gomp-20050608-branch/libstdc++-v3/include/bits/allocator.h

   1 // Allocators -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
   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 2, 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 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /*
  32  * Copyright (c) 1996-1997
  33  * Silicon Graphics Computer Systems, Inc.
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Silicon Graphics makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  */
  43
  44 /** @file allocator.h
  45  *  This is an internal header file, included by other library headers.
  46  *  You should not attempt to use it directly.
  47  */
  48
  49 #ifndef _ALLOCATOR_H
  50 #define _ALLOCATOR_H 1
  51
  52 // Define the base class to std::allocator.
  53 #include <bits/c++allocator.h>
  54
  55 #include <bits/cpp_type_traits.h> // for __is_empty
  56
  57 _GLIBCXX_BEGIN_NAMESPACE(std)
  58
  59   template<typename _Tp>
  60     class allocator;
  61
  62   /// allocator<void> specialization.
  63   template<>
  64     class allocator<void>
  65     {
  66     public:
  67       typedef size_t      size_type;
  68       typedef ptrdiff_t   difference_type;
  69       typedef void*       pointer;
  70       typedef const void* const_pointer;
  71       typedef void        value_type;
  72
  73       template<typename _Tp1>
  74         struct rebind
  75         { typedef allocator<_Tp1> other; };
  76     };
  77
  78   /**
  79    * @brief  The "standard" allocator, as per [20.4].
  80    *
  81    *  Further details:
  82    *  http://gcc.gnu.org/onlinedocs/libstdc++/20_util/allocator.html
  83    */
  84   template<typename _Tp>
  85     class allocator: public __glibcxx_base_allocator<_Tp>
  86     {
  87    public:
  88       typedef size_t     size_type;
  89       typedef ptrdiff_t  difference_type;
  90       typedef _Tp*       pointer;
  91       typedef const _Tp* const_pointer;
  92       typedef _Tp&       reference;
  93       typedef const _Tp& const_reference;
  94       typedef _Tp        value_type;
  95
  96       template<typename _Tp1>
  97         struct rebind
  98         { typedef allocator<_Tp1> other; };
  99
 100       allocator() throw() { }
 101
 102       allocator(const allocator& __a) throw()
 103       : __glibcxx_base_allocator<_Tp>(__a) { }
 104
 105       template<typename _Tp1>
 106         allocator(const allocator<_Tp1>&) throw() { }
 107
 108       ~allocator() throw() { }
 109
 110       // Inherit everything else.
 111     };
 112
 113   template<typename _T1, typename _T2>
 114     inline bool
 115     operator==(const allocator<_T1>&, const allocator<_T2>&)
 116     { return true; }
 117
 118   template<typename _T1, typename _T2>
 119     inline bool
 120     operator!=(const allocator<_T1>&, const allocator<_T2>&)
 121     { return false; }
 122
 123   // Inhibit implicit instantiations for required instantiations,
 124   // which are defined via explicit instantiations elsewhere.
 125   // NB: This syntax is a GNU extension.
 126 #if _GLIBCXX_EXTERN_TEMPLATE
 127   extern template class allocator<char>;
 128   extern template class allocator<wchar_t>;
 129 #endif
 130
 131   // Undefine.
 132 #undef __glibcxx_base_allocator
 133
 134   // To implement Option 3 of DR 431.
 135   template<typename _Alloc, bool = std::__is_empty<_Alloc>::__value>
 136     struct __alloc_swap
 137     { static void _S_do_it(_Alloc&, _Alloc&) { } };
 138
 139   template<typename _Alloc>
 140     struct __alloc_swap<_Alloc, false>
 141     {
 142       static void
 143       _S_do_it(_Alloc& __one, _Alloc& __two)
 144       {
 145         // Precondition: swappable allocators.
 146         if (__one != __two)
 147           swap(__one, __two);
 148       }
 149     };
 150
 151 _GLIBCXX_END_NAMESPACE
 152
 153 #endif