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810 lines
22 KiB
810 lines
22 KiB
//#pragma title( "TNode.cpp - List/Tree base classes" )
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/*
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Copyright (c) 1995-1998, Mission Critical Software, Inc. All rights reserved.
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===============================================================================
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Module - TNode.cpp
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System - Common
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Author - Tom Bernhardt
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Created - 1989-11-19
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Description - List/Tree base classes.
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TNode is a base class to define a collection element. It
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contains a left and right pointer to another TNode item and
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these may be organized as a double-linked linear list or
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binary tree in the collection classes that use TNode items.
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Central to its utility are member functions to convert between
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binary tree, sorted 2-way linear linked lists, and unsorted 2-way
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linked linear lists.
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Collection and enum classes
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TNodeList A simple collection of TNode elements.
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TNodeListSortable A TNodeList that is sortable by one or more compare functions.
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Conversion member functions for TNodeListSortable:
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The form of the list may be easily changed from binary tree to sorted list or
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vice versa. The following member functions support these transformations:
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ToSorted Converts the tree form into a sorted linear list form without
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need for comparisons; the order is preserved.
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SortedToTree Converts the sorted linear list form into a perfectly
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balanced binary tree without comparisons; the order is preserved.
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UnsortedToTree Converts the sorted linear list form into a binary tree
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that is not necesarily balanced. It uses the PCompare function
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to form the order of the tree. Thus if the list order closely
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matches the PCompare directed order, the resulting tree will be
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grossly unbalanced. This has a bearing on the performance and
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memory requirements of the ToSorted function which is recursive.
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So be careful, especially with large lists.
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Sort This resorts either a tree or list form according to the argument
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pCompare function pointer provided. Note the above admonition.
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In either form, exposed are also Insert and Remove member functions. The functions
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are wrappers for TreeInsert and SortedInsert function depending upon the current
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list type.
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Updates -
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1995-05-01 TPB Converted to C++ classes.
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===============================================================================
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*/
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#ifdef USE_STDAFX
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# include "stdafx.h"
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#else
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# include <windows.h>
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#endif
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#include <stdlib.h>
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#include <stdio.h>
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#include <malloc.h>
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#include "TNode.hpp"
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#include "common.hpp"
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#pragma page()
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//------------------------------------------------------------------------------
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// Warning: Must not pass top == NULL
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//------------------------------------------------------------------------------
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TNode * // ret-head of sorted list
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TNodeListSortable::TreeToSortedList(
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TNode * top ,// i/o-top of [sub]tree to squash
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TNode ** newhead ,// out-leftmost branch from tree
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TNode ** newtail // out-rightmost branch from tree
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)
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{
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TNode * temp; // temporary pointer placeholder
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if ( top->left == NULL )
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*newhead = top; // this is leftmost of parent node
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else
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{
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TreeToSortedList(top->left, newhead, &temp);
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top->left = temp; // left = tail of sub-list
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top->left->right = top;
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}
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if ( top->right == NULL )
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*newtail = top; // tree is rightmost of parent node
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else
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{
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TreeToSortedList(top->right, &temp, newtail);
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top->right = temp; // right = head of sub-list
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top->right->left = top;
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}
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return *newhead;
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}
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//------------------------------------------------------------------------------
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// converts sorted 2-linked list into balanced binary tree
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//------------------------------------------------------------------------------
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TNode * // ret-middle of list (head of Btree)
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TNodeListSortable::ListSortedToTree(
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TNode * top // i/o-top of [sub]list to tree-ify
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)
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{
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TNode * mid = top ,// middle of list
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* curr;
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int odd = 1;
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if ( top == NULL )
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return NULL;
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for ( curr = top; curr; curr = curr->right ) // find list middle
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{
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if ( odd ^= 1 )
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mid = mid->right;
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}
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if ( mid->left ) // split list around mid point
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{
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mid->left->right = NULL; // right terminate new sublist
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mid->left = ListSortedToTree(top); // recursive call to set left side
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}
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if ( mid->right )
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{
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mid->right->left = NULL; // left terminate new sublist
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mid->right = ListSortedToTree(mid->right);// recursive call to set right side
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}
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return mid;
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}
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#pragma page()
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TNode * // ret-new head of tree
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TNodeListSortable::UnsortedToTree()
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{
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TNode * treehead = NULL,
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* tree,
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* curr,
