N-gram and Fast Pattern Extraction Algorithm

// BinaryTree.h:	interface for the CBinaryTree template.
// Inventor Name:	Hatem Mostafa
// Created:			18/1/2003
// Modified:		20/12/2004
//
//////////////////////////////////////////////////////////////////////

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <malloc.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <io.h>

#define TREENODE CBinaryTreeNode<KEY, DATA>
#define LEFT	Childs[0]
#define RIGHT	Childs[1]

template <class KEY, class DATA> class CBinaryTreeNode
{
public:
	CBinaryTreeNode()
	{
		Parent = LEFT = RIGHT = NULL;
		Count = ID = 0;
		pnEqualIDs = NULL;
		nEqualIDsIndex = nEqualIDsSize = 0;
	}
	~CBinaryTreeNode()
	{
		if(pnEqualIDs)
			free(pnEqualIDs);
	}
public:
	// node parent, left, right respectively
	TREENODE *Parent, *Childs[2];
	// node key
	KEY Key;
	// node data
	DATA Data;
	// node repetition count
	int Count;
	// node ID
	int ID;
	// node repeated keys' IDs
	int *pnEqualIDs, nEqualIDsIndex, nEqualIDsSize;
	const TREENODE& operator=(const TREENODE& node)
	{
		Key = node.Key;
		Data = node.Data;
		Count = node.Count;
		ID = node.ID;
		if(node.pnEqualIDs)
		{
			if(pnEqualIDs == NULL)
			{
				nEqualIDsSize = node.nEqualIDsSize;
				pnEqualIDs = (int*)malloc(nEqualIDsSize);
			}
			else	if(nEqualIDsSize < node.nEqualIDsSize)
			{
				nEqualIDsSize = node.nEqualIDsSize;
				pnEqualIDs = (int*)realloc(pnEqualIDs, nEqualIDsSize);
			}
			memcpy(pnEqualIDs, node.pnEqualIDs, node.nEqualIDsSize);
			nEqualIDsIndex = node.nEqualIDsIndex;
		}
		return *this;
	}
};

template <class KEY, class ARG_KEY, class DATA, class ARG_DATA> class CBinaryTree
{
public:
	CBinaryTree()
	{
		Root = Nil = NULL;
		Count = Serial = 0;
		Modified = NoRepeat = false;
	}
	~CBinaryTree()
	{
		RemoveAll();
	}
public:
	// tree root node
	TREENODE* Root, * Nil;
	// tree nodes count
	int Count, Serial;
	// flag to indicate if the tree is modified or not
	bool Modified;
	// ignore repeated keys in the Insert function
	bool NoRepeat;

	// return tree nodes count
	inline int GetCount() const	{	return Count;	}
	// check if the tree is empty or not
	inline bool IsEmpty() const	{	return Count == 0;	}
	// remove all tree nodes
	void RemoveAll()
	{
		TREENODE *node = Root, *pTemp;
		while(node != Nil)
		{
			// check for left child
			if(node->LEFT != Nil)
				node = node->LEFT;
			// check for right child
			else	if(node->RIGHT != Nil)
				node = node->RIGHT;
			else	// node has no children
			{	// save node pointer
				pTemp = node;
				// set node pointer at its parent to NULL
				if(node->Parent != Nil)
					node->Parent->Childs[node != node->Parent->LEFT] = Nil;
				// update pointer node to its parent
				node = node->Parent;
				// delete the saved node
				delete pTemp;
			}
		}
		Count = Serial = 0;
		Root = Nil;
		Modified = false;
	}
	// insert key in the tree
	inline TREENODE* Insert(ARG_KEY key, int nID = -1, TREENODE* node = NULL)
	{
		if(Root == Nil)
		{
			Root = NewNode();
			node = Root;
		}
		else	
		{
			if(node == NULL)
				node = Root;
			int nResult;
			while(true)
			{
				nResult = node->Key.compare(key);
				if(nResult == 0)
				{
					node->Count++;
					if(NoRepeat == false)
					{
						if(node->pnEqualIDs == NULL)
						{
							node->nEqualIDsSize = 100;
							node->pnEqualIDs = (int*)malloc(node->nEqualIDsSize);
						}
						else	if((int)(node->nEqualIDsIndex*sizeof(int)) >= node->nEqualIDsSize)
						{
							node->nEqualIDsSize += 100;
							node->pnEqualIDs = (int*)realloc(node->pnEqualIDs, node->nEqualIDsSize);
						}
						node->pnEqualIDs[node->nEqualIDsIndex++] = nID == -1 ? Serial : nID;
						Serial++;
						Count++;
					}
					return node;
				}
				nResult = nResult > 0 ? 0 : 1;
				if(node->Childs[nResult] == Nil)
				{
					node->Childs[nResult] = NewNode();
					node->Childs[nResult]->Parent = node;
					node = node->Childs[nResult];
					break;
				}
				node = node->Childs[nResult];
			}	
		}
		node->Key = key;
		node->ID = nID == -1 ? Serial : nID;
		Serial++;
		Count++;
		node->Count++;
		Modified = true;
		
