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Java > Open Source Codes > org > columba > ristretto > coder > QuotedPrintableDecoderInputStream


1 /* ***** BEGIN LICENSE BLOCK *****
2  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
3  *
4  * The contents of this file are subject to the Mozilla Public License Version
5  * 1.1 (the "License"); you may not use this file except in compliance with
6  * the License. You may obtain a copy of the License at
7  * http://www.mozilla.org/MPL/
8  *
9  * Software distributed under the License is distributed on an "AS IS" basis,
10  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
11  * for the specific language governing rights and limitations under the
12  * License.
13  *
14  * The Original Code is Ristretto Mail API.
15  *
16  * The Initial Developers of the Original Code are
17  * Timo Stich and Frederik Dietz.
18  * Portions created by the Initial Developers are Copyright (C) 2004
19  * All Rights Reserved.
20  *
21  * Contributor(s):
22  *
23  * Alternatively, the contents of this file may be used under the terms of
24  * either the GNU General Public License Version 2 or later (the "GPL"), or
25  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
26  * in which case the provisions of the GPL or the LGPL are applicable instead
27  * of those above. If you wish to allow use of your version of this file only
28  * under the terms of either the GPL or the LGPL, and not to allow others to
29  * use your version of this file under the terms of the MPL, indicate your
30  * decision by deleting the provisions above and replace them with the notice
31  * and other provisions required by the GPL or the LGPL. If you do not delete
32  * the provisions above, a recipient may use your version of this file under
33  * the terms of any one of the MPL, the GPL or the LGPL.
34  *
35  * ***** END LICENSE BLOCK ***** */
36 package org.columba.ristretto.coder;
37
38 import java.io.FilterInputStream JavaDoc;
39 import java.io.IOException JavaDoc;
40 import java.io.InputStream JavaDoc;
41
42
43 /**
44  * FilterInputStream that decodes a quoted-printable encoded characterstream.
45  * <br>
46  * <b>RFC(s):</b> 2045
47  *
48  * @author Timo Stich <tstich@users.sourceforge.net>
49  */
50 public class QuotedPrintableDecoderInputStream extends FilterInputStream JavaDoc {
51     
52     /**
53      * Constructs a QuotedPrinatbleDecoderInputStream.
54      *
55      * @param arg0 the quoted-printable encoded characterstream
56      */
57     public QuotedPrintableDecoderInputStream(InputStream JavaDoc arg0) {
58         super(arg0);
59     }
60     
61     /**
62      * Read a quoted-printable pack wich is of the form
63      * =[2-digit hex-number] and decode it to one 8-bit value.
64      *
65      * @return number of characters decoded
66      * @throws IOException
67      */
68     private int readNextOctet() throws IOException JavaDoc {
69         int read = in.read();
70         if( read == -1) return -1;
71         
72         if( read == '=') {
73             int first = in.read();
74             switch( first ) {
75                 case('\r') : {
76                     in.read(); // read '\n'
77 return readNextOctet();
78                 }
79                 
80                 case('\n') : {
81                     return readNextOctet();
82                 }
83                 
84                 default : {
85                     int second = in.read();
86                     char[] number = { (char) first, (char) second };
87                     try {
88                         return Integer.parseInt( new String JavaDoc(number), 16);
89                     } catch (NumberFormatException JavaDoc e) {
90                         // Invalid QuotedPrintable Encoding
91 return '?';
92                     }
93                 }
94             }
95             
96         } else {
97             return read;
98         }
99     }
100     
101
102     /**
103      * @see java.io.InputStream#read()
104      */
105     public int read() throws IOException JavaDoc {
106         return readNextOctet();
107     }
108
109     /**
110      * @see java.io.InputStream#read(byte[], int, int)
111      */
112     public int read(byte[] arg0, int arg1, int arg2) throws IOException JavaDoc {
113         int next;
114         for( int i=0; i<arg2; i++) {
115             next = read();
116             if( next == -1 ) {
117                 if( i == 0 ) {
118                     return -1;
119                 } else {
120                     return i;
121                 }
122             }
123             arg0[arg1+i] = (byte) next;
124         }
125         return arg2;
126     }
127
128 }
129
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