627 lines
22 KiB
Java
627 lines
22 KiB
Java
/****************************************************************
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* Licensed to the Apache Software Foundation (ASF) under one *
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* or more contributor license agreements. See the NOTICE file *
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* distributed with this work for additional information *
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* regarding copyright ownership. The ASF licenses this file *
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* to you under the Apache License, Version 2.0 (the *
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* "License"); you may not use this file except in compliance *
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* with the License. You may obtain a copy of the License at *
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* *
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* http://www.apache.org/licenses/LICENSE-2.0 *
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* *
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* Unless required by applicable law or agreed to in writing, *
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* software distributed under the License is distributed on an *
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
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* KIND, either express or implied. See the License for the *
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* specific language governing permissions and limitations *
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* under the License. *
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****************************************************************/
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package org.apache.james.mime4j.codec;
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import java.nio.ByteBuffer;
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import java.nio.charset.Charset;
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import java.util.BitSet;
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import java.util.Locale;
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import org.apache.james.mime4j.util.CharsetUtil;
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/**
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* ANDROID: THIS CLASS IS COPIED FROM A NEWER VERSION OF MIME4J
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*/
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/**
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* Static methods for encoding header field values. This includes encoded-words
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* as defined in <a href='http://www.faqs.org/rfcs/rfc2047.html'>RFC 2047</a>
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* or display-names of an e-mail address, for example.
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*
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*/
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public class EncoderUtil {
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// This array is a lookup table that translates 6-bit positive integer index
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// values into their "Base64 Alphabet" equivalents as specified in Table 1
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// of RFC 2045.
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// ANDROID: THIS TABLE IS COPIED FROM BASE64OUTPUTSTREAM
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static final byte[] BASE64_TABLE = { 'A', 'B', 'C', 'D', 'E', 'F',
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'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S',
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'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
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'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
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't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5',
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'6', '7', '8', '9', '+', '/' };
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// Byte used to pad output.
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private static final byte BASE64_PAD = '=';
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private static final BitSet Q_REGULAR_CHARS = initChars("=_?");
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private static final BitSet Q_RESTRICTED_CHARS = initChars("=_?\"#$%&'(),.:;<>@[\\]^`{|}~");
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private static final int MAX_USED_CHARACTERS = 50;
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private static final String ENC_WORD_PREFIX = "=?";
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private static final String ENC_WORD_SUFFIX = "?=";
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private static final int ENCODED_WORD_MAX_LENGTH = 75; // RFC 2047
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private static final BitSet TOKEN_CHARS = initChars("()<>@,;:\\\"/[]?=");
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private static final BitSet ATEXT_CHARS = initChars("()<>@.,;:\\\"[]");
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private static BitSet initChars(String specials) {
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BitSet bs = new BitSet(128);
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for (char ch = 33; ch < 127; ch++) {
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if (specials.indexOf(ch) == -1) {
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bs.set(ch);
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}
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}
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return bs;
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}
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/**
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* Selects one of the two encodings specified in RFC 2047.
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*/
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public enum Encoding {
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/** The B encoding (identical to base64 defined in RFC 2045). */
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B,
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/** The Q encoding (similar to quoted-printable defined in RFC 2045). */
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Q
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}
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/**
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* Indicates the intended usage of an encoded word.
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*/
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public enum Usage {
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/**
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* Encoded word is used to replace a 'text' token in any Subject or
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* Comments header field.
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*/
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TEXT_TOKEN,
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/**
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* Encoded word is used to replace a 'word' entity within a 'phrase',
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* for example, one that precedes an address in a From, To, or Cc
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* header.
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*/
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WORD_ENTITY
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}
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private EncoderUtil() {
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}
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/**
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* Encodes the display-name portion of an address. See <a
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* href='http://www.faqs.org/rfcs/rfc5322.html'>RFC 5322</a> section 3.4
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* and <a href='http://www.faqs.org/rfcs/rfc2047.html'>RFC 2047</a> section
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* 5.3. The specified string should not be folded.
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*
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* @param displayName
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* display-name to encode.
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* @return encoded display-name.
