    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 *
    017 */
    018package org.apache.commons.compress.archivers.zip;
    019
    020import java.io.IOException;
    021import java.math.BigInteger;
    022import java.time.Instant;
    023import java.time.LocalDateTime;
    024import java.time.ZoneId;
    025import java.util.Arrays;
    026import java.util.Calendar;
    027import java.util.Date;
    028import java.util.zip.CRC32;
    029import java.util.zip.ZipEntry;
    030
    031/**
    032 * Utility class for handling DOS and Java time conversions.
    033 * @Immutable
    034 */
    035public abstract class ZipUtil {
    036
    037    /**
    038     * DOS time constant for representing timestamps before 1980.
    039     * Smallest date/time ZIP can handle.
    040     * <p>
    041     * MS-DOS records file dates and times as packed 16-bit values. An MS-DOS date has the following format.
    042     * </p>
    043     * <p>
    044     * Bits     Contents
    045     * </p>
    046     * <ul>
    047     *   <li>0-4: Day of the month (1-31).</li>
    048     *   <li>5-8: Month (1 = January, 2 = February, and so on).</li>
    049     *   <li>9-15: Year offset from 1980 (add 1980 to get the actual year).</li>
    050     * </ul>
    051     *
    052     * An MS-DOS time has the following format.
    053     * <p>
    054     * Bits     Contents
    055     * </p>
    056     * <ul>
    057     *   <li>0-4: Second divided by 2.</li>
    058     *   <li>5-10: Minute (0-59).</li>
    059     *   <li>11-15: Hour (0-23 on a 24-hour clock).</li>
    060     * </ul>
    061     *
    062     * This constant expresses the minimum DOS date of January 1st 1980 at 00:00:00 or, bit-by-bit:
    063     * <ul>
    064     * <li>Year: 0000000</li>
    065     * <li>Month: 0001</li>
    066     * <li>Day: 00001</li>
    067     * <li>Hour: 00000</li>
    068     * <li>Minute: 000000</li>
    069     * <li>Seconds: 00000</li>
    070     * </ul>
    071     *
    072     * <p>
    073     * This was copied from {@link ZipEntry}.
    074     * </p>
    075     *
    076     * @since 1.23
    077     */
    078    private static final long DOSTIME_BEFORE_1980 = (1 << 21) | (1 << 16); // 0x210000
    079
    080    /**
    081     * Approximately 128 years, in milliseconds (ignoring leap years, etc.).
    082     *
    083     * <p>
    084     * This establish an approximate high-bound value for DOS times in
    085     * milliseconds since epoch, used to enable an efficient but
    086     * sufficient bounds check to avoid generating extended last modified
    087     * time entries.
    088     * </p>
    089     * <p>
    090     * Calculating the exact number is locale dependent, would require loading
    091     * TimeZone data eagerly, and would make little practical sense. Since DOS
    092     * times theoretically go to 2107 - with compatibility not guaranteed
    093     * after 2099 - setting this to a time that is before but near 2099
    094     * should be sufficient.
    095     * </p>
    096     *
    097     * <p>
    098     * This was copied from {@link ZipEntry}.
    099     * </p>
    100     *
    101     * @since 1.23
    102     */
    103    private static final long UPPER_DOSTIME_BOUND = 128L * 365 * 24 * 60 * 60 * 1000;
    104
    105    /**
    106     * Assumes a negative integer really is a positive integer that
    107     * has wrapped around and re-creates the original value.
    108     *
    109     * @param i the value to treat as unsigned int.
    110     * @return the unsigned int as a long.
    111     */
    112    public static long adjustToLong(final int i) {
    113        if (i < 0) {
    114            return 2 * ((long) Integer.MAX_VALUE) + 2 + i;
    115        }
    116        return i;
    117    }
    118
    119    /**
    120     * Converts a BigInteger into a long, and blows up
    121     * (NumberFormatException) if the BigInteger is too big.
    122     *
    123     * @param big BigInteger to convert.
    124     * @return long representation of the BigInteger.
    125     */
    126    static long bigToLong(final BigInteger big) {
    127        if (big.bitLength() <= 63) { // bitLength() doesn't count the sign bit.
