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1// -*- C++ -*-
2//===------------------------ functional ----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_FUNCTIONAL
12#define _LIBCPP_FUNCTIONAL
13
14/*
15    functional synopsis
16
17namespace std
18{
19
20template <class Arg, class Result>
21struct unary_function
22{
23    typedef Arg    argument_type;
24    typedef Result result_type;
25};
26
27template <class Arg1, class Arg2, class Result>
28struct binary_function
29{
30    typedef Arg1   first_argument_type;
31    typedef Arg2   second_argument_type;
32    typedef Result result_type;
33};
34
35template <class T>
36class reference_wrapper
37    : public unary_function<T1, R> // if wrapping a unary functor
38    : public binary_function<T1, T2, R> // if wraping a binary functor
39{
40public:
41    // types
42    typedef T type;
43    typedef see below result_type; // Not always defined
44
45    // construct/copy/destroy
46    reference_wrapper(T&) noexcept;
47    reference_wrapper(T&&) = delete; // do not bind to temps
48    reference_wrapper(const reference_wrapper<T>& x) noexcept;
49
50    // assignment
51    reference_wrapper& operator=(const reference_wrapper<T>& x) noexcept;
52
53    // access
54    operator T& () const noexcept;
55    T& get() const noexcept;
56
57    // invoke
58    template <class... ArgTypes>
59      typename result_of<T&(ArgTypes&&...)>::type
60          operator() (ArgTypes&&...) const;
61};
62
63template <class T> reference_wrapper<T> ref(T& t) noexcept;
64template <class T> void ref(const T&& t) = delete;
65template <class T> reference_wrapper<T> ref(reference_wrapper<T>t) noexcept;
66
67template <class T> reference_wrapper<const T> cref(const T& t) noexcept;
68template <class T> void cref(const T&& t) = delete;
69template <class T> reference_wrapper<const T> cref(reference_wrapper<T> t) noexcept;
70
71template <class T> struct unwrap_reference;                                       // since C++20
72template <class T> struct unwrap_ref_decay : unwrap_reference<decay_t<T>> { };    // since C++20
73template <class T> using unwrap_reference_t = typename unwrap_reference<T>::type; // since C++20
74template <class T> using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type; // since C++20
75
76template <class T> // <class T=void> in C++14
77struct plus : binary_function<T, T, T>
78{
79    T operator()(const T& x, const T& y) const;
80};
81
82template <class T> // <class T=void> in C++14
83struct minus : binary_function<T, T, T>
84{
85    T operator()(const T& x, const T& y) const;
86};
87
88template <class T> // <class T=void> in C++14
89struct multiplies : binary_function<T, T, T>
90{
91    T operator()(const T& x, const T& y) const;
92};
93
94template <class T> // <class T=void> in C++14
95struct divides : binary_function<T, T, T>
96{
97    T operator()(const T& x, const T& y) const;
98};
99
100template <class T> // <class T=void> in C++14
101struct modulus : binary_function<T, T, T>
102{
103    T operator()(const T& x, const T& y) const;
104};
105
106template <class T> // <class T=void> in C++14
107struct negate : unary_function<T, T>
108{
109    T operator()(const T& x) const;
110};
111
112template <class T> // <class T=void> in C++14
113struct equal_to : binary_function<T, T, bool>
114{
115    bool operator()(const T& x, const T& y) const;
116};
117
118template <class T> // <class T=void> in C++14
119struct not_equal_to : binary_function<T, T, bool>
120{
121    bool operator()(const T& x, const T& y) const;
122};
123
124template <class T> // <class T=void> in C++14
125struct greater : binary_function<T, T, bool>
126{
127    bool operator()(const T& x, const T& y) const;
128};
129
130template <class T> // <class T=void> in C++14
131struct less : binary_function<T, T, bool>
132{
133    bool operator()(const T& x, const T& y) const;
134};
135
136template <class T> // <class T=void> in C++14
137struct greater_equal : binary_function<T, T, bool>
138{
139    bool operator()(const T& x, const T& y) const;
140};
141
142template <class T> // <class T=void> in C++14
143struct less_equal : binary_function<T, T, bool>
144{
145    bool operator()(const T& x, const T& y) const;
146};
147
148template <class T> // <class T=void> in C++14
149struct logical_and : binary_function<T, T, bool>
150{
151    bool operator()(const T& x, const T& y) const;
152};
153
154template <class T> // <class T=void> in C++14
155struct logical_or : binary_function<T, T, bool>
156{
157    bool operator()(const T& x, const T& y) const;
158};
159
160template <class T> // <class T=void> in C++14
161struct logical_not : unary_function<T, bool>
162{
163    bool operator()(const T& x) const;
164};
165
166template <class T> // <class T=void> in C++14
167struct bit_and : unary_function<T, bool>
168{
169    bool operator()(const T& x, const T& y) const;
170};
171
172template <class T> // <class T=void> in C++14
173struct bit_or : unary_function<T, bool>
174{
175    bool operator()(const T& x, const T& y) const;
176};
177
178template <class T> // <class T=void> in C++14
179struct bit_xor : unary_function<T, bool>
180{
181    bool operator()(const T& x, const T& y) const;
182};
183
184template <class T=void> // C++14
185struct bit_xor : unary_function<T, bool>
186{
187    bool operator()(const T& x) const;
188};
189
190template <class Predicate>
191class unary_negate // deprecated in C++17
192    : public unary_function<typename Predicate::argument_type, bool>
193{
194public:
195    explicit unary_negate(const Predicate& pred);
196    bool operator()(const typename Predicate::argument_type& x) const;
197};
198
199template <class Predicate> // deprecated in C++17
200unary_negate<Predicate> not1(const Predicate& pred);
201
202template <class Predicate>
203class binary_negate // deprecated in C++17
204    : public binary_function<typename Predicate::first_argument_type,
205                             typename Predicate::second_argument_type,
206                             bool>
207{
208public:
209    explicit binary_negate(const Predicate& pred);
210    bool operator()(const typename Predicate::first_argument_type& x,
211                    const typename Predicate::second_argument_type& y) const;
212};
213
214template <class Predicate> // deprecated in C++17
215binary_negate<Predicate> not2(const Predicate& pred);
216
217template <class F> unspecified not_fn(F&& f); // C++17
218
219template<class T> struct is_bind_expression;
220template<class T> struct is_placeholder;
221
222    // See C++14 20.9.9, Function object binders
223template <class T> inline constexpr bool is_bind_expression_v
224  = is_bind_expression<T>::value; // C++17
225template <class T> inline constexpr int is_placeholder_v
226  = is_placeholder<T>::value; // C++17
227
228
229template<class Fn, class... BoundArgs>
230  unspecified bind(Fn&&, BoundArgs&&...);
231template<class R, class Fn, class... BoundArgs>
232  unspecified bind(Fn&&, BoundArgs&&...);
233
234namespace placeholders {
235  // M is the implementation-defined number of placeholders
236  extern unspecified _1;
237  extern unspecified _2;
238  .
239  .
240  .
241  extern unspecified _Mp;
242}
243
244template <class Operation>
245class binder1st     // deprecated in C++11, removed in C++17
246    : public unary_function<typename Operation::second_argument_type,
247                            typename Operation::result_type>
248{
249protected:
250    Operation                               op;
251    typename Operation::first_argument_type value;
252public:
253    binder1st(const Operation& x, const typename Operation::first_argument_type y);
254    typename Operation::result_type operator()(      typename Operation::second_argument_type& x) const;
255    typename Operation::result_type operator()(const typename Operation::second_argument_type& x) const;
256};
257
258template <class Operation, class T>
259binder1st<Operation> bind1st(const Operation& op, const T& x);  // deprecated in C++11, removed in C++17
260
261template <class Operation>
262class binder2nd     // deprecated in C++11, removed in C++17
263    : public unary_function<typename Operation::first_argument_type,
264                            typename Operation::result_type>
265{
266protected:
267    Operation                                op;
268    typename Operation::second_argument_type value;
269public:
270    binder2nd(const Operation& x, const typename Operation::second_argument_type y);
271    typename Operation::result_type operator()(      typename Operation::first_argument_type& x) const;
272    typename Operation::result_type operator()(const typename Operation::first_argument_type& x) const;
273};
274
275template <class Operation, class T>
276binder2nd<Operation> bind2nd(const Operation& op, const T& x);  // deprecated in C++11, removed in C++17
277
278template <class Arg, class Result>      // deprecated in C++11, removed in C++17
279class pointer_to_unary_function : public unary_function<Arg, Result>
280{
281public:
282    explicit pointer_to_unary_function(Result (*f)(Arg));
283    Result operator()(Arg x) const;
284};
285
286template <class Arg, class Result>
287pointer_to_unary_function<Arg,Result> ptr_fun(Result (*f)(Arg));      // deprecated in C++11, removed in C++17
288
289template <class Arg1, class Arg2, class Result>      // deprecated in C++11, removed in C++17
290class pointer_to_binary_function : public binary_function<Arg1, Arg2, Result>
291{
292public:
293    explicit pointer_to_binary_function(Result (*f)(Arg1, Arg2));
294    Result operator()(Arg1 x, Arg2 y) const;
295};
296
297template <class Arg1, class Arg2, class Result>
298pointer_to_binary_function<Arg1,Arg2,Result> ptr_fun(Result (*f)(Arg1,Arg2));      // deprecated in C++11, removed in C++17
299
300template<class S, class T>      // deprecated in C++11, removed in C++17
301class mem_fun_t : public unary_function<T*, S>
302{
303public:
304    explicit mem_fun_t(S (T::*p)());
305    S operator()(T* p) const;
306};
307
308template<class S, class T, class A>
309class mem_fun1_t : public binary_function<T*, A, S>      // deprecated in C++11, removed in C++17
310{
311public:
312    explicit mem_fun1_t(S (T::*p)(A));
313    S operator()(T* p, A x) const;
314};
315
316template<class S, class T>          mem_fun_t<S,T>    mem_fun(S (T::*f)());      // deprecated in C++11, removed in C++17
317template<class S, class T, class A> mem_fun1_t<S,T,A> mem_fun(S (T::*f)(A));     // deprecated in C++11, removed in C++17
318
319template<class S, class T>
320class mem_fun_ref_t : public unary_function<T, S>      // deprecated in C++11, removed in C++17
321{
322public:
323    explicit mem_fun_ref_t(S (T::*p)());
324    S operator()(T& p) const;
325};
326
327template<class S, class T, class A>
328class mem_fun1_ref_t : public binary_function<T, A, S>      // deprecated in C++11, removed in C++17
329{
330public:
331    explicit mem_fun1_ref_t(S (T::*p)(A));
332    S operator()(T& p, A x) const;
333};
334
335template<class S, class T>          mem_fun_ref_t<S,T>    mem_fun_ref(S (T::*f)());      // deprecated in C++11, removed in C++17
336template<class S, class T, class A> mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A));     // deprecated in C++11, removed in C++17
337
338template <class S, class T>
339class const_mem_fun_t : public unary_function<const T*, S>      // deprecated in C++11, removed in C++17
340{
341public:
342    explicit const_mem_fun_t(S (T::*p)() const);
343    S operator()(const T* p) const;
344};
345
346template <class S, class T, class A>
347class const_mem_fun1_t : public binary_function<const T*, A, S>      // deprecated in C++11, removed in C++17
348{
349public:
350    explicit const_mem_fun1_t(S (T::*p)(A) const);
351    S operator()(const T* p, A x) const;
352};
353
354template <class S, class T>          const_mem_fun_t<S,T>    mem_fun(S (T::*f)() const);      // deprecated in C++11, removed in C++17
355template <class S, class T, class A> const_mem_fun1_t<S,T,A> mem_fun(S (T::*f)(A) const);     // deprecated in C++11, removed in C++17
356
357template <class S, class T>
358class const_mem_fun_ref_t : public unary_function<T, S>      // deprecated in C++11, removed in C++17
359{
360public:
361    explicit const_mem_fun_ref_t(S (T::*p)() const);
362    S operator()(const T& p) const;
363};
364
365template <class S, class T, class A>
366class const_mem_fun1_ref_t : public binary_function<T, A, S>      // deprecated in C++11, removed in C++17
367{
368public:
369    explicit const_mem_fun1_ref_t(S (T::*p)(A) const);
370    S operator()(const T& p, A x) const;
371};
372
373template <class S, class T>          const_mem_fun_ref_t<S,T>    mem_fun_ref(S (T::*f)() const);   // deprecated in C++11, removed in C++17
374template <class S, class T, class A> const_mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A) const);  // deprecated in C++11, removed in C++17
375
376template<class R, class T> unspecified mem_fn(R T::*);
377
378class bad_function_call
379    : public exception
380{
381};
382
383template<class> class function; // undefined
384
385template<class R, class... ArgTypes>
386class function<R(ArgTypes...)>
387  : public unary_function<T1, R>      // iff sizeof...(ArgTypes) == 1 and
388                                      // ArgTypes contains T1
389  : public binary_function<T1, T2, R> // iff sizeof...(ArgTypes) == 2 and
390                                      // ArgTypes contains T1 and T2
391{
392public:
393    typedef R result_type;
394
395    // construct/copy/destroy:
396    function() noexcept;
397    function(nullptr_t) noexcept;
398    function(const function&);
399    function(function&&) noexcept;
400    template<class F>
401      function(F);
402    template<Allocator Alloc>
403      function(allocator_arg_t, const Alloc&) noexcept;            // removed in C++17
404    template<Allocator Alloc>
405      function(allocator_arg_t, const Alloc&, nullptr_t) noexcept; // removed in C++17
406    template<Allocator Alloc>
407      function(allocator_arg_t, const Alloc&, const function&);    // removed in C++17
408    template<Allocator Alloc>
409      function(allocator_arg_t, const Alloc&, function&&);         // removed in C++17
410    template<class F, Allocator Alloc>
411      function(allocator_arg_t, const Alloc&, F);                  // removed in C++17
412
413    function& operator=(const function&);
414    function& operator=(function&&) noexcept;
415    function& operator=(nullptr_t) noexcept;
416    template<class F>
417      function& operator=(F&&);
418    template<class F>
419      function& operator=(reference_wrapper<F>) noexcept;
420
421    ~function();
422
423    // function modifiers:
424    void swap(function&) noexcept;
425    template<class F, class Alloc>
426      void assign(F&&, const Alloc&);                 // Removed in C++17
427
428    // function capacity:
429    explicit operator bool() const noexcept;
430
431    // function invocation:
432    R operator()(ArgTypes...) const;
433
434    // function target access:
435    const std::type_info& target_type() const noexcept;
436    template <typename T>       T* target() noexcept;
437    template <typename T> const T* target() const noexcept;
438};
439
440// Null pointer comparisons:
441template <class R, class ... ArgTypes>
442  bool operator==(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
443
444template <class R, class ... ArgTypes>
445  bool operator==(nullptr_t, const function<R(ArgTypes...)>&) noexcept;
446
447template <class R, class ... ArgTypes>
448  bool operator!=(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
449
450template <class  R, class ... ArgTypes>
451  bool operator!=(nullptr_t, const function<R(ArgTypes...)>&) noexcept;
452
453// specialized algorithms:
454template <class  R, class ... ArgTypes>
455  void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&) noexcept;
456
457template <class T> struct hash;
458
459template <> struct hash<bool>;
460template <> struct hash<char>;
461template <> struct hash<signed char>;
462template <> struct hash<unsigned char>;
463template <> struct hash<char16_t>;
464template <> struct hash<char32_t>;
465template <> struct hash<wchar_t>;
466template <> struct hash<short>;
467template <> struct hash<unsigned short>;
468template <> struct hash<int>;
469template <> struct hash<unsigned int>;
470template <> struct hash<long>;
471template <> struct hash<long long>;
472template <> struct hash<unsigned long>;
473template <> struct hash<unsigned long long>;
474
475template <> struct hash<float>;
476template <> struct hash<double>;
477template <> struct hash<long double>;
478
479template<class T> struct hash<T*>;
480template <> struct hash<nullptr_t>;  // C++17
481
482}  // std
483
484POLICY:  For non-variadic implementations, the number of arguments is limited
485         to 3.  It is hoped that the need for non-variadic implementations
486         will be minimal.