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*/
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public static String encodeAddressDisplayName(String displayName) {
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// display-name = phrase
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// phrase = 1*( encoded-word / word )
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// word = atom / quoted-string
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// atom = [CFWS] 1*atext [CFWS]
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// CFWS = comment or folding white space
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if (isAtomPhrase(displayName)) {
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return displayName;
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} else if (hasToBeEncoded(displayName, 0)) {
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return encodeEncodedWord(displayName, Usage.WORD_ENTITY);
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} else {
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return quote(displayName);
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}
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}
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/**
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* Encodes the local part of an address specification as described in RFC
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* 5322 section 3.4.1. Leading and trailing CFWS should have been removed
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* before calling this method. The specified string should not contain any
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* illegal (control or non-ASCII) characters.
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*
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* @param localPart
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* the local part to encode
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* @return the encoded local part.
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*/
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public static String encodeAddressLocalPart(String localPart) {
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// local-part = dot-atom / quoted-string
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// dot-atom = [CFWS] dot-atom-text [CFWS]
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// CFWS = comment or folding white space
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if (isDotAtomText(localPart)) {
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return localPart;
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} else {
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return quote(localPart);
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}
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}
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/**
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* Encodes the specified strings into a header parameter as described in RFC
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* 2045 section 5.1 and RFC 2183 section 2. The specified strings should not
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* contain any illegal (control or non-ASCII) characters.
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*
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* @param name
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* parameter name.
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* @param value
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* parameter value.
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* @return encoded result.
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*/
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public static String encodeHeaderParameter(String name, String value) {
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name = name.toLowerCase(Locale.US);
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// value := token / quoted-string
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if (isToken(value)) {
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return name + "=" + value;
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} else {
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return name + "=" + quote(value);
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}
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}
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/**
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* Shortcut method that encodes the specified text into an encoded-word if
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* the text has to be encoded.
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*
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* @param text
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* text to encode.
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* @param usage
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* whether the encoded-word is to be used to replace a text token
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* or a word entity (see RFC 822).
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* @param usedCharacters
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* number of characters already used up (<code>0 <= usedCharacters <= 50</code>).
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* @return the specified text if encoding is not necessary or an encoded
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* word or a sequence of encoded words otherwise.
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*/
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public static String encodeIfNecessary(String text, Usage usage,
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int usedCharacters) {
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if (hasToBeEncoded(text, usedCharacters))
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return encodeEncodedWord(text, usage, usedCharacters);
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else
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return text;
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}
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/**
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* Determines if the specified string has to encoded into an encoded-word.
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* Returns <code>true</code> if the text contains characters that don't
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* fall into the printable ASCII character set or if the text contains a
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* 'word' (sequence of non-whitespace characters) longer than 77 characters
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* (including characters already used up in the line).
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*
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* @param text
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* text to analyze.
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* @param usedCharacters
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* number of characters already used up (<code>0 <= usedCharacters <= 50</code>).
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* @return <code>true</code> if the specified text has to be encoded into
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* an encoded-word, <code>false</code> otherwise.
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*/
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public static boolean hasToBeEncoded(String text, int usedCharacters) {
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if (text == null)
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throw new IllegalArgumentException();
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if (usedCharacters < 0 || usedCharacters > MAX_USED_CHARACTERS)
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throw new IllegalArgumentException();
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int nonWhiteSpaceCount = usedCharacters;
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for (int idx = 0; idx < text.length(); idx++) {
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char ch = text.charAt(idx);
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if (ch == '\t' || ch == ' ') {
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nonWhiteSpaceCount = 0;
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} else {
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nonWhiteSpaceCount++;
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if (nonWhiteSpaceCount > 77) {
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// Line cannot be folded into multiple lines with no more
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// than 78 characters each. Encoding as encoded-words makes
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// that possible. One character has to be reserved for
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// folding white space; that leaves 77 characters.
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return true;
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}
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if (ch < 32 || ch >= 127) {
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// non-printable ascii character has to be encoded
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return true;
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}
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}
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}
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return false;
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}
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/**
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* Encodes the specified text into an encoded word or a sequence of encoded
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* words separated by space. The text is separated into a sequence of
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* encoded words if it does not fit in a single one.
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* <p>
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* The charset to encode the specified text into a byte array and the
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* encoding to use for the encoded-word are detected automatically.
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* <p>
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* This method assumes that zero characters have already been used up in the
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* current line.
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*
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* @param text
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* text to encode.
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* @param usage
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* whether the encoded-word is to be used to replace a text token
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* or a word entity (see RFC 822).
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* @return the encoded word (or sequence of encoded words if the given text
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* does not fit in a single encoded word).
