/*
* EncFS Java Library
* Copyright (C) 2011 Mark R. Pariente
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
/*
* Adapted from the public domain implementation by Robert Harder at:
* http://iharder.sourceforge.net/current/java/base64/
*/
package org.mrpdaemon.sec.encfs;
import java.io.IOException;
import java.math.BigInteger;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Static class to perform Base64 encoding/decoding
*
*/
public final class EncFSBase64 {
private static final Logger LOG = LoggerFactory.getLogger(EncFSBase64.class);
/* ******** P U B L I C F I E L D S ******** */
/**
* No options specified. Value is zero.
*/
private final static int NO_OPTIONS = 0;
/**
* Specify encoding in first bit. Value is one.
*/
private final static int ENCODE = 1;
/**
* Specify decoding in first bit. Value is zero.
*/
private final static int DECODE = 0;
/**
* Specify that data should be gzip-compressed in second bit. Value is two.
*/
private final static int GZIP = 2;
/**
* Specify that gzipped data should <em>not</em> be automatically gunzipped.
*/
private final static int DONT_GUNZIP = 4;
/**
* Do break lines when encoding. Value is 8.
*/
private final static int DO_BREAK_LINES = 8;
/**
* Encode using Base64-like encoding that is URL- and Filename-safe as
* described in Section 4 of RFC3548: <a
* href="http://www.faqs.org/rfcs/rfc3548.html"
* >http://www.faqs.org/rfcs/rfc3548.html</a>. It is important to note that
* data encoded this way is <em>not</em> officially valid Base64, or at the
* very least should not be called Base64 without also specifying that is
* was encoded using the URL- and Filename-safe dialect.
*/
private final static int URL_SAFE = 16;
/**
* Encode using the special "ordered" dialect of Base64 described here: <a
* href="http://www.faqs.org/qa/rfcc-1940.html">http://www.faqs.org/qa/rfcc-
* 1940.html</a>.
*/
private final static int ORDERED = 32;
/* ******** P R I V A T E F I E L D S ******** */
/**
* Maximum line length (76) of Base64 output.
*/
private final static int MAX_LINE_LENGTH = 76;
/**
* The equals sign (=) as a byte.
*/
private final static byte EQUALS_SIGN = (byte) '=';
/**
* The new line character (\n) as a byte.
*/
private final static byte NEW_LINE = (byte) '\n';
/**
* Preferred encoding.
*/
private final static String PREFERRED_ENCODING = "US-ASCII";
private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in
// encoding
private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in
// encoding
/* ******** S T A N D A R D B A S E 6 4 A L P H A B E T ******** */
/**
* The 64 valid Base64 values.
*/
/*
* Host platform me be something funny like EBCDIC, so we hardcode these
* values.
*/
private final static byte[] _STANDARD_ALPHABET = {(byte) 'A', (byte) 'B',
(byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G',
(byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L',
(byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P', (byte) 'Q',
(byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V',
(byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) 'a',
(byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',
(byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k',
(byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p',
(byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u',
(byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z',
(byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4',
(byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
(byte) '+', (byte) '/'};
/**
* Translates a Base64 value to either its 6-bit reconstruction value or a
* negative number indicating some other meaning.
*/
private final static byte[] _STANDARD_DECODABET = {-9, -9, -9, -9, -9, -9,
-9, -9, -9, // Decimal
// 0
// -
// 8
-5, -5, // Whitespace: Tab and Linefeed
-9, -9, // Decimal 11 - 12
-5, // Whitespace: Carriage Return
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
// 26
-9, -9, -9, -9, -9, // Decimal 27 - 31
-5, // Whitespace: Space
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
62, // Plus sign at decimal 43
-9, -9, -9, // Decimal 44 - 46
63, // Slash at decimal 47
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
-9, -9, -9, // Decimal 58 - 60
-1, // Equals sign at decimal 61
-9, -9, -9, // Decimal 62 - 64
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through
// 'N'
14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O'
// through 'Z'
-9, -9, -9, -9, -9, -9, // Decimal 91 - 96
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a'
// through 'm'
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n'
// through 'z'
-9, -9, -9, -9, -9 // Decimal 123 - 127
, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 128 -
// 139
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 140 -
// 152
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 153 -
// 165
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 166 -
// 178
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 179 -
// 191
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 192 -
// 204
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 205 -
// 217
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 218 -
// 230
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 231 -
// 243
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9 // Decimal 244 - 255
};
/* ******** U R L S A F E B A S E 6 4 A L P H A B E T ******** */
/**
* Used in the URL- and Filename-safe dialect described in Section 4 of
* RFC3548: <a
* href="http://www.faqs.org/rfcs/rfc3548.html">http://www.faqs.org
* /rfcs/rfc3548.html</a>. Notice that the last two bytes become "hyphen"
* and "underscore" instead of "plus" and "slash."
*/
private final static byte[] _URL_SAFE_ALPHABET = {(byte) 'A', (byte) 'B',
(byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G',
(byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L',
(byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P', (byte) 'Q',
(byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V',
(byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) 'a',
(byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',
(byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k',
(byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p',
(byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u',
(byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z',
(byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4',
(byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
(byte) '-', (byte) '_'};
/**
* Used in decoding URL- and Filename-safe dialects of Base64.
