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      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 2152. Two variants are supported using the
     30  * encodeOptional constructor flag
     31  * </p>
     32  *
     33  * @see <a href="http://tools.ietf.org/html/rfc2152">RFC 2152< /a>
     34  * @author Jaap Beetstra
     35  */
     36 class UTF7Charset extends UTF7StyleCharset {
     37     private static final String BASE64_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     38             + "abcdefghijklmnopqrstuvwxyz" + "0123456789+/";
     39     private static final String SET_D = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'(),-./:?";
     40     private static final String SET_O = "!\"#$%&*;<=>@[]^_`{|}";
     41     private static final String RULE_3 = " \t\r\n";
     42     final String directlyEncoded;
     43 
     44     UTF7Charset(String name, String[] aliases, boolean includeOptional) {
     45         super(name, aliases, BASE64_ALPHABET, false);
     46         if (includeOptional)
     47             this.directlyEncoded = SET_D + SET_O + RULE_3;
     48         else
     49             this.directlyEncoded = SET_D + RULE_3;
     50     }
     51 
     52     /*
     53      * (non-Javadoc)
     54      * @see com.beetstra.jutf7.UTF7StyleCharset#canEncodeDirectly(char)
     55      */
     56     boolean canEncodeDirectly(char ch) {
     57         return directlyEncoded.indexOf(ch) >= 0;
     58     }
     59 
     60     /*
     61      * (non-Javadoc)
     62      * @see com.beetstra.jutf7.UTF7StyleCharset#shift()
     63      */
     64     byte shift() {
     65         return '+';
     66     }
     67 
     68     /*
     69      * (non-Javadoc)
     70      * @see com.beetstra.jutf7.UTF7StyleCharset#unshift()
     71      */
     72     byte unshift() {
     73         return '-';
     74     }
     75 }
     76