1 // unique_ptr implementation -*- C++ -*-
2 
3 // Copyright (C) 2008-2014 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file bits/unique_ptr.h
26  *  This is an internal header file, included by other library headers.
27  *  Do not attempt to use it directly. @headername{memory}
28  */
29 
30 #ifndef _UNIQUE_PTR_H
31 #define _UNIQUE_PTR_H 1
32 
33 #include <bits/c++config.h>
34 #include <debug/debug.h>
35 #include <type_traits>
36 #include <utility>
37 #include <tuple>
38 
_GLIBCXX_VISIBILITY(default)39 namespace std _GLIBCXX_VISIBILITY(default)
40 {
41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 
43   /**
44    * @addtogroup pointer_abstractions
45    * @{
46    */
47 
48 #if _GLIBCXX_USE_DEPRECATED
49   template<typename> class auto_ptr;
50 #endif
51 
52   /// Primary template of default_delete, used by unique_ptr
53   template<typename _Tp>
54     struct default_delete
55     {
56       /// Default constructor
57       constexpr default_delete() noexcept = default;
58 
59       /** @brief Converting constructor.
60        *
61        * Allows conversion from a deleter for arrays of another type, @p _Up,
62        * only if @p _Up* is convertible to @p _Tp*.
63        */
64       template<typename _Up, typename = typename
65 	       enable_if<is_convertible<_Up*, _Tp*>::value>::type>
66         default_delete(const default_delete<_Up>&) noexcept { }
67 
68       /// Calls @c delete @p __ptr
69       void
70       operator()(_Tp* __ptr) const
71       {
72 	static_assert(!is_void<_Tp>::value,
73 		      "can't delete pointer to incomplete type");
74 	static_assert(sizeof(_Tp)>0,
75 		      "can't delete pointer to incomplete type");
76 	delete __ptr;
77       }
78     };
79 
80   // _GLIBCXX_RESOLVE_LIB_DEFECTS
81   // DR 740 - omit specialization for array objects with a compile time length
82   /// Specialization for arrays, default_delete.
83   template<typename _Tp>
84     struct default_delete<_Tp[]>
85     {
86     private:
87       template<typename _Up>
88 	using __remove_cv = typename remove_cv<_Up>::type;
89 
90       // Like is_base_of<_Tp, _Up> but false if unqualified types are the same
91       template<typename _Up>
92 	using __is_derived_Tp
93 	  = __and_< is_base_of<_Tp, _Up>,
94 		    __not_<is_same<__remove_cv<_Tp>, __remove_cv<_Up>>> >;
95 
96     public:
97       /// Default constructor
98       constexpr default_delete() noexcept = default;
99 
100       /** @brief Converting constructor.
101        *
102        * Allows conversion from a deleter for arrays of another type, such as
103        * a const-qualified version of @p _Tp.
104        *
105        * Conversions from types derived from @c _Tp are not allowed because
106        * it is unsafe to @c delete[] an array of derived types through a
107        * pointer to the base type.
108        */
109       template<typename _Up, typename = typename
110 	       enable_if<!__is_derived_Tp<_Up>::value>::type>
111         default_delete(const default_delete<_Up[]>&) noexcept { }
112 
113       /// Calls @c delete[] @p __ptr
114       void
115       operator()(_Tp* __ptr) const
116       {
117 	static_assert(sizeof(_Tp)>0,
118 		      "can't delete pointer to incomplete type");
119 	delete [] __ptr;
120       }
121 
122       template<typename _Up>
123 	typename enable_if<__is_derived_Tp<_Up>::value>::type
124 	operator()(_Up*) const = delete;
125     };
126 
127   /// 20.7.1.2 unique_ptr for single objects.
128   template <typename _Tp, typename _Dp = default_delete<_Tp> >
129     class unique_ptr
130     {
131       // use SFINAE to determine whether _Del::pointer exists
132       class _Pointer
133       {
134 	template<typename _Up>
135 	  static typename _Up::pointer __test(typename _Up::pointer*);
136 
137 	template<typename _Up>
138 	  static _Tp* __test(...);
139 
140 	typedef typename remove_reference<_Dp>::type _Del;
141 
142       public:
143 	typedef decltype(__test<_Del>(0)) type;
144       };
145 
146       typedef std::tuple<typename _Pointer::type, _Dp>  __tuple_type;
147       __tuple_type                                      _M_t;
148 
149     public:
150       typedef typename _Pointer::type   pointer;
151       typedef _Tp                       element_type;
152       typedef _Dp                       deleter_type;
153 
154       // Constructors.