    128            return big.longValue();
    129        }
    130        throw new NumberFormatException("The BigInteger cannot fit inside a 64 bit java long: [" + big + "]");
    131    }
    132
    133    /**
    134     * Tests if this library is able to read or write the given entry.
    135     */
    136    static boolean canHandleEntryData(final ZipArchiveEntry entry) {
    137        return supportsEncryptionOf(entry) && supportsMethodOf(entry);
    138    }
    139
    140    /**
    141     * Checks whether the entry requires features not (yet) supported
    142     * by the library and throws an exception if it does.
    143     */
    144    static void checkRequestedFeatures(final ZipArchiveEntry ze)
    145        throws UnsupportedZipFeatureException {
    146        if (!supportsEncryptionOf(ze)) {
    147            throw
    148                new UnsupportedZipFeatureException(UnsupportedZipFeatureException
    149                                                   .Feature.ENCRYPTION, ze);
    150        }
    151        if (!supportsMethodOf(ze)) {
    152            final ZipMethod m = ZipMethod.getMethodByCode(ze.getMethod());
    153            if (m == null) {
    154                throw
    155                    new UnsupportedZipFeatureException(UnsupportedZipFeatureException
    156                                                       .Feature.METHOD, ze);
    157            }
    158            throw new UnsupportedZipFeatureException(m, ze);
    159        }
    160    }
    161
    162    /**
    163     * Creates a copy of the given array - or return null if the
    164     * argument is null.
    165     */
    166    static byte[] copy(final byte[] from) {
    167        if (from != null) {
    168            return Arrays.copyOf(from, from.length);
    169        }
    170        return null;
    171    }
    172
    173
    174    static void copy(final byte[] from, final byte[] to, final int offset) {
    175        if (from != null) {
    176            System.arraycopy(from, 0, to, offset, from.length);
    177        }
    178    }
    179
    180    private static Date dosToJavaDate(final long dosTime) {
    181        final Calendar cal = Calendar.getInstance();
    182        // CheckStyle:MagicNumberCheck OFF - no point
    183        cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980);
    184        cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1);
    185        cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f);
    186        cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f);
    187        cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f);
    188        cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e);
    189        cal.set(Calendar.MILLISECOND, 0);
    190        // CheckStyle:MagicNumberCheck ON
    191        return cal.getTime();
    192    }
    193
    194    /**
    195     * Converts DOS time to Java time (number of milliseconds since
    196     * epoch).
    197     * @param dosTime time to convert
    198     * @return converted time
    199     */
    200    public static long dosToJavaTime(final long dosTime) {
    201        return dosToJavaDate(dosTime).getTime();
    202    }
    203
    204    /**
    205     * Converts a DOS date/time field to a Date object.
    206     *
    207     * @param zipDosTime contains the stored DOS time.
    208     * @return a Date instance corresponding to the given time.
    209     */
    210    public static Date fromDosTime(final ZipLong zipDosTime) {
    211        final long dosTime = zipDosTime.getValue();
    212        return dosToJavaDate(dosTime);
    213    }
    214
    215    /**
    216     * If the stored CRC matches the one of the given name, return the
    217     * Unicode name of the given field.
    218     *
    219     * <p>If the field is null or the CRCs don't match, return null
    220     * instead.</p>
    221     */
    222    private static
    223        String getUnicodeStringIfOriginalMatches(final AbstractUnicodeExtraField f,
    224                                                 final byte[] orig) {
    225        if (f != null) {
    226            final CRC32 crc32 = new CRC32();
    227            crc32.update(orig);
    228            final long origCRC32 = crc32.getValue();
    229
    230            if (origCRC32 == f.getNameCRC32()) {
    231                try {
    232                    return ZipEncodingHelper
    233                        .UTF8_ZIP_ENCODING.decode(f.getUnicodeName());
    234                } catch (final IOException ex) {
    235                    // UTF-8 unsupported?  should be impossible the
    236                    // Unicode*ExtraField must contain some bad bytes
    237                }
    238            }
    239        }
    240        // TODO log this anywhere?
