1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17/* Apache Harmony HEADER because the code in this class comes mostly from ZipFile, ZipEntry and
18 * ZipConstants from android libcore.
19 */
20
21package android.support.multidex;
22
23import java.io.IOException;
24import java.nio.ByteBuffer;
25import java.nio.charset.Charset;
26import java.util.Calendar;
27import java.util.GregorianCalendar;
28import java.util.zip.ZipEntry;
29import java.util.zip.ZipException;
30
31class ZipEntryReader {
32    static final Charset UTF_8 = Charset.forName("UTF-8");
33   /**
34     * General Purpose Bit Flags, Bit 0.
35     * If set, indicates that the file is encrypted.
36     */
37    private static final int GPBF_ENCRYPTED_FLAG = 1 << 0;
38
39    /**
40     * Supported General Purpose Bit Flags Mask.
41     * Bit mask of bits not supported.
42     * Note: The only bit that we will enforce at this time
43     * is the encrypted bit. Although other bits are not supported,
44     * we must not enforce them as this could break some legitimate
45     * use cases (See http://b/8617715).
46     */
47    private static final int GPBF_UNSUPPORTED_MASK = GPBF_ENCRYPTED_FLAG;
48    private static final long CENSIG = 0x2014b50;
49
50    static ZipEntry readEntry(ByteBuffer in) throws IOException {
51
52        int sig = in.getInt();
53        if (sig != CENSIG) {
54             throw new ZipException("Central Directory Entry not found");
55        }
56
57        in.position(8);
58        int gpbf = in.getShort() & 0xffff;
59
60        if ((gpbf & GPBF_UNSUPPORTED_MASK) != 0) {
61            throw new ZipException("Invalid General Purpose Bit Flag: " + gpbf);
62        }
63
64        int compressionMethod = in.getShort() & 0xffff;
65        int time = in.getShort() & 0xffff;
66        int modDate = in.getShort() & 0xffff;
67
68        // These are 32-bit values in the file, but 64-bit fields in this object.
69        long crc = ((long) in.getInt()) & 0xffffffffL;
70        long compressedSize = ((long) in.getInt()) & 0xffffffffL;
71        long size = ((long) in.getInt()) & 0xffffffffL;
72
73        int nameLength = in.getShort() & 0xffff;
74        int extraLength = in.getShort() & 0xffff;
75        int commentByteCount = in.getShort() & 0xffff;
76
77        // This is a 32-bit value in the file, but a 64-bit field in this object.
78        in.position(42);
79        long localHeaderRelOffset = ((long) in.getInt()) & 0xffffffffL;
80
81        byte[] nameBytes = new byte[nameLength];
82        in.get(nameBytes, 0, nameBytes.length);
83        String name = new String(nameBytes, 0, nameBytes.length, UTF_8);
84
85        ZipEntry entry = new ZipEntry(name);
86        entry.setMethod(compressionMethod);
87        entry.setTime(getTime(time, modDate));
88
89        entry.setCrc(crc);
90        entry.setCompressedSize(compressedSize);
91        entry.setSize(size);
92
93        // The RI has always assumed UTF-8. (If GPBF_UTF8_FLAG isn't set, the encoding is
94        // actually IBM-437.)
95        if (commentByteCount > 0) {
96            byte[] commentBytes = new byte[commentByteCount];
97            in.get(commentBytes, 0, commentByteCount);
98            entry.setComment(new String(commentBytes, 0, commentBytes.length, UTF_8));
99        }
100
101        if (extraLength > 0) {
102            byte[] extra = new byte[extraLength];
103            in.get(extra, 0, extraLength);
104            entry.setExtra(extra);
105        }
106
107        return entry;
108
109    }
110
111    private static long getTime(int time, int modDate) {
112        GregorianCalendar cal = new GregorianCalendar();
113        cal.set(Calendar.MILLISECOND, 0);
114        cal.set(1980 + ((modDate >> 9) & 0x7f), ((modDate >> 5) & 0xf) - 1,
115                modDate & 0x1f, (time >> 11) & 0x1f, (time >> 5) & 0x3f,
116                (time & 0x1f) << 1);
117        return cal.getTime().getTime();
118    }
119
120}
121