    001/*
    002 *  Licensed to the Apache Software Foundation (ASF) under one or more
    003 *  contributor license agreements.  See the NOTICE file distributed with
    004 *  this work for additional information regarding copyright ownership.
    005 *  The ASF licenses this file to You under the Apache License, Version 2.0
    006 *  (the "License"); you may not use this file except in compliance with
    007 *  the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017package org.apache.commons.compress.utils;
    018
    019import java.nio.file.attribute.FileTime;
    020import java.time.Instant;
    021import java.util.Date;
    022import java.util.concurrent.TimeUnit;
    023
    024/**
    025 * Utility class for handling time-related types and conversions.
    026 * <p>
    027 * Understanding Unix vs NTFS timestamps:
    028 * </p>
    029 * <ul>
    030 * <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
    031 * Universal Time (UTC)</li>
    032 * <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
    033 * of 100-nanosecond intervals that have elapsed since 12:00 A.M. January 1, 1601 Coordinated Universal Time (UTC).</li>
    034 * </ul>
    035 *
    036 * @since 1.23
    037 */
    038public final class TimeUtils {
    039
    040    /** The amount of 100-nanosecond intervals in one millisecond. */
    041    static final long HUNDRED_NANOS_PER_MILLISECOND = TimeUnit.MILLISECONDS.toNanos(1) / 100;
    042
    043    /** The amount of 100-nanosecond intervals in one second. */
    044    static final long HUNDRED_NANOS_PER_SECOND = TimeUnit.SECONDS.toNanos(1) / 100;
    045
    046    /**
    047     * <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms724290%28v=vs.85%29.aspx">Windows File Times</a>
    048     * <p>
    049     * 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
    050     * Universal Time (UTC). This is the offset of Windows time 0 to Unix epoch in 100-nanosecond intervals.
    051     * </p>
    052     */
    053    static final long WINDOWS_EPOCH_OFFSET = -116444736000000000L;
    054
    055    /**
    056     * Tests whether a FileTime can be safely represented in the standard UNIX time.
    057     *
    058     * <p>
    059     * TODO ? If the FileTime is null, this method always returns true.
    060     * </p>
    061     *
    062     * @param time the FileTime to evaluate, can be null
    063     * @return true if the time exceeds the minimum or maximum UNIX time, false otherwise
    064     */
    065    public static boolean isUnixTime(final FileTime time) {
    066        return time == null ? true : isUnixTime(toUnixTime(time));
    067    }
    068
    069    /**
    070     * Tests whether a given number of seconds (since Epoch) can be safely represented in the standard UNIX time.
    071     *
    072     * @param seconds the number of seconds (since Epoch) to evaluate
    073     * @return true if the time can be represented in the standard UNIX time, false otherwise
    074     */
    075    public static boolean isUnixTime(final long seconds) {
    076        return Integer.MIN_VALUE <= seconds && seconds <= Integer.MAX_VALUE;
    077    }
    078
    079    /**
    080     * Converts NTFS time (100 nanosecond units since 1 January 1601) to Java time.
    081     *
    082     * @param ntfsTime the NTFS time in 100 nanosecond units
    083     * @return the Date
    084     */
    085    public static Date ntfsTimeToDate(final long ntfsTime) {
    086        final long javaHundredNanos = Math.addExact(ntfsTime, WINDOWS_EPOCH_OFFSET);
    087        final long javaMillis = Math.floorDiv(javaHundredNanos, HUNDRED_NANOS_PER_MILLISECOND);
    088        return new Date(javaMillis);
    089    }
    090
    091    /**
    092     * Converts NTFS time (100-nanosecond units since 1 January 1601) to a FileTime.
    093     *
    094     * @param ntfsTime the NTFS time in 100-nanosecond units
    095     * @return the FileTime
    096     *
    097     * @see TimeUtils#WINDOWS_EPOCH_OFFSET
    098     * @see TimeUtils#toNtfsTime(FileTime)
    099     */
    100    public static FileTime ntfsTimeToFileTime(final long ntfsTime) {
    101        final long javaHundredsNanos = Math.addExact(ntfsTime, WINDOWS_EPOCH_OFFSET);
    102        final long javaSeconds = Math.floorDiv(javaHundredsNanos, HUNDRED_NANOS_PER_SECOND);
    103        final long javaNanos = Math.floorMod(javaHundredsNanos, HUNDRED_NANOS_PER_SECOND) * 100;
    104        return FileTime.from(Instant.ofEpochSecond(javaSeconds, javaNanos));
    105    }
    106
    107    /**
    108     * Converts {@link FileTime} to a {@link Date}. If the provided FileTime is {@code null}, the returned Date is also {@code null}.
