citer.h

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/*____________________________________________________________________________
		Copyright (C) 2002 PGP Corporation
        All rights reserved.

        $Id: CIter.h,v 1.2 2002/08/06 20:09:36 dallen Exp $
____________________________________________________________________________*/

#ifndef Included_CIter_h	// [
#define Included_CIter_h

#include "CList.h"

_PGP_BEGIN

// Class CIter

template <typename T> class CIter
{
public:
	CIter(const CList<T> *pItems);

	virtual ~CIter() { }

	PGPUInt32	Count() const {return mPItems->Count();}

	PGPInt32	MaxIndex() const {return static_cast<PGPInt32>(Count() - 1);}
	PGPInt32	Index() const {return mIndex;}
	T *			Current() const {return mCurItem;}

	T *			Move(PGPInt32 relOffset, PGPBoolean fromStart = FALSE);
	PGPInt32	Seek(const T *pSoughtItem) const;
	T *			Next();
	T *			Prev();
	void		Rewind();

private:
	const CList<T>	*mPItems;

	T			*mCurItem;
	PGPInt32	mIndex;

	T *	GoToNewIndex(PGPInt32 newIndex);
};


// Class CIter template member functions

template <typename T> 
CIter<T>::CIter(const CList<T> *pItems) : 
	mPItems(pItems),  mCurItem(NULL), mIndex(-1)
{
	pgpAssertAddrValid(pItems, CList<T>);
}

template <typename T> 
T * 
CIter<T>::Move(PGPInt32 relOffset, PGPBoolean fromStart)
{
	if (fromStart)
		return GoToNewIndex(relOffset);
	else
		return GoToNewIndex(mIndex + relOffset);
}

template <typename T> 
PGPInt32 
CIter<T>::Seek(const T *pSoughtItem) const
{
	pgpAssertAddrValid(pSoughtItem, T);

	T			*pItem	= mPItems->Head();
	PGPInt32	result	= -1;

	for (PGPInt32 i = 0; i <= MaxIndex(); i++)
	{
		if (pItem == pSoughtItem)
		{
			result = i;
			break;
		}

		pItem = mPItems->Next(pItem);
	}

	return result;
}

template <typename T> 
T * 
CIter<T>::Next()
{
	return GoToNewIndex(mIndex + 1);
}

template <typename T> 
T * 
CIter<T>::Prev()
{
	return GoToNewIndex(mIndex - 1);
}

template <typename T> 
void 
CIter<T>::Rewind()
{
	GoToNewIndex(-1);
}

template <typename T> 
T * 
CIter<T>::GoToNewIndex(PGPInt32 newIndex)
{
	if ((newIndex < -1) || (newIndex > MaxIndex()))
		return NULL;

	if (newIndex == -1)
	{
		mCurItem = NULL;
	}
	else if (newIndex == 0)
	{
		mCurItem = mPItems->Head();
	}
	else if (newIndex == MaxIndex())
	{
		mCurItem = mPItems->Tail();
	}
	else
	{
		PGPBoolean	trueIfGoingRight	= (newIndex > mIndex);
		PGPUInt32	diff				= abs(newIndex - mIndex);

		for (PGPUInt32 i = 0; i < diff; i++)
		{
			if (trueIfGoingRight)
				mCurItem = mPItems->Next(mCurItem);
			else
				mCurItem = mPItems->Prev(mCurItem);
		}
	}

	mIndex = newIndex;
	return mCurItem;
}

_PGP_END

#endif	// ] Included_CIter_h