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
25package 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 */
36class ModifiedUTF7Charset extends UTF7StyleCharset {
37    private static final String MODIFIED_BASE64_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
38            + "abcdefghijklmnopqrstuvwxyz" + "0123456789+,";
39
40    ModifiedUTF7Charset(String name, String[] aliases) {
41        super(name, aliases, MODIFIED_BASE64_ALPHABET, true);
42    }
43
44    boolean canEncodeDirectly(char ch) {
45        if (ch == shift())
46            return false;
47        return ch >= 0x20 && ch <= 0x7E;
48    }
49
50    byte shift() {
51        return '&';
52    }
53
54    byte unshift() {
55        return '-';
56    }
57}
58