1 /* ====================================================================
2  * Copyright (c) 2006 J.T. Beetstra
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining
5  * a copy of this software and associated documentation files (the
6  * "Software"), to deal in the Software without restriction, including
7  * without limitation the rights to use, copy, modify, merge, publish,
8  * distribute, sublicense, and/or sell copies of the Software, and to
9  * permit persons to whom the Software is furnished to do so, subject to
10  * the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be
13  * included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19  * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22  * ====================================================================
23  */
24 
25 package com.beetstra.jutf7;
26 
27 /**
28  * <p>
29  * The character set specified in RFC 3501 to use for IMAP4rev1 mailbox name
30  * encoding.
31  * </p>
32  *
33  * @see <a href="http://tools.ietf.org/html/rfc3501">RFC 3501< /a>
34  * @author Jaap Beetstra
35  */
36 class ModifiedUTF7Charset extends UTF7StyleCharset {
37     private static final String MODIFIED_BASE64_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
38             + "abcdefghijklmnopqrstuvwxyz" + "0123456789+,";
39 
ModifiedUTF7Charset(String name, String[] aliases)40     ModifiedUTF7Charset(String name, String[] aliases) {
41         super(name, aliases, MODIFIED_BASE64_ALPHABET, true);
42     }
43 
canEncodeDirectly(char ch)44     boolean canEncodeDirectly(char ch) {
45         if (ch == shift())
46             return false;
47         return ch >= 0x20 && ch <= 0x7E;
48     }
49 
shift()50     byte shift() {
51         return '&';
52     }
53 
unshift()54     byte unshift() {
55         return '-';
56     }
57 }
58