insert.c File Reference

#include "tree.h"

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Functions
void	treeRotateLeft (Tree *, Tree)
void	treeRotateRight (Tree *, Tree)
void *	treeInsert (Tree *this, const void *search, TreeComp comp)

Detailed Description

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/.

Definition in file insert.c.

Function Documentation

void* treeInsert	(	Tree *	this,
		const void *	search,
		TreeComp	comp
	)

Definition at line 29 of file insert.c.

References comp(), rbBlack, rbRed, TREE_GRANDPARENT, TREE_LEFT, TREE_PARENT, TREE_RIGHT, TREE_UNCLE, treeRotateLeft(), and treeRotateRight().

Referenced by hashAdd(), and main().

{
    Tree node     = *this;
    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 = new(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 != TREE_LEFT(node)) {
                    node = TREE_LEFT(node);
                    continue;
                } else {
                    break;
                }
            }

            if (0 > comparison) {
                if (NULL != TREE_RIGHT(node)) {
                    node = 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 = new(Tree, search);
            TREE_LEFT(node)->parent = node;
            node = new_node = TREE_LEFT(node);
        } else {
            node->right = new(Tree, search);
            TREE_RIGHT(node)->parent = node;
            node = new_node = 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 == TREE_PARENT(node)) {
            node->color = rbBlack;
            break;
        }

        // case 2
        if (rbBlack == TREE_PARENT(node)->color) {
            break;
        }

        // case 3
        if (NULL != TREE_UNCLE(node) && rbRed == TREE_UNCLE(node)->color) {
            TREE_PARENT(node)->color      = rbBlack;
            TREE_UNCLE(node)->color       = rbBlack;
            TREE_GRANDPARENT(node)->color = rbRed;

            node = TREE_GRANDPARENT(node);
            continue;
        }

        // case 4
        if (node == TREE_PARENT(node)->right
                && TREE_PARENT(node) == TREE_GRANDPARENT(node)->left) {

            //TREE_ROTATE_LEFT(this, TREE_PARENT(node));
            treeRotateLeft(this, TREE_PARENT(node));
            node = TREE_LEFT(node);

        } else if (node == TREE_PARENT(node)->left
                && TREE_PARENT(node) == TREE_GRANDPARENT(node)->right) {

            //TREE_ROTATE_RIGHT(this, TREE_PARENT(node));
            treeRotateRight(this, TREE_PARENT(node));
            node = TREE_RIGHT(node);

        }

        // case 5
        TREE_PARENT(node)->color      = rbBlack;
        TREE_GRANDPARENT(node)->color = rbRed;

        if (node == TREE_PARENT(node)->left) {
            //TREE_ROTATE_RIGHT(this, TREE_GRANDPARENT(node));
            treeRotateRight(this, TREE_GRANDPARENT(node));
        } else {
            //TREE_ROTATE_LEFT(this, TREE_GRANDPARENT(node));
            treeRotateLeft(this, TREE_GRANDPARENT(node));
        }

        break;
    }

    return new_node->data;
}

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void treeRotateLeft	(	Tree *	,
		Tree
	)

Definition at line 26 of file rotateLeft.c.

References TREE_PARENT, TREE_RIGHT, and TREE_RIGHT_LEFT.

Referenced by treeInsert().

{
    Tree rightChild = TREE_RIGHT(node);
    Tree rcLeftSub  = TREE_RIGHT_LEFT(node);

    rightChild->left   = node;
    rightChild->parent = TREE_PARENT(node);
    node->right        = rcLeftSub;
    if (NULL != rcLeftSub) {
        rcLeftSub->parent  = node;
    }   

    if (NULL != TREE_PARENT(node)) {
        if (TREE_PARENT(node)->left == node) {
            TREE_PARENT(node)->left = rightChild;
        } else {
            TREE_PARENT(node)->right = rightChild;
        }   
    } else {
        *this = rightChild;
    }   

    node->parent = rightChild;
}

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void treeRotateRight	(	Tree *	,
		Tree
	)

Definition at line 26 of file rotateRight.c.

References TREE_LEFT, TREE_LEFT_RIGHT, and TREE_PARENT.

Referenced by treeInsert().

{
    Tree leftChild  = TREE_LEFT(node);
    Tree lcRightSub = TREE_LEFT_RIGHT(node);

    leftChild->right   = node;
    leftChild->parent  = TREE_PARENT(node);
    node->left         = lcRightSub;
    if (NULL != lcRightSub) {
        lcRightSub->parent = node;
    }   

    if (NULL != TREE_PARENT(node)) {
        if (TREE_PARENT(node)->left == node) {
            TREE_PARENT(node)->left = leftChild;
        } else {
            TREE_PARENT(node)->right = leftChild;
        }   
    } else {
        *this = leftChild;
    }   

    node->parent = leftChild;
}

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