vmap/libs/generic/referencecounted.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_GENERIC_REFERENCECOUNTED_H )
#define INCLUDED_GENERIC_REFERENCECOUNTED_H

/// \file
/// \brief 'smart' pointers and references.

#include <algorithm>

template<typename Type>
class IncRefDecRefCounter
{
public:
void increment( Type& value ){
	value.IncRef();
}
void decrement( Type& value ){
	value.DecRef();
}
};

/// \brief A smart-pointer that uses a counter stored in the object pointed-to.
template<typename Type, typename Counter = IncRefDecRefCounter<Type> >
class SmartPointer : public Counter
{
Type* m_value;
public:

SmartPointer( const SmartPointer& other )
	: m_value( other.m_value ){
	Counter::increment( *m_value );
}
explicit SmartPointer( Type* value )
	: m_value( value ){
	Counter::increment( *m_value );
}
~SmartPointer(){
	Counter::decrement( *m_value );
}
SmartPointer& operator=( const SmartPointer& other ){
	SmartPointer temp( other );
	temp.swap( *this );
	return *this;
}
SmartPointer& operator=( Type* value ){
	SmartPointer temp( value );
	temp.swap( *this );
	return *this;
}
void swap( SmartPointer& other ){
	std::swap( m_value, other.m_value );
}

operator Type*() const
{
	return m_value;
}
Type& operator*() const {
	return *m_value;
}
Type* operator->() const {
	return m_value;
}
Type* get() const {
	return m_value;
}
};

template<typename Type>
inline bool operator<( const SmartPointer<Type>& self, const SmartPointer<Type>& other ){
	return self.get() < other.get();
}
template<typename Type>
inline bool operator==( const SmartPointer<Type>& self, const SmartPointer<Type>& other ){
	return self.get() == other.get();
}
template<typename Type>
inline bool operator!=( const SmartPointer<Type>& self, const SmartPointer<Type>& other ){
	return !::operator==( self, other );
}

namespace std
{
/// \brief Swaps the values of \p self and \p other.
/// Overloads std::swap().
template<typename Type>
inline void swap( SmartPointer<Type>& self, SmartPointer<Type>& other ){
	self.swap( other );
}
}


/// \brief A smart-reference that uses a counter stored in the object pointed-to.
template<typename Type, typename Counter = IncRefDecRefCounter<Type> >
class SmartReference : public Counter
{
Type* m_value;
public:

SmartReference( const SmartReference& other )
	: m_value( other.m_value ){
	Counter::increment( *m_value );
}
explicit SmartReference( Type& value )
	: m_value( &value ){
	Counter::increment( *m_value );
}
~SmartReference(){
	Counter::decrement( *m_value );
}
SmartReference& operator=( const SmartReference& other ){
	SmartReference temp( other );
	temp.swap( *this );
	return *this;
}
SmartReference& operator=( Type& value ){
	SmartReference temp( value );
	temp.swap( *this );
	return *this;
}
void swap( SmartReference& other ){
	std::swap( m_value, other.m_value );
}

operator Type&() const
{
	return *m_value;
}
Type& get() const {
	return *m_value;
}
Type* get_pointer() const {
	return m_value;
}
};

template<typename Type>
inline bool operator<( const SmartReference<Type>& self, const SmartReference<Type>& other ){
	return self.get() < other.get();
}
template<typename Type>
inline bool operator==( const SmartReference<Type>& self, const SmartReference<Type>& other ){
	return self.get() == other.get();
}
template<typename Type>
inline bool operator!=( const SmartReference<Type>& self, const SmartReference<Type>& other ){
	return !::operator==( self, other );
}

namespace std
{
/// \brief Swaps the values of \p self and \p other.
/// Overloads std::swap().
template<typename Type>
inline void swap( SmartReference<Type>& self, SmartReference<Type>& other ){
	self.swap( other );
}
}

#endif