// Programmed by Anthony Barbachan
// Programmed in Turbo C++ 3.0
// Note: This is the header file for the object library (OBJECT??.LIB)
// Purpose: To provide components for data structures.

// Version 1.00
// Last Modified On 7/9/95

#ifndef __OBJECT_HPP__
#define __OBJECT_HPP__

#include <stddef.h>

//////////////////////////////////////////////////////////////////////////////

// This class provides a base for many types of data structures

class ObjectBase
{
	protected:
		ObjectBase* next;
		ObjectBase* prev;
	public:
		ObjectBase() { prev = next = NULL; }
		ObjectBase(ObjectBase* n) { next = n; prev = NULL; }
		ObjectBase(ObjectBase* n, ObjectBase* p) { next = n; prev = p; }
		virtual ~ObjectBase() {}
		ObjectBase* LinkNext(ObjectBase* n);
		ObjectBase* LinkPrevious(ObjectBase* p);
		ObjectBase* UnLinkNext() { return LinkNext(NULL); }
		ObjectBase* UnLinkPrevious() { return LinkPrevious(NULL); }
		ObjectBase* AccessNext() { return next; }
		ObjectBase* AccessPrevious() { return prev; }
		int NoNext() { return next == NULL; }
		int HasNext() { return next != NULL; }
		int NoPrevious() { return prev == NULL; }
		int HasPrevious() { return prev != NULL; }
		int IsLinked() { return HasNext() || HasPrevious(); }
		int NotLinked() { return NoNext() || NoPrevious(); }
};

///////////////////////////////////////***************************************

//////////////////////////////////////////////////////////////////////////////

// This class provides a means by which object can be defined in a method
// which allows its use in ObjectBase data structures.

template <class ObjectType>
class ObjectOf	:	public ObjectBase, public ObjectType
{
	public:
		ObjectOf() : ObjectBase(), ObjectType() {}
		ObjectOf(ObjectOf* n) : ObjectBase(n), ObjectType() {}
		ObjectOf(ObjectOf* n, ObjectOf* p) : ObjectBase(n,p),ObjectType() {}
		virtual ~ObjectOf() {}
		ObjectOf* LinkNext(ObjectOf* n)
	{ return (ObjectOf<ObjectType> *) ObjectBase::LinkNext(n); }
		ObjectOf* LinkPrevious(ObjectOf* p)
	{ return (ObjectOf<ObjectType> *) ObjectBase::LinkPrevious(p); }
		ObjectOf* UnLinkNext()
	{ return (ObjectOf<ObjectType> *) ObjectBase::UnLinkNext(); }
		ObjectOf* UnLinkPrevious()
	{ return (ObjectOf<ObjectType> *) ObjectBase::UnLinkPrevious(); }
		ObjectOf* AccessNext()
	{ return (ObjectOf<ObjectType> *) ObjectBase::AccessNext(); }
		ObjectOf* AccessPrevious()
	{ return (ObjectOf<ObjectType> *) ObjectBase::AccessPrevious(); }
		ObjectType& AccessObject() { return *this; }
		ObjectType& operator * () { return *this; }
};

///////////////////////////////////////***************************************

//////////////////////////////////////////////////////////////////////////////

// This class provides a means by which defined object can be
// used in ObjectBase data structures.

template <class ObjectType>
class ObjectHolder	:	public ObjectBase
{
	protected:
		ObjectType* obj;
	public:
		ObjectHolder() : ObjectBase() { obj = NULL; }
		ObjectHolder(ObjectType* o) : ObjectBase() { obj = o; }
		ObjectHolder(ObjectHolder* n) : ObjectBase(n) { obj = NULL; }
		ObjectHolder(ObjectType* o, ObjectHolder* n):ObjectBase(n){obj = o;}
		ObjectHolder(ObjectType* o, ObjectHolder* p, ObjectHolder* n)
								: ObjectBase(n, p) { obj = o; }
		virtual ~ObjectHolder() { if(obj != NULL) delete obj; }
		ObjectType* LinkObject(ObjectType* o);
		ObjectType* UnLinkObject() { return LinkObject(NULL); }
		ObjectHolder* LinkNext(ObjectHolder* n)
	{ return (ObjectHolder<ObjectType> *) ObjectBase::LinkNext(n); }
		ObjectHolder* LinkPrevious(ObjectHolder* p)
	{ return (ObjectHolder<ObjectType> *) ObjectBase::LinkPrevious(p); }
		ObjectHolder* UnLinkNext()
	{ return (ObjectHolder<ObjectType> *) ObjectBase::UnLinkNext(); }
		ObjectHolder* UnLinkPrevious()
	{ return (ObjectHolder<ObjectType> *) ObjectBase::UnLinkPrevious(); }
		ObjectHolder* AccessNext()
	{ return (ObjectHolder<ObjectType> *) ObjectBase::AccessNext(); }
		ObjectHolder* AccessPrevious()
	{ return (ObjectHolder<ObjectType> *) ObjectBase::AccessPrevious(); }
		int NoObject() { return obj == NULL; }
		int HasObject() { return obj != NULL; }
		ObjectType* AccessObject() { return obj; }
		operator ObjectType * () { return obj; }
};

///////////////////////////////////////***************************************

//////////////////////////////////////////////////////////////////////////////

// This class provides a means by which any data type can be defined in a
// method which allows its use in ObjectBase data structures.

template <class ObjectType>
class ObjectContainer	:	public ObjectBase
{
	protected:
		ObjectType obj;
	public:
		ObjectContainer() : ObjectBase() {}
		ObjectContainer(ObjectContainer* n) : ObjectBase(n) {}
		ObjectContainer(ObjectContainer* n, ObjectContainer* p)
					: ObjectBase(n, p) {}
		virtual ~ObjectContainer() {}
		ObjectContainer* LinkNext(ObjectContainer* n)
	{ return (ObjectContainer<ObjectType> *) ObjectBase::LinkNext(n); }
		ObjectContainer* LinkPrevious(ObjectContainer* p)
	{ return (ObjectContainer<ObjectType> *) ObjectBase::LinkPrevious(p); }
		ObjectContainer* UnLinkNext()
	{ return (ObjectContainer<ObjectType> *) ObjectBase::UnLinkNext(); }
		ObjectContainer* UnLinkPrevious()
	{ return (ObjectContainer<ObjectType> *) ObjectBase::UnLinkPrevious(); }
		ObjectContainer* AccessNext()
	{ return (ObjectContainer<ObjectType> *) ObjectBase::AccessNext(); }
		ObjectContainer* AccessPrevious()
	{ return (ObjectContainer<ObjectType> *) ObjectBase::AccessPrevious(); }
		ObjectType& AccessObject() { return obj; }
		ObjectType& operator * () { return obj; }
		operator ObjectType & () { return obj; }
};

///////////////////////////////////////***************************************
///////////////////////////////////////***************************************

// This function returns the value of obj and set obj to o

template <class ObjectType>
ObjectType* ObjectHolder<ObjectType>::LinkObject(ObjectType* o)
{
	ObjectType* old = obj;			// Save old value of obj
	obj = o;						// Save value of o in obj
	return old;					// Return old value of obj
}

///////////////////////////////////////***************************************

#endif