155 
156       /// Default constructor, creates a unique_ptr that owns nothing.
157       constexpr unique_ptr() noexcept
158       : _M_t()
159       { static_assert(!is_pointer<deleter_type>::value,
160 		     "constructed with null function pointer deleter"); }
161 
162       /** Takes ownership of a pointer.
163        *
164        * @param __p  A pointer to an object of @c element_type
165        *
166        * The deleter will be value-initialized.
167        */
168       explicit
169       unique_ptr(pointer __p) noexcept
170       : _M_t(__p, deleter_type())
171       { static_assert(!is_pointer<deleter_type>::value,
172 		     "constructed with null function pointer deleter"); }
173 
174       /** Takes ownership of a pointer.
175        *
176        * @param __p  A pointer to an object of @c element_type
177        * @param __d  A reference to a deleter.
178        *
179        * The deleter will be initialized with @p __d
180        */
181       unique_ptr(pointer __p,
182 	  typename conditional<is_reference<deleter_type>::value,
183 	    deleter_type, const deleter_type&>::type __d) noexcept
184       : _M_t(__p, __d) { }
185 
186       /** Takes ownership of a pointer.
187        *
188        * @param __p  A pointer to an object of @c element_type
189        * @param __d  An rvalue reference to a deleter.
190        *
191        * The deleter will be initialized with @p std::move(__d)
192        */
193       unique_ptr(pointer __p,
194 	  typename remove_reference<deleter_type>::type&& __d) noexcept
195       : _M_t(std::move(__p), std::move(__d))
196       { static_assert(!std::is_reference<deleter_type>::value,
197 		      "rvalue deleter bound to reference"); }
198 
199       /// Creates a unique_ptr that owns nothing.
200       constexpr unique_ptr(nullptr_t) noexcept : unique_ptr() { }
201 
202       // Move constructors.
203 
204       /// Move constructor.
205       unique_ptr(unique_ptr&& __u) noexcept
206       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
207 
208       /** @brief Converting constructor from another type
209        *
210        * Requires that the pointer owned by @p __u is convertible to the
211        * type of pointer owned by this object, @p __u does not own an array,
212        * and @p __u has a compatible deleter type.
213        */
214       template<typename _Up, typename _Ep, typename = _Require<
215 	       is_convertible<typename unique_ptr<_Up, _Ep>::pointer, pointer>,
216 	       __not_<is_array<_Up>>,
217 	       typename conditional<is_reference<_Dp>::value,
218 				    is_same<_Ep, _Dp>,
219 				    is_convertible<_Ep, _Dp>>::type>>
220 	unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
221 	: _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
222 	{ }
223 
224 #if _GLIBCXX_USE_DEPRECATED
225       /// Converting constructor from @c auto_ptr
226       template<typename _Up, typename = _Require<
227 	       is_convertible<_Up*, _Tp*>, is_same<_Dp, default_delete<_Tp>>>>
228 	unique_ptr(auto_ptr<_Up>&& __u) noexcept;
229 #endif
230 
231       /// Destructor, invokes the deleter if the stored pointer is not null.
232       ~unique_ptr() noexcept
233       {
234 	auto& __ptr = std::get<0>(_M_t);
235 	if (__ptr != nullptr)
236 	  get_deleter()(__ptr);
237 	__ptr = pointer();
238       }
239 
240       // Assignment.
241 
242       /** @brief Move assignment operator.
243        *
244        * @param __u  The object to transfer ownership from.
245        *
246        * Invokes the deleter first if this object owns a pointer.
247        */
248       unique_ptr&
249       operator=(unique_ptr&& __u) noexcept
250       {
251 	reset(__u.release());
252 	get_deleter() = std::forward<deleter_type>(__u.get_deleter());
253 	return *this;
254       }
255 
256       /** @brief Assignment from another type.
257        *
258        * @param __u  The object to transfer ownership from, which owns a
259        *             convertible pointer to a non-array object.
260        *
261        * Invokes the deleter first if this object owns a pointer.
