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.util.Arrays;
023import java.util.Calendar;
024import java.util.Date;
025import java.util.zip.CRC32;
026import java.util.zip.ZipEntry;
027
028/**
029 * Utility class for handling DOS and Java time conversions.
030 * @Immutable
031 */
032public abstract class ZipUtil {
033    /**
034     * Smallest date/time ZIP can handle.
035     */
036    private static final byte[] DOS_TIME_MIN = ZipLong.getBytes(0x00002100L);
037
038    /**
039     * Convert a Date object to a DOS date/time field.
040     * @param time the <code>Date</code> to convert
041     * @return the date as a <code>ZipLong</code>
042     */
043    public static ZipLong toDosTime(final Date time) {
044        return new ZipLong(toDosTime(time.getTime()));
045    }
046
047    /**
048     * Convert a Date object to a DOS date/time field.
049     *
050     * <p>Stolen from InfoZip's <code>fileio.c</code></p>
051     * @param t number of milliseconds since the epoch
052     * @return the date as a byte array
053     */
054    public static byte[] toDosTime(final long t) {
055        final byte[] result = new byte[4];
056        toDosTime(t, result, 0);
057        return result;
058    }
059
060    /**
061     * Convert a Date object to a DOS date/time field.
062     *
063     * <p>Stolen from InfoZip's <code>fileio.c</code></p>
064     * @param t number of milliseconds since the epoch
065     * @param buf the output buffer
066     * @param offset
067     *         The offset within the output buffer of the first byte to be written.
068     *         must be non-negative and no larger than {@code buf.length-4}
069     */
070    public static void toDosTime(final long t, final byte[] buf, final int offset) {
071        toDosTime(Calendar.getInstance(), t, buf, offset);
072    }
073
074    static void toDosTime(final Calendar c, final long t, final byte[] buf, final int offset) {
075        c.setTimeInMillis(t);
076
077        final int year = c.get(Calendar.YEAR);
078        if (year < 1980) {
079            copy(DOS_TIME_MIN, buf, offset); // stop callers from changing the array
080            return;
081        }
082        final int month = c.get(Calendar.MONTH) + 1;
083        final long value =  ((year - 1980) << 25)
084                |         (month << 21)
085                |         (c.get(Calendar.DAY_OF_MONTH) << 16)
086                |         (c.get(Calendar.HOUR_OF_DAY) << 11)
087                |         (c.get(Calendar.MINUTE) << 5)
088                |         (c.get(Calendar.SECOND) >> 1);
089        ZipLong.putLong(value, buf, offset);
090    }
091
092
093    /**
094     * Assumes a negative integer really is a positive integer that
095     * has wrapped around and re-creates the original value.
096     *
097     * @param i the value to treat as unsigned int.
098     * @return the unsigned int as a long.
099     */
100    public static long adjustToLong(final int i) {
101        if (i < 0) {
102            return 2 * ((long) Integer.MAX_VALUE) + 2 + i;
103        }
104        return i;
105    }
106
107    /**
108     * Reverses a byte[] array.  Reverses in-place (thus provided array is
109     * mutated), but also returns same for convenience.
110     *
111     * @param array to reverse (mutated in-place, but also returned for
112     *        convenience).
113     *
114     * @return the reversed array (mutated in-place, but also returned for
115     *        convenience).
116     * @since 1.5
117     */
118    public static byte[] reverse(final byte[] array) {
119        final int z = array.length - 1; // position of last element
120        for (int i = 0; i < array.length / 2; i++) {
121            final byte x = array[i];
122            array[i] = array[z - i];
123            array[z - i] = x;
124        }
125        return array;
126    }
127
128    /**
129     * Converts a BigInteger into a long, and blows up
130     * (NumberFormatException) if the BigInteger is too big.
131     *
132     * @param big BigInteger to convert.
133     * @return long representation of the BigInteger.
134     */
135    static long bigToLong(final BigInteger big) {
136        if (big.bitLength() <= 63) { // bitLength() doesn't count the sign bit.
