libstdc++-v3/include/bits/unique_ptr.h

   1 // unique_ptr implementation -*- C++ -*-
   2
   3 // Copyright (C) 2008-2016 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/assertions.h>
  35 #include <type_traits>
  36 #include <utility>
  37 #include <tuple>
  38 #include <bits/stl_function.h>
  39
  40 namespace std _GLIBCXX_VISIBILITY(default)
  41 {
  42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  43
  44   /**
  45    * @addtogroup pointer_abstractions
  46    * @{
  47    */
  48
  49 #if _GLIBCXX_USE_DEPRECATED
  50   template<typename> class auto_ptr;
  51 #endif
  52
  53   /// Primary template of default_delete, used by unique_ptr
  54   template<typename _Tp>
  55     struct default_delete
  56     {
  57       /// Default constructor
  58       constexpr default_delete() noexcept = default;
  59
  60       /** @brief Converting constructor.
  61        *
  62        * Allows conversion from a deleter for arrays of another type, @p _Up,
  63        * only if @p _Up* is convertible to @p _Tp*.
  64        */
  65       template<typename _Up, typename = typename
  66                enable_if<is_convertible<_Up*, _Tp*>::value>::type>
  67         default_delete(const default_delete<_Up>&) noexcept { }
  68
  69       /// Calls @c delete @p __ptr
  70       void
  71       operator()(_Tp* __ptr) const
  72       {
  73         static_assert(!is_void<_Tp>::value,
  74                       "can't delete pointer to incomplete type");
  75         static_assert(sizeof(_Tp)>0,
  76                       "can't delete pointer to incomplete type");
  77         delete __ptr;
  78       }
  79     };
  80
  81   // _GLIBCXX_RESOLVE_LIB_DEFECTS
  82   // DR 740 - omit specialization for array objects with a compile time length
  83   /// Specialization for arrays, default_delete.
  84   template<typename _Tp>
  85     struct default_delete<_Tp[]>
  86     {
  87     public:
  88       /// Default constructor
  89       constexpr default_delete() noexcept = default;
  90
  91       /** @brief Converting constructor.
  92        *
  93        * Allows conversion from a deleter for arrays of another type, such as
  94        * a const-qualified version of @p _Tp.
  95        *
  96        * Conversions from types derived from @c _Tp are not allowed because
  97        * it is unsafe to @c delete[] an array of derived types through a
  98        * pointer to the base type.
  99        */
 100       template<typename _Up, typename = typename
 101                enable_if<is_convertible<_Up(*)[], _Tp(*)[]>::value>::type>
 102         default_delete(const default_delete<_Up[]>&) noexcept { }
 103
 104       /// Calls @c delete[] @p __ptr
 105       template<typename _Up>
 106       typename enable_if<is_convertible<_Up(*)[], _Tp(*)[]>::value>::type
 107         operator()(_Up* __ptr) const
 108       {
 109         static_assert(sizeof(_Tp)>0,
 110                       "can't delete pointer to incomplete type");
 111         delete [] __ptr;
 112       }
 113     };
 114
 115   template <typename _Tp, typename _Dp>
 116     class __uniq_ptr_impl
 117     {
 118       template <typename _Up, typename _Ep, typename = void>
 119         struct _Ptr
 120         {
 121           using type = _Up*;
 122         };
 123
 124       template <typename _Up, typename _Ep>
 125         struct
 126         _Ptr<_Up, _Ep, __void_t<typename remove_reference<_Ep>::type::pointer>>
 127         {
 128           using type = typename remove_reference<_Ep>::type::pointer;
 129         };
 130
 131     public:
 132       using pointer = typename _Ptr<_Tp, _Dp>::type;
 133
 134       __uniq_ptr_impl() = default;
 135       __uniq_ptr_impl(pointer __p) : _M_t() { _M_ptr() = __p; }
 136
 137       template<typename _Del>
 138       __uniq_ptr_impl(pointer __p, _Del&& __d)
 139         : _M_t(__p, std::forward<_Del>(__d)) { }
 140
 141       pointer&   _M_ptr() { return std::get<0>(_M_t); }
 142       pointer    _M_ptr() const { return std::get<0>(_M_t); }
 143       _Dp&       _M_deleter() { return std::get<1>(_M_t); }
 144       const _Dp& _M_deleter() const { return std::get<1>(_M_t); }
 145
 146     private:
 147       tuple<pointer, _Dp> _M_t;
 148     };
 149
 150   /// 20.7.1.2 unique_ptr for single objects.