    241        return null;
    242    }
    243
    244    /**
    245     * Tests whether a given time (in milliseconds since Epoch) can be safely represented as DOS time
    246     *
    247     * @param time time in milliseconds since epoch
    248     * @return true if the time can be safely represented as DOS time, false otherwise
    249     * @since 1.23
    250     */
    251    public static boolean isDosTime(final long time) {
    252        return time <= UPPER_DOSTIME_BOUND && javaToDosTime(time) != DOSTIME_BEFORE_1980;
    253    }
    254
    255    private static LocalDateTime javaEpochToLocalDateTime(final long time) {
    256        final Instant instant = Instant.ofEpochMilli(time);
    257        return LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
    258    }
    259
    260    // version with integer overflow fixed - see https://bugs.openjdk.org/browse/JDK-8130914
    261    private static long javaToDosTime(final long t) {
    262        final LocalDateTime ldt = javaEpochToLocalDateTime(t);
    263        if (ldt.getYear() < 1980) {
    264            return DOSTIME_BEFORE_1980;
    265        }
    266        return ((ldt.getYear() - 1980) << 25
    267                | ldt.getMonthValue() << 21
    268                | ldt.getDayOfMonth() << 16
    269                | ldt.getHour() << 11
    270                | ldt.getMinute() << 5
    271                | ldt.getSecond() >> 1) & 0xffffffffL;
    272    }
    273
    274    /**
    275     * <p>
    276     * Converts a long into a BigInteger.  Negative numbers between -1 and
    277     * -2^31 are treated as unsigned 32 bit (e.g., positive) integers.
    278     * Negative numbers below -2^31 cause an IllegalArgumentException
    279     * to be thrown.
    280     * </p>
    281     *
    282     * @param l long to convert to BigInteger.
    283     * @return BigInteger representation of the provided long.
    284     */
    285    static BigInteger longToBig(long l) {
    286        if (l < Integer.MIN_VALUE) {
    287            throw new IllegalArgumentException("Negative longs < -2^31 not permitted: [" + l + "]");
    288        }
    289        if (l < 0 && l >= Integer.MIN_VALUE) {
    290            // If someone passes in a -2, they probably mean 4294967294
    291            // (For example, Unix UID/GID's are 32 bit unsigned.)
    292            l = ZipUtil.adjustToLong((int) l);
    293        }
    294        return BigInteger.valueOf(l);
    295    }
    296
    297    /**
    298     * Reverses a byte[] array.  Reverses in-place (thus provided array is
    299     * mutated), but also returns same for convenience.
    300     *
    301     * @param array to reverse (mutated in-place, but also returned for
    302     *        convenience).
    303     *
    304     * @return the reversed array (mutated in-place, but also returned for
    305     *        convenience).
    306     * @since 1.5
    307     */
    308    public static byte[] reverse(final byte[] array) {
    309        final int z = array.length - 1; // position of last element
    310        for (int i = 0; i < array.length / 2; i++) {
    311            final byte x = array[i];
    312            array[i] = array[z - i];
    313            array[z - i] = x;
    314        }
    315        return array;
    316    }
    317
    318    /**
    319     * If the entry has Unicode*ExtraFields and the CRCs of the
    320     * names/comments match those of the extra fields, transfer the
    321     * known Unicode values from the extra field.
    322     */
    323    static void setNameAndCommentFromExtraFields(final ZipArchiveEntry ze,
    324                                                 final byte[] originalNameBytes,
    325                                                 final byte[] commentBytes) {
    326        final ZipExtraField nameCandidate = ze.getExtraField(UnicodePathExtraField.UPATH_ID);
    327        final UnicodePathExtraField name = nameCandidate instanceof UnicodePathExtraField
    328            ? (UnicodePathExtraField) nameCandidate : null;
    329        final String newName = getUnicodeStringIfOriginalMatches(name,
    330                                                           originalNameBytes);
    331        if (newName != null) {
    332            ze.setName(newName);
    333            ze.setNameSource(ZipArchiveEntry.NameSource.UNICODE_EXTRA_FIELD);
    334        }
    335
    336        if (commentBytes != null && commentBytes.length > 0) {
    337            final ZipExtraField cmtCandidate = ze.getExtraField(UnicodeCommentExtraField.UCOM_ID);
    338            final UnicodeCommentExtraField cmt = cmtCandidate instanceof UnicodeCommentExtraField
    339                ? (UnicodeCommentExtraField) cmtCandidate : null;
    340            final String newComment =
    341                getUnicodeStringIfOriginalMatches(cmt, commentBytes);
    342            if (newComment != null) {
    343                ze.setComment(newComment);
    344                ze.setCommentSource(ZipArchiveEntry.CommentSource.UNICODE_EXTRA_FIELD);
    345            }
    346        }
    347    }
    348
    349    /**
    350     * Converts a signed byte into an unsigned integer representation
    351     * (e.g., -1 becomes 255).
