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

   1 // array allocator -*- C++ -*-
   2
   3 // Copyright (C) 2004, 2005, 2006, 2007, 2008 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /** @file ext/array_allocator.h
  31  *  This file is a GNU extension to the Standard C++ Library.
  32  */
  33
  34 #ifndef _ARRAY_ALLOCATOR_H
  35 #define _ARRAY_ALLOCATOR_H 1
  36
  37 #include <cstddef>
  38 #include <new>
  39 #include <bits/functexcept.h>
  40 #include <tr1/array>
  41 #include <bits/move.h>
  42
  43 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  44
  45  using std::size_t;
  46  using std::ptrdiff_t;
  47
  48   /// Base class.
  49  template<typename _Tp>
  50     class array_allocator_base
  51     {
  52     public:
  53       typedef size_t            size_type;
  54       typedef ptrdiff_t         difference_type;
  55       typedef _Tp*              pointer;
  56       typedef const _Tp*        const_pointer;
  57       typedef _Tp&              reference;
  58       typedef const _Tp&        const_reference;
  59       typedef _Tp               value_type;
  60
  61       pointer
  62       address(reference __x) const { return &__x; }
  63
  64       const_pointer
  65       address(const_reference __x) const { return &__x; }
  66
  67       void
  68       deallocate(pointer, size_type)
  69       {
  70         // Does nothing.
  71       }
  72
  73       size_type
  74       max_size() const throw()
  75       { return size_t(-1) / sizeof(_Tp); }
  76
  77       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  78       // 402. wrong new expression in [some_] allocator::construct
  79       void
  80       construct(pointer __p, const _Tp& __val)
  81       { ::new((void *)__p) value_type(__val); }
  82
  83 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  84       template<typename... _Args>
  85         void
  86         construct(pointer __p, _Args&&... __args)
  87         { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
  88 #endif
  89
  90       void
  91       destroy(pointer __p) { __p->~_Tp(); }
  92     };
  93
  94   /**
  95    *  @brief  An allocator that uses previously allocated memory.
  96    *  This memory can be externally, globally, or otherwise allocated.
  97    */
  98   template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
  99     class array_allocator : public array_allocator_base<_Tp>
 100     {
 101     public:
 102       typedef size_t            size_type;
 103       typedef ptrdiff_t         difference_type;
 104       typedef _Tp*              pointer;
 105       typedef const _Tp*        const_pointer;
 106       typedef _Tp&              reference;
 107       typedef const _Tp&        const_reference;
 108       typedef _Tp               value_type;
 109       typedef _Array            array_type;
 110
 111     private:
 112       array_type*       _M_array;
 113       size_type         _M_used;
 114
 115     public:
 116      template<typename _Tp1, typename _Array1 = _Array>
 117         struct rebind
 118         { typedef array_allocator<_Tp1, _Array1> other; };
 119
 120       array_allocator(array_type* __array = NULL) throw()
 121       : _M_array(__array), _M_used(size_type()) { }
 122
 123       array_allocator(const array_allocator& __o)  throw()
 124       : _M_array(__o._M_array), _M_used(__o._M_used) { }
 125
 126       template<typename _Tp1, typename _Array1>
 127         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
 128         : _M_array(NULL), _M_used(size_type()) { }
 129
 130       ~array_allocator() throw() { }
 131
 132       pointer
 133       allocate(size_type __n, const void* = 0)
 134       {
 135         if (_M_array == 0 || _M_used + __n > _M_array->size())
 136           std::__throw_bad_alloc();
 137         pointer __ret = _M_array->begin() + _M_used;
 138         _M_used += __n;
 139         return __ret;
 140       }
 141     };
 142
 143   template<typename _Tp, typename _Array>
 144     inline bool
 145     operator==(const array_allocator<_Tp, _Array>&,
 146                const array_allocator<_Tp, _Array>&)
 147     { return true; }
 148
 149   template<typename _Tp, typename _Array>
 150     inline bool
 151     operator!=(const array_allocator<_Tp, _Array>&,
 152                const array_allocator<_Tp, _Array>&)
 153     { return false; }
 154
 155 _GLIBCXX_END_NAMESPACE
 156
 157 #endif