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116 lines
2.5 KiB
116 lines
2.5 KiB
/**
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* \file
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*
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* \author Georg Hopp
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*
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* \copyright
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* Copyright © 2012 Georg Hopp
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "trbase.h"
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#include "tr/tree.h"
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void *
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TR_treeDelete(TR_Tree * this, const void * search, TR_TreeComp comp)
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{
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TR_Tree node = *this;
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TR_Tree del_node;
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int found;
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void * data;
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TR_TREE_FIND(node, search, found, comp);
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/*
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* nothing was found...return NULL to indicate this.
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*/
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if (found != 0) {
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return NULL;
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}
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/*
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* we found an element, store its data pointer as we are
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* up to delete it.
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*/
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data = node->data;
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/*
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* now remove the element.
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*/
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/*
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* if we have two children replace data with the one from
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* out inOrderSuccessor and remove the inOrderSuccessor.
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*/
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if (NULL != TR_TREE_LEFT(node) && NULL != TR_TREE_RIGHT(node)) {
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TR_Tree successor;
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TR_TREE_INORDER_SUCC(node, successor);
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node->data = successor->data;
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node = successor;
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}
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{
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TR_Tree child = TR_TREE_CHILD(node);
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/*
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* if we still have one child replace ourself with it.
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*/
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TR_TREE_REPLACE_NODE(this, node, child);
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/*
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* and finally delete the node...and prepare ourselfs
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* for rebalancing.
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*/
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if (rbBlack == node->color) {
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if (NULL != child && rbRed == child->color) {
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child->color = rbBlack;
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TR_delete(node);
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return data;
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} else {
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del_node = node;
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if (NULL != child) {
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node = child;
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} else {
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node->color = rbBlack;
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node->left = NULL;
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node->right = NULL;
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}
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}
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} else {
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TR_delete(node);
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return data;
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}
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}
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/*
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* now comes rebalancing...note that if we came to this point
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* the node is still not deleted.
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* This is because I am not sure if it is needed during the
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* rebalancing process...(this does not make much sense, but
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* to be honest I don't know now.)
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*/
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{
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TR_Tree sibling = TR_TREE_SIBLING(node);
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TR_TREE_BALANCE_DELETE(this, node, sibling);
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}
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TR_delete(del_node);
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return data;
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}
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// vim: set ts=4 sw=4:
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