/*
 * $Id$
 *
 * Copyright (C) 2003-2015 JNode.org
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; If not, write to the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
package org.jnode.fs.hfsplus.tree;

import org.jnode.util.BigEndian;

public class NodeDescriptor {
    public static final int BT_LEAF_NODE = -1;
    public static final int BT_INDEX_NODE = 0;
    public static final int BT_HEADER_NODE = 1;
    public static final int BT_MAP_NODE = 2;

    /**
     * The size of the node descriptor.
     */
    public static final int BT_NODE_DESCRIPTOR_LENGTH = 14;

    /**
     * The number of the next node.
     */
    private long fLink;

    /**
     * The number of the previous node.
     */
    private long bLink;

    /**
     * The type of the node.
     */
    private int kind;

    /**
     * The depth of this node in the B-Tree.
     */
    private int height;

    /**
     * The number of records in this node.
     */
    private int numRecords;

    /**
     * Creates a new node descriptor.
     *
     * @param fLink
     * @param bLink
     * @param kind
     * @param height
     * @param numRecords
     */
    public NodeDescriptor(int fLink, int bLink, int kind, int height, int numRecords) {
        this.fLink = fLink;
        this.bLink = bLink;
        this.kind = kind;
        this.height = height;
        this.numRecords = numRecords;
    }

    /**
     * Creates node descriptor from existing data.
     *
     * @param src    byte array contains node descriptor data.
     * @param offset start of node descriptor data.
     */
    public NodeDescriptor(final byte[] src, int offset) {
        byte[] data = new byte[BT_NODE_DESCRIPTOR_LENGTH];
        System.arraycopy(src, offset, data, 0, BT_NODE_DESCRIPTOR_LENGTH);
        fLink = BigEndian.getUInt32(data, 0);
        bLink = BigEndian.getUInt32(data, 4);
        kind = BigEndian.getInt8(data, 8);
        height = BigEndian.getUInt8(data, 9);
        numRecords = BigEndian.getUInt16(data, 10);
    }

    /**
     * @return the descriptor rendered as bytes
     */
    public byte[] getBytes() {
        byte[] data = new byte[BT_NODE_DESCRIPTOR_LENGTH];
        BigEndian.setInt32(data, 0, (int) fLink);
        BigEndian.setInt32(data, 4, (int) bLink);
        BigEndian.setInt8(data, 8, kind);
        BigEndian.setInt8(data, 9, height);
        BigEndian.setInt16(data, 10, numRecords);
        return data;
    }

    public final String toString() {
        return String.format("nd[FLink:  %d BLink: %d Kind: %d height: %d #rec: %d]", getFLink(), getBLink(),
            getKind(), getHeight(), getNumRecords());
    }

    public long getFLink() {
        return fLink;
    }

    public long getBLink() {
        return bLink;
    }

    public int getKind() {
        return kind;
    }

    public int getHeight() {
        return height;
    }

    public int getNumRecords() {
        return numRecords;
    }

    public boolean isIndexNode() {
        return kind == NodeDescriptor.BT_INDEX_NODE;
    }

    public boolean isLeafNode() {
        return kind == NodeDescriptor.BT_LEAF_NODE;
    }

    public boolean isMapNode() {
        return kind == NodeDescriptor.BT_MAP_NODE;
    }

}