libstdc++
memory
Go to the documentation of this file.
00001 // <experimental/memory> -*- C++ -*-
00002 
00003 // Copyright (C) 2015-2017 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /** @file experimental/memory
00026  *  This is a TS C++ Library header.
00027  */
00028 
00029 //
00030 // N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
00031 //
00032 
00033 #ifndef _GLIBCXX_EXPERIMENTAL_MEMORY
00034 #define _GLIBCXX_EXPERIMENTAL_MEMORY 1
00035 
00036 #pragma GCC system_header
00037 
00038 #if __cplusplus <= 201103L
00039 # include <bits/c++14_warning.h>
00040 #else
00041 
00042 #include <memory>
00043 #include <type_traits>
00044 #include <utility>
00045 #include <experimental/bits/shared_ptr.h>
00046 #include <bits/functional_hash.h>
00047 
00048 namespace std _GLIBCXX_VISIBILITY(default)
00049 {
00050 namespace experimental
00051 {
00052 inline namespace fundamentals_v2
00053 {
00054 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00055 
00056 #define __cpp_lib_experimental_observer_ptr 201411
00057 
00058   template <typename _Tp>
00059     class observer_ptr
00060     {
00061     public:
00062       // publish our template parameter and variations thereof
00063       using element_type = _Tp;
00064       using __pointer = add_pointer_t<_Tp>;            // exposition-only
00065       using __reference = add_lvalue_reference_t<_Tp>; // exposition-only
00066 
00067       // 3.2.2, observer_ptr constructors
00068       // default c’tor
00069       constexpr observer_ptr() noexcept
00070       : __t()
00071       { }
00072 
00073       // pointer-accepting c’tors
00074       constexpr observer_ptr(nullptr_t) noexcept
00075       : __t()
00076       { }
00077 
00078       constexpr explicit observer_ptr(__pointer __p) noexcept
00079       : __t(__p)
00080       { }
00081 
00082       // copying c’tors (in addition to compiler-generated copy c’tor)
00083       template <typename _Up,
00084                 typename = typename enable_if<
00085                   is_convertible<typename add_pointer<_Up>::type, __pointer
00086                   >::value
00087                 >::type>
00088       constexpr observer_ptr(observer_ptr<_Up> __p) noexcept
00089       : __t(__p.get())
00090       {
00091       }
00092 
00093       // 3.2.3, observer_ptr observers
00094       constexpr __pointer
00095       get() const noexcept
00096       {
00097         return __t;
00098       }
00099 
00100       constexpr __reference
00101       operator*() const
00102       {
00103         return *get();
00104       }
00105 
00106       constexpr __pointer
00107       operator->() const noexcept
00108       {
00109         return get();
00110       }
00111 
00112       constexpr explicit operator bool() const noexcept
00113       {
00114         return get() != nullptr;
00115       }
00116 
00117       // 3.2.4, observer_ptr conversions
00118       constexpr explicit operator __pointer() const noexcept
00119       {
00120         return get();
00121       }
00122 
00123       // 3.2.5, observer_ptr modifiers
00124       constexpr __pointer
00125       release() noexcept
00126       {
00127         __pointer __tmp = get();
00128         reset();
00129         return __tmp;
00130       }
00131 
00132       constexpr void
00133       reset(__pointer __p = nullptr) noexcept
00134       {
00135         __t = __p;
00136       }
00137 
00138       constexpr void
00139       swap(observer_ptr& __p) noexcept
00140       {
00141         std::swap(__t, __p.__t);
00142       }
00143 
00144     private:
00145       __pointer __t;
00146     }; // observer_ptr<>
00147 
00148   template<typename _Tp>
00149     void
00150     swap(observer_ptr<_Tp>& __p1, observer_ptr<_Tp>& __p2) noexcept
00151     {
00152       __p1.swap(__p2);
00153     }
00154 
00155   template<typename _Tp>
00156     observer_ptr<_Tp>
00157     make_observer(_Tp* __p) noexcept
00158     {
00159       return observer_ptr<_Tp>(__p);
00160     }
00161 
00162   template<typename _Tp, typename _Up>
00163     bool
00164     operator==(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
00165     {
00166       return __p1.get() == __p2.get();
00167     }
00168 
00169   template<typename _Tp, typename _Up>
00170     bool
00171     operator!=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
00172     {
00173     return !(__p1 == __p2);
00174     }
00175 
00176   template<typename _Tp>
00177     bool
00178     operator==(observer_ptr<_Tp> __p, nullptr_t) noexcept
00179     {
00180       return !__p;
00181     }
00182 
00183   template<typename _Tp>
00184     bool
00185     operator==(nullptr_t, observer_ptr<_Tp> __p) noexcept
00186     {
00187       return !__p;
00188     }
00189 
00190   template<typename _Tp>
00191     bool
00192     operator!=(observer_ptr<_Tp> __p, nullptr_t) noexcept
00193     {
00194       return bool(__p);
00195     }
00196 
00197   template<typename _Tp>
00198     bool
00199     operator!=(nullptr_t, observer_ptr<_Tp> __p) noexcept
00200     {
00201       return bool(__p);
00202     }
00203 
00204   template<typename _Tp, typename _Up>
00205     bool
00206     operator<(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
00207     {
00208       return std::less<typename common_type<typename add_pointer<_Tp>::type,
00209                                             typename add_pointer<_Up>::type
00210                                             >::type
00211                        >{}(__p1.get(), __p2.get());
00212     }
00213 
00214   template<typename _Tp, typename _Up>
00215     bool
00216     operator>(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
00217     {
00218       return __p2 < __p1;
00219     }
00220 
00221   template<typename _Tp, typename _Up>
00222     bool
00223     operator<=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
00224     {
00225       return !(__p2 < __p1);
00226     }
00227 
00228   template<typename _Tp, typename _Up>
00229     bool
00230     operator>=(observer_ptr<_Tp> __p1, observer_ptr<_Up> __p2)
00231     {
00232       return !(__p1 < __p2);
00233     }
00234 
00235 _GLIBCXX_END_NAMESPACE_VERSION
00236 } // namespace fundamentals_v2
00237 } // namespace experimental
00238 
00239 template <typename _Tp>
00240   struct hash<experimental::observer_ptr<_Tp>>
00241   {
00242     using result_type = size_t;
00243     using argument_type = experimental::observer_ptr<_Tp>;
00244 
00245     size_t
00246     operator()(const experimental::observer_ptr<_Tp>& __t) const
00247     noexcept(noexcept(hash<typename add_pointer<_Tp>::type> {}(__t.get())))
00248     {
00249       return hash<typename add_pointer<_Tp>::type> {}(__t.get());
00250     }
00251   };
00252 
00253 } // namespace std
00254 
00255 #endif // __cplusplus <= 201103L
00256 
00257 #endif // _GLIBCXX_EXPERIMENTAL_MEMORY