		return node;
	}	
	inline TREENODE* InsertEx(ARG_KEY key, int nID, TREENODE* node, bool bRight)
	{
		if(Root == Nil)
		{
			Root = NewNode();
			node = Root;
		}
		else	
		{
			node->Childs[bRight] = NewNode();
			node->Childs[bRight]->Parent = node;
			node = node->Childs[bRight];
		}
		node->Key = key;
		node->ID = nID;
		node->Count++;
		Serial++;
		Count++;

		return node;
	}
	// search for a key in the tree
	inline TREENODE* Search(ARG_KEY key, TREENODE* node = NULL) const
	{
		if(node == NULL)
			node = Root;
		int nResult;
		while(node != Nil && (nResult = node->Key.compare(key)) != 0)
			node = node->Childs[nResult < 0];
		return node == Nil ? NULL : node;
	}	
	// return minimum key in the tree
	TREENODE* Min(TREENODE* node) const
	{	
		// iterate in the left branch
		while(node != Nil && node->LEFT != Nil)
			node = node->LEFT;
		return node;
	}
	// return maximum key in the tree
	TREENODE* Max(TREENODE* node) const
	{	
		// iterate in the right branch
		while(node != Nil && node->RIGHT != Nil)
			node = node->RIGHT;
		return node;
	}
	// return node successor
	TREENODE* Successor(TREENODE* node) const
	{
		// return the left most node in the right subtree
		if(node->RIGHT != Nil)
			return Min(node->RIGHT);
		// go up from node until we find a node that is the left of its parent
		TREENODE* Parent = node->Parent;
		while(Parent != Nil && node == Parent->RIGHT)
		{
			node = Parent;
			Parent = node->Parent;
		}
		return Parent;
	}
	// return node predecessor
	TREENODE* Predecessor(TREENODE* node) const
	{	
		// return the right most node in the left subtree
		if(node->LEFT != Nil)
			return Max(node->LEFT);
		// go up from node until we find a node that is the right of its parent
		TREENODE* Parent = node->Parent;
		while(Parent != Nil && node == Parent->LEFT)
		{
			node = Parent;
			Parent = node->Parent;
		}
		return Parent;
	}

	// delete node
	// 1- node has no child, remove it
	// 2- node has one child, splice it (connect its parent and child)
	// 3- node has two childs, splice its successor and put it in its place
	void Delete(TREENODE* node)
	{	
		TREENODE *pSplice = (node->LEFT == Nil || node->RIGHT == Nil)?node:Successor(node);
		TREENODE *pChild = pSplice->Childs[pSplice->LEFT == Nil];
		// connect child to spliced node parent
		if(pChild != Nil)
			pChild->Parent = pSplice->Parent;
		// connect spliced node parent to child
		if(pSplice->Parent == Nil)
			Root = pChild;
		else
			pSplice->Parent->Childs[pSplice != pSplice->Parent->LEFT] = pChild;
		// put spliced node in place of node (if required)
		if(pSplice != node)
		{	
			// copy spliced node
			*node = *pSplice;
			// delete the spliced node
			delete pSplice;
		}
		else
			// delete the node
			delete node;
		Count--;
	}

	// save all tree nodes in an integer pointer allocated with GetCount() size 
	void Save(int* pArray, bool bAscending = true, bool (* lpfn)(int, int) = NULL)
	{
		int nIndex = 0;
		TREENODE* node = bAscending ? Min(Root) : Max(Root);
		while(node != Nil)
		{
			if(lpfn)
				(*lpfn)(nIndex++, Count);
			SaveNode(node, pArray);
			node = bAscending ? Successor(node) : Predecessor(node);
		}
		Modified = false;
	}
	// save to file
	void Save(LPCSTR lpcsFileName, bool bAscending = true, bool (* lpfn)(int, int) = NULL)
	{
		int *pArray = (int*)malloc(Count*sizeof(int));
		Save(pArray, bAscending, lpfn);
		
		int nFile = _open(lpcsFileName, _O_BINARY|_O_CREAT|_O_RDWR, _S_IREAD|_S_IWRITE);
		_write(nFile, pArray, Count*sizeof(int));
		_close(nFile);
		
		free(pArray);
	}
	// save one node
	void SaveNode(TREENODE* node, int*& pArray)
	{
		*pArray++ = node->ID;
		if(node->pnEqualIDs)
		{
			memcpy(pArray, node->pnEqualIDs, node->nEqualIDsIndex*sizeof(int));
			pArray += node->nEqualIDsIndex;
		}
	}
protected:
	virtual TREENODE* NewNode()
	{
		return new TREENODE();
	}
};