/*
 * ModeShape (http://www.modeshape.org)
 *
 * Licensed 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.modeshape.schematic;

import java.io.BufferedInputStream;
import java.io.IOException;

/**
 * <p>
 * Encodes and decodes to and from Base64 notation.
 * </p>
 * <p>
 * Homepage: <a href="http://iharder.net/base64">http://iharder.net/base64</a>.
 * </p>
 * <p>
 * Example:
 * </p>
 * <code>String encoded = Base64.encode( myByteArray );</code> <br /> <code>byte[] myByteArray = Base64.decode( encoded );</code>
 * <p>
 * The <tt>options</tt> parameter, which appears in a few places, is used to pass several pieces of information to the encoder. In
 * the "higher level" methods such as encodeBytes( bytes, options ) the options parameter can be used to indicate such things as
 * first gzipping the bytes before encoding them, not inserting linefeeds, and encoding using the URL-safe and Ordered dialects.
 * </p>
 * <p>
 * Note, according to <a href="http://www.faqs.org/rfcs/rfc3548.html">RFC3548</a>, Section 2.1, implementations should not add
 * line feeds unless explicitly told to do so. I've got Base64 set to this behavior now, although earlier versions broke lines by
 * default.
 * </p>
 * <p>
 * The constants defined in Base64 can be OR-ed together to combine options, so you might make a call like this:
 * </p>
 * <code>String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DO_BREAK_LINES );</code>
 * <p>
 * to compress the data before encoding it and then making the output have newline characters.
 * </p>
 * <p>
 * Also...
 * </p>
 * <code>String encoded = Base64.encodeBytes( crazyString.getBytes() );</code>
 * <p>
 * Change Log:
 * </p>
 * <ul>
 * <li>v2.3.7 - Fixed subtle bug when base 64 input stream contained the value 01111111, which is an invalid base 64 character but
 * should not throw an ArrayIndexOutOfBoundsException either. Led to discovery of mishandling (or potential for better handling)
 * of other bad input characters. You should now get an IOException if you try decoding something that has bad characters in it.</li>
 * <li>v2.3.6 - Fixed bug when breaking lines and the final byte of the encoded string ended in the last column; the buffer was
 * not properly shrunk and contained an extra (null) byte that made it into the string.</li>
 * <li>v2.3.5 - Fixed bug in {@link #encodeFromFile} where estimated buffer size was wrong for files of size 31, 34, and 37 bytes.
 * </li>
 * <li>v2.3.4 - Fixed bug when working with gzipped streams whereby flushing the Base64.OutputStream closed the Base64 encoding
 * (by padding with equals signs) too soon. Also added an option to suppress the automatic decoding of gzipped streams. Also added
 * experimental support for specifying a class loader when using the
 * {@link #decodeToObject(String, int, ClassLoader)} method.</li>
 * <li>v2.3.3 - Changed default char encoding to US-ASCII which reduces the internal Java footprint with its CharEncoders and so
 * forth. Fixed some javadocs that were inconsistent. Removed imports and specified things like java.io.IOException explicitly
 * inline.</li>
 * <li>v2.3.2 - Reduced memory footprint! Finally refined the "guessing" of how big the final encoded data will be so that the
 * code doesn't have to create two output arrays: an oversized initial one and then a final, exact-sized one. Big win when using
 * the {@link #encodeBytesToBytes(byte[])} family of methods (and not using the gzip options which uses a different mechanism with
 * streams and stuff).</li>
 * <li>v2.3.1 - Added {@link #encodeBytesToBytes(byte[], int, int, int)} and some similar helper methods to be more efficient with
 * memory by not returning a String but just a byte array.</li>
 * <li>v2.3 - <strong>This is not a drop-in replacement!</strong> This is two years of comments and bug fixes queued up and
 * finally executed. Thanks to everyone who sent me stuff, and I'm sorry I wasn't able to distribute your fixes to everyone else.
 * Much bad coding was cleaned up including throwing exceptions where necessary instead of returning null values or something
 * similar. Here are some changes that may affect you:
 * <ul>
 * <li><em>Does not break lines, by default.</em> This is to keep in compliance with <a
 * href="http://www.faqs.org/rfcs/rfc3548.html">RFC3548</a>.</li>
 * <li><em>Throws exceptions instead of returning null values.</em> Because some operations (especially those that may permit the
 * GZIP option) use IO streams, there is a possiblity of an java.io.IOException being thrown. After some discussion and thought,
 * I've changed the behavior of the methods to throw java.io.IOExceptions rather than return null if ever there's an error. I
 * think this is more appropriate, though it will require some changes to your code. Sorry, it should have been done this way to
 * begin with.</li>
 * <li><em>Removed all references to System.out, System.err, and the like.</em> Shame on me. All I can say is sorry they were ever
 * there.</li>
 * <li><em>Throws NullPointerExceptions and IllegalArgumentExceptions</em> as needed such as when passed arrays are null or
 * offsets are invalid.</li>
 * <li>Cleaned up as much javadoc as I could to avoid any javadoc warnings. This was especially annoying before for people who
 * were thorough in their own projects and then had gobs of javadoc warnings on this file.</li>
 * </ul>
 * <li>v2.2.1 - Fixed bug using URL_SAFE and ORDERED encodings. Fixed bug when using very small files (~&lt; 40 bytes).</li>
 * <li>v2.2 - Added some helper methods for encoding/decoding directly from one file to the next. Also added a main() method to
 * support command line encoding/decoding from one file to the next. Also added these Base64 dialects:
 * <ol>
 * <li>The default is RFC3548 format.</li>
 * <li>Calling Base64.setFormat(Base64.BASE64_FORMAT.URLSAFE_FORMAT) generates URL and file name friendly format as described in
 * Section 4 of RFC3548. http://www.faqs.org/rfcs/rfc3548.html</li>
 * <li>Calling Base64.setFormat(Base64.BASE64_FORMAT.ORDERED_FORMAT) generates URL and file name friendly format that preserves
 * lexical ordering as described in http://www.faqs.org/qa/rfcc-1940.html</li>
 * </ol>
 * Special thanks to Jim Kellerman at <a href="http://www.powerset.com/">http://www.powerset.com/</a> for contributing the new
 * Base64 dialects.</li>
 * <li>v2.1 - Cleaned up javadoc comments and unused variables and methods. Added some convenience methods for reading and writing
 * to and from files.</li>
 * <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems with other encodings (like EBCDIC).</li>
 * <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the encoded data was a single byte.</li>
 * <li>v2.0 - I got rid of methods that used booleans to set options. Now everything is more consolidated and cleaner. The code
 * now detects when data that's being decoded is gzip-compressed and will decompress it automatically. Generally things are
 * cleaner. You'll probably have to change some method calls that you were making to support the new options format (<tt>int</tt>s
 * that you "OR" together).</li>
 * <li>v1.5.1 - Fixed bug when decompressing and decoding to a byte[] using <tt>decode( String s, boolean gzipCompressed )</tt>.
 * Added the ability to "suspend" encoding in the Output Stream so you can turn on and off the encoding if you need to embed
 * base64 data in an otherwise "normal" stream (like an XML file).</li>
 * <li>v1.5 - Output stream pases on flush() command but doesn't do anything itself. This helps when using GZIP streams. Added the
 * ability to GZip-compress objects before encoding them.</li>
 * <li>v1.4 - Added helper methods to read/write files.</li>
 * <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
 * <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream where last buffer being read, if not
 * completely full, was not returned.</li>
 * <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
 * <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
 * </ul>
 * <p>
 * I am placing this code in the Public Domain. Do with it as you will. This software comes with no guarantees or warranties but
 * with plenty of well-wishing instead! Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
 * periodically to check for updates or to contribute improvements.
 * </p>
 * 
 * @author Robert Harder
 * @author rob@iharder.net
 * @version 2.3.7
 */
public class Base64 {

