gtkradiant/libs/generic/reference.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_REFERENCE_H)
#define INCLUDED_GENERIC_REFERENCE_H

/// \file
/// \brief Wrappers to allow storing objects in templated containers using 'reference' semantics. 

/// \brief A reference to a mutable object.
/// Has 'reference' semantics, except for \c 'operator==' and \c 'operator.'.
/// \param Type The type of the referenced object.
template<typename Type>
class Reference
{ 
  Type* m_contained;
public:
  explicit Reference(Type& contained) : m_contained(&contained)
  {
  }
  Type& operator*() const
  {
    return *m_contained;
  }
  Type* operator->() const
  {
    return m_contained;
  }
  operator Type&() const
  {
    return *m_contained;
  }
  Type& get() const
  {
    return *m_contained;
  }
  Type* get_pointer() const
  {
    return m_contained;
  }
};

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

/// \brief construct a reference to a mutable object.
template<typename Type>
inline Reference<Type> makeReference(Type& value)
{
  return Reference<Type>(value);
}

/// \brief A reference to a non-mutable object.
/// Has 'reference' semantics, except for \c 'operator==' and \c 'operator.'.
/// \param Type The type of the referenced object.
template<typename Type>
class ConstReference
{
  const Type* m_contained;
public:
  explicit ConstReference(const Type& contained) : m_contained(&contained)
  {
  }
  const Type& operator*() const
  {
    return *m_contained;
  }
  const Type* operator->() const
  {
    return m_contained;
  }
  operator const Type&() const
  {
    return *m_contained;
  }
  const Type& get() const
  {
    return *m_contained;
  }
  const Type* get_pointer() const
  {
    return m_contained;
  }
};

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

/// \brief construct a reference to a non-mutable object.
template<typename Type>
inline ConstReference<Type> makeReference(const Type& value)
{
  return ConstReference<Type>(value);
}


#endif