/* $Id: avl_GetBestFit.cpp.h 83575 2013-02-04 14:27:54Z fmehnert $ */
/** @file
 * kAVLGetBestFit - Get Best Fit routine for AVL trees.
 *                  Intended specially on heaps. The tree should allow duplicate keys.
 *
 */

/*
 * Copyright (C) 1999-2012 knut st. osmundsen (bird-src-spam@anduin.net)
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */

#ifndef _kAVLGetBestFit_h_
#define _kAVLGetBestFit_h_

/**
 * Finds the best fitting node in the tree for the given Key value.
 * @returns   Pointer to the best fitting node found.
 * @param     ppTree  Pointer to Pointer to the tree root node.
 * @param     Key     The Key of which is to be found a best fitting match for..
 * @param     fAbove  TRUE:  Returned node is have the closest key to Key from above.
 *                    FALSE: Returned node is have the closest key to Key from below.
 * @sketch    The best fitting node is always located in the searchpath above you.
 *            >= (above): The node where you last turned left.
 *            <= (below): the node where you last turned right.
 */
KAVL_DECL(PKAVLNODECORE) KAVL_FN(GetBestFit) (PPKAVLNODECORE ppTree,
					      KAVLKEY Key, bool fAbove)
{
	register PKAVLNODECORE pNode = KAVL_GET_POINTER_NULL(ppTree);
	if (pNode) {
		PKAVLNODECORE pNodeLast = NULL;
		if (fAbove) {	/* pNode->Key >= Key */
			while (KAVL_NE(pNode->Key, Key)) {
				if (KAVL_G(pNode->Key, Key)) {
					if (pNode->pLeft != KAVL_NULL) {
						pNodeLast = pNode;
						pNode =
						    KAVL_GET_POINTER(&pNode->
								     pLeft);
					} else
						return pNode;
				} else {
					if (pNode->pRight != KAVL_NULL)
						pNode =
						    KAVL_GET_POINTER(&pNode->
								     pRight);
					else
						return pNodeLast;
				}
			}
		} else {	/* pNode->Key <= Key */
			while (KAVL_NE(pNode->Key, Key)) {
				if (KAVL_G(pNode->Key, Key)) {
					if (pNode->pLeft != KAVL_NULL)
						pNode =
						    KAVL_GET_POINTER(&pNode->
								     pLeft);
					else
						return pNodeLast;
				} else {
					if (pNode->pRight != KAVL_NULL) {
						pNodeLast = pNode;
						pNode =
						    KAVL_GET_POINTER(&pNode->
								     pRight);
					} else
						return pNode;
				}
			}
		}
	}

	/* perfect match or nothing. */
	return pNode;
}

#endif