    /* ********  P U B L I C   F I E L D S  ******** */

    /** No options specified. Value is zero. */
    public final static int NO_OPTIONS = 0;

    /** Specify encoding in first bit. Value is one. */
    public final static int ENCODE = 1;

    /** Specify decoding in first bit. Value is zero. */
    public final static int DECODE = 0;

    /** Specify that data should be gzip-compressed in second bit. Value is two. */
    public final static int GZIP = 2;

    /** Specify that gzipped data should <em>not</em> be automatically gunzipped. */
    public final static int DONT_GUNZIP = 4;

    /** Do break lines when encoding. Value is 8. */
    public 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.
     */
    public 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>.
     */
    public 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
    };

    /* ********  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.
     * 
     * @param options the options
     * @return the byte array; never null
     */
    private final 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;
        }
    } // end getAlphabet

    /**
     * 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.
     * 
     * @param options the options
     * @return the byte array; never null
     */
    private final 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;
        }
    } // end getAlphabet

    /** Defeats instantiation. */
    private Base64() {
    }

    /* ********  E N C O D I N G   M E T H O D S  ******** */

    /**
     * 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
     * @param options the options
     * @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;
    } // end encode3to4

    /**
     * <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
     * @param options the options
     * @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;
        } // end switch
    } // end encode3to4

    /**
     * Encodes content of the supplied InputStream into Base64 notation. Does not GZip-compress data.
     * 
     * @param source The data to convert
     * @return the encoded bytes
     */
    public static String encode( java.io.InputStream source ) {
        return encode(source, NO_OPTIONS);
    }

    /**
     * Encodes the content of the supplied InputStream into Base64 notation.
     * <p>
     * Valid options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     * 
     * @param source The data to convert
     * @param options Specified options- the alphabet type is pulled from this (standard, url-safe, ordered)
     * @return the encoded bytes
     * @see Base64#GZIP
     */
    public static String encode( java.io.InputStream source,
                                 int options ) {
        if (source == null) {
            throw new IllegalArgumentException("Source cannot be null");
        }
        java.io.ByteArrayOutputStream baos = new java.io.ByteArrayOutputStream();
        Base64.OutputStream b64os = new Base64.OutputStream(baos, ENCODE | options);
        BufferedInputStream input = new BufferedInputStream(source);
        java.io.OutputStream output = b64os;

        boolean error = false;
        try {
            if ((options & GZIP) == GZIP) {
                output = new java.util.zip.GZIPOutputStream(output);
            }
            int numRead = 0;
            byte[] buffer = new byte[1024];
            while ((numRead = input.read(buffer)) > -1) {
                output.write(buffer, 0, numRead);
            }
            output.close();
        } catch (IOException e) {
            error = true;
            throw new RuntimeException(e); // error using reading from byte array!
        } finally {
            try {
                input.close();
            } catch (IOException e) {
                if (!error) new RuntimeException(e); // error closing input stream
            }
        }