    109     *
    110     * @param fileTime the file time to be converted.
    111     * @return a {@link Date} which corresponds to the supplied time, or {@code null} if the time is {@code null}.
    112     * @see TimeUtils#toFileTime(Date)
    113     */
    114    public static Date toDate(final FileTime fileTime) {
    115        return fileTime != null ? new Date(fileTime.toMillis()) : null;
    116    }
    117
    118    /**
    119     * Converts {@link Date} to a {@link FileTime}. If the provided Date is {@code null}, the returned FileTime is also {@code null}.
    120     *
    121     * @param date the date to be converted.
    122     * @return a {@link FileTime} which corresponds to the supplied date, or {@code null} if the date is {@code null}.
    123     * @see TimeUtils#toDate(FileTime)
    124     */
    125    public static FileTime toFileTime(final Date date) {
    126        return date != null ? FileTime.fromMillis(date.getTime()) : null;
    127    }
    128
    129    /**
    130     * Converts a {@link Date} to NTFS time.
    131     *
    132     * @param date the Date
    133     * @return the NTFS time
    134     */
    135    public static long toNtfsTime(final Date date) {
    136        return toNtfsTime(date.getTime());
    137    }
    138
    139    /**
    140     * Converts a {@link FileTime} to NTFS time (100-nanosecond units since 1 January 1601).
    141     *
    142     * @param fileTime the FileTime
    143     * @return the NTFS time in 100-nanosecond units
    144     *
    145     * @see TimeUtils#WINDOWS_EPOCH_OFFSET
    146     * @see TimeUtils#ntfsTimeToFileTime(long)
    147     */
    148    public static long toNtfsTime(final FileTime fileTime) {
    149        final Instant instant = fileTime.toInstant();
    150        final long javaHundredNanos = (instant.getEpochSecond() * HUNDRED_NANOS_PER_SECOND) + (instant.getNano() / 100);
    151        return Math.subtractExact(javaHundredNanos, WINDOWS_EPOCH_OFFSET);
    152    }
    153
    154    /**
    155     * Converts Java time (milliseconds since Epoch) to NTFS time.
    156     *
    157     * @param javaTime the Java time
    158     * @return the NTFS time
    159     */
    160    public static long toNtfsTime(final long javaTime) {
    161        final long javaHundredNanos = javaTime * HUNDRED_NANOS_PER_MILLISECOND;
    162        return Math.subtractExact(javaHundredNanos, WINDOWS_EPOCH_OFFSET);
    163    }
    164
    165    /**
    166     * Converts {@link FileTime} to standard UNIX time.
    167     *
    168     * @param fileTime the original FileTime
    169     * @return the UNIX timestamp
    170     */
    171    public static long toUnixTime(final FileTime fileTime) {
    172        return fileTime.to(TimeUnit.SECONDS);
    173    }
    174
    175    /**
    176     * Truncates a FileTime to 100-nanosecond precision.
    177     *
    178     * @param fileTime the FileTime to be truncated
    179     * @return the truncated FileTime
    180     */
    181    public static FileTime truncateToHundredNanos(final FileTime fileTime) {
    182        final Instant instant = fileTime.toInstant();
    183        return FileTime.from(Instant.ofEpochSecond(instant.getEpochSecond(), (instant.getNano() / 100) * 100));
    184    }
    185
    186    /**
    187     * Converts standard UNIX time (in seconds, UTC/GMT) to {@link FileTime}.
    188     *
    189     * @param time UNIX timestamp
    190     * @return the corresponding FileTime
    191     */
    192    public static FileTime unixTimeToFileTime(final long time) {
    193        return FileTime.from(time, TimeUnit.SECONDS);
    194    }
    195
    196    /** Private constructor to prevent instantiation of this utility class. */
    197    private TimeUtils() {
    198    }
    199}