libstdc++
ext/alloc_traits.h
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00001 // Allocator traits -*- C++ -*-
00002 
00003 // Copyright (C) 2011 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 ext/alloc_traits.h
00026  *  This file is a GNU extension to the Standard C++ Library.
00027  */
00028 
00029 #ifndef _EXT_ALLOC_TRAITS_H
00030 #define _EXT_ALLOC_TRAITS_H 1
00031 
00032 #pragma GCC system_header
00033 
00034 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00035 # include <bits/alloc_traits.h>
00036 #else
00037 # include <bits/allocator.h>  // for __alloc_swap
00038 #endif
00039 
00040 namespace std _GLIBCXX_VISIBILITY(default)
00041 {
00042 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00043   template<typename> struct allocator;
00044 _GLIBCXX_END_NAMESPACE_VERSION
00045 } // namespace
00046 
00047 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
00048 {
00049 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00050 
00051 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00052 template<typename _Alloc>
00053   struct __allocator_always_compares_equal
00054   { static const bool value = false; };
00055 
00056   template<typename _Tp>
00057     struct __allocator_always_compares_equal<std::allocator<_Tp>>
00058     { static const bool value = true; };
00059 
00060   template<typename, typename> struct array_allocator;
00061 
00062   template<typename _Tp, typename _Array>
00063     struct __allocator_always_compares_equal<array_allocator<_Tp, _Array>>
00064     { static const bool value = true; };
00065 
00066   template<typename> struct mt_allocator;
00067 
00068   template<typename _Tp>
00069     struct __allocator_always_compares_equal<mt_allocator<_Tp>>
00070     { static const bool value = true; };
00071 
00072   template<typename> struct new_allocator;
00073 
00074   template<typename _Tp>
00075     struct __allocator_always_compares_equal<new_allocator<_Tp>>
00076     { static const bool value = true; };
00077 
00078   template<typename> struct pool_allocator;
00079 
00080   template<typename _Tp>
00081     struct __allocator_always_compares_equal<pool_allocator<_Tp>>
00082     { static const bool value = true; };
00083 #endif
00084 
00085 /**
00086  * @brief  Uniform interface to C++98 and C++0x allocators.
00087  * @ingroup allocators
00088 */
00089 template<typename _Alloc>
00090   struct __alloc_traits
00091 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00092   : std::allocator_traits<_Alloc>
00093 #endif
00094   {
00095     typedef _Alloc allocator_type;
00096 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00097     typedef std::allocator_traits<_Alloc>           _Base_type;
00098     typedef typename _Base_type::value_type         value_type;
00099     typedef typename _Base_type::pointer            pointer;
00100     typedef typename _Base_type::const_pointer      const_pointer;
00101     typedef typename _Base_type::size_type          size_type;
00102     // C++0x allocators do not define reference or const_reference
00103     typedef value_type&                             reference;
00104     typedef const value_type&                       const_reference;
00105     using _Base_type::allocate;
00106     using _Base_type::deallocate;
00107     using _Base_type::construct;
00108     using _Base_type::destroy;
00109     using _Base_type::max_size;
00110 
00111   private:
00112     template<typename _Ptr>
00113       struct __is_custom_pointer
00114       : std::integral_constant<bool, std::is_same<pointer, _Ptr>::value
00115                                      && !std::is_pointer<_Ptr>::value>
00116       { };
00117 
00118   public:
00119     // overload construct for non-standard pointer types
00120     template<typename _Ptr, typename... _Args>
00121       static typename std::enable_if<__is_custom_pointer<_Ptr>::value>::type
00122       construct(_Alloc& __a, _Ptr __p, _Args&&... __args)
00123       {
00124     _Base_type::construct(__a, std::addressof(*__p),
00125                   std::forward<_Args>(__args)...);
00126       }
00127 
00128     // overload destroy for non-standard pointer types
00129     template<typename _Ptr>
00130       static typename std::enable_if<__is_custom_pointer<_Ptr>::value>::type
00131       destroy(_Alloc& __a, _Ptr __p)
00132       { _Base_type::destroy(__a, std::addressof(*__p)); }
00133 
00134     static _Alloc _S_select_on_copy(const _Alloc& __a)
00135     { return _Base_type::select_on_container_copy_construction(__a); }
00136 
00137     static void _S_on_swap(_Alloc& __a, _Alloc& __b)
00138     { std::__alloc_on_swap(__a, __b); }
00139 
00140     static constexpr bool _S_propagate_on_copy_assign()
00141     { return _Base_type::propagate_on_container_copy_assignment::value; }
00142 
00143     static constexpr bool _S_propagate_on_move_assign()
00144     { return _Base_type::propagate_on_container_move_assignment::value; }
00145 
00146     static constexpr bool _S_propagate_on_swap()
00147     { return _Base_type::propagate_on_container_swap::value; }
00148 
00149     static constexpr bool _S_always_equal()
00150     { return __allocator_always_compares_equal<_Alloc>::value; }
00151 
00152     static constexpr bool _S_nothrow_move()
00153     { return _S_propagate_on_move_assign() || _S_always_equal(); }
00154 
00155     static constexpr bool _S_nothrow_swap()
00156     {
00157       using std::swap;
00158       return !_S_propagate_on_swap()
00159         || noexcept(swap(std::declval<_Alloc&>(), std::declval<_Alloc&>()));
00160     }
00161 
00162     template<typename _Tp>
00163       struct rebind
00164       { typedef typename _Base_type::template rebind_alloc<_Tp> other; };
00165 #else
00166 
00167     typedef typename _Alloc::pointer                pointer;
00168     typedef typename _Alloc::const_pointer          const_pointer;
00169     typedef typename _Alloc::value_type             value_type;
00170     typedef typename _Alloc::reference              reference;
00171     typedef typename _Alloc::const_reference        const_reference;
00172     typedef typename _Alloc::size_type              size_type;
00173 
00174     static pointer
00175     allocate(_Alloc& __a, size_type __n)
00176     { return __a.allocate(__n); }
00177 
00178     static void deallocate(_Alloc& __a, pointer __p, size_type __n)
00179     { __a.deallocate(__p, __n); }
00180 
00181     template<typename _Tp>
00182       static void construct(_Alloc& __a, pointer __p, const _Tp& __arg)
00183       { __a.construct(__p, __arg); }
00184 
00185     static void destroy(_Alloc& __a, pointer __p)
00186     { __a.destroy(__p); }
00187 
00188     static size_type max_size(const _Alloc& __a)
00189     { return __a.max_size(); }
00190 
00191     static const _Alloc& _S_select_on_copy(const _Alloc& __a) { return __a; }
00192 
00193     static void _S_on_swap(_Alloc& __a, _Alloc& __b)
00194     {
00195       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00196       // 431. Swapping containers with unequal allocators.
00197       std::__alloc_swap<_Alloc>::_S_do_it(__a, __b);
00198     }
00199 
00200     template<typename _Tp>
00201       struct rebind
00202       { typedef typename _Alloc::template rebind<_Tp>::other other; };
00203 #endif
00204   };
00205 
00206 _GLIBCXX_END_NAMESPACE_VERSION
00207 } // namespace
00208 
00209 #endif