137            return big.longValue();
138        }
139        throw new NumberFormatException("The BigInteger cannot fit inside a 64 bit java long: [" + big + "]");
140    }
141
142    /**
143     * <p>
144     * Converts a long into a BigInteger.  Negative numbers between -1 and
145     * -2^31 are treated as unsigned 32 bit (e.g., positive) integers.
146     * Negative numbers below -2^31 cause an IllegalArgumentException
147     * to be thrown.
148     * </p>
149     *
150     * @param l long to convert to BigInteger.
151     * @return BigInteger representation of the provided long.
152     */
153    static BigInteger longToBig(long l) {
154        if (l < Integer.MIN_VALUE) {
155            throw new IllegalArgumentException("Negative longs < -2^31 not permitted: [" + l + "]");
156        }
157        if (l < 0 && l >= Integer.MIN_VALUE) {
158            // If someone passes in a -2, they probably mean 4294967294
159            // (For example, Unix UID/GID's are 32 bit unsigned.)
160            l = ZipUtil.adjustToLong((int) l);
161        }
162        return BigInteger.valueOf(l);
163    }
164
165    /**
166     * Converts a signed byte into an unsigned integer representation
167     * (e.g., -1 becomes 255).
168     *
169     * @param b byte to convert to int
170     * @return int representation of the provided byte
171     * @since 1.5
172     */
173    public static int signedByteToUnsignedInt(final byte b) {
174        if (b >= 0) {
175            return b;
176        }
177        return 256 + b;
178    }
179
180    /**
181     * Converts an unsigned integer to a signed byte (e.g., 255 becomes -1).
182     *
183     * @param i integer to convert to byte
184     * @return byte representation of the provided int
185     * @throws IllegalArgumentException if the provided integer is not inside the range [0,255].
186     * @since 1.5
187     */
188    public static byte unsignedIntToSignedByte(final int i) {
189        if (i > 255 || i < 0) {
190            throw new IllegalArgumentException("Can only convert non-negative integers between [0,255] to byte: [" + i + "]");
191        }
192        if (i < 128) {
193            return (byte) i;
194        }
195        return (byte) (i - 256);
196    }
197
198    /**
199     * Convert a DOS date/time field to a Date object.
200     *
201     * @param zipDosTime contains the stored DOS time.
202     * @return a Date instance corresponding to the given time.
203     */
204    public static Date fromDosTime(final ZipLong zipDosTime) {
205        final long dosTime = zipDosTime.getValue();
206        return new Date(dosToJavaTime(dosTime));
207    }
208
209    /**
210     * Converts DOS time to Java time (number of milliseconds since
211     * epoch).
212     * @param dosTime time to convert
213     * @return converted time
214     */
215    public static long dosToJavaTime(final long dosTime) {
216        final Calendar cal = Calendar.getInstance();
217        // CheckStyle:MagicNumberCheck OFF - no point
218        cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980);
219        cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1);
220        cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f);
221        cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f);
222        cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f);
223        cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e);
224        cal.set(Calendar.MILLISECOND, 0);
225        // CheckStyle:MagicNumberCheck ON
226        return cal.getTime().getTime();
227    }
228
229    /**
230     * If the entry has Unicode*ExtraFields and the CRCs of the
231     * names/comments match those of the extra fields, transfer the
232     * known Unicode values from the extra field.
233     */
234    static void setNameAndCommentFromExtraFields(final ZipArchiveEntry ze,
235                                                 final byte[] originalNameBytes,
236                                                 final byte[] commentBytes) {
237        final ZipExtraField nameCandidate = ze.getExtraField(UnicodePathExtraField.UPATH_ID);
238        final UnicodePathExtraField name = nameCandidate instanceof UnicodePathExtraField
239            ? (UnicodePathExtraField) nameCandidate : null;
240        final String newName = getUnicodeStringIfOriginalMatches(name,
241                                                           originalNameBytes);
242        if (newName != null) {
243            ze.setName(newName);
244            ze.setNameSource(ZipArchiveEntry.NameSource.UNICODE_EXTRA_FIELD);
245        }
246
247        if (commentBytes != null && commentBytes.length > 0) {
248            final ZipExtraField cmtCandidate = ze.getExtraField(UnicodeCommentExtraField.UCOM_ID);
249            final UnicodeCommentExtraField cmt = cmtCandidate instanceof UnicodeCommentExtraField
250                ? (UnicodeCommentExtraField) cmtCandidate : null;
251            final String newComment =
252                getUnicodeStringIfOriginalMatches(cmt, commentBytes);
253            if (newComment != null) {
254                ze.setComment(newComment);
255                ze.setCommentSource(ZipArchiveEntry.CommentSource.UNICODE_EXTRA_FIELD);
256            }
257        }
258    }
259
260    /**
261     * If the stored CRC matches the one of the given name, return the
262     * Unicode name of the given field.