*/
private final static byte[] _URL_SAFE_DECODABET = {-9, -9, -9, -9, -9, -9,
-9, -9, -9, // Decimal
// 0
// -
// 8
-5, -5, // Whitespace: Tab and Linefeed
-9, -9, // Decimal 11 - 12
-5, // Whitespace: Carriage Return
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
// 26
-9, -9, -9, -9, -9, // Decimal 27 - 31
-5, // Whitespace: Space
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
-9, // Plus sign at decimal 43
-9, // Decimal 44
62, // Minus sign at decimal 45
-9, // Decimal 46
-9, // Slash at decimal 47
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
-9, -9, -9, // Decimal 58 - 60
-1, // Equals sign at decimal 61
-9, -9, -9, // Decimal 62 - 64
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through
// 'N'
14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O'
// through 'Z'
-9, -9, -9, -9, // Decimal 91 - 94
63, // Underscore at decimal 95
-9, // Decimal 96
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a'
// through 'm'
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n'
// through 'z'
-9, -9, -9, -9, -9 // Decimal 123 - 127
, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 128 -
// 139
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 140 -
// 152
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 153 -
// 165
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 166 -
// 178
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 179 -
// 191
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 192 -
// 204
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 205 -
// 217
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 218 -
// 230
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 231 -
// 243
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9 // Decimal 244 - 255
};
/* ******** O R D E R E D B A S E 6 4 A L P H A B E T ******** */
/**
* I don't get the point of this technique, but someone requested it, and it
* is described here: <a
* href="http://www.faqs.org/qa/rfcc-1940.html">http://
* www.faqs.org/qa/rfcc-1940.html</a>.
*/
private final static byte[] _ORDERED_ALPHABET = {(byte) '-', (byte) '0',
(byte) '1', (byte) '2', (byte) '3', (byte) '4', (byte) '5',
(byte) '6', (byte) '7', (byte) '8', (byte) '9', (byte) 'A',
(byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F',
(byte) 'G', (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K',
(byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P',
(byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U',
(byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z',
(byte) '_', (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd',
(byte) 'e', (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i',
(byte) 'j', (byte) 'k', (byte) 'l', (byte) 'm', (byte) 'n',
(byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's',
(byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x',
(byte) 'y', (byte) 'z'};
/**
* Used in decoding the "ordered" dialect of Base64.
*/
private final static byte[] _ORDERED_DECODABET = {-9, -9, -9, -9, -9, -9,
-9, -9, -9, // Decimal
// 0
// -
// 8
-5, -5, // Whitespace: Tab and Linefeed
-9, -9, // Decimal 11 - 12
-5, // Whitespace: Carriage Return
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
// 26
-9, -9, -9, -9, -9, // Decimal 27 - 31
-5, // Whitespace: Space
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
-9, // Plus sign at decimal 43
-9, // Decimal 44
0, // Minus sign at decimal 45
-9, // Decimal 46
-9, // Slash at decimal 47
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, // Numbers zero through nine
-9, -9, -9, // Decimal 58 - 60
-1, // Equals sign at decimal 61
-9, -9, -9, // Decimal 62 - 64
11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, // Letters 'A'
// through 'M'
24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, // Letters 'N'
// through 'Z'
-9, -9, -9, -9, // Decimal 91 - 94
37, // Underscore at decimal 95
-9, // Decimal 96
38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, // Letters 'a'
// through 'm'
51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, // Letters 'n'
// through 'z'
-9, -9, -9, -9, -9 // Decimal 123 - 127
, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 128
// - 139
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 140 -
// 152
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 153 -
// 165
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 166 -
// 178
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 179 -
// 191
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 192 -
// 204
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 205 -
// 217
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 218 -
// 230
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 231 -
// 243
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9 // Decimal 244 - 255
};
/**
* Used in decoding the "ENCFS" dialect of Base64.
*/
private final static byte[] _ENCFS_DECODABET = {-9, -9, -9, -9, -9, -9,
-9, -9, -9, // Decimal
// 0
// -
// 8
-5, -5, // Whitespace: Tab and Linefeed
-9, -9, // Decimal 11 - 12
-5, // Whitespace: Carriage Return
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
// 26
-9, -9, -9, -9, -9, // Decimal 27 - 31
-5, // Whitespace: Space
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
-9, // Plus sign at decimal 43
0, // Comma at decimal 44
1, // Minus sign at decimal 45
-9, // Decimal 46
-9, // Slash at decimal 47
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, // Numbers zero through nine
-9, -9, -9, // Decimal 58 - 60
-1, // Equals sign at decimal 61
-9, -9, -9, // Decimal 62 - 64
12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // Letters 'A'
// through 'M'
25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, // Letters 'N'
// through 'Z'
-9, -9, -9, -9, -9, -9, // Decimal 91 - 96
38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, // Letters 'a'
// through 'm'
51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, // Letters 'n'
// through 'z'
-9, -9, -9, -9, -9 // Decimal 123 - 127
, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 128
// - 139
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 140 -
// 152
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 153 -
// 165
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 166 -
// 178
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 179 -
// 191
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 192 -
// 204
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 205 -
// 217
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 218 -
// 230
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 231 -
// 243
-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9 // Decimal 244 - 255
};
/* ******** D E T E R M I N E W H I C H A L H A B E T ******** */
/**
* Returns one of the _SOMETHING_ALPHABET byte arrays depending on the
* options specified. It's possible, though silly, to specify ORDERED
* <b>and</b> URLSAFE in which case one of them will be picked, though there
* is no guarantee as to which one will be picked.
*/
private static byte[] getAlphabet(int options) {
if ((options&URL_SAFE)==URL_SAFE) {
return _URL_SAFE_ALPHABET;
} else if ((options&ORDERED)==ORDERED) {
return _ORDERED_ALPHABET;
} else {
return _STANDARD_ALPHABET;
}
}
/**
* Returns one of the _SOMETHING_DECODABET byte arrays depending on the
* options specified. It's possible, though silly, to specify ORDERED and
* URL_SAFE in which case one of them will be picked, though there is no
* guarantee as to which one will be picked.
*/
private static byte[] getDecodabet(int options) {
if ((options&URL_SAFE)==URL_SAFE) {
return _URL_SAFE_DECODABET;
} else if ((options&ORDERED)==ORDERED) {
return _ORDERED_DECODABET;
} else {
return _STANDARD_DECODABET;
}
}
/**
* Defeats instantiation.
*/
private EncFSBase64() {
}
/**
* Encodes up to the first three bytes of array <var>threeBytes</var> and
* returns a four-byte array in Base64 notation. The actual number of
* significant bytes in your array is given by <var>numSigBytes</var>. The
* array <var>threeBytes</var> needs only be as big as
* <var>numSigBytes</var>. Code can reuse a byte array by passing a
* four-byte array as <var>b4</var>.
*
* @param b4
* A reusable byte array to reduce array instantiation
* @param threeBytes
* the array to convert
* @param numSigBytes
* the number of significant bytes in your array
* @return four byte array in Base64 notation.
* @since 1.5.1
*/
private static byte[] encode3to4(byte[] b4, byte[] threeBytes,
int numSigBytes, int options) {
encode3to4(threeBytes, 0, numSigBytes, b4, 0, options);
return b4;
}
/**
* <p>
* Encodes up to three bytes of the array <var>source</var> and writes the
* resulting four Base64 bytes to <var>destination</var>. The source and
* destination arrays can be manipulated anywhere along their length by
* specifying <var>srcOffset</var> and <var>destOffset</var>. This method
* does not check to make sure your arrays are large enough to accomodate
* <var>srcOffset</var> + 3 for the <var>source</var> array or
* <var>destOffset</var> + 4 for the <var>destination</var> array. The
* actual number of significant bytes in your array is given by
* <var>numSigBytes</var>.
* </p>
* <p>
* This is the lowest level of the encoding methods with all possible
* parameters.
* </p>
*
* @param source
* the array to convert
* @param srcOffset
* the index where conversion begins
* @param numSigBytes
* the number of significant bytes in your array
* @param destination
* the array to hold the conversion
* @param destOffset
* the index where output will be put
* @return the <var>destination</var> array
* @since 1.3
*/
private static byte[] encode3to4(byte[] source, int srcOffset,
int numSigBytes, byte[] destination, int destOffset, int options) {
byte[] alphabet = getAlphabet(options);
// 1 2 3
// 01234567890123456789012345678901 Bit position
// --------000000001111111122222222 Array position from threeBytes
// --------| || || || | Six bit groups to index ALPHABET
// >>18 >>12 >> 6 >> 0 Right shift necessary
// 0x3f 0x3f 0x3f Additional AND
// Create buffer with zero-padding if there are only one or two
// significant bytes passed in the array.
// We have to shift left 24 in order to flush out the 1's that appear
// when Java treats a value as negative that is cast from a byte to an
// int.
int inBuff = (numSigBytes>0 ? ((source[srcOffset]<<24)>>>8) : 0)
|(numSigBytes>1 ? ((source[srcOffset+1]<<24)>>>16) : 0)
|(numSigBytes>2 ? ((source[srcOffset+2]<<24)>>>24) : 0);
switch (numSigBytes) {
case 3:
destination[destOffset] = alphabet[(inBuff>>>18)];
destination[destOffset+1] = alphabet[(inBuff>>>12)&0x3f];
destination[destOffset+2] = alphabet[(inBuff>>>6)&0x3f];
destination[destOffset+3] = alphabet[(inBuff)&0x3f];
return destination;
case 2:
destination[destOffset] = alphabet[(inBuff>>>18)];
destination[destOffset+1] = alphabet[(inBuff>>>12)&0x3f];
destination[destOffset+2] = alphabet[(inBuff>>>6)&0x3f];
destination[destOffset+3] = EQUALS_SIGN;
return destination;
case 1:
destination[destOffset] = alphabet[(inBuff>>>18)];
destination[destOffset+1] = alphabet[(inBuff>>>12)&0x3f];
destination[destOffset+2] = EQUALS_SIGN;
destination[destOffset+3] = EQUALS_SIGN;
return destination;
default:
return destination;
}
}
/**
* Encodes a byte array into Base64 notation. Does not GZip-compress data.
*
* @param source
* The data to convert
* @return The data in Base64-encoded form
* @since 1.4
*/
public static String encodeBytes(byte[] source) {
// Since we're not going to have the GZIP encoding turned on,
// we're not going to have an IOException thrown, so
// we should not force the user to have to catch it.
String encoded = null;
try {
encoded = encodeBytes(source, source.length);
} catch (IOException ex) {
assert false : ex.getMessage();
}
assert encoded!=null;
return encoded;
}
/**
* Encodes a byte array into Base64 notation.
* <p>
* Example options:
* <p/>
*
* <pre>
* GZIP: gzip-compresses object before encoding it.
* DO_BREAK_LINES: break lines at 76 characters
* <i>Note: Technically, this makes your encoding non-compliant.</i>
* </pre>
* <p>
* Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
* <p>
* Example:
* <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
* <p/>
* <p/>
* <p>
* As of v 2.3, if there is an error with the GZIP stream, the method will
* throw an IOException. <b>This is new to v2.3!</b> In earlier versions, it
* just returned a null value, but in retrospect that's a pretty poor way to
* handle it.
* </p>
*
* @param source
* The data to convert
* @param len
* Length of data to convert
* @return The Base64-encoded data as a String
* @see EncFSBase64#GZIP
* @see EncFSBase64#DO_BREAK_LINES
* @since 2.0
*/
private static String encodeBytes(byte[] source, int len)
throws IOException {
byte[] encoded = encodeBytesToBytes(source, 0, len,
EncFSBase64.NO_OPTIONS);
// Return value according to relevant encoding.
try {
return new String(encoded, PREFERRED_ENCODING);
} catch (java.io.UnsupportedEncodingException uue) {
return new String(encoded);
}
}
/**
* Similar to {@link #encodeBytes(byte[], int)} but returns a byte array
* instead of instantiating a String. This is more efficient if you're
* working with I/O streams and have large data sets to encode.
*
* @param source
* The data to convert
* @param off
* Offset in array where conversion should begin
* @param len
* Length of data to convert
* @param options
* Specified options
* @return The Base64-encoded data as a String
* @see EncFSBase64#GZIP
* @see EncFSBase64#DO_BREAK_LINES
* @since 2.3.1
*/
private static byte[] encodeBytesToBytes(byte[] source, int off, int len,
int options) throws IOException {
if (source==null) {
throw new NullPointerException("Cannot serialize a null array.");
}
if (off<0) {
throw new IllegalArgumentException("Cannot have negative offset: "
+off);
}
if (len<0) {
throw new IllegalArgumentException("Cannot have length offset: "
+len);
}
if (off+len>source.length) {
throw new IllegalArgumentException(
String.format(
"Cannot have offset of %d and length of %d with array of length %d",
off, len, source.length));
}
// Compress?
if ((options&GZIP)!=0) {
java.io.ByteArrayOutputStream baos = null;
java.util.zip.GZIPOutputStream gzos = null;
EncFSBase64.OutputStream b64os = null;
try {
// GZip -> Base64 -> ByteArray
baos = new java.io.ByteArrayOutputStream();
b64os = new EncFSBase64.OutputStream(baos, ENCODE|options);
gzos = new java.util.zip.GZIPOutputStream(b64os);
gzos.write(source, off, len);
gzos.close();
} catch (IOException e) {
// Catch it and then throw it immediately so that
// the finally{} block is called for cleanup.
throw e;
} finally {
try {
gzos.close();
} catch (Exception e) {
}
try {
b64os.close();
} catch (Exception e) {
}
try {
baos.close();
} catch (Exception e) {
}
}
return baos.toByteArray();
} // Else, don't compress. Better not to use streams at all then.
else {
boolean breakLines = (options&DO_BREAK_LINES)!=0;
// int len43 = len * 4 / 3;
// byte[] outBuff = new byte[ ( len43 ) // Main 4:3
// + ( (len % 3) > 0 ? 4 : 0 ) // Account for padding
// + (breakLines ? ( len43 / MAX_LINE_LENGTH ) : 0) ]; // New lines
// Try to determine more precisely how big the array needs to be.
// If we get it right, we don't have to do an array copy, and
// we save a bunch of memory.
int encLen = (len/3)*4+(len%3>0 ? 4 : 0); // Bytes needed
// for actual
// encoding
if (breakLines) {
encLen += encLen/MAX_LINE_LENGTH; // Plus extra newline
// characters
}
byte[] outBuff = new byte[encLen];
int d = 0;
int e = 0;
int len2 = len-2;
int lineLength = 0;
for (; d<len2; d += 3, e += 4) {
encode3to4(source, d+off, 3, outBuff, e, options);
lineLength += 4;
if (breakLines&&lineLength>=MAX_LINE_LENGTH) {
outBuff[e+4] = NEW_LINE;
e++;
lineLength = 0;
}
} // en dfor: each piece of array
if (d<len) {
encode3to4(source, d+off, len-d, outBuff, e, options);
e += 4;
}
// Only resize array if we didn't guess it right.
if (e<=outBuff.length-1) {
// If breaking lines and the last byte falls right at
// the line length (76 bytes per line), there will be
// one extra byte, and the array will need to be resized.
// Not too bad of an estimate on array size, I'd say.
byte[] finalOut = new byte[e];
System.arraycopy(outBuff, 0, finalOut, 0, e);
// System.err.println("Having to resize array from " +
// outBuff.length + " to " + e );
return finalOut;
} else {
// System.err.println("No need to resize array.");
return outBuff;
}
}
}
/* ******** D E C O D I N G M E T H O D S ******** */
/**
* Decodes four bytes from array <var>source</var> and writes the resulting
* bytes (up to three of them) to <var>destination</var>. The source and
* destination arrays can be manipulated anywhere along their length by
* specifying <var>srcOffset</var> and <var>destOffset</var>. This method
* does not check to make sure your arrays are large enough to accomodate
* <var>srcOffset</var> + 4 for the <var>source</var> array or
* <var>destOffset</var> + 3 for the <var>destination</var> array. This
* method returns the actual number of bytes that were converted from the
* Base64 encoding.
