org.mobicents.media.server.NtpTimeStampUtil Maven / Gradle / Ivy
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* Copyright 2011, Red Hat, Inc. and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This 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 software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.mobicents.media.server;
/**
*
* @author amit bhayani
*
*/
public class NtpTimeStampUtil {
/**
* baseline NTP time if bit-0=0 -> 7-Feb-2036 @ 06:28:16 UTC
*/
private static final long msb0baseTime = 2085978496000L;
/**
* baseline NTP time if bit-0=1 -> 1-Jan-1900 @ 01:00:00 UTC
*/
private static final long msb1baseTime = -2208988800000L;
private static long[] time = new long[2];
public static long getTime(long seconds, long fraction) {
// Use round-off on fractional part to preserve going to lower precision
fraction = Math.round(1000D * fraction / 0x100000000L);
long msb = seconds & 0x80000000L;
if (msb == 0) {
// use base: 7-Feb-2036 @ 06:28:16 UTC
return msb0baseTime + (seconds * 1000) + fraction;
} else {
// use base: 1-Jan-1900 @ 01:00:00 UTC
return msb1baseTime + (seconds * 1000) + fraction;
}
}
public static long[] toNtpTime(long t) {
boolean useBase1 = t < msb0baseTime; // time < Feb-2036
long baseTime;
if (useBase1) {
baseTime = t - msb1baseTime; // dates <= Feb-2036
} else {
// if base0 needed for dates >= Feb-2036
baseTime = t - msb0baseTime;
}
long seconds = baseTime / 1000;
long fraction = ((baseTime % 1000) * 0x100000000L) / 1000;
if (useBase1) {
seconds |= 0x80000000L; // set high-order bit if msb1baseTime 1900 used
}
time[0] = seconds;
time[1] = fraction;
return time;
}
}