    352     *
    353     * @param b byte to convert to int
    354     * @return int representation of the provided byte
    355     * @since 1.5
    356     */
    357    public static int signedByteToUnsignedInt(final byte b) {
    358        if (b >= 0) {
    359            return b;
    360        }
    361        return 256 + b;
    362    }
    363
    364    /**
    365     * Tests if this library supports the encryption used by the given
    366     * entry.
    367     *
    368     * @return true if the entry isn't encrypted at all
    369     */
    370    private static boolean supportsEncryptionOf(final ZipArchiveEntry entry) {
    371        return !entry.getGeneralPurposeBit().usesEncryption();
    372    }
    373
    374    /**
    375     * Tests if this library supports the compression method used by
    376     * the given entry.
    377     *
    378     * @return true if the compression method is supported
    379     */
    380    private static boolean supportsMethodOf(final ZipArchiveEntry entry) {
    381        return entry.getMethod() == ZipEntry.STORED
    382            || entry.getMethod() == ZipMethod.UNSHRINKING.getCode()
    383            || entry.getMethod() == ZipMethod.IMPLODING.getCode()
    384            || entry.getMethod() == ZipEntry.DEFLATED
    385            || entry.getMethod() == ZipMethod.ENHANCED_DEFLATED.getCode()
    386            || entry.getMethod() == ZipMethod.BZIP2.getCode();
    387    }
    388
    389
    390    /**
    391     * Converts a Date object to a DOS date/time field.
    392     *
    393     * @param time the {@code Date} to convert
    394     * @return the date as a {@code ZipLong}
    395     */
    396    public static ZipLong toDosTime(final Date time) {
    397        return new ZipLong(toDosTime(time.getTime()));
    398    }
    399
    400    /**
    401     * Converts a Date object to a DOS date/time field.
    402     *
    403     * <p>Stolen from InfoZip's {@code fileio.c}</p>
    404     * @param t number of milliseconds since the epoch
    405     * @return the date as a byte array
    406     */
    407    public static byte[] toDosTime(final long t) {
    408        final byte[] result = new byte[4];
    409        toDosTime(t, result, 0);
    410        return result;
    411    }
    412
    413    /**
    414     * Converts a Date object to a DOS date/time field.
    415     *
    416     * <p>Stolen from InfoZip's {@code fileio.c}</p>
    417     * @param t number of milliseconds since the epoch
    418     * @param buf the output buffer
    419     * @param offset
    420     *         The offset within the output buffer of the first byte to be written.
    421     *         must be non-negative and no larger than {@code buf.length-4}
    422     */
    423    public static void toDosTime(final long t, final byte[] buf, final int offset) {
    424        ZipLong.putLong(javaToDosTime(t), buf, offset);
    425    }
    426
    427    /**
    428     * Converts an unsigned integer to a signed byte (e.g., 255 becomes -1).
    429     *
    430     * @param i integer to convert to byte
    431     * @return byte representation of the provided int
    432     * @throws IllegalArgumentException if the provided integer is not inside the range [0,255].
    433     * @since 1.5
    434     */
    435    public static byte unsignedIntToSignedByte(final int i) {
    436        if (i > 255 || i < 0) {
    437            throw new IllegalArgumentException("Can only convert non-negative integers between [0,255] to byte: [" + i + "]");
    438        }
    439        if (i < 128) {
    440            return (byte) i;
    441        }
    442        return (byte) (i - 256);
    443    }
    444}