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* next;
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MCSASSERTSZ( !IsTree(), "TNodeListSortable::UnsortedToTree - list is already a tree" );
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if ( !IsTree() )
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{
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for ( curr = head; curr; curr = next )// insert each node into BinTree
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{
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next = curr->right; // save right pointer
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curr->right = curr->left = NULL; // break chains for insertion node
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if ( treehead == NULL )
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treehead = curr; // first node become BinTree head
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else
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{
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for ( tree = treehead; ; ) // iterative BinTree insert algorithm
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{
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if ( PCompare(curr, tree) <=0 )// if belongs left of current node
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if ( tree->left == NULL ) // if left tree empty
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{
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tree->left = curr; // insert here
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break; // and process right node
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}
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else // else
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tree = tree->left; // go down left side 1 level
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else // must be right side
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{
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if ( tree->right == NULL )
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{
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tree->right = curr;
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break;
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}
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else
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tree = tree->right;
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}
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}
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}
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}
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TypeSetTree();
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}
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return treehead;
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}
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#pragma page()
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//------------------------------------------------------------------------------
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// comparison function used for scrambling a sorted linked list
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//------------------------------------------------------------------------------
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TNodeCompare(ScrambledCompare)
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{
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return (rand() - RAND_MAX/2);
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}
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//------------------------------------------------------------------------------
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// converts sorted 2-linked list into a scrambled random binary tree
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//------------------------------------------------------------------------------
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void
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TNodeListSortable::SortedToScrambledTree()
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{
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MCSASSERTSZ( !IsTree(), "TNodeListSortable::SortedToScrambledTree - list is already a tree" );
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if ( !IsTree() )
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{
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TNodeCompare((*pOldCompare));
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pOldCompare = PCompare;
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CompareSet(ScrambledCompare);
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UnsortedToTree();
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CompareSet(pOldCompare);
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}
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}
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#pragma page()
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TNodeList::~TNodeList()
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{
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// _ASSERTE( (count == 0) && (head == NULL) );
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if ( (count == 0) && (head == NULL) )
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;
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else
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{
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//printf( "\aTNodeList destructor failure - list is not empty!\a\n" );
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}
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}
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void
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TNodeList::InsertTop(
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TNode * eIns // i/o-element to be inserted
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)
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{
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MCSVERIFY(this);
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MCSVERIFY(eIns);
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eIns->right = head;
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eIns->left = NULL;
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if ( head )
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head->left = eIns;
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else
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tail = eIns;
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head = eIns;
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count++;
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return;
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}
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void
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TNodeList::InsertBottom(
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TNode * eIns // i/o-element to be inserted
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)
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{
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MCSVERIFY(this);
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MCSVERIFY(eIns);
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eIns->right = NULL;
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eIns->left = tail;
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if ( tail )
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tail->right = eIns;
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else
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head = eIns;
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tail = eIns;
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count++;
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return;
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}
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void
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TNodeList::InsertAfter(
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TNode * eIns ,// i/o-element to be inserted
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TNode * eAft // i/o-element insert point
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)
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{
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TNode * eFwd; // element after inserted element
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MCSVERIFY(this);
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MCSVERIFY(eIns);
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if ( !eAft )
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InsertTop( eIns );
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else
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{
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eFwd = eAft->right;
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eIns->right = eFwd;
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eIns->left = eAft;
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if ( eFwd )
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eFwd->left = eIns;
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else
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tail = eIns;
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eAft->right = eIns;
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count++;
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}
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}
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void
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TNodeList::InsertBefore(
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TNode * eIns ,// i/o-element to be inserted
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TNode * eBef // i/o-element insert point
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)
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{
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TNode * eBwd; // element before inserted element
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MCSVERIFY(this);
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MCSVERIFY(eIns);
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if ( !eBef )
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InsertBottom( eIns );
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else
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{