* <p>
* This is the lowest level of the decoding methods with all possible
* parameters.
* </p>
*
* @param source
* the array to convert
* @param destination
* the array to hold the conversion
* @param destOffset
* the index where output will be put
* @param options
* alphabet type is pulled from this (standard, url-safe,
* ordered)
* @return the number of decoded bytes converted
* <p/>
* <p/>
* room in the array.
* @since 1.3
*/
private static int decode4to3(byte[] source, byte[] destination,
int destOffset, int options) {
// Lots of error checking and exception throwing
if (source==null) {
throw new NullPointerException("Source array was null.");
}
if (destination==null) {
throw new NullPointerException("Destination array was null.");
}
if (3>=source.length) {
throw new IllegalArgumentException(
String.format(
"Source array with length %d cannot have offset of %d and still process four bytes.",
source.length, 0));
}
if (destOffset<0||destOffset+2>=destination.length) {
throw new IllegalArgumentException(
String.format(
"Destination array with length %d cannot have offset of %d and still store three bytes.",
destination.length, destOffset));
}
byte[] decodabet = getDecodabet(options);
// Example: Dk==
if (source[2]==EQUALS_SIGN) {
// Two ways to do the same thing. Don't know which way I like best.
// int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6
// )
// | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
int outBuff = ((decodabet[source[0]]&0xFF)<<18)
|((decodabet[source[1]]&0xFF)<<12);
destination[destOffset] = (byte) (outBuff>>>16);
return 1;
} // Example: DkL=
else if (source[3]==EQUALS_SIGN) {
// Two ways to do the same thing. Don't know which way I like best.
// int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6
// )
// | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
// | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
int outBuff = ((decodabet[source[0]]&0xFF)<<18)
|((decodabet[source[1]]&0xFF)<<12)
|((decodabet[source[2]]&0xFF)<<6);
destination[destOffset] = (byte) (outBuff>>>16);
destination[destOffset+1] = (byte) (outBuff>>>8);
return 2;
} // Example: DkLE
else {
// Two ways to do the same thing. Don't know which way I like best.
// int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6
// )
// | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
// | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
// | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
int outBuff = ((decodabet[source[0]]&0xFF)<<18)
|((decodabet[source[1]]&0xFF)<<12)
|((decodabet[source[2]]&0xFF)<<6)
|((decodabet[source[3]]&0xFF));
destination[destOffset] = (byte) (outBuff>>16);
destination[destOffset+1] = (byte) (outBuff>>8);
destination[destOffset+2] = (byte) (outBuff);
return 3;
}
}
/**
* Low-level access to decoding ASCII characters in the form of a byte
* array. <strong>Ignores GUNZIP option, if it's set.</strong> This is not
* generally a recommended method, although it is used internally as part of
* the decoding process. Special case: if len = 0, an empty array is
* returned. Still, if you need more speed and reduced memory footprint (and
* aren't gzipping), consider this method.
*
* @param source
* The Base64 encoded data
* @return decoded data
* @since 2.3.1
*/
public static byte[] decode(byte[] source) throws IOException {
return decode(source, source.length, EncFSBase64.NO_OPTIONS);
}
/**
* Low-level access to decoding ASCII characters in the form of a byte
* array. <strong>Ignores GUNZIP option, if it's set.</strong> This is not
* generally a recommended method, although it is used internally as part of
* the decoding process. Special case: if len = 0, an empty array is
* returned. Still, if you need more speed and reduced memory footprint (and
* aren't gzipping), consider this method.
*
* @param source
* The Base64 encoded data
* @param len
* The length of characters to decode
* @param options
* Can specify options such as alphabet type to use
* @return decoded data
* @since 1.3
*/
private static byte[] decode(byte[] source, int len, int options)
throws IOException {
// Lots of error checking and exception throwing
if (source==null) {
throw new NullPointerException("Cannot decode null source array.");
}
if (len>source.length) {
throw new IllegalArgumentException(
String.format(
"Source array with length %d cannot have offset of %d and process %d bytes.",
source.length, 0, len));
}
if (len==0) {
return new byte[0];
} else if (len<4) {
throw new IllegalArgumentException(
"Base64-encoded string must have at least four characters, but length specified was "
+len);
}
byte[] decodabet = getDecodabet(options);
int len34 = len*3/4; // Estimate on array size
byte[] outBuff = new byte[len34]; // Upper limit on size of output
int outBuffPosn = 0; // Keep track of where we're writing
byte[] b4 = new byte[4]; // Four byte buffer from source, eliminating
// white space
int b4Posn = 0; // Keep track of four byte input buffer
for (int i = 0; i<len; i++) { // Loop through source
// Special value from DECODABET
byte sbiDecode = decodabet[source[i]&0xFF];
// White space, Equals sign, or legit Base64 character
// Note the values such as -5 and -9 in the
// DECODABETs at the top of the file.
if (sbiDecode>=WHITE_SPACE_ENC) {
if (sbiDecode>=EQUALS_SIGN_ENC) {
b4[b4Posn++] = source[i]; // Save non-whitespace
if (b4Posn>3) { // Time to decode?
outBuffPosn += decode4to3(b4, outBuff, outBuffPosn,
options);
b4Posn = 0;
// If that was the equals sign, break out of 'for' loop
if (source[i]==EQUALS_SIGN) {
break;
}
}
}
} else {
// There's a bad input character in the Base64 stream.
throw new IOException(
String.format(
"Bad Base64 input character decimal %d in array position %d",
source[i]&0xFF, i));
}
} // each input character
byte[] out = new byte[outBuffPosn];
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
return out;
}
/**
* Decodes data from Base64 notation, automatically detecting
* gzip-compressed data and decompressing it.
