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, 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
  42 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  43
  44  using std::size_t;
  45  using std::ptrdiff_t;
  46
  47   /// @brief  Base class.
  48  template<typename _Tp>
  49     class array_allocator_base
  50     {
  51     public:
  52       typedef size_t     size_type;
  53       typedef ptrdiff_t  difference_type;
  54       typedef _Tp*       pointer;
  55       typedef const _Tp* const_pointer;
  56       typedef _Tp&       reference;
  57       typedef const _Tp& const_reference;
  58       typedef _Tp        value_type;
  59
  60       pointer
  61       address(reference __x) const { return &__x; }
  62
  63       const_pointer
  64       address(const_reference __x) const { return &__x; }
  65
  66       void
  67       deallocate(pointer, size_type)
  68       {
  69         // Does nothing.
  70       }
  71
  72       size_type
  73       max_size() const throw()
  74       { return size_t(-1) / sizeof(_Tp); }
  75
  76       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  77       // 402. wrong new expression in [some_] allocator::construct
  78       void
  79       construct(pointer __p, const _Tp& __val)
  80       { ::new(__p) value_type(__val); }
  81
  82       void
  83       destroy(pointer __p) { __p->~_Tp(); }
  84     };
  85
  86   /**
  87    *  @brief  An allocator that uses previously allocated memory.
  88    *  This memory can be externally, globally, or otherwise allocated.
  89    */
  90   template<typename _Tp, typename _Array = std::tr1::array<_Tp> >
  91     class array_allocator : public array_allocator_base<_Tp>
  92     {
  93     public:
  94       typedef size_t     size_type;
  95       typedef ptrdiff_t  difference_type;
  96       typedef _Tp*       pointer;
  97       typedef const _Tp* const_pointer;
  98       typedef _Tp&       reference;
  99       typedef const _Tp& const_reference;
 100       typedef _Tp        value_type;
 101
 102       typedef _Array    array_type;
 103
 104       array_type* _M_array;
 105
 106      template<typename _Tp1, typename _Array1 = _Array>
 107         struct rebind
 108         { typedef array_allocator<_Tp1, _Array1> other; };
 109
 110       array_allocator(array_type* __array = NULL) throw()
 111       : _M_array(__array)
 112       { }
 113
 114       array_allocator(const array_allocator& __o)  throw()
 115       : _M_array(__o._M_array) { }
 116
 117       template<typename _Tp1, typename _Array1>
 118         array_allocator(const array_allocator<_Tp1, _Array1>&) throw()
 119         : _M_array(NULL) { }
 120
 121       ~array_allocator() throw() { }
 122
 123       pointer
 124       allocate(size_type __n, const void* = 0)
 125       {
 126         static size_type __array_used;
 127         if (_M_array == 0 || __array_used + __n > _M_array->size())
 128           std::__throw_bad_alloc();
 129         pointer __ret = _M_array->begin() + __array_used;
 130         __array_used += __n;
 131         return __ret;
 132       }
 133     };
 134
 135   template<typename _Tp, typename _Array>
 136     inline bool
 137     operator==(const array_allocator<_Tp, _Array>&,
 138                const array_allocator<_Tp, _Array>&)
 139     { return true; }
 140
 141   template<typename _Tp, typename _Array>
 142     inline bool
 143     operator!=(const array_allocator<_Tp, _Array>&,
 144                const array_allocator<_Tp, _Array>&)
 145     { return false; }
 146
 147 _GLIBCXX_END_NAMESPACE
 148
 149 #endif