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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 <luis@luispedro.org>
+ *
+ * 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_ */