--- /dev/null
+// <extptr_allocator.h> -*- C++ -*-
+
+// Copyright (C) 2008 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this library; see the file COPYING. If not, write to
+// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+// Boston, MA 02110-1301, USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction. Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License. This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+/**
+ * @file ext/extptr_allocator.h
+ * @author Bob Walters
+ *
+ * An example allocator which uses an alternative pointer type from
+ * bits/pointer.h. Supports test cases which confirm container support
+ * for alternative pointers.
+ */
+
+#ifndef _EXTPTR_ALLOCATOR_H
+#define _EXTPTR_ALLOCATOR_H 1
+
+#include <memory>
+#include <limits>
+#include <ext/pointer.h>
+
+using __gnu_cxx::_Pointer_adapter;
+using __gnu_cxx::_Relative_pointer_impl;
+
+_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
+
+ // forward declaration
+ template<typename _Tp>
+ class _ExtPtr_allocator;
+
+ // _ExtPtr_allocator<void> specialization.
+ template<>
+ class _ExtPtr_allocator<void>
+ {
+ public:
+ typedef size_t size_type;
+ typedef ptrdiff_t difference_type;
+ typedef void value_type;
+
+ // Note the non-standard pointer types
+ typedef _Pointer_adapter<_Relative_pointer_impl<void> > pointer;
+ typedef _Pointer_adapter<_Relative_pointer_impl<const void> >
+ const_pointer;
+
+ template<typename _Up>
+ struct rebind
+ { typedef _ExtPtr_allocator<_Up> other; };
+ };
+
+ /**
+ * @brief An example allocator which uses a non-standard pointer type.
+ *
+ * This allocator specifies that containers use a 'relative pointer' as it's
+ * pointer type. (See bits/pointer.h) Memory allocation in this example
+ * is still performed using std::allocator.
+ */
+ template<typename _Tp>
+ class _ExtPtr_allocator
+ {
+ public:
+ typedef size_t size_type;
+ typedef ptrdiff_t difference_type;
+
+ // Note the non-standard pointer types.
+ typedef _Pointer_adapter<_Relative_pointer_impl<_Tp> > pointer;
+ typedef _Pointer_adapter<_Relative_pointer_impl<const _Tp> > const_pointer;
+
+ typedef _Tp& reference;
+ typedef const _Tp& const_reference;
+ typedef _Tp value_type;
+
+ template<typename _Up>
+ struct rebind
+ { typedef _ExtPtr_allocator<_Up> other; };
+
+ _ExtPtr_allocator() throw()
+ : _M_real_alloc() { }
+
+ _ExtPtr_allocator(const _ExtPtr_allocator &__rarg) throw()
+ : _M_real_alloc(__rarg._M_real_alloc) { }
+
+ template<class _Up>
+ _ExtPtr_allocator(const _ExtPtr_allocator<_Up>& __rarg) throw()
+ : _M_real_alloc(__rarg._M_getUnderlyingImp()) { }
+
+ ~_ExtPtr_allocator() throw()
+ { }
+
+ pointer address(reference __x) const
+ { return &__x; }
+
+ const_pointer address(const_reference __x) const
+ { return &__x; }
+
+ pointer allocate(size_type __n, void* __hint = 0)
+ { return _M_real_alloc.allocate(__n,__hint); }
+
+ void deallocate(pointer __p, size_type __n)
+ { _M_real_alloc.deallocate(__p.get(), __n); }
+
+ size_type max_size() const throw()
+ { return std::numeric_limits<size_type>::max() / sizeof(_Tp); }
+
+ void construct(pointer __p, const _Tp& __val)
+ { ::new(__p.get()) _Tp(__val); }
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+ template<typename... _Args>
+ void
+ construct(pointer __p, _Args&&... __args)
+ { ::new(__p.get()) _Tp(std::forward<_Args>(__args)...); }
+#endif
+
+ void destroy(pointer __p)
+ { __p->~_Tp(); }
+
+ template<typename _Up>
+ inline bool
+ operator==(const _ExtPtr_allocator<_Up>& __rarg)
+ { return _M_real_alloc == __rarg._M_getUnderlyingImp(); }
+
+ inline bool
+ operator==(const _ExtPtr_allocator& __rarg)
+ { return _M_real_alloc == __rarg._M_real_alloc; }
+
+ template<typename _Up>
+ inline bool
+ operator!=(const _ExtPtr_allocator<_Up>& __rarg)
+ { return _M_real_alloc != __rarg._M_getUnderlyingImp(); }
+
+ inline bool
+ operator!=(const _ExtPtr_allocator& __rarg)
+ { return _M_real_alloc != __rarg._M_real_alloc; }
+
+ template<typename _Up>
+ inline friend void
+ swap(_ExtPtr_allocator<_Up>& __larg, _ExtPtr_allocator<_Up>& __rarg);
+
+ // A method specific to this implementation.
+ const std::allocator<_Tp>&
+ _M_getUnderlyingImp() const
+ { return _M_real_alloc; }
+
+ private:
+ // simlated state data.
+ std::allocator<_Tp> _M_real_alloc;
+ };
+
+ template<typename _Tp>
+ inline void
+ swap(_ExtPtr_allocator<_Tp>& __larg, _ExtPtr_allocator<_Tp>& __rarg)
+ {
+ std::allocator<_Tp> temp( __rarg._M_real_alloc );
+ __rarg._M_real_alloc = __larg._M_real_alloc;
+ __larg._M_real_alloc = temp;
+ }
+
+_GLIBCXX_END_NAMESPACE
+
+#endif /* _EXTPTR_ALLOCATOR_H */