262        */
263       template<typename _Up, typename _Ep>
264 	typename enable_if< __and_<
265 	  is_convertible<typename unique_ptr<_Up, _Ep>::pointer, pointer>,
266 	  __not_<is_array<_Up>>
267 	  >::value,
268 	  unique_ptr&>::type
269 	operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
270 	{
271 	  reset(__u.release());
272 	  get_deleter() = std::forward<_Ep>(__u.get_deleter());
273 	  return *this;
274 	}
275 
276       /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
277       unique_ptr&
278       operator=(nullptr_t) noexcept
279       {
280 	reset();
281 	return *this;
282       }
283 
284       // Observers.
285 
286       /// Dereference the stored pointer.
287       typename add_lvalue_reference<element_type>::type
288       operator*() const
289       {
290 	_GLIBCXX_DEBUG_ASSERT(get() != pointer());
291 	return *get();
292       }
293 
294       /// Return the stored pointer.
295       pointer
296       operator->() const noexcept
297       {
298 	_GLIBCXX_DEBUG_ASSERT(get() != pointer());
299 	return get();
300       }
301 
302       /// Return the stored pointer.
303       pointer
304       get() const noexcept
305       { return std::get<0>(_M_t); }
306 
307       /// Return a reference to the stored deleter.
308       deleter_type&
309       get_deleter() noexcept
310       { return std::get<1>(_M_t); }
311 
312       /// Return a reference to the stored deleter.
313       const deleter_type&
314       get_deleter() const noexcept
315       { return std::get<1>(_M_t); }
316 
317       /// Return @c true if the stored pointer is not null.
318       explicit operator bool() const noexcept
319       { return get() == pointer() ? false : true; }
320 
321       // Modifiers.
322 
323       /// Release ownership of any stored pointer.
324       pointer
325       release() noexcept
326       {
327 	pointer __p = get();
328 	std::get<0>(_M_t) = pointer();
329 	return __p;
330       }
331 
332       /** @brief Replace the stored pointer.
333        *
334        * @param __p  The new pointer to store.
335        *
336        * The deleter will be invoked if a pointer is already owned.
337        */
338       void
339       reset(pointer __p = pointer()) noexcept
340       {
341 	using std::swap;
342 	swap(std::get<0>(_M_t), __p);
343 	if (__p != pointer())
344 	  get_deleter()(__p);
345       }
346 
347       /// Exchange the pointer and deleter with another object.
348       void
349       swap(unique_ptr& __u) noexcept
350       {
351 	using std::swap;
352 	swap(_M_t, __u._M_t);
353       }
354 
355       // Disable copy from lvalue.
356       unique_ptr(const unique_ptr&) = delete;
357       unique_ptr& operator=(const unique_ptr&) = delete;
358   };
359 
360   /// 20.7.1.3 unique_ptr for array objects with a runtime length
361   // [unique.ptr.runtime]
362   // _GLIBCXX_RESOLVE_LIB_DEFECTS
363   // DR 740 - omit specialization for array objects with a compile time length
364   template<typename _Tp, typename _Dp>
365     class unique_ptr<_Tp[], _Dp>
366     {
367       // use SFINAE to determine whether _Del::pointer exists
368       class _Pointer
369       {
370 	template<typename _Up>
371 	  static typename _Up::pointer __test(typename _Up::pointer*);
372 
373 	template<typename _Up>
374 	  static _Tp* __test(...);
375 
376 	typedef typename remove_reference<_Dp>::type _Del;
377 
378       public:
379 	typedef decltype(__test<_Del>(0)) type;
380       };
381 
382       typedef std::tuple<typename _Pointer::type, _Dp>  __tuple_type;
383       __tuple_type                                      _M_t;
384 
385       template<typename _Up>
386 	using __remove_cv = typename remove_cv<_Up>::type;
387 
388       // like is_base_of<_Tp, _Up> but false if unqualified types are the same
389       template<typename _Up>
390 	using __is_derived_Tp
391 	  = __and_< is_base_of<_Tp, _Up>,
392 		    __not_<is_same<__remove_cv<_Tp>, __remove_cv<_Up>>> >;
393 
394       template<typename _Up, typename _Ep,
395 	       typename _Tp_pointer = typename _Pointer::type,
396 	       typename _Up_pointer = typename unique_ptr<_Up, _Ep>::pointer>
397 	using __safe_conversion = __and_<
398 	    is_convertible<_Up_pointer, _Tp_pointer>,
399 	    is_array<_Up>,
400 	    __or_<__not_<is_pointer<_Up_pointer>>,
401 		  __not_<is_pointer<_Tp_pointer>>,
402 		  __not_<__is_derived_Tp<typename remove_extent<_Up>::type>>
403 	    >
404 	  >;
405 
406     public:
407       typedef typename _Pointer::type	pointer;
408       typedef _Tp		 	element_type;
409       typedef _Dp                       deleter_type;
410 
411       // Constructors.