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eBwd = eBef->left;
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eIns->right = eBef;
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eIns->left = eBwd;
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if ( eBwd )
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eBwd->right = eIns;
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else
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head = eIns;
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eBef->left = eIns;
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count++;
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}
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return;
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}
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void
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TNodeList::Remove(
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TNode const * t // i/o-new node to remove from list but not delete
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)
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{
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MCSVERIFY(this);
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MCSVERIFY(t);
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if ( t->left )
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t->left->right = t->right;
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else
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head = t->right;
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if ( t->right )
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t->right->left = t->left;
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else
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tail = t->left;
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count--;
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//Remove links to the list from t. We cant do this because
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// t is a const *
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//t->left = t->right = NULL;
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}
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void
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TNodeList::Reverse()
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{
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TNode * node;
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TNode * swap;
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MCSVERIFY(this);
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for ( node = head; node; node = node->left )
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{
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swap = node->left;
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node->left = node->right;
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node->right = swap;
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}
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swap = head;
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head = tail;
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tail = swap;
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}
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TNode *
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TNodeList::Find(
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TNodeCompareValue( (* Compare) ) ,// in -compares value in TNode to other value
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void const * findval
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) const
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{
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TNode * curr;
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MCSASSERT(this);
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for ( curr = head; curr; curr = curr->right )
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{
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if ( !Compare( curr, findval ) )
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break;
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}
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return curr;
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}
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BOOL // ret-TRUE if valid
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TNodeListSortable::CountTree(
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TNode * pCurrentTop ,// i/o-top of [sub]tree to count nodes
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DWORD * pCount // i/o-Number of nodes encountered in the tree
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)
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{
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if ( !pCurrentTop )
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return TRUE;
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(*pCount)++;
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if( (*pCount) > count )
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return FALSE;
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if(!CountTree(pCurrentTop->left,pCount))
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return FALSE;
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if(!CountTree(pCurrentTop->right,pCount))
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return FALSE;
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return TRUE;
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}
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BOOL // TRUE if Valid and FALSE if not
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TNodeListSortable::ValidateTree()
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{
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DWORD dwTempCount=0;
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DWORD bValid;
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MCSVERIFY(listType == TNodeTypeTree);
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bValid = CountTree(head,&dwTempCount);
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return bValid;
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}
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// Routine to validate the state of the list
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DWORD
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TNodeList::Validate(
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TNode ** pErrorNode
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)
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{
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DWORD dwError=0;
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DWORD nNodesVisited=0;
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TNode * pCurrentNode;
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DWORD dwNodeCount = Count();
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if(pErrorNode)
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*pErrorNode = NULL;
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#ifndef WIN16_VERSION
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try
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{
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#endif
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pCurrentNode = head;
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if ( pCurrentNode) // If the list is not empty
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{
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if ( pCurrentNode->left)
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{
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dwError = MCS_ListError_InvalidHead;
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}
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else
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{
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while ( pCurrentNode->right )
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{
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if(pCurrentNode->right->left != pCurrentNode)
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{
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dwError = MCS_ListError_InvalidPtr;
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if(pErrorNode)
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*pErrorNode = pCurrentNode->right;
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break;
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}
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nNodesVisited++;
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if ( nNodesVisited > dwNodeCount )
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{
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dwError = MCS_ListError_InvalidCount;
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break;
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}
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pCurrentNode = pCurrentNode->right;
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}
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if ( (!dwError) && (!pCurrentNode->right) )
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{
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if ( pCurrentNode != tail)
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{
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dwError = MCS_ListError_InvalidTail;
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if(pErrorNode)
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*pErrorNode = pCurrentNode->right;
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}
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}
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}
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}
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else // if the list is empty
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{
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if(dwNodeCount)
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{
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dwError = MCS_ListError_InvalidCount;
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}
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}
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#ifndef WIN16_VERSION
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}
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catch(...)