487
488*/
489
490#include <__config>
491#include <type_traits>
492#include <typeinfo>
493#include <exception>
494#include <memory>
495#include <tuple>
496#include <utility>
497#include <version>
498
499#include <__functional_base>
500
501#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
502#pragma GCC system_header
503#endif
504
505_LIBCPP_BEGIN_NAMESPACE_STD
506
507#if _LIBCPP_STD_VER > 11
508template <class _Tp = void>
509#else
510template <class _Tp>
511#endif
512struct _LIBCPP_TEMPLATE_VIS plus : binary_function<_Tp, _Tp, _Tp>
513{
514    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
515    _Tp operator()(const _Tp& __x, const _Tp& __y) const
516        {return __x + __y;}
517};
518
519#if _LIBCPP_STD_VER > 11
520template <>
521struct _LIBCPP_TEMPLATE_VIS plus<void>
522{
523    template <class _T1, class _T2>
524    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
525    auto operator()(_T1&& __t, _T2&& __u) const
526    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u)))
527    -> decltype        (_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u))
528        { return        _VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u); }
529    typedef void is_transparent;
530};
531#endif
532
533
534#if _LIBCPP_STD_VER > 11
535template <class _Tp = void>
536#else
537template <class _Tp>
538#endif
539struct _LIBCPP_TEMPLATE_VIS minus : binary_function<_Tp, _Tp, _Tp>
540{
541    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
542    _Tp operator()(const _Tp& __x, const _Tp& __y) const
543        {return __x - __y;}
544};
545
546#if _LIBCPP_STD_VER > 11
547template <>
548struct _LIBCPP_TEMPLATE_VIS minus<void>
549{
550    template <class _T1, class _T2>
551    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
552    auto operator()(_T1&& __t, _T2&& __u) const
553    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u)))
554    -> decltype        (_VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u))
555        { return        _VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u); }
556    typedef void is_transparent;
557};
558#endif
559
560
561#if _LIBCPP_STD_VER > 11
562template <class _Tp = void>
563#else
564template <class _Tp>
565#endif
566struct _LIBCPP_TEMPLATE_VIS multiplies : binary_function<_Tp, _Tp, _Tp>
567{
568    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
569    _Tp operator()(const _Tp& __x, const _Tp& __y) const
570        {return __x * __y;}
571};
572
573#if _LIBCPP_STD_VER > 11
574template <>
575struct _LIBCPP_TEMPLATE_VIS multiplies<void>
576{
577    template <class _T1, class _T2>
578    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
579    auto operator()(_T1&& __t, _T2&& __u) const
580    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u)))
581    -> decltype        (_VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u))
582        { return        _VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u); }
583    typedef void is_transparent;
584};
585#endif
586
587
588#if _LIBCPP_STD_VER > 11
589template <class _Tp = void>
590#else
591template <class _Tp>
592#endif
593struct _LIBCPP_TEMPLATE_VIS divides : binary_function<_Tp, _Tp, _Tp>
594{
595    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
596    _Tp operator()(const _Tp& __x, const _Tp& __y) const
597        {return __x / __y;}
598};
599
600#if _LIBCPP_STD_VER > 11
601template <>
602struct _LIBCPP_TEMPLATE_VIS divides<void>
603{
604    template <class _T1, class _T2>
605    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
606    auto operator()(_T1&& __t, _T2&& __u) const
607    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u)))
608    -> decltype        (_VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u))
609        { return        _VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u); }
610    typedef void is_transparent;
611};
612#endif
613
614
615#if _LIBCPP_STD_VER > 11
616template <class _Tp = void>
617#else
618template <class _Tp>
619#endif
620struct _LIBCPP_TEMPLATE_VIS modulus : binary_function<_Tp, _Tp, _Tp>
621{
622    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
623    _Tp operator()(const _Tp& __x, const _Tp& __y) const
624        {return __x % __y;}
625};
626
627#if _LIBCPP_STD_VER > 11
628template <>
629struct _LIBCPP_TEMPLATE_VIS modulus<void>
630{
631    template <class _T1, class _T2>
632    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
633    auto operator()(_T1&& __t, _T2&& __u) const
634    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u)))
635    -> decltype        (_VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u))
636        { return        _VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u); }
637    typedef void is_transparent;
638};
639#endif
640
641
642#if _LIBCPP_STD_VER > 11
643template <class _Tp = void>
644#else
645template <class _Tp>
646#endif
647struct _LIBCPP_TEMPLATE_VIS negate : unary_function<_Tp, _Tp>
648{
649    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
650    _Tp operator()(const _Tp& __x) const
651        {return -__x;}
652};
653
654#if _LIBCPP_STD_VER > 11
655template <>
656struct _LIBCPP_TEMPLATE_VIS negate<void>
657{
658    template <class _Tp>
659    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
660    auto operator()(_Tp&& __x) const
661    _NOEXCEPT_(noexcept(- _VSTD::forward<_Tp>(__x)))
662    -> decltype        (- _VSTD::forward<_Tp>(__x))
663        { return        - _VSTD::forward<_Tp>(__x); }
664    typedef void is_transparent;
665};
666#endif
667
668
669#if _LIBCPP_STD_VER > 11
670template <class _Tp = void>
671#else
672template <class _Tp>
673#endif
674struct _LIBCPP_TEMPLATE_VIS equal_to : binary_function<_Tp, _Tp, bool>
675{
676    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
677    bool operator()(const _Tp& __x, const _Tp& __y) const
678        {return __x == __y;}
679};
680
681#if _LIBCPP_STD_VER > 11
682template <>
683struct _LIBCPP_TEMPLATE_VIS equal_to<void>
684{
685    template <class _T1, class _T2>
686    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
687    auto operator()(_T1&& __t, _T2&& __u) const
688    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u)))
689    -> decltype        (_VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u))
690        { return        _VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u); }
691    typedef void is_transparent;
692};
693#endif
694
695
696#if _LIBCPP_STD_VER > 11
697template <class _Tp = void>
698#else
699template <class _Tp>
700#endif
701struct _LIBCPP_TEMPLATE_VIS not_equal_to : binary_function<_Tp, _Tp, bool>
702{
703    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
704    bool operator()(const _Tp& __x, const _Tp& __y) const
705        {return __x != __y;}
706};
707
708#if _LIBCPP_STD_VER > 11
709template <>
710struct _LIBCPP_TEMPLATE_VIS not_equal_to<void>
711{
712    template <class _T1, class _T2>
713    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
714    auto operator()(_T1&& __t, _T2&& __u) const
715    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u)))
716    -> decltype        (_VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u))
717        { return        _VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u); }
718    typedef void is_transparent;
719};
720#endif
721
722
723#if _LIBCPP_STD_VER > 11
724template <class _Tp = void>
725#else
726template <class _Tp>
727#endif
728struct _LIBCPP_TEMPLATE_VIS greater : binary_function<_Tp, _Tp, bool>
729{
730    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
731    bool operator()(const _Tp& __x, const _Tp& __y) const
732        {return __x > __y;}
733};
734
735#if _LIBCPP_STD_VER > 11
736template <>
737struct _LIBCPP_TEMPLATE_VIS greater<void>
738{
739    template <class _T1, class _T2>
740    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
741    auto operator()(_T1&& __t, _T2&& __u) const
742    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u)))
743    -> decltype        (_VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u))
744        { return        _VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u); }
745    typedef void is_transparent;
746};
747#endif
748
749
750// less in <__functional_base>
751
752#if _LIBCPP_STD_VER > 11
753template <class _Tp = void>
754#else
755template <class _Tp>
756#endif
757struct _LIBCPP_TEMPLATE_VIS greater_equal : binary_function<_Tp, _Tp, bool>
758{
759    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
760    bool operator()(const _Tp& __x, const _Tp& __y) const
761        {return __x >= __y;}
762};
763
764#if _LIBCPP_STD_VER > 11
765template <>
766struct _LIBCPP_TEMPLATE_VIS greater_equal<void>
767{
768    template <class _T1, class _T2>
769    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
770    auto operator()(_T1&& __t, _T2&& __u) const
771    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u)))
772    -> decltype        (_VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u))
773        { return        _VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u); }
774    typedef void is_transparent;
775};
776#endif
777
778
779#if _LIBCPP_STD_VER > 11
780template <class _Tp = void>
781#else
782template <class _Tp>
783#endif
784struct _LIBCPP_TEMPLATE_VIS less_equal : binary_function<_Tp, _Tp, bool>
785{
786    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
787    bool operator()(const _Tp& __x, const _Tp& __y) const
788        {return __x <= __y;}
789};
790
791#if _LIBCPP_STD_VER > 11
792template <>
793struct _LIBCPP_TEMPLATE_VIS less_equal<void>
794{
795    template <class _T1, class _T2>
796    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
797    auto operator()(_T1&& __t, _T2&& __u) const
798    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u)))
799    -> decltype        (_VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u))
800        { return        _VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u); }
801    typedef void is_transparent;
802};
803#endif
804
805
806#if _LIBCPP_STD_VER > 11
807template <class _Tp = void>
808#else
809template <class _Tp>
810#endif
811struct _LIBCPP_TEMPLATE_VIS logical_and : binary_function<_Tp, _Tp, bool>
812{
813    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
814    bool operator()(const _Tp& __x, const _Tp& __y) const
815        {return __x && __y;}
816};
817
818#if _LIBCPP_STD_VER > 11
819template <>
820struct _LIBCPP_TEMPLATE_VIS logical_and<void>
821{
822    template <class _T1, class _T2>
823    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
824    auto operator()(_T1&& __t, _T2&& __u) const
825    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u)))
826    -> decltype        (_VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u))
827        { return        _VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u); }
828    typedef void is_transparent;
829};
830#endif
831
832
833#if _LIBCPP_STD_VER > 11
834template <class _Tp = void>
835#else
836template <class _Tp>
837#endif
838struct _LIBCPP_TEMPLATE_VIS logical_or : binary_function<_Tp, _Tp, bool>
839{
840    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
841    bool operator()(const _Tp& __x, const _Tp& __y) const
842        {return __x || __y;}
843};
844
845#if _LIBCPP_STD_VER > 11
846template <>
847struct _LIBCPP_TEMPLATE_VIS logical_or<void>
848{
849    template <class _T1, class _T2>
850    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
851    auto operator()(_T1&& __t, _T2&& __u) const
852    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u)))
853    -> decltype        (_VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u))
854        { return        _VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u); }
855    typedef void is_transparent;
856};
857#endif
858
859
860#if _LIBCPP_STD_VER > 11
861template <class _Tp = void>
862#else
863template <class _Tp>
864#endif
865struct _LIBCPP_TEMPLATE_VIS logical_not : unary_function<_Tp, bool>
866{
867    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
868    bool operator()(const _Tp& __x) const
869        {return !__x;}
870};
871
872#if _LIBCPP_STD_VER > 11
873template <>
874struct _LIBCPP_TEMPLATE_VIS logical_not<void>
875{
876    template <class _Tp>
877    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
878    auto operator()(_Tp&& __x) const
879    _NOEXCEPT_(noexcept(!_VSTD::forward<_Tp>(__x)))
880    -> decltype        (!_VSTD::forward<_Tp>(__x))
881        { return        !_VSTD::forward<_Tp>(__x); }
882    typedef void is_transparent;
883};
884#endif
885
886
887#if _LIBCPP_STD_VER > 11
888template <class _Tp = void>
889#else
890template <class _Tp>
891#endif
892struct _LIBCPP_TEMPLATE_VIS bit_and : binary_function<_Tp, _Tp, _Tp>
893{
894    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
895    _Tp operator()(const _Tp& __x, const _Tp& __y) const
896        {return __x & __y;}
897};
898
899#if _LIBCPP_STD_VER > 11
900template <>
901struct _LIBCPP_TEMPLATE_VIS bit_and<void>
902{
903    template <class _T1, class _T2>
904    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
905    auto operator()(_T1&& __t, _T2&& __u) const
906    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u)))
907    -> decltype        (_VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u))
908        { return        _VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u); }
909    typedef void is_transparent;
910};
911#endif
912
913
914#if _LIBCPP_STD_VER > 11
915template <class _Tp = void>
916#else
917template <class _Tp>
918#endif
919struct _LIBCPP_TEMPLATE_VIS bit_or : binary_function<_Tp, _Tp, _Tp>
920{
921    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
922    _Tp operator()(const _Tp& __x, const _Tp& __y) const
923        {return __x | __y;}
924};
925
926#if _LIBCPP_STD_VER > 11
927template <>
928struct _LIBCPP_TEMPLATE_VIS bit_or<void>
929{
930    template <class _T1, class _T2>
931    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
932    auto operator()(_T1&& __t, _T2&& __u) const
933    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u)))
934    -> decltype        (_VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u))
935        { return        _VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u); }
936    typedef void is_transparent;
937};
938#endif
939
940
941#if _LIBCPP_STD_VER > 11
942template <class _Tp = void>
943#else
944template <class _Tp>
945#endif
946struct _LIBCPP_TEMPLATE_VIS bit_xor : binary_function<_Tp, _Tp, _Tp>
947{
948    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
949    _Tp operator()(const _Tp& __x, const _Tp& __y) const
950        {return __x ^ __y;}
951};
952
953#if _LIBCPP_STD_VER > 11
954template <>
955struct _LIBCPP_TEMPLATE_VIS bit_xor<void>
956{
957    template <class _T1, class _T2>
958    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
959    auto operator()(_T1&& __t, _T2&& __u) const
960    _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u)))
961    -> decltype        (_VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u))
962        { return        _VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u); }
963    typedef void is_transparent;
964};
965#endif
966
967
968#if _LIBCPP_STD_VER > 11
969template <class _Tp = void>
970struct _LIBCPP_TEMPLATE_VIS bit_not : unary_function<_Tp, _Tp>
971{
972    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
973    _Tp operator()(const _Tp& __x) const
974        {return ~__x;}
975};
976
977template <>
978struct _LIBCPP_TEMPLATE_VIS bit_not<void>
979{
980    template <class _Tp>
981    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
982    auto operator()(_Tp&& __x) const
983    _NOEXCEPT_(noexcept(~_VSTD::forward<_Tp>(__x)))
984    -> decltype        (~_VSTD::forward<_Tp>(__x))
985        { return        ~_VSTD::forward<_Tp>(__x); }
986    typedef void is_transparent;
987};
988#endif
989
990template <class _Predicate>
991class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 unary_negate
992    : public unary_function<typename _Predicate::argument_type, bool>
993{
994    _Predicate __pred_;
995public:
996    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
997    explicit unary_negate(const _Predicate& __pred)
998        : __pred_(__pred) {}
999    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1000    bool operator()(const typename _Predicate::argument_type& __x) const
1001        {return !__pred_(__x);}
1002};
1003
1004template <class _Predicate>
1005_LIBCPP_DEPRECATED_IN_CXX17 inline _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1006unary_negate<_Predicate>
1007not1(const _Predicate& __pred) {return unary_negate<_Predicate>(__pred);}
1008
1009template <class _Predicate>
1010class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 binary_negate
1011    : public binary_function<typename _Predicate::first_argument_type,
1012                             typename _Predicate::second_argument_type,
1013                             bool>
1014{
1015    _Predicate __pred_;
1016public:
1017    _LIBCPP_INLINE_VISIBILITY explicit _LIBCPP_CONSTEXPR_AFTER_CXX11
1018    binary_negate(const _Predicate& __pred) : __pred_(__pred) {}
1019
1020    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1021    bool operator()(const typename _Predicate::first_argument_type& __x,
1022                    const typename _Predicate::second_argument_type& __y) const
1023        {return !__pred_(__x, __y);}
1024};
1025
1026template <class _Predicate>
1027_LIBCPP_DEPRECATED_IN_CXX17 inline _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1028binary_negate<_Predicate>
1029not2(const _Predicate& __pred) {return binary_negate<_Predicate>(__pred);}
1030
1031#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
1032template <class __Operation>
1033class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binder1st
1034    : public unary_function<typename __Operation::second_argument_type,
1035                            typename __Operation::result_type>
1036{
1037protected:
1038    __Operation                               op;
1039    typename __Operation::first_argument_type value;
1040public:
1041    _LIBCPP_INLINE_VISIBILITY binder1st(const __Operation& __x,
1042                               const typename __Operation::first_argument_type __y)
1043        : op(__x), value(__y) {}
1044    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
1045        (typename __Operation::second_argument_type& __x) const
1046            {return op(value, __x);}
1047    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
1048        (const typename __Operation::second_argument_type& __x) const
1049            {return op(value, __x);}
1050};
1051
1052template <class __Operation, class _Tp>
1053_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1054binder1st<__Operation>
1055bind1st(const __Operation& __op, const _Tp& __x)
1056    {return binder1st<__Operation>(__op, __x);}
1057
1058template <class __Operation>
1059class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binder2nd
1060    : public unary_function<typename __Operation::first_argument_type,
1061                            typename __Operation::result_type>
1062{
1063protected:
1064    __Operation                                op;
1065    typename __Operation::second_argument_type value;
1066public:
1067    _LIBCPP_INLINE_VISIBILITY
1068    binder2nd(const __Operation& __x, const typename __Operation::second_argument_type __y)
1069        : op(__x), value(__y) {}
1070    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
1071        (      typename __Operation::first_argument_type& __x) const
1072            {return op(__x, value);}
1073    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
1074        (const typename __Operation::first_argument_type& __x) const
1075            {return op(__x, value);}
1076};
1077
1078template <class __Operation, class _Tp>
1079_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1080binder2nd<__Operation>
1081bind2nd(const __Operation& __op, const _Tp& __x)
1082    {return binder2nd<__Operation>(__op, __x);}
1083
1084template <class _Arg, class _Result>
1085class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 pointer_to_unary_function
1086    : public unary_function<_Arg, _Result>
1087{
1088    _Result (*__f_)(_Arg);
1089public:
1090    _LIBCPP_INLINE_VISIBILITY explicit pointer_to_unary_function(_Result (*__f)(_Arg))
1091        : __f_(__f) {}
1092    _LIBCPP_INLINE_VISIBILITY _Result operator()(_Arg __x) const
1093        {return __f_(__x);}
1094};
1095
1096template <class _Arg, class _Result>
1097_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1098pointer_to_unary_function<_Arg,_Result>
1099ptr_fun(_Result (*__f)(_Arg))
1100    {return pointer_to_unary_function<_Arg,_Result>(__f);}
1101
1102template <class _Arg1, class _Arg2, class _Result>
1103class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 pointer_to_binary_function
1104    : public binary_function<_Arg1, _Arg2, _Result>
1105{
1106    _Result (*__f_)(_Arg1, _Arg2);
1107public:
1108    _LIBCPP_INLINE_VISIBILITY explicit pointer_to_binary_function(_Result (*__f)(_Arg1, _Arg2))
1109        : __f_(__f) {}
1110    _LIBCPP_INLINE_VISIBILITY _Result operator()(_Arg1 __x, _Arg2 __y) const
1111        {return __f_(__x, __y);}
1112};
1113
1114template <class _Arg1, class _Arg2, class _Result>
1115_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1116pointer_to_binary_function<_Arg1,_Arg2,_Result>
1117ptr_fun(_Result (*__f)(_Arg1,_Arg2))
1118    {return pointer_to_binary_function<_Arg1,_Arg2,_Result>(__f);}
1119
1120template<class _Sp, class _Tp>
1121class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun_t
1122    : public unary_function<_Tp*, _Sp>
1123{
1124    _Sp (_Tp::*__p_)();
1125public:
1126    _LIBCPP_INLINE_VISIBILITY explicit mem_fun_t(_Sp (_Tp::*__p)())
1127        : __p_(__p) {}
1128    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp* __p) const
1129        {return (__p->*__p_)();}
1130};
1131
1132template<class _Sp, class _Tp, class _Ap>
1133class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun1_t
1134    : public binary_function<_Tp*, _Ap, _Sp>
1135{
1136    _Sp (_Tp::*__p_)(_Ap);
1137public:
1138    _LIBCPP_INLINE_VISIBILITY explicit mem_fun1_t(_Sp (_Tp::*__p)(_Ap))
1139        : __p_(__p) {}
1140    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp* __p, _Ap __x) const
1141        {return (__p->*__p_)(__x);}
1142};
1143
1144template<class _Sp, class _Tp>
1145_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1146mem_fun_t<_Sp,_Tp>
1147mem_fun(_Sp (_Tp::*__f)())
1148    {return mem_fun_t<_Sp,_Tp>(__f);}
1149
1150template<class _Sp, class _Tp, class _Ap>
1151_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1152mem_fun1_t<_Sp,_Tp,_Ap>
1153mem_fun(_Sp (_Tp::*__f)(_Ap))
1154    {return mem_fun1_t<_Sp,_Tp,_Ap>(__f);}
1155
1156template<class _Sp, class _Tp>
1157class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun_ref_t
1158    : public unary_function<_Tp, _Sp>
1159{
1160    _Sp (_Tp::*__p_)();
1161public:
1162    _LIBCPP_INLINE_VISIBILITY explicit mem_fun_ref_t(_Sp (_Tp::*__p)())
1163        : __p_(__p) {}
1164    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp& __p) const
1165        {return (__p.*__p_)();}
1166};
1167
1168template<class _Sp, class _Tp, class _Ap>
1169class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun1_ref_t
1170    : public binary_function<_Tp, _Ap, _Sp>
1171{
1172    _Sp (_Tp::*__p_)(_Ap);
1173public:
1174    _LIBCPP_INLINE_VISIBILITY explicit mem_fun1_ref_t(_Sp (_Tp::*__p)(_Ap))
1175        : __p_(__p) {}
1176    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp& __p, _Ap __x) const
1177        {return (__p.*__p_)(__x);}
1178};
1179
1180template<class _Sp, class _Tp>
1181_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1182mem_fun_ref_t<_Sp,_Tp>
1183mem_fun_ref(_Sp (_Tp::*__f)())
1184    {return mem_fun_ref_t<_Sp,_Tp>(__f);}
1185
1186template<class _Sp, class _Tp, class _Ap>
1187_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1188mem_fun1_ref_t<_Sp,_Tp,_Ap>
1189mem_fun_ref(_Sp (_Tp::*__f)(_Ap))
1190    {return mem_fun1_ref_t<_Sp,_Tp,_Ap>(__f);}
1191
1192template <class _Sp, class _Tp>
1193class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun_t
1194    : public unary_function<const _Tp*, _Sp>
1195{
1196    _Sp (_Tp::*__p_)() const;
1197public:
1198    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun_t(_Sp (_Tp::*__p)() const)
1199        : __p_(__p) {}
1200    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp* __p) const
1201        {return (__p->*__p_)();}
1202};
1203
1204template <class _Sp, class _Tp, class _Ap>
1205class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun1_t
1206    : public binary_function<const _Tp*, _Ap, _Sp>
1207{
1208    _Sp (_Tp::*__p_)(_Ap) const;