        // Return value according to relevant encoding.
        try {
            return new String(baos.toByteArray(), PREFERRED_ENCODING);
        } catch (java.io.UnsupportedEncodingException uue) {
            return new String(baos.toByteArray());
        }
    }

    /**
     * Performs Base64 encoding on the <code>raw</code> ByteBuffer, writing it to the <code>encoded</code> ByteBuffer. This is an
     * experimental feature. Currently it does not pass along any options (such as {@link #DO_BREAK_LINES} or {@link #GZIP}.
     * 
     * @param raw input buffer
     * @param encoded output buffer
     * @since 2.3
     */
    public static void encode( java.nio.ByteBuffer raw,
                               java.nio.ByteBuffer encoded ) {
        byte[] raw3 = new byte[3];
        byte[] enc4 = new byte[4];

        while (raw.hasRemaining()) {
            int rem = Math.min(3, raw.remaining());
            raw.get(raw3, 0, rem);
            Base64.encode3to4(enc4, raw3, rem, Base64.NO_OPTIONS);
            encoded.put(enc4);
        } // end input remaining
    }

    /**
     * Performs Base64 encoding on the <code>raw</code> ByteBuffer, writing it to the <code>encoded</code> CharBuffer. This is an
     * experimental feature. Currently it does not pass along any options (such as {@link #DO_BREAK_LINES} or {@link #GZIP}.
     * 
     * @param raw input buffer
     * @param encoded output buffer
     * @since 2.3
     */
    public static void encode( java.nio.ByteBuffer raw,
                               java.nio.CharBuffer encoded ) {
        byte[] raw3 = new byte[3];
        byte[] enc4 = new byte[4];

        while (raw.hasRemaining()) {
            int rem = Math.min(3, raw.remaining());
            raw.get(raw3, 0, rem);
            Base64.encode3to4(enc4, raw3, rem, Base64.NO_OPTIONS);
            for (int i = 0; i < 4; i++) {
                encoded.put((char)(enc4[i] & 0xFF));
            }
        } // end input remaining
    }

    /**
     * Serializes an object and returns the Base64-encoded version of that serialized object.
     * <p>
     * As of v 2.3, if the object cannot be serialized or there is another error, the method will throw an java.io.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>
     * The object is not GZip-compressed before being encoded.
     * 
     * @param serializableObject The object to encode
     * @return The Base64-encoded object
     * @throws java.io.IOException if there is an error
     * @throws NullPointerException if serializedObject is null
     * @since 1.4
     */
    public static String encodeObject( java.io.Serializable serializableObject ) throws IOException {
        return encodeObject(serializableObject, NO_OPTIONS);
    } // end encodeObject

    /**
     * Serializes an object and returns the Base64-encoded version of that serialized object.
     * <p>
     * As of v 2.3, if the object cannot be serialized or there is another error, the method will throw an java.io.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>
     * The object is not GZip-compressed before being encoded.
     * <p>
     * Example options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DO_BREAK_LINES: break lines at 76 characters
     * </pre>
     * <p>
     * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
     * <p>
     * Example: <code>encodeObject( myObj, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
     * 
     * @param serializableObject The object to encode
     * @param options Specified options
     * @return The Base64-encoded object
     * @see Base64#GZIP
     * @see Base64#DO_BREAK_LINES
     * @throws java.io.IOException if there is an error
     * @since 2.0
     */
    public static String encodeObject( java.io.Serializable serializableObject,
                                       int options ) throws IOException {

        if (serializableObject == null) {
            throw new NullPointerException("Cannot serialize a null object.");
        } // end if: null

        // Streams
        java.io.ByteArrayOutputStream baos = null;
        java.io.OutputStream b64os = null;
        java.util.zip.GZIPOutputStream gzos = null;
        java.io.ObjectOutputStream oos = null;

        try {
            // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
            baos = new java.io.ByteArrayOutputStream();
            b64os = new Base64.OutputStream(baos, ENCODE | options);
            if ((options & GZIP) != 0) {
                // Gzip
                gzos = new java.util.zip.GZIPOutputStream(b64os);
                oos = new java.io.ObjectOutputStream(gzos);
            } else {
                // Not gzipped
                oos = new java.io.ObjectOutputStream(b64os);
            }
            oos.writeObject(serializableObject);
        } // end try
        catch (IOException e) {
            // Catch it and then throw it immediately so that
            // the finally{} block is called for cleanup.
            throw e;
        } // end catch
        finally {
            try {
                if (oos != null) oos.close();
            } catch (Exception e) {
            }
            try {
                if (gzos != null) gzos.close();
            } catch (Exception e) {
            }
            try {
                if (b64os != null) b64os.close();
            } catch (Exception e) {
            }
            try {
                if (baos != null) baos.close();
            } catch (Exception e) {
            }
        } // end finally

        // Return value according to relevant encoding.
        assert baos != null;
        try {
            return new String(baos.toByteArray(), PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uue) {
            // Fall back to some Java default
            return new String(baos.toByteArray());
        } // end catch

    } // end encode

    /**
     * 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
     * @throws NullPointerException if source array is null
     * @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 java.io.IOException thrown, so
        // we should not force the user to have to catch it.
        String encoded = null;
        try {
            encoded = encodeBytes(source, 0, source.length, NO_OPTIONS);
        } catch (IOException ex) {
            assert false : ex.getMessage();
        } // end catch
        assert encoded != null;
        return encoded;
    } // end encodeBytes