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{
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dwError = MCS_ListError_Exception;
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}
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#endif
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return dwError;
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}
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void
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TNodeListSortable::TreeRemove(
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TNode * item // i/o-node to remove from binary tree
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)
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{
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TNode ** prevNext = &head,
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* rep,
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* repLeft,
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* temp;
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int cmp;
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MCSVERIFY(listType == TNodeTypeTree);
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while ( *prevNext )
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{
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cmp = PCompare( item, *prevNext );
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if ( cmp < 0 )
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prevNext = &(*prevNext)->left;
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else if ( cmp > 0 )
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prevNext = &(*prevNext)->right;
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else
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{
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// we've found a matching 'name' (they compare equal)
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if ( *prevNext == item )
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{
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// we've found the address we're looking for
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if ( (*prevNext)->right )
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{
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rep = repLeft = (*prevNext)->right;
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for ( temp = rep->left; temp; temp = temp->left )
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repLeft = temp;
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repLeft->left = (*prevNext)->left;
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temp = *prevNext;
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*prevNext = rep;
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}
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else
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{
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temp = *prevNext;
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*prevNext = (*prevNext)->left; // simple case
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}
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// break removed nodes links to existing tree
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temp->left = temp->right = NULL;
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count--;
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break;
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}
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}
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}
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return;
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}
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// returns the insert point in a sorted list for a prospective node
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TNode * // ret-insert before point or NULL
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TNodeListSortable::SortedFindInsertBefore(
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TNode * item ,// i/o-node to insert into TNode
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BOOL * exists // out-TRUE if already exists
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)
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{
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int c;
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TNode * curr;
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*exists = FALSE;
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if ( !lastInsert )
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{
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if ( !head ) // if null head, empty list, return NULL
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return NULL;
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lastInsert = head;
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}
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c = PCompare(item, lastInsert);
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if ( c < 0 )
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lastInsert = head;
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for ( curr = lastInsert; curr; curr = curr->right )
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{
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c = PCompare(item, curr);
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if ( c <= 0 )
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if ( c == 0 )
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*exists = TRUE;
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else
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break;
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}
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return curr;
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}
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// inserts node into sorted linear list
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void
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TNodeListSortable::SortedInsert(
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TNode * item // i/o-node to insert into TNode
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)
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{
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BOOL exists;
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MCSVERIFY(listType != TNodeTypeTree);
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TNode * insertPoint = SortedFindInsertBefore(item, &exists);
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InsertBefore(item, insertPoint);
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lastInsert = item;
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}
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BOOL
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TNodeListSortable::SortedInsertIfNew(
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TNode * item // i/o-node to insert into TNode
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)
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{
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BOOL exists;
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TNode * insertPoint = SortedFindInsertBefore(item, &exists);
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if ( !exists )
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{
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InsertBefore(item, insertPoint);
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lastInsert = item;
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}
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return !exists;
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}
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|
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void
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TNodeListSortable::TreeInsert(
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TNode * item ,// i/o-node to insert into binary tree
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short * depth // out-tree/recursion depth of new item
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)
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{
|
|
TNode ** prevNext = &head;
|
|
int cmp;
|
|
|
|
MCSVERIFY(listType == TNodeTypeTree);
|
|
|
|
for ( *depth = 0; *prevNext; (*depth)++ )
|
|
{
|
|
cmp = PCompare( item, *prevNext );
|
|
if ( cmp <= 0 )
|
|
prevNext = &(*prevNext)->left;
|
|
else
|
|
prevNext = &(*prevNext)->right;
|
|
}
|
|
*prevNext = item;
|
|
item->left = item->right = NULL;
|
|
count++;
|
|
return;
|
|
}
|
|
|
|
|
|
TNode *
|
|
TNodeListSortable::TreeFind(
|
|
TNodeCompareValue( (* Compare) ) ,// in -compares value in TNode to other value
|
|
void const * findval
|
|
) const
|
|
{
|
|
TNode * curr = head;
|
|
int cmp;
|
|
|
|
while ( curr )
|
|
{
|
|
cmp = Compare( curr, findval );
|
|
if ( cmp > 0 )
|
|
curr = curr->left;
|
|
else if ( cmp < 0 )
|
|
curr = curr->right;
|
|
else // cmp == 0
|
|
break;
|
|
}
|
|
return curr;
|
|
}
|
|
|
|
|
|
TNode * // ret-TNode at pos n or NULL
|
|
TNodeListOrdEnum::Get(
|
|
long n // in -new position
|
|
)
|
|
{
|
|
long disCurr = n - nCurr, // distance to curr
|
|
disTop = n < (long)list->Count()/2 ? n : n - list->Count();
|
|
|
|
#ifdef WIN16_VERSION
|
|
long absDisTop = (disTop<0) ? -disTop : disTop;
|
|
long absDisCurr = (disCurr<0) ? -disCurr : disCurr;
|
|
if ( absDisTop < absDisCurr )
|
|
#else
|
|
if ( abs(disTop) < abs(disCurr) )
|
|
#endif
|
|
{
|
|
Top();
|
|
disCurr = disTop;
|
|
}
|
|
if ( disCurr < 0 )
|
|
for ( Prev(); n < nCurr && Prev(); );
|
|
else
|
|
for ( ; n > nCurr && Next(); );
|
|
|
|
return curr;
|
|
}
|
|
|
|
// returns the first node of the tree
|
|
TNode *
|
|
TNodeTreeEnum::First()
|
|
{
|
|
stackPos = stackBase;
|
|
if ( top )
|
|
Push(top);
|
|
return Next();
|
|
}
|
|
|
|
// Returns the tree node logically following the value per the sort organization
|
|
// specified by Compare, and sets up the enumeration to continue from that point.