263     *
264     * <p>If the field is null or the CRCs don't match, return null
265     * instead.</p>
266     */
267    private static
268        String getUnicodeStringIfOriginalMatches(final AbstractUnicodeExtraField f,
269                                                 final byte[] orig) {
270        if (f != null) {
271            final CRC32 crc32 = new CRC32();
272            crc32.update(orig);
273            final long origCRC32 = crc32.getValue();
274
275            if (origCRC32 == f.getNameCRC32()) {
276                try {
277                    return ZipEncodingHelper
278                        .UTF8_ZIP_ENCODING.decode(f.getUnicodeName());
279                } catch (final IOException ex) {
280                    // UTF-8 unsupported?  should be impossible the
281                    // Unicode*ExtraField must contain some bad bytes
282                }
283            }
284        }
285        // TODO log this anywhere?
286        return null;
287    }
288
289    /**
290     * Create a copy of the given array - or return null if the
291     * argument is null.
292     */
293    static byte[] copy(final byte[] from) {
294        if (from != null) {
295            return Arrays.copyOf(from, from.length);
296        }
297        return null;
298    }
299
300    static void copy(final byte[] from, final byte[] to, final int offset) {
301        if (from != null) {
302            System.arraycopy(from, 0, to, offset, from.length);
303        }
304    }
305
306
307    /**
308     * Whether this library is able to read or write the given entry.
309     */
310    static boolean canHandleEntryData(final ZipArchiveEntry entry) {
311        return supportsEncryptionOf(entry) && supportsMethodOf(entry);
312    }
313
314    /**
315     * Whether this library supports the encryption used by the given
316     * entry.
317     *
318     * @return true if the entry isn't encrypted at all
319     */
320    private static boolean supportsEncryptionOf(final ZipArchiveEntry entry) {
321        return !entry.getGeneralPurposeBit().usesEncryption();
322    }
323
324    /**
325     * Whether this library supports the compression method used by
326     * the given entry.
327     *
328     * @return true if the compression method is supported
329     */
330    private static boolean supportsMethodOf(final ZipArchiveEntry entry) {
331        return entry.getMethod() == ZipEntry.STORED
332            || entry.getMethod() == ZipMethod.UNSHRINKING.getCode()
333            || entry.getMethod() == ZipMethod.IMPLODING.getCode()
334            || entry.getMethod() == ZipEntry.DEFLATED
335            || entry.getMethod() == ZipMethod.ENHANCED_DEFLATED.getCode()
336            || entry.getMethod() == ZipMethod.BZIP2.getCode();
337    }
338
339    /**
340     * Checks whether the entry requires features not (yet) supported
341     * by the library and throws an exception if it does.
342     */
343    static void checkRequestedFeatures(final ZipArchiveEntry ze)
344        throws UnsupportedZipFeatureException {
345        if (!supportsEncryptionOf(ze)) {
346            throw
347                new UnsupportedZipFeatureException(UnsupportedZipFeatureException
348                                                   .Feature.ENCRYPTION, ze);
349        }
350        if (!supportsMethodOf(ze)) {
351            final ZipMethod m = ZipMethod.getMethodByCode(ze.getMethod());
352            if (m == null) {
353                throw
354                    new UnsupportedZipFeatureException(UnsupportedZipFeatureException
355                                                       .Feature.METHOD, ze);
356            }
357            throw new UnsupportedZipFeatureException(m, ze);
358        }
359    }
360}