 151   template <typename _Tp, typename _Dp = default_delete<_Tp>>
 152     class unique_ptr
 153     {
 154       __uniq_ptr_impl<_Tp, _Dp> _M_t;
 155
 156     public:
 157       using pointer       = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
 158       using element_type  = _Tp;
 159       using deleter_type  = _Dp;
 160
 161       // helper template for detecting a safe conversion from another
 162       // unique_ptr
 163       template<typename _Up, typename _Ep>
 164         using __safe_conversion_up = __and_<
 165                 is_convertible<typename unique_ptr<_Up, _Ep>::pointer, pointer>,
 166                 __not_<is_array<_Up>>,
 167                 __or_<__and_<is_reference<deleter_type>,
 168                              is_same<deleter_type, _Ep>>,
 169                       __and_<__not_<is_reference<deleter_type>>,
 170                              is_convertible<_Ep, deleter_type>>
 171                 >
 172               >;
 173
 174       // Constructors.
 175
 176       /// Default constructor, creates a unique_ptr that owns nothing.
 177       constexpr unique_ptr() noexcept
 178       : _M_t()
 179       { static_assert(!is_pointer<deleter_type>::value,
 180                      "constructed with null function pointer deleter"); }
 181
 182       /** Takes ownership of a pointer.
 183        *
 184        * @param __p  A pointer to an object of @c element_type
 185        *
 186        * The deleter will be value-initialized.
 187        */
 188       explicit
 189       unique_ptr(pointer __p) noexcept
 190       : _M_t(__p)
 191       { static_assert(!is_pointer<deleter_type>::value,
 192                      "constructed with null function pointer deleter"); }
 193
 194       /** Takes ownership of a pointer.
 195        *
 196        * @param __p  A pointer to an object of @c element_type
 197        * @param __d  A reference to a deleter.
 198        *
 199        * The deleter will be initialized with @p __d
 200        */
 201       unique_ptr(pointer __p,
 202           typename conditional<is_reference<deleter_type>::value,
 203             deleter_type, const deleter_type&>::type __d) noexcept
 204       : _M_t(__p, __d) { }
 205
 206       /** Takes ownership of a pointer.
 207        *
 208        * @param __p  A pointer to an object of @c element_type
 209        * @param __d  An rvalue reference to a deleter.
 210        *
 211        * The deleter will be initialized with @p std::move(__d)
 212        */
 213       unique_ptr(pointer __p,
 214           typename remove_reference<deleter_type>::type&& __d) noexcept
 215       : _M_t(std::move(__p), std::move(__d))
 216       { static_assert(!std::is_reference<deleter_type>::value,
 217                       "rvalue deleter bound to reference"); }
 218
 219       /// Creates a unique_ptr that owns nothing.
 220       constexpr unique_ptr(nullptr_t) noexcept : unique_ptr() { }
 221
 222       // Move constructors.
 223
 224       /// Move constructor.
 225       unique_ptr(unique_ptr&& __u) noexcept
 226       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 227
 228       /** @brief Converting constructor from another type
 229        *
 230        * Requires that the pointer owned by @p __u is convertible to the
 231        * type of pointer owned by this object, @p __u does not own an array,
 232        * and @p __u has a compatible deleter type.
