1 // <extptr_allocator.h> -*- C++ -*-
3 // Copyright (C) 2008, 2009 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
29 * An example allocator which uses an alternative pointer type from
30 * bits/pointer.h. Supports test cases which confirm container support
31 * for alternative pointers.
34 #ifndef _EXTPTR_ALLOCATOR_H
35 #define _EXTPTR_ALLOCATOR_H 1
39 #include <ext/pointer.h>
41 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx
)
44 * @brief An example allocator which uses a non-standard pointer type.
47 * This allocator specifies that containers use a 'relative pointer' as it's
48 * pointer type. (See ext/pointer.h) Memory allocation in this example
49 * is still performed using std::allocator.
51 template<typename _Tp
>
52 class _ExtPtr_allocator
55 typedef std::size_t size_type
;
56 typedef std::ptrdiff_t difference_type
;
58 // Note the non-standard pointer types.
59 typedef _Pointer_adapter
<_Relative_pointer_impl
<_Tp
> > pointer
;
60 typedef _Pointer_adapter
<_Relative_pointer_impl
<const _Tp
> >
63 typedef _Tp
& reference
;
64 typedef const _Tp
& const_reference
;
65 typedef _Tp value_type
;
67 template<typename _Up
>
69 { typedef _ExtPtr_allocator
<_Up
> other
; };
71 _ExtPtr_allocator() throw()
74 _ExtPtr_allocator(const _ExtPtr_allocator
&__rarg
) throw()
75 : _M_real_alloc(__rarg
._M_real_alloc
) { }
77 template<typename _Up
>
78 _ExtPtr_allocator(const _ExtPtr_allocator
<_Up
>& __rarg
) throw()
79 : _M_real_alloc(__rarg
._M_getUnderlyingImp()) { }
81 ~_ExtPtr_allocator() throw()
84 pointer
address(reference __x
) const
87 const_pointer
address(const_reference __x
) const
90 pointer
allocate(size_type __n
, void* __hint
= 0)
91 { return _M_real_alloc
.allocate(__n
,__hint
); }
93 void deallocate(pointer __p
, size_type __n
)
94 { _M_real_alloc
.deallocate(__p
.get(), __n
); }
96 size_type
max_size() const throw()
97 { return std::numeric_limits
<size_type
>::max() / sizeof(_Tp
); }
99 void construct(pointer __p
, const _Tp
& __val
)
100 { ::new(__p
.get()) _Tp(__val
); }
102 #ifdef __GXX_EXPERIMENTAL_CXX0X__
103 template<typename
... _Args
>
105 construct(pointer __p
, _Args
&&... __args
)
106 { ::new(__p
.get()) _Tp(std::forward
<_Args
>(__args
)...); }
109 void destroy(pointer __p
)
112 template<typename _Up
>
114 operator==(const _ExtPtr_allocator
<_Up
>& __rarg
)
115 { return _M_real_alloc
== __rarg
._M_getUnderlyingImp(); }
118 operator==(const _ExtPtr_allocator
& __rarg
)
119 { return _M_real_alloc
== __rarg
._M_real_alloc
; }
121 template<typename _Up
>
123 operator!=(const _ExtPtr_allocator
<_Up
>& __rarg
)
124 { return _M_real_alloc
!= __rarg
._M_getUnderlyingImp(); }
127 operator!=(const _ExtPtr_allocator
& __rarg
)
128 { return _M_real_alloc
!= __rarg
._M_real_alloc
; }
130 template<typename _Up
>
132 swap(_ExtPtr_allocator
<_Up
>&, _ExtPtr_allocator
<_Up
>&);
134 // A method specific to this implementation.
135 const std::allocator
<_Tp
>&
136 _M_getUnderlyingImp() const
137 { return _M_real_alloc
; }
140 std::allocator
<_Tp
> _M_real_alloc
;
143 // _ExtPtr_allocator<void> specialization.
145 class _ExtPtr_allocator
<void>
148 typedef std::size_t size_type
;
149 typedef std::ptrdiff_t difference_type
;
150 typedef void value_type
;
152 // Note the non-standard pointer types
153 typedef _Pointer_adapter
<_Relative_pointer_impl
<void> > pointer
;
154 typedef _Pointer_adapter
<_Relative_pointer_impl
<const void> >
157 template<typename _Up
>
159 { typedef _ExtPtr_allocator
<_Up
> other
; };
162 std::allocator
<void> _M_real_alloc
;
165 template<typename _Tp
>
167 swap(_ExtPtr_allocator
<_Tp
>& __larg
, _ExtPtr_allocator
<_Tp
>& __rarg
)
169 std::allocator
<_Tp
> __tmp( __rarg
._M_real_alloc
);
170 __rarg
._M_real_alloc
= __larg
._M_real_alloc
;
171 __larg
._M_real_alloc
= __tmp
;
174 _GLIBCXX_END_NAMESPACE
176 #endif /* _EXTPTR_ALLOCATOR_H */