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609 lines
13 KiB
C++
609 lines
13 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1999 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#include "nsAVLTree.h"
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enum eLean {eLeft,eNeutral,eRight};
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struct NS_COM nsAVLNode {
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public:
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nsAVLNode(void* aValue) {
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mLeft=0;
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mRight=0;
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mSkew=eNeutral;
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mValue=aValue;
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}
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nsAVLNode* mLeft;
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nsAVLNode* mRight;
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eLean mSkew;
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void* mValue;
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};
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/************************************************************
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Now begin the tree class. Don't forget that the comparison
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between nodes must occur via the comparitor function,
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otherwise all you're testing is pointer addresses.
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************************************************************/
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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nsAVLTree::nsAVLTree(nsAVLNodeComparitor& aComparitor,
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nsAVLNodeFunctor* aDeallocator) :
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mComparitor(aComparitor), mDeallocator(aDeallocator) {
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mRoot=0;
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mCount=0;
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}
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/**
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*
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* @update gess12/27/98
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* @param
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* @return
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*/
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nsAVLTree::~nsAVLTree(){
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if (mDeallocator) {
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ForEachDepthFirst(*mDeallocator);
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}
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}
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class CDoesntExist: public nsAVLNodeFunctor {
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public:
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CDoesntExist(const nsAVLTree& anotherTree) : mOtherTree(anotherTree) {
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}
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virtual void* operator()(void* anItem) {
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void* result=mOtherTree.FindItem(anItem);
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if(result)
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return nsnull;
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return anItem;
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}
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protected:
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const nsAVLTree& mOtherTree;
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};
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/**
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* This method compares two trees (members by identity).
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* @update gess12/27/98
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* @param tree to compare against
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* @return true if they are identical (contain same stuff).
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*/
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PRBool nsAVLTree::operator==(const nsAVLTree& aCopy) const{
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CDoesntExist functor(aCopy);
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void* theItem=FirstThat(functor);
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PRBool result=PRBool(!theItem);
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return result;
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}
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/**
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*
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* @update gess12/27/98
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* @param
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* @return
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*/
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static void
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avlRotateRight(nsAVLNode*& aRootNode){
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nsAVLNode* ptr2;
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nsAVLNode* ptr3;
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ptr2=aRootNode->mRight;
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if(ptr2->mSkew==eRight) {
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aRootNode->mRight=ptr2->mLeft;
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ptr2->mLeft=aRootNode;
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aRootNode->mSkew=eNeutral;
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aRootNode=ptr2;
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}
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else {
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ptr3=ptr2->mLeft;
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ptr2->mLeft=ptr3->mRight;
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ptr3->mRight=ptr2;
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aRootNode->mRight=ptr3->mLeft;
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ptr3->mLeft=aRootNode;
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if(ptr3->mSkew==eLeft)
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ptr2->mSkew=eRight;
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else ptr2->mSkew=eNeutral;
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if(ptr3->mSkew==eRight)
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aRootNode->mSkew=eLeft;
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else aRootNode->mSkew=eNeutral;
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aRootNode=ptr3;
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}
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aRootNode->mSkew=eNeutral;
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return;
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}
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/**
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*
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* @update gess12/27/98
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* @param
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* @return
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*/
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static void
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avlRotateLeft(nsAVLNode*& aRootNode){
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nsAVLNode* ptr2;
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nsAVLNode* ptr3;
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ptr2=aRootNode->mLeft;
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if(ptr2->mSkew==eLeft) {
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aRootNode->mLeft=ptr2->mRight;
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ptr2->mRight=aRootNode;
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aRootNode->mSkew=eNeutral;
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aRootNode=ptr2;
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}
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else {
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ptr3=ptr2->mRight;
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ptr2->mRight=ptr3->mLeft;
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ptr3->mLeft=ptr2;
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aRootNode->mLeft=ptr3->mRight;
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ptr3->mRight=aRootNode;
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if(ptr3->mSkew==eRight)
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ptr2->mSkew=eLeft;
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else ptr2->mSkew=eNeutral;
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if(ptr3->mSkew==eLeft)
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aRootNode->mSkew=eRight;
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else aRootNode->mSkew=eNeutral;
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aRootNode=ptr3;
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}
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aRootNode->mSkew=eNeutral;
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return;
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}
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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static eAVLStatus
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avlInsert(nsAVLNode*& aRootNode, nsAVLNode* aNewNode,
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nsAVLNodeComparitor& aComparitor) {
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eAVLStatus result=eAVL_unknown;
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if(!aRootNode) {
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aRootNode = aNewNode;
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return eAVL_ok;
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}
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if(aNewNode==aRootNode->mValue) {
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return eAVL_duplicate;
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}
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PRInt32 theCompareResult=aComparitor(aRootNode->mValue,aNewNode->mValue);
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if(0 < theCompareResult) { //if(anItem<aRootNode->mValue)
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result=avlInsert(aRootNode->mLeft,aNewNode,aComparitor);
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if(eAVL_ok==result) {
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switch(aRootNode->mSkew){
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case eLeft:
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avlRotateLeft(aRootNode);
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result=eAVL_fail;
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break;
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case eRight:
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aRootNode->mSkew=eNeutral;
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result=eAVL_fail;
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break;
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case eNeutral:
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aRootNode->mSkew=eLeft;
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break;
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} //switch
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}//if
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} //if