1209public:
1210    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun1_t(_Sp (_Tp::*__p)(_Ap) const)
1211        : __p_(__p) {}
1212    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp* __p, _Ap __x) const
1213        {return (__p->*__p_)(__x);}
1214};
1215
1216template <class _Sp, class _Tp>
1217_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1218const_mem_fun_t<_Sp,_Tp>
1219mem_fun(_Sp (_Tp::*__f)() const)
1220    {return const_mem_fun_t<_Sp,_Tp>(__f);}
1221
1222template <class _Sp, class _Tp, class _Ap>
1223_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1224const_mem_fun1_t<_Sp,_Tp,_Ap>
1225mem_fun(_Sp (_Tp::*__f)(_Ap) const)
1226    {return const_mem_fun1_t<_Sp,_Tp,_Ap>(__f);}
1227
1228template <class _Sp, class _Tp>
1229class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun_ref_t
1230    : public unary_function<_Tp, _Sp>
1231{
1232    _Sp (_Tp::*__p_)() const;
1233public:
1234    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun_ref_t(_Sp (_Tp::*__p)() const)
1235        : __p_(__p) {}
1236    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp& __p) const
1237        {return (__p.*__p_)();}
1238};
1239
1240template <class _Sp, class _Tp, class _Ap>
1241class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun1_ref_t
1242    : public binary_function<_Tp, _Ap, _Sp>
1243{
1244    _Sp (_Tp::*__p_)(_Ap) const;
1245public:
1246    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun1_ref_t(_Sp (_Tp::*__p)(_Ap) const)
1247        : __p_(__p) {}
1248    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp& __p, _Ap __x) const
1249        {return (__p.*__p_)(__x);}
1250};
1251
1252template <class _Sp, class _Tp>
1253_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1254const_mem_fun_ref_t<_Sp,_Tp>
1255mem_fun_ref(_Sp (_Tp::*__f)() const)
1256    {return const_mem_fun_ref_t<_Sp,_Tp>(__f);}
1257
1258template <class _Sp, class _Tp, class _Ap>
1259_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
1260const_mem_fun1_ref_t<_Sp,_Tp,_Ap>
1261mem_fun_ref(_Sp (_Tp::*__f)(_Ap) const)
1262    {return const_mem_fun1_ref_t<_Sp,_Tp,_Ap>(__f);}
1263#endif
1264
1265////////////////////////////////////////////////////////////////////////////////
1266//                                MEMFUN
1267//==============================================================================
1268
1269template <class _Tp>
1270class __mem_fn
1271    : public __weak_result_type<_Tp>
1272{
1273public:
1274    // types
1275    typedef _Tp type;
1276private:
1277    type __f_;
1278
1279public:
1280    _LIBCPP_INLINE_VISIBILITY __mem_fn(type __f) _NOEXCEPT : __f_(__f) {}
1281
1282#ifndef _LIBCPP_CXX03_LANG
1283    // invoke
1284    template <class... _ArgTypes>
1285    _LIBCPP_INLINE_VISIBILITY
1286    typename __invoke_return<type, _ArgTypes...>::type
1287    operator() (_ArgTypes&&... __args) const {
1288        return __invoke(__f_, _VSTD::forward<_ArgTypes>(__args)...);
1289    }
1290#else
1291
1292    template <class _A0>
1293    _LIBCPP_INLINE_VISIBILITY
1294    typename __invoke_return0<type, _A0>::type
1295    operator() (_A0& __a0) const {
1296        return __invoke(__f_, __a0);
1297    }
1298
1299    template <class _A0>
1300    _LIBCPP_INLINE_VISIBILITY
1301    typename __invoke_return0<type, _A0 const>::type
1302    operator() (_A0 const& __a0) const {
1303        return __invoke(__f_, __a0);
1304    }
1305
1306    template <class _A0, class _A1>
1307    _LIBCPP_INLINE_VISIBILITY
1308    typename __invoke_return1<type, _A0, _A1>::type
1309    operator() (_A0& __a0, _A1& __a1) const {
1310        return __invoke(__f_, __a0, __a1);
1311    }
1312
1313    template <class _A0, class _A1>
1314    _LIBCPP_INLINE_VISIBILITY
1315    typename __invoke_return1<type, _A0 const, _A1>::type
1316    operator() (_A0 const& __a0, _A1& __a1) const {
1317        return __invoke(__f_, __a0, __a1);
1318    }
1319
1320    template <class _A0, class _A1>
1321    _LIBCPP_INLINE_VISIBILITY
1322    typename __invoke_return1<type, _A0, _A1 const>::type
1323    operator() (_A0& __a0, _A1 const& __a1) const {
1324        return __invoke(__f_, __a0, __a1);
1325    }
1326
1327    template <class _A0, class _A1>
1328    _LIBCPP_INLINE_VISIBILITY
1329    typename __invoke_return1<type, _A0 const, _A1 const>::type
1330    operator() (_A0 const& __a0, _A1 const& __a1) const {
1331        return __invoke(__f_, __a0, __a1);
1332    }
1333
1334    template <class _A0, class _A1, class _A2>
1335    _LIBCPP_INLINE_VISIBILITY
1336    typename __invoke_return2<type, _A0, _A1, _A2>::type
1337    operator() (_A0& __a0, _A1& __a1, _A2& __a2) const {
1338        return __invoke(__f_, __a0, __a1, __a2);
1339    }
1340
1341    template <class _A0, class _A1, class _A2>
1342    _LIBCPP_INLINE_VISIBILITY
1343    typename __invoke_return2<type, _A0 const, _A1, _A2>::type
1344    operator() (_A0 const& __a0, _A1& __a1, _A2& __a2) const {
1345        return __invoke(__f_, __a0, __a1, __a2);
1346    }
1347
1348    template <class _A0, class _A1, class _A2>
1349    _LIBCPP_INLINE_VISIBILITY
1350    typename __invoke_return2<type, _A0, _A1 const, _A2>::type
1351    operator() (_A0& __a0, _A1 const& __a1, _A2& __a2) const {
1352        return __invoke(__f_, __a0, __a1, __a2);
1353    }
1354
1355    template <class _A0, class _A1, class _A2>
1356    _LIBCPP_INLINE_VISIBILITY
1357    typename __invoke_return2<type, _A0, _A1, _A2 const>::type
1358    operator() (_A0& __a0, _A1& __a1, _A2 const& __a2) const {
1359        return __invoke(__f_, __a0, __a1, __a2);
1360    }
1361
1362    template <class _A0, class _A1, class _A2>
1363    _LIBCPP_INLINE_VISIBILITY
1364    typename __invoke_return2<type, _A0 const, _A1 const, _A2>::type
1365    operator() (_A0 const& __a0, _A1 const& __a1, _A2& __a2) const {
1366        return __invoke(__f_, __a0, __a1, __a2);
1367    }
1368
1369    template <class _A0, class _A1, class _A2>
1370    _LIBCPP_INLINE_VISIBILITY
1371    typename __invoke_return2<type, _A0 const, _A1, _A2 const>::type
1372    operator() (_A0 const& __a0, _A1& __a1, _A2 const& __a2) const {
1373        return __invoke(__f_, __a0, __a1, __a2);
1374    }
1375
1376    template <class _A0, class _A1, class _A2>
1377    _LIBCPP_INLINE_VISIBILITY
1378    typename __invoke_return2<type, _A0, _A1 const, _A2 const>::type
1379    operator() (_A0& __a0, _A1 const& __a1, _A2 const& __a2) const {
1380        return __invoke(__f_, __a0, __a1, __a2);
1381    }
1382
1383    template <class _A0, class _A1, class _A2>
1384    _LIBCPP_INLINE_VISIBILITY
1385    typename __invoke_return2<type, _A0 const, _A1 const, _A2 const>::type
1386    operator() (_A0 const& __a0, _A1 const& __a1, _A2 const& __a2) const {
1387        return __invoke(__f_, __a0, __a1, __a2);
1388    }
1389#endif
1390};
1391
1392template<class _Rp, class _Tp>
1393inline _LIBCPP_INLINE_VISIBILITY
1394__mem_fn<_Rp _Tp::*>
1395mem_fn(_Rp _Tp::* __pm) _NOEXCEPT
1396{
1397    return __mem_fn<_Rp _Tp::*>(__pm);
1398}
1399
1400////////////////////////////////////////////////////////////////////////////////
1401//                                FUNCTION
1402//==============================================================================
1403
1404// bad_function_call
1405
1406class _LIBCPP_EXCEPTION_ABI bad_function_call
1407    : public exception
1408{
1409#ifdef _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
1410public:
1411    virtual ~bad_function_call() _NOEXCEPT;
1412
1413    virtual const char* what() const _NOEXCEPT;
1414#endif
1415};
1416
1417_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
1418void __throw_bad_function_call()
1419{
1420#ifndef _LIBCPP_NO_EXCEPTIONS
1421    throw bad_function_call();
1422#else
1423    _VSTD::abort();
1424#endif
1425}
1426
1427template<class _Fp> class _LIBCPP_TEMPLATE_VIS function; // undefined
1428
1429namespace __function
1430{
1431
1432template<class _Rp>
1433struct __maybe_derive_from_unary_function
1434{
1435};
1436
1437template<class _Rp, class _A1>
1438struct __maybe_derive_from_unary_function<_Rp(_A1)>
1439    : public unary_function<_A1, _Rp>
1440{
1441};
1442
1443template<class _Rp>
1444struct __maybe_derive_from_binary_function
1445{
1446};
1447
1448template<class _Rp, class _A1, class _A2>
1449struct __maybe_derive_from_binary_function<_Rp(_A1, _A2)>
1450    : public binary_function<_A1, _A2, _Rp>
1451{
1452};
1453
1454template <class _Fp>
1455_LIBCPP_INLINE_VISIBILITY
1456bool __not_null(_Fp const&) { return true; }
1457
1458template <class _Fp>
1459_LIBCPP_INLINE_VISIBILITY
1460bool __not_null(_Fp* __ptr) { return __ptr; }
1461
1462template <class _Ret, class _Class>
1463_LIBCPP_INLINE_VISIBILITY
1464bool __not_null(_Ret _Class::*__ptr) { return __ptr; }
1465
1466template <class _Fp>
1467_LIBCPP_INLINE_VISIBILITY
1468bool __not_null(function<_Fp> const& __f) { return !!__f; }
1469
1470} // namespace __function
1471
1472#ifndef _LIBCPP_CXX03_LANG
1473
1474namespace __function {
1475
1476// __alloc_func holds a functor and an allocator.
1477
1478template <class _Fp, class _Ap, class _FB> class __alloc_func;
1479
1480template <class _Fp, class _Ap, class _Rp, class... _ArgTypes>
1481class __alloc_func<_Fp, _Ap, _Rp(_ArgTypes...)>
1482{
1483    __compressed_pair<_Fp, _Ap> __f_;
1484
1485  public:
1486    typedef _Fp _Target;
1487    typedef _Ap _Alloc;
1488
1489    _LIBCPP_INLINE_VISIBILITY
1490    const _Target& __target() const { return __f_.first(); }
1491
1492    _LIBCPP_INLINE_VISIBILITY
1493    const _Alloc& __allocator() const { return __f_.second(); }
1494
1495    _LIBCPP_INLINE_VISIBILITY
1496    explicit __alloc_func(_Target&& __f)
1497        : __f_(piecewise_construct, _VSTD::forward_as_tuple(_VSTD::move(__f)),
1498               _VSTD::forward_as_tuple())
1499    {
1500    }
1501
1502    _LIBCPP_INLINE_VISIBILITY
1503    explicit __alloc_func(const _Target& __f, const _Alloc& __a)
1504        : __f_(piecewise_construct, _VSTD::forward_as_tuple(__f),
1505               _VSTD::forward_as_tuple(__a))
1506    {
1507    }
1508
1509    _LIBCPP_INLINE_VISIBILITY
1510    explicit __alloc_func(const _Target& __f, _Alloc&& __a)
1511        : __f_(piecewise_construct, _VSTD::forward_as_tuple(__f),
1512               _VSTD::forward_as_tuple(_VSTD::move(__a)))
1513    {
1514    }
1515
1516    _LIBCPP_INLINE_VISIBILITY
1517    explicit __alloc_func(_Target&& __f, _Alloc&& __a)
1518        : __f_(piecewise_construct, _VSTD::forward_as_tuple(_VSTD::move(__f)),
1519               _VSTD::forward_as_tuple(_VSTD::move(__a)))
1520    {
1521    }
1522
1523    _LIBCPP_INLINE_VISIBILITY
1524    _Rp operator()(_ArgTypes&&... __arg)
1525    {
1526        typedef __invoke_void_return_wrapper<_Rp> _Invoker;
1527        return _Invoker::__call(__f_.first(),
1528                                _VSTD::forward<_ArgTypes>(__arg)...);
1529    }
1530
1531    _LIBCPP_INLINE_VISIBILITY
1532    __alloc_func* __clone() const
1533    {
1534        typedef allocator_traits<_Alloc> __alloc_traits;
1535        typedef
1536            typename __rebind_alloc_helper<__alloc_traits, __alloc_func>::type
1537                _AA;
1538        _AA __a(__f_.second());
1539        typedef __allocator_destructor<_AA> _Dp;
1540        unique_ptr<__alloc_func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
1541        ::new ((void*)__hold.get()) __alloc_func(__f_.first(), _Alloc(__a));
1542        return __hold.release();
1543    }
1544
1545    _LIBCPP_INLINE_VISIBILITY
1546    void destroy() _NOEXCEPT { __f_.~__compressed_pair<_Target, _Alloc>(); }
1547};
1548
1549// __base provides an abstract interface for copyable functors.
1550
1551template<class _Fp> class __base;
1552
1553template<class _Rp, class ..._ArgTypes>
1554class __base<_Rp(_ArgTypes...)>
1555{
1556    __base(const __base&);
1557    __base& operator=(const __base&);
1558public:
1559    _LIBCPP_INLINE_VISIBILITY __base() {}
1560    _LIBCPP_INLINE_VISIBILITY virtual ~__base() {}
1561    virtual __base* __clone() const = 0;
1562    virtual void __clone(__base*) const = 0;
1563    virtual void destroy() _NOEXCEPT = 0;
1564    virtual void destroy_deallocate() _NOEXCEPT = 0;
1565    virtual _Rp operator()(_ArgTypes&& ...) = 0;
1566#ifndef _LIBCPP_NO_RTTI
1567    virtual const void* target(const type_info&) const _NOEXCEPT = 0;
1568    virtual const std::type_info& target_type() const _NOEXCEPT = 0;
1569#endif  // _LIBCPP_NO_RTTI
1570};
1571
1572// __func implements __base for a given functor type.
