    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.commons.compress.archivers.zip;
    020
    021import java.io.Serializable;
    022import java.nio.file.attribute.FileTime;
    023import java.util.Arrays;
    024import java.util.Date;
    025import java.util.Objects;
    026import java.util.zip.ZipException;
    027
    028import org.apache.commons.io.file.attribute.FileTimes;
    029
    030/**
    031 * <p>
    032 * An extra field that stores additional file and directory timestamp data for ZIP entries. Each ZIP entry can include up to three timestamps (modify, access,
    033 * create*). The timestamps are stored as 32 bit signed integers representing seconds since Unix epoch (Jan 1st, 1970, UTC). This field improves on ZIP's
    034 * default timestamp granularity, since it allows one to store additional timestamps, and, in addition, the timestamps are stored using per-second granularity
    035 * (zip's default behavior can only store timestamps to the nearest <em>even</em> second).
    036 * </p>
    037 * <p>
    038 * Unfortunately, 32 (signed) bits can only store dates up to the year 2037, and so this extra field will eventually be obsolete. Enjoy it while it lasts!
    039 * </p>
    040 * <ul>
    041 * <li><strong>modifyTime:</strong> most recent time of file/directory modification (or file/dir creation if the entry has not been modified since it was
    042 * created).</li>
    043 * <li><strong>accessTime:</strong> most recent time file/directory was opened (for example, read from disk). Many people disable their operating systems from
    044 * updating this value using the NOATIME mount option to optimize disk behavior, and thus it's not always reliable. In those cases it's always equal to
    045 * modifyTime.</li>
    046 * <li><strong>*createTime:</strong> modern Linux file systems (for example, ext2 and newer) do not appear to store a value like this, and so it's usually
    047 * omitted altogether in the ZIP extra field. Perhaps other Unix systems track this.</li>
    048 * </ul>
    049 * <p>
    050 * We're using the field definition given in Info-Zip's source archive: zip-3.0.tar.gz/proginfo/extrafld.txt
    051 * </p>
    052 *
    053 * <pre>
    054 * Value         Size        Description
    055 * -----         ----        -----------
    056 * 0x5455        Short       tag for this extra block type ("UT")
    057 * TSize         Short       total data size for this block
    058 * Flags         Byte        info bits
    059 * (ModTime)     Long        time of last modification (UTC/GMT)
    060 * (AcTime)      Long        time of last access (UTC/GMT)
    061 * (CrTime)      Long        time of original creation (UTC/GMT)
    062 *
    063 * Central-header version:
    064 *
    065 * Value         Size        Description
    066 * -----         ----        -----------
    067 * 0x5455        Short       tag for this extra block type ("UT")
    068 * TSize         Short       total data size for this block
    069 * Flags         Byte        info bits (refers to local header!)
    070 * (ModTime)     Long        time of last modification (UTC/GMT)
    071 * </pre>
    072 *
    073 * @since 1.5
    074 */
    075public class X5455_ExtendedTimestamp implements ZipExtraField, Cloneable, Serializable {
    076    private static final long serialVersionUID = 1L;
    077    /**
    078     * The header ID for this extra field.
    079     *
    080     * @since 1.23
    081     */
    082    public static final ZipShort HEADER_ID = new ZipShort(0x5455);
    083    /**
    084     * The bit set inside the flags by when the last modification time is present in this extra field.
    085     */
    086    public static final byte MODIFY_TIME_BIT = 1;
    087    /**
    088     * The bit set inside the flags by when the lasr access time is present in this extra field.
    089     */
    090    public static final byte ACCESS_TIME_BIT = 2;
    091    /**
    092     * The bit set inside the flags by when the original creation time is present in this extra field.
    093     */
    094    public static final byte CREATE_TIME_BIT = 4;
    095
    096    /**
    097     * Utility method converts java.util.Date (milliseconds since epoch) into a ZipLong (seconds since epoch).
    098     * <p/>
    099     * Also makes sure the converted ZipLong is not too big to fit in 32 unsigned bits.
