array.tcc

/*
20050125	ljz     Added 'ReplaceAt()' to the 'Array' class
*/
/****************************************************************************
          Copyright (C) 1995, University of California, Davis

          THIS SOFTWARE IS MADE AVAILABLE, AS IS, AND THE UNIVERSITY
          OF CALIFORNIA DOES NOT MAKE ANY WARRANTY ABOUT THE SOFTWARE, ITS
          PERFORMANCE, ITS MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR
          USE, FREEDOM FROM ANY COMPUTER DISEASES OR ITS CONFORMITY TO ANY
          SPECIFICATION. THE ENTIRE RISK AS TO QUALITY AND PERFORMANCE OF
          THE SOFTWARE IS WITH THE USER.

          Copyright of the software and supporting documentation is
          owned by the University of California, and free access
          is hereby granted as a license to use this software, copy this
          software and prepare derivative works based upon this software.
          However, any distribution of this software source code or
          supporting documentation or derivative works (source code and
          supporting documentation) must include this copyright notice.
****************************************************************************/

/***************************************************************************
 *
 * University of California, Davis
 * UCDMC DICOM Network Transport Libraries
 * Version 0.1 Beta
 *
 * Technical Contact: mhoskin@ucdavis.edu
 *
 ***************************************************************************/

/*
template	<class	DATATYPE>
	Array<DATATYPE>	::	Array ()
	{
	ArraySize = 0;
	first = NULL;
	last = NULL;
	ClearType = 1;
	}
*/

template	<class	DATATYPE>
	Array<DATATYPE>	::	Array (UINT	CT)
	{
	ArraySize = 0;
	first = NULL;
	last = NULL;
	LastAccess = NULL;
	LastAccessNumber = 0;
	ClearType = CT;
	}

template	<class	DATATYPE>
	Array<DATATYPE>	::	~Array()
	{
	if(ClearType == 1)
		{
		while(ArraySize)
			RemoveAt(0);
		}
	}

template	<class	DATATYPE>
DATATYPE	&	Array<DATATYPE>	::	Add(DATATYPE	&Value)
	{

	// record current end-of-chain element

	DataLink<DATATYPE>	*dl = last;

	// chain on new element at tail of chain

	last = new DataLink<DATATYPE>;
	last->Data = Value;

	// set new element's backward pointer to point to former
	// end-of-chain element

	last->prev = dl;

	// set former end-of-chain's next pointer to point to new element

	if(dl)
	{
		dl->next = last;
	}
	else
	{
		// there was previously no "last" element so the one just
		// allocated must be the first

		first = last;
	}

	++ArraySize;
	return ( Value );
	}

template	<class	DATATYPE>
DATATYPE	&	Array<DATATYPE>	::	Get(unsigned int	Index)
	{
	DataLink<DATATYPE>	*dl;
	unsigned	int		rIndex = Index;
	
	if ( Index >= ArraySize )
		{
		//fprintf(stderr, "Returning NULL Data\n");
		//return ( NullData );
		dl = NULL;
		return ( (DATATYPE &) *dl );	// Invoke a seg fault
		}

	if ( LastAccess )
		{
		if ((LastAccessNumber + 1) == Index )
			{
			LastAccess = LastAccess->next;
			++LastAccessNumber;
			return ( LastAccess->Data );
			}
		}

	// locate requested element by following pointer chain
	// decide which is faster -- scan from head or scan from tail

	if(Index < ArraySize / 2)
		{

		// requested element closer to head -- scan forward

		dl = first;
		++Index;
		while(--Index > 0)
			{
			dl = dl->next;
			}
		}
		else
		{

		// requested element closer to tail -- scan backwards

		dl = last;
		Index = (ArraySize - Index);
		while(--Index > 0)
			{
			dl = dl->prev;
			}
		}

	LastAccess = dl;
	LastAccessNumber = rIndex;
	return ( dl->Data );
	}

template	<class	DATATYPE>
DATATYPE	&	Array<DATATYPE>	::	ReplaceAt(DATATYPE	&Value, unsigned int	Index)
	{
	DataLink<DATATYPE>	*dl;
	unsigned	int		rIndex = Index;
	
	if ( Index >= ArraySize )
		{
		//fprintf(stderr, "Returning NULL Data\n");
		//return ( NullData );
		dl = NULL;
		return ( (DATATYPE &) *dl );	// Invoke a seg fault
		}

	if ( LastAccess )
		{
		if ((LastAccessNumber + 1) == Index )
			{
			LastAccess = LastAccess->next;
			++LastAccessNumber;
			LastAccess->Data = Value;
			return ( LastAccess->Data );
			}
		}

	// locate requested element by following pointer chain
	// decide which is faster -- scan from head or scan from tail

	if(Index < ArraySize / 2)
		{

		// requested element closer to head -- scan forward

		dl = first;
		++Index;
		while(--Index > 0)
			{
			dl = dl->next;
			}
		}
		else
		{

		// requested element closer to tail -- scan backwards

		dl = last;
		Index = (ArraySize - Index);
		while(--Index > 0)
			{
			dl = dl->prev;
			}
		}

	LastAccess = dl;
	LastAccessNumber = rIndex;
	dl->Data = Value;
	return ( dl->Data );
	}

template	<class	DATATYPE>
BOOL	Array<DATATYPE>	::	RemoveAt(unsigned int Index)
	{
	DataLink<DATATYPE>	*dl;

	LastAccess = NULL;
	LastAccessNumber = 0;

	if( Index >= ArraySize )
		{
		//fprintf(stderr, "Attempting to remove non-existance node\n");
		//return ( NullData );
		return( FALSE );
		}

	// follow pointer chain from head or tail to requested element
	// depending upon which chain is shorter

	if(Index < ArraySize / 2)
		{
		// element closer to head => follow chain forward from first
		dl = first;
		++Index;
		while(--Index > 0)
			{
			dl = dl->next;
			}
		}
		else
		{
		// element closer to tail => follow chain backward from last
		dl = last;
		Index = (ArraySize - Index);
		while(--Index > 0)
			{
			dl = dl->prev;
			}
		}

	// relink chain around element to be deleted
	// fix first or last pointer if element to delete is first or last

	if(dl->prev)
		dl->prev->next = dl->next;
	else
		first = dl->next;

	if(dl->next)
		dl->next->prev = dl->prev;
	else
		last = dl->prev;

	delete dl;
	--ArraySize;
	return ( TRUE );
	}

/****************************************************************
 * Test Functions
 *
 *
 ****************************************************************/

#	ifdef	BUILD_TEST_UNITS

int
testfunc()
	{
	unsigned	int	Index;
	Array<int>	AInt;

	Index = 0;
	while(Index < 10)
		{
		AInt.Add(Index * 2);
		++Index;
		}
	Index = 0;
	while(Index < 10)
		{
		printf("Val: %d : %d\n", Index, AInt.RemoveAt(0));
		++Index;
		}
	return ( 0 );
	}

int
main()
	{
	testfunc();
	fprintf(stderr, "Display Should be like 'Val: x: 2*x' with x[0..9]\n");
	}

#	endif