    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Example options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DO_BREAK_LINES: break lines at 76 characters
     *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
     * <p>
     * As of v 2.3, if there is an error with the GZIP stream, the method will throw an java.io.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 options Specified options
     * @return The Base64-encoded data as a String
     * @see Base64#GZIP
     * @see Base64#DO_BREAK_LINES
     * @throws java.io.IOException if there is an error
     * @throws NullPointerException if source array is null
     * @since 2.0
     */
    public static String encodeBytes( byte[] source,
                                      int options ) throws IOException {
        return encodeBytes(source, 0, source.length, options);
    } // end encodeBytes

    /**
     * Encodes a byte array into Base64 notation. Does not GZip-compress data.
     * <p>
     * As of v 2.3, if there is an error, the method will throw an java.io.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 off Offset in array where conversion should begin
     * @param len Length of data to convert
     * @return The Base64-encoded data as a String
     * @throws NullPointerException if source array is null
     * @throws IllegalArgumentException if source array, offset, or length are invalid
     * @since 1.4
     */
    public static String encodeBytes( byte[] source,
                                      int off,
                                      int len ) {
        // Since we're not going to have the GZIP encoding turned on,
        // we're not going to have an java.io.IOException thrown, so
        // we should not force the user to have to catch it.
        String encoded = null;
        try {
            encoded = encodeBytes(source, off, len, NO_OPTIONS);
        } catch (IOException ex) {
            assert false : ex.getMessage();
        } // end catch
        assert encoded != null;
        return encoded;
    } // end encodeBytes

    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Example options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DO_BREAK_LINES: break lines at 76 characters
     *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )</code>
     * <p>
     * As of v 2.3, if there is an error with the GZIP stream, the method will throw an java.io.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 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 Base64#GZIP
     * @see Base64#DO_BREAK_LINES
     * @throws java.io.IOException if there is an error
     * @throws NullPointerException if source array is null
     * @throws IllegalArgumentException if source array, offset, or length are invalid
     * @since 2.0
     */
    public static String encodeBytes( byte[] source,
                                      int off,
                                      int len,
                                      int options ) throws IOException {
        byte[] encoded = encodeBytesToBytes(source, off, len, options);

        // Return value according to relevant encoding.
        try {
            return new String(encoded, PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uue) {
            return new String(encoded);
        } // end catch

    } // end encodeBytes

    /**
     * Similar to {@link #encodeBytes(byte[])} 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
     * @return The Base64-encoded data as a byte[] (of ASCII characters)
     * @throws NullPointerException if source array is null
     * @since 2.3.1
     */
    public static byte[] encodeBytesToBytes( byte[] source ) {
        byte[] encoded = null;
        try {
            encoded = encodeBytesToBytes(source, 0, source.length, Base64.NO_OPTIONS);
        } catch (IOException ex) {
            assert false : "IOExceptions only come from GZipping, which is turned off: " + ex.getMessage();
        }
        return encoded;
    }

    /**
     * Similar to {@link #encodeBytes(byte[], int, int, 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 Base64#GZIP
     * @see Base64#DO_BREAK_LINES
     * @throws java.io.IOException if there is an error
     * @throws NullPointerException if source array is null
     * @throws IllegalArgumentException if source array, offset, or length are invalid
     * @since 2.3.1
     */
    public static byte[] encodeBytesToBytes( byte[] source,
                                             int off,
                                             int len,
                                             int options ) throws IOException {

        if (source == null) {
            throw new NullPointerException("Cannot serialize a null array.");
        } // end if: null

        if (off < 0) {
            throw new IllegalArgumentException("Cannot have negative offset: " + off);
        } // end if: off < 0

        if (len < 0) {
            throw new IllegalArgumentException("Cannot have length offset: " + len);
        } // end if: len < 0

        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));
        } // end if: off < 0

        // Compress?
        if ((options & GZIP) != 0) {
            java.io.ByteArrayOutputStream baos = null;
            java.util.zip.GZIPOutputStream gzos = null;
            Base64.OutputStream b64os = null;

            try {
                // GZip -> Base64 -> ByteArray
                baos = new java.io.ByteArrayOutputStream();
                b64os = new Base64.OutputStream(baos, ENCODE | options);
                gzos = new java.util.zip.GZIPOutputStream(b64os);

                gzos.write(source, off, len);
                gzos.close();
            } // end try
            catch (IOException e) {
                // Catch it and then throw it immediately so that
                // the finally{} block is called for cleanup.
                throw e;
            } // end catch
            finally {
                try {
                    if (gzos != null) gzos.close();
                } catch (Exception e) {
                }
                try {
                    if (b64os != null) b64os.close();
                } catch (Exception e) {
                }
                try {
                    if (baos != null) baos.close();
                } catch (Exception e) {
                }
            } // end finally

            assert baos != null;
            return baos.toByteArray();
        } // end if: compress

        // Else, don't compress. Better not to use streams at all then.
        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;
            } // end if: end of line
        } // en dfor: each piece of array

        if (d < len) {
            encode3to4(source, d + off, len - d, outBuff, e, options);
            e += 4;
        } // end if: some padding needed

        // 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;
        }
        // System.err.println("No need to resize array.");
        return outBuff;