    100     *
    101     * @param d java.util.Date to convert to ZipLong
    102     * @return ZipLong
    103     */
    104    private static ZipLong dateToZipLong(final Date d) {
    105        if (d == null) {
    106            return null;
    107        }
    108        return unixTimeToZipLong(d.getTime() / 1000);
    109    }
    110
    111    /**
    112     * Utility method converts {@link FileTime} into a ZipLong (seconds since epoch).
    113     * <p/>
    114     * Also makes sure the converted ZipLong is not too big to fit in 32 unsigned bits.
    115     *
    116     * @param time {@link FileTime} to convert to ZipLong
    117     * @return ZipLong
    118     */
    119    private static ZipLong fileTimeToZipLong(final FileTime time) {
    120        return time == null ? null : unixTimeToZipLong(FileTimes.toUnixTime(time));
    121    }
    122
    123    private static FileTime unixTimeToFileTime(final ZipLong unixTime) {
    124        return unixTime != null ? FileTimes.fromUnixTime(unixTime.getIntValue()) : null;
    125    }
    126    // The 3 boolean fields (below) come from this flag's byte. The remaining 5 bits
    127    // are ignored according to the current version of the spec (December 2012).
    128
    129    private static ZipLong unixTimeToZipLong(final long unixTime) {
    130        if (!FileTimes.isUnixTime(unixTime)) {
    131            throw new IllegalArgumentException("X5455 timestamps must fit in a signed 32 bit integer: " + unixTime);
    132        }
    133        return new ZipLong(unixTime);
    134    }
    135
    136    private static Date zipLongToDate(final ZipLong unixTime) {
    137        return unixTime != null ? new Date(unixTime.getIntValue() * 1000L) : null;
    138    }
    139
    140    private byte flags;
    141    // Note: even if bit1 and bit2 are set, the Central data will still not contain
    142    // access/create fields: only local data ever holds those! This causes
    143    // some of our implementation to look a little odd, with seemingly spurious
    144    // != null and length checks.
    145    private boolean bit0_modifyTimePresent;
    146    private boolean bit1_accessTimePresent;
    147    private boolean bit2_createTimePresent;
    148    private ZipLong modifyTime;
    149    private ZipLong accessTime;
    150    private ZipLong createTime;
    151
    152    /**
    153     * Constructor for X5455_ExtendedTimestamp.
    154     */
    155    public X5455_ExtendedTimestamp() {
    156    }
    157
    158    @Override
    159    public Object clone() throws CloneNotSupportedException {
    160        return super.clone();
    161    }
    162
    163    @Override
    164    public boolean equals(final Object o) {
    165        if (o instanceof X5455_ExtendedTimestamp) {
    166            final X5455_ExtendedTimestamp xf = (X5455_ExtendedTimestamp) o;
    167            // The ZipLong==ZipLong clauses handle the cases where both are null.
    168            // and only last 3 bits of flags matter.
    169            return (flags & 0x07) == (xf.flags & 0x07) && Objects.equals(modifyTime, xf.modifyTime) && Objects.equals(accessTime, xf.accessTime)
    170                    && Objects.equals(createTime, xf.createTime);
    171        }
    172        return false;
    173    }
    174
    175    /**
    176     * Gets the access time as a {@link FileTime} of this ZIP entry, or null if no such timestamp exists in the ZIP entry. The milliseconds are always zeroed
    177     * out, since the underlying data offers only per-second precision.
    178     *
    179     * @return modify time as {@link FileTime} or null.
    180     * @since 1.23
    181     */
    182    public FileTime getAccessFileTime() {
    183        return unixTimeToFileTime(accessTime);
    184    }
    185
    186    /**
    187     * Gets the access time as a java.util.Date of this ZIP entry, or null if no such timestamp exists in the ZIP entry. The milliseconds are always zeroed out,
    188     * since the underlying data offers only per-second precision.
    189     *
    190     * @return access time as java.util.Date or null.
    191     */
    192    public Date getAccessJavaTime() {
    193        return zipLongToDate(accessTime);
    194    }
    195
    196    /**
    197     * Gets the access time (seconds since epoch) of this ZIP entry as a ZipLong object, or null if no such timestamp exists in the ZIP entry.
    198     *
    199     * @return access time (seconds since epoch) or null.