*
* @param s
* the string to decode
* @return the decoded data
* @since 1.4
*/
public static byte[] decode(String s) throws IOException {
return decode(s, NO_OPTIONS);
}
/**
* Decodes data from Base64 notation, automatically detecting
* gzip-compressed data and decompressing it.
*
* @param s
* the string to decode
* @param options
* encode options such as URL_SAFE
* @return the decoded data
* @since 1.4
*/
private static byte[] decode(String s, int options) throws IOException {
if (s==null) {
throw new NullPointerException("Input string was null.");
}
byte[] bytes;
try {
bytes = s.getBytes(PREFERRED_ENCODING);
} catch (java.io.UnsupportedEncodingException uee) {
bytes = s.getBytes();
}
// </change>
// Decode
bytes = decode(bytes, bytes.length, options);
// Check to see if it's gzip-compressed
// GZIP Magic Two-Byte Number: 0x8b1f (35615)
boolean dontGunzip = (options&DONT_GUNZIP)!=0;
if ((bytes!=null)&&(bytes.length>=4)&&(!dontGunzip)) {
int head = (bytes[0]&0xff)|((bytes[1]<<8)&0xff00);
if (java.util.zip.GZIPInputStream.GZIP_MAGIC==head) {
java.io.ByteArrayInputStream bais = null;
java.util.zip.GZIPInputStream gzis = null;
java.io.ByteArrayOutputStream baos = null;
byte[] buffer = new byte[2048];
try {
baos = new java.io.ByteArrayOutputStream();
bais = new java.io.ByteArrayInputStream(bytes);
gzis = new java.util.zip.GZIPInputStream(bais);
int length;
while ((length = gzis.read(buffer))>=0) {
baos.write(buffer, 0, length);
}
// No error? Get new bytes.
bytes = baos.toByteArray();
} catch (IOException e) {
LOG.error("decode()", e);
// Just return originally-decoded bytes
} finally {
try {
baos.close();
} catch (Exception e) {
LOG.warn("decode()", e);
}
try {
gzis.close();
} catch (Exception e) {
LOG.warn("decode()", e);
}
try {
bais.close();
} catch (Exception e) {
LOG.warn("decode()", e);
}
}
}
}
return bytes;
}
/**
* EncFS variant of Base64 encoding
* <p/>
* firstly converts the stream to base 64 by stored as the higher bits of
* the last byte in the low bits of next byte (using only 6 bits per byte)
* <p/>
* Input Bytes: aaAAAAAA bbbbBBBB ccccccCC
* <p/>
* Output Bytes: 00AAAAAA 00BBBBaa 00CCbbbb 00ccccccc
*
* @param src
* Byte array containing input data
* @return Byte array containing encoded data
*/
public static byte[] encodeEncfs(byte[] src) {
int dstPower = 6;
int srcPower = 8;
byte[] result = changeBase2(src, dstPower, srcPower);
base64ToAscii(result);
return result;
}
private static byte[] changeBase2(byte[] src, int dstPower, int srcPower) {
double tmpResultSize = (src.length*(double) srcPower)/dstPower;
int resultSize = (int) Math.ceil(tmpResultSize);
byte[] result = new byte[resultSize];
int dstIdx = 0;
long mask = (1<<dstPower)-1; // 00111111
int workingBits = 0;
BigInteger buffer = BigInteger.valueOf(0);
for (byte aSrc : src) {
int unsignedIntValue = aSrc&0xff;
buffer = buffer.or(BigInteger.valueOf(unsignedIntValue).shiftLeft(
workingBits));
workingBits += srcPower;
while (workingBits>dstPower) {
result[dstIdx++] = buffer.and(BigInteger.valueOf(mask))
.byteValue();
buffer = buffer.shiftRight(dstPower);
workingBits -= dstPower;
}
}
// now, we could have a partial value left in the work buffer..
