ShapefileHeader.java

/**
 * H2GIS is a library that brings spatial support to the H2 Database Engine
 * <http://www.h2database.com>. H2GIS is developed by CNRS
 * <http://www.cnrs.fr/>.
 *
 * This code is part of the H2GIS project. H2GIS 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 3.0 of the License.
 *
 * H2GIS 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 <http://www.gnu.org/licenses/>.
 *
 *
 * For more information, please consult: <http://www.h2gis.org/>
 * or contact directly: info_at_h2gis.org
 */

package org.h2gis.functions.io.shp.internal;

import org.h2gis.functions.io.utility.WriteBufferManager;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
 *
 * @author jamesm
 * @author Ian Schneider
 * @source $URL:
 *         http://svn.geotools.org/geotools/tags/2.3.1/plugin/shapefile/src/org/geotools/data/shapefile/shp/ShapefileHeader.java $
 */
public class ShapefileHeader {
        
	public static final int MAGIC = 9994;

	public static final int VERSION = 1000;

	private int fileCode = -1;

	private int fileLength = -1;

	private int version = -1;

	private ShapeType shapeType = ShapeType.UNDEFINED;

	private double minX;

	private double maxX;

	private double minY;

	private double maxY;

	private void checkMagic() throws IOException {
		if (fileCode != MAGIC) {
			throw new IOException("Wrong magic number, expected "
					+ MAGIC + ", got " + fileCode);
		}
	}

	private void checkVersion() throws IOException {
		if (version != VERSION) {
            throw new IOException("Wrong version, expected " + MAGIC
					+ ", got " + version);
		}
	}

	public void read(ByteBuffer file)
			throws IOException {
		file.order(ByteOrder.BIG_ENDIAN);
		fileCode = file.getInt();

		checkMagic();

		// skip 5 ints...
		file.position(file.position() + 20);

		fileLength = file.getInt();

		file.order(ByteOrder.LITTLE_ENDIAN);
		version = file.getInt();
		checkVersion();
		shapeType = ShapeType.forID(file.getInt());

		minX = file.getDouble();
		minY = file.getDouble();
		maxX = file.getDouble();
		maxY = file.getDouble();

		// skip remaining unused bytes
		file.order(ByteOrder.BIG_ENDIAN);// well they may not be unused
		// forever...
		file.position(file.position() + 32);

	}

	public void write(WriteBufferManager shapeBuffer, ShapeType type,
			int numGeoms, int length, double minX, double minY, double maxX,
			double maxY) throws IOException {
		shapeBuffer.order(ByteOrder.BIG_ENDIAN);

		shapeBuffer.putInt(MAGIC);

		for (int i = 0; i < 5; i++) {
			shapeBuffer.putInt(0); // Skip unused part of header
		}

		shapeBuffer.putInt(length);

		shapeBuffer.order(ByteOrder.LITTLE_ENDIAN);

		shapeBuffer.putInt(VERSION);
		shapeBuffer.putInt(type.id);

		// write the bounding box
		shapeBuffer.putDouble(minX);
		shapeBuffer.putDouble(minY);
		shapeBuffer.putDouble(maxX);
		shapeBuffer.putDouble(maxY);

		// skip remaining unused bytes
		shapeBuffer.order(ByteOrder.BIG_ENDIAN);
		for (int i = 0; i < 8; i++) {
			shapeBuffer.putInt(0); // Skip unused part of header
		}
	}

	public ShapeType getShapeType() {
		return shapeType;
	}

	public int getVersion() {
		return version;
	}

	public int getFileLength() {
		return fileLength;
	}

	public double minX() {
		return minX;
	}

	public double minY() {
		return minY;
	}

	public double maxX() {
		return maxX;
	}

	public double maxY() {
		return maxY;
	}

        @Override
	public String toString() {
		StringBuilder res = new StringBuilder();
                res.append("ShapeFileHeader[ size ").append(fileLength).append(" version ");
                res.append(version).append(" shapeType ").append(shapeType);
                res.append(" bounds ").append(minX).append(",").append(minY);
                res.append(",").append(maxX).append(",").append(maxY).append(" ]");
		return res.toString();
	}
}