vmap/libs/typesystem.h

/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant 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 of the License, or
   (at your option) any later version.

   GtkRadiant 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 GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined( INCLUDED_TYPESYSTEM_H )
#define INCLUDED_TYPESYSTEM_H


#include <list>
#include <vector>
#include "generic/callback.h"
#include "generic/static.h"

class InitialiserList
{
typedef std::list<Callback<void ()> > Initialisers;
Initialisers m_initialisers;
mutable bool m_initialised;
public:
InitialiserList() : m_initialised( false ){
}
void addInitialiser( const Callback<void()>& callback ){
	m_initialisers.push_back( callback );
}
void initialise() const {
	if ( !m_initialised ) {
		m_initialised = true;

		for ( Initialisers::const_iterator i = m_initialisers.begin(); i != m_initialisers.end(); ++i )
		{
			( *i )( );
		}
	}
}
};

//--Type System-------------------

class TypeSystemInitialiser : public InitialiserList
{
};

typedef SmartStatic<TypeSystemInitialiser> StaticTypeSystemInitialiser;

class TypeSystemRef : public StaticTypeSystemInitialiser
{
public:
TypeSystemRef(){
	StaticTypeSystemInitialiser::instance().initialise();
}
};



typedef std::size_t TypeId;
typedef void*( *TypeCast )( void* );

template<std::size_t SIZE>
class TypeCastTable
{
TypeCast m_casts[SIZE];
public:
TypeCastTable(){
	std::uninitialized_fill( m_casts, m_casts + SIZE, TypeCast( 0 ) );
}
void install( TypeId typeId, TypeCast typeCast ){
	m_casts[typeId] = typeCast;
}
void* cast( TypeId typeId, void* p ){
	TypeCast typeCast = m_casts[typeId];
	if ( typeCast != 0 ) {
		return typeCast( p );
	}
	return 0;
}
};

template<typename Type, typename Cast>
class CastInstaller
{
public:
static void install( TypeCastTable<Type::SIZE>& table ){
	table.install( Type::getTypeId(), Cast::cast );
}
};

template<typename Type>
class IdentityCast
{
public:
static void* cast( void* p ){
	return p;
}
};

template<typename Type, typename Base>
class StaticCast
{
public:
static void* cast( void* p ){
	return static_cast<Base*>( reinterpret_cast<Type*>( p ) );
}
};

template<typename Type>
class NullType
{
};

template<typename Type, typename Contained>
class ContainedCast
{
public:
static void* cast( void* p ){
	return &reinterpret_cast<Type*>( p )->get( NullType<Contained>() );
}
};


#endif