libstdc++
array_allocator.h
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00001 // array allocator -*- C++ -*-
00002 
00003 // Copyright (C) 2004-2013 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /** @file ext/array_allocator.h
00026  *  This file is a GNU extension to the Standard C++ Library.
00027  */
00028 
00029 #ifndef _ARRAY_ALLOCATOR_H
00030 #define _ARRAY_ALLOCATOR_H 1
00031 
00032 #include <bits/c++config.h>
00033 #include <new>
00034 #include <bits/functexcept.h>
00035 #include <tr1/array>
00036 #include <bits/move.h>
00037 #if __cplusplus >= 201103L
00038 #include <type_traits>
00039 #endif
00040 
00041 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
00042 {
00043 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00044 
00045  using std::size_t;
00046  using std::ptrdiff_t;
00047 
00048   /// Base class.
00049  template<typename _Tp>
00050     class array_allocator_base
00051     {
00052     public:
00053       typedef size_t        size_type;
00054       typedef ptrdiff_t     difference_type;
00055       typedef _Tp*          pointer;
00056       typedef const _Tp*    const_pointer;
00057       typedef _Tp&          reference;
00058       typedef const _Tp&    const_reference;
00059       typedef _Tp           value_type;
00060 
00061       pointer
00062       address(reference __x) const _GLIBCXX_NOEXCEPT
00063       { return std::__addressof(__x); }
00064 
00065       const_pointer
00066       address(const_reference __x) const _GLIBCXX_NOEXCEPT
00067       { return std::__addressof(__x); }
00068 
00069       void
00070       deallocate(pointer, size_type)
00071       { 
00072     // Does nothing.
00073       }
00074 
00075       size_type
00076       max_size() const _GLIBCXX_USE_NOEXCEPT 
00077       { return size_t(-1) / sizeof(_Tp); }
00078 
00079 #if __cplusplus >= 201103L
00080       template<typename _Up, typename... _Args>
00081         void
00082         construct(_Up* __p, _Args&&... __args)
00083     { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
00084 
00085       template<typename _Up>
00086         void 
00087         destroy(_Up* __p) { __p->~_Up(); }
00088 #else
00089       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00090       // 402. wrong new expression in [some_] allocator::construct
00091       void 
00092       construct(pointer __p, const _Tp& __val) 
00093       { ::new((void *)__p) value_type(__val); }
00094 
00095       void 
00096       destroy(pointer __p) { __p->~_Tp(); }
00097 #endif
00098     };  
00099 
00100   /**
00101    *  @brief  An allocator that uses previously allocated memory.
00102    *  This memory can be externally, globally, or otherwise allocated.
00103    *  @ingroup allocators
00104    */
00105   template<typename _Tp, typename _Array = std::tr1::array<_Tp, 1> >
00106     class array_allocator : public array_allocator_base<_Tp>
00107     {
00108     public:
00109       typedef size_t        size_type;
00110       typedef ptrdiff_t     difference_type;
00111       typedef _Tp*          pointer;
00112       typedef const _Tp*    const_pointer;
00113       typedef _Tp&          reference;
00114       typedef const _Tp&    const_reference;
00115       typedef _Tp           value_type;
00116       typedef _Array        array_type;
00117 
00118 #if __cplusplus >= 201103L
00119       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00120       // 2103. std::allocator propagate_on_container_move_assignment
00121       typedef std::true_type propagate_on_container_move_assignment;
00122 #endif
00123 
00124     private:
00125       array_type*   _M_array;
00126       size_type     _M_used;
00127 
00128     public:
00129      template<typename _Tp1, typename _Array1 = _Array>
00130         struct rebind
00131         { typedef array_allocator<_Tp1, _Array1> other; };
00132 
00133       array_allocator(array_type* __array = 0) _GLIBCXX_USE_NOEXCEPT 
00134       : _M_array(__array), _M_used(size_type()) { }
00135 
00136       array_allocator(const array_allocator& __o) _GLIBCXX_USE_NOEXCEPT 
00137       : _M_array(__o._M_array), _M_used(__o._M_used) { }
00138 
00139       template<typename _Tp1, typename _Array1>
00140         array_allocator(const array_allocator<_Tp1, _Array1>&)
00141     _GLIBCXX_USE_NOEXCEPT
00142     : _M_array(0), _M_used(size_type()) { }
00143 
00144       ~array_allocator() _GLIBCXX_USE_NOEXCEPT { }
00145 
00146       pointer
00147       allocate(size_type __n, const void* = 0)
00148       {
00149     if (_M_array == 0 || _M_used + __n > _M_array->size())
00150       std::__throw_bad_alloc();
00151     pointer __ret = _M_array->begin() + _M_used;
00152     _M_used += __n;
00153     return __ret;
00154       }
00155     };
00156 
00157   template<typename _Tp, typename _Array>
00158     inline bool
00159     operator==(const array_allocator<_Tp, _Array>&,
00160            const array_allocator<_Tp, _Array>&)
00161     { return true; }
00162   
00163   template<typename _Tp, typename _Array>
00164     inline bool
00165     operator!=(const array_allocator<_Tp, _Array>&, 
00166            const array_allocator<_Tp, _Array>&)
00167     { return false; }
00168 
00169 _GLIBCXX_END_NAMESPACE_VERSION
00170 } // namespace
00171 
00172 #endif