/*
 * For work developed by the HSQL Development Group:
 *
 * Copyright (c) 2001-2019, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 *
 * For work originally developed by the Hypersonic SQL Group:
 *
 * Copyright (c) 1995-2000, The Hypersonic SQL Group.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the Hypersonic SQL Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * on behalf of the Hypersonic SQL Group.
 */


package org.hsqldb.index;

import org.hsqldb.Row;
import org.hsqldb.RowAVL;
import org.hsqldb.RowAVLDisk;
import org.hsqldb.lib.LongLookup;
import org.hsqldb.persist.CachedObject;
import org.hsqldb.persist.PersistentStore;
import org.hsqldb.rowio.RowOutputInterface;
import org.hsqldb.rowio.RowInputInterface;

// fredt@users 20020221 - patch 513005 by sqlbob@users (RMP)
// fredt@users 20020920 - path 1.7.1 - refactoring to cut memory footprint
// fredt@users 20021205 - path 1.7.2 - enhancements
// fredt@users 20021215 - doc 1.7.2 - javadoc comments

 The parent for all AVL node implementations. Subclasses of Node vary
 in the way they hold
 references to other Nodes in the AVL tree, or to their Row data.

 nNext links the Node objects belonging to different indexes for each
 table row. It is used solely by Row to locate the node belonging to a
 particular index.

 New class derived from Hypersonic SQL code and enhanced in HSQLDB. 

Author:
Fred Toussi (fredt@users dot sourceforge dot net), Thomas Mueller (Hypersonic SQL Group)
Version:
2.3.3
Since:
Hypersonic SQL/**
 *  The parent for all AVL node implementations. Subclasses of Node vary
 *  in the way they hold
 *  references to other Nodes in the AVL tree, or to their Row data.<br>
 *
 *  nNext links the Node objects belonging to different indexes for each
 *  table row. It is used solely by Row to locate the node belonging to a
 *  particular index.<br>
 *
 *  New class derived from Hypersonic SQL code and enhanced in HSQLDB. <p>
 *
 * @author Fred Toussi (fredt@users dot sourceforge dot net)
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @version 2.3.3
 * @since Hypersonic SQL
 */
public class NodeAVL implements CachedObject {

    static final int NO_POS = RowAVLDisk.NO_POS;
    public int       iBalance;
    public NodeAVL   nNext;    // node of next index (nNext==null || nNext.iId=iId+1)

    //
    protected NodeAVL   nLeft;
    protected NodeAVL   nRight;
    protected NodeAVL   nParent;
    protected final Row row;

    NodeAVL() {
        row = null;
    }

    public NodeAVL(Row r) {
        row = r;
    }

    public void delete() {
        iBalance = 0;
        nLeft    = nRight = nParent = null;
    }

    NodeAVL getLeft(PersistentStore store) {
        return nLeft;
    }

    NodeAVL setLeft(PersistentStore persistentStore, NodeAVL n) {

        nLeft = n;

        return this;
    }

    public int getBalance(PersistentStore store) {
        return iBalance;
    }

    boolean isLeft(PersistentStore store, NodeAVL node) {
        return nLeft == node;
    }

    boolean isRight(PersistentStore store, NodeAVL node) {
        return nRight == node;
    }

    NodeAVL getRight(PersistentStore persistentStore) {
        return nRight;
    }

    NodeAVL setRight(PersistentStore persistentStore, NodeAVL n) {

        nRight = n;

        return this;
    }

    NodeAVL getParent(PersistentStore store) {
        return nParent;
    }

    boolean isRoot(PersistentStore store) {
        return nParent == null;
    }

    NodeAVL setParent(PersistentStore persistentStore, NodeAVL n) {

        nParent = n;

        return this;
    }

    public NodeAVL setBalance(PersistentStore store, int b) {

        iBalance = b;

        return this;
    }

    boolean isFromLeft(PersistentStore store) {

        if (nParent == null) {
            return true;
        }

        return this == nParent.nLeft;
    }

    public NodeAVL child(PersistentStore store, boolean isleft) {
        return isleft ? getLeft(store)
                      : getRight(store);
    }

    public NodeAVL set(PersistentStore store, boolean isLeft, NodeAVL n) {

        if (isLeft) {
            nLeft = n;
        } else {
            nRight = n;
        }

        if (n != null) {
            n.nParent = this;
        }

        return this;
    }

    public void replace(PersistentStore store, Index index, NodeAVL n) {

        if (nParent == null) {
            if (n != null) {
                n = n.setParent(store, null);
            }

            store.setAccessor(index, n);
        } else {
            nParent.set(store, isFromLeft(store), n);
        }
    }

    boolean equals(NodeAVL n) {
        return n == this;
    }

    public void setInMemory(boolean in) {}

    public int getDefaultCapacity() {
        return 0;
    }

    public void read(RowInputInterface in) {}

    public void write(RowOutputInterface out) {}

    public void write(RowOutputInterface out, LongLookup lookup) {}

    public long getPos() {
        return 0;
    }

    public RowAVL getRow(PersistentStore store) {
        return (RowAVL) row;
    }

    protected Object[] getData(PersistentStore store) {
        return row.getData();
    }

    public void updateAccessCount(int count) {}

    public int getAccessCount() {
        return 0;
    }

    public void setStorageSize(int size) {}

    public int getStorageSize() {
        return 0;
    }

    final public boolean isInvariable() {
        return false;
    }

    final public boolean isBlock() {
        return false;
    }

    public void setPos(long pos) {}

    public boolean isNew() {
        return false;
    }

    public boolean hasChanged() {
        return false;
    }

    public void setChanged(boolean flag) {}

    public boolean isKeepInMemory() {
        return false;
    }

    public boolean keepInMemory(boolean keep) {
        return true;
    }

    public boolean isInMemory() {
        return false;
    }

    public void restore() {}

    public void destroy() {}

    public int getRealSize(RowOutputInterface out) {
        return 0;
    }

    public boolean isMemory() {
        return true;
    }
}