# allocator.h

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    00001 // Allocators -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 2, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 /*
    00032  * Copyright (c) 1996-1997
    00033  * Silicon Graphics Computer Systems, Inc.
    00034  *
    00035  * Permission to use, copy, modify, distribute and sell this software
    00036  * and its documentation for any purpose is hereby granted without fee,
    00037  * provided that the above copyright notice appear in all copies and
    00038  * that both that copyright notice and this permission notice appear
    00039  * in supporting documentation.  Silicon Graphics makes no
    00040  * representations about the suitability of this software for any
    00041  * purpose.  It is provided "as is" without express or implied warranty.
    00042  */
    00043
    00044 /** @file allocator.h
    00045  *  This is an internal header file, included by other library headers.
    00046  *  You should not attempt to use it directly.
    00047  */
    00048
    00049 #ifndef _ALLOCATOR_H
    00050 #define _ALLOCATOR_H 1
    00051
    00052 // Define the base class to std::allocator.
    00053 #include <bits/c++allocator.h>
    00054
    00055 _GLIBCXX_BEGIN_NAMESPACE(std)
    00056
    00057   template<typename _Tp>
    00058     class allocator;
    00059
    00060   /// allocator<void> specialization.
    00061   template<>
    00062     class allocator<void>
    00063     {
    00064     public:
    00065       typedef size_t      size_type;
    00066       typedef ptrdiff_t   difference_type;
    00067       typedef void*       pointer;
    00068       typedef const void* const_pointer;
    00069       typedef void        value_type;
    00070
    00071       template<typename _Tp1>
    00072         struct rebind
    00073         { typedef allocator<_Tp1> other; };
    00074     };
    00075
    00076   /**
    00077    * @brief  The "standard" allocator, as per [20.4].
    00078    *
    00079    *  Further details:
    00080    *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
    00081    */
    00082   template<typename _Tp>
    00083     class allocator: public __glibcxx_base_allocator<_Tp>
    00084     {
    00085    public:
    00086       typedef size_t     size_type;
    00087       typedef ptrdiff_t  difference_type;
    00088       typedef _Tp*       pointer;
    00089       typedef const _Tp* const_pointer;
    00090       typedef _Tp&       reference;
    00091       typedef const _Tp& const_reference;
    00092       typedef _Tp        value_type;
    00093
    00094       template<typename _Tp1>
    00095         struct rebind
    00096         { typedef allocator<_Tp1> other; };
    00097
    00098       allocator() throw() { }
    00099
    00100       allocator(const allocator& __a) throw()
    00101       : __glibcxx_base_allocator<_Tp>(__a) { }
    00102
    00103       template<typename _Tp1>
    00104         allocator(const allocator<_Tp1>&) throw() { }
    00105
    00106       ~allocator() throw() { }
    00107
    00108       // Inherit everything else.
    00109     };
    00110
    00111   template<typename _T1, typename _T2>
    00112     inline bool
    00113     operator==(const allocator<_T1>&, const allocator<_T2>&)
    00114     { return true; }
    00115
    00116   template<typename _Tp>
    00117     inline bool
    00118     operator==(const allocator<_Tp>&, const allocator<_Tp>&)
    00119     { return true; }
    00120
    00121   template<typename _T1, typename _T2>
    00122     inline bool
    00123     operator!=(const allocator<_T1>&, const allocator<_T2>&)
    00124     { return false; }
    00125
    00126   template<typename _Tp>
    00127     inline bool
    00128     operator!=(const allocator<_Tp>&, const allocator<_Tp>&)
    00129     { return false; }
    00130
    00131   // Inhibit implicit instantiations for required instantiations,
    00132   // which are defined via explicit instantiations elsewhere.
    00133   // NB: This syntax is a GNU extension.
    00134 #if _GLIBCXX_EXTERN_TEMPLATE
    00135   extern template class allocator<char>;
    00136   extern template class allocator<wchar_t>;
    00137 #endif
    00138
    00139   // Undefine.
    00140 #undef __glibcxx_base_allocator
    00141
    00142   // To implement Option 3 of DR 431.
    00143   template<typename _Alloc, bool = __is_empty(_Alloc)>
    00144     struct __alloc_swap
    00145     { static void _S_do_it(_Alloc&, _Alloc&) { } };
    00146
    00147   template<typename _Alloc>
    00148     struct __alloc_swap<_Alloc, false>
    00149     {
    00150       static void
    00151       _S_do_it(_Alloc& __one, _Alloc& __two)
    00152       {
    00153     // Precondition: swappable allocators.
    00154     if (__one != __two)
    00155       swap(__one, __two);
    00156       }
    00157     };
    00158
    00159   // Optimize for stateless allocators.
    00160   template<typename _Alloc, bool = __is_empty(_Alloc)>
    00161     struct __alloc_neq
    00162     {
    00163       static bool
    00164       _S_do_it(const _Alloc&, const _Alloc&)
    00165       { return false; }
    00166     };
    00167
    00168   template<typename _Alloc>
    00169     struct __alloc_neq<_Alloc, false>
    00170     {
    00171       static bool
    00172       _S_do_it(const _Alloc& __one, const _Alloc& __two)
    00173       { return __one != __two; }
    00174     };
    00175
    00176 _GLIBCXX_END_NAMESPACE
    00177
    00178 #endif