1 // <extptr_allocator.h> -*- C++ -*-
3 // Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
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)
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.
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.
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/>.
26 * @file ext/extptr_allocator.h
27 * This file is a GNU extension to the Standard C++ Library.
31 * An example allocator which uses an alternative pointer type from
32 * bits/pointer.h. Supports test cases which confirm container support
33 * for alternative pointers.
36 #ifndef _EXTPTR_ALLOCATOR_H
37 #define _EXTPTR_ALLOCATOR_H 1
41 #include <ext/pointer.h>
43 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
48 * @brief An example allocator which uses a non-standard pointer type.
51 * This allocator specifies that containers use a 'relative pointer' as it's
52 * pointer type. (See ext/pointer.h) Memory allocation in this example
53 * is still performed using std::allocator.
55 template<typename _Tp>
56 class _ExtPtr_allocator
59 typedef std::size_t size_type;
60 typedef std::ptrdiff_t difference_type;
62 // Note the non-standard pointer types.
63 typedef _Pointer_adapter<_Relative_pointer_impl<_Tp> > pointer;
64 typedef _Pointer_adapter<_Relative_pointer_impl<const _Tp> >
67 typedef _Tp& reference;
68 typedef const _Tp& const_reference;
69 typedef _Tp value_type;
71 template<typename _Up>
73 { typedef _ExtPtr_allocator<_Up> other; };
75 _ExtPtr_allocator() throw()
78 _ExtPtr_allocator(const _ExtPtr_allocator &__rarg) throw()
79 : _M_real_alloc(__rarg._M_real_alloc) { }
81 template<typename _Up>
82 _ExtPtr_allocator(const _ExtPtr_allocator<_Up>& __rarg) throw()
83 : _M_real_alloc(__rarg._M_getUnderlyingImp()) { }
85 ~_ExtPtr_allocator() throw()
88 pointer address(reference __x) const
89 { return std::__addressof(__x); }
91 const_pointer address(const_reference __x) const
92 { return std::__addressof(__x); }
94 pointer allocate(size_type __n, void* __hint = 0)
95 { return _M_real_alloc.allocate(__n,__hint); }
97 void deallocate(pointer __p, size_type __n)
98 { _M_real_alloc.deallocate(__p.get(), __n); }
100 size_type max_size() const throw()
101 { return std::numeric_limits<size_type>::max() / sizeof(_Tp); }
103 void construct(pointer __p, const _Tp& __val)
104 { ::new(__p.get()) _Tp(__val); }
106 #ifdef __GXX_EXPERIMENTAL_CXX0X__
107 template<typename... _Args>
109 construct(pointer __p, _Args&&... __args)
110 { ::new(__p.get()) _Tp(std::forward<_Args>(__args)...); }
113 void destroy(pointer __p)
116 template<typename _Up>
118 operator==(const _ExtPtr_allocator<_Up>& __rarg)
119 { return _M_real_alloc == __rarg._M_getUnderlyingImp(); }
122 operator==(const _ExtPtr_allocator& __rarg)
123 { return _M_real_alloc == __rarg._M_real_alloc; }
125 template<typename _Up>
127 operator!=(const _ExtPtr_allocator<_Up>& __rarg)
128 { return _M_real_alloc != __rarg._M_getUnderlyingImp(); }
131 operator!=(const _ExtPtr_allocator& __rarg)
132 { return _M_real_alloc != __rarg._M_real_alloc; }
134 template<typename _Up>
136 swap(_ExtPtr_allocator<_Up>&, _ExtPtr_allocator<_Up>&);
138 // A method specific to this implementation.
139 const std::allocator<_Tp>&
140 _M_getUnderlyingImp() const
141 { return _M_real_alloc; }
144 std::allocator<_Tp> _M_real_alloc;
147 // _ExtPtr_allocator<void> specialization.
149 class _ExtPtr_allocator<void>
152 typedef std::size_t size_type;
153 typedef std::ptrdiff_t difference_type;
154 typedef void value_type;
156 // Note the non-standard pointer types
157 typedef _Pointer_adapter<_Relative_pointer_impl<void> > pointer;
158 typedef _Pointer_adapter<_Relative_pointer_impl<const void> >
161 template<typename _Up>
163 { typedef _ExtPtr_allocator<_Up> other; };
166 std::allocator<void> _M_real_alloc;
169 template<typename _Tp>
171 swap(_ExtPtr_allocator<_Tp>& __larg, _ExtPtr_allocator<_Tp>& __rarg)
173 std::allocator<_Tp> __tmp( __rarg._M_real_alloc );
174 __rarg._M_real_alloc = __larg._M_real_alloc;
175 __larg._M_real_alloc = __tmp;
178 _GLIBCXX_END_NAMESPACE_VERSION
181 #endif /* _EXTPTR_ALLOCATOR_H */