412 
413       /// Default constructor, creates a unique_ptr that owns nothing.
414       constexpr unique_ptr() noexcept
415       : _M_t()
416       { static_assert(!std::is_pointer<deleter_type>::value,
417 		      "constructed with null function pointer deleter"); }
418 
419       /** Takes ownership of a pointer.
420        *
421        * @param __p  A pointer to an array of @c element_type
422        *
423        * The deleter will be value-initialized.
424        */
425       explicit
426       unique_ptr(pointer __p) noexcept
427       : _M_t(__p, deleter_type())
428       { static_assert(!is_pointer<deleter_type>::value,
429 		      "constructed with null function pointer deleter"); }
430 
431       // Disable construction from convertible pointer types.
432       template<typename _Up, typename = _Require<is_pointer<pointer>,
433 	       is_convertible<_Up*, pointer>, __is_derived_Tp<_Up>>>
434 	explicit
435 	unique_ptr(_Up* __p) = delete;
436 
437       /** Takes ownership of a pointer.
438        *
439        * @param __p  A pointer to an array of @c element_type
440        * @param __d  A reference to a deleter.
441        *
442        * The deleter will be initialized with @p __d
443        */
444       unique_ptr(pointer __p,
445 	  typename conditional<is_reference<deleter_type>::value,
446 	      deleter_type, const deleter_type&>::type __d) noexcept
447       : _M_t(__p, __d) { }
448 
449       /** Takes ownership of a pointer.
450        *
451        * @param __p  A pointer to an array of @c element_type
452        * @param __d  A reference to a deleter.
453        *
454        * The deleter will be initialized with @p std::move(__d)
455        */
456       unique_ptr(pointer __p, typename
457 		 remove_reference<deleter_type>::type&& __d) noexcept
458       : _M_t(std::move(__p), std::move(__d))
459       { static_assert(!is_reference<deleter_type>::value,
460 		      "rvalue deleter bound to reference"); }
461 
462       /// Move constructor.
463       unique_ptr(unique_ptr&& __u) noexcept
464       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
465 
466       /// Creates a unique_ptr that owns nothing.
467       constexpr unique_ptr(nullptr_t) noexcept : unique_ptr() { }
468 
469       template<typename _Up, typename _Ep,
470 	       typename = _Require<__safe_conversion<_Up, _Ep>,
471 		 typename conditional<is_reference<_Dp>::value,
472 				      is_same<_Ep, _Dp>,
473 				      is_convertible<_Ep, _Dp>>::type
474 	       >>
475 	unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
476 	: _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
477 	{ }
478 
479       /// Destructor, invokes the deleter if the stored pointer is not null.
480       ~unique_ptr()
481       {
482 	auto& __ptr = std::get<0>(_M_t);
483 	if (__ptr != nullptr)
484 	  get_deleter()(__ptr);
485 	__ptr = pointer();
486       }
487 
488       // Assignment.
489 
490       /** @brief Move assignment operator.
491        *
492        * @param __u  The object to transfer ownership from.
493        *
494        * Invokes the deleter first if this object owns a pointer.
495        */
496       unique_ptr&
497       operator=(unique_ptr&& __u) noexcept
498       {
499 	reset(__u.release());
500 	get_deleter() = std::forward<deleter_type>(__u.get_deleter());
501 	return *this;
502       }
503 
504       /** @brief Assignment from another type.
505        *
506        * @param __u  The object to transfer ownership from, which owns a
507        *             convertible pointer to an array object.
508        *
509        * Invokes the deleter first if this object owns a pointer.
510        */
511       template<typename _Up, typename _Ep>
512 	typename
513 	enable_if<__safe_conversion<_Up, _Ep>::value, unique_ptr&>::type
514 	operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
515 	{
516 	  reset(__u.release());
517 	  get_deleter() = std::forward<_Ep>(__u.get_deleter());
518 	  return *this;
519 	}
520 
521       /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
522       unique_ptr&
523       operator=(nullptr_t) noexcept
524       {
525 	reset();
526 	return *this;
527       }
528 
529       // Observers.