    200     */
    201    public ZipLong getAccessTime() {
    202        return accessTime;
    203    }
    204
    205    /**
    206     * Gets the actual data to put into central directory data - without Header-ID or length specifier.
    207     *
    208     * @return the central directory data
    209     */
    210    @Override
    211    public byte[] getCentralDirectoryData() {
    212        // Truncate out create & access time (last 8 bytes) from
    213        // the copy of the local data we obtained:
    214        return Arrays.copyOf(getLocalFileDataData(), getCentralDirectoryLength().getValue());
    215    }
    216
    217    /**
    218     * Gets the length of the extra field in the local file data - without Header-ID or length specifier.
    219     *
    220     * <p>
    221     * For X5455 the central length is often smaller than the local length, because central cannot contain access or create timestamps.
    222     * </p>
    223     *
    224     * @return a {@code ZipShort} for the length of the data of this extra field
    225     */
    226    @Override
    227    public ZipShort getCentralDirectoryLength() {
    228        return new ZipShort(1 + (bit0_modifyTimePresent ? 4 : 0));
    229    }
    230
    231    /**
    232     * Gets the create time as a {@link FileTime} of this ZIP entry, or null if no such timestamp exists in the ZIP entry. The milliseconds are always zeroed
    233     * out, since the underlying data offers only per-second precision.
    234     *
    235     * @return modify time as {@link FileTime} or null.
    236     * @since 1.23
    237     */
    238    public FileTime getCreateFileTime() {
    239        return unixTimeToFileTime(createTime);
    240    }
    241
    242    /**
    243     * <p>
    244     * Gets the create time as a java.util.Date of this ZIP entry, or null if no such timestamp exists in the ZIP entry. The milliseconds are always zeroed out,
    245     * since the underlying data offers only per-second precision.
    246     * </p>
    247     * <p>
    248     * Note: modern Linux file systems (for example, ext2) do not appear to store a "create time" value, and so it's usually omitted altogether in the ZIP extra
    249     * field. Perhaps other Unix systems track this.
    250     * </p>
    251     *
    252     * @return create time as java.util.Date or null.
    253     */
    254    public Date getCreateJavaTime() {
    255        return zipLongToDate(createTime);
    256    }
    257
    258    /**
    259     * <p>
    260     * Gets the create time (seconds since epoch) of this ZIP entry as a ZipLong object, or null if no such timestamp exists in the ZIP entry.
    261     * </p>
    262     * <p>
    263     * Note: modern Linux file systems (for example, ext2) do not appear to store a "create time" value, and so it's usually omitted altogether in the ZIP extra
    264     * field. Perhaps other Unix systems track this.
    265     * </p>
    266     *
    267     * @return create time (seconds since epoch) or null.
    268     */
    269    public ZipLong getCreateTime() {
    270        return createTime;
    271    }
    272
    273    /**
    274     * Gets flags byte. The flags byte tells us which of the three datestamp fields are present in the data:
    275     *
    276     * <pre>
    277     * bit0 - modify time
    278     * bit1 - access time
    279     * bit2 - create time
    280     * </pre>
    281     *
    282     * Only first 3 bits of flags are used according to the latest version of the spec (December 2012).
    283     *
    284     * @return flags byte indicating which of the three datestamp fields are present.
    285     */
    286    public byte getFlags() {
    287        return flags;
    288    }
    289
    290    /**
    291     * Gets the Header-ID.
    292     *
    293     * @return the value for the header id for this extrafield
    294     */
    295    @Override
    296    public ZipShort getHeaderId() {
    297        return HEADER_ID;
    298    }
    299
    300    /**
    301     * Gets the actual data to put into local file data - without Header-ID or length specifier.
    302     *
    303     * @return get the data
    304     */
    305    @Override
    306    public byte[] getLocalFileDataData() {
    307        final byte[] data = new byte[getLocalFileDataLength().getValue()];
    308        int pos = 0;
    309        data[pos++] = 0;
    310        if (bit0_modifyTimePresent) {
    311            data[0] |= MODIFY_TIME_BIT;
    312            System.arraycopy(modifyTime.getBytes(), 0, data, pos, 4);
    313            pos += 4;
    314        }
    315        if (bit1_accessTimePresent && accessTime != null) {
    316            data[0] |= ACCESS_TIME_BIT;
    317            System.arraycopy(accessTime.getBytes(), 0, data, pos, 4);
    318            pos += 4;
    319        }
    320        if (bit2_createTimePresent && createTime != null) {
    321            data[0] |= CREATE_TIME_BIT;
    322            System.arraycopy(createTime.getBytes(), 0, data, pos, 4);
    323            pos += 4; // NOSONAR - assignment as documentation
    324        }
    325        return data;
    326    }
    327
    328    /**
    329     * Gets the length of the extra field in the local file data - without Header-ID or length specifier.
