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/**
 * eobjects.org MetaModel
 * Copyright (C) 2010 eobjects.org
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */

package org.xBaseJ.indexes;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import org.xBaseJ.DBF;
import org.xBaseJ.DbaseUtils;
import org.xBaseJ.xBaseJException;

/**
 * This class is courtesy of the xBaseJ project: http://xbasej.sourceforge.net/
 * 
 * Copyright 1997-2007 - American Coders, LTD - Raleigh NC USA
 * 
 *  * American Coders, Ltd
 * P. O. Box 97462
 * Raleigh, NC  27615  USA
 * 1-919-846-2014
 * http://www.americancoders.com
 * 
 * 
 * @author Joe McVerry, American Coders Ltd.
 */
public class MNode extends Node {
	int prev_page = 0;
	MDXFile mfile;

	public MNode(MDXFile file, int keys_in, int key_size, char keyType, int rn,
			boolean iBranch) {
		super(file.getRandomAccessFile(), keys_in, key_size, keyType, rn, iBranch);
		mfile = file;
	}

	public void read() throws IOException {
		int i, j, k;
		long longrecn = record_number;
		nfile.seek(longrecn * 512);
		keys_in_this_Node = DbaseUtils.x86(nfile.readInt());
		prev_page = DbaseUtils.x86(nfile.readInt());
		if (prev_page == 0)
			branch = false;
		else
			branch = true;

		byte b[] = new byte[12];
		for (i = 0; i < keys_in_a_Node; i++) {
			key_record_number[i] = DbaseUtils.x86(nfile.readInt());

			if (keyType == 'F') {
				nfile.read(b);
				if (i < keys_in_this_Node)
					key_expression[i] = new NodeKey(new NodeFloat(b));
				else
					key_expression[i] = new NodeKey(new NodeFloat(0.0));
			} else if (keyType == 'N') {
				key_expression[i] = new NodeKey(new Double(Double
						.longBitsToDouble(nfile.readLong())));
			} else {
				nfile.readFully(key_buffer, 0, key_expression_size);
				for (k = 0; k < key_expression_size && key_buffer[k] != 0; k++)
					;
				try {
					key_expression[i] = new NodeKey(new String(key_buffer, 0,
							k, DBF.encodedType));
				} catch (UnsupportedEncodingException UEE) {
					key_expression[i] = new NodeKey(
							new String(key_buffer, 0, k));
				}
			}

			j = key_expression_size % 4;
			if (j > 0)
				j = 4 - j;
			for (k = 0; k < j; k++)
				nfile.readByte();
		} // for i

		key_record_number[i] = DbaseUtils.x86(nfile.readInt());

		if (key_record_number[keys_in_this_Node] > 0)
			branch = true;
		else
			branch = false;

	}

	public void write() throws IOException, xBaseJException {
		int i, j, k, ll;
		long longrecn = record_number;
		nfile.seek(longrecn * 512);
		ll = mfile.getAnchor().get_blockbytes();

		nfile.writeInt(DbaseUtils.x86(keys_in_this_Node));
		ll -= 4; // sizeof(int)
		nfile.writeInt(DbaseUtils.x86(prev_page));
		ll -= 4; // sizeof(int)
		for (i = 0; i < keys_in_a_Node && key_expression[i] != null; i++) {
			if (key_expression[i] == null)
				throw new xBaseJException("Missing Node Key expression at " + i);
			if ((branch && (i <= keys_in_this_Node))
					|| (!branch && (i < keys_in_this_Node)))
				nfile.writeInt(DbaseUtils.x86(key_record_number[i]));
			else
				nfile.writeInt(0);
			ll -= 4;
			j = 0;
			ll -= key_expression_size;
			if (key_expression[i].getType() == 'F') {
				nfile.write(key_expression[i].toNodeFloat().getValue());
			} else if (key_expression[i].getType() == 'N') {
				double d = key_expression[i].toDouble();
				nfile.writeLong(Double.doubleToLongBits(d));
			} else {
				int x;
				byte bytebuffer[];
				try {
					bytebuffer = key_expression[i].toString().getBytes(
							DBF.encodedType);
				} catch (UnsupportedEncodingException UEE) {
					bytebuffer = key_expression[i].toString().getBytes();
				}
				for (x = 0; x < bytebuffer.length; x++)
					key_buffer[x] = bytebuffer[x];
				for (; x < key_expression_size; x++)
					key_buffer[x] = 0;
				nfile.write(key_buffer, 0, key_expression_size);
				j = key_expression_size % 4;
				if (j > 0)
					j = 4 - j;
			}
			key_buffer[0] = 0;
			for (k = 0; k < j; k++)
				nfile.write(key_buffer[0]);
			ll -= j; // sizeof(ints) and full key length to its 4 byte alignment
		} // for i

		if (branch)
			nfile.writeInt(DbaseUtils.x86(key_record_number[i]));
		else
			nfile.writeInt(0);
		ll -= 4; // sizeof(int)
		// a Node is 512 bytes long;
		if (ll > 0) {
			byte temp[] = new byte[ll];
			nfile.write(temp, 0, ll);
		}

	}

	public void set_lower_level(int level) {
		if (branch) {
			key_record_number[pos] = level;
		}
	}

	public int get_lower_level() {
		if (branch)
			return key_record_number[pos];
		else
			return 0;

	}

	public int get_prev_page() {
		return prev_page;
	}

	public void set_prev_page(int pp) {
		prev_page = pp;
	}

}