content: /*
   * Copyright (c) 2010-2018 Nathan Rajlich
   *
   *  Permission is hereby granted, free of charge, to any person
   *  obtaining a copy of this software and associated documentation
   *  files (the "Software"), to deal in the Software without
   *  restriction, including without limitation the rights to use,
   *  copy, modify, merge, publish, distribute, sublicense, and/or sell
   *  copies of the Software, and to permit persons to whom the
   *  Software is furnished to do so, subject to the following
   *  conditions:
   *
   *  The above copyright notice and this permission notice shall be
   *  included in all copies or substantial portions of the Software.
   *
   *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   *  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
   *  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   *  OTHER DEALINGS IN THE SOFTWARE.
   */
  
  package com.alipay.api.java_websocket.util;
  
  /**
   * <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>v2.3.4 - 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 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 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 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 that data should be gzip-compressed in second bit. Value is two.
       */
      public final static int GZIP = 2;
  
      /**
       * 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
  
  
      /* ********  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
  
      /**
       * 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 IllegalArgumentException 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 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
       * @throws java.io.IOException      if there is an error
       * @throws IllegalArgumentException if source array is null, if source array, offset, or length are invalid
       * @see Base64#GZIP
       * @see Base64#DO_BREAK_LINES
       * @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);
          }   // end catch
  
      }   // end encodeBytes
  
      /**
       * 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
       * @throws java.io.IOException      if there is an error
       * @throws IllegalArgumentException if source array is null, if source array, offset, or length are invalid
       * @see Base64#GZIP
       * @see Base64#DO_BREAK_LINES
       * @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 IllegalArgumentException("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 (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 {
                      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 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 IllegalArgumentException if source or destination arrays are null, 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 IllegalArgumentException("Source array was null.");
          }   // end if
          if (destination == null) {
              throw new IllegalArgumentException("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
  
      /**
       * 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
           *     <i>(only meaningful when encoding)</i>
           * </pre>
           * <p>
           * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
           *
           * @param out     the <tt>java.io.OutputStream</tt> to which data will be written.
           * @param options Specified options.
           * @see Base64#ENCODE
           * @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
           */
  
          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
           */
  
          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
           */
  
          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
      }   // end inner class OutputStream
  }   // end class Base64
  