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403 lines
7.1 KiB
C++
403 lines
7.1 KiB
C++
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/**
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* This file defines the binary tree class and it
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* nsNode child class.
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*
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* This simple version stores nodes, and the
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* nodes store void* ptrs.
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*
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* @update gess 4/11/98
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* @param
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* @return
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*/
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#include "nsBTree.h"
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/**
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* default constructor
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*
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* @update gess 4/11/98
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*/
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nsNode::nsNode(){
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mLeft=0;
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mRight=0;
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mParent=0;
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mColor=eBlack;
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}
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/**
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* Copy constructor
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*
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* @update gess 4/11/98
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* @param
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* @return
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*/
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nsNode::nsNode(const nsNode& aNode){
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mLeft=aNode.mLeft;
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mRight=aNode.mRight;
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mParent=aNode.mParent;
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mColor=aNode.mColor;
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}
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/**
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* destructor
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*
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* @update gess 4/11/98
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*/
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nsNode::~nsNode(){
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}
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/**
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* Retrive ptr to parent node
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*
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* @update gess 4/11/98
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* @return ptr to parent node
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*/
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nsNode* nsNode::GetParentNode(void) const{
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return mParent;
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}
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/**
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* Retrieve ptr to left (less) node
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*
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* @update gess 4/11/98
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* @return ptr to left (may be NULL)
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*/
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nsNode* nsNode::GetLeftNode(void) const{
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return mLeft;
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}
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/**
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* Retrieve ptr to right (more) node
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*
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* @update gess 4/11/98
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* @return ptr to right node (may be NULL)
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*/
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nsNode* nsNode::GetRightNode(void) const{
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return mRight;
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}
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/**
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*
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*
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* @update gess 4/11/98
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* @param
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* @return
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*/
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nsNode& nsNode::operator=(const nsNode& aNode){
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if(this!=&aNode){
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mLeft=aNode.mLeft;
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mRight=aNode.mRight;
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mParent=aNode.mParent;
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mColor=aNode.mColor;
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}
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return *this;
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}
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/********************************************************
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* Here comes the BTREE class...
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********************************************************/
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/**
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* nsBTree constructor
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*
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* @update gess 4/11/98
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*/
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nsBTree::nsBTree(){
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mRoot=0;
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}
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/**
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* destructor
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*
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* @update gess 4/11/98
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*/
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nsBTree::~nsBTree(){
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if(mRoot){
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//walk the tree and destroy the children.
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}
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}
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/**
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* Given a node, we're supposed to add it into
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* our tree.
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*
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* @update gess 4/11/98
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* @param aNode to be added to tree
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* @return ptr to added node or NULL
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*/
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nsNode* nsBTree::Add(nsNode& aNode){
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nsNode* node1=mRoot; //x
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nsNode* node2=0; //y
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while(node1) {
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node2=node1;
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if(aNode<*node1)
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node1=node1->mLeft;
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else node1=node1->mRight;
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}
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aNode.mParent=node2;
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if(!node2){
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mRoot=&aNode;
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}
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else{
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if(aNode<*node2)
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node2->mLeft=&aNode;
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else node2->mRight=&aNode;
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}
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return &aNode;
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}
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/**
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* Removes given node from tree if present.
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*
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* @update gess 4/11/98
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* @param aNode to be found and removed
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* @return ptr to remove node, or NULL
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*/
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nsNode* nsBTree::Remove(nsNode& aNode){
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nsNode* result=0;
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nsNode* node3=Find(aNode);
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if(node3) {
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nsNode* node1;
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nsNode* node2;
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if((!node3->mLeft) || (!node3->mRight))
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node2=node3;
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else node2=After(*node3);
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if(node2->mLeft)
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node1=node2->mLeft;
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else node1=node2->mRight;
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if(node1)
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node1->mParent=node2->mParent;
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if(node2->mParent) {
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if(node2==node2->mParent->mLeft)
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node2->mParent->mLeft=node1;
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else node2->mParent->mRight=node1;
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}
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else mRoot=node1;
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if(node2!=node3)
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(*node3)==(*node2);
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if(node2->mColor == nsNode::eBlack)
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ReBalance(*node1);
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delete node2;
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result=&aNode;
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}
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return result;
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}
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/**
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* Clears the tree of any data.
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* Be careful here if your objects are heap based!
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* This method doesn't free the objects, so if you
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* don't have your own pointers, they will become
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* orphaned.
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*
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* @update gess 4/11/98
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* @param
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* @return this
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*/
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nsBTree& nsBTree::Empty(nsNode* aNode) {
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mRoot=0;
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return *this;
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}
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/**
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* This method destroys all the objects in the tree.
