ValueGetter.java

/*
 * ValueGetter.java
 *
 * PostGIS extension for PostgreSQL JDBC driver - Binary Parser
 *
 * (C) 2005 Markus Schaber, markus.schaber@logix-tt.com
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General License as published by the Free
 * Software Foundation, either 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 License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA or visit the web at
 * http://www.gnu.org.
 *
 * $Id: ValueGetter.java 9324 2012-02-27 22:08:12Z pramsey $
 */

package org.oscim.utils.wkb;

abstract class ValueGetter {
	byte[] data;
	int position;
	final byte endian;

	ValueGetter(byte[] data, byte endian) {
		this.data = data;

		this.endian = endian;
	}

	/**
	 * Get a byte, should be equal for all endians
	 * 
	 * @return ...
	 */
	byte getByte() {
		return data[position++];
	}

	int getInt() {
		int res = getInt(position);
		position += 4;
		return res;
	}

	long getLong() {
		long res = getLong(position);
		position += 8;
		return res;
	}

	/**
	 * Get a 32-Bit integer
	 * 
	 * @param index
	 *            ...
	 * @return ...
	 */
	protected abstract int getInt(int index);

	/**
	 * Get a long value. This is not needed directly, but as a nice side-effect
	 * from GetDouble.
	 * 
	 * @param index
	 *            ...
	 * @return ...
	 */
	protected abstract long getLong(int index);

	/**
	 * Get a double.
	 * 
	 * @return ...
	 */
	double getDouble() {
		long bitrep = getLong();
		return Double.longBitsToDouble(bitrep);
	}

	static class XDR extends ValueGetter {
		static final byte NUMBER = 0;

		XDR(byte[] data) {
			super(data, NUMBER);
		}

		@Override
		protected int getInt(int index) {
			return ((data[index] & 0xFF) << 24) + ((data[index + 1] & 0xFF) << 16)
			        + ((data[index + 2] & 0xFF) << 8) + (data[index + 3] & 0xFF);
		}

		@Override
		protected long getLong(int index) {

			return ((long) (data[index] & 0xFF) << 56) | ((long) (data[index + 1] & 0xFF) << 48)
			        | ((long) (data[index + 2] & 0xFF) << 40)
			        | ((long) (data[index + 3] & 0xFF) << 32)
			        | ((long) (data[index + 4] & 0xFF) << 24)
			        | ((long) (data[index + 5] & 0xFF) << 16)
			        | ((long) (data[index + 6] & 0xFF) << 8)
			        | ((long) (data[index + 7] & 0xFF) << 0);
		}
	}

	static class NDR extends ValueGetter {
		static final byte NUMBER = 1;

		NDR(byte[] data) {
			super(data, NUMBER);
		}

		@Override
		protected int getInt(int index) {
			return ((data[index + 3] & 0xFF) << 24) + ((data[index + 2] & 0xFF) << 16)
			        + ((data[index + 1] & 0xFF) << 8) + (data[index] & 0xFF);
		}

		@Override
		protected long getLong(int index) {
			return ((long) (data[index + 7] & 0xFF) << 56)
			        | ((long) (data[index + 6] & 0xFF) << 48)
			        | ((long) (data[index + 5] & 0xFF) << 40)
			        | ((long) (data[index + 4] & 0xFF) << 32)
			        | ((long) (data[index + 3] & 0xFF) << 24)
			        | ((long) (data[index + 2] & 0xFF) << 16)
			        | ((long) (data[index + 1] & 0xFF) << 8) | ((long) (data[index] & 0xFF) << 0);

		}
	}
}