3597
3598template <class _Fp, class _A0,
3599          class = __enable_if_bullet4<_Fp, _A0>>
3600inline _LIBCPP_INLINE_VISIBILITY
3601_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3602__invoke(_Fp&& __f, _A0&& __a0)
3603    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
3604    -> decltype(      static_cast<_A0&&>(__a0).*__f)
3605    { return          static_cast<_A0&&>(__a0).*__f; }
3606
3607template <class _Fp, class _A0,
3608          class = __enable_if_bullet4<_Fp, _A0>>
3609inline _LIBCPP_INLINE_VISIBILITY
3610_LIBCPP_CONSTEXPR auto
3611__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3612    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
3613    -> decltype(      static_cast<_A0&&>(__a0).*__f)
3614    { return          static_cast<_A0&&>(__a0).*__f; }
3615
3616template <class _Fp, class _A0,
3617          class = __enable_if_bullet5<_Fp, _A0>>
3618inline _LIBCPP_INLINE_VISIBILITY
3619_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3620__invoke(_Fp&& __f, _A0&& __a0)
3621    noexcept(noexcept(__a0.get().*__f))
3622    -> decltype(      __a0.get().*__f)
3623    { return          __a0.get().*__f; }
3624
3625template <class _Fp, class _A0,
3626          class = __enable_if_bullet5<_Fp, _A0>>
3627inline _LIBCPP_INLINE_VISIBILITY
3628_LIBCPP_CONSTEXPR auto
3629__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3630    noexcept(noexcept(__a0.get().*__f))
3631    -> decltype(      __a0.get().*__f)
3632    { return          __a0.get().*__f; }
3633
3634template <class _Fp, class _A0,
3635          class = __enable_if_bullet6<_Fp, _A0>>
3636inline _LIBCPP_INLINE_VISIBILITY
3637_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3638__invoke(_Fp&& __f, _A0&& __a0)
3639    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
3640    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
3641    { return          (*static_cast<_A0&&>(__a0)).*__f; }
3642
3643template <class _Fp, class _A0,
3644          class = __enable_if_bullet6<_Fp, _A0>>
3645inline _LIBCPP_INLINE_VISIBILITY
3646_LIBCPP_CONSTEXPR auto
3647__invoke_constexpr(_Fp&& __f, _A0&& __a0)
3648    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
3649    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
3650    { return          (*static_cast<_A0&&>(__a0)).*__f; }
3651
3652// bullet 7
3653
3654template <class _Fp, class ..._Args>
3655inline _LIBCPP_INLINE_VISIBILITY
3656_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
3657__invoke(_Fp&& __f, _Args&& ...__args)
3658    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
3659    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
3660    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
3661
3662template <class _Fp, class ..._Args>
3663inline _LIBCPP_INLINE_VISIBILITY
3664_LIBCPP_CONSTEXPR auto
3665__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
3666    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
3667    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
3668    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
3669
3670// __invokable
3671template <class _Ret, class _Fp, class ..._Args>
3672struct __invokable_r
3673{
3674  template <class _XFp, class ..._XArgs>
3675  static auto __try_call(int) -> decltype(
3676    _VSTD::__invoke(declval<_XFp>(), declval<_XArgs>()...));
3677  template <class _XFp, class ..._XArgs>
3678  static __nat __try_call(...);
3679
3680  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
3681  // or incomplete array types as required by the standard.
3682  using _Result = decltype(__try_call<_Fp, _Args...>(0));
3683
3684  using type =
3685  typename conditional<
3686      _IsNotSame<_Result, __nat>::value,
3687      typename conditional<
3688          is_void<_Ret>::value,
3689          true_type,
3690          is_convertible<_Result, _Ret>
3691      >::type,
3692      false_type
3693  >::type;
3694  static const bool value = type::value;
3695};
3696template <class _Fp, class ..._Args>
3697using __invokable = __invokable_r<void, _Fp, _Args...>;
3698
3699template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
3700struct __nothrow_invokable_r_imp {
3701  static const bool value = false;
3702};
3703
3704template <class _Ret, class _Fp, class ..._Args>
3705struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
3706{
3707    typedef __nothrow_invokable_r_imp _ThisT;
3708
3709    template <class _Tp>
3710    static void __test_noexcept(_Tp) noexcept;
3711
3712    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
3713        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...)));
3714};
3715
3716template <class _Ret, class _Fp, class ..._Args>
3717struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
3718{
3719    static const bool value = noexcept(
3720        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...));
3721};
3722
3723template <class _Ret, class _Fp, class ..._Args>
3724using __nothrow_invokable_r =
3725    __nothrow_invokable_r_imp<
3726            __invokable_r<_Ret, _Fp, _Args...>::value,
3727            is_void<_Ret>::value,
3728            _Ret, _Fp, _Args...