1573
1574template<class _FD, class _Alloc, class _FB> class __func;
1575
1576template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1577class __func<_Fp, _Alloc, _Rp(_ArgTypes...)>
1578    : public  __base<_Rp(_ArgTypes...)>
1579{
1580    __alloc_func<_Fp, _Alloc, _Rp(_ArgTypes...)> __f_;
1581public:
1582    _LIBCPP_INLINE_VISIBILITY
1583    explicit __func(_Fp&& __f)
1584        : __f_(_VSTD::move(__f)) {}
1585
1586    _LIBCPP_INLINE_VISIBILITY
1587    explicit __func(const _Fp& __f, const _Alloc& __a)
1588        : __f_(__f, __a) {}
1589
1590    _LIBCPP_INLINE_VISIBILITY
1591    explicit __func(const _Fp& __f, _Alloc&& __a)
1592        : __f_(__f, _VSTD::move(__a)) {}
1593
1594    _LIBCPP_INLINE_VISIBILITY
1595    explicit __func(_Fp&& __f, _Alloc&& __a)
1596        : __f_(_VSTD::move(__f), _VSTD::move(__a)) {}
1597
1598    virtual __base<_Rp(_ArgTypes...)>* __clone() const;
1599    virtual void __clone(__base<_Rp(_ArgTypes...)>*) const;
1600    virtual void destroy() _NOEXCEPT;
1601    virtual void destroy_deallocate() _NOEXCEPT;
1602    virtual _Rp operator()(_ArgTypes&&... __arg);
1603#ifndef _LIBCPP_NO_RTTI
1604    virtual const void* target(const type_info&) const _NOEXCEPT;
1605    virtual const std::type_info& target_type() const _NOEXCEPT;
1606#endif  // _LIBCPP_NO_RTTI
1607};
1608
1609template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1610__base<_Rp(_ArgTypes...)>*
1611__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__clone() const
1612{
1613    typedef allocator_traits<_Alloc> __alloc_traits;
1614    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
1615    _Ap __a(__f_.__allocator());
1616    typedef __allocator_destructor<_Ap> _Dp;
1617    unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
1618    ::new ((void*)__hold.get()) __func(__f_.__target(), _Alloc(__a));
1619    return __hold.release();
1620}
1621
1622template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1623void
1624__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__clone(__base<_Rp(_ArgTypes...)>* __p) const
1625{
1626    ::new (__p) __func(__f_.__target(), __f_.__allocator());
1627}
1628
1629template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1630void
1631__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy() _NOEXCEPT
1632{
1633    __f_.destroy();
1634}
1635
1636template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1637void
1638__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate() _NOEXCEPT
1639{
1640    typedef allocator_traits<_Alloc> __alloc_traits;
1641    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
1642    _Ap __a(__f_.__allocator());
1643    __f_.destroy();
1644    __a.deallocate(this, 1);
1645}
1646
1647template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1648_Rp
1649__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&& ... __arg)
1650{
1651    return __f_(_VSTD::forward<_ArgTypes>(__arg)...);
1652}
1653
1654#ifndef _LIBCPP_NO_RTTI
1655
1656template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1657const void*
1658__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::target(const type_info& __ti) const _NOEXCEPT
1659{
1660    if (__ti == typeid(_Fp))
1661        return &__f_.__target();
1662    return (const void*)0;
1663}
1664
1665template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1666const std::type_info&
1667__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::target_type() const _NOEXCEPT
1668{
1669    return typeid(_Fp);
1670}
1671
1672#endif  // _LIBCPP_NO_RTTI
1673
1674// __value_func creates a value-type from a __func.
1675
1676template <class _Fp> class __value_func;
1677
1678template <class _Rp, class... _ArgTypes> class __value_func<_Rp(_ArgTypes...)>
1679{
1680    typename aligned_storage<3 * sizeof(void*)>::type __buf_;
1681
1682    typedef __base<_Rp(_ArgTypes...)> __func;
1683    __func* __f_;
1684
1685    _LIBCPP_NO_CFI static __func* __as_base(void* p)
1686    {
1687        return reinterpret_cast<__func*>(p);
1688    }
1689
1690  public:
1691    _LIBCPP_INLINE_VISIBILITY
1692    __value_func() _NOEXCEPT : __f_(0) {}
1693
1694    template <class _Fp, class _Alloc>
1695    _LIBCPP_INLINE_VISIBILITY __value_func(_Fp&& __f, const _Alloc __a)
1696        : __f_(0)
1697    {
1698        typedef allocator_traits<_Alloc> __alloc_traits;
1699        typedef __function::__func<_Fp, _Alloc, _Rp(_ArgTypes...)> _Fun;
1700        typedef typename __rebind_alloc_helper<__alloc_traits, _Fun>::type
1701            _FunAlloc;
1702
1703        if (__function::__not_null(__f))
1704        {
1705            _FunAlloc __af(__a);
1706            if (sizeof(_Fun) <= sizeof(__buf_) &&
1707                is_nothrow_copy_constructible<_Fp>::value &&
1708                is_nothrow_copy_constructible<_FunAlloc>::value)
1709            {
1710                __f_ =
1711                    ::new ((void*)&__buf_) _Fun(_VSTD::move(__f), _Alloc(__af));
1712            }
1713            else
1714            {
1715                typedef __allocator_destructor<_FunAlloc> _Dp;
1716                unique_ptr<__func, _Dp> __hold(__af.allocate(1), _Dp(__af, 1));
1717                ::new ((void*)__hold.get()) _Fun(_VSTD::move(__f), _Alloc(__a));
1718                __f_ = __hold.release();
1719            }
1720        }
1721    }
1722
1723    _LIBCPP_INLINE_VISIBILITY
1724    __value_func(const __value_func& __f)
1725    {
1726        if (__f.__f_ == 0)
1727            __f_ = 0;
1728        else if ((void*)__f.__f_ == &__f.__buf_)
1729        {
1730            __f_ = __as_base(&__buf_);
1731            __f.__f_->__clone(__f_);
1732        }
1733        else
1734            __f_ = __f.__f_->__clone();
1735    }
1736
1737    _LIBCPP_INLINE_VISIBILITY
1738    __value_func(__value_func&& __f) _NOEXCEPT
1739    {
1740        if (__f.__f_ == 0)
1741            __f_ = 0;
1742        else if ((void*)__f.__f_ == &__f.__buf_)
1743        {
1744            __f_ = __as_base(&__buf_);
1745            __f.__f_->__clone(__f_);
1746        }
1747        else
1748        {
1749            __f_ = __f.__f_;
1750            __f.__f_ = 0;
1751        }
1752    }
1753
1754    _LIBCPP_INLINE_VISIBILITY
1755    ~__value_func()
1756    {
1757        if ((void*)__f_ == &__buf_)
1758            __f_->destroy();
1759        else if (__f_)
1760            __f_->destroy_deallocate();
1761    }
1762
1763    _LIBCPP_INLINE_VISIBILITY
1764    __value_func& operator=(__value_func&& __f)
1765    {
1766        *this = nullptr;
1767        if (__f.__f_ == 0)
1768            __f_ = 0;
1769        else if ((void*)__f.__f_ == &__f.__buf_)
1770        {
1771            __f_ = __as_base(&__buf_);
1772            __f.__f_->__clone(__f_);
1773        }
1774        else
1775        {
1776            __f_ = __f.__f_;
1777            __f.__f_ = 0;
1778        }
1779        return *this;
1780    }
1781
1782    _LIBCPP_INLINE_VISIBILITY
1783    __value_func& operator=(nullptr_t)
1784    {
1785        __func* __f = __f_;
1786        __f_ = 0;
1787        if ((void*)__f == &__buf_)
1788            __f->destroy();
1789        else if (__f)
1790            __f->destroy_deallocate();
1791        return *this;
1792    }
1793
1794    _LIBCPP_INLINE_VISIBILITY
1795    _Rp operator()(_ArgTypes&&... __args) const
1796    {
1797        if (__f_ == 0)
1798            __throw_bad_function_call();
1799        return (*__f_)(_VSTD::forward<_ArgTypes>(__args)...);
1800    }
1801
1802    _LIBCPP_INLINE_VISIBILITY
1803    void swap(__value_func& __f) _NOEXCEPT
1804    {
1805        if (&__f == this)
1806            return;
1807        if ((void*)__f_ == &__buf_ && (void*)__f.__f_ == &__f.__buf_)
1808        {
1809            typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
1810            __func* __t = __as_base(&__tempbuf);
1811            __f_->__clone(__t);
1812            __f_->destroy();
1813            __f_ = 0;
1814            __f.__f_->__clone(__as_base(&__buf_));
1815            __f.__f_->destroy();
1816            __f.__f_ = 0;
1817            __f_ = __as_base(&__buf_);
1818            __t->__clone(__as_base(&__f.__buf_));
1819            __t->destroy();
1820            __f.__f_ = __as_base(&__f.__buf_);
1821        }
1822        else if ((void*)__f_ == &__buf_)
1823        {
1824            __f_->__clone(__as_base(&__f.__buf_));
1825            __f_->destroy();
1826            __f_ = __f.__f_;
1827            __f.__f_ = __as_base(&__f.__buf_);
1828        }
1829        else if ((void*)__f.__f_ == &__f.__buf_)
1830        {
1831            __f.__f_->__clone(__as_base(&__buf_));
1832            __f.__f_->destroy();
1833            __f.__f_ = __f_;
1834            __f_ = __as_base(&__buf_);
1835        }
1836        else
1837            _VSTD::swap(__f_, __f.__f_);
1838    }
1839
1840    _LIBCPP_INLINE_VISIBILITY
1841    _LIBCPP_EXPLICIT operator bool() const _NOEXCEPT { return __f_ != 0; }
1842
1843#ifndef _LIBCPP_NO_RTTI
1844    _LIBCPP_INLINE_VISIBILITY
1845    const std::type_info& target_type() const _NOEXCEPT
1846    {
1847        if (__f_ == 0)
1848            return typeid(void);
1849        return __f_->target_type();
1850    }
1851
1852    template <typename _Tp>
1853    _LIBCPP_INLINE_VISIBILITY const _Tp* target() const _NOEXCEPT
1854    {
1855        if (__f_ == 0)
1856            return 0;
1857        return (const _Tp*)__f_->target(typeid(_Tp));
1858    }
1859#endif // _LIBCPP_NO_RTTI
1860};
1861
1862// Storage for a functor object, to be used with __policy to manage copy and
1863// destruction.
1864union __policy_storage
1865{
1866    mutable char __small[sizeof(void*) * 2];
1867    void* __large;
1868};
1869
1870// True if _Fun can safely be held in __policy_storage.__small.
1871template <typename _Fun>
1872struct __use_small_storage
1873    : public _VSTD::integral_constant<
1874          bool, sizeof(_Fun) <= sizeof(__policy_storage) &&
1875                    alignof(_Fun) <= alignof(__policy_storage) &&
1876                    _VSTD::is_trivially_copy_constructible<_Fun>::value &&
1877                    _VSTD::is_trivially_destructible<_Fun>::value> {};
1878
1879// Policy contains information about how to copy, destroy, and move the
1880// underlying functor. You can think of it as a vtable of sorts.
1881struct __policy
1882{
1883    // Used to copy or destroy __large values. null for trivial objects.
1884    void* (*const __clone)(const void*);
1885    void (*const __destroy)(void*);
1886
1887    // True if this is the null policy (no value).
1888    const bool __is_null;
1889
1890    // The target type. May be null if RTTI is disabled.
1891    const std::type_info* const __type_info;
1892
1893    // Returns a pointer to a static policy object suitable for the functor
1894    // type.
1895    template <typename _Fun>
1896    _LIBCPP_INLINE_VISIBILITY static const __policy* __create()
1897    {
1898        return __choose_policy<_Fun>(__use_small_storage<_Fun>());
1899    }
1900
1901    _LIBCPP_INLINE_VISIBILITY
1902    static const __policy* __create_empty()
1903    {
1904        static const _LIBCPP_CONSTEXPR __policy __policy_ = {nullptr, nullptr,
1905                                                             true,
1906#ifndef _LIBCPP_NO_RTTI
1907                                                             &typeid(void)
1908#else
1909                                                             nullptr
1910#endif
1911        };
1912        return &__policy_;
1913    }
1914
1915  private:
1916    template <typename _Fun> static void* __large_clone(const void* __s)
1917    {
1918        const _Fun* __f = static_cast<const _Fun*>(__s);
1919        return __f->__clone();
1920    }
1921
1922    template <typename _Fun> static void __large_destroy(void* __s)
1923    {
1924        typedef allocator_traits<typename _Fun::_Alloc> __alloc_traits;
1925        typedef typename __rebind_alloc_helper<__alloc_traits, _Fun>::type
1926            _FunAlloc;
1927        _Fun* __f = static_cast<_Fun*>(__s);
1928        _FunAlloc __a(__f->__allocator());
1929        __f->destroy();
1930        __a.deallocate(__f, 1);
1931    }
1932
1933    template <typename _Fun>
1934    _LIBCPP_INLINE_VISIBILITY static const __policy*
1935        __choose_policy(/* is_small = */ false_type)
1936    {
1937        static const _LIBCPP_CONSTEXPR __policy __policy_ = {
1938            &__large_clone<_Fun>, &__large_destroy<_Fun>, false,
1939#ifndef _LIBCPP_NO_RTTI
1940            &typeid(typename _Fun::_Target)
1941#else
1942            nullptr
1943#endif
1944        };
1945        return &__policy_;
1946    }
1947
1948    template <typename _Fun>
1949    _LIBCPP_INLINE_VISIBILITY static const __policy*
1950        __choose_policy(/* is_small = */ true_type)
1951    {
1952        static const _LIBCPP_CONSTEXPR __policy __policy_ = {
1953            nullptr, nullptr, false,
1954#ifndef _LIBCPP_NO_RTTI
1955            &typeid(typename _Fun::_Target)
1956#else
1957            nullptr
1958#endif
1959        };
1960        return &__policy_;
1961    }
1962};
1963
1964// Used to choose between perfect forwarding or pass-by-value. Pass-by-value is
1965// faster for types that can be passed in registers.
