class ItemReference
{
protected:
// The size of the m_QuantumNumber field limits the number
// of quanta that can exist in one file.  If we don't want
// to increase the size of an ItemReference object, then
// we can't increase this number without simultaneously
// lowering the number of items in a block.
	unsigned m_QuantumNumber:20;
	unsigned m_RelativeItemNumber:12;
public:
int	IsReference() { return m_RelativeItemNumber != NoItem; }
int	GetItemNumber() {return m_RelativeItemNumber;}
int	GetQuantumNumber() {return m_QuantumNumber;}
	void SetItemNumber(ArrayIndex p_ItemNumber)
		{
		m_RelativeItemNumber = p_ItemNumber;
		}
	void SetQuantumNumber(QuantumNumber p_QuantumNumber)
		{
		m_QuantumNumber = p_QuantumNumber;
		}
};