    330     *
    331     * @return a {@code ZipShort} for the length of the data of this extra field
    332     */
    333    @Override
    334    public ZipShort getLocalFileDataLength() {
    335        return new ZipShort(1 + (bit0_modifyTimePresent ? 4 : 0) + (bit1_accessTimePresent && accessTime != null ? 4 : 0)
    336                + (bit2_createTimePresent && createTime != null ? 4 : 0));
    337    }
    338
    339    /**
    340     * Gets the modify time as a {@link FileTime} of this ZIP entry, or null if no such timestamp exists in the ZIP entry. The milliseconds are always zeroed
    341     * out, since the underlying data offers only per-second precision.
    342     *
    343     * @return modify time as {@link FileTime} or null.
    344     * @since 1.23
    345     */
    346    public FileTime getModifyFileTime() {
    347        return unixTimeToFileTime(modifyTime);
    348    }
    349
    350    /**
    351     * Gets the modify time as a java.util.Date of this ZIP entry, or null if no such timestamp exists in the ZIP entry. The milliseconds are always zeroed out,
    352     * since the underlying data offers only per-second precision.
    353     *
    354     * @return modify time as java.util.Date or null.
    355     */
    356    public Date getModifyJavaTime() {
    357        return zipLongToDate(modifyTime);
    358    }
    359
    360    /**
    361     * Gets the modify time (seconds since epoch) of this ZIP entry as a ZipLong object, or null if no such timestamp exists in the ZIP entry.
    362     *
    363     * @return modify time (seconds since epoch) or null.
    364     */
    365    public ZipLong getModifyTime() {
    366        return modifyTime;
    367    }
    368
    369    @Override
    370    public int hashCode() {
    371        int hc = -123 * (flags & 0x07); // only last 3 bits of flags matter
    372        if (modifyTime != null) {
    373            hc ^= modifyTime.hashCode();
    374        }
    375        if (accessTime != null) {
    376            // Since accessTime is often same as modifyTime,
    377            // this prevents them from XOR negating each other.
    378            hc ^= Integer.rotateLeft(accessTime.hashCode(), 11);
    379        }
    380        if (createTime != null) {
    381            hc ^= Integer.rotateLeft(createTime.hashCode(), 22);
    382        }
    383        return hc;
    384    }
    385
    386    /**
    387     * Tests whether bit0 of the flags byte is set or not, which should correspond to the presence or absence of a modify timestamp in this particular ZIP
    388     * entry.
    389     *
    390     * @return true if bit0 of the flags byte is set.
    391     */
    392    public boolean isBit0_modifyTimePresent() {
    393        return bit0_modifyTimePresent;
    394    }
    395
    396    /**
    397     * Tests whether bit1 of the flags byte is set or not, which should correspond to the presence or absence of a "last access" timestamp in this particular
    398     * ZIP entry.
    399     *
    400     * @return true if bit1 of the flags byte is set.
    401     */
    402    public boolean isBit1_accessTimePresent() {
    403        return bit1_accessTimePresent;
    404    }
    405
    406    /**
    407     * Tests whether bit2 of the flags byte is set or not, which should correspond to the presence or absence of a create timestamp in this particular ZIP
    408     * entry.
    409     *
    410     * @return true if bit2 of the flags byte is set.
    411     */
    412    public boolean isBit2_createTimePresent() {
    413        return bit2_createTimePresent;
    414    }
    415
    416    /**
    417     * Doesn't do anything special since this class always uses the same parsing logic for both central directory and local file data.
