/*
 * Copyright (C) 2010 Timo Kokkonen <kaapeli@itanic.dy.fi>
 *
 * 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 2 of the License.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <stdlib.h>

#include "bintree.h"

/*
 * bintree_add - Add to tree
 *
 * Adds a node to a sorted tree. If the new node is already found from
 * the tree, the existing node is returned and the new node is not
 * added. If new node is not found, the new one is added and the tree
 * is kept sorted.
 */
struct bintree *bintree_add(struct bintree *tree, struct bintree *new,
			struct bintree_ops *ops)
{
	int ret;

	if (tree == NULL)
		return new;

	ret = ops->compare(tree, new);
	if (ret < 0) {
		if (tree->left)
			return bintree_add(tree->left, new, ops);
		tree->left = new;
		return new;
	}

	if (ret > 0) {
		if (tree->right)
			return bintree_add(tree->right, new, ops);
		tree->right = new;
		return new;
	}

	return tree;
}

/*
 * bintree_find - Find a node from a tree.
 *
 * If node is found, pointer to the node is returned. If no node is
 * found, null is returned.
 */
struct bintree *bintree_find(struct bintree *tree, struct bintree *new,
			struct bintree_ops *ops)
{
	int ret;

	if (tree == NULL)
		return NULL;

	ret = ops->compare(tree, new);
	if (ret < 0) {
		if (tree->left)
			return bintree_find(tree->left, new, ops);

		return NULL;
	}

	if (ret > 0) {
		if (tree->right)
			return bintree_find(tree->right, new, ops);

		return NULL;
	}

	return tree;
}

/*
 * bintree_walk - walk through a binary tree from left to right
 *
 * Returns the number of nodes in the tree
 */
int bintree_walk(struct bintree *tree, struct bintree_ops *ops)
{
	int count = 0;

	if (tree->left)
		count += bintree_walk(tree->left, ops);

	if (ops->callback)
		ops->callback(tree, ops);

	count++;

	if (tree->right)
		count += bintree_walk(tree->right, ops);

	return count;
}