 233        */
 234       template<typename _Up, typename _Ep, typename = _Require<
 235                __safe_conversion_up<_Up, _Ep>,
 236                typename conditional<is_reference<_Dp>::value,
 237                                     is_same<_Ep, _Dp>,
 238                                     is_convertible<_Ep, _Dp>>::type>>
 239         unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
 240         : _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
 241         { }
 242
 243 #if _GLIBCXX_USE_DEPRECATED
 244       /// Converting constructor from @c auto_ptr
 245       template<typename _Up, typename = _Require<
 246                is_convertible<_Up*, _Tp*>, is_same<_Dp, default_delete<_Tp>>>>
 247         unique_ptr(auto_ptr<_Up>&& __u) noexcept;
 248 #endif
 249
 250       /// Destructor, invokes the deleter if the stored pointer is not null.
 251       ~unique_ptr() noexcept
 252       {
 253         auto& __ptr = _M_t._M_ptr();
 254         if (__ptr != nullptr)
 255           get_deleter()(__ptr);
 256         __ptr = pointer();
 257       }
 258
 259       // Assignment.
 260
 261       /** @brief Move assignment operator.
 262        *
 263        * @param __u  The object to transfer ownership from.
 264        *
 265        * Invokes the deleter first if this object owns a pointer.
 266        */
 267       unique_ptr&
 268       operator=(unique_ptr&& __u) noexcept
 269       {
 270         reset(__u.release());
 271         get_deleter() = std::forward<deleter_type>(__u.get_deleter());
 272         return *this;
 273       }
 274
 275       /** @brief Assignment from another type.
 276        *
 277        * @param __u  The object to transfer ownership from, which owns a
 278        *             convertible pointer to a non-array object.
 279        *
 280        * Invokes the deleter first if this object owns a pointer.
 281        */
 282       template<typename _Up, typename _Ep>
 283         typename enable_if< __and_<
 284           __safe_conversion_up<_Up, _Ep>,
 285           is_assignable<deleter_type&, _Ep&&>
 286           >::value,
 287           unique_ptr&>::type
 288         operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
 289         {
 290           reset(__u.release());
 291           get_deleter() = std::forward<_Ep>(__u.get_deleter());
 292           return *this;
 293         }
 294
 295       /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
 296       unique_ptr&
 297       operator=(nullptr_t) noexcept
 298       {
 299         reset();
 300         return *this;
 301       }
 302
 303       // Observers.
 304
 305       /// Dereference the stored pointer.
 306       typename add_lvalue_reference<element_type>::type
 307       operator*() const
 308       {
 309         __glibcxx_assert(get() != pointer());
 310         return *get();
 311       }
 312
 313       /// Return the stored pointer.
 314       pointer
 315       operator->() const noexcept
 316       {
 317         _GLIBCXX_DEBUG_PEDASSERT(get() != pointer());
 318         return get();
 319       }
 320
 321       /// Return the stored pointer.
 322       pointer
 323       get() const noexcept
 324       { return _M_t._M_ptr(); }
 325
 326       /// Return a reference to the stored deleter.
 327       deleter_type&
 328       get_deleter() noexcept
 329       { return _M_t._M_deleter(); }
 330
 331       /// Return a reference to the stored deleter.
 332       const deleter_type&
 333       get_deleter() const noexcept
 334       { return _M_t._M_deleter(); }
 335
 336       /// Return @c true if the stored pointer is not null.
 337       explicit operator bool() const noexcept
 338       { return get() == pointer() ? false : true; }
 339
 340       // Modifiers.
 341
 342       /// Release ownership of any stored pointer.
 343       pointer
 344       release() noexcept
 345       {
 346         pointer __p = get();
 347         _M_t._M_ptr() = pointer();
 348         return __p;
 349       }
 350
 351       /** @brief Replace the stored pointer.
 352        *
 353        * @param __p  The new pointer to store.
 354        *
 355        * The deleter will be invoked if a pointer is already owned.
 356        */
 357       void
 358       reset(pointer __p = pointer()) noexcept
 359       {
 360         using std::swap;
 361         swap(_M_t._M_ptr(), __p);
 362         if (__p != pointer())
 363           get_deleter()(__p);
 364       }
 365
 366       /// Exchange the pointer and deleter with another object.
