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Java > Open Source Codes > com > quadcap > io > DotStuffOutputStream


1 package com.quadcap.io;
2
3 /* Copyright 1997 - 2003 Quadcap Software. All rights reserved.
4  *
5  * This software is distributed under the Quadcap Free Software License.
6  * This software may be used or modified for any purpose, personal or
7  * commercial. Open Source redistributions are permitted. Commercial
8  * redistribution of larger works derived from, or works which bundle
9  * this software requires a "Commercial Redistribution License"; see
10  * http://www.quadcap.com/purchase.
11  *
12  * Redistributions qualify as "Open Source" under one of the following terms:
13  *
14  * Redistributions are made at no charge beyond the reasonable cost of
15  * materials and delivery.
16  *
17  * Redistributions are accompanied by a copy of the Source Code or by an
18  * irrevocable offer to provide a copy of the Source Code for up to three
19  * years at the cost of materials and delivery. Such redistributions
20  * must allow further use, modification, and redistribution of the Source
21  * Code under substantially the same terms as this license.
22  *
23  * Redistributions of source code must retain the copyright notices as they
24  * appear in each source code file, these license terms, and the
25  * disclaimer/limitation of liability set forth as paragraph 6 below.
26  *
27  * Redistributions in binary form must reproduce this Copyright Notice,
28  * these license terms, and the disclaimer/limitation of liability set
29  * forth as paragraph 6 below, in the documentation and/or other materials
30  * provided with the distribution.
31  *
32  * The Software is provided on an "AS IS" basis. No warranty is
33  * provided that the Software is free of defects, or fit for a
34  * particular purpose.
35  *
36  * Limitation of Liability. Quadcap Software shall not be liable
37  * for any damages suffered by the Licensee or any third party resulting
38  * from use of the Software.
39  */
40
41 import java.io.*;
42
43 import com.quadcap.util.Debug;
44 import com.quadcap.util.Util;
45
46 /**
47  * A filter output stream that performs dot-stuffing.
48  *
49  * @author Stan Bailes
50  */
51
52 public class DotStuffOutputStream extends OutputStream {
53     OutputStream out;
54     
55     static final int INIT = 0;
56     static final int SEENCR = 1;
57     static final int SEENLF = 2;
58
59     static final byte CR = (byte)'\r';
60     static final byte LF = (byte)'\n';
61
62     static final byte[] endTag = { CR, LF, (byte)'.', CR, LF };
63     
64     int state = SEENLF;
65     
66     public DotStuffOutputStream(OutputStream os) {
67     this.out = os;
68     }
69
70     public void write(int b) throws IOException {
71     switch (state) {
72     case INIT:
73         if (b == CR) state = SEENCR;
74         break;
75     case SEENCR:
76         if (b == LF) state = SEENLF;
77         else if (b != CR) state = INIT;
78         break;
79     case SEENLF:
80         if (b == '.') {
81         out.write('.');
82         state = INIT;
83         } else if (b == CR) {
84         state = SEENCR;
85         } else {
86         state = INIT;
87         }
88         break;
89     }
90     out.write(b);
91     }
92
93     public void write(byte[] buf, int offset, int len) throws IOException {
94     for (int i = 0; i < len; i++) {
95         this.write(buf[i]);
96     }
97     }
98
99     public void writeFinal() throws IOException {
100     int start = 0;
101     int cnt = endTag.length - start;
102     out.write(endTag, start, cnt);
103     out.flush();
104     }
105 }
106
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