    } // end encodeBytesToBytes

    /* ********  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 srcOffset the index where conversion begins
     * @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
     * @throws NullPointerException if source or destination arrays are null
     * @throws IllegalArgumentException if srcOffset or destOffset are invalid or there is not enough room in the array.
     * @since 1.3
     */
    private static int decode4to3( byte[] source,
                                   int srcOffset,
                                   byte[] destination,
                                   int destOffset,
                                   int options ) {

        // Lots of error checking and exception throwing
        if (source == null) {
            throw new NullPointerException("Source array was null.");
        } // end if
        if (destination == null) {
            throw new NullPointerException("Destination array was null.");
        } // end if
        if (srcOffset < 0 || srcOffset + 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,
                                                       srcOffset));
        } // end if
        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));
        } // end if

        byte[] DECODABET = getDecodabet(options);

        // Example: Dk==
        if (source[srcOffset + 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[srcOffset]] & 0xFF) << 18) | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12);

            destination[destOffset] = (byte)(outBuff >>> 16);
            return 1;
        }

        // Example: DkL=
        else if (source[srcOffset + 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[srcOffset]] & 0xFF) << 18) | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                          | ((DECODABET[source[srcOffset + 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[srcOffset]] & 0xFF) << 18) | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                          | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6) | ((DECODABET[source[srcOffset + 3]] & 0xFF));

            destination[destOffset] = (byte)(outBuff >> 16);
            destination[destOffset + 1] = (byte)(outBuff >> 8);
            destination[destOffset + 2] = (byte)(outBuff);

            return 3;
        }
    } // end decodeToBytes

    /**
     * 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
     * @throws java.io.IOException if there is an error decoding the supplied byte array
     * @since 2.3.1
     */
    public static byte[] decode( byte[] source ) throws IOException {
        byte[] decoded = null;
        // try {
        decoded = decode(source, 0, source.length, Base64.NO_OPTIONS);
        // } catch( java.io.IOException ex ) {
        // assert false : "IOExceptions only come from GZipping, which is turned off: " + ex.getMessage();
        // }
        return decoded;
    }

    /**
     * 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 off The offset of where to begin decoding
     * @param len The length of characters to decode
     * @param options Can specify options such as alphabet type to use
     * @return decoded data
     * @throws java.io.IOException If bogus characters exist in source data
     * @since 1.3
     */
    public static byte[] decode( byte[] source,
                                 int off,
                                 int len,
                                 int options ) throws IOException {

        // Lots of error checking and exception throwing
        if (source == null) {
            throw new NullPointerException("Cannot decode null source array.");
        } // end if
        if (off < 0 || off + len > source.length) {
            throw new IllegalArgumentException(
                                               String.format(
                                                       "Source array with length %d cannot have offset of %d and process %d bytes.",
                                                       source.length,
                                                       off,
                                                       len));
        } // end if

        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);
        } // end if

        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
        int i = 0; // Source array counter
        byte sbiDecode = 0; // Special value from DECODABET

        for (i = off; i < off + len; i++) { // Loop through source

            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, 0, outBuff, outBuffPosn, options);
                        b4Posn = 0;

                        // If that was the equals sign, break out of 'for' loop
                        if (source[i] == EQUALS_SIGN) {
                            break;
                        } // end if: equals sign
                    } // end if: quartet built
                } // end if: equals sign or better
            } // end if: white space, equals sign or better
            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));
            } // end else:
        } // each input character

        byte[] out = new byte[outBuffPosn];
        System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
        return out;
    } // end decode

    /**
     * Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
     * 
     * @param s the string to decode
     * @return the decoded data
     * @throws java.io.IOException If there is a problem
     * @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
     * @throws java.io.IOException if there is an error
     * @throws NullPointerException if <tt>s</tt> is null
     * @since 1.4
     */
    public static byte[] decode( String s,
                                 int options ) throws IOException {

        if (s == null) {
            throw new NullPointerException("Input string was null.");
        } // end if

        byte[] bytes;
        try {
            bytes = s.getBytes(PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uee) {
            bytes = s.getBytes();
        } // end catch
        // </change>

        // Decode
        bytes = decode(bytes, 0, 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];
                int length = 0;

                try {
                    baos = new java.io.ByteArrayOutputStream();
                    bais = new java.io.ByteArrayInputStream(bytes);
                    gzis = new java.util.zip.GZIPInputStream(bais);

                    while ((length = gzis.read(buffer)) >= 0) {
                        baos.write(buffer, 0, length);
                    } // end while: reading input

                    // No error? Get new bytes.
                    bytes = baos.toByteArray();

                } // end try
                catch (IOException e) {
                    e.printStackTrace();
                    // Just return originally-decoded bytes
                } // end catch
                finally {
                    try {
                        if (baos != null) baos.close();
                    } catch (Exception e) {
                    }
                    try {
                        if (gzis != null) gzis.close();
                    } catch (Exception e) {
                    }
                    try {
                        if (bais != null) bais.close();
                    } catch (Exception e) {
                    }
                } // end finally

