libstdc++-v3/include/ext/array_allocator.h

   1 // array allocator -*- C++ -*-
   2
   3 // Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /** @file ext/array_allocator.h
  27  *  This file is a GNU extension to the Standard C++ Library.
  28  */
  29
  30 #ifndef _ARRAY_ALLOCATOR_H
  31 #define _ARRAY_ALLOCATOR_H 1
  32
  33 #include <bits/c++config.h>
  34 #include <new>
  35 #include <bits/functexcept.h>
  36 #include <tr1/array>
  37 #include <bits/move.h>
  38
  39 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  40
  41  using std::size_t;
  42  using std::ptrdiff_t;
  43
  44   /// Base class.
  45  template<typename _Tp>
  46     class array_allocator_base
  47     {
  48     public:
  49       typedef size_t            size_type;
  50       typedef ptrdiff_t         difference_type;
  51       typedef _Tp*              pointer;
  52       typedef const _Tp*        const_pointer;
  53       typedef _Tp&              reference;
  54       typedef const _Tp&        const_reference;
  55       typedef _Tp               value_type;
  56
  57       pointer
  58       address(reference __x) const { return std::__addressof(__x); }
  59
  60       const_pointer
  61       address(const_reference __x) const { return std::__addressof(__x); }
  62
  63       void
  64       deallocate(pointer, size_type)
  65       {
  66         // Does nothing.
  67       }
  68
  69       size_type
  70       max_size() const throw()
  71       { return size_t(-1) / sizeof(_Tp); }
  72
  73       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  74       // 402. wrong new expression in [some_] allocator::construct
  75       void
  76       construct(pointer __p, const _Tp& __val)
  77       { ::new((void *)__p) value_type(__val); }
  78
  79 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  80       template<typename... _Args>
  81         void
  82         construct(pointer __p, _Args&&... __args)
  83         { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
  84 #endif
  85
  86       void
  87       destroy(pointer __p) { __p->~_Tp(); }
  88     };
  89
  90   /**
  91    *  @brief  An allocator that uses previously allocated memory.
  92    *  This memory can be externally, globally, or otherwise allocated.
  93    *  @ingroup allocators
  94    */
  95   template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
  96     class array_allocator : public array_allocator_base<_Tp>
  97     {
  98     public:
  99       typedef size_t            size_type;
 100       typedef ptrdiff_t         difference_type;
 101       typedef _Tp*              pointer;
 102       typedef const _Tp*        const_pointer;
 103       typedef _Tp&              reference;
 104       typedef const _Tp&        const_reference;
 105       typedef _Tp               value_type;
 106       typedef _Array            array_type;
 107
 108     private:
 109       array_type*       _M_array;
 110       size_type         _M_used;
 111
 112     public:
 113      template<typename _Tp1, typename _Array1 = _Array>
 114         struct rebind
 115         { typedef array_allocator<_Tp1, _Array1> other; };
 116
 117       array_allocator(array_type* __array = 0) throw()
 118       : _M_array(__array), _M_used(size_type()) { }
 119
 120       array_allocator(const array_allocator& __o)  throw()
 121       : _M_array(__o._M_array), _M_used(__o._M_used) { }
 122
 123       template<typename _Tp1, typename _Array1>
 124         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
 125         : _M_array(0), _M_used(size_type()) { }
 126
 127       ~array_allocator() throw() { }
 128
 129       pointer
 130       allocate(size_type __n, const void* = 0)
 131       {
 132         if (_M_array == 0 || _M_used + __n > _M_array->size())
 133           std::__throw_bad_alloc();
 134         pointer __ret = _M_array->begin() + _M_used;
 135         _M_used += __n;
 136         return __ret;
 137       }
 138     };
 139
 140   template<typename _Tp, typename _Array>
 141     inline bool
 142     operator==(const array_allocator<_Tp, _Array>&,
 143                const array_allocator<_Tp, _Array>&)
 144     { return true; }
 145
 146   template<typename _Tp, typename _Array>
 147     inline bool
 148     operator!=(const array_allocator<_Tp, _Array>&,
 149                const array_allocator<_Tp, _Array>&)
 150     { return false; }
 151
 152 _GLIBCXX_END_NAMESPACE
 153
 154 #endif