forked from openjdk/jdk
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathAdler32.java
More file actions
142 lines (128 loc) · 4.48 KB
/
Copy pathAdler32.java
File metadata and controls
142 lines (128 loc) · 4.48 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
/*
* Copyright (c) 1996, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.util.zip;
import java.nio.ByteBuffer;
import sun.nio.ch.DirectBuffer;
import jdk.internal.HotSpotIntrinsicCandidate;
/**
* A class that can be used to compute the Adler-32 checksum of a data
* stream. An Adler-32 checksum is almost as reliable as a CRC-32 but
* can be computed much faster.
*
* <p> Passing a {@code null} argument to a method in this class will cause
* a {@link NullPointerException} to be thrown.</p>
*
* @author David Connelly
* @since 1.1
*/
public class Adler32 implements Checksum {
private int adler = 1;
/**
* Creates a new Adler32 object.
*/
public Adler32() {
}
/**
* Updates the checksum with the specified byte (the low eight
* bits of the argument b).
*/
@Override
public void update(int b) {
adler = update(adler, b);
}
/**
* Updates the checksum with the specified array of bytes.
*
* @throws ArrayIndexOutOfBoundsException
* if {@code off} is negative, or {@code len} is negative, or
* {@code off+len} is negative or greater than the length of
* the array {@code b}.
*/
@Override
public void update(byte[] b, int off, int len) {
if (b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || off > b.length - len) {
throw new ArrayIndexOutOfBoundsException();
}
adler = updateBytes(adler, b, off, len);
}
/**
* Updates the checksum with the bytes from the specified buffer.
*
* The checksum is updated with the remaining bytes in the buffer, starting
* at the buffer's position. Upon return, the buffer's position will be
* updated to its limit; its limit will not have been changed.
*
* @since 1.8
*/
@Override
public void update(ByteBuffer buffer) {
int pos = buffer.position();
int limit = buffer.limit();
assert (pos <= limit);
int rem = limit - pos;
if (rem <= 0)
return;
if (buffer instanceof DirectBuffer) {
adler = updateByteBuffer(adler, ((DirectBuffer)buffer).address(), pos, rem);
} else if (buffer.hasArray()) {
adler = updateBytes(adler, buffer.array(), pos + buffer.arrayOffset(), rem);
} else {
byte[] b = new byte[Math.min(buffer.remaining(), 4096)];
while (buffer.hasRemaining()) {
int length = Math.min(buffer.remaining(), b.length);
buffer.get(b, 0, length);
update(b, 0, length);
}
}
buffer.position(limit);
}
/**
* Resets the checksum to initial value.
*/
@Override
public void reset() {
adler = 1;
}
/**
* Returns the checksum value.
*/
@Override
public long getValue() {
return (long)adler & 0xffffffffL;
}
private static native int update(int adler, int b);
@HotSpotIntrinsicCandidate
private static native int updateBytes(int adler, byte[] b, int off,
int len);
@HotSpotIntrinsicCandidate
private static native int updateByteBuffer(int adler, long addr,
int off, int len);
static {
ZipUtils.loadLibrary();
}
}