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* @see #hasToBeEncoded(String, int)
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*/
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public static String encodeEncodedWord(String text, Usage usage) {
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return encodeEncodedWord(text, usage, 0, null, null);
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}
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/**
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* Encodes the specified text into an encoded word or a sequence of encoded
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* words separated by space. The text is separated into a sequence of
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* encoded words if it does not fit in a single one.
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* <p>
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* The charset to encode the specified text into a byte array and the
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* encoding to use for the encoded-word are detected automatically.
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*
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* @param text
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* text to encode.
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* @param usage
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* whether the encoded-word is to be used to replace a text token
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* or a word entity (see RFC 822).
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* @param usedCharacters
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* number of characters already used up (<code>0 <= usedCharacters <= 50</code>).
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* @return the encoded word (or sequence of encoded words if the given text
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* does not fit in a single encoded word).
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* @see #hasToBeEncoded(String, int)
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*/
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public static String encodeEncodedWord(String text, Usage usage,
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int usedCharacters) {
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return encodeEncodedWord(text, usage, usedCharacters, null, null);
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}
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/**
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* Encodes the specified text into an encoded word or a sequence of encoded
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* words separated by space. The text is separated into a sequence of
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* encoded words if it does not fit in a single one.
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*
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* @param text
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* text to encode.
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* @param usage
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* whether the encoded-word is to be used to replace a text token
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* or a word entity (see RFC 822).
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* @param usedCharacters
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* number of characters already used up (<code>0 <= usedCharacters <= 50</code>).
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* @param charset
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* the Java charset that should be used to encode the specified
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* string into a byte array. A suitable charset is detected
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* automatically if this parameter is <code>null</code>.
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* @param encoding
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* the encoding to use for the encoded-word (either B or Q). A
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* suitable encoding is automatically chosen if this parameter is
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* <code>null</code>.
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* @return the encoded word (or sequence of encoded words if the given text
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* does not fit in a single encoded word).
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* @see #hasToBeEncoded(String, int)
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*/
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public static String encodeEncodedWord(String text, Usage usage,
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int usedCharacters, Charset charset, Encoding encoding) {
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if (text == null)
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throw new IllegalArgumentException();
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if (usedCharacters < 0 || usedCharacters > MAX_USED_CHARACTERS)
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throw new IllegalArgumentException();
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if (charset == null)
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charset = determineCharset(text);
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String mimeCharset = CharsetUtil.toMimeCharset(charset.name());
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if (mimeCharset == null) {
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// cannot happen if charset was originally null
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throw new IllegalArgumentException("Unsupported charset");
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}
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byte[] bytes = encode(text, charset);
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if (encoding == null)
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encoding = determineEncoding(bytes, usage);
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if (encoding == Encoding.B) {
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String prefix = ENC_WORD_PREFIX + mimeCharset + "?B?";
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return encodeB(prefix, text, usedCharacters, charset, bytes);
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} else {
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String prefix = ENC_WORD_PREFIX + mimeCharset + "?Q?";
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return encodeQ(prefix, text, usage, usedCharacters, charset, bytes);
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}
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}
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/**
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* Encodes the specified byte array using the B encoding defined in RFC
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* 2047.
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*
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* @param bytes
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* byte array to encode.
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* @return encoded string.
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*/
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public static String encodeB(byte[] bytes) {
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StringBuilder sb = new StringBuilder();
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int idx = 0;
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final int end = bytes.length;
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for (; idx < end - 2; idx += 3) {
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int data = (bytes[idx] & 0xff) << 16 | (bytes[idx + 1] & 0xff) << 8
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| bytes[idx + 2] & 0xff;
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sb.append((char) BASE64_TABLE[data >> 18 & 0x3f]);
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sb.append((char) BASE64_TABLE[data >> 12 & 0x3f]);
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sb.append((char) BASE64_TABLE[data >> 6 & 0x3f]);
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sb.append((char) BASE64_TABLE[data & 0x3f]);
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}
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if (idx == end - 2) {
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int data = (bytes[idx] & 0xff) << 16 | (bytes[idx + 1] & 0xff) << 8;
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sb.append((char) BASE64_TABLE[data >> 18 & 0x3f]);
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sb.append((char) BASE64_TABLE[data >> 12 & 0x3f]);
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sb.append((char) BASE64_TABLE[data >> 6 & 0x3f]);
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sb.append((char) BASE64_PAD);
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} else if (idx == end - 1) {
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int data = (bytes[idx] & 0xff) << 16;
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sb.append((char) BASE64_TABLE[data >> 18 & 0x3f]);
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sb.append((char) BASE64_TABLE[data >> 12 & 0x3f]);
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sb.append((char) BASE64_PAD);
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sb.append((char) BASE64_PAD);
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}
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return sb.toString();
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}
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/**
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* Encodes the specified byte array using the Q encoding defined in RFC
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* 2047.
