/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2004-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.index.quadtree.fs;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.charset.Charset;
import java.util.logging.Logger;
import org.geotools.index.quadtree.StoreException;
/**
* DOCUMENT ME!
*
* @author Tommaso Nolli
* @source $URL:
* http://svn.geotools.org/geotools/trunk/gt/modules/plugin/shapefile/src/main/java/org/geotools/index/quadtree/fs/IndexHeader.java $
*/
public class IndexHeader {
public static final byte LSB_ORDER = -1;
public static final byte MSB_ORDER = -2;
public static final byte NATIVE_ORDER = 0;
public static final byte NEW_LSB_ORDER = 1;
public static final byte NEW_MSB_ORDER = 2;
private static final String SIGNATURE = "SQT";
private static final byte VERSION = 1;
private static final byte[] RESERVED = { 0, 0, 0 };
private static final Logger LOGGER = org.geotools.util.logging.Logging
.getLogger("org.geotools.index.quadtree");
private byte byteOrder;
public IndexHeader(byte byteOrder) {
this.byteOrder = byteOrder;
}
/**
* DOCUMENT ME!
*
* @param channel
*
* @throws IOException
* @throws StoreException
*/
public IndexHeader(ReadableByteChannel channel) throws IOException,
StoreException {
ByteBuffer buf = ByteBuffer.allocate(8);
channel.read(buf);
buf.flip();
byte[] tmp = new byte[3];
buf.get(tmp);
String s = new String(tmp, "US-ASCII");
if (!s.equals(SIGNATURE)) {
// Old file format
LOGGER.warning("Old qix file format; this file format "
+ "is deprecated; It is strongly recommended "
+ "to regenerate it in new format.");
buf.position(0);
tmp = buf.array();
boolean lsb;
if ((tmp[4] == 0) && (tmp[5] == 0) && (tmp[6] == 0)
&& (tmp[7] == 0)) {
lsb = !((tmp[0] == 0) && (tmp[1] == 0));
} else {
lsb = !((tmp[4] == 0) && (tmp[5] == 0));
}
this.byteOrder = lsb ? LSB_ORDER : MSB_ORDER;
} else {
this.byteOrder = buf.get();
}
}
public void writeTo(ByteBuffer buf) {
Charset charSet = Charset.forName("US-ASCII");
ByteBuffer tmp = charSet.encode(SIGNATURE);
tmp.position(0);
buf.put(tmp);
buf.put(this.byteOrder);
buf.put(VERSION);
buf.put(RESERVED);
}
/**
* DOCUMENT ME!
*
* @return Returns the byteOrder.
*/
public byte getByteOrder() {
return this.byteOrder;
}
}