    418     */
    419    @Override
    420    public void parseFromCentralDirectoryData(final byte[] buffer, final int offset, final int length) throws ZipException {
    421        reset();
    422        parseFromLocalFileData(buffer, offset, length);
    423    }
    424
    425    /**
    426     * Populate data from this array as if it was in local file data.
    427     *
    428     * @param data   an array of bytes
    429     * @param offset the start offset
    430     * @param length the number of bytes in the array from offset
    431     * @throws java.util.zip.ZipException on error
    432     */
    433    @Override
    434    public void parseFromLocalFileData(final byte[] data, int offset, final int length) throws ZipException {
    435        reset();
    436        if (length < 1) {
    437            throw new ZipException("X5455_ExtendedTimestamp too short, only " + length + " bytes");
    438        }
    439        final int len = offset + length;
    440        setFlags(data[offset++]);
    441        if (bit0_modifyTimePresent && offset + 4 <= len) {
    442            modifyTime = new ZipLong(data, offset);
    443            offset += 4;
    444        } else {
    445            bit0_modifyTimePresent = false;
    446        }
    447        if (bit1_accessTimePresent && offset + 4 <= len) {
    448            accessTime = new ZipLong(data, offset);
    449            offset += 4;
    450        } else {
    451            bit1_accessTimePresent = false;
    452        }
    453        if (bit2_createTimePresent && offset + 4 <= len) {
    454            createTime = new ZipLong(data, offset);
    455            offset += 4; // NOSONAR - assignment as documentation
    456        } else {
    457            bit2_createTimePresent = false;
    458        }
    459    }
    460
    461    /**
    462     * Reset state back to newly constructed state. Helps us make sure parse() calls always generate clean results.
    463     */
    464    private void reset() {
    465        setFlags((byte) 0);
    466        this.modifyTime = null;
    467        this.accessTime = null;
    468        this.createTime = null;
    469    }
    470
    471    /**
    472     * <p>
    473     * Sets the acccess time as a {@link FileTime} of this ZIP entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
    474     * </p>
    475     * <p>
    476     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    477     * flags is also set.
    478     * </p>
    479     *
    480     * @param time access time as {@link FileTime}
    481     * @since 1.23
    482     */
    483    public void setAccessFileTime(final FileTime time) {
    484        setAccessTime(fileTimeToZipLong(time));
    485    }
    486
    487    /**
    488     * <p>
    489     * Sets the access time as a java.util.Date of this ZIP entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
    490     * </p>
    491     * <p>
    492     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    493     * flags is also set.
    494     * </p>
    495     *
    496     * @param d access time as java.util.Date
    497     */
    498    public void setAccessJavaTime(final Date d) {
    499        setAccessTime(dateToZipLong(d));
    500    }
    501
    502    /**
    503     * <p>
    504     * Sets the access time (seconds since epoch) of this ZIP entry using a ZipLong object
    505     * </p>
    506     * <p>
    507     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    508     * flags is also set.
    509     * </p>
    510     *
    511     * @param l ZipLong of the access time (seconds per epoch)
    512     */
    513    public void setAccessTime(final ZipLong l) {
    514        bit1_accessTimePresent = l != null;
    515        flags = (byte) (l != null ? flags | ACCESS_TIME_BIT : flags & ~ACCESS_TIME_BIT);
    516        this.accessTime = l;
    517    }
    518
    519    /**
    520     * <p>
    521     * Sets the create time as a {@link FileTime} of this ZIP entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
    522     * </p>
    523     * <p>
    524     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    525     * flags is also set.
    526     * </p>
    527     *
    528     * @param time create time as {@link FileTime}
    529     * @since 1.23
    530     */
    531    public void setCreateFileTime(final FileTime time) {
    532        setCreateTime(fileTimeToZipLong(time));
    533    }
    534
    535    /**
    536     * <p>
    537     * Sets the create time as a java.util.Date of this ZIP entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
    538     * </p>
    539     * <p>
    540     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    541     * flags is also set.
    542     * </p>
    543     *
    544     * @param d create time as java.util.Date
    545     */
    546    public void setCreateJavaTime(final Date d) {
    547        setCreateTime(dateToZipLong(d));
    548    }
    549
    550    /**
    551     * <p>
    552     * Sets the create time (seconds since epoch) of this ZIP entry using a ZipLong object
    553     * </p>
    554     * <p>
    555     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    556     * flags is also set.
