#ifndef XPARAM_ICONV_H
#define XPARAM_ICONV_H

/*	Copyright (C) 2001,2002,2003 Ronnie Maor and Michael Brand
 * 
 * This program 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 program 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * As a special exception, the copyright holders give permission
 * for additional uses of the text contained in its release of XPARAM.
 *
 * The exception is that, if you link the XPARAM library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the XPARAM library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * If you write modifications of your own for XPARAM, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  
 */

/*
 * Provides IConv - an interface for dynamically converting pointers
 * between ancestors and descendants.
 */

#include <typeinfo>
#include "xp_config.h"
#include "xp_handle.h"
#include "xp_value.h"

namespace xParam_internal {

	class IConv {
		public:
			virtual ~IConv() {}

			virtual const std::type_info& ancestor() const = 0;
			virtual const std::type_info& descendant() const = 0;

			// whether this corresponds to a direct inheritance,
			// or goes through intermediate classes.
			virtual bool is_atomic() const = 0;

			// 'val' must satisfy 
			//      val->static_type_info() == ancestor()
			// the return value 'ret' will satisfy 
			//      ret->static_type_info() == descendant()
			virtual Handle<Value> downcast(const Value& val) const = 0;

			// 'obj' must satisfy 
			//       reinterpret_cast<B*>(obj) is a legal B* (where typeid(B)==descendant())
			// the return value 'ret' will statify
			//       reinterpret_cast<A*>(obj) is a legal A* (where typeid(A)==ancestor())
			virtual void* upcast(void *obj) const = 0;
	};

} // namespace xParam_internal

#endif // XPARAM_ICONV_H
