UUIDHelper.java

/**
 * Mad-Advertisement
 * Copyright (C) 2011 Thorsten Marx <thmarx@gmx.net>
 *
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * 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 General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package net.mad.ads.base.api.track.impl.local.helper;

import java.util.Date;

public class UUIDHelper {
	/**
	 * Gets a new time uuid.
	 * 
	 * @return the time uuid
	 */
	public static java.util.UUID getTimeUUID() {
		return java.util.UUID.fromString(new com.eaio.uuid.UUID().toString());
	}

	/**
	 * Returns an instance of uuid.
	 * 
	 * @param uuid
	 *            the uuid
	 * @return the java.util. uuid
	 */
	public static java.util.UUID toUUID(byte[] uuid) {
		long msb = 0;
		long lsb = 0;
		assert uuid.length == 16;
		for (int i = 0; i < 8; i++)
			msb = (msb << 8) | (uuid[i] & 0xff);
		for (int i = 8; i < 16; i++)
			lsb = (lsb << 8) | (uuid[i] & 0xff);
		long mostSigBits = msb;
		long leastSigBits = lsb;

		com.eaio.uuid.UUID u = new com.eaio.uuid.UUID(msb, lsb);
		return java.util.UUID.fromString(u.toString());
	}

	/**
	 * As byte array.
	 * 
	 * @param uuid
	 *            the uuid
	 * 
	 * @return the byte[]
	 */
	public static byte[] asByteArray(java.util.UUID uuid) {
		long msb = uuid.getMostSignificantBits();
		long lsb = uuid.getLeastSignificantBits();
		byte[] buffer = new byte[16];

		for (int i = 0; i < 8; i++) {
			buffer[i] = (byte) (msb >>> 8 * (7 - i));
		}
		for (int i = 8; i < 16; i++) {
			buffer[i] = (byte) (lsb >>> 8 * (7 - i));
		}

		return buffer;
	}

	public static java.util.UUID uuidForDate(Date d) {
		/*
		 * Magic number obtained from #cassandra's thobbs, who claims to have
		 * stolen it from a Python library.
		 */
		final long NUM_100NS_INTERVALS_SINCE_UUID_EPOCH = 0x01b21dd213814000L;

		long origTime = d.getTime();
		long time = origTime * 10000 + NUM_100NS_INTERVALS_SINCE_UUID_EPOCH;
		long timeLow = time & 0xffffffffL;
		long timeMid = time & 0xffff00000000L;
		long timeHi = time & 0xfff000000000000L;
		long upperLong = (timeLow << 32) | (timeMid >> 16) | (1 << 12)
				| (timeHi >> 48);
		return new java.util.UUID(upperLong, 0xC000000000000000L);
	}
}