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else {
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result=avlInsert(aRootNode->mRight,aNewNode,aComparitor);
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if(eAVL_ok==result) {
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switch(aRootNode->mSkew){
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case eLeft:
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aRootNode->mSkew=eNeutral;
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result=eAVL_fail;
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break;
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case eRight:
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avlRotateRight(aRootNode);
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result=eAVL_fail;
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break;
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case eNeutral:
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aRootNode->mSkew=eRight;
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break;
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} //switch
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}
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} //if
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return result;
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}
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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static void
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avlBalanceLeft(nsAVLNode*& aRootNode, PRBool& delOk){
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nsAVLNode* ptr2;
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nsAVLNode* ptr3;
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eLean balnc2;
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eLean balnc3;
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switch(aRootNode->mSkew){
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case eLeft:
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ptr2=aRootNode->mLeft;
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balnc2=ptr2->mSkew;
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if(balnc2!=eRight) {
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aRootNode->mLeft=ptr2->mRight;
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ptr2->mRight=aRootNode;
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if(balnc2==eNeutral){
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aRootNode->mSkew=eLeft;
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ptr2->mSkew=eRight;
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delOk=PR_FALSE;
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}
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else{
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aRootNode->mSkew=eNeutral;
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ptr2->mSkew=eNeutral;
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}
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aRootNode=ptr2;
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}
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else{
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ptr3=ptr2->mRight;
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balnc3=ptr3->mSkew;
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ptr2->mRight=ptr3->mLeft;
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ptr3->mLeft=ptr2;
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aRootNode->mLeft=ptr3->mRight;
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ptr3->mRight=aRootNode;
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if(balnc3==eRight) {
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ptr2->mSkew=eLeft;
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}
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else {
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ptr2->mSkew=eNeutral;
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}
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if(balnc3==eLeft) {
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aRootNode->mSkew=eRight;
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}
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else {
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aRootNode->mSkew=eNeutral;
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}
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aRootNode=ptr3;
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ptr3->mSkew=eNeutral;
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}
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break;
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case eRight:
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aRootNode->mSkew=eNeutral;
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break;
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case eNeutral:
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aRootNode->mSkew=eLeft;
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delOk=PR_FALSE;
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break;
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}//switch
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return;
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}
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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static void
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avlBalanceRight(nsAVLNode*& aRootNode, PRBool& delOk){
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nsAVLNode* ptr2;
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nsAVLNode* ptr3;
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eLean balnc2;
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eLean balnc3;
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switch(aRootNode->mSkew){
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case eLeft:
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aRootNode->mSkew=eNeutral;
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break;
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case eRight:
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ptr2=aRootNode->mRight;
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balnc2=ptr2->mSkew;
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if(balnc2!=eLeft) {
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aRootNode->mRight=ptr2->mLeft;
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ptr2->mLeft=aRootNode;
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if(balnc2==eNeutral){
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aRootNode->mSkew=eRight;
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ptr2->mSkew=eLeft;
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delOk=PR_FALSE;
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}
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else{
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aRootNode->mSkew=eNeutral;
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ptr2->mSkew=eNeutral;
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}
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aRootNode=ptr2;
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}
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else{
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ptr3=ptr2->mLeft;
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balnc3=ptr3->mSkew;
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ptr2->mLeft=ptr3->mRight;
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ptr3->mRight=ptr2;
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aRootNode->mRight=ptr3->mLeft;
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ptr3->mLeft=aRootNode;
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if(balnc3==eLeft) {
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ptr2->mSkew=eRight;
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}
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else {
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ptr2->mSkew=eNeutral;
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}
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if(balnc3==eRight) {
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aRootNode->mSkew=eLeft;
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}
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else {
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aRootNode->mSkew=eNeutral;
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}
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aRootNode=ptr3;
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ptr3->mSkew=eNeutral;
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}
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break;
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case eNeutral:
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aRootNode->mSkew=eRight;
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delOk=PR_FALSE;
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break;
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}//switch
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return;
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}
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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static eAVLStatus
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avlRemoveChildren(nsAVLNode*& aRootNode,nsAVLNode*& anotherNode, PRBool& delOk){
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eAVLStatus result=eAVL_ok;
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if(!anotherNode->mRight){
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aRootNode->mValue=anotherNode->mValue; //swap
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anotherNode=anotherNode->mLeft;
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delOk=PR_TRUE;
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}
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else{
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avlRemoveChildren(aRootNode,anotherNode->mRight,delOk);
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if(delOk)
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avlBalanceLeft(anotherNode,delOk);
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}
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return result;
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}
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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static eAVLStatus
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avlRemove(nsAVLNode*& aRootNode, void* anItem, PRBool& delOk,
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nsAVLNodeComparitor& aComparitor){
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eAVLStatus result=eAVL_ok;
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if(!aRootNode)
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delOk=PR_FALSE;
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else {
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PRInt32 cmp=aComparitor(anItem,aRootNode->mValue);
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if(cmp<0){
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avlRemove(aRootNode->mLeft,anItem,delOk,aComparitor);
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if(delOk)
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avlBalanceRight(aRootNode,delOk);
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}
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else if(cmp>0){
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avlRemove(aRootNode->mRight,anItem,delOk,aComparitor);
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if(delOk)
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avlBalanceLeft(aRootNode,delOk);
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}
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else{ //they match...
