/** * MicroDate * Copyright 2008 by Michael Peter Christen * First released 3.7.2008 at http://yacy.net * * 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; either * version 2.1 of the License, or (at your option) any later version. * * 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. * * You should have received a copy of the GNU Lesser General Public License * along with this program in the file lgpl21.txt * If not, see <http://www.gnu.org/licenses/>. */ package net.yacy.cora.date; import java.util.Date; import net.yacy.cora.order.Base64Order; public class MicroDate { private static final long hour = 3600000L; // milliseconds of a hour private static final long day = 86400000L; // milliseconds of a day public static int microDateDays(final Date modified) { return microDateDays(modified.getTime()); } public static int microDateDays(final long modified) { // this calculates a virtual age from a given date // the purpose is to have an age in days of a given modified date // from a fixed standpoint in the past // one day has 60*60*24 seconds = 86400 seconds // we take mod 64**3 = 262144, this is the mask of the storage return (int) ((modified / day) % 262144L); } public static int microDateHoursInt(final long time) { return (int) ((time / hour) % 262144L); } public static int microDateHoursAge(final String mdhs) { return microDateHoursInt(System.currentTimeMillis()) - (int) Base64Order.enhancedCoder.decodeLong(mdhs); } public static long reverseMicroDateDays(final long microDateDays) { return Math.min(System.currentTimeMillis(), microDateDays * day); } public static void main(final String[] args) { } }