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

   1 // array allocator -*- C++ -*-
   2
   3 // Copyright (C) 2004, 2005 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  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
  42 namespace __gnu_cxx
  43 {
  44   /// @brief  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 &__x; }
  59
  60       const_pointer
  61       address(const_reference __x) const { return &__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(__p) value_type(__val); }
  78
  79       void
  80       destroy(pointer __p) { __p->~_Tp(); }
  81     };
  82
  83   /**
  84    *  @brief  An allocator that uses previously allocated memory.
  85    *  This memory can be externally, globally, or otherwise allocated.
  86    */
  87   template<typename _Tp, typename _Array = std::tr1::array<_Tp> >
  88     class array_allocator : public array_allocator_base<_Tp>
  89     {
  90     public:
  91       typedef size_t     size_type;
  92       typedef ptrdiff_t  difference_type;
  93       typedef _Tp*       pointer;
  94       typedef const _Tp* const_pointer;
  95       typedef _Tp&       reference;
  96       typedef const _Tp& const_reference;
  97       typedef _Tp        value_type;
  98
  99       typedef _Array    array_type;
 100
 101       array_type* _M_array;
 102
 103      template<typename _Tp1, typename _Array1 = _Array>
 104         struct rebind
 105         { typedef array_allocator<_Tp1, _Array1> other; };
 106
 107       array_allocator(array_type* __array = NULL) throw()
 108       : _M_array(__array)
 109       { }
 110
 111       array_allocator(const array_allocator& __o)  throw()
 112       : _M_array(__o._M_array) { }
 113
 114       template<typename _Tp1, typename _Array1>
 115         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
 116         : _M_array(NULL) { }
 117
 118       ~array_allocator() throw() { }
 119
 120       pointer
 121       allocate(size_type __n, const void* = 0)
 122       {
 123         static size_type __array_used;
 124         if (_M_array == 0 || __array_used + __n > _M_array->size())
 125           std::__throw_bad_alloc();
 126         pointer __ret = _M_array->begin() + __array_used;
 127         __array_used += __n;
 128         return __ret;
 129       }
 130     };
 131
 132   template<typename _Tp, typename _Array>
 133     inline bool
 134     operator==(const array_allocator<_Tp, _Array>&,
 135                const array_allocator<_Tp, _Array>&)
 136     { return true; }
 137
 138   template<typename _Tp, typename _Array>
 139     inline bool
 140     operator!=(const array_allocator<_Tp, _Array>&,
 141                const array_allocator<_Tp, _Array>&)
 142     { return false; }
 143 } // namespace __gnu_cxx
 144
 145 #endif