//-----------------------------------------------------------------------------+
// Copyright (C), 1998-2007, Beijing Tangent Software Co. Ltd.
// = FileName	:   TPGeGDList.h
// = Version	:   ver2.0
// = Author		:   xlc
// = CreateDate	:   2002-09-09
// = Description:   类的声明 双向递归链

// = Maintainers: 
//                  
//-----------------------------------------------------------------------------+
#ifndef _TPGEGDLIST_H_
#define _TPGEGDLIST_H_

#ifndef _TPGEGLIST_H_
#include "TPGeGList.h"
#endif

template<class T> class TPGeGDList : public TPGeGList<T>
{
public:
	TPGeGDList();

	//pList!=NULL!!!
	virtual void CNNext(TPGeGDList*pList);
	
	virtual void DCNNext();

	//释放所有前面结点，本结点成为起始结点
	void ReleaseAllPre();

	TPGeGDList<T>*Next() const;

	TPGeGDList<T>*Pre() const;
	
	TPGeGDList<T>* GetTail() const;
	
	//如果是环路GetTail与GetHead结果相同
	TPGeGDList<T>* GetHead() const;

	TPGeGDList<T>* GetAt(long i) const;

	const T& GetData(long i) const;
	
	void DCNPre();

	void SetPre(TPGeGDList<T>* pList) const;

	//安全转接,自动断开所有原相关链接,pList!=NULL!!!
	void CNPre(TPGeGDList*pList);

	TPGeGDList<T>* FetchNext(long num = 1);

	//返回新链首,如果本结点非链首，将在本结点处形成分叉!如果是环路将保持环路
	TPGeGDList<T>* Reverse();

protected:

	TPGeGDList* pre;
};

template<class T>
TPGeGDList<T>::TPGeGDList()	: pre(NULL)
{

}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::Next() const
{
	return (TPGeGDList<T>*)this->next;
}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::Pre() const
{
	return pre;
}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::GetTail() const
{
	return (TPGeGDList<T>*)(TPGeGList<T>::GetTail());
}

template<class T>
const T& TPGeGDList<T>::GetData(long i) const
{
	return GetAt(i)->GetData();
}

template<class T>
void TPGeGDList<T>::SetPre(TPGeGDList<T>* pList) const
{//一般不使用!
	pre = pList;
}

template<class T>
void TPGeGDList<T>::DCNNext()
{
	if (this->next != NULL)
	{
		this->next->SetPre(NULL);
		this->next = NULL;
	}
}

template<class T>
void TPGeGDList<T>::DCNPre()
{
	if(pre != NULL)
	{
		pre->SetNext(NULL);
		pre = NULL;
	}
}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::FetchNext(long num/* = 1*/)
{
	return (TPGeGDList<T>*)(TPGeGList<T>::FetchNext(num));
}

template<class T>
void TPGeGDList<T>::CNNext(TPGeGDList*pList)
{
	DCNNext();
	pList->DCNPre();
	this->SetNext(pList);
	pList->SetPre(this);
}

template<class T>
void TPGeGDList<T>::CNPre(TPGeGDList*pList)
{
	DCNPre();
	pList->DCNNext();
	SetPre(pList);
	pList->SetNext(this);
}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::GetHead() const
{
	for(const TPGeGDList<T>*pCur = this; pCur->Pre() != NULL && pCur->Pre() != this; pCur = pCur->Pre());
	return (TPGeGDList<T>*)this->pCur;
}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::GetAt(long i) const
{
	if(i >= 0)
	{
		return (TPGeGDList<T>*)(TPGeGList<T>::GetAt(i));
	}
	else
	{
		long count = 1;
		for(TPGeGDList<T>*pCur = Pre(); count< -i && pCur != NULL; count++, pCur = pCur->Pre());
		return this->pCur;
	}
}

template<class T>
void TPGeGDList<T>::ReleaseAllPre()
{
	TPGeGDList<T>* pHead = GetHead();
	DCNPre();
	delete pHead;
}

template<class T>
TPGeGDList<T>* TPGeGDList<T>::Reverse()
{
	TPGeGDList<T> *pPre = this,*pCur = Next();
	while(pCur != NULL && pCur != this)
	{
		TPGeGDList<T>* temp = pCur->Next();
		pCur->SetNext(pPre);
		pPre->SetPre(pCur);
		pPre = pCur;
		pCur = temp;
	}
	if(pCur == NULL)
	{
		this->SetNext(NULL);
		pPre->SetPre(NULL);
		return pPre;
	}
	else
	{
		this->SetNext(pPre);
		pPre->SetPre(this);
		return this;
	}	
}

#endif