libstdc++
array_allocator.h
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00001 // array allocator -*- C++ -*-
00002 
00003 // Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /** @file ext/array_allocator.h
00027  *  This file is a GNU extension to the Standard C++ Library.
00028  */
00029 
00030 #ifndef _ARRAY_ALLOCATOR_H
00031 #define _ARRAY_ALLOCATOR_H 1
00032 
00033 #include <bits/c++config.h>
00034 #include <new>
00035 #include <bits/functexcept.h>
00036 #include <tr1/array>
00037 #include <bits/move.h>
00038 
00039 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
00040 {
00041 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00042 
00043  using std::size_t;
00044  using std::ptrdiff_t;
00045 
00046   /// Base class.
00047  template<typename _Tp>
00048     class array_allocator_base
00049     {
00050     public:
00051       typedef size_t        size_type;
00052       typedef ptrdiff_t     difference_type;
00053       typedef _Tp*          pointer;
00054       typedef const _Tp*    const_pointer;
00055       typedef _Tp&          reference;
00056       typedef const _Tp&    const_reference;
00057       typedef _Tp           value_type;
00058 
00059       pointer
00060       address(reference __x) const _GLIBCXX_NOEXCEPT
00061       { return std::__addressof(__x); }
00062 
00063       const_pointer
00064       address(const_reference __x) const _GLIBCXX_NOEXCEPT
00065       { return std::__addressof(__x); }
00066 
00067       void
00068       deallocate(pointer, size_type)
00069       { 
00070     // Does nothing.
00071       }
00072 
00073       size_type
00074       max_size() const _GLIBCXX_USE_NOEXCEPT 
00075       { return size_t(-1) / sizeof(_Tp); }
00076 
00077 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00078       template<typename _Up, typename... _Args>
00079         void
00080         construct(_Up* __p, _Args&&... __args)
00081     { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
00082 
00083       template<typename _Up>
00084         void 
00085         destroy(_Up* __p) { __p->~_Up(); }
00086 #else
00087       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00088       // 402. wrong new expression in [some_] allocator::construct
00089       void 
00090       construct(pointer __p, const _Tp& __val) 
00091       { ::new((void *)__p) value_type(__val); }
00092 
00093       void 
00094       destroy(pointer __p) { __p->~_Tp(); }
00095 #endif
00096     };  
00097 
00098   /**
00099    *  @brief  An allocator that uses previously allocated memory.
00100    *  This memory can be externally, globally, or otherwise allocated.
00101    *  @ingroup allocators
00102    */
00103   template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
00104     class array_allocator : public array_allocator_base<_Tp>
00105     {
00106     public:
00107       typedef size_t        size_type;
00108       typedef ptrdiff_t     difference_type;
00109       typedef _Tp*          pointer;
00110       typedef const _Tp*    const_pointer;
00111       typedef _Tp&          reference;
00112       typedef const _Tp&    const_reference;
00113       typedef _Tp           value_type;
00114       typedef _Array        array_type;
00115 
00116     private:
00117       array_type*   _M_array;
00118       size_type     _M_used;
00119 
00120     public:
00121      template<typename _Tp1, typename _Array1 = _Array>
00122         struct rebind
00123         { typedef array_allocator<_Tp1, _Array1> other; };
00124 
00125       array_allocator(array_type* __array = 0) _GLIBCXX_USE_NOEXCEPT 
00126       : _M_array(__array), _M_used(size_type()) { }
00127 
00128       array_allocator(const array_allocator& __o) _GLIBCXX_USE_NOEXCEPT 
00129       : _M_array(__o._M_array), _M_used(__o._M_used) { }
00130 
00131       template<typename _Tp1, typename _Array1>
00132         array_allocator(const array_allocator<_Tp1, _Array1>&)
00133     _GLIBCXX_USE_NOEXCEPT
00134     : _M_array(0), _M_used(size_type()) { }
00135 
00136       ~array_allocator() _GLIBCXX_USE_NOEXCEPT { }
00137 
00138       pointer
00139       allocate(size_type __n, const void* = 0)
00140       {
00141     if (_M_array == 0 || _M_used + __n > _M_array->size())
00142       std::__throw_bad_alloc();
00143     pointer __ret = _M_array->begin() + _M_used;
00144     _M_used += __n;
00145     return __ret;
00146       }
00147     };
00148 
00149   template<typename _Tp, typename _Array>
00150     inline bool
00151     operator==(const array_allocator<_Tp, _Array>&,
00152            const array_allocator<_Tp, _Array>&)
00153     { return true; }
00154   
00155   template<typename _Tp, typename _Array>
00156     inline bool
00157     operator!=(const array_allocator<_Tp, _Array>&, 
00158            const array_allocator<_Tp, _Array>&)
00159     { return false; }
00160 
00161 _GLIBCXX_END_NAMESPACE_VERSION
00162 } // namespace
00163 
00164 #endif