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nsAVLNode* temp=aRootNode;
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if(!aRootNode->mRight) {
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aRootNode=aRootNode->mLeft;
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delOk=PR_TRUE;
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delete temp;
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}
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else if(!aRootNode->mLeft) {
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aRootNode=aRootNode->mRight;
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delOk=PR_TRUE;
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delete temp;
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}
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else {
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avlRemoveChildren(aRootNode,aRootNode->mLeft,delOk);
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if(delOk)
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avlBalanceRight(aRootNode,delOk);
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}
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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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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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eAVLStatus
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nsAVLTree::AddItem(void* anItem){
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eAVLStatus result=eAVL_ok;
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nsAVLNode* theNewNode=new nsAVLNode(anItem);
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result=avlInsert(mRoot,theNewNode,mComparitor);
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if(eAVL_duplicate!=result)
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mCount++;
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else {
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delete theNewNode;
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}
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return result;
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}
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/** ------------------------------------------------
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*
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*
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* @update gess 4/22/98
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* @param
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* @return
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*/ //----------------------------------------------
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void* nsAVLTree::FindItem(void* aValue) const{
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nsAVLNode* result=mRoot;
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PRInt32 count=0;
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while(result) {
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count++;
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PRInt32 cmp=mComparitor(aValue,result->mValue);
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if(0==cmp) {
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//we matched...
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break;
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}
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else if(0>cmp){
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//theNode was greater...
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result=result->mLeft;
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}
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else {
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//aValue is greater...
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result=result->mRight;
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}
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}
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if(result) {
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return result->mValue;
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}
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return nsnull;
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}
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/**
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*
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* @update gess12/30/98
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* @param
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* @return
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*/
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eAVLStatus
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nsAVLTree::RemoveItem(void* aValue){
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PRBool delOk=PR_TRUE;
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eAVLStatus result=avlRemove(mRoot,aValue,delOk,mComparitor);
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if(eAVL_ok==result)
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mCount--;
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return result;
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}
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/**
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*
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* @update gess9/11/98
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* @param
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* @return
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*/
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static void
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avlForEachDepthFirst(nsAVLNode* aNode, nsAVLNodeFunctor& aFunctor){
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if(aNode) {
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avlForEachDepthFirst(aNode->mLeft,aFunctor);
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avlForEachDepthFirst(aNode->mRight,aFunctor);
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aFunctor(aNode->mValue);
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}
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}
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/**
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*
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* @update gess9/11/98
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* @param
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* @return
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*/
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void
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nsAVLTree::ForEachDepthFirst(nsAVLNodeFunctor& aFunctor) const{
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::avlForEachDepthFirst(mRoot,aFunctor);
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}
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/**
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*
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* @update gess9/11/98
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* @param
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* @return
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*/
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static void
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avlForEach(nsAVLNode* aNode, nsAVLNodeFunctor& aFunctor) {
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if(aNode) {
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avlForEach(aNode->mLeft,aFunctor);
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aFunctor(aNode->mValue);
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avlForEach(aNode->mRight,aFunctor);
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}
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}
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/**
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*
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* @update gess9/11/98
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* @param
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* @return
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*/
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void
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nsAVLTree::ForEach(nsAVLNodeFunctor& aFunctor) const{
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::avlForEach(mRoot,aFunctor);
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}
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/**
|
|
*
|
|
* @update gess9/11/98
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|
* @param
|
|
* @return
|
|
*/
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|
static void*
|
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avlFirstThat(nsAVLNode* aNode, nsAVLNodeFunctor& aFunctor) {
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|
void* result=nsnull;
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|
if(aNode) {
|
|
result = avlFirstThat(aNode->mLeft,aFunctor);
|
|
if (result) {
|
|
return result;
|
|
}
|
|
result = aFunctor(aNode->mValue);
|
|
if (result) {
|
|
return result;
|
|
}
|
|
result = avlFirstThat(aNode->mRight,aFunctor);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
*
|
|
* @update gess9/11/98
|
|
* @param
|
|
* @return
|
|
*/
|
|
void*
|
|
nsAVLTree::FirstThat(nsAVLNodeFunctor& aFunctor) const{
|
|
return ::avlFirstThat(mRoot,aFunctor);
|
|
}
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|
|