 367       void
 368       swap(unique_ptr& __u) noexcept
 369       {
 370         using std::swap;
 371         swap(_M_t, __u._M_t);
 372       }
 373
 374       // Disable copy from lvalue.
 375       unique_ptr(const unique_ptr&) = delete;
 376       unique_ptr& operator=(const unique_ptr&) = delete;
 377   };
 378
 379   /// 20.7.1.3 unique_ptr for array objects with a runtime length
 380   // [unique.ptr.runtime]
 381   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 382   // DR 740 - omit specialization for array objects with a compile time length
 383   template<typename _Tp, typename _Dp>
 384     class unique_ptr<_Tp[], _Dp>
 385     {
 386       __uniq_ptr_impl<_Tp, _Dp> _M_t;
 387
 388       template<typename _Up>
 389         using __remove_cv = typename remove_cv<_Up>::type;
 390
 391       // like is_base_of<_Tp, _Up> but false if unqualified types are the same
 392       template<typename _Up>
 393         using __is_derived_Tp
 394           = __and_< is_base_of<_Tp, _Up>,
 395                     __not_<is_same<__remove_cv<_Tp>, __remove_cv<_Up>>> >;
 396
 397     public:
 398       using pointer       = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
 399       using element_type  = _Tp;
 400       using deleter_type  = _Dp;
 401
 402       // helper template for detecting a safe conversion from another
 403       // unique_ptr
 404       template<typename _Up, typename _Ep,
 405                typename _Up_up = unique_ptr<_Up, _Ep>,
 406                typename _Up_element_type = typename _Up_up::element_type>
 407         using __safe_conversion_up = __and_<
 408           is_array<_Up>,
 409           is_same<pointer, element_type*>,
 410           is_same<typename _Up_up::pointer, _Up_element_type*>,
 411           is_convertible<_Up_element_type(*)[], element_type(*)[]>,
 412           __or_<__and_<is_reference<deleter_type>, is_same<deleter_type, _Ep>>,
 413                 __and_<__not_<is_reference<deleter_type>>,
 414                        is_convertible<_Ep, deleter_type>>>
 415         >;
 416
 417       // helper template for detecting a safe conversion from a raw pointer
 418       template<typename _Up>
 419         using __safe_conversion_raw = __and_<
 420           __or_<__or_<is_same<_Up, pointer>,
 421                       is_same<_Up, nullptr_t>>,
 422                 __and_<is_pointer<_Up>,
 423                        is_same<pointer, element_type*>,
 424                        is_convertible<
 425                          typename remove_pointer<_Up>::type(*)[],
 426                          element_type(*)[]>
 427                 >
 428           >
 429         >;
 430
 431       // Constructors.
 432
 433       /// Default constructor, creates a unique_ptr that owns nothing.
 434       constexpr unique_ptr() noexcept
 435       : _M_t()
 436       { static_assert(!std::is_pointer<deleter_type>::value,
 437                       "constructed with null function pointer deleter"); }
 438
 439       /** Takes ownership of a pointer.
 440        *
 441        * @param __p  A pointer to an array of a type safely convertible
 442        * to an array of @c element_type
 443        *
 444        * The deleter will be value-initialized.
 445        */
 446       template<typename _Up,
 447                typename = typename enable_if<
 448                  __safe_conversion_raw<_Up>::value, bool>::type>
 449       explicit
 450       unique_ptr(_Up __p) noexcept
 451       : _M_t(__p)
 452       { static_assert(!is_pointer<deleter_type>::value,
 453                       "constructed with null function pointer deleter"); }
 454
 455       /** Takes ownership of a pointer.
 456        *
 457        * @param __p  A pointer to an array of a type safely convertible
 458        * to an array of @c element_type
 459        * @param __d  A reference to a deleter.