1966template <typename _Tp>
1967using __fast_forward =
1968    typename _VSTD::conditional<_VSTD::is_scalar<_Tp>::value, _Tp, _Tp&&>::type;
1969
1970// __policy_invoker calls an instance of __alloc_func held in __policy_storage.
1971
1972template <class _Fp> struct __policy_invoker;
1973
1974template <class _Rp, class... _ArgTypes>
1975struct __policy_invoker<_Rp(_ArgTypes...)>
1976{
1977    typedef _Rp (*__Call)(const __policy_storage*,
1978                          __fast_forward<_ArgTypes>...);
1979
1980    __Call __call_;
1981
1982    // Creates an invoker that throws bad_function_call.
1983    _LIBCPP_INLINE_VISIBILITY
1984    __policy_invoker() : __call_(&__call_empty) {}
1985
1986    // Creates an invoker that calls the given instance of __func.
1987    template <typename _Fun>
1988    _LIBCPP_INLINE_VISIBILITY static __policy_invoker __create()
1989    {
1990        return __policy_invoker(&__call_impl<_Fun>);
1991    }
1992
1993  private:
1994    _LIBCPP_INLINE_VISIBILITY
1995    explicit __policy_invoker(__Call __c) : __call_(__c) {}
1996
1997    static _Rp __call_empty(const __policy_storage*,
1998                            __fast_forward<_ArgTypes>...)
1999    {
2000        __throw_bad_function_call();
2001    }
2002
2003    template <typename _Fun>
2004    static _Rp __call_impl(const __policy_storage* __buf,
2005                           __fast_forward<_ArgTypes>... __args)
2006    {
2007        _Fun* __f = reinterpret_cast<_Fun*>(__use_small_storage<_Fun>::value
2008                                                ? &__buf->__small
2009                                                : __buf->__large);
2010        return (*__f)(_VSTD::forward<_ArgTypes>(__args)...);
2011    }
2012};
2013
2014// __policy_func uses a __policy and __policy_invoker to create a type-erased,
2015// copyable functor.
2016
2017template <class _Fp> class __policy_func;
2018
2019template <class _Rp, class... _ArgTypes> class __policy_func<_Rp(_ArgTypes...)>
2020{
2021    // Inline storage for small objects.
2022    __policy_storage __buf_;
2023
2024    // Calls the value stored in __buf_. This could technically be part of
2025    // policy, but storing it here eliminates a level of indirection inside
2026    // operator().
2027    typedef __function::__policy_invoker<_Rp(_ArgTypes...)> __invoker;
2028    __invoker __invoker_;
2029
2030    // The policy that describes how to move / copy / destroy __buf_. Never
2031    // null, even if the function is empty.
2032    const __policy* __policy_;
2033
2034  public:
2035    _LIBCPP_INLINE_VISIBILITY
2036    __policy_func() : __policy_(__policy::__create_empty()) {}
2037
2038    template <class _Fp, class _Alloc>
2039    _LIBCPP_INLINE_VISIBILITY __policy_func(_Fp&& __f, const _Alloc& __a)
2040        : __policy_(__policy::__create_empty())
2041    {
2042        typedef __alloc_func<_Fp, _Alloc, _Rp(_ArgTypes...)> _Fun;
2043        typedef allocator_traits<_Alloc> __alloc_traits;
2044        typedef typename __rebind_alloc_helper<__alloc_traits, _Fun>::type
2045            _FunAlloc;
2046
2047        if (__function::__not_null(__f))
2048        {
2049            __invoker_ = __invoker::template __create<_Fun>();
2050            __policy_ = __policy::__create<_Fun>();
2051
2052            _FunAlloc __af(__a);
2053            if (__use_small_storage<_Fun>())
2054            {
2055                ::new ((void*)&__buf_.__small)
2056                    _Fun(_VSTD::move(__f), _Alloc(__af));
2057            }
2058            else
2059            {
2060                typedef __allocator_destructor<_FunAlloc> _Dp;
2061                unique_ptr<_Fun, _Dp> __hold(__af.allocate(1), _Dp(__af, 1));
2062                ::new ((void*)__hold.get())
2063                    _Fun(_VSTD::move(__f), _Alloc(__af));
2064                __buf_.__large = __hold.release();
2065            }
2066        }
2067    }
2068
2069    _LIBCPP_INLINE_VISIBILITY
2070    __policy_func(const __policy_func& __f)
2071        : __buf_(__f.__buf_), __invoker_(__f.__invoker_),
2072          __policy_(__f.__policy_)
2073    {
2074        if (__policy_->__clone)
2075            __buf_.__large = __policy_->__clone(__f.__buf_.__large);
2076    }
2077
2078    _LIBCPP_INLINE_VISIBILITY
2079    __policy_func(__policy_func&& __f)
2080        : __buf_(__f.__buf_), __invoker_(__f.__invoker_),
2081          __policy_(__f.__policy_)
2082    {
2083        if (__policy_->__destroy)
2084        {
2085            __f.__policy_ = __policy::__create_empty();
2086            __f.__invoker_ = __invoker();
2087        }
2088    }
2089
2090    _LIBCPP_INLINE_VISIBILITY
2091    ~__policy_func()
2092    {
2093        if (__policy_->__destroy)
2094            __policy_->__destroy(__buf_.__large);
2095    }
2096
2097    _LIBCPP_INLINE_VISIBILITY
2098    __policy_func& operator=(__policy_func&& __f)
2099    {
2100        *this = nullptr;
2101        __buf_ = __f.__buf_;
2102        __invoker_ = __f.__invoker_;
2103        __policy_ = __f.__policy_;
2104        __f.__policy_ = __policy::__create_empty();
2105        __f.__invoker_ = __invoker();
2106        return *this;
2107    }
2108
2109    _LIBCPP_INLINE_VISIBILITY
2110    __policy_func& operator=(nullptr_t)
2111    {
2112        const __policy* __p = __policy_;
2113        __policy_ = __policy::__create_empty();
2114        __invoker_ = __invoker();
2115        if (__p->__destroy)
2116            __p->__destroy(__buf_.__large);
2117        return *this;
2118    }
2119
2120    _LIBCPP_INLINE_VISIBILITY
2121    _Rp operator()(_ArgTypes&&... __args) const
2122    {
2123        return __invoker_.__call_(_VSTD::addressof(__buf_),
2124                                  _VSTD::forward<_ArgTypes>(__args)...);
2125    }
2126
2127    _LIBCPP_INLINE_VISIBILITY
2128    void swap(__policy_func& __f)
2129    {
2130        _VSTD::swap(__invoker_, __f.__invoker_);
2131        _VSTD::swap(__policy_, __f.__policy_);
2132        _VSTD::swap(__buf_, __f.__buf_);
2133    }
2134
2135    _LIBCPP_INLINE_VISIBILITY
2136    explicit operator bool() const _NOEXCEPT
2137    {
2138        return !__policy_->__is_null;
2139    }
2140
2141#ifndef _LIBCPP_NO_RTTI
2142    _LIBCPP_INLINE_VISIBILITY
2143    const std::type_info& target_type() const _NOEXCEPT
2144    {
2145        return *__policy_->__type_info;
2146    }
2147
2148    template <typename _Tp>
2149    _LIBCPP_INLINE_VISIBILITY const _Tp* target() const _NOEXCEPT
2150    {
2151        if (__policy_->__is_null || typeid(_Tp) != *__policy_->__type_info)
2152            return nullptr;
2153        if (__policy_->__clone) // Out of line storage.
2154            return reinterpret_cast<const _Tp*>(__buf_.__large);
2155        else
2156            return reinterpret_cast<const _Tp*>(&__buf_.__small);
2157    }
2158#endif // _LIBCPP_NO_RTTI
2159};
2160
2161}  // __function
2162
2163template<class _Rp, class ..._ArgTypes>
2164class _LIBCPP_TEMPLATE_VIS function<_Rp(_ArgTypes...)>
2165    : public __function::__maybe_derive_from_unary_function<_Rp(_ArgTypes...)>,
2166      public __function::__maybe_derive_from_binary_function<_Rp(_ArgTypes...)>
2167{
2168#ifndef _LIBCPP_ABI_OPTIMIZED_FUNCTION
2169    typedef __function::__value_func<_Rp(_ArgTypes...)> __func;
2170#else
2171    typedef __function::__policy_func<_Rp(_ArgTypes...)> __func;
2172#endif
2173
2174    __func __f_;
2175
2176    template <class _Fp, bool = __lazy_and<
2177        integral_constant<bool, !is_same<__uncvref_t<_Fp>, function>::value>,
2178        __invokable<_Fp&, _ArgTypes...>
2179    >::value>
2180    struct __callable;
2181    template <class _Fp>
2182        struct __callable<_Fp, true>
2183        {
2184            static const bool value = is_same<void, _Rp>::value ||
2185                is_convertible<typename __invoke_of<_Fp&, _ArgTypes...>::type,
2186                               _Rp>::value;
2187        };
2188    template <class _Fp>
2189        struct __callable<_Fp, false>
2190        {
2191            static const bool value = false;
2192        };
2193
2194  template <class _Fp>
2195  using _EnableIfCallable = typename enable_if<__callable<_Fp>::value>::type;
2196public:
2197    typedef _Rp result_type;
2198
2199    // construct/copy/destroy:
2200    _LIBCPP_INLINE_VISIBILITY
2201    function() _NOEXCEPT { }
2202    _LIBCPP_INLINE_VISIBILITY
2203    function(nullptr_t) _NOEXCEPT {}
2204    function(const function&);
2205    function(function&&) _NOEXCEPT;
2206    template<class _Fp, class = _EnableIfCallable<_Fp>>
2207    function(_Fp);
2208
2209#if _LIBCPP_STD_VER <= 14
2210    template<class _Alloc>
2211      _LIBCPP_INLINE_VISIBILITY
2212      function(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
2213    template<class _Alloc>
2214      _LIBCPP_INLINE_VISIBILITY
2215      function(allocator_arg_t, const _Alloc&, nullptr_t) _NOEXCEPT {}
2216    template<class _Alloc>
2217      function(allocator_arg_t, const _Alloc&, const function&);
2218    template<class _Alloc>
2219      function(allocator_arg_t, const _Alloc&, function&&);
2220    template<class _Fp, class _Alloc, class = _EnableIfCallable<_Fp>>
2221      function(allocator_arg_t, const _Alloc& __a, _Fp __f);
2222#endif
2223
2224    function& operator=(const function&);
2225    function& operator=(function&&) _NOEXCEPT;
2226    function& operator=(nullptr_t) _NOEXCEPT;
2227    template<class _Fp, class = _EnableIfCallable<_Fp>>
2228    function& operator=(_Fp&&);
2229
2230    ~function();
2231
2232    // function modifiers:
2233    void swap(function&) _NOEXCEPT;
2234
2235#if _LIBCPP_STD_VER <= 14
2236    template<class _Fp, class _Alloc>
2237      _LIBCPP_INLINE_VISIBILITY
2238      void assign(_Fp&& __f, const _Alloc& __a)
2239        {function(allocator_arg, __a, _VSTD::forward<_Fp>(__f)).swap(*this);}
2240#endif
2241
2242    // function capacity:
2243    _LIBCPP_INLINE_VISIBILITY
2244    _LIBCPP_EXPLICIT operator bool() const _NOEXCEPT {
2245      return static_cast<bool>(__f_);
2246    }
2247
2248    // deleted overloads close possible hole in the type system
2249    template<class _R2, class... _ArgTypes2>
2250      bool operator==(const function<_R2(_ArgTypes2...)>&) const = delete;
2251    template<class _R2, class... _ArgTypes2>
2252      bool operator!=(const function<_R2(_ArgTypes2...)>&) const = delete;
2253public:
2254    // function invocation:
2255    _Rp operator()(_ArgTypes...) const;
2256
2257#ifndef _LIBCPP_NO_RTTI
2258    // function target access:
2259    const std::type_info& target_type() const _NOEXCEPT;
2260    template <typename _Tp> _Tp* target() _NOEXCEPT;
2261    template <typename _Tp> const _Tp* target() const _NOEXCEPT;
2262#endif  // _LIBCPP_NO_RTTI
2263};
2264
2265template<class _Rp, class ..._ArgTypes>
2266function<_Rp(_ArgTypes...)>::function(const function& __f) : __f_(__f.__f_) {}
2267
2268#if _LIBCPP_STD_VER <= 14
2269template<class _Rp, class ..._ArgTypes>
2270template <class _Alloc>
2271function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc&,
2272                                     const function& __f) : __f_(__f.__f_) {}
2273#endif
2274
2275template <class _Rp, class... _ArgTypes>
2276function<_Rp(_ArgTypes...)>::function(function&& __f) _NOEXCEPT
2277    : __f_(_VSTD::move(__f.__f_)) {}
2278
2279#if _LIBCPP_STD_VER <= 14
2280template<class _Rp, class ..._ArgTypes>
2281template <class _Alloc>
