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}