 460        *
 461        * The deleter will be initialized with @p __d
 462        */
 463       template<typename _Up,
 464                typename = typename enable_if<
 465                  __safe_conversion_raw<_Up>::value, bool>::type>
 466       unique_ptr(_Up __p,
 467                  typename conditional<is_reference<deleter_type>::value,
 468                  deleter_type, const deleter_type&>::type __d) noexcept
 469       : _M_t(__p, __d) { }
 470
 471       /** Takes ownership of a pointer.
 472        *
 473        * @param __p  A pointer to an array of a type safely convertible
 474        * to an array of @c element_type
 475        * @param __d  A reference to a deleter.
 476        *
 477        * The deleter will be initialized with @p std::move(__d)
 478        */
 479       template<typename _Up,
 480                typename = typename enable_if<
 481                  __safe_conversion_raw<_Up>::value, bool>::type>
 482       unique_ptr(_Up __p, typename
 483                  remove_reference<deleter_type>::type&& __d) noexcept
 484       : _M_t(std::move(__p), std::move(__d))
 485       { static_assert(!is_reference<deleter_type>::value,
 486                       "rvalue deleter bound to reference"); }
 487
 488       /// Move constructor.
 489       unique_ptr(unique_ptr&& __u) noexcept
 490       : _M_t(__u.release(), std::forward<deleter_type>(__u.get_deleter())) { }
 491
 492       /// Creates a unique_ptr that owns nothing.
 493       constexpr unique_ptr(nullptr_t) noexcept : unique_ptr() { }
 494
 495       template<typename _Up, typename _Ep,
 496                typename = _Require<__safe_conversion_up<_Up, _Ep>>>
 497         unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
 498         : _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
 499         { }
 500
 501       /// Destructor, invokes the deleter if the stored pointer is not null.
 502       ~unique_ptr()
 503       {
 504         auto& __ptr = _M_t._M_ptr();
 505         if (__ptr != nullptr)
 506           get_deleter()(__ptr);
 507         __ptr = pointer();
 508       }
 509
 510       // Assignment.
 511
 512       /** @brief Move assignment operator.
 513        *
 514        * @param __u  The object to transfer ownership from.
 515        *
 516        * Invokes the deleter first if this object owns a pointer.
 517        */
 518       unique_ptr&
 519       operator=(unique_ptr&& __u) noexcept
 520       {
 521         reset(__u.release());
 522         get_deleter() = std::forward<deleter_type>(__u.get_deleter());
 523         return *this;
 524       }
 525
 526       /** @brief Assignment from another type.
 527        *
 528        * @param __u  The object to transfer ownership from, which owns a
 529        *             convertible pointer to an array object.
 530        *
 531        * Invokes the deleter first if this object owns a pointer.
 532        */
 533       template<typename _Up, typename _Ep>
 534         typename
 535         enable_if<__and_<__safe_conversion_up<_Up, _Ep>,
 536                          is_assignable<deleter_type&, _Ep&&>
 537                   >::value,
 538                   unique_ptr&>::type
 539         operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
 540         {
 541           reset(__u.release());
 542           get_deleter() = std::forward<_Ep>(__u.get_deleter());
 543           return *this;
 544         }
 545
 546       /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
 547       unique_ptr&
 548       operator=(nullptr_t) noexcept
 549       {
 550         reset();
 551         return *this;
 552       }
 553
 554       // Observers.
 555
 556       /// Access an element of owned array.
 557       typename std::add_lvalue_reference<element_type>::type
 558       operator[](size_t __i) const
 559       {
 560         __glibcxx_assert(get() != pointer());
 561         return get()[__i];
 562       }
 563
 564       /// Return the stored pointer.
 565       pointer
 566       get() const noexcept
 567       { return _M_t._M_ptr(); }
 568
 569       /// Return a reference to the stored deleter.
 570       deleter_type&
 571       get_deleter() noexcept
 572       { return _M_t._M_deleter(); }
 573
 574       /// Return a reference to the stored deleter.
 575       const deleter_type&
 576       get_deleter() const noexcept
 577       { return _M_t._M_deleter(); }
 578
 579       /// Return @c true if the stored pointer is not null.