3729    >;
3730
3731template <class _Fp, class ..._Args>
3732using __nothrow_invokable =
3733    __nothrow_invokable_r_imp<
3734            __invokable<_Fp, _Args...>::value,
3735            true, void, _Fp, _Args...
3736    >;
3737
3738template <class _Fp, class ..._Args>
3739struct __invoke_of
3740    : public enable_if<
3741        __invokable<_Fp, _Args...>::value,
3742        typename __invokable_r<void, _Fp, _Args...>::_Result>
3743{
3744};
3745
3746#endif // _LIBCPP_CXX03_LANG
3747
3748// result_of
3749
3750#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3751template <class _Callable> class _LIBCPP_DEPRECATED_IN_CXX17 result_of;
3752
3753#ifndef _LIBCPP_CXX03_LANG
3754
3755template <class _Fp, class ..._Args>
3756class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
3757    : public __invoke_of<_Fp, _Args...>
3758{
3759};
3760
3761#else // C++03
3762
3763template <class _Fn, bool, bool>
3764class __result_of
3765{
3766};
3767
3768template <class _Fn, class ..._Args>
3769class __result_of<_Fn(_Args...), true, false>
3770{
3771public:
3772    typedef decltype(declval<_Fn>()(declval<_Args>()...)) type;
3773};
3774
3775template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
3776struct __result_of_mp;
3777
3778// member function pointer
3779
3780template <class _MP, class _Tp>
3781struct __result_of_mp<_MP, _Tp, true>
3782{
3783    using type = typename __member_pointer_traits<_MP>::_ReturnType;
3784};
3785
3786// member data pointer
3787
3788template <class _MP, class _Tp, bool>
3789struct __result_of_mdp;
3790
3791template <class _Rp, class _Class, class _Tp>
3792struct __result_of_mdp<_Rp _Class::*, _Tp, false>
3793{
3794    using type = typename __apply_cv<decltype(*declval<_Tp>()), _Rp>::type&;
3795};
3796
3797template <class _Rp, class _Class, class _Tp>
3798struct __result_of_mdp<_Rp _Class::*, _Tp, true>
3799{
3800    using type = typename __apply_cv<_Tp, _Rp>::type&;
3801};
3802
3803template <class _Rp, class _Class, class _Tp>
3804struct __result_of_mp<_Rp _Class::*, _Tp, false>
3805    : public __result_of_mdp<_Rp _Class::*, _Tp,
3806            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
3807{
3808};
3809
3810template <class _Fn, class _Tp>
3811class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
3812    : public __result_of_mp<typename remove_reference<_Fn>::type,
3813                            _Tp,
3814                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3815{
3816};
3817
3818template <class _Fn, class _Tp, class ..._Args>
3819class __result_of<_Fn(_Tp, _Args...), false, true>  // _Fn must be member pointer
3820    : public __result_of_mp<typename remove_reference<_Fn>::type,
3821                            _Tp,
3822                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
3823{
3824};
3825
3826template <class _Fn, class ..._Args>
3827class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_Args...)>
3828    : public __result_of<_Fn(_Args...),
3829                         is_class<typename remove_reference<_Fn>::type>::value ||
3830                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
3831                         is_member_pointer<typename remove_reference<_Fn>::type>::value
3832                        >
3833{
3834};
3835
3836#endif // C++03
3837
3838#if _LIBCPP_STD_VER > 11
3839template <class _Tp> using result_of_t _LIBCPP_DEPRECATED_IN_CXX17 = typename result_of<_Tp>::type;
3840#endif // _LIBCPP_STD_VER > 11
3841#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
3842
3843#if _LIBCPP_STD_VER > 14
3844
3845// invoke_result
3846
3847template <class _Fn, class... _Args>
3848struct _LIBCPP_TEMPLATE_VIS invoke_result
3849    : __invoke_of<_Fn, _Args...>
3850{
3851};
3852
3853template <class _Fn, class... _Args>
3854using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
3855
3856// is_invocable
3857
3858template <class _Fn, class ..._Args>
3859struct _LIBCPP_TEMPLATE_VIS is_invocable
3860    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
3861
3862template <class _Ret, class _Fn, class ..._Args>
3863struct _LIBCPP_TEMPLATE_VIS is_invocable_r
3864    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
3865
3866template <class _Fn, class ..._Args>
3867inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
3868
3869template <class _Ret, class _Fn, class ..._Args>
3870inline constexpr bool is_invocable_r_v = is_invocable_r<_Ret, _Fn, _Args...>::value;
3871
3872// is_nothrow_invocable
3873
3874template <class _Fn, class ..._Args>
3875struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
3876    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
3877
3878template <class _Ret, class _Fn, class ..._Args>
3879struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
3880    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
3881
3882template <class _Fn, class ..._Args>
3883inline constexpr bool is_nothrow_invocable_v = is_nothrow_invocable<_Fn, _Args...>::value;
