177 lines
5.5 KiB
C++
177 lines
5.5 KiB
C++
// <extptr_allocator.h> -*- C++ -*-
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// Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/**
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* @file ext/extptr_allocator.h
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* @author Bob Walters
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*
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* An example allocator which uses an alternative pointer type from
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* bits/pointer.h. Supports test cases which confirm container support
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* for alternative pointers.
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*/
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#ifndef _EXTPTR_ALLOCATOR_H
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#define _EXTPTR_ALLOCATOR_H 1
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#include <memory>
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#include <limits>
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#include <ext/pointer.h>
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_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
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/**
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* @brief An example allocator which uses a non-standard pointer type.
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* @ingroup allocators
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*
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* This allocator specifies that containers use a 'relative pointer' as it's
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* pointer type. (See ext/pointer.h) Memory allocation in this example
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* is still performed using std::allocator.
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*/
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template<typename _Tp>
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class _ExtPtr_allocator
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{
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public:
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typedef std::size_t size_type;
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typedef std::ptrdiff_t difference_type;
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// Note the non-standard pointer types.
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typedef _Pointer_adapter<_Relative_pointer_impl<_Tp> > pointer;
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typedef _Pointer_adapter<_Relative_pointer_impl<const _Tp> >
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const_pointer;
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typedef _Tp& reference;
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typedef const _Tp& const_reference;
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typedef _Tp value_type;
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template<typename _Up>
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struct rebind
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{ typedef _ExtPtr_allocator<_Up> other; };
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_ExtPtr_allocator() throw()
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: _M_real_alloc() { }
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_ExtPtr_allocator(const _ExtPtr_allocator &__rarg) throw()
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: _M_real_alloc(__rarg._M_real_alloc) { }
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template<typename _Up>
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_ExtPtr_allocator(const _ExtPtr_allocator<_Up>& __rarg) throw()
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: _M_real_alloc(__rarg._M_getUnderlyingImp()) { }
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~_ExtPtr_allocator() throw()
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{ }
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pointer address(reference __x) const
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{ return std::__addressof(__x); }
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const_pointer address(const_reference __x) const
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{ return std::__addressof(__x); }
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pointer allocate(size_type __n, void* __hint = 0)
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{ return _M_real_alloc.allocate(__n,__hint); }
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void deallocate(pointer __p, size_type __n)
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{ _M_real_alloc.deallocate(__p.get(), __n); }
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size_type max_size() const throw()
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{ return std::numeric_limits<size_type>::max() / sizeof(_Tp); }
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void construct(pointer __p, const _Tp& __val)
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{ ::new(__p.get()) _Tp(__val); }
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#ifdef __GXX_EXPERIMENTAL_CXX0X__
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template<typename... _Args>
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void
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construct(pointer __p, _Args&&... __args)
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{ ::new(__p.get()) _Tp(std::forward<_Args>(__args)...); }
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#endif
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void destroy(pointer __p)
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{ __p->~_Tp(); }
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template<typename _Up>
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inline bool
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operator==(const _ExtPtr_allocator<_Up>& __rarg)
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{ return _M_real_alloc == __rarg._M_getUnderlyingImp(); }
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inline bool
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operator==(const _ExtPtr_allocator& __rarg)
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{ return _M_real_alloc == __rarg._M_real_alloc; }
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template<typename _Up>
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inline bool
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operator!=(const _ExtPtr_allocator<_Up>& __rarg)
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{ return _M_real_alloc != __rarg._M_getUnderlyingImp(); }
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inline bool
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operator!=(const _ExtPtr_allocator& __rarg)
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{ return _M_real_alloc != __rarg._M_real_alloc; }
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template<typename _Up>
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inline friend void
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swap(_ExtPtr_allocator<_Up>&, _ExtPtr_allocator<_Up>&);
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// A method specific to this implementation.
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const std::allocator<_Tp>&
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_M_getUnderlyingImp() const
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{ return _M_real_alloc; }
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private:
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std::allocator<_Tp> _M_real_alloc;
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};
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// _ExtPtr_allocator<void> specialization.
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template<>
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class _ExtPtr_allocator<void>
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{
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public:
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typedef std::size_t size_type;
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typedef std::ptrdiff_t difference_type;
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typedef void value_type;
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// Note the non-standard pointer types
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typedef _Pointer_adapter<_Relative_pointer_impl<void> > pointer;
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typedef _Pointer_adapter<_Relative_pointer_impl<const void> >
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const_pointer;
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template<typename _Up>
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struct rebind
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{ typedef _ExtPtr_allocator<_Up> other; };
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private:
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std::allocator<void> _M_real_alloc;
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};
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template<typename _Tp>
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inline void
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swap(_ExtPtr_allocator<_Tp>& __larg, _ExtPtr_allocator<_Tp>& __rarg)
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{
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std::allocator<_Tp> __tmp( __rarg._M_real_alloc );
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__rarg._M_real_alloc = __larg._M_real_alloc;
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__larg._M_real_alloc = __tmp;
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}
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_GLIBCXX_END_NAMESPACE
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#endif /* _EXTPTR_ALLOCATOR_H */
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