530 
531       /// Access an element of owned array.
532       typename std::add_lvalue_reference<element_type>::type
533       operator[](size_t __i) const
534       {
535 	_GLIBCXX_DEBUG_ASSERT(get() != pointer());
536 	return get()[__i];
537       }
538 
539       /// Return the stored pointer.
540       pointer
541       get() const noexcept
542       { return std::get<0>(_M_t); }
543 
544       /// Return a reference to the stored deleter.
545       deleter_type&
546       get_deleter() noexcept
547       { return std::get<1>(_M_t); }
548 
549       /// Return a reference to the stored deleter.
550       const deleter_type&
551       get_deleter() const noexcept
552       { return std::get<1>(_M_t); }
553 
554       /// Return @c true if the stored pointer is not null.
555       explicit operator bool() const noexcept
556       { return get() == pointer() ? false : true; }
557 
558       // Modifiers.
559 
560       /// Release ownership of any stored pointer.
561       pointer
562       release() noexcept
563       {
564 	pointer __p = get();
565 	std::get<0>(_M_t) = pointer();
566 	return __p;
567       }
568 
569       /** @brief Replace the stored pointer.
570        *
571        * @param __p  The new pointer to store.
572        *
573        * The deleter will be invoked if a pointer is already owned.
574        */
575       void
576       reset(pointer __p = pointer()) noexcept
577       {
578 	using std::swap;
579 	swap(std::get<0>(_M_t), __p);
580 	if (__p != nullptr)
581 	  get_deleter()(__p);
582       }
583 
584       // Disable resetting from convertible pointer types.
585       template<typename _Up, typename = _Require<is_pointer<pointer>,
586 	       is_convertible<_Up*, pointer>, __is_derived_Tp<_Up>>>
587 	void reset(_Up*) = delete;
588 
589       /// Exchange the pointer and deleter with another object.
590       void
591       swap(unique_ptr& __u) noexcept
592       {
593 	using std::swap;
594 	swap(_M_t, __u._M_t);
595       }
596 
597       // Disable copy from lvalue.
598       unique_ptr(const unique_ptr&) = delete;
599       unique_ptr& operator=(const unique_ptr&) = delete;
600 
601       // Disable construction from convertible pointer types.
602       template<typename _Up, typename = _Require<is_pointer<pointer>,
603 	       is_convertible<_Up*, pointer>, __is_derived_Tp<_Up>>>
604 	unique_ptr(_Up*, typename
605 		   conditional<is_reference<deleter_type>::value,
606 		   deleter_type, const deleter_type&>::type) = delete;
607 
608       // Disable construction from convertible pointer types.
609       template<typename _Up, typename = _Require<is_pointer<pointer>,
610 	       is_convertible<_Up*, pointer>, __is_derived_Tp<_Up>>>
611 	unique_ptr(_Up*, typename
612 		   remove_reference<deleter_type>::type&&) = delete;
613     };
614 
615   template<typename _Tp, typename _Dp>
616     inline void
617     swap(unique_ptr<_Tp, _Dp>& __x,
618 	 unique_ptr<_Tp, _Dp>& __y) noexcept
619     { __x.swap(__y); }
620 
621   template<typename _Tp, typename _Dp,
622 	   typename _Up, typename _Ep>
623     inline bool
624     operator==(const unique_ptr<_Tp, _Dp>& __x,
625 	       const unique_ptr<_Up, _Ep>& __y)
626     { return __x.get() == __y.get(); }
627 
628   template<typename _Tp, typename _Dp>
629     inline bool
630     operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
631     { return !__x; }
632 
633   template<typename _Tp, typename _Dp>
634     inline bool
635     operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
636     { return !__x; }
637 
638   template<typename _Tp, typename _Dp,
639 	   typename _Up, typename _Ep>
640     inline bool
641     operator!=(const unique_ptr<_Tp, _Dp>& __x,
642 	       const unique_ptr<_Up, _Ep>& __y)
643     { return __x.get() != __y.get(); }
644 
645   template<typename _Tp, typename _Dp>
646     inline bool
647     operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
648     { return (bool)__x; }
649 
650   template<typename _Tp, typename _Dp>
651     inline bool
652     operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
653     { return (bool)__x; }
654 
655   template<typename _Tp, typename _Dp,
656 	   typename _Up, typename _Ep>
657     inline bool
658     operator<(const unique_ptr<_Tp, _Dp>& __x,
659 	      const unique_ptr<_Up, _Ep>& __y)
