MFC D3D Application: Direct3D Tutorial: Part I

//----------------------------------------------------------------------------
// CTArray.h: C++ template based class for dynamic arrays.
//
// 10/15/05 - Michael B. Comet, comet@comet-cartoons.com - Initial Rev
// 05/20/06 - tor - no ostream cout friends, renamed most of the members.
// 06/05/06 - tor - qsort wrapper with input sort callback
// 06/21/06 - tor - Find returning an index, not a boolean
// 08/23/06 - tor - Find with optional start index, to find duplicates
// 08/24/06 - tor - GetAll to a void ptr of specified size
// 08/25/06 - tor - some methods are now virtual for subclass overrides
// 08/26/06 - tor - swap
//----------------------------------------------------------------------------

#ifndef _CTARRAY_H_
#define _CTARRAY_H_

template<class TYPE> class CTArray
{
private:
	UINT	nSize;	// actual size
	UINT	nGrow;	// grow factor

protected:
	UINT	nItems;	// number of elements (as it appears to the user)
	TYPE*	pData;	// pointer to array of data

public:
	// blank constructor
	CTArray() { Init(); }
	
	// copy constructor
	CTArray(CTArray& Src) { Init(); Copy(Src); }
	
	// typed copy constructor
	CTArray(const TYPE* pSrc, UINT nCount = 1)
	{
		Init();
		SetLength(nCount);
		
		for (UINT u = 0; u < nItems; u++) pData[u] = pSrc[u];
	}

	// typed initializing constructor
	CTArray(UINT nCount, TYPE Src)
	{
		Init();
		SetLength(nCount);
		
		for (UINT u = 0; u < nItems; u++) pData[u] = Src;
	}

	// operators
	const TYPE& operator[](UINT nIndex) const { return pData[nIndex]; }
	TYPE&		operator[](UINT nIndex)		  { return pData[nIndex]; }
	CTArray&	operator=(CTArray& Src)		  { Copy(Src); return *this; }

	// initialise
	void Init() { pData = NULL; nSize = nItems = 0; nGrow = 8; }

	// release data
	virtual void Clear(void) { if (pData != NULL) delete [] pData; Init(); }

	// copy from other
	void Copy(CTArray& Src)
	{
		Clear();
		SetLength(Src.Length());
		
		for (UINT u = 0; u < nItems; u++) pData[u] = Src.pData[u];
	}

	// grow factor get/set
	UINT GrowFactor(void) const { return nGrow; }
	void SetGrowFactor(UINT nNewGrow) { nGrow = nNewGrow; if (nGrow == 0) nGrow = 1; }

	// length (items) get
	UINT Length(void) { return nItems; }
	
	// set length regrow or shrink
	virtual bool SetLength(UINT nLength, bool bForce = false)
	{
		if (nLength == 0)
		{
			Clear();
			return true;
		}
		
		// alloc new storage
		TYPE* pNewData = NULL;
		
		UINT nNewSize = ((nLength / nGrow) + 1) * nGrow;
		
		// grow only if either the amount we need is greater than what we have
		// already or if the amount is <= 1/2, whatever's smaller
		if (nNewSize > nSize || nNewSize <= nSize / 2 || bForce)
		{
			if ((pNewData = new TYPE[nNewSize]) == NULL)
				return false;
			
			// now copy the old elements into the new array, up to the old
			// number of items or to the user-set new length,  whichever's
			// smaller
			for (UINT u = 0; u < nItems && u < nLength; u++)
				pNewData[u] = pData[u];
			
			// update all the current info...
			if (pData != NULL)
				delete [] pData;
			
			pData = pNewData;
			nSize = nNewSize;
		}
		
		nItems = nLength;
		
		return true;
	}
	
	// set w/bounds check but no grow
	virtual bool Set(UINT nIndex, TYPE Src) const
	{
		if (nIndex >= nItems || pData == NULL)
			return false;

		pData[nIndex] = Src;

		return true;
	}

	// get w/bounds check but no grow
	virtual bool Get(TYPE& Dst, UINT nIndex) const
	{
		if (nIndex >= nItems || pData == NULL)
			return false;

		Dst = pData[nIndex];

		return true;
	}

	// get all elements to a typed pointer; do not forget to delete
	// such pointer after no longer needed
	UINT GetAll(TYPE*& pDst)
	{
		pDst = new TYPE[nItems];

		for (UINT u = 0; u < nItems; u++)
			pDst[u] = pData[u];

		return nItems;
	}

	// get all elements to an unknown size pointer of specified size; the
	// pointer must be initialized by the caller...
	UINT GetAll(void* pDst, int nSize)
	{
		for (UINT u = 0; u < nItems; u++)
			memcpy((void*)((BYTE*)pDst + u * nSize), (void*)(&pData[u]), nSize);

		return nItems;
	}

	// remove element at given position
	virtual bool Remove(UINT nIndex)
	{
		if (nItems == 0 || pData == NULL)
			return false;

		// starting with the element we are removing, work up
		// copying each next value down to the current spot...
		for (UINT u = nIndex; u < nItems - 1 ; u++)
			pData[u] = pData[u + 1];

		// this will either simply change the nItems value or realloc and
		// free some memory
		SetLength(nItems - 1);

		return true;
	}
	
	// insert element at given position
	virtual void Insert(TYPE Src, UINT nIndex)
	{
		// first, make room
		SetLength(nItems + 1);

		// starting with the last element work back until we get to the one
		// we are inserting at and copy forward
		for (UINT u = nItems - 1; u > nIndex; u--)
			pData[u] = pData[u - 1] ;	

		// finally insert new value
		pData[nIndex] = Src;
	}

	// append element to the end of array
	virtual int Append(TYPE Src)
	{
		// first, make room
		SetLength(nItems + 1);

		// insert new value
		pData[nItems - 1] = Src;

		return nItems;
	}

	// blank append
	virtual int Append()
	{
		// just make room
		SetLength(nItems + 1);
		
		return nItems;
	}

	// finder with mem compare and optional start
	int Find(TYPE Src, UINT nStart = 0)
	{
		for (UINT u = nStart; u < nItems; u++)
		{
			if (memcmp(&pData[u], &Src, sizeof(TYPE)) == 0)
				return (int)u;
		}

		return -1;
	}

	// swap
	void Swap(UINT i, UINT j)
	{
		if (i >= nItems || j >= nItems || i == j)
			return;

		TYPE Tmp = pData[i];
		pData[i] = pData[j];
		pData[j] = Tmp;
	}

	// sort wrapper with callback and method
	void Sort(int (__cdecl* compare)(const void* p1, const void* p2), int nMethod = 0)
	{
		switch (nMethod)
		{
		case 1:
		{
			// sort the array with fixed starting items, by comparing neighbors
			for (UINT i = 0; i < nItems - 1; i++)
			{
				// skip a neighbor that is in order (as determined by a non-zero
				// return from the compare function)
				if (compare((const void*)&pData[i], (const void*)&pData[i + 1]))
					continue;

				// search for an item matching the last starting item
				UINT j = i + 1;
				
				while (!compare((const void*)&pData[i], (const void*)&pData[j]) && j < nItems - 1)
					j++;
				
				// swap the matching item to be right below the starting item
				if (j <= nItems - 1)
					Swap(i + 1, j);
			}
			
			break;
		}
		default:
			qsort(pData, nItems, sizeof(TYPE), compare);
			break;
		}
	}

	// destructor
	~CTArray() { Clear(); }
};

typedef CTArray<DWORD> DWORDARRAY;

#endif // _CTARRAY_H_