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*
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* @param bytes
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* byte array to encode.
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* @param usage
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* whether the encoded-word is to be used to replace a text token
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* or a word entity (see RFC 822).
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* @return encoded string.
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*/
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public static String encodeQ(byte[] bytes, Usage usage) {
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BitSet qChars = usage == Usage.TEXT_TOKEN ? Q_REGULAR_CHARS
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: Q_RESTRICTED_CHARS;
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StringBuilder sb = new StringBuilder();
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final int end = bytes.length;
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for (int idx = 0; idx < end; idx++) {
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int v = bytes[idx] & 0xff;
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if (v == 32) {
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sb.append('_');
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} else if (!qChars.get(v)) {
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sb.append('=');
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sb.append(hexDigit(v >>> 4));
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sb.append(hexDigit(v & 0xf));
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} else {
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sb.append((char) v);
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}
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}
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return sb.toString();
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}
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/**
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* Tests whether the specified string is a token as defined in RFC 2045
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* section 5.1.
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*
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* @param str
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* string to test.
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* @return <code>true</code> if the specified string is a RFC 2045 token,
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* <code>false</code> otherwise.
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*/
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public static boolean isToken(String str) {
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// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs, or tspecials>
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// tspecials := "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "\" /
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// <"> / "/" / "[" / "]" / "?" / "="
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// CTL := 0.- 31., 127.
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final int length = str.length();
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if (length == 0)
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return false;
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for (int idx = 0; idx < length; idx++) {
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char ch = str.charAt(idx);
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if (!TOKEN_CHARS.get(ch))
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return false;
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}
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return true;
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}
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private static boolean isAtomPhrase(String str) {
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// atom = [CFWS] 1*atext [CFWS]
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boolean containsAText = false;
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final int length = str.length();
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for (int idx = 0; idx < length; idx++) {
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char ch = str.charAt(idx);
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if (ATEXT_CHARS.get(ch)) {
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containsAText = true;
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} else if (!CharsetUtil.isWhitespace(ch)) {
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return false;
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}
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}
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return containsAText;
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}
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// RFC 5322 section 3.2.3
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private static boolean isDotAtomText(String str) {
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// dot-atom-text = 1*atext *("." 1*atext)
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// atext = ALPHA / DIGIT / "!" / "#" / "$" / "%" / "&" / "'" / "*" /