            } // end if: gzipped
        } // end if: bytes.length >= 2

        return bytes;
    } // end decode

    /**
     * Attempts to decode Base64 data and deserialize a Java Object within. Returns <tt>null</tt> if there was an error.
     * 
     * @param encodedObject The Base64 data to decode
     * @return The decoded and deserialized object
     * @throws NullPointerException if encodedObject is null
     * @throws java.io.IOException if there is a general error
     * @throws ClassNotFoundException if the decoded object is of a class that cannot be found by the JVM
     * @since 1.5
     */
    public static Object decodeToObject( String encodedObject ) throws IOException, ClassNotFoundException {
        return decodeToObject(encodedObject, NO_OPTIONS, null);
    }

    /**
     * Attempts to decode Base64 data and deserialize a Java Object within. Returns <tt>null</tt> if there was an error. If
     * <tt>loader</tt> is not null, it will be the class loader used when deserializing.
     * 
     * @param encodedObject The Base64 data to decode
     * @param options Various parameters related to decoding
     * @param loader Optional class loader to use in deserializing classes.
     * @return The decoded and deserialized object
     * @throws NullPointerException if encodedObject is null
     * @throws java.io.IOException if there is a general error
     * @throws ClassNotFoundException if the decoded object is of a class that cannot be found by the JVM
     * @since 2.3.4
     */
    public static Object decodeToObject( String encodedObject,
                                         int options,
                                         final ClassLoader loader ) throws IOException, ClassNotFoundException {

        // Decode and gunzip if necessary
        byte[] objBytes = decode(encodedObject, options);

        java.io.ByteArrayInputStream bais = null;
        java.io.ObjectInputStream ois = null;
        Object obj = null;

        try {
            bais = new java.io.ByteArrayInputStream(objBytes);

            // If no custom class loader is provided, use Java's builtin OIS.
            if (loader == null) {
                ois = new java.io.ObjectInputStream(bais);
            } // end if: no loader provided

            // Else make a customized object input stream that uses
            // the provided class loader.
            else {
                ois = new java.io.ObjectInputStream(bais) {
                    @Override
                    public Class<?> resolveClass( java.io.ObjectStreamClass streamClass )
                        throws IOException, ClassNotFoundException {
                        Class<?> c = Class.forName(streamClass.getName(), false, loader);
                        if (c == null) {
                            return super.resolveClass(streamClass);
                        }
                        return c; // Class loader knows of this class.
                    } // end resolveClass
                }; // end ois
            } // end else: no custom class loader

            obj = ois.readObject();
        } // end try
        catch (IOException e) {
            throw e; // Catch and throw in order to execute finally{}
        } // end catch
        catch (ClassNotFoundException e) {
            throw e; // Catch and throw in order to execute finally{}
        } // end catch
        finally {
            try {
                if (bais != null) bais.close();
            } catch (Exception e) {
            }
            try {
                if (ois != null) ois.close();
            } catch (Exception e) {
            }
        } // end finally

        return obj;
    } // end decodeObject

    /**
     * Convenience method for encoding data to a file.
     * <p>
     * As of v 2.3, if there is a error, the method will throw an java.io.IOException. <b>This is new to v2.3!</b> In earlier
     * versions, it just returned false, but in retrospect that's a pretty poor way to handle it.
     * </p>
     * 
     * @param dataToEncode byte array of data to encode in base64 form
     * @param filename Filename for saving encoded data
     * @throws java.io.IOException if there is an error
     * @throws NullPointerException if dataToEncode is null
     * @since 2.1
     */
    public static void encodeToFile( byte[] dataToEncode,
                                     String filename ) throws IOException {

        if (dataToEncode == null) {
            throw new NullPointerException("Data to encode was null.");
        } // end iff

        Base64.OutputStream bos = null;
        try {
            bos = new Base64.OutputStream(new java.io.FileOutputStream(filename), Base64.ENCODE);
            bos.write(dataToEncode);
        } // end try
        catch (IOException e) {
            throw e; // Catch and throw to execute finally{} block
        } // end catch: java.io.IOException
        finally {
            try {
                if (bos != null) bos.close();
            } catch (Exception e) {
            }
        } // end finally

    } // end encodeToFile

    /**
     * Convenience method for decoding data to a file.
     * <p>
     * As of v 2.3, if there is a error, the method will throw an java.io.IOException. <b>This is new to v2.3!</b> In earlier
     * versions, it just returned false, but in retrospect that's a pretty poor way to handle it.
     * </p>
     * 
     * @param dataToDecode Base64-encoded data as a string
     * @param filename Filename for saving decoded data
     * @throws java.io.IOException if there is an error
     * @since 2.1
     */
    public static void decodeToFile( String dataToDecode,
                                     String filename ) throws IOException {

        Base64.OutputStream bos = null;
        try {
            bos = new Base64.OutputStream(new java.io.FileOutputStream(filename), Base64.DECODE);
            bos.write(dataToDecode.getBytes(PREFERRED_ENCODING));
        } // end try
        catch (IOException e) {
            throw e; // Catch and throw to execute finally{} block
        } // end catch: java.io.IOException
        finally {
            try {
                if (bos != null) bos.close();
            } catch (Exception e) {
            }
        } // end finally

    } // end decodeToFile

    /**
     * Convenience method for reading a base64-encoded file and decoding it.
     * <p>
     * As of v 2.3, if there is a error, the method will throw an java.io.IOException. <b>This is new to v2.3!</b> In earlier
     * versions, it just returned false, but in retrospect that's a pretty poor way to handle it.
     * </p>
     * 
     * @param filename Filename for reading encoded data
     * @return decoded byte array
     * @throws java.io.IOException if there is an error
     * @since 2.1
     */
    public static byte[] decodeFromFile( String filename ) throws IOException {

        byte[] decodedData = null;
        Base64.InputStream bis = null;
        try {
            // Set up some useful variables
            java.io.File file = new java.io.File(filename);
            byte[] buffer = null;
            int length = 0;
            int numBytes = 0;

