1/*
2 * Copyright (c) 2015, 2016, 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 */
25package jdk.internal.jimage.decompressor;
26
27import java.io.ByteArrayOutputStream;
28import java.util.zip.Inflater;
29
30/**
31 *
32 * ZIP Decompressor
33 *
34 * @implNote This class needs to maintain JDK 8 source compatibility.
35 *
36 * It is used internally in the JDK to implement jimage/jrtfs access,
37 * but also compiled and delivered as part of the jrtfs.jar to support access
38 * to the jimage file provided by the shipped JDK by tools running on JDK 8.
39 */
40final class ZipDecompressor implements ResourceDecompressor {
41
42    @Override
43    public String getName() {
44        return ZipDecompressorFactory.NAME;
45    }
46
47    static byte[] decompress(byte[] bytesIn, int offset) throws Exception {
48        Inflater inflater = new Inflater();
49        inflater.setInput(bytesIn, offset, bytesIn.length - offset);
50        ByteArrayOutputStream stream = new ByteArrayOutputStream(bytesIn.length - offset);
51        byte[] buffer = new byte[1024];
52
53        while (!inflater.finished()) {
54            int count = inflater.inflate(buffer);
55            stream.write(buffer, 0, count);
56        }
57
58        stream.close();
59
60        byte[] bytesOut = stream.toByteArray();
61        inflater.end();
62
63        return bytesOut;
64    }
65
66    @Override
67    public byte[] decompress(StringsProvider reader, byte[] content, int offset,
68            long originalSize) throws Exception {
69        byte[] decompressed = decompress(content, offset);
70        return decompressed;
71    }
72}
73