 580       explicit operator bool() const noexcept
 581       { return get() == pointer() ? false : true; }
 582
 583       // Modifiers.
 584
 585       /// Release ownership of any stored pointer.
 586       pointer
 587       release() noexcept
 588       {
 589         pointer __p = get();
 590         _M_t._M_ptr() = pointer();
 591         return __p;
 592       }
 593
 594       /** @brief Replace the stored pointer.
 595        *
 596        * @param __p  The new pointer to store.
 597        *
 598        * The deleter will be invoked if a pointer is already owned.
 599        */
 600       template <typename _Up,
 601                 typename = _Require<
 602                   __or_<is_same<_Up, pointer>,
 603                         __and_<is_same<pointer, element_type*>,
 604                                is_pointer<_Up>,
 605                                is_convertible<
 606                                  typename remove_pointer<_Up>::type(*)[],
 607                                  element_type(*)[]
 608                                >
 609                         >
 610                   >
 611                >>
 612       void
 613       reset(_Up __p) noexcept
 614       {
 615         pointer __ptr = __p;
 616         using std::swap;
 617         swap(_M_t._M_ptr(), __ptr);
 618         if (__ptr != nullptr)
 619           get_deleter()(__ptr);
 620       }
 621
 622       void reset(nullptr_t = nullptr) noexcept
 623       {
 624         reset(pointer());
 625       }
 626
 627       /// Exchange the pointer and deleter with another object.
 628       void
 629       swap(unique_ptr& __u) noexcept
 630       {
 631         using std::swap;
 632         swap(_M_t, __u._M_t);
 633       }
 634
 635       // Disable copy from lvalue.
 636       unique_ptr(const unique_ptr&) = delete;
 637       unique_ptr& operator=(const unique_ptr&) = delete;
 638     };
 639
 640   template<typename _Tp, typename _Dp>
 641     inline
 642 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
 643     // Constrained free swap overload, see p0185r1
 644     typename enable_if<__is_swappable<_Dp>::value>::type
 645 #else
 646     void
 647 #endif
 648     swap(unique_ptr<_Tp, _Dp>& __x,
 649          unique_ptr<_Tp, _Dp>& __y) noexcept
 650     { __x.swap(__y); }
 651
 652   template<typename _Tp, typename _Dp,
 653            typename _Up, typename _Ep>
 654     inline bool
 655     operator==(const unique_ptr<_Tp, _Dp>& __x,
 656                const unique_ptr<_Up, _Ep>& __y)
 657     { return __x.get() == __y.get(); }
 658
 659   template<typename _Tp, typename _Dp>
 660     inline bool
 661     operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
 662     { return !__x; }
 663
 664   template<typename _Tp, typename _Dp>
 665     inline bool
 666     operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
 667     { return !__x; }
 668
 669   template<typename _Tp, typename _Dp,
 670            typename _Up, typename _Ep>
 671     inline bool
 672     operator!=(const unique_ptr<_Tp, _Dp>& __x,
 673                const unique_ptr<_Up, _Ep>& __y)
 674     { return __x.get() != __y.get(); }
 675
 676   template<typename _Tp, typename _Dp>
 677     inline bool
 678     operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
 679     { return (bool)__x; }
 680
 681   template<typename _Tp, typename _Dp>
 682     inline bool
 683     operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
 684     { return (bool)__x; }
 685
 686   template<typename _Tp, typename _Dp,
 687            typename _Up, typename _Ep>
 688     inline bool
 689     operator<(const unique_ptr<_Tp, _Dp>& __x,
 690               const unique_ptr<_Up, _Ep>& __y)
 691     {
 692       typedef typename
 693         std::common_type<typename unique_ptr<_Tp, _Dp>::pointer,
 694                          typename unique_ptr<_Up, _Ep>::pointer>::type _CT;
 695       return std::less<_CT>()(__x.get(), __y.get());
 696     }
 697
 698   template<typename _Tp, typename _Dp>
 699     inline bool
 700     operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
 701     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