            // Check for size of file
            if (file.length() > Integer.MAX_VALUE) {
                throw new IOException("File is too big for this convenience method (" + file.length() + " bytes).");
            } // end if: file too big for int index
            buffer = new byte[(int)file.length()];

            // Open a stream
            bis = new Base64.InputStream(new BufferedInputStream(new java.io.FileInputStream(file)), Base64.DECODE);

            // Read until done
            while ((numBytes = bis.read(buffer, length, 4096)) >= 0) {
                length += numBytes;
            } // end while

            // Save in a variable to return
            decodedData = new byte[length];
            System.arraycopy(buffer, 0, decodedData, 0, length);

        } // end try
        catch (IOException e) {
            throw e; // Catch and release to execute finally{}
        } // end catch: java.io.IOException
        finally {
            try {
                if (bis != null) bis.close();
            } catch (Exception e) {
            }
        } // end finally

        return decodedData;
    } // end decodeFromFile

    /**
     * Convenience method for reading a binary file and base64-encoding it.
     * <p>
     * As of v 2.3, if there is a error, the method will throw an java.io.IOException. <b>This is new to v2.3!</b> In earlier
     * versions, it just returned false, but in retrospect that's a pretty poor way to handle it.
     * </p>
     * 
     * @param filename Filename for reading binary data
     * @return base64-encoded string
     * @throws java.io.IOException if there is an error
     * @since 2.1
     */
    public static String encodeFromFile( String filename ) throws IOException {

        String encodedData = null;
        Base64.InputStream bis = null;
        try {
            // Set up some useful variables
            java.io.File file = new java.io.File(filename);
            byte[] buffer = new byte[Math.max((int)(file.length() * 1.4 + 1), 40)]; // Need max() for math on small files
            // (v2.2.1); Need +1 for a few corner cases
            // (v2.3.5)
            int length = 0;
            int numBytes = 0;

            // Open a stream
            bis = new Base64.InputStream(new BufferedInputStream(new java.io.FileInputStream(file)), Base64.ENCODE);

            // Read until done
            while ((numBytes = bis.read(buffer, length, 4096)) >= 0) {
                length += numBytes;
            } // end while

            // Save in a variable to return
            encodedData = new String(buffer, 0, length, Base64.PREFERRED_ENCODING);

        } // end try
        catch (IOException e) {
            throw e; // Catch and release to execute finally{}
        } // end catch: java.io.IOException
        finally {
            try {
                if (bis != null) bis.close();
            } catch (Exception e) {
            }
        } // end finally

        return encodedData;
    } // end encodeFromFile

    /**
     * Reads <tt>infile</tt> and encodes it to <tt>outfile</tt>.
     * 
     * @param infile Input file
     * @param outfile Output file
     * @throws java.io.IOException if there is an error
     * @since 2.2
     */
    public static void encodeFileToFile( String infile,
                                         String outfile ) throws IOException {

        String encoded = Base64.encodeFromFile(infile);
        java.io.OutputStream out = null;
        try {
            out = new java.io.BufferedOutputStream(new java.io.FileOutputStream(outfile));
            out.write(encoded.getBytes("US-ASCII")); // Strict, 7-bit output.
        } // end try
        catch (IOException e) {
            throw e; // Catch and release to execute finally{}
        } // end catch
        finally {
            try {
                if (out != null) out.close();
            } catch (Exception ex) {
            }
        } // end finally
    } // end encodeFileToFile

    /**
     * Reads <tt>infile</tt> and decodes it to <tt>outfile</tt>.
     * 
     * @param infile Input file
     * @param outfile Output file
     * @throws java.io.IOException if there is an error
     * @since 2.2
     */
    public static void decodeFileToFile( String infile,
                                         String outfile ) throws IOException {

        byte[] decoded = Base64.decodeFromFile(infile);
        java.io.OutputStream out = null;
        try {
            out = new java.io.BufferedOutputStream(new java.io.FileOutputStream(outfile));
            out.write(decoded);
        } // end try
        catch (IOException e) {
            throw e; // Catch and release to execute finally{}
        } // end catch
        finally {
            try {
                if (out != null) out.close();
            } catch (Exception ex) {
            }
        } // end finally
    } // end decodeFileToFile

    /* ********  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 Base64
     * @since 1.3
     */
    public static class InputStream extends java.io.FilterInputStream {

        private boolean encode; // Encoding or decoding
        private int position; // Current position in the buffer
        private byte[] buffer; // Small buffer holding converted data
        private int bufferLength; // Length of buffer (3 or 4)
        private int numSigBytes; // Number of meaningful bytes in the buffer
        private int lineLength;
        private boolean breakLines; // Break lines at less than 80 characters
        private int options; // Record options used to create the stream.
        private 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);
        } // end constructor

