/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.calcite.avatica.util;

//CHECKSTYLE: OFF

import java.nio.charset.StandardCharsets;
import java.util.Locale;

/**
 * <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 <code>options</code> 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(java.lang.String, int, java.lang.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 (<code>int</code>s that you "OR" together).</li>
 *  <li>v1.5.1 - Fixed bug when decompressing and decoding to a
 *   byte[] using <code>decode( String s, boolean gzipCompressed )</code>.
 *   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.
   */
  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.
   */
  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
   * @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
   * @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


  /**
   * 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 java.io.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 java.io.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( java.io.IOException e ) {
      // Catch it and then throw it immediately so that
      // the finally{} block is called for cleanup.
      throw e;
    }   // end catch
    finally {
      try{ oos.close();   } catch( Exception e ){}
      try{ gzos.close();  } catch( Exception e ){}
      try{ b64os.close(); } catch( Exception e ){}
      try{ baos.close();  } catch( Exception e ){}
    }   // end finally

    // Return value according to relevant encoding.
    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(), StandardCharsets.UTF_8 );
    }   // 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 (java.io.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
   *     <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>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 java.io.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 (java.io.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
   *     <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>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 java.io.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, StandardCharsets.UTF_8 );
    }   // 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( java.io.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 java.io.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( Locale.ROOT,
              "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( java.io.IOException e ) {
        // Catch it and then throw it immediately so that
        // the finally{} block is called for cleanup.
        throw e;
      }   // end catch
      finally {
        try{ gzos.close();  } catch( Exception e ){}
        try{ b64os.close(); } catch( Exception e ){}
        try{ baos.close();  } catch( Exception e ){}
      }   // end finally

      return baos.toByteArray();
    }   // end if: compress

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

    }   // end else: don't compress

  }   // 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( Locale.ROOT,
          "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( Locale.ROOT,
          "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
   * @since 2.3.1
   */
  public static byte[] decode( byte[] source )
      throws java.io.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 java.io.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( Locale.ROOT,
          "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 java.io.IOException( String.format( Locale.ROOT,
            "Bad Base64 input character decimal %d in array position %d",
            ((int)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 java.io.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 <code>s</code> is null
   * @since 1.4
   */
  public static byte[] decode( String s, int options ) throws java.io.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( StandardCharsets.UTF_8 );
    }   // 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 = ((int)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( java.io.IOException e ) {
          e.printStackTrace();
          // Just return originally-decoded bytes
        }   // end catch
        finally {
          try{ baos.close(); } catch( Exception e ){}
          try{ gzis.close(); } catch( Exception e ){}
          try{ 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 <code>null</code> 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 java.io.IOException, java.lang.ClassNotFoundException {
    return decodeToObject(encodedObject,NO_OPTIONS,null);
  }


  /**
   * Attempts to decode Base64 data and deserialize a Java
   * Object within. Returns <code>null</code> if there was an error.
   * If <code>loader</code> 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 java.io.IOException, java.lang.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 java.io.IOException, ClassNotFoundException {
            Class c = Class.forName(streamClass.getName(), false, loader);
            if( c == null ){
              return super.resolveClass(streamClass);
            } else {
              return c;   // Class loader knows of this class.
            }   // end else: not null
          }   // end resolveClass
        };  // end ois
      }   // end else: no custom class loader

      obj = ois.readObject();
    }   // end try
    catch( java.io.IOException e ) {
      throw e;    // Catch and throw in order to execute finally{}
    }   // end catch
    catch( java.lang.ClassNotFoundException e ) {
      throw e;    // Catch and throw in order to execute finally{}
    }   // end catch
    finally {
      try{ bais.close(); } catch( Exception e ){}
      try{ 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 java.io.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( java.io.IOException e ) {
      throw e; // Catch and throw to execute finally{} block
    }   // end catch: java.io.IOException
    finally {
      try{ 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 java.io.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( java.io.IOException e ) {
      throw e; // Catch and throw to execute finally{} block
    }   // end catch: java.io.IOException
    finally {
      try{ 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 java.io.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 java.io.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 java.io.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( java.io.IOException e ) {
      throw e; // Catch and release to execute finally{}
    }   // end catch: java.io.IOException
    finally {
      try{ 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 java.io.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 java.io.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( java.io.IOException e ) {
      throw e; // Catch and release to execute finally{}
    }   // end catch: java.io.IOException
    finally {
      try{ bis.close(); } catch( Exception e) {}
    }   // end finally

    return encodedData;
  }   // end encodeFromFile

  /**
   * Reads <code>infile</code> and encodes it to <code>outfile</code>.
   *
   * @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 java.io.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( java.io.IOException e ) {
      throw e; // Catch and release to execute finally{}
    }   // end catch
    finally {
      try { out.close(); }
      catch( Exception ex ){}
    }   // end finally
  }   // end encodeFileToFile


  /**
   * Reads <code>infile</code> and decodes it to <code>outfile</code>.
   *
   * @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 java.io.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( java.io.IOException e ) {
      throw e; // Catch and release to execute finally{}
    }   // end catch
    finally {
      try { 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
   * <code>java.io.InputStream</code>, 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 <code>java.io.InputStream</code> 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)
     * </pre>
     * <p>
     * Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>
     *
     *
     * @param in the <code>java.io.InputStream</code> from which to read data.
     * @param options Specified options
     * @see Base64#ENCODE
     * @see Base64#DECODE
     * @see Base64#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);
    }   // end constructor

    /**
     * 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 java.io.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 java.io.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
        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;
          }   // end if: end

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

      // Else error
      else {
        throw new java.io.IOException( "Error in Base64 code reading stream." );
      }   // end else
    }   // 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 java.io.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
   * <code>java.io.OutputStream</code>, 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 <code>java.io.OutputStream</code> 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)
     * </pre>
     * <p>
     * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
     *
     * @param out the <code>java.io.OutputStream</code> to which data will be written.
     * @param options Specified options.
     * @see Base64#ENCODE
     * @see Base64#DECODE
     * @see Base64#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);
    }   // 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
     */
    @Override
    public void write(int theByte)
        throws java.io.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 java.io.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 java.io.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.
     */
    public void flushBase64() throws java.io.IOException  {
      if( position > 0 ) {
        if( encode ) {
          out.write( encode3to4( b4, buffer, position, options ) );
          position = 0;
        }   // end if: encoding
        else {
          throw new java.io.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 java.io.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 java.io.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

//CHECKSTYLE: ON

// End Base64.java