2282function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc&,
2283                                      function&& __f)
2284    : __f_(_VSTD::move(__f.__f_)) {}
2285#endif
2286
2287template <class _Rp, class... _ArgTypes>
2288template <class _Fp, class>
2289function<_Rp(_ArgTypes...)>::function(_Fp __f)
2290    : __f_(_VSTD::move(__f), allocator<_Fp>()) {}
2291
2292#if _LIBCPP_STD_VER <= 14
2293template <class _Rp, class... _ArgTypes>
2294template <class _Fp, class _Alloc, class>
2295function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc& __a,
2296                                      _Fp __f)
2297    : __f_(_VSTD::move(__f), __a) {}
2298#endif
2299
2300template<class _Rp, class ..._ArgTypes>
2301function<_Rp(_ArgTypes...)>&
2302function<_Rp(_ArgTypes...)>::operator=(const function& __f)
2303{
2304    function(__f).swap(*this);
2305    return *this;
2306}
2307
2308template<class _Rp, class ..._ArgTypes>
2309function<_Rp(_ArgTypes...)>&
2310function<_Rp(_ArgTypes...)>::operator=(function&& __f) _NOEXCEPT
2311{
2312    __f_ = std::move(__f.__f_);
2313    return *this;
2314}
2315
2316template<class _Rp, class ..._ArgTypes>
2317function<_Rp(_ArgTypes...)>&
2318function<_Rp(_ArgTypes...)>::operator=(nullptr_t) _NOEXCEPT
2319{
2320    __f_ = nullptr;
2321    return *this;
2322}
2323
2324template<class _Rp, class ..._ArgTypes>
2325template <class _Fp, class>
2326function<_Rp(_ArgTypes...)>&
2327function<_Rp(_ArgTypes...)>::operator=(_Fp&& __f)
2328{
2329    function(_VSTD::forward<_Fp>(__f)).swap(*this);
2330    return *this;
2331}
2332
2333template<class _Rp, class ..._ArgTypes>
2334function<_Rp(_ArgTypes...)>::~function() {}
2335
2336template<class _Rp, class ..._ArgTypes>
2337void
2338function<_Rp(_ArgTypes...)>::swap(function& __f) _NOEXCEPT
2339{
2340    __f_.swap(__f.__f_);
2341}
2342
2343template<class _Rp, class ..._ArgTypes>
2344_Rp
2345function<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __arg) const
2346{
2347    return __f_(_VSTD::forward<_ArgTypes>(__arg)...);
2348}
2349
2350#ifndef _LIBCPP_NO_RTTI
2351
2352template<class _Rp, class ..._ArgTypes>
2353const std::type_info&
2354function<_Rp(_ArgTypes...)>::target_type() const _NOEXCEPT
2355{
2356    return __f_.target_type();
2357}
2358
2359template<class _Rp, class ..._ArgTypes>
2360template <typename _Tp>
2361_Tp*
2362function<_Rp(_ArgTypes...)>::target() _NOEXCEPT
2363{
2364    return (_Tp*)(__f_.template target<_Tp>());
2365}
2366
2367template<class _Rp, class ..._ArgTypes>
2368template <typename _Tp>
2369const _Tp*
2370function<_Rp(_ArgTypes...)>::target() const _NOEXCEPT
2371{
2372    return __f_.template target<_Tp>();
2373}
2374
2375#endif  // _LIBCPP_NO_RTTI
2376
2377template <class _Rp, class... _ArgTypes>
2378inline _LIBCPP_INLINE_VISIBILITY
2379bool
2380operator==(const function<_Rp(_ArgTypes...)>& __f, nullptr_t) _NOEXCEPT {return !__f;}
2381
2382template <class _Rp, class... _ArgTypes>
2383inline _LIBCPP_INLINE_VISIBILITY
2384bool
2385operator==(nullptr_t, const function<_Rp(_ArgTypes...)>& __f) _NOEXCEPT {return !__f;}
2386
2387template <class _Rp, class... _ArgTypes>
2388inline _LIBCPP_INLINE_VISIBILITY
2389bool
2390operator!=(const function<_Rp(_ArgTypes...)>& __f, nullptr_t) _NOEXCEPT {return (bool)__f;}
2391
2392template <class _Rp, class... _ArgTypes>
2393inline _LIBCPP_INLINE_VISIBILITY
2394bool
2395operator!=(nullptr_t, const function<_Rp(_ArgTypes...)>& __f) _NOEXCEPT {return (bool)__f;}
2396
2397template <class _Rp, class... _ArgTypes>
2398inline _LIBCPP_INLINE_VISIBILITY
2399void
2400swap(function<_Rp(_ArgTypes...)>& __x, function<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
2401{return __x.swap(__y);}
2402
2403#else // _LIBCPP_CXX03_LANG
2404
2405#include <__functional_03>
2406
2407#endif
2408
2409////////////////////////////////////////////////////////////////////////////////
2410//                                  BIND
2411//==============================================================================
2412
2413template<class _Tp> struct __is_bind_expression : public false_type {};
2414template<class _Tp> struct _LIBCPP_TEMPLATE_VIS is_bind_expression
2415    : public __is_bind_expression<typename remove_cv<_Tp>::type> {};
2416
2417#if _LIBCPP_STD_VER > 14
2418template <class _Tp>
2419_LIBCPP_INLINE_VAR constexpr size_t is_bind_expression_v = is_bind_expression<_Tp>::value;
2420#endif
2421
2422template<class _Tp> struct __is_placeholder : public integral_constant<int, 0> {};
2423template<class _Tp> struct _LIBCPP_TEMPLATE_VIS is_placeholder
2424    : public __is_placeholder<typename remove_cv<_Tp>::type> {};
2425
2426#if _LIBCPP_STD_VER > 14
2427template <class _Tp>
2428_LIBCPP_INLINE_VAR constexpr size_t is_placeholder_v = is_placeholder<_Tp>::value;
2429#endif
2430
2431namespace placeholders
2432{
2433
2434template <int _Np> struct __ph {};
2435
2436#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
2437_LIBCPP_FUNC_VIS extern const __ph<1>   _1;
2438_LIBCPP_FUNC_VIS extern const __ph<2>   _2;
2439_LIBCPP_FUNC_VIS extern const __ph<3>   _3;
2440_LIBCPP_FUNC_VIS extern const __ph<4>   _4;
2441_LIBCPP_FUNC_VIS extern const __ph<5>   _5;
2442_LIBCPP_FUNC_VIS extern const __ph<6>   _6;
2443_LIBCPP_FUNC_VIS extern const __ph<7>   _7;
2444_LIBCPP_FUNC_VIS extern const __ph<8>   _8;
2445_LIBCPP_FUNC_VIS extern const __ph<9>   _9;
2446_LIBCPP_FUNC_VIS extern const __ph<10> _10;
2447#else
2448/* _LIBCPP_INLINE_VAR */ constexpr __ph<1>   _1{};
2449/* _LIBCPP_INLINE_VAR */ constexpr __ph<2>   _2{};
2450/* _LIBCPP_INLINE_VAR */ constexpr __ph<3>   _3{};
2451/* _LIBCPP_INLINE_VAR */ constexpr __ph<4>   _4{};
2452/* _LIBCPP_INLINE_VAR */ constexpr __ph<5>   _5{};
2453/* _LIBCPP_INLINE_VAR */ constexpr __ph<6>   _6{};
2454/* _LIBCPP_INLINE_VAR */ constexpr __ph<7>   _7{};
2455/* _LIBCPP_INLINE_VAR */ constexpr __ph<8>   _8{};
2456/* _LIBCPP_INLINE_VAR */ constexpr __ph<9>   _9{};
2457/* _LIBCPP_INLINE_VAR */ constexpr __ph<10> _10{};
2458#endif // defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
2459
2460}  // placeholders
2461
2462template<int _Np>
2463struct __is_placeholder<placeholders::__ph<_Np> >
2464    : public integral_constant<int, _Np> {};
2465
2466
2467#ifndef _LIBCPP_CXX03_LANG
2468
2469template <class _Tp, class _Uj>
2470inline _LIBCPP_INLINE_VISIBILITY
2471_Tp&
2472__mu(reference_wrapper<_Tp> __t, _Uj&)
2473{
2474    return __t.get();
2475}
2476
2477template <class _Ti, class ..._Uj, size_t ..._Indx>
2478inline _LIBCPP_INLINE_VISIBILITY
2479typename __invoke_of<_Ti&, _Uj...>::type
2480__mu_expand(_Ti& __ti, tuple<_Uj...>& __uj, __tuple_indices<_Indx...>)
2481{
2482    return __ti(_VSTD::forward<_Uj>(_VSTD::get<_Indx>(__uj))...);
2483}
2484
2485template <class _Ti, class ..._Uj>
2486inline _LIBCPP_INLINE_VISIBILITY
2487typename __lazy_enable_if
2488<
2489    is_bind_expression<_Ti>::value,
2490    __invoke_of<_Ti&, _Uj...>
2491>::type
2492__mu(_Ti& __ti, tuple<_Uj...>& __uj)
2493{
2494    typedef typename __make_tuple_indices<sizeof...(_Uj)>::type __indices;
2495    return  __mu_expand(__ti, __uj, __indices());
2496}
2497
2498template <bool IsPh, class _Ti, class _Uj>
2499struct __mu_return2 {};
2500
2501template <class _Ti, class _Uj>
2502struct __mu_return2<true, _Ti, _Uj>
2503{
2504    typedef typename tuple_element<is_placeholder<_Ti>::value - 1, _Uj>::type type;
2505};
2506
2507template <class _Ti, class _Uj>
2508inline _LIBCPP_INLINE_VISIBILITY
2509typename enable_if
2510<
2511    0 < is_placeholder<_Ti>::value,
2512    typename __mu_return2<0 < is_placeholder<_Ti>::value, _Ti, _Uj>::type
2513>::type
2514__mu(_Ti&, _Uj& __uj)
2515{
2516    const size_t _Indx = is_placeholder<_Ti>::value - 1;
2517    return _VSTD::forward<typename tuple_element<_Indx, _Uj>::type>(_VSTD::get<_Indx>(__uj));
2518}
2519
2520template <class _Ti, class _Uj>
2521inline _LIBCPP_INLINE_VISIBILITY
2522typename enable_if
2523<
2524    !is_bind_expression<_Ti>::value &&
2525    is_placeholder<_Ti>::value == 0 &&
2526    !__is_reference_wrapper<_Ti>::value,
2527    _Ti&
2528>::type
2529__mu(_Ti& __ti, _Uj&)
2530{
2531    return __ti;
2532}
2533
2534template <class _Ti, bool IsReferenceWrapper, bool IsBindEx, bool IsPh,
2535          class _TupleUj>
2536struct __mu_return_impl;
2537
2538template <bool _Invokable, class _Ti, class ..._Uj>
2539struct __mu_return_invokable  // false
2540{
2541    typedef __nat type;
2542};
2543
2544template <class _Ti, class ..._Uj>
2545struct __mu_return_invokable<true, _Ti, _Uj...>
2546{
2547    typedef typename __invoke_of<_Ti&, _Uj...>::type type;
2548};
2549
2550template <class _Ti, class ..._Uj>
2551struct __mu_return_impl<_Ti, false, true, false, tuple<_Uj...> >
2552    : public __mu_return_invokable<__invokable<_Ti&, _Uj...>::value, _Ti, _Uj...>
2553{
2554};
2555
2556template <class _Ti, class _TupleUj>
2557struct __mu_return_impl<_Ti, false, false, true, _TupleUj>
2558{
2559    typedef typename tuple_element<is_placeholder<_Ti>::value - 1,
2560                                   _TupleUj>::type&& type;
2561};
2562
2563template <class _Ti, class _TupleUj>
2564struct __mu_return_impl<_Ti, true, false, false, _TupleUj>
2565{
2566    typedef typename _Ti::type& type;
2567};
2568
2569template <class _Ti, class _TupleUj>
2570struct __mu_return_impl<_Ti, false, false, false, _TupleUj>
2571{
2572    typedef _Ti& type;
2573};
2574
2575template <class _Ti, class _TupleUj>
2576struct __mu_return
2577    : public __mu_return_impl<_Ti,
2578                              __is_reference_wrapper<_Ti>::value,
2579                              is_bind_expression<_Ti>::value,
2580                              0 < is_placeholder<_Ti>::value &&
2581                              is_placeholder<_Ti>::value <= tuple_size<_TupleUj>::value,
2582                              _TupleUj>
2583{
2584};
2585
2586template <class _Fp, class _BoundArgs, class _TupleUj>
2587struct __is_valid_bind_return
2588{
2589    static const bool value = false;
2590};
2591
2592template <class _Fp, class ..._BoundArgs, class _TupleUj>
2593struct __is_valid_bind_return<_Fp, tuple<_BoundArgs...>, _TupleUj>
2594{
2595    static const bool value = __invokable<_Fp,
2596                    typename __mu_return<_BoundArgs, _TupleUj>::type...>::value;
2597};
2598
2599template <class _Fp, class ..._BoundArgs, class _TupleUj>
2600struct __is_valid_bind_return<_Fp, const tuple<_BoundArgs...>, _TupleUj>
2601{
2602    static const bool value = __invokable<_Fp,
2603                    typename __mu_return<const _BoundArgs, _TupleUj>::type...>::value;
2604};
2605
2606template <class _Fp, class _BoundArgs, class _TupleUj,
2607          bool = __is_valid_bind_return<_Fp, _BoundArgs, _TupleUj>::value>
2608struct __bind_return;
2609
2610template <class _Fp, class ..._BoundArgs, class _TupleUj>
2611struct __bind_return<_Fp, tuple<_BoundArgs...>, _TupleUj, true>
2612{
2613    typedef typename __invoke_of
2614    <
2615        _Fp&,
2616        typename __mu_return
2617        <
2618            _BoundArgs,
2619            _TupleUj
2620        >::type...
2621    >::type type;
2622};
2623
2624template <class _Fp, class ..._BoundArgs, class _TupleUj>
2625struct __bind_return<_Fp, const tuple<_BoundArgs...>, _TupleUj, true>
2626{
2627    typedef typename __invoke_of
2628    <
2629        _Fp&,
2630        typename __mu_return
2631        <
2632            const _BoundArgs,
2633            _TupleUj
2634        >::type...
