TimeUtils.java
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.compress.utils;
import java.nio.file.attribute.FileTime;
import java.time.Instant;
import java.util.Date;
import java.util.concurrent.TimeUnit;
/**
* Utility class for handling time-related types and conversions.
* <p>
* Understanding Unix vs NTFS timestamps:
* </p>
* <ul>
* <li>A <a href="https://en.wikipedia.org/wiki/Unix_time">Unix timestamp</a> is a primitive long starting at the Unix Epoch on January 1st, 1970 at Coordinated
* Universal Time (UTC)</li>
* <li>An <a href="https://learn.microsoft.com/en-us/windows/win32/sysinfo/file-times">NTFS timestamp</a> is a file time is a 64-bit value that represents the
* number of 100-nanosecond intervals that have elapsed since 12:00 A.M. January 1, 1601 Coordinated Universal Time (UTC).</li>
* </ul>
*
* @since 1.23
*/
public final class TimeUtils {
/** The amount of 100-nanosecond intervals in one millisecond. */
static final long HUNDRED_NANOS_PER_MILLISECOND = TimeUnit.MILLISECONDS.toNanos(1) / 100;
/** The amount of 100-nanosecond intervals in one second. */
static final long HUNDRED_NANOS_PER_SECOND = TimeUnit.SECONDS.toNanos(1) / 100;
/**
* <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms724290%28v=vs.85%29.aspx">Windows File Times</a>
* <p>
* A file time is a 64-bit value that represents the number of 100-nanosecond intervals that have elapsed since 12:00 A.M. January 1, 1601 Coordinated
* Universal Time (UTC). This is the offset of Windows time 0 to Unix epoch in 100-nanosecond intervals.
* </p>
*/
static final long WINDOWS_EPOCH_OFFSET = -116444736000000000L;
/**
* Tests whether a FileTime can be safely represented in the standard UNIX time.
*
* <p>
* TODO ? If the FileTime is null, this method always returns true.
* </p>
*
* @param time the FileTime to evaluate, can be null
* @return true if the time exceeds the minimum or maximum UNIX time, false otherwise
*/
public static boolean isUnixTime(final FileTime time) {
return time == null ? true : isUnixTime(toUnixTime(time));
}
/**
* Tests whether a given number of seconds (since Epoch) can be safely represented in the standard UNIX time.
*
* @param seconds the number of seconds (since Epoch) to evaluate
* @return true if the time can be represented in the standard UNIX time, false otherwise
*/
public static boolean isUnixTime(final long seconds) {
return Integer.MIN_VALUE <= seconds && seconds <= Integer.MAX_VALUE;
}
/**
* Converts NTFS time (100 nanosecond units since 1 January 1601) to Java time.
*
* @param ntfsTime the NTFS time in 100 nanosecond units
* @return the Date
*/
public static Date ntfsTimeToDate(final long ntfsTime) {
final long javaHundredNanos = Math.addExact(ntfsTime, WINDOWS_EPOCH_OFFSET);
final long javaMillis = Math.floorDiv(javaHundredNanos, HUNDRED_NANOS_PER_MILLISECOND);
return new Date(javaMillis);
}
/**
* Converts NTFS time (100-nanosecond units since 1 January 1601) to a FileTime.
*
* @param ntfsTime the NTFS time in 100-nanosecond units
* @return the FileTime
*
* @see TimeUtils#WINDOWS_EPOCH_OFFSET
* @see TimeUtils#toNtfsTime(FileTime)
*/
public static FileTime ntfsTimeToFileTime(final long ntfsTime) {
final long javaHundredsNanos = Math.addExact(ntfsTime, WINDOWS_EPOCH_OFFSET);
final long javaSeconds = Math.floorDiv(javaHundredsNanos, HUNDRED_NANOS_PER_SECOND);
final long javaNanos = Math.floorMod(javaHundredsNanos, HUNDRED_NANOS_PER_SECOND) * 100;
return FileTime.from(Instant.ofEpochSecond(javaSeconds, javaNanos));
}
/**
* Converts {@link FileTime} to a {@link Date}. If the provided FileTime is {@code null}, the returned Date is also {@code null}.
*
* @param fileTime the file time to be converted.
* @return a {@link Date} which corresponds to the supplied time, or {@code null} if the time is {@code null}.
* @see TimeUtils#toFileTime(Date)
*/
public static Date toDate(final FileTime fileTime) {
return fileTime != null ? new Date(fileTime.toMillis()) : null;
}
/**
* Converts {@link Date} to a {@link FileTime}. If the provided Date is {@code null}, the returned FileTime is also {@code null}.
*
* @param date the date to be converted.
* @return a {@link FileTime} which corresponds to the supplied date, or {@code null} if the date is {@code null}.
* @see TimeUtils#toDate(FileTime)
*/
public static FileTime toFileTime(final Date date) {
return date != null ? FileTime.fromMillis(date.getTime()) : null;
}
/**
* Converts a {@link Date} to NTFS time.
*
* @param date the Date
* @return the NTFS time
*/
public static long toNtfsTime(final Date date) {
return toNtfsTime(date.getTime());
}
/**
* Converts a {@link FileTime} to NTFS time (100-nanosecond units since 1 January 1601).
*
* @param fileTime the FileTime
* @return the NTFS time in 100-nanosecond units
*
* @see TimeUtils#WINDOWS_EPOCH_OFFSET
* @see TimeUtils#ntfsTimeToFileTime(long)
*/
public static long toNtfsTime(final FileTime fileTime) {
final Instant instant = fileTime.toInstant();
final long javaHundredNanos = instant.getEpochSecond() * HUNDRED_NANOS_PER_SECOND + instant.getNano() / 100;
return Math.subtractExact(javaHundredNanos, WINDOWS_EPOCH_OFFSET);
}
/**
* Converts Java time (milliseconds since Epoch) to NTFS time.
*
* @param javaTime the Java time
* @return the NTFS time
*/
public static long toNtfsTime(final long javaTime) {
final long javaHundredNanos = javaTime * HUNDRED_NANOS_PER_MILLISECOND;
return Math.subtractExact(javaHundredNanos, WINDOWS_EPOCH_OFFSET);
}
/**
* Converts {@link FileTime} to standard UNIX time.
*
* @param fileTime the original FileTime
* @return the UNIX timestamp
*/
public static long toUnixTime(final FileTime fileTime) {
return fileTime.to(TimeUnit.SECONDS);
}
/**
* Truncates a FileTime to 100-nanosecond precision.
*
* @param fileTime the FileTime to be truncated
* @return the truncated FileTime
*/
public static FileTime truncateToHundredNanos(final FileTime fileTime) {
final Instant instant = fileTime.toInstant();
return FileTime.from(Instant.ofEpochSecond(instant.getEpochSecond(), instant.getNano() / 100 * 100));
}
/**
* Converts standard UNIX time (in seconds, UTC/GMT) to {@link FileTime}.
*
* @param time UNIX timestamp
* @return the corresponding FileTime
*/
public static FileTime unixTimeToFileTime(final long time) {
return FileTime.from(time, TimeUnit.SECONDS);
}
/** Private constructor to prevent instantiation of this utility class. */
private TimeUtils() {
}
}