contrib/gcc-4.4/libstdc++-v3/include/ext/extptr_allocator.h

   1 // <extptr_allocator.h> -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009 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 /**
  26  * @file ext/extptr_allocator.h
  27  * @author Bob Walters
  28  *
  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.
  32  */
  33
  34 #ifndef _EXTPTR_ALLOCATOR_H
  35 #define _EXTPTR_ALLOCATOR_H 1
  36
  37 #include <memory>
  38 #include <limits>
  39 #include <ext/pointer.h>
  40
  41 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  42
  43   /**
  44    * @brief An example allocator which uses a non-standard pointer type.
  45    * @ingroup allocators
  46    *
  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.
  50    */
  51   template<typename _Tp>
  52     class _ExtPtr_allocator
  53     {
  54     public:
  55       typedef std::size_t     size_type;
  56       typedef std::ptrdiff_t  difference_type;
  57
  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> >
  61                                                              const_pointer;
  62
  63       typedef _Tp&       reference;
  64       typedef const _Tp& const_reference;
  65       typedef _Tp        value_type;
  66
  67       template<typename _Up>
  68         struct rebind
  69         { typedef _ExtPtr_allocator<_Up> other; };
  70
  71       _ExtPtr_allocator() throw()
  72       : _M_real_alloc() { }
  73
  74       _ExtPtr_allocator(const _ExtPtr_allocator &__rarg) throw()
  75       : _M_real_alloc(__rarg._M_real_alloc) { }
  76
  77       template<typename _Up>
  78         _ExtPtr_allocator(const _ExtPtr_allocator<_Up>& __rarg) throw()
  79         : _M_real_alloc(__rarg._M_getUnderlyingImp()) { }
  80
  81       ~_ExtPtr_allocator() throw()
  82       { }
  83
  84       pointer address(reference __x) const
  85       { return &__x; }
  86
  87       const_pointer address(const_reference __x) const
  88       { return &__x; }
  89
  90       pointer allocate(size_type __n, void* __hint = 0)
  91       { return _M_real_alloc.allocate(__n,__hint); }
  92
  93       void deallocate(pointer __p, size_type __n)
  94       { _M_real_alloc.deallocate(__p.get(), __n); }
  95
  96       size_type max_size() const throw()
  97       { return std::numeric_limits<size_type>::max() / sizeof(_Tp); }
  98
  99       void construct(pointer __p, const _Tp& __val)
 100       { ::new(__p.get()) _Tp(__val); }
 101
 102 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 103       template<typename... _Args>
 104         void
 105         construct(pointer __p, _Args&&... __args)
 106         { ::new(__p.get()) _Tp(std::forward<_Args>(__args)...); }
 107 #endif
 108
 109       void destroy(pointer __p)
 110       { __p->~_Tp(); }
 111
 112       template<typename _Up>
 113         inline bool
 114         operator==(const _ExtPtr_allocator<_Up>& __rarg)
 115         { return _M_real_alloc == __rarg._M_getUnderlyingImp(); }
 116
 117       inline bool
 118       operator==(const _ExtPtr_allocator& __rarg)
 119       { return _M_real_alloc == __rarg._M_real_alloc; }
 120
 121       template<typename _Up>
 122         inline bool
 123         operator!=(const _ExtPtr_allocator<_Up>& __rarg)
 124         { return _M_real_alloc != __rarg._M_getUnderlyingImp(); }
 125
 126       inline bool
 127       operator!=(const _ExtPtr_allocator& __rarg)
 128       { return _M_real_alloc != __rarg._M_real_alloc; }
 129
 130       template<typename _Up>
 131         inline friend void
 132         swap(_ExtPtr_allocator<_Up>&, _ExtPtr_allocator<_Up>&);
 133
 134       // A method specific to this implementation.
 135       const std::allocator<_Tp>&
 136       _M_getUnderlyingImp() const
 137       { return _M_real_alloc; }
 138
 139     private:
 140       std::allocator<_Tp>  _M_real_alloc;
 141     };
 142
 143   // _ExtPtr_allocator<void> specialization.
 144   template<>
 145     class _ExtPtr_allocator<void>
 146     {
 147     public:
 148       typedef std::size_t      size_type;
 149       typedef std::ptrdiff_t   difference_type;
 150       typedef void             value_type;
 151
 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> >
 155                                                               const_pointer;
 156
 157       template<typename _Up>
 158         struct rebind
 159         { typedef _ExtPtr_allocator<_Up> other; };
 160
 161     private:
 162       std::allocator<void>  _M_real_alloc;
 163     };
 164
 165   template<typename _Tp>
 166     inline void
 167     swap(_ExtPtr_allocator<_Tp>& __larg, _ExtPtr_allocator<_Tp>& __rarg)
 168     {
 169       std::allocator<_Tp> __tmp( __rarg._M_real_alloc );
 170       __rarg._M_real_alloc = __larg._M_real_alloc;
 171       __larg._M_real_alloc = __tmp;
 172     }
 173
 174 _GLIBCXX_END_NAMESPACE
 175
 176 #endif /* _EXTPTR_ALLOCATOR_H */