insert.c
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/**
* \file
*
* \author Georg Hopp
*
* \copyright
* Copyright © 2012 Georg Hopp
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "trbase.h"
#include "tr/tree.h"
void TR_treeRotateLeft(TR_Tree *, TR_Tree);
void TR_treeRotateRight(TR_Tree *, TR_Tree);
void *
TR_treeInsert(TR_Tree * this, const void * search, TR_TreeComp comp)
{
TR_Tree node = *this;
TR_Tree new_node = NULL;
/*
* insert the node or return the one in tree if comparison
* succeeds.
*/
if (NULL == node) {
/*
* if the root is NULL we simple add the element and set
* node to it.
*/
*this = node = new_node = TR_new(TR_Tree, search);
} else {
/*
* first search for it and if its found return the data
* and we are done...
*/
int comparison;
while (NULL != node) {
comparison = comp(node->data, search);
if (0 < comparison) {
if (NULL != TR_TREE_LEFT(node)) {
node = TR_TREE_LEFT(node);
continue;
} else {
break;
}
}
if (0 > comparison) {
if (NULL != TR_TREE_RIGHT(node)) {
node = TR_TREE_RIGHT(node);
continue;
} else {
break;
}
}
if (0 == comparison) {
return node->data;
}
}
/*
* as we have not found it now add a new element.
*/
if (0 < comparison) {
node->left = TR_new(TR_Tree, search);
TR_TREE_LEFT(node)->parent = node;
node = new_node = TR_TREE_LEFT(node);
} else {
node->right = TR_new(TR_Tree, search);
TR_TREE_RIGHT(node)->parent = node;
node = new_node = TR_TREE_RIGHT(node);
}
}
/*
* we expect node not to be NULL and pointing to our
* new node at this point...now rabalance the tree
*/
while (1) {
// case 1
if (NULL == TR_TREE_PARENT(node)) {
node->color = rbBlack;
break;
}
// case 2
if (rbBlack == TR_TREE_PARENT(node)->color) {
break;
}
// case 3
if (NULL != TR_TREE_UNCLE(node) && rbRed == TR_TREE_UNCLE(node)->color) {
TR_TREE_PARENT(node)->color = rbBlack;
TR_TREE_UNCLE(node)->color = rbBlack;
TR_TREE_GRANDPARENT(node)->color = rbRed;
node = TR_TREE_GRANDPARENT(node);
continue;
}
// case 4
if (node == TR_TREE_PARENT(node)->right
&& TR_TREE_PARENT(node) == TR_TREE_GRANDPARENT(node)->left) {
//TREE_ROTATE_LEFT(this, TREE_PARENT(node));
TR_treeRotateLeft(this, TR_TREE_PARENT(node));
node = TR_TREE_LEFT(node);
} else if (node == TR_TREE_PARENT(node)->left
&& TR_TREE_PARENT(node) == TR_TREE_GRANDPARENT(node)->right) {
//TREE_ROTATE_RIGHT(this, TREE_PARENT(node));
TR_treeRotateRight(this, TR_TREE_PARENT(node));
node = TR_TREE_RIGHT(node);
}
// case 5
TR_TREE_PARENT(node)->color = rbBlack;
TR_TREE_GRANDPARENT(node)->color = rbRed;
if (node == TR_TREE_PARENT(node)->left) {
//TREE_ROTATE_RIGHT(this, TREE_GRANDPARENT(node));
TR_treeRotateRight(this, TR_TREE_GRANDPARENT(node));
} else {
//TREE_ROTATE_LEFT(this, TREE_GRANDPARENT(node));
TR_treeRotateLeft(this, TR_TREE_GRANDPARENT(node));
}
break;
}
return new_node->data;
}
// vim: set ts=4 sw=4: