1/*
2 * Copyright (c) 2013, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package java.util.zip;
27
28import java.nio.file.attribute.FileTime;
29import java.security.AccessController;
30import java.security.PrivilegedAction;
31import java.time.Instant;
32import java.time.LocalDateTime;
33import java.time.ZoneId;
34import java.util.concurrent.TimeUnit;
35
36import static java.util.zip.ZipConstants.ENDHDR;
37
38class ZipUtils {
39
40    // used to adjust values between Windows and java epoch
41    private static final long WINDOWS_EPOCH_IN_MICROSECONDS = -11644473600000000L;
42
43    // used to indicate the corresponding windows time is not available
44    public static final long WINDOWS_TIME_NOT_AVAILABLE = Long.MIN_VALUE;
45
46    /**
47     * Converts Windows time (in microseconds, UTC/GMT) time to FileTime.
48     */
49    public static final FileTime winTimeToFileTime(long wtime) {
50        return FileTime.from(wtime / 10 + WINDOWS_EPOCH_IN_MICROSECONDS,
51                             TimeUnit.MICROSECONDS);
52    }
53
54    /**
55     * Converts FileTime to Windows time.
56     */
57    public static final long fileTimeToWinTime(FileTime ftime) {
58        return (ftime.to(TimeUnit.MICROSECONDS) - WINDOWS_EPOCH_IN_MICROSECONDS) * 10;
59    }
60
61    /**
62     * The upper bound of the 32-bit unix time, the "year 2038 problem".
63     */
64    public static final long UPPER_UNIXTIME_BOUND = 0x7fffffff;
65
66    /**
67     * Converts "standard Unix time"(in seconds, UTC/GMT) to FileTime
68     */
69    public static final FileTime unixTimeToFileTime(long utime) {
70        return FileTime.from(utime, TimeUnit.SECONDS);
71    }
72
73    /**
74     * Converts FileTime to "standard Unix time".
75     */
76    public static final long fileTimeToUnixTime(FileTime ftime) {
77        return ftime.to(TimeUnit.SECONDS);
78    }
79
80    /**
81     * Converts DOS time to Java time (number of milliseconds since epoch).
82     */
83    public static long dosToJavaTime(long dtime) {
84        int year;
85        int month;
86        int day;
87        int hour = (int) ((dtime >> 11) & 0x1f);
88        int minute = (int) ((dtime >> 5) & 0x3f);
89        int second = (int) ((dtime << 1) & 0x3e);
90        if ((dtime >> 16) == 0) {
91            // Interpret the 0 DOS date as 1979-11-30 for compatibility with
92            // other implementations.
93            year = 1979;
94            month = 11;
95            day = 30;
96        } else {
97            year = (int) (((dtime >> 25) & 0x7f) + 1980);
98            month = (int) ((dtime >> 21) & 0x0f);
99            day = (int) ((dtime >> 16) & 0x1f);
100        }
101        LocalDateTime ldt = LocalDateTime.of(year, month, day, hour, minute, second);
102        return TimeUnit.MILLISECONDS.convert(ldt.toEpochSecond(
103                ZoneId.systemDefault().getRules().getOffset(ldt)), TimeUnit.SECONDS);
104    }
105
106    /**
107     * Converts extended DOS time to Java time, where up to 1999 milliseconds
108     * might be encoded into the upper half of the returned long.
109     *
110     * @param xdostime the extended DOS time value
111     * @return milliseconds since epoch
112     */
113    public static long extendedDosToJavaTime(long xdostime) {
114        long time = dosToJavaTime(xdostime);
115        return time + (xdostime >> 32);
116    }
117
118    /**
119     * Converts Java time to DOS time.
120     */
121    private static long javaToDosTime(long time) {
122        Instant instant = Instant.ofEpochMilli(time);
123        LocalDateTime ldt = LocalDateTime.ofInstant(
124                instant, ZoneId.systemDefault());
125        int year = ldt.getYear() - 1980;
126        if (year < 0) {
127            return (1 << 21) | (1 << 16);
128        }
129        return (year << 25 |
130            ldt.getMonthValue() << 21 |
131            ldt.getDayOfMonth() << 16 |
132            ldt.getHour() << 11 |
133            ldt.getMinute() << 5 |
134            ldt.getSecond() >> 1) & 0xffffffffL;
135    }
136
137    /**
138     * Converts Java time to DOS time, encoding any milliseconds lost
139     * in the conversion into the upper half of the returned long.
140     *
141     * @param time milliseconds since epoch
142     * @return DOS time with 2s remainder encoded into upper half
143     */
144    public static long javaToExtendedDosTime(long time) {
145        if (time < 0) {
146            return ZipEntry.DOSTIME_BEFORE_1980;
147        }
148        long dostime = javaToDosTime(time);
149        return (dostime != ZipEntry.DOSTIME_BEFORE_1980)
150                ? dostime + ((time % 2000) << 32)
151                : ZipEntry.DOSTIME_BEFORE_1980;
152    }
153
154    /**
155     * Fetches unsigned 16-bit value from byte array at specified offset.
156     * The bytes are assumed to be in Intel (little-endian) byte order.
157     */
158    public static final int get16(byte b[], int off) {
159        return (b[off] & 0xff) | ((b[off + 1] & 0xff) << 8);
160    }
161
162    /**
163     * Fetches unsigned 32-bit value from byte array at specified offset.
164     * The bytes are assumed to be in Intel (little-endian) byte order.
165     */
166    public static final long get32(byte b[], int off) {
167        return (get16(b, off) | ((long)get16(b, off+2) << 16)) & 0xffffffffL;
168    }
169
170    /**
171     * Fetches signed 64-bit value from byte array at specified offset.
172     * The bytes are assumed to be in Intel (little-endian) byte order.