if (workingBits>0) {
result[dstIdx++] = buffer.and(BigInteger.valueOf(mask)).byteValue();
}
return result;
}
private static final char[] B64_TO_ASCII_TABLE = ",-0123456789".toCharArray();
private static void base64ToAscii(byte[] in) {
int length = in.length;
for (int offset = 0; offset<length; ++offset) {
int ch = in[offset];
if (ch>11) {
if (ch>37) {
ch += 'a'-38;
} else {
ch += 'A'-12;
}
} else {
ch = B64_TO_ASCII_TABLE[ch];
}
in[offset] = (byte) ch;
}
}
/**
* EncFS variant of Base64 decoding
*
* @param source
* Byte array containing input data
* @return Byte array containing decoded data
*/
public static byte[] decodeEncfs(byte[] source) {
byte[] decodedInput = new byte[source.length];
for (int i = 0; i<source.length; i++) {
int arrayIndex = source[i];
if (arrayIndex>=0) {
decodedInput[i] = _ENCFS_DECODABET[source[i]];
} else {
decodedInput[i] = -9;
}
}
int outputLen = (source.length*6)/8;
byte[] output = new byte[outputLen];
int srcIdx = 0;
int dstIdx = 0;
int workBits = 0;
long work = 0;
while (srcIdx<source.length) {
work |= decodedInput[srcIdx++]<<workBits;
workBits += 6;
while (workBits>=8) {
output[dstIdx++] = (byte) (work&0xff);
work >>>= 8;
workBits -= 8;
}
}
return output;
}
/* ******** I N N E R C L A S S I N P U T S T R E A M ******** */
/**
* A {@link Base64.InputStream} will read data from another
* <tt>java.io.InputStream</tt>, given in the constructor, and encode/decode
* to/from Base64 notation on the fly.
*
* @see EncFSBase64
* @since 1.3
*/
static class InputStream extends java.io.FilterInputStream {
private final boolean encode; // Encoding or decoding
private int position; // Current position in the buffer
private final byte[] buffer; // Small buffer holding converted data
private final int bufferLength; // Length of buffer (3 or 4)
private int numSigBytes; // Number of meaningful bytes in the buffer
private int lineLength;
private final boolean breakLines; // Break lines at less than 80
// characters
private final int options; // Record options used to create the stream.
private final byte[] decodabet; // Local copies to avoid extra method
// calls
/**
* Constructs a {@link Base64.InputStream} in DECODE mode.
*
* @param in
* the <tt>java.io.InputStream</tt> from which to read data.
* @since 1.3
*/
public InputStream(java.io.InputStream in) {
this(in, DECODE);
}
/**
* Constructs a {@link Base64.InputStream} in either ENCODE or DECODE
* mode.
* <p/>
* Valid options:
* <p/>
*
* <pre>
* ENCODE or DECODE: Encode or Decode as data is read.
* DO_BREAK_LINES: break lines at 76 characters
* (only meaningful when encoding)</i>
* </pre>
* <p/>
* Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>
*
* @param in
* the <tt>java.io.InputStream</tt> from which to read data.
* @param options
* Specified options
* @see EncFSBase64#ENCODE
* @see EncFSBase64#DECODE
* @see EncFSBase64#DO_BREAK_LINES
* @since 2.0
*/
public InputStream(java.io.InputStream in, int options) {
super(in);
this.options = options; // Record for later
this.breakLines = (options&DO_BREAK_LINES)>0;
this.encode = (options&ENCODE)>0;
this.bufferLength = encode ? 4 : 3;
this.buffer = new byte[bufferLength];
this.position = -1;
this.lineLength = 0;
this.decodabet = getDecodabet(options);
}
/**
* Reads enough of the input stream to convert to/from Base64 and
* returns the next byte.
*
* @return next byte
* @since 1.3
*/
@Override
public int read() throws IOException {
// Do we need to get data?
if (position<0) {
if (encode) {
byte[] b3 = new byte[3];
int numBinaryBytes = 0;
for (int i = 0; i<3; i++) {
int b = in.read();
// If end of stream, b is -1.
if (b>=0) {
b3[i] = (byte) b;
numBinaryBytes++;
} else {
break; // out of for loop
}
}
if (numBinaryBytes>0) {
encode3to4(b3, 0, numBinaryBytes, buffer, 0, options);
position = 0;
numSigBytes = 4;
} else {
return -1; // Must be end of stream
}
} // Else decoding
else {
byte[] b4 = new byte[4];
int i;
for (i = 0; i<4; i++) {
// Read four "meaningful" bytes:
int b;
do {
b = in.read();
} while (b>=0
&&decodabet[b&0x7f]<=WHITE_SPACE_ENC);
if (b<0) {
break; // Reads a -1 if end of stream
}
b4[i] = (byte) b;
}
if (i==4) {
numSigBytes = decode4to3(b4, buffer, 0, options);
position = 0;
} else if (i==0) {
return -1;
} else {
// Must have broken out from above.
throw new IOException("Improperly padded Base64 input.");
} // end
}
}
// Got data?
if (position>=0) {
// End of relevant data?
if ( /* !encode && */position>=numSigBytes) {
return -1;
}
if (encode&&breakLines&&lineLength>=MAX_LINE_LENGTH) {
lineLength = 0;
return '\n';
} else {
lineLength++; // This isn't important when decoding
// but throwing an extra "if" seems
// just as wasteful.
int b = buffer[position++];
if (position>=bufferLength) {
position = -1;
}
return b&0xFF; // This is how you "cast" a byte that's
// intended to be unsigned.
}
} // Else error
else {
throw new IOException("Error in Base64 code reading stream.");
}
}
/**
* Calls {@link #read()} repeatedly until the end of stream is reached
* or <var>len</var> bytes are read. Returns number of bytes read into
* array or -1 if end of stream is encountered.
*
* @param dest
* array to hold values
* @param off
* offset for array
* @param len
* max number of bytes to read into array
* @return bytes read into array or -1 if end of stream is encountered.
