package com.sun.jna.examples.win32;
import java.util.Date;
/**
*
* Parts of this class Copyright 2002-2004 Apache Software Foundation.
* @author Rainer Klute (klute@rainer-klute.de) for the Apache Software Foundation (org.apache.poi.hpsf)
*/
public final class Utils {
/**
* <p>The difference between the Windows epoch (1601-01-01
* 00:00:00) and the Unix epoch (1970-01-01 00:00:00) in
* milliseconds: 11644473600000L. (Use your favorite spreadsheet
* program to verify the correctness of this value. By the way,
* did you notice that you can tell from the epochs which
* operating system is the modern one? :-))</p>
*/
private static final long EPOCH_DIFF = 11644473600000L;
/**
* <p>Converts a Windows FILETIME into a {@link Date}. The Windows
* FILETIME structure holds a date and time associated with a
* file. The structure identifies a 64-bit integer specifying the
* number of 100-nanosecond intervals which have passed since
* January 1, 1601. This 64-bit value is split into the two double
* words stored in the structure.</p>
*
* @param high The higher double word of the FILETIME structure.
* @param low The lower double word of the FILETIME structure.
* @return The Windows FILETIME as a {@link Date}.
*/
public static Date filetimeToDate(final int high, final int low) {
final long filetime = (long) high << 32 | low & 0xffffffffL;
final long ms_since_16010101 = filetime / (1000 * 10);
final long ms_since_19700101 = ms_since_16010101 - EPOCH_DIFF;
return new Date(ms_since_19700101);
}
/**
* <p>Converts a {@link Date} into a filetime.</p>
*
* @param date The date to be converted
* @return The filetime
*
* @see #filetimeToDate
*/
public static long dateToFileTime(final Date date) {
final long ms_since_19700101 = date.getTime();
final long ms_since_16010101 = ms_since_19700101 + EPOCH_DIFF;
return ms_since_16010101 * 1000 * 10;
}
private Utils() {
}
}