#ifndef OSG_REFERENCED
#define OSG_REFERENCED 1

#include <osg/Export>

namespace osg {

/** Convience functor for unreferencing objects.*/
template<class T>
struct UnrefOp
{
    void operator () (T* node) { node->unref(); }
};

/** Smart pointer for handling referenced counted objects.*/
template<class T>
class ref_ptr
{

    public:
        ref_ptr() :_ptr(0L) {}
        ref_ptr(T* t):_ptr(t)              { if (_ptr) _ptr->ref(); }
        ref_ptr(const ref_ptr& rp):_ptr(rp._ptr)  { if (_ptr) _ptr->ref(); }
        ~ref_ptr()                           { if (_ptr) _ptr->unref(); }

        ref_ptr& operator = (const ref_ptr& rp)
        {
            if (_ptr==rp._ptr) return *this;
            if (_ptr) _ptr->unref();
            _ptr = rp._ptr;
            if (_ptr) _ptr->ref();
            return *this;
        }

        ref_ptr& operator = (T* ptr)
        {
            if (_ptr==ptr) return *this;
            if (_ptr) _ptr->unref();
            _ptr = ptr;
            if (_ptr) _ptr->ref();
            return *this;
        }

        bool operator == (const ref_ptr& rp) const
        {
            return (_ptr==rp._ptr);
        }

        bool operator == (const T* ptr) const
        {
            return (_ptr==ptr);
        }

        bool operator != (const ref_ptr& rp) const
        {
            return (_ptr!=rp._ptr);
        }

        bool operator != (const T* ptr) const
        {
            return (_ptr!=ptr);
        }

        T& operator*() const    { return *_ptr; }
        T* operator->() const   { return _ptr; }
	bool operator!() const	{ return _ptr==0L; }
	bool valid() const	{ return _ptr!=0L; }

        T* get() const { return _ptr; }

    private:
        T* _ptr;
};

/** Base class from providing referencing counted objects.*/
class Referenced
{

    public:
        Referenced() { _refCount=0; }
        Referenced(Referenced&) { _refCount=0; }

        Referenced& operator = (Referenced&) { return *this; }

        /** increment the reference count by one, indicating that 
            this object has another pointer which is referencing it.*/
        void ref() { ++_refCount; }
        /** decrement the reference count by one, indicating that 
            a pointer to this object is referencing it.  If the
            refence count goes to zero, it is assumed that this object
            is nolonger referenced and is automatically deleted.*/
        void unref() { --_refCount; if (_refCount<=0) delete this; }
        /** return the number pointers currently referencing this object. */
        int referenceCount() { return _refCount; }

    protected:
        virtual ~Referenced() {};
        int _refCount;
};

};

#endif