3884
3885template <class _Ret, class _Fn, class ..._Args>
3886inline constexpr bool is_nothrow_invocable_r_v = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
3887
3888#endif // _LIBCPP_STD_VER > 14
3889
3890// __swappable
3891
3892template <class _Tp> struct __is_swappable;
3893template <class _Tp> struct __is_nothrow_swappable;
3894
3895
3896#ifndef _LIBCPP_CXX03_LANG
3897template <class _Tp>
3898using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
3899#else
3900template <class>
3901using __swap_result_t = void;
3902#endif
3903
3904template <class _Tp>
3905inline _LIBCPP_INLINE_VISIBILITY
3906_LIBCPP_CONSTEXPR_AFTER_CXX17 __swap_result_t<_Tp>
3907swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
3908                                    is_nothrow_move_assignable<_Tp>::value);
3909
3910template<class _Tp, size_t _Np>
3911inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
3912typename enable_if<
3913    __is_swappable<_Tp>::value
3914>::type
3915swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
3916
3917namespace __detail
3918{
3919// ALL generic swap overloads MUST already have a declaration available at this point.
3920
3921template <class _Tp, class _Up = _Tp,
3922          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
3923struct __swappable_with
3924{
3925    template <class _LHS, class _RHS>
3926    static decltype(swap(declval<_LHS>(), declval<_RHS>()))
3927    __test_swap(int);
3928    template <class, class>
3929    static __nat __test_swap(long);
3930
3931    // Extra parens are needed for the C++03 definition of decltype.
3932    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
3933    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
3934
3935    static const bool value = _IsNotSame<__swap1, __nat>::value
3936                           && _IsNotSame<__swap2, __nat>::value;
3937};
3938
3939template <class _Tp, class _Up>
3940struct __swappable_with<_Tp, _Up,  false> : false_type {};
3941
3942template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
3943struct __nothrow_swappable_with {
3944  static const bool value =
3945#ifndef _LIBCPP_HAS_NO_NOEXCEPT
3946      noexcept(swap(declval<_Tp>(), declval<_Up>()))
3947  &&  noexcept(swap(declval<_Up>(), declval<_Tp>()));
3948#else
3949      false;
3950#endif
3951};
3952
3953template <class _Tp, class _Up>
3954struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
3955
3956} // namespace __detail
3957
3958template <class _Tp>
3959struct __is_swappable
3960    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
3961{
3962};
3963
3964template <class _Tp>
3965struct __is_nothrow_swappable
3966    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
3967{
3968};
3969
3970#if _LIBCPP_STD_VER > 14
3971
3972template <class _Tp, class _Up>
3973struct _LIBCPP_TEMPLATE_VIS is_swappable_with
3974    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
3975{
3976};
3977
3978template <class _Tp>
3979struct _LIBCPP_TEMPLATE_VIS is_swappable
3980    : public conditional<
3981        __is_referenceable<_Tp>::value,
3982        is_swappable_with<
3983            typename add_lvalue_reference<_Tp>::type,
3984            typename add_lvalue_reference<_Tp>::type>,
3985        false_type
3986    >::type
3987{
3988};
3989
3990template <class _Tp, class _Up>
3991struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
3992    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
3993{
3994};
3995
3996template <class _Tp>
3997struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
3998    : public conditional<
3999        __is_referenceable<_Tp>::value,
4000        is_nothrow_swappable_with<
4001            typename add_lvalue_reference<_Tp>::type,
4002            typename add_lvalue_reference<_Tp>::type>,
4003        false_type
4004    >::type
4005{
4006};
4007
4008template <class _Tp, class _Up>
4009inline constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
4010
4011template <class _Tp>
4012inline constexpr bool is_swappable_v = is_swappable<_Tp>::value;
4013
4014template <class _Tp, class _Up>
4015inline constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<_Tp, _Up>::value;
4016
4017template <class _Tp>
4018inline constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<_Tp>::value;
4019
4020#endif // _LIBCPP_STD_VER > 14
4021
4022template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
4023
4024template <class _Tp>
4025struct __underlying_type_impl<_Tp, false> {};
4026
4027template <class _Tp>
4028struct __underlying_type_impl<_Tp, true>
4029{
4030    typedef __underlying_type(_Tp) type;
4031};
4032
4033template <class _Tp>
4034struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
4035
4036#if _LIBCPP_STD_VER > 11
4037template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
4038#endif
4039
4040template <class _Tp, bool = is_enum<_Tp>::value>
4041struct __sfinae_underlying_type
4042{