 702                                                                  nullptr); }
 703
 704   template<typename _Tp, typename _Dp>
 705     inline bool
 706     operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
 707     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
 708                                                                  __x.get()); }
 709
 710   template<typename _Tp, typename _Dp,
 711            typename _Up, typename _Ep>
 712     inline bool
 713     operator<=(const unique_ptr<_Tp, _Dp>& __x,
 714                const unique_ptr<_Up, _Ep>& __y)
 715     { return !(__y < __x); }
 716
 717   template<typename _Tp, typename _Dp>
 718     inline bool
 719     operator<=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
 720     { return !(nullptr < __x); }
 721
 722   template<typename _Tp, typename _Dp>
 723     inline bool
 724     operator<=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
 725     { return !(__x < nullptr); }
 726
 727   template<typename _Tp, typename _Dp,
 728            typename _Up, typename _Ep>
 729     inline bool
 730     operator>(const unique_ptr<_Tp, _Dp>& __x,
 731               const unique_ptr<_Up, _Ep>& __y)
 732     { return (__y < __x); }
 733
 734   template<typename _Tp, typename _Dp>
 735     inline bool
 736     operator>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
 737     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
 738                                                                  __x.get()); }
 739
 740   template<typename _Tp, typename _Dp>
 741     inline bool
 742     operator>(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
 743     { return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
 744                                                                  nullptr); }
 745
 746   template<typename _Tp, typename _Dp,
 747            typename _Up, typename _Ep>
 748     inline bool
 749     operator>=(const unique_ptr<_Tp, _Dp>& __x,
 750                const unique_ptr<_Up, _Ep>& __y)
 751     { return !(__x < __y); }
 752
 753   template<typename _Tp, typename _Dp>
 754     inline bool
 755     operator>=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
 756     { return !(__x < nullptr); }
 757
 758   template<typename _Tp, typename _Dp>
 759     inline bool
 760     operator>=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
 761     { return !(nullptr < __x); }
 762
 763   /// std::hash specialization for unique_ptr.
 764   template<typename _Tp, typename _Dp>
 765     struct hash<unique_ptr<_Tp, _Dp>>
 766     : public __hash_base<size_t, unique_ptr<_Tp, _Dp>>
 767     {
 768       size_t
 769       operator()(const unique_ptr<_Tp, _Dp>& __u) const noexcept
 770       {
 771         typedef unique_ptr<_Tp, _Dp> _UP;
 772         return std::hash<typename _UP::pointer>()(__u.get());
 773       }
 774     };
 775
 776 #if __cplusplus > 201103L
 777
 778 #define __cpp_lib_make_unique 201304
 779
 780   template<typename _Tp>
 781     struct _MakeUniq
 782     { typedef unique_ptr<_Tp> __single_object; };
 783
 784   template<typename _Tp>
 785     struct _MakeUniq<_Tp[]>
 786     { typedef unique_ptr<_Tp[]> __array; };
 787
 788   template<typename _Tp, size_t _Bound>
 789     struct _MakeUniq<_Tp[_Bound]>
 790     { struct __invalid_type { }; };
 791
 792   /// std::make_unique for single objects
 793   template<typename _Tp, typename... _Args>
 794     inline typename _MakeUniq<_Tp>::__single_object
 795     make_unique(_Args&&... __args)
 796     { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
 797
 798   /// std::make_unique for arrays of unknown bound
 799   template<typename _Tp>
 800     inline typename _MakeUniq<_Tp>::__array
 801     make_unique(size_t __num)
 802     { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]()); }
 803
 804   /// Disable std::make_unique for arrays of known bound
 805   template<typename _Tp, typename... _Args>
 806     inline typename _MakeUniq<_Tp>::__invalid_type
 807     make_unique(_Args&&...) = delete;
 808 #endif
 809
 810   // @} group pointer_abstractions
 811
 812 _GLIBCXX_END_NAMESPACE_VERSION
 813 } // namespace
 814
 815 #endif /* _UNIQUE_PTR_H */