Adler32.java revision a8ed084745590c5e4a0e8559b5821809d60fe242 
1/*
2 * Copyright (c) 1996, 2005, 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
28/* ----- BEGIN android -----
29import java.nio.ByteBuffer;
30import sun.nio.ch.DirectBuffer;
31----- END android ----- */
32
33/**
34 * A class that can be used to compute the Adler-32 checksum of a data
35 * stream. An Adler-32 checksum is almost as reliable as a CRC-32 but
36 * can be computed much faster.
37 *
38 * @see         Checksum
39 * @author      David Connelly
40 */
41public
42class Adler32 implements Checksum {
43    /* ----- BEGIN android -----
44    private int adler = 1;*/
45    private long adler = 1;
46    // ----- END android -----
47
48    /**
49     * Creates a new Adler32 object.
50     */
51    public Adler32() {
52    }
53
54    /**
55     * Updates the checksum with the specified byte (the low eight
56     * bits of the argument b).
57     *
58     * @param b the byte to update the checksum with
59     */
60    public void update(int b) {
61        /* ----- BEGIN android -----
62        adler = update(adler, b);*/
63        adler = updateByteImpl(b, adler);
64        // ----- END android -----
65    }
66
67    /**
68     * Updates the checksum with the specified array of bytes.
69     */
70    public void update(byte[] b, int off, int len) {
71        if (b == null) {
72            throw new NullPointerException();
73        }
74        if (off < 0 || len < 0 || off > b.length - len) {
75            throw new ArrayIndexOutOfBoundsException();
76        }
77        /* ----- BEGIN android -----
78        adler = updateBytes(adler, b, off, len);*/
79        adler = updateImpl(b, off, len, adler);
80        // ----- END android -----
81    }
82
83    /**
84     * Updates the checksum with the specified array of bytes.
85     *
86     * @param b the byte array to update the checksum with
87     */
88    public void update(byte[] b) {
89        /* ----- BEGIN android -----
90        adler = updateBytes(adler, b, 0, b.length);*/
91        update(b, 0, b.length);
92        // ----- END android -----
93    }
94
95    /**
96     * Updates the checksum with the bytes from the specified buffer.
97     *
98     * The checksum is updated using
99     * buffer.{@link java.nio.Buffer#remaining() remaining()}
100     * bytes starting at
101     * buffer.{@link java.nio.Buffer#position() position()}
102     * Upon return, the buffer's position will be updated to its
103     * limit; its limit will not have been changed.
104     *
105     * @param buffer the ByteBuffer to update the checksum with
106     */
107    /* ----- BEGIN android -----
108    private void update(ByteBuffer buffer) {
109        int pos = buffer.position();
110        int limit = buffer.limit();
111        assert (pos <= limit);
112        int rem = limit - pos;
113        if (rem <= 0)
114            return;
115        if (buffer instanceof DirectBuffer) {
116            adler = updateByteBuffer(adler, ((DirectBuffer)buffer).address(), pos, rem);
117        } else if (buffer.hasArray()) {
118            adler = updateBytes(adler, buffer.array(), pos + buffer.arrayOffset(), rem);
119        } else {
120            byte[] b = new byte[rem];
121            buffer.get(b);
122            adler = updateBytes(adler, b, 0, b.length);
123        }
124        buffer.position(limit);
125    }
126    ----- END android ----- */
127
128    /**
129     * Resets the checksum to initial value.
130     */
131    public void reset() {
132        adler = 1;
133    }
134
135    /**
136     * Returns the checksum value.
137     */
138    public long getValue() {
139        /* ----- BEGIN android -----
140        return (long)adler & 0xffffffffL;*/
141        return adler;
142        // ----- END android -----
143    }
144
145    /* ----- BEGIN android -----
146    // Set up JavaUtilZipAccess in SharedSecrets
147    static {
148       sun.misc.SharedSecrets.setJavaUtilZipAccess(new sun.misc.JavaUtilZipAccess() {
149           public void update(Adler32 adler32, ByteBuffer buf) {
150               adler32.update(buf);
151           }
152        });
153    }
154
155    private native static int update(int adler, int b);
156    private native static int updateBytes(int adler, byte[] b, int off,
157                                          int len);
158    private native static int updateByteBuffer(int adler, long addr,
159                                               int off, int len);*/
160    private native long updateImpl(byte[] buf, int offset, int byteCount, long adler1);
161
162    private native long updateByteImpl(int val, long adler1);
163    // ----- END android -----
164
165}
166