pointer.h

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/**
 * Pointer - A safer way to use pointers
 *
 * @author	Jonathan Roewen
 */
#ifndef POINTER_H
#define POINTER_H

using namespace std;	//	Otherwise this becomes a nightmare later if "Pointer.h" included in wrong order!

template <class T>
class Pointer
{
protected:
	class Holder
	{
	public:
		T *datum;
		unsigned count;
		
		Holder(T *t) : datum(t), count(1) {
		}
		~Holder() {
			delete datum;
		}
	};
	
	Holder *value;
	
	//	I'm just curious .. how does this cope with NULL?
	void unbind() {
		if (--value->count == 0) {
			delete value;
		}
	}
	
	void bind(const Pointer<T> &rhs) {
		if (rhs.value != value) {
			unbind();
			value = rhs.value;
			value->count++;
		}
	}
	
	void bind(T *t) {
		if (value->datum != t) {
			unbind();
			value = new Holder(t);
		}
	}
public:
	explicit Pointer(T *t = NULL) : value(new Holder(t)) {
	}
	Pointer(const Pointer<T> &rhs) : value(rhs.value) {
		value->count++;
	}
	~Pointer() {
		unbind();
	}
	
	Pointer<T> &operator=(const Pointer<T> &rhs) {
		//	Keep getting *bus error* for value->datum
	//	if (value->datum != NULL) {
			bind(rhs);
	//	} else {
	//		value = rhs.value;
	//	}
		return *this;
	}
	
	Pointer<T> &operator=(T *t) {
	//	if (t != NULL) {
			bind(t);
	//	} else {
	//		value = new Holder(t);
	//	}
		return *this;
	}
	
	T *operator->() {
		return value->datum;
	}
	
	T &operator*() {
		return *(value->datum);
	}
	
	const T *operator->() const {
		return value->datum;
	}
	
	const T &operator*() const {
		return *(value->datum);
	}
	
	bool operator==(const Pointer<T> &rhs) const {
		return (value->datum) == (rhs.value->datum);
	}
	
	bool operator!=(const Pointer<T> &rhs) const {
		return (value->datum) != (rhs.value->datum);
	}
	
	bool operator==(T *t) const {
		return (value->datum) == t;
	}
	
	bool operator!=(T *t) const {
		return (value->datum) != t;
	}
};

#endif	//	POINTER_H