All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.sun.mail.imap.protocol.BASE64MailboxEncoder Maven / Gradle / Ivy

There is a newer version: 1.6.2
Show newest version
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2017 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://oss.oracle.com/licenses/CDDL+GPL-1.1
 * or LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.mail.imap.protocol;

import java.io.*;


/**
 * From RFC2060:
 *
 * 
 *
 * 5.1.3.  Mailbox International Naming Convention
 *
 *   By convention, international mailbox names are specified using a
 *   modified version of the UTF-7 encoding described in [UTF-7].  The
 *   purpose of these modifications is to correct the following problems
 *   with UTF-7:
 *
 *      1) UTF-7 uses the "+" character for shifting; this conflicts with
 *         the common use of "+" in mailbox names, in particular USENET
 *         newsgroup names.
 *
 *      2) UTF-7's encoding is BASE64 which uses the "/" character; this
 *         conflicts with the use of "/" as a popular hierarchy delimiter.
 *
 *      3) UTF-7 prohibits the unencoded usage of "\"; this conflicts with
 *         the use of "\" as a popular hierarchy delimiter.
 *
 *      4) UTF-7 prohibits the unencoded usage of "~"; this conflicts with
 *         the use of "~" in some servers as a home directory indicator.
 *
 *      5) UTF-7 permits multiple alternate forms to represent the same
 *         string; in particular, printable US-ASCII chararacters can be
 *         represented in encoded form.
 *
 *   In modified UTF-7, printable US-ASCII characters except for "&"
 *   represent themselves; that is, characters with octet values 0x20-0x25
 *   and 0x27-0x7e.  The character "&" (0x26) is represented by the two-
 *   octet sequence "&-".
 *
 *   All other characters (octet values 0x00-0x1f, 0x7f-0xff, and all
 *   Unicode 16-bit octets) are represented in modified BASE64, with a
 *   further modification from [UTF-7] that "," is used instead of "/".
 *   Modified BASE64 MUST NOT be used to represent any printing US-ASCII
 *   character which can represent itself.
 *
 *   "&" is used to shift to modified BASE64 and "-" to shift back to US-
 *   ASCII.  All names start in US-ASCII, and MUST end in US-ASCII (that
 *   is, a name that ends with a Unicode 16-bit octet MUST end with a "-
 *   ").
 *
 *   For example, here is a mailbox name which mixes English, Japanese,
 *   and Chinese text: ~peter/mail/&ZeVnLIqe-/&U,BTFw-
 *
 * 
* * This class will do the correct Encoding for the IMAP mailboxes. * * @author Christopher Cotton */ public class BASE64MailboxEncoder { protected byte[] buffer = new byte[4]; protected int bufsize = 0; protected boolean started = false; protected Writer out = null; public static String encode(String original) { BASE64MailboxEncoder base64stream = null; char origchars[] = original.toCharArray(); int length = origchars.length; boolean changedString = false; CharArrayWriter writer = new CharArrayWriter(length); // loop over all the chars for(int index = 0; index < length; index++) { char current = origchars[index]; // octets in the range 0x20-0x25,0x27-0x7e are themselves // 0x26 "&" is represented as "&-" if (current >= 0x20 && current <= 0x7e) { if (base64stream != null) { base64stream.flush(); } if (current == '&') { changedString = true; writer.write('&'); writer.write('-'); } else { writer.write(current); } } else { // use a B64MailboxEncoder to write out the other bytes // as a modified BASE64. The stream will write out // the beginning '&' and the ending '-' which is part // of every encoding. if (base64stream == null) { base64stream = new BASE64MailboxEncoder(writer); changedString = true; } base64stream.write(current); } } if (base64stream != null) { base64stream.flush(); } if (changedString) { return writer.toString(); } else { return original; } } /** * Create a BASE64 encoder * * @param what where to write the encoded name */ public BASE64MailboxEncoder(Writer what) { out = what; } public void write(int c) { try { // write out the initial character if this is the first time if (!started) { started = true; out.write('&'); } // we write each character as a 2 byte unicode character buffer[bufsize++] = (byte) (c >> 8); buffer[bufsize++] = (byte) (c & 0xff); if (bufsize >= 3) { encode(); bufsize -= 3; } } catch (IOException e) { //e.printStackTrace(); } } public void flush() { try { // flush any bytes we have if (bufsize > 0) { encode(); bufsize = 0; } // write the terminating character of the encoding if (started) { out.write('-'); started = false; } } catch (IOException e) { //e.printStackTrace(); } } protected void encode() throws IOException { byte a, b, c; if (bufsize == 1) { a = buffer[0]; b = 0; c = 0; out.write(pem_array[(a >>> 2) & 0x3F]); out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]); // no padding characters are written } else if (bufsize == 2) { a = buffer[0]; b = buffer[1]; c = 0; out.write(pem_array[(a >>> 2) & 0x3F]); out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]); out.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]); // no padding characters are written } else { a = buffer[0]; b = buffer[1]; c = buffer[2]; out.write(pem_array[(a >>> 2) & 0x3F]); out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]); out.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]); out.write(pem_array[c & 0x3F]); // copy back the extra byte if (bufsize == 4) buffer[0] = buffer[3]; } } private final static char pem_array[] = { 'A','B','C','D','E','F','G','H', // 0 'I','J','K','L','M','N','O','P', // 1 'Q','R','S','T','U','V','W','X', // 2 'Y','Z','a','b','c','d','e','f', // 3 'g','h','i','j','k','l','m','n', // 4 'o','p','q','r','s','t','u','v', // 5 'w','x','y','z','0','1','2','3', // 6 '4','5','6','7','8','9','+',',' // 7 }; }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy