libstdc++-v3/include/bits/allocator.h

   1 // Allocators -*- C++ -*-
   2
   3 // Copyright (C) 2001-2012 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /*
  26  * Copyright (c) 1996-1997
  27  * Silicon Graphics Computer Systems, Inc.
  28  *
  29  * Permission to use, copy, modify, distribute and sell this software
  30  * and its documentation for any purpose is hereby granted without fee,
  31  * provided that the above copyright notice appear in all copies and
  32  * that both that copyright notice and this permission notice appear
  33  * in supporting documentation.  Silicon Graphics makes no
  34  * representations about the suitability of this software for any
  35  * purpose.  It is provided "as is" without express or implied warranty.
  36  */
  37
  38 /** @file bits/allocator.h
  39  *  This is an internal header file, included by other library headers.
  40  *  Do not attempt to use it directly. @headername{memory}
  41  */
  42
  43 #ifndef _ALLOCATOR_H
  44 #define _ALLOCATOR_H 1
  45
  46 // Define the base class to std::allocator.
  47 #include <bits/c++allocator.h>
  48 #if __cplusplus >= 201103L
  49 #include <type_traits>
  50 #endif
  51
  52 namespace std _GLIBCXX_VISIBILITY(default)
  53 {
  54 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  55
  56   /**
  57    * @defgroup allocators Allocators
  58    * @ingroup memory
  59    *
  60    * Classes encapsulating memory operations.
  61    *
  62    * @{
  63    */
  64
  65   template<typename _Tp>
  66     class allocator;
  67
  68   /// allocator<void> specialization.
  69   template<>
  70     class allocator<void>
  71     {
  72     public:
  73       typedef size_t      size_type;
  74       typedef ptrdiff_t   difference_type;
  75       typedef void*       pointer;
  76       typedef const void* const_pointer;
  77       typedef void        value_type;
  78
  79       template<typename _Tp1>
  80         struct rebind
  81         { typedef allocator<_Tp1> other; };
  82
  83 #if __cplusplus >= 201103L
  84       // _GLIBCXX_RESOLVE_LIB_DEFECTS
  85       // 2103. std::allocator propagate_on_container_move_assignment
  86       typedef true_type propagate_on_container_move_assignment;
  87 #endif
  88     };
  89
  90   /**
  91    * @brief  The @a standard allocator, as per [20.4].
  92    *
  93    *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
  94    *  for further details.
  95    *
  96    *  @tparam  _Tp  Type of allocated object.
  97    */
  98   template<typename _Tp>
  99     class allocator: public __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
 110       template<typename _Tp1>
 111         struct rebind
 112         { typedef allocator<_Tp1> other; };
 113
 114 #if __cplusplus >= 201103L
 115       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 116       // 2103. std::allocator propagate_on_container_move_assignment
 117       typedef true_type propagate_on_container_move_assignment;
 118 #endif
 119
 120       allocator() throw() { }
 121
 122       allocator(const allocator& __a) throw()
 123       : __allocator_base<_Tp>(__a) { }
 124
 125       template<typename _Tp1>
 126         allocator(const allocator<_Tp1>&) throw() { }
 127
 128       ~allocator() throw() { }
 129
 130       // Inherit everything else.
 131     };
 132
 133   template<typename _T1, typename _T2>
 134     inline bool
 135     operator==(const allocator<_T1>&, const allocator<_T2>&)
 136     { return true; }
 137
 138   template<typename _Tp>
 139     inline bool
 140     operator==(const allocator<_Tp>&, const allocator<_Tp>&)
 141     { return true; }
 142
 143   template<typename _T1, typename _T2>
 144     inline bool
 145     operator!=(const allocator<_T1>&, const allocator<_T2>&)
 146     { return false; }
 147
 148   template<typename _Tp>
 149     inline bool
 150     operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
 151     { return false; }
 152
 153   /// Declare uses_allocator so it can be specialized in \<queue\> etc.
 154   template<typename, typename>
 155     struct uses_allocator;
 156
 157   /**
 158    * @}
 159    */
 160
 161   // Inhibit implicit instantiations for required instantiations,
 162   // which are defined via explicit instantiations elsewhere.
 163 #if _GLIBCXX_EXTERN_TEMPLATE
 164   extern template class allocator<char>;
 165   extern template class allocator<wchar_t>;
 166 #endif
 167
 168   // Undefine.
 169 #undef __allocator_base
 170
 171   // To implement Option 3 of DR 431.
 172   template<typename _Alloc, bool = __is_empty(_Alloc)>
 173     struct __alloc_swap
 174     { static void _S_do_it(_Alloc&, _Alloc&) { } };
 175
 176   template<typename _Alloc>
 177     struct __alloc_swap<_Alloc, false>
 178     {
 179       static void
 180       _S_do_it(_Alloc& __one, _Alloc& __two)
 181       {
 182         // Precondition: swappable allocators.
 183         if (__one != __two)
 184           swap(__one, __two);
 185       }
 186     };
 187
 188   // Optimize for stateless allocators.
 189   template<typename _Alloc, bool = __is_empty(_Alloc)>
 190     struct __alloc_neq
 191     {
 192       static bool
 193       _S_do_it(const _Alloc&, const _Alloc&)
 194       { return false; }
 195     };
 196
 197   template<typename _Alloc>
 198     struct __alloc_neq<_Alloc, false>
 199     {
 200       static bool
 201       _S_do_it(const _Alloc& __one, const _Alloc& __two)
 202       { return __one != __two; }
 203     };
 204
 205 #if __cplusplus >= 201103L
 206   template<typename _Tp, bool
 207     = __or_<is_copy_constructible<typename _Tp::value_type>,
 208             is_nothrow_move_constructible<typename _Tp::value_type>>::value>
 209     struct __shrink_to_fit_aux
 210     { static bool _S_do_it(_Tp&) { return false; } };
 211
 212   template<typename _Tp>
 213     struct __shrink_to_fit_aux<_Tp, true>
 214     {
 215       static bool
 216       _S_do_it(_Tp& __c)
 217       {
 218         __try
 219           {
 220             _Tp(__make_move_if_noexcept_iterator(__c.begin()),
 221                 __make_move_if_noexcept_iterator(__c.end()),
 222                 __c.get_allocator()).swap(__c);
 223             return true;
 224           }
 225         __catch(...)
 226           { return false; }
 227       }
 228     };
 229 #endif
 230
 231 _GLIBCXX_END_NAMESPACE_VERSION
 232 } // namespace std
 233
 234 #endif