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     */
018    package org.apache.commons.compress.archivers.zip;
019    
020    import java.io.IOException;
021    import java.util.Calendar;
022    import java.util.Date;
023    import java.util.zip.CRC32;
024    
025    /**
026     * Utility class for handling DOS and Java time conversions.
027     * @Immutable
028     */
029    public abstract class ZipUtil {
030        /**
031         * Smallest date/time ZIP can handle.
032         */
033        private static final byte[] DOS_TIME_MIN = ZipLong.getBytes(0x00002100L);
034    
035        /**
036         * Convert a Date object to a DOS date/time field.
037         * @param time the <code>Date</code> to convert
038         * @return the date as a <code>ZipLong</code>
039         */
040        public static ZipLong toDosTime(Date time) {
041            return new ZipLong(toDosTime(time.getTime()));
042        }
043    
044        /**
045         * Convert a Date object to a DOS date/time field.
046         *
047         * <p>Stolen from InfoZip's <code>fileio.c</code></p>
048         * @param t number of milliseconds since the epoch
049         * @return the date as a byte array
050         */
051        public static byte[] toDosTime(long t) {
052            Calendar c = Calendar.getInstance();
053            c.setTimeInMillis(t);
054    
055            int year = c.get(Calendar.YEAR);
056            if (year < 1980) {
057                return (byte[]) DOS_TIME_MIN.clone(); // stop callers from changing the array
058            }
059            int month = c.get(Calendar.MONTH) + 1;
060            long value =  ((year - 1980) << 25)
061                |         (month << 21)
062                |         (c.get(Calendar.DAY_OF_MONTH) << 16)
063                |         (c.get(Calendar.HOUR_OF_DAY) << 11)
064                |         (c.get(Calendar.MINUTE) << 5)
065                |         (c.get(Calendar.SECOND) >> 1);
066            return ZipLong.getBytes(value);
067        }
068    
069        /**
070         * Assumes a negative integer really is a positive integer that
071         * has wrapped around and re-creates the original value.
072         * @param i the value to treat as unsigned int.
073         * @return the unsigned int as a long.
074         */
075        public static long adjustToLong(int i) {
076            if (i < 0) {
077                return 2 * ((long) Integer.MAX_VALUE) + 2 + i;
078            } else {
079                return i;
080            }
081        }
082    
083        /**
084         * Convert a DOS date/time field to a Date object.
085         *
086         * @param zipDosTime contains the stored DOS time.
087         * @return a Date instance corresponding to the given time.
088         */
089        public static Date fromDosTime(ZipLong zipDosTime) {
090            long dosTime = zipDosTime.getValue();
091            return new Date(dosToJavaTime(dosTime));
092        }
093    
094        /**
095         * Converts DOS time to Java time (number of milliseconds since
096         * epoch).
097         */
098        public static long dosToJavaTime(long dosTime) {
099            Calendar cal = Calendar.getInstance();
100            // CheckStyle:MagicNumberCheck OFF - no point
101            cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980);
102            cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1);
103            cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f);
104            cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f);
105            cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f);
106            cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e);
107            // CheckStyle:MagicNumberCheck ON
108            return cal.getTime().getTime();
109        }
110    
111        /**
112         * If the entry has Unicode*ExtraFields and the CRCs of the
113         * names/comments match those of the extra fields, transfer the
114         * known Unicode values from the extra field.
115         */
116        static void setNameAndCommentFromExtraFields(ZipArchiveEntry ze,
117                                                     byte[] originalNameBytes,
118                                                     byte[] commentBytes) {
119            UnicodePathExtraField name = (UnicodePathExtraField)
120                ze.getExtraField(UnicodePathExtraField.UPATH_ID);
121            String originalName = ze.getName();
122            String newName = getUnicodeStringIfOriginalMatches(name,
123                                                               originalNameBytes);
124            if (newName != null && !originalName.equals(newName)) {
125                ze.setName(newName);
126            }
127    
128            if (commentBytes != null && commentBytes.length > 0) {
129                UnicodeCommentExtraField cmt = (UnicodeCommentExtraField)
130                    ze.getExtraField(UnicodeCommentExtraField.UCOM_ID);
131                String newComment =
132                    getUnicodeStringIfOriginalMatches(cmt, commentBytes);
133                if (newComment != null) {
134                    ze.setComment(newComment);
135                }
136            }
137        }
138    
139        /**
140         * If the stored CRC matches the one of the given name, return the
141         * Unicode name of the given field.
142         *
143         * <p>If the field is null or the CRCs don't match, return null
144         * instead.</p>
145         */
146        private static 
147            String getUnicodeStringIfOriginalMatches(AbstractUnicodeExtraField f,
148                                                     byte[] orig) {
149            if (f != null) {
150                CRC32 crc32 = new CRC32();
151                crc32.update(orig);
152                long origCRC32 = crc32.getValue();
153    
154                if (origCRC32 == f.getNameCRC32()) {
155                    try {
156                        return ZipEncodingHelper
157                            .UTF8_ZIP_ENCODING.decode(f.getUnicodeName());
158                    } catch (IOException ex) {
159                        // UTF-8 unsupported?  should be impossible the
160                        // Unicode*ExtraField must contain some bad bytes
161    
162                        // TODO log this anywhere?
163                        return null;
164                    }
165                }
166            }
167            return null;
168        }
169    
170    
171    }