        /**
         * Constructs a {@link Base64.InputStream} in either ENCODE or DECODE mode.
         * <p>
         * Valid options:
         * 
         * <pre>
         *   ENCODE or DECODE: Encode or Decode as data is read.
         *   DO_BREAK_LINES: break lines at 76 characters
         *     (only meaningful when encoding)&lt;/i&gt;
         * </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 Base64#ENCODE
         * @see Base64#DECODE
         * @see Base64#DO_BREAK_LINES
         * @since 2.0
         */
        @SuppressWarnings( "synthetic-access" )
        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);
        } // end constructor

        /**
         * Reads enough of the input stream to convert to/from Base64 and returns the next byte.
         * 
         * @return next byte
         * @since 1.3
         */
        @SuppressWarnings( "synthetic-access" )
        @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
                        } // end else: end of stream

                    } // end for: each needed input byte

                    if (numBinaryBytes > 0) {
                        encode3to4(b3, 0, numBinaryBytes, buffer, 0, options);
                        position = 0;
                        numSigBytes = 4;
                    } // end if: got data
                    else {
                        return -1; // Must be end of stream
                    } // end else
                } // end if: encoding

                // Else decoding
                else {
                    byte[] b4 = new byte[4];
                    int i = 0;
                    for (i = 0; i < 4; i++) {
                        // Read four "meaningful" bytes:
                        int b = 0;
                        do {
                            b = in.read();
                        } while (b >= 0 && decodabet[b & 0x7f] <= WHITE_SPACE_ENC);

                        if (b < 0) {
                            break; // Reads a -1 if end of stream
                        } // end if: end of stream

                        b4[i] = (byte)b;
                    } // end for: each needed input byte

                    if (i == 4) {
                        numSigBytes = decode4to3(b4, 0, buffer, 0, options);
                        position = 0;
                    } // end if: got four characters
                    else if (i == 0) {
                        return -1;
                    } // end else if: also padded correctly
                    else {
                        // Must have broken out from above.
                        throw new IOException("Improperly padded Base64 input.");
                    } // end

                } // end else: decode
            } // end else: get data

            // Got data?
            if (position >= 0) {
                // End of relevant data?
                if ( /*!encode &&*/position >= numSigBytes) {
                    return -1;
                } // end if: got data

                if (encode && breakLines && lineLength >= MAX_LINE_LENGTH) {
                    lineLength = 0;
                    return '\n';
                } // end if
                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;
                } // end if: end

                return b & 0xFF; // This is how you "cast" a byte that's
                // intended to be unsigned.
            } // end if: position >= 0

            // Else error
            throw new IOException("Error in Base64 code reading stream.");
        } // end read

        /**
         * 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
            } // end for: each byte read
            return i;
        } // end read

    } // end inner class InputStream

    /* ********  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 Base64
     * @since 1.3
     */
    public static class OutputStream extends java.io.FilterOutputStream {

        private boolean encode;
        private int position;
        private byte[] buffer;
        private int bufferLength;
        private int lineLength;
        private boolean breakLines;
        private byte[] b4; // Scratch used in a few places
        private boolean suspendEncoding;
        private int options; // Record for later
        private 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);
        } // end constructor

        /**
         * Constructs a {@link Base64.OutputStream} in either ENCODE or DECODE mode.
         * <p>
         * Valid options:
         * 
         * <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)&lt;/i&gt;
         * </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 Base64#ENCODE
         * @see Base64#DECODE
         * @see Base64#DO_BREAK_LINES
         * @since 1.3
         */
        @SuppressWarnings( "synthetic-access" )
        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);
        } // end constructor

        /**
         * 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
         */
        @SuppressWarnings( "synthetic-access" )
        @Override
        public void write( int theByte ) throws IOException {
            // Encoding suspended?
            if (suspendEncoding) {
                this.out.write(theByte);
                return;
            } // end if: supsended

            // 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;
                    } // end if: end of line

                    position = 0;
                } // end if: enough to output
            } // end if: encoding

            // 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 = Base64.decode4to3(buffer, 0, b4, 0, options);
                        out.write(b4, 0, len);
                        position = 0;
                    } // end if: enough to output
                } // end if: meaningful base64 character
                else if (decodabet[theByte & 0x7f] != WHITE_SPACE_ENC) {
                    throw new IOException("Invalid character in Base64 data.");
                } // end else: not white space either
            } // end else: decoding
        } // end write

        /**
         * 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;
            } // end if: supsended

            for (int i = 0; i < len; i++) {
                write(theBytes[off + i]);
            } // end for: each byte written

        } // end write

        /**
         * Method added by PHIL. [Thanks, PHIL. -Rob] This pads the buffer without closing the stream.
         * 
         * @throws java.io.IOException if there's an error.
         */
        @SuppressWarnings( "synthetic-access" )
        public void flushBase64() throws IOException {
            if (position > 0) {
                if (encode) {
                    out.write(encode3to4(b4, buffer, position, options));
                    position = 0;
                } // end if: encoding
                else {
                    throw new IOException("Base64 input not properly padded.");
                } // end else: decoding
            } // end if: buffer partially full

        } // end flush

        /**
         * 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;
        } // end close

        /**
         * Suspends encoding of the stream. May be helpful if you need to embed a piece of base64-encoded data in a stream.
         * 
         * @throws java.io.IOException if there's an error flushing
         * @since 1.5.1
         */
        public void suspendEncoding() throws IOException {
            flushBase64();
            this.suspendEncoding = true;
        } // end suspendEncoding

        /**
         * 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;
        } // end resumeEncoding

    } // end inner class OutputStream

} // end class Base64