660     {
661       typedef typename
662 	std::common_type<typename unique_ptr<_Tp, _Dp>::pointer,
663 	                 typename unique_ptr<_Up, _Ep>::pointer>::type _CT;
664       return std::less<_CT>()(__x.get(), __y.get());
665     }
666 
667   template<typename _Tp, typename _Dp>
668     inline bool
669     operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
670     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
671 								 nullptr); }
672 
673   template<typename _Tp, typename _Dp>
674     inline bool
675     operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
676     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
677 								 __x.get()); }
678 
679   template<typename _Tp, typename _Dp,
680 	   typename _Up, typename _Ep>
681     inline bool
682     operator<=(const unique_ptr<_Tp, _Dp>& __x,
683 	       const unique_ptr<_Up, _Ep>& __y)
684     { return !(__y < __x); }
685 
686   template<typename _Tp, typename _Dp>
687     inline bool
688     operator<=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
689     { return !(nullptr < __x); }
690 
691   template<typename _Tp, typename _Dp>
692     inline bool
693     operator<=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
694     { return !(__x < nullptr); }
695 
696   template<typename _Tp, typename _Dp,
697 	   typename _Up, typename _Ep>
698     inline bool
699     operator>(const unique_ptr<_Tp, _Dp>& __x,
700 	      const unique_ptr<_Up, _Ep>& __y)
701     { return (__y < __x); }
702 
703   template<typename _Tp, typename _Dp>
704     inline bool
705     operator>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
706     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
707 								 __x.get()); }
708 
709   template<typename _Tp, typename _Dp>
710     inline bool
711     operator>(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
712     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
713 								 nullptr); }
714 
715   template<typename _Tp, typename _Dp,
716 	   typename _Up, typename _Ep>
717     inline bool
718     operator>=(const unique_ptr<_Tp, _Dp>& __x,
719 	       const unique_ptr<_Up, _Ep>& __y)
720     { return !(__x < __y); }
721 
722   template<typename _Tp, typename _Dp>
723     inline bool
724     operator>=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
725     { return !(__x < nullptr); }
726 
727   template<typename _Tp, typename _Dp>
728     inline bool
729     operator>=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
730     { return !(nullptr < __x); }
731 
732   /// std::hash specialization for unique_ptr.
733   template<typename _Tp, typename _Dp>
734     struct hash<unique_ptr<_Tp, _Dp>>
735     : public __hash_base<size_t, unique_ptr<_Tp, _Dp>>
736     {
737       size_t
738       operator()(const unique_ptr<_Tp, _Dp>& __u) const noexcept
739       {
740 	typedef unique_ptr<_Tp, _Dp> _UP;
741 	return std::hash<typename _UP::pointer>()(__u.get());
742       }
743     };
744 
745 #if __cplusplus > 201103L
746 
747 #define __cpp_lib_make_unique 201304
748 
749   template<typename _Tp>
750     struct _MakeUniq
751     { typedef unique_ptr<_Tp> __single_object; };
752 
753   template<typename _Tp>
754     struct _MakeUniq<_Tp[]>
755     { typedef unique_ptr<_Tp[]> __array; };
756 
757   template<typename _Tp, size_t _Bound>
758     struct _MakeUniq<_Tp[_Bound]>
759     { struct __invalid_type { }; };
760 
761   /// std::make_unique for single objects
762   template<typename _Tp, typename... _Args>
763     inline typename _MakeUniq<_Tp>::__single_object
764     make_unique(_Args&&... __args)
765     { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
766 
767   /// std::make_unique for arrays of unknown bound
768   template<typename _Tp>
769     inline typename _MakeUniq<_Tp>::__array
770     make_unique(size_t __num)
771     { return unique_ptr<_Tp>(new typename remove_extent<_Tp>::type[__num]()); }
772 
773   /// Disable std::make_unique for arrays of known bound
774   template<typename _Tp, typename... _Args>
775     inline typename _MakeUniq<_Tp>::__invalid_type
776     make_unique(_Args&&...) = delete;
777 #endif
778 
779   // @} group pointer_abstractions
780 
781 _GLIBCXX_END_NAMESPACE_VERSION
782 } // namespace
783 
784 #endif /* _UNIQUE_PTR_H */
785