4043    typedef typename underlying_type<_Tp>::type type;
4044    typedef decltype(((type)1) + 0) __promoted_type;
4045};
4046
4047template <class _Tp>
4048struct __sfinae_underlying_type<_Tp, false> {};
4049
4050inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4051int __convert_to_integral(int __val) { return __val; }
4052
4053inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4054unsigned __convert_to_integral(unsigned __val) { return __val; }
4055
4056inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4057long __convert_to_integral(long __val) { return __val; }
4058
4059inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4060unsigned long __convert_to_integral(unsigned long __val) { return __val; }
4061
4062inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4063long long __convert_to_integral(long long __val) { return __val; }
4064
4065inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4066unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
4067
4068template<typename _Fp>
4069inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4070typename enable_if<is_floating_point<_Fp>::value, long long>::type
4071 __convert_to_integral(_Fp __val) { return __val; }
4072
4073#ifndef _LIBCPP_HAS_NO_INT128
4074inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4075__int128_t __convert_to_integral(__int128_t __val) { return __val; }
4076
4077inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4078__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
4079#endif
4080
4081template <class _Tp>
4082inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
4083typename __sfinae_underlying_type<_Tp>::__promoted_type
4084__convert_to_integral(_Tp __val) { return __val; }
4085
4086// is_scoped_enum [meta.unary.prop]
4087
4088#if _LIBCPP_STD_VER > 20
4089template <class _Tp, bool = is_enum_v<_Tp> >
4090struct __is_scoped_enum_helper : false_type {};
4091
4092template <class _Tp>
4093struct __is_scoped_enum_helper<_Tp, true>
4094    : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
4095
4096template <class _Tp>
4097struct _LIBCPP_TEMPLATE_VIS is_scoped_enum
4098    : public __is_scoped_enum_helper<_Tp> {};
4099
4100template <class _Tp>
4101inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
4102#endif
4103
4104#if _LIBCPP_STD_VER > 14
4105
4106template <class... _Args>
4107struct conjunction : _And<_Args...> {};
4108template<class... _Args>
4109inline constexpr bool conjunction_v = conjunction<_Args...>::value;
4110
4111template <class... _Args>
4112struct disjunction : _Or<_Args...> {};
4113template<class... _Args>
4114inline constexpr bool disjunction_v = disjunction<_Args...>::value;
4115
4116template <class _Tp>
4117struct negation : _Not<_Tp> {};
4118template<class _Tp>
4119inline constexpr bool negation_v = negation<_Tp>::value;
4120#endif // _LIBCPP_STD_VER > 14
4121
4122// These traits are used in __tree and __hash_table
4123struct __extract_key_fail_tag {};
4124struct __extract_key_self_tag {};
4125struct __extract_key_first_tag {};
4126
4127template <class _ValTy, class _Key,
4128          class _RawValTy = typename __unconstref<_ValTy>::type>
4129struct __can_extract_key
4130    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
4131                  __extract_key_fail_tag>::type {};
4132
4133template <class _Pair, class _Key, class _First, class _Second>
4134struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
4135    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
4136                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
4137
4138// __can_extract_map_key uses true_type/false_type instead of the tags.
4139// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
4140// and _ValTy == _Key.
4141template <class _ValTy, class _Key, class _ContainerValueTy,
4142          class _RawValTy = typename __unconstref<_ValTy>::type>
4143struct __can_extract_map_key
4144    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
4145
4146// This specialization returns __extract_key_fail_tag for non-map containers
4147// because _Key == _ContainerValueTy
4148template <class _ValTy, class _Key, class _RawValTy>
4149struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
4150    : false_type {};
4151
4152#if _LIBCPP_STD_VER > 17
4153_LIBCPP_INLINE_VISIBILITY
4154inline constexpr bool is_constant_evaluated() noexcept {
4155  return __builtin_is_constant_evaluated();
4156}
4157#endif
4158
4159inline _LIBCPP_CONSTEXPR
4160bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
4161
4162template <class _CharT>
4163using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
4164
4165template<class _Tp>
4166using __make_const_lvalue_ref = const typename remove_reference<_Tp>::type&;
4167
4168#if _LIBCPP_STD_VER > 17
4169template<bool _Const, class _Tp>
4170using __maybe_const = conditional_t<_Const, const _Tp, _Tp>;
4171#endif // _LIBCPP_STD_VER > 17
4172
4173_LIBCPP_END_NAMESPACE_STD
4174
4175#endif // _LIBCPP_TYPE_TRAITS
4176