* @since 1.3
*/
@Override
public int read(byte[] dest, int off, int len) throws IOException {
int i;
int b;
for (i = 0; i<len; i++) {
b = read();
if (b>=0) {
dest[off+i] = (byte) b;
} else if (i==0) {
return -1;
} else {
break; // Out of 'for' loop
} // Out of 'for' loop
}
return i;
}
}
/* ******** I N N E R C L A S S O U T P U T S T R E A M ******** */
/**
* A {@link Base64.OutputStream} will write data to another
* <tt>java.io.OutputStream</tt>, given in the constructor, and
* encode/decode to/from Base64 notation on the fly.
*
* @see EncFSBase64
* @since 1.3
*/
static class OutputStream extends java.io.FilterOutputStream {
private final boolean encode;
private int position;
private byte[] buffer;
private final int bufferLength;
private int lineLength;
private final boolean breakLines;
private final byte[] b4; // Scratch used in a few places
private boolean suspendEncoding;
private final int options; // Record for later
private final byte[] decodabet; // Local copies to avoid extra method
// calls
/**
* Constructs a {@link Base64.OutputStream} in ENCODE mode.
*
* @param out
* the <tt>java.io.OutputStream</tt> to which data will be
* written.
* @since 1.3
*/
public OutputStream(java.io.OutputStream out) {
this(out, ENCODE);
}
/**
* Constructs a {@link Base64.OutputStream} in either ENCODE or DECODE
* mode.
* <p/>
* Valid options:
* <p/>
*
* <pre>
* ENCODE or DECODE: Encode or Decode as data is read.
* DO_BREAK_LINES: don't break lines at 76 characters
* (only meaningful when encoding)</i>
* </pre>
* <p/>
* Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
*
* @param out
* the <tt>java.io.OutputStream</tt> to which data will be
* written.
* @param options
* Specified options.
* @see EncFSBase64#ENCODE
* @see EncFSBase64#DECODE
* @see EncFSBase64#DO_BREAK_LINES
* @since 1.3
*/
public OutputStream(java.io.OutputStream out, int options) {
super(out);
this.breakLines = (options&DO_BREAK_LINES)!=0;
this.encode = (options&ENCODE)!=0;
this.bufferLength = encode ? 3 : 4;
this.buffer = new byte[bufferLength];
this.position = 0;
this.lineLength = 0;
this.suspendEncoding = false;
this.b4 = new byte[4];
this.options = options;
this.decodabet = getDecodabet(options);
}
/**
* Writes the byte to the output stream after converting to/from Base64
* notation. When encoding, bytes are buffered three at a time before
* the output stream actually gets a write() call. When decoding, bytes
* are buffered four at a time.
*
* @param theByte
* the byte to write
* @since 1.3
*/
@Override
public void write(int theByte) throws IOException {
// Encoding suspended?
if (suspendEncoding) {
this.out.write(theByte);
return;
}
// Encode?
if (encode) {
buffer[position++] = (byte) theByte;
if (position>=bufferLength) { // Enough to encode.
this.out.write(encode3to4(b4, buffer, bufferLength, options));
lineLength += 4;
if (breakLines&&lineLength>=MAX_LINE_LENGTH) {
this.out.write(NEW_LINE);
lineLength = 0;
}
position = 0;
}
} // Else, Decoding
else {
// Meaningful Base64 character?
if (decodabet[theByte&0x7f]>WHITE_SPACE_ENC) {
buffer[position++] = (byte) theByte;
if (position>=bufferLength) { // Enough to output.
int len = EncFSBase64
.decode4to3(buffer, b4, 0, options);
out.write(b4, 0, len);
position = 0;
}
} else if (decodabet[theByte&0x7f]!=WHITE_SPACE_ENC) {
throw new IOException("Invalid character in Base64 data.");
}
}
}
/**
* Calls {@link #write(int)} repeatedly until <var>len</var> bytes are
* written.
*
* @param theBytes
* array from which to read bytes
* @param off
* offset for array
* @param len
* max number of bytes to read into array
* @since 1.3
*/
@Override
public void write(byte[] theBytes, int off, int len) throws IOException {
// Encoding suspended?
if (suspendEncoding) {
this.out.write(theBytes, off, len);
return;
}
for (int i = 0; i<len; i++) {
write(theBytes[off+i]);
}
}
/**
* Method added by PHIL. [Thanks, PHIL. -Rob] This pads the buffer
* without closing the stream.
*/
public void flushBase64() throws IOException {
if (position>0) {
if (encode) {
out.write(encode3to4(b4, buffer, position, options));
position = 0;
} else {
throw new IOException("Base64 input not properly padded.");
}
}
}
/**
* Flushes and closes (I think, in the superclass) the stream.
*
* @since 1.3
*/
@Override
public void close() throws IOException {
// 1. Ensure that pending characters are written
flushBase64();
// 2. Actually close the stream
// Base class both flushes and closes.
super.close();
buffer = null;
out = null;
}
/**
* Suspends encoding of the stream. May be helpful if you need to embed
* a piece of base64-encoded data in a stream.
*
* @since 1.5.1
*/
public void suspendEncoding() throws IOException {
flushBase64();
this.suspendEncoding = true;
}
/**
* Resumes encoding of the stream. May be helpful if you need to embed a
* piece of base64-encoded data in a stream.
*
* @since 1.5.1
*/
public void resumeEncoding() {
this.suspendEncoding = false;
}
}
}