|
|
TNode *
|
|
TNodeTreeEnum::FirstAfter(
|
|
TNodeCompareValue( (* Compare) ) ,// in -compares value in TNode to other value
|
|
void const * findVal // in -findVal to position after
|
|
)
|
|
{
|
|
TNode * tn;
|
|
int cmp;
|
|
|
|
stackPos = stackBase;
|
|
for ( tn = top; tn; )
|
|
{
|
|
Push(tn);
|
|
cmp = Compare( tn, findVal );
|
|
if ( cmp < 0 )
|
|
{
|
|
stackPos->state = Sright;
|
|
if ( tn->right )
|
|
tn = tn->right;
|
|
else
|
|
return Next();
|
|
}
|
|
else if ( cmp > 0 )
|
|
{
|
|
stackPos->state = Sleft;
|
|
if ( tn->left )
|
|
tn = tn->left;
|
|
else
|
|
{
|
|
stackPos->state = Sused;
|
|
return tn;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
stackPos->state = Sused;
|
|
return Next();
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
|
|
// returns the Next logical node of the tree ending with NULL when complete
|
|
TNode *
|
|
TNodeTreeEnum::Next()
|
|
{
|
|
for ( ;; )
|
|
{
|
|
switch ( stackPos->state )
|
|
{
|
|
case Snone: // we've done nothing here
|
|
stackPos->state = Sleft;
|
|
if ( stackPos->save->left )
|
|
Push(stackPos->save->left);
|
|
break;
|
|
case Sleft: // we've gone left and are back
|
|
stackPos->state = Sused;
|
|
return stackPos->save;
|
|
case Sused: // we've used the node
|
|
stackPos->state = Sright;
|
|
if ( stackPos->save->right )
|
|
Push(stackPos->save->right);// process right side of branch
|
|
break;
|
|
case Sright: // we've gone right and are back
|
|
if ( !Pop() )
|
|
return NULL;
|
|
break;
|
|
case SComplete:
|
|
return NULL;
|
|
break; // Do we need this?
|
|
default: // bad error
|
|
MCSASSERT(FALSE);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
return NULL; // can't get here
|
|
}
|
|
|
|
// Returns the address of the forward (left/right) pointer where the find node
|
|
// already exists or would be inserted. If the singly deferenced result is not
|
|
// null, the node's key value already exists in the tree.
|
|
// If, after obtaining the insertion point, you want to insert the node, just
|
|
// assign its address to the singly deferenced return value. The following inserts
|
|
// the node "f" if it is not alread in the tree:
|
|
// TNode **r = tree.TreeFindInsert(f);
|
|
// if ( !*r )
|
|
// *r = f;
|
|
TNode ** // ret-pointer forward pointer to find
|
|
TNodeListSortable::TreeFindInsert(
|
|
TNode const * find ,// in -node to find
|
|
short * depth // out-tree depth of insertion point
|
|
)
|
|
{
|
|
TNode ** prevNext = &head;
|
|
int cmp;
|
|
|
|
for ( *depth = 0; *prevNext; (*depth)++ )
|
|
{
|
|
cmp = PCompare( find, *prevNext );
|
|
if ( cmp < 0 )
|
|
prevNext = &(*prevNext)->left;
|
|
else if ( cmp > 0 )
|
|
prevNext = &(*prevNext)->right;
|
|
else
|
|
break;
|
|
}
|
|
|
|
return prevNext;
|
|
}
|
|
|
|
// TNode.cpp - end of file
|