173     */
174    public static final long get64(byte b[], int off) {
175        return get32(b, off) | (get32(b, off+4) << 32);
176    }
177
178    /**
179     * Fetches signed 32-bit value from byte array at specified offset.
180     * The bytes are assumed to be in Intel (little-endian) byte order.
181     *
182     */
183    public static final int get32S(byte b[], int off) {
184        return (get16(b, off) | (get16(b, off+2) << 16));
185    }
186
187    // fields access methods
188    static final int CH(byte[] b, int n) {
189        return b[n] & 0xff ;
190    }
191
192    static final int SH(byte[] b, int n) {
193        return (b[n] & 0xff) | ((b[n + 1] & 0xff) << 8);
194    }
195
196    static final long LG(byte[] b, int n) {
197        return ((SH(b, n)) | (SH(b, n + 2) << 16)) & 0xffffffffL;
198    }
199
200    static final long LL(byte[] b, int n) {
201        return (LG(b, n)) | (LG(b, n + 4) << 32);
202    }
203
204    static final long GETSIG(byte[] b) {
205        return LG(b, 0);
206    }
207
208    // local file (LOC) header fields
209    static final long LOCSIG(byte[] b) { return LG(b, 0); } // signature
210    static final int  LOCVER(byte[] b) { return SH(b, 4); } // version needed to extract
211    static final int  LOCFLG(byte[] b) { return SH(b, 6); } // general purpose bit flags
212    static final int  LOCHOW(byte[] b) { return SH(b, 8); } // compression method
213    static final long LOCTIM(byte[] b) { return LG(b, 10);} // modification time
214    static final long LOCCRC(byte[] b) { return LG(b, 14);} // crc of uncompressed data
215    static final long LOCSIZ(byte[] b) { return LG(b, 18);} // compressed data size
216    static final long LOCLEN(byte[] b) { return LG(b, 22);} // uncompressed data size
217    static final int  LOCNAM(byte[] b) { return SH(b, 26);} // filename length
218    static final int  LOCEXT(byte[] b) { return SH(b, 28);} // extra field length
219
220    // extra local (EXT) header fields
221    static final long EXTCRC(byte[] b) { return LG(b, 4);}  // crc of uncompressed data
222    static final long EXTSIZ(byte[] b) { return LG(b, 8);}  // compressed size
223    static final long EXTLEN(byte[] b) { return LG(b, 12);} // uncompressed size
224
225    // end of central directory header (END) fields
226    static final int  ENDSUB(byte[] b) { return SH(b, 8); }  // number of entries on this disk
227    static final int  ENDTOT(byte[] b) { return SH(b, 10);}  // total number of entries
228    static final long ENDSIZ(byte[] b) { return LG(b, 12);}  // central directory size
229    static final long ENDOFF(byte[] b) { return LG(b, 16);}  // central directory offset
230    static final int  ENDCOM(byte[] b) { return SH(b, 20);}  // size of zip file comment
231    static final int  ENDCOM(byte[] b, int off) { return SH(b, off + 20);}
232
233    // zip64 end of central directory recoder fields
234    static final long ZIP64_ENDTOD(byte[] b) { return LL(b, 24);}  // total number of entries on disk
235    static final long ZIP64_ENDTOT(byte[] b) { return LL(b, 32);}  // total number of entries
236    static final long ZIP64_ENDSIZ(byte[] b) { return LL(b, 40);}  // central directory size
237    static final long ZIP64_ENDOFF(byte[] b) { return LL(b, 48);}  // central directory offset
238    static final long ZIP64_LOCOFF(byte[] b) { return LL(b, 8);}   // zip64 end offset
239
240    // central directory header (CEN) fields
241    static final long CENSIG(byte[] b, int pos) { return LG(b, pos + 0); }
242    static final int  CENVEM(byte[] b, int pos) { return SH(b, pos + 4); }
243    static final int  CENVER(byte[] b, int pos) { return SH(b, pos + 6); }
244    static final int  CENFLG(byte[] b, int pos) { return SH(b, pos + 8); }
245    static final int  CENHOW(byte[] b, int pos) { return SH(b, pos + 10);}
246    static final long CENTIM(byte[] b, int pos) { return LG(b, pos + 12);}
247    static final long CENCRC(byte[] b, int pos) { return LG(b, pos + 16);}
248    static final long CENSIZ(byte[] b, int pos) { return LG(b, pos + 20);}
249    static final long CENLEN(byte[] b, int pos) { return LG(b, pos + 24);}
250    static final int  CENNAM(byte[] b, int pos) { return SH(b, pos + 28);}
251    static final int  CENEXT(byte[] b, int pos) { return SH(b, pos + 30);}
252    static final int  CENCOM(byte[] b, int pos) { return SH(b, pos + 32);}
253    static final int  CENDSK(byte[] b, int pos) { return SH(b, pos + 34);}
254    static final int  CENATT(byte[] b, int pos) { return SH(b, pos + 36);}
255    static final long CENATX(byte[] b, int pos) { return LG(b, pos + 38);}
256    static final long CENOFF(byte[] b, int pos) { return LG(b, pos + 42);}
257
258    // The END header is followed by a variable length comment of size < 64k.
259    static final long END_MAXLEN = 0xFFFF + ENDHDR;
260    static final int READBLOCKSZ = 128;
261
262    /**
263     * Loads zip native library, if not already laoded
264     */
265    static void loadLibrary() {
266        SecurityManager sm = System.getSecurityManager();
267        if (sm == null) {
268            System.loadLibrary("zip");
269        } else {
270            PrivilegedAction<Void> pa = () -> { System.loadLibrary("zip"); return null; };
271            AccessController.doPrivileged(pa);
272        }
273    }
274}
275