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* WARNING: Never call this method on stored objects
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* that are stack-based!
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*
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* @update gess 4/11/98
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* @param
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* @return this
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*/
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nsBTree& nsBTree::Erase(nsNode* aNode){
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// nsNode* node1 =(aNode) ? aNode : mRoot;
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if(aNode) {
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Erase(aNode->mLeft); //begin by walking left side
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Erase(aNode->mRight); //then search right side
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delete aNode; //until a leaf, then delete
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}
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return *this;
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}
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/**
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* Retrieve ptr to first node in tree
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*
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* @update gess 4/11/98
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* @return
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*/
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nsNode* nsBTree::First(void) const{
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if(mRoot)
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return First(*mRoot);
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return 0;
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}
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/**
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* Retrive ptr to first node rel to given node
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*
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* @update gess 4/11/98
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* @param node to begin scan from
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* @return ptr to first node from given node or NULL
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*/
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nsNode* nsBTree::First(const nsNode& aNode) const{
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nsNode* result=0;
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if(mRoot) {
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result=mRoot;
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while(result->GetLeftNode()) {
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result=result->GetLeftNode();
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}
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}
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return result;
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}
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/**
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* Retrive ptr to last node
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*
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* @update gess 4/11/98
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* @return ptr to last node rel to root or NULL
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*/
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nsNode* nsBTree::Last(void) const{
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if(mRoot)
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return Last(*mRoot);
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return 0;
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}
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/**
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* Retrive ptr to last node rel to given node
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*
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* @update gess 4/11/98
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* @param node to begin scan from
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* @return ptr to first node from given node or NULL
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*/
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nsNode* nsBTree::Last(const nsNode& aNode) const{
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nsNode* result=0;
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if(mRoot) {
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result=mRoot;
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while(result->GetRightNode()) {
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result=result->GetRightNode();
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}
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}
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return result;
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}
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/**
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* Retrive ptr to prior node rel to given node
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*
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* @update gess 4/11/98
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* @param node to begin scan from
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* @return ptr to prior node from given node or NULL
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*/
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nsNode* nsBTree::Before(const nsNode& aNode) const{
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if(aNode.GetLeftNode())
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return Last(*aNode.GetLeftNode());
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//otherwise...
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nsNode* node1=(nsNode*)&aNode;
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nsNode* node2=aNode.GetParentNode();
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while((node2) && (node1==node2->GetLeftNode())) {
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node1=node2;
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node2=node2->GetParentNode();
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}
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return node2;
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}
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/**
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* Retrive ptr to next node rel to given node
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*
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* @update gess 4/11/98
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* @param node to begin scan from
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* @return ptr to next node from given node or NULL
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*/
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nsNode* nsBTree::After(const nsNode& aNode) const{
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if(aNode.GetRightNode())
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return First(*aNode.GetRightNode());
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//otherwise...
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nsNode* node1=(nsNode*)&aNode;
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nsNode* node2=aNode.GetParentNode();
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while((node2) && (node1==node2->GetRightNode())) {
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node1=node2;
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node2=node2->GetParentNode();
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}
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return node2;
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}
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/**
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* Scan for given node
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*
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* @update gess 4/11/98
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* @param node to find
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* @return ptr to given node, or NULL
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*/
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nsNode* nsBTree::Find(const nsNode& aNode) const{
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nsNode* result=mRoot;
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while((result) && (!(aNode==(*result)))) {
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if(aNode<*result)
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result=result->mLeft;
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else result=result->mRight;
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}
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return (nsNode*)result;
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}
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/**
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* Rebalances tree around the given node. This only
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* needs to be called after a node is deleted.
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* This method does nothing for btrees, but is
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* needed for RBTrees.
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*
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* @update gess 4/11/98
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* @param aNode -- node to balance around
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* @return this
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*/
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nsBTree& nsBTree::ReBalance(nsNode& aNode){
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return *this;
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}
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/**
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*
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*
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* @update gess 4/11/98
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* @param
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* @return
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*/
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const nsBTree& nsBTree::ForEach(nsNodeFunctor& aFunctor,nsNode* aNode) const{
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nsNode* node1 =(aNode) ? aNode : mRoot;
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if(node1) {
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if(node1->mLeft)
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ForEach(aFunctor,node1->mLeft); //begin by walking left side
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aFunctor(*node1);
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if(node1->mRight)
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ForEach(aFunctor,node1->mRight); //then search right side
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}
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return *this;
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}
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