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