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2 * Licensed to the Apache Software Foundation (ASF) under one *
3 * or more contributor license agreements. See the NOTICE file *
4 * distributed with this work for additional information *
5 * regarding copyright ownership. The ASF licenses this file *
6 * to you under the Apache License, Version 2.0 (the *
7 * "License"); you may not use this file except in compliance *
8 * with the License. You may obtain a copy of the License at *
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10 * http://www.apache.org/licenses/LICENSE-2.0 *
11 * *
12 * Unless required by applicable law or agreed to in writing, *
13 * software distributed under the License is distributed on an *
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
15 * KIND, either express or implied. See the License for the *
16 * specific language governing permissions and limitations *
17 * under the License. *
18 ****************************************************************/
19
20 package org.apache.james.jdkim.canon;
21
22 import java.io.FilterOutputStream;
23 import java.io.IOException;
24 import java.io.OutputStream;
25 import java.security.MessageDigest;
26
27 /**
28 * DigestOutputStream is used as a filter stream or as the ending stream in
29 * order to calculate a digest of a stream.
30 */
31 public class DigestOutputStream extends FilterOutputStream {
32
33 private MessageDigest md;
34
35 public DigestOutputStream(MessageDigest md) {
36 this(md, null);
37 }
38
39 public DigestOutputStream(MessageDigest md, OutputStream out) {
40 super(out);
41 this.md = md;
42 }
43
44 public void write(int arg0) throws IOException {
45 md.update((byte) arg0);
46 if (out != null)
47 out.write(arg0);
48 }
49
50 public void write(byte[] b, int off, int len) throws IOException {
51 md.update(b, off, len);
52 if (out != null)
53 out.write(b, off, len);
54 }
55
56 public void close() throws IOException {
57 if (out != null)
58 super.close();
59 }
60
61 public void flush() throws IOException {
62 if (out != null)
63 super.flush();
64 }
65
66 public void write(byte[] b) throws IOException {
67 md.update(b);
68 if (out != null)
69 out.write(b);
70 }
71
72 /**
73 * @return the stream digest as a byte array
74 */
75 public byte[] getDigest() {
76 return md.digest();
77 }
78
79 }