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#ifndef LPC_POINTER_H1103643194_INCLUDE_GUARD_
#define LPC_POINTER_H1103643194_INCLUDE_GUARD_
/* This file is part of indexlib.
* Copyright (C) 2005 Luís Pedro Coelho <[email protected]>
*
* Indexlib is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation and available as file
* GPL_V2 which is distributed along with indexlib.
*
* Indexlib 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 program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of this program with any edition of
* the Qt library by Trolltech AS, Norway (or with modified versions
* of Qt that use the same license as Qt), and distribute linked
* combinations including the two. You must obey the GNU General
* Public License in all respects for all of the code used other than
* Qt. If you modify this file, you may extend this exception to
* your version of the file, but you are not obligated to do so. If
* you do not wish to do so, delete this exception statement from
* your version.
*/
#include <inttypes.h>
#include <iostream>
#include "boost-compat/static_assert.hpp"
#ifdef HAVE_BOOST
#include <boost/type_traits.hpp>
#endif
/**
* \class pointer
*
* Works with \ref thing in providing disk translucency (not transparency, but half-way there).
*
* This is a pointer like object which is really an index into a memory block which must be deferenced
* every time it is accessed. The main advantage of this is that it allows the pointer to remain valid even
* if the base memory block changes place.
*
* Actually, implementation-wise, thing does all this already and this is mainly an adapter.
*/
template <typename Thing >
struct pointer: private Thing {
private:
typedef Thing base_type;
pointer( uint32_t i )
:base_type( i )
{
}
public:
pointer()
:base_type( 0 )
{
}
typedef Thing value_type;
template <typename D>
pointer( const pointer<D>& other )
:base_type( other.cast_to_uint32() )
{
typedef D derived_type;
BOOST_STATIC_ASSERT( (boost::is_convertible<derived_type, value_type>::value ) );
}
uint32_t cast_to_uint32() const {
return this->idx_;
}
static pointer cast_from_uint32( uint32_t d ) {
return d;
}
value_type& operator* () const {
return const_cast<value_type&>( static_cast<const value_type&>( *this ) );
}
value_type* operator -> () const {
return const_cast<value_type*>( static_cast<const value_type*>( this ) );
}
bool operator!() const {
return !this->idx_;
}
operator const volatile void*() const {
return this->idx_ ? this : 0;
}
void* raw_pointer() { return base_type::base(); }
private:
};
template <typename T>
std::ostream& operator << ( std::ostream& out, const pointer<T>& p ) {
return out << p.cast_to_uint32();
}
#endif /* LPC_POINTER_H1103643194_INCLUDE_GUARD_ */
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