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// "+" / "-" / "/" / "=" / "?" / "^" / "_" / "`" / "{" / "|" / "}" / "~"
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char prev = '.';
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final int length = str.length();
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if (length == 0)
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return false;
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for (int idx = 0; idx < length; idx++) {
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char ch = str.charAt(idx);
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if (ch == '.') {
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if (prev == '.' || idx == length - 1)
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return false;
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} else {
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if (!ATEXT_CHARS.get(ch))
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return false;
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}
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prev = ch;
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}
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return true;
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}
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// RFC 5322 section 3.2.4
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private static String quote(String str) {
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// quoted-string = [CFWS] DQUOTE *([FWS] qcontent) [FWS] DQUOTE [CFWS]
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// qcontent = qtext / quoted-pair
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// qtext = %d33 / %d35-91 / %d93-126
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// quoted-pair = ("\" (VCHAR / WSP))
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// VCHAR = %x21-7E
|
|
// DQUOTE = %x22
|
|
|
|
String escaped = str.replaceAll("[\\\\\"]", "\\\\$0");
|
|
return "\"" + escaped + "\"";
|
|
}
|
|
|
|
private static String encodeB(String prefix, String text,
|
|
int usedCharacters, Charset charset, byte[] bytes) {
|
|
int encodedLength = bEncodedLength(bytes);
|
|
|
|
int totalLength = prefix.length() + encodedLength
|
|
+ ENC_WORD_SUFFIX.length();
|
|
if (totalLength <= ENCODED_WORD_MAX_LENGTH - usedCharacters) {
|
|
return prefix + encodeB(bytes) + ENC_WORD_SUFFIX;
|
|
} else {
|
|
String part1 = text.substring(0, text.length() / 2);
|
|
byte[] bytes1 = encode(part1, charset);
|
|
String word1 = encodeB(prefix, part1, usedCharacters, charset,
|
|
bytes1);
|
|
|
|
String part2 = text.substring(text.length() / 2);
|
|
byte[] bytes2 = encode(part2, charset);
|
|
String word2 = encodeB(prefix, part2, 0, charset, bytes2);
|
|
|
|
return word1 + " " + word2;
|
|
}
|
|
}
|
|
|
|
private static int bEncodedLength(byte[] bytes) {
|
|
return (bytes.length + 2) / 3 * 4;
|
|
}
|
|
|
|
private static String encodeQ(String prefix, String text, Usage usage,
|
|
int usedCharacters, Charset charset, byte[] bytes) {
|
|
int encodedLength = qEncodedLength(bytes, usage);
|
|
|
|
int totalLength = prefix.length() + encodedLength
|
|
+ ENC_WORD_SUFFIX.length();
|
|
if (totalLength <= ENCODED_WORD_MAX_LENGTH - usedCharacters) {
|
|
return prefix + encodeQ(bytes, usage) + ENC_WORD_SUFFIX;
|
|
} else {
|
|
String part1 = text.substring(0, text.length() / 2);
|
|
byte[] bytes1 = encode(part1, charset);
|
|
String word1 = encodeQ(prefix, part1, usage, usedCharacters,
|
|
charset, bytes1);
|
|
|
|
String part2 = text.substring(text.length() / 2);
|
|
byte[] bytes2 = encode(part2, charset);
|
|
String word2 = encodeQ(prefix, part2, usage, 0, charset, bytes2);
|
|
|
|
return word1 + " " + word2;
|
|
}
|
|
}
|
|
|
|
private static int qEncodedLength(byte[] bytes, Usage usage) {
|
|
BitSet qChars = usage == Usage.TEXT_TOKEN ? Q_REGULAR_CHARS
|
|
: Q_RESTRICTED_CHARS;
|
|
|
|
int count = 0;
|
|
|
|
for (int idx = 0; idx < bytes.length; idx++) {
|
|
int v = bytes[idx] & 0xff;
|
|
if (v == 32) {
|
|
count++;
|
|
} else if (!qChars.get(v)) {
|
|
count += 3;
|
|
} else {
|
|
count++;
|
|
}
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
private static byte[] encode(String text, Charset charset) {
|
|
ByteBuffer buffer = charset.encode(text);
|
|
byte[] bytes = new byte[buffer.limit()];
|
|
buffer.get(bytes);
|
|
return bytes;
|
|
}
|
|
|
|
private static Charset determineCharset(String text) {
|
|
// it is an important property of iso-8859-1 that it directly maps
|
|
// unicode code points 0000 to 00ff to byte values 00 to ff.
|
|
boolean ascii = true;
|
|
final int len = text.length();
|
|
for (int index = 0; index < len; index++) {
|
|
char ch = text.charAt(index);
|
|
if (ch > 0xff) {
|
|
return CharsetUtil.UTF_8;
|
|
}
|
|
if (ch > 0x7f) {
|
|
ascii = false;
|
|
}
|
|
}
|
|
return ascii ? CharsetUtil.US_ASCII : CharsetUtil.ISO_8859_1;
|
|
}
|
|
|
|
private static Encoding determineEncoding(byte[] bytes, Usage usage) {
|
|
if (bytes.length == 0)
|
|
return Encoding.Q;
|
|
|
|
BitSet qChars = usage == Usage.TEXT_TOKEN ? Q_REGULAR_CHARS
|
|
: Q_RESTRICTED_CHARS;
|
|
|
|
int qEncoded = 0;
|
|
for (int i = 0; i < bytes.length; i++) {
|
|
int v = bytes[i] & 0xff;
|
|
if (v != 32 && !qChars.get(v)) {
|
|
qEncoded++;
|
|
}
|
|
}
|
|
|
|
int percentage = qEncoded * 100 / bytes.length;
|
|
return percentage > 30 ? Encoding.B : Encoding.Q;
|
|
}
|
|
|
|
private static char hexDigit(int i) {
|
|
return i < 10 ? (char) (i + '0') : (char) (i - 10 + 'A');
|
|
}
|
|
}
|