2635    >::type type;
2636};
2637
2638template <class _Fp, class _BoundArgs, size_t ..._Indx, class _Args>
2639inline _LIBCPP_INLINE_VISIBILITY
2640typename __bind_return<_Fp, _BoundArgs, _Args>::type
2641__apply_functor(_Fp& __f, _BoundArgs& __bound_args, __tuple_indices<_Indx...>,
2642                _Args&& __args)
2643{
2644    return _VSTD::__invoke(__f, _VSTD::__mu(_VSTD::get<_Indx>(__bound_args), __args)...);
2645}
2646
2647template<class _Fp, class ..._BoundArgs>
2648class __bind
2649    : public __weak_result_type<typename decay<_Fp>::type>
2650{
2651protected:
2652    typedef typename decay<_Fp>::type _Fd;
2653    typedef tuple<typename decay<_BoundArgs>::type...> _Td;
2654private:
2655    _Fd __f_;
2656    _Td __bound_args_;
2657
2658    typedef typename __make_tuple_indices<sizeof...(_BoundArgs)>::type __indices;
2659public:
2660    template <class _Gp, class ..._BA,
2661              class = typename enable_if
2662                               <
2663                                  is_constructible<_Fd, _Gp>::value &&
2664                                  !is_same<typename remove_reference<_Gp>::type,
2665                                           __bind>::value
2666                               >::type>
2667      _LIBCPP_INLINE_VISIBILITY
2668      explicit __bind(_Gp&& __f, _BA&& ...__bound_args)
2669        : __f_(_VSTD::forward<_Gp>(__f)),
2670          __bound_args_(_VSTD::forward<_BA>(__bound_args)...) {}
2671
2672    template <class ..._Args>
2673        _LIBCPP_INLINE_VISIBILITY
2674        typename __bind_return<_Fd, _Td, tuple<_Args&&...> >::type
2675        operator()(_Args&& ...__args)
2676        {
2677            return _VSTD::__apply_functor(__f_, __bound_args_, __indices(),
2678                                  tuple<_Args&&...>(_VSTD::forward<_Args>(__args)...));
2679        }
2680
2681    template <class ..._Args>
2682        _LIBCPP_INLINE_VISIBILITY
2683        typename __bind_return<const _Fd, const _Td, tuple<_Args&&...> >::type
2684        operator()(_Args&& ...__args) const
2685        {
2686            return _VSTD::__apply_functor(__f_, __bound_args_, __indices(),
2687                                   tuple<_Args&&...>(_VSTD::forward<_Args>(__args)...));
2688        }
2689};
2690
2691template<class _Fp, class ..._BoundArgs>
2692struct __is_bind_expression<__bind<_Fp, _BoundArgs...> > : public true_type {};
2693
2694template<class _Rp, class _Fp, class ..._BoundArgs>
2695class __bind_r
2696    : public __bind<_Fp, _BoundArgs...>
2697{
2698    typedef __bind<_Fp, _BoundArgs...> base;
2699    typedef typename base::_Fd _Fd;
2700    typedef typename base::_Td _Td;
2701public:
2702    typedef _Rp result_type;
2703
2704
2705    template <class _Gp, class ..._BA,
2706              class = typename enable_if
2707                               <
2708                                  is_constructible<_Fd, _Gp>::value &&
2709                                  !is_same<typename remove_reference<_Gp>::type,
2710                                           __bind_r>::value
2711                               >::type>
2712      _LIBCPP_INLINE_VISIBILITY
2713      explicit __bind_r(_Gp&& __f, _BA&& ...__bound_args)
2714        : base(_VSTD::forward<_Gp>(__f),
2715               _VSTD::forward<_BA>(__bound_args)...) {}
2716
2717    template <class ..._Args>
2718        _LIBCPP_INLINE_VISIBILITY
2719        typename enable_if
2720        <
2721            is_convertible<typename __bind_return<_Fd, _Td, tuple<_Args&&...> >::type,
2722                           result_type>::value || is_void<_Rp>::value,
2723            result_type
2724        >::type
2725        operator()(_Args&& ...__args)
2726        {
2727            typedef __invoke_void_return_wrapper<_Rp> _Invoker;
2728            return _Invoker::__call(static_cast<base&>(*this), _VSTD::forward<_Args>(__args)...);
2729        }
2730
2731    template <class ..._Args>
2732        _LIBCPP_INLINE_VISIBILITY
2733        typename enable_if
2734        <
2735            is_convertible<typename __bind_return<const _Fd, const _Td, tuple<_Args&&...> >::type,
2736                           result_type>::value || is_void<_Rp>::value,
2737            result_type
2738        >::type
2739        operator()(_Args&& ...__args) const
2740        {
2741            typedef __invoke_void_return_wrapper<_Rp> _Invoker;
2742            return _Invoker::__call(static_cast<base const&>(*this), _VSTD::forward<_Args>(__args)...);
2743        }
2744};
2745
2746template<class _Rp, class _Fp, class ..._BoundArgs>
2747struct __is_bind_expression<__bind_r<_Rp, _Fp, _BoundArgs...> > : public true_type {};
2748
2749template<class _Fp, class ..._BoundArgs>
2750inline _LIBCPP_INLINE_VISIBILITY
2751__bind<_Fp, _BoundArgs...>
2752bind(_Fp&& __f, _BoundArgs&&... __bound_args)
2753{
2754    typedef __bind<_Fp, _BoundArgs...> type;
2755    return type(_VSTD::forward<_Fp>(__f), _VSTD::forward<_BoundArgs>(__bound_args)...);
2756}
2757
2758template<class _Rp, class _Fp, class ..._BoundArgs>
2759inline _LIBCPP_INLINE_VISIBILITY
2760__bind_r<_Rp, _Fp, _BoundArgs...>
2761bind(_Fp&& __f, _BoundArgs&&... __bound_args)
2762{
2763    typedef __bind_r<_Rp, _Fp, _BoundArgs...> type;
2764    return type(_VSTD::forward<_Fp>(__f), _VSTD::forward<_BoundArgs>(__bound_args)...);
2765}
2766
2767#endif  // _LIBCPP_CXX03_LANG
2768
2769#if _LIBCPP_STD_VER > 14
2770
2771template <class _Fn, class ..._Args>
2772result_of_t<_Fn&&(_Args&&...)>
2773invoke(_Fn&& __f, _Args&&... __args)
2774    noexcept(noexcept(_VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...)))
2775{
2776    return _VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
2777}
2778
2779template <class _DecayFunc>
2780class _LIBCPP_TEMPLATE_VIS __not_fn_imp {
2781  _DecayFunc __fd;
2782
2783public:
2784    __not_fn_imp() = delete;
2785
2786    template <class ..._Args>
2787    _LIBCPP_INLINE_VISIBILITY
2788    auto operator()(_Args&& ...__args) &
2789            noexcept(noexcept(!_VSTD::invoke(__fd, _VSTD::forward<_Args>(__args)...)))
2790        -> decltype(          !_VSTD::invoke(__fd, _VSTD::forward<_Args>(__args)...))
2791        { return              !_VSTD::invoke(__fd, _VSTD::forward<_Args>(__args)...); }
2792
2793    template <class ..._Args>
2794    _LIBCPP_INLINE_VISIBILITY
2795    auto operator()(_Args&& ...__args) &&
2796            noexcept(noexcept(!_VSTD::invoke(_VSTD::move(__fd), _VSTD::forward<_Args>(__args)...)))
2797        -> decltype(          !_VSTD::invoke(_VSTD::move(__fd), _VSTD::forward<_Args>(__args)...))
2798        { return              !_VSTD::invoke(_VSTD::move(__fd), _VSTD::forward<_Args>(__args)...); }
2799
2800    template <class ..._Args>
2801    _LIBCPP_INLINE_VISIBILITY
2802    auto operator()(_Args&& ...__args) const&
2803            noexcept(noexcept(!_VSTD::invoke(__fd, _VSTD::forward<_Args>(__args)...)))
2804        -> decltype(          !_VSTD::invoke(__fd, _VSTD::forward<_Args>(__args)...))
2805        { return              !_VSTD::invoke(__fd, _VSTD::forward<_Args>(__args)...); }
2806
2807
2808    template <class ..._Args>
2809    _LIBCPP_INLINE_VISIBILITY
2810    auto operator()(_Args&& ...__args) const&&
2811            noexcept(noexcept(!_VSTD::invoke(_VSTD::move(__fd), _VSTD::forward<_Args>(__args)...)))
2812        -> decltype(          !_VSTD::invoke(_VSTD::move(__fd), _VSTD::forward<_Args>(__args)...))
2813        { return              !_VSTD::invoke(_VSTD::move(__fd), _VSTD::forward<_Args>(__args)...); }
2814
2815private:
2816    template <class _RawFunc,
2817              class = enable_if_t<!is_same<decay_t<_RawFunc>, __not_fn_imp>::value>>
2818    _LIBCPP_INLINE_VISIBILITY
2819    explicit __not_fn_imp(_RawFunc&& __rf)
2820        : __fd(_VSTD::forward<_RawFunc>(__rf)) {}
2821
2822    template <class _RawFunc>
2823    friend inline _LIBCPP_INLINE_VISIBILITY
2824    __not_fn_imp<decay_t<_RawFunc>> not_fn(_RawFunc&&);
2825};
2826
2827template <class _RawFunc>
2828inline _LIBCPP_INLINE_VISIBILITY
2829__not_fn_imp<decay_t<_RawFunc>> not_fn(_RawFunc&& __fn) {
2830    return __not_fn_imp<decay_t<_RawFunc>>(_VSTD::forward<_RawFunc>(__fn));
2831}
2832
2833#endif
2834
2835// struct hash<T*> in <memory>
2836
2837template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
2838pair<_ForwardIterator1, _ForwardIterator1> _LIBCPP_CONSTEXPR_AFTER_CXX11
2839__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
2840         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
2841         forward_iterator_tag, forward_iterator_tag)
2842{
2843    if (__first2 == __last2)
2844        return make_pair(__first1, __first1);  // Everything matches an empty sequence
2845    while (true)
2846    {
2847        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
2848        while (true)
2849        {
2850            if (__first1 == __last1)  // return __last1 if no element matches *__first2
2851                return make_pair(__last1, __last1);
2852            if (__pred(*__first1, *__first2))
2853                break;
2854            ++__first1;
2855        }
2856        // *__first1 matches *__first2, now match elements after here
2857        _ForwardIterator1 __m1 = __first1;
2858        _ForwardIterator2 __m2 = __first2;
2859        while (true)
2860        {
2861            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
2862                return make_pair(__first1, __m1);
2863            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
2864                return make_pair(__last1, __last1);
2865            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
2866            {
2867                ++__first1;
2868                break;
2869            }  // else there is a match, check next elements
2870        }
2871    }
2872}
2873
2874template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
2875_LIBCPP_CONSTEXPR_AFTER_CXX11
2876pair<_RandomAccessIterator1, _RandomAccessIterator1>
2877__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
2878         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
2879           random_access_iterator_tag, random_access_iterator_tag)
2880{
2881    typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
2882    typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
2883    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
2884    const _D2 __len2 = __last2 - __first2;
2885    if (__len2 == 0)
2886        return make_pair(__first1, __first1);
2887    const _D1 __len1 = __last1 - __first1;
2888    if (__len1 < __len2)
2889        return make_pair(__last1, __last1);
2890    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
2891
2892    while (true)
2893    {
2894        while (true)
2895        {
2896            if (__first1 == __s)
2897                return make_pair(__last1, __last1);
2898            if (__pred(*__first1, *__first2))
2899                break;
2900            ++__first1;
2901        }
2902
2903        _RandomAccessIterator1 __m1 = __first1;
2904        _RandomAccessIterator2 __m2 = __first2;
2905         while (true)
2906         {
2907             if (++__m2 == __last2)
2908                 return make_pair(__first1, __first1 + __len2);
2909             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
2910             if (!__pred(*__m1, *__m2))
2911             {
2912                 ++__first1;
2913                 break;
2914             }
2915         }
2916    }
2917}
2918
2919#if _LIBCPP_STD_VER > 14
2920
2921// default searcher
2922template<class _ForwardIterator, class _BinaryPredicate = equal_to<>>
2923class _LIBCPP_TYPE_VIS default_searcher {
2924public:
2925    _LIBCPP_INLINE_VISIBILITY
2926    default_searcher(_ForwardIterator __f, _ForwardIterator __l,
2927                       _BinaryPredicate __p = _BinaryPredicate())
2928        : __first_(__f), __last_(__l), __pred_(__p) {}
2929
2930    template <typename _ForwardIterator2>
2931    _LIBCPP_INLINE_VISIBILITY
2932    pair<_ForwardIterator2, _ForwardIterator2>
2933    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
2934    {
2935        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
2936            typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category(),
2937            typename _VSTD::iterator_traits<_ForwardIterator2>::iterator_category());
2938    }
2939
2940private:
2941    _ForwardIterator __first_;
2942    _ForwardIterator __last_;
2943    _BinaryPredicate __pred_;
2944    };
2945
2946#endif // _LIBCPP_STD_VER > 14
2947
2948#if _LIBCPP_STD_VER > 17
2949template <class _Tp>
2950using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
2951
2952template <class _Tp>
2953using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
2954#endif // > C++17
2955
2956template <class _Container, class _Predicate>
2957inline void __libcpp_erase_if_container( _Container& __c, _Predicate __pred)
2958{
2959	for (typename _Container::iterator __iter = __c.begin(), __last = __c.end(); __iter != __last;)
2960	{
2961		if (__pred(*__iter))
2962			__iter = __c.erase(__iter);
2963		else
2964			++__iter;
2965	}
2966}
2967
2968_LIBCPP_END_NAMESPACE_STD
2969
2970#endif  // _LIBCPP_FUNCTIONAL
2971