    557     * </p>
    558     *
    559     * @param l ZipLong of the create time (seconds per epoch)
    560     */
    561    public void setCreateTime(final ZipLong l) {
    562        bit2_createTimePresent = l != null;
    563        flags = (byte) (l != null ? flags | CREATE_TIME_BIT : flags & ~CREATE_TIME_BIT);
    564        this.createTime = l;
    565    }
    566
    567    /**
    568     * Sets flags byte. The flags byte tells us which of the three datestamp fields are present in the data:
    569     *
    570     * <pre>
    571     * bit0 - modify time
    572     * bit1 - access time
    573     * bit2 - create time
    574     * </pre>
    575     *
    576     * Only first 3 bits of flags are used according to the latest version of the spec (December 2012).
    577     *
    578     * @param flags flags byte indicating which of the three datestamp fields are present.
    579     */
    580    public void setFlags(final byte flags) {
    581        this.flags = flags;
    582        this.bit0_modifyTimePresent = (flags & MODIFY_TIME_BIT) == MODIFY_TIME_BIT;
    583        this.bit1_accessTimePresent = (flags & ACCESS_TIME_BIT) == ACCESS_TIME_BIT;
    584        this.bit2_createTimePresent = (flags & CREATE_TIME_BIT) == CREATE_TIME_BIT;
    585    }
    586
    587    /**
    588     * <p>
    589     * Sets the modify time as a {@link FileTime} of this ZIP entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
    590     * </p>
    591     * <p>
    592     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    593     * flags is also set.
    594     * </p>
    595     *
    596     * @param time modify time as {@link FileTime}
    597     * @since 1.23
    598     */
    599    public void setModifyFileTime(final FileTime time) {
    600        setModifyTime(fileTimeToZipLong(time));
    601    }
    602
    603    /**
    604     * <p>
    605     * Sets the modify time as a java.util.Date of this ZIP entry. Supplied value is truncated to per-second precision (milliseconds zeroed-out).
    606     * </p>
    607     * <p>
    608     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    609     * flags is also set.
    610     * </p>
    611     *
    612     * @param d modify time as java.util.Date
    613     */
    614    public void setModifyJavaTime(final Date d) {
    615        setModifyTime(dateToZipLong(d));
    616    }
    617
    618    /**
    619     * <p>
    620     * Sets the modify time (seconds since epoch) of this ZIP entry using a ZipLong object.
    621     * </p>
    622     * <p>
    623     * Note: the setters for flags and timestamps are decoupled. Even if the timestamp is not-null, it will only be written out if the corresponding bit in the
    624     * flags is also set.
    625     * </p>
    626     *
    627     * @param l ZipLong of the modify time (seconds per epoch)
    628     */
    629    public void setModifyTime(final ZipLong l) {
    630        bit0_modifyTimePresent = l != null;
    631        flags = (byte) (l != null ? flags | MODIFY_TIME_BIT : flags & ~MODIFY_TIME_BIT);
    632        this.modifyTime = l;
    633    }
    634
    635    /**
    636     * Returns a String representation of this class useful for debugging purposes.
    637     *
    638     * @return A String representation of this class useful for debugging purposes.
    639     */
    640    @Override
    641    public String toString() {
    642        final StringBuilder buf = new StringBuilder();
    643        buf.append("0x5455 Zip Extra Field: Flags=");
    644        buf.append(Integer.toBinaryString(ZipUtil.unsignedIntToSignedByte(flags))).append(" ");
    645        if (bit0_modifyTimePresent && modifyTime != null) {
    646            final Date m = getModifyJavaTime();
    647            buf.append(" Modify:[").append(m).append("] ");
    648        }
    649        if (bit1_accessTimePresent && accessTime != null) {
    650            final Date a = getAccessJavaTime();
    651            buf.append(" Access:[").append(a).append("] ");
    652        }
    653        if (bit2_createTimePresent && createTime != null) {
    654            final Date c = getCreateJavaTime();
    655            buf.append(" Create:[").append(c).append("] ");
    656        }
    657        return buf.toString();
    658    }
    659}