content: /*
   * 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 com.zzzmode.apkeditor.utils;
  
  import java.math.BigInteger;
  
  /**
   * Provides Base64 encoding and decoding as defined by <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>.
   *
   * <p>
   * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
   * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
   * </p>
   * <p>
   * The class can be parameterized in the following manner with various constructors:
   * </p>
   * <ul>
   * <li>URL-safe mode: Default off.</li>
   * <li>Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of
   * 4 in the encoded data.
   * <li>Line separator: Default is CRLF ("\r\n")</li>
   * </ul>
   * <p>
   * The URL-safe parameter is only applied to encode operations. Decoding seamlessly handles both modes.
   * </p>
   * <p>
   * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only
   * encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252,
   * UTF-8, etc).
   * </p>
   * <p>
   * This class is thread-safe.
   * </p>
   *
   * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
   * @since 1.0
   * @version $Id$
   */
  public class Base64 extends BaseNCodec {
  
      /**
       * BASE32 characters are 6 bits in length.
       * They are formed by taking a block of 3 octets to form a 24-bit string,
       * which is converted into 4 BASE64 characters.
       */
      private static final int BITS_PER_ENCODED_BYTE = 6;
      private static final int BYTES_PER_UNENCODED_BLOCK = 3;
      private static final int BYTES_PER_ENCODED_BLOCK = 4;
  
      /**
       * Chunk separator per RFC 2045 section 2.1.
       *
       * <p>
       * N.B. The next major release may break compatibility and make this field private.
       * </p>
       *
       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
       */
      static final byte[] CHUNK_SEPARATOR = {'\r', '\n'};
  
      /**
       * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"
       * equivalents as specified in Table 1 of RFC 2045.
       *
       * Thanks to "commons" project in ws.apache.org for this code.
       * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
       */
      private static final byte[] STANDARD_ENCODE_TABLE = {
              'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
              'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
              'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
              'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
              '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
      };
  
      /**
       * This is a copy of the STANDARD_ENCODE_TABLE above, but with + and /
       * changed to - and _ to make the encoded Base64 results more URL-SAFE.
       * This table is only used when the Base64's mode is set to URL-SAFE.
       */
      private static final byte[] URL_SAFE_ENCODE_TABLE = {
              'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
              'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
              'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
              'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
              '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
      };
  
      /**
       * This array is a lookup table that translates Unicode characters drawn from the "Base64 Alphabet" (as specified
       * in Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64
       * alphabet but fall within the bounds of the array are translated to -1.
       *
       * Note: '+' and '-' both decode to 62. '/' and '_' both decode to 63. This means decoder seamlessly handles both
       * URL_SAFE and STANDARD base64. (The encoder, on the other hand, needs to know ahead of time what to emit).
       *
       * Thanks to "commons" project in ws.apache.org for this code.
       * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
       */
      private static final byte[] DECODE_TABLE = {
          //   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
              -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f
              -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f
              -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63, // 20-2f + - /
              52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, // 30-3f 0-9
              -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, // 40-4f A-O
              15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, // 50-5f P-Z _
              -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, // 60-6f a-o
              41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51                      // 70-7a p-z
      };
  
      /**
       * Base64 uses 6-bit fields.
       */
      /** Mask used to extract 6 bits, used when encoding */
      private static final int MASK_6BITS = 0x3f;
  
      // The static final fields above are used for the original static byte[] methods on Base64.
      // The private member fields below are used with the new streaming approach, which requires
      // some state be preserved between calls of encode() and decode().
  
      /**
       * Encode table to use: either STANDARD or URL_SAFE. Note: the DECODE_TABLE above remains static because it is able
       * to decode both STANDARD and URL_SAFE streams, but the encodeTable must be a member variable so we can switch
       * between the two modes.
       */
      private final byte[] encodeTable;
  
      // Only one decode table currently; keep for consistency with Base32 code
      private final byte[] decodeTable = DECODE_TABLE;
  
      /**
       * Line separator for encoding. Not used when decoding. Only used if lineLength &gt; 0.
       */
      private final byte[] lineSeparator;
  
      /**
       * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
       * <code>decodeSize = 3 + lineSeparator.length;</code>
       */
      private final int decodeSize;
  
      /**
       * Convenience variable to help us determine when our buffer is going to run out of room and needs resizing.
       * <code>encodeSize = 4 + lineSeparator.length;</code>
       */
      private final int encodeSize;
  
      /**
       * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
       * <p>
       * When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.
       * </p>
       *
       * <p>
       * When decoding all variants are supported.
       * </p>
       */
      public Base64() {
          this(0);
      }
  
      /**
       * Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
       * <p>
       * When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.
       * </p>
       *
       * <p>
       * When decoding all variants are supported.
       * </p>
       *
       * @param urlSafe
       *            if <code>true</code>, URL-safe encoding is used. In most cases this should be set to
       *            <code>false</code>.
       * @since 1.4
       */
      public Base64(final boolean urlSafe) {
          this(MIME_CHUNK_SIZE, CHUNK_SEPARATOR, urlSafe);
      }
  
      /**
       * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
       * <p>
       * When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is
       * STANDARD_ENCODE_TABLE.
       * </p>
       * <p>
       * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
       * </p>
       * <p>
       * When decoding all variants are supported.
       * </p>
       *
       * @param lineLength
       *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
       *            4). If lineLength &lt;= 0, then the output will not be divided into lines (chunks). Ignored when
       *            decoding.
       * @since 1.4
       */
      public Base64(final int lineLength) {
          this(lineLength, CHUNK_SEPARATOR);
      }
  
      /**
       * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
       * <p>
       * When encoding the line length and line separator are given in the constructor, and the encoding table is
       * STANDARD_ENCODE_TABLE.
       * </p>
       * <p>
       * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
       * </p>
       * <p>
       * When decoding all variants are supported.
       * </p>
       *
       * @param lineLength
       *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
       *            4). If lineLength &lt;= 0, then the output will not be divided into lines (chunks). Ignored when
       *            decoding.
       * @param lineSeparator
       *            Each line of encoded data will end with this sequence of bytes.
       * @throws IllegalArgumentException
       *             Thrown when the provided lineSeparator included some base64 characters.
       * @since 1.4
       */
      public Base64(final int lineLength, final byte[] lineSeparator) {
          this(lineLength, lineSeparator, false);
      }
  
      /**
       * Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
       * <p>
       * When encoding the line length and line separator are given in the constructor, and the encoding table is
       * STANDARD_ENCODE_TABLE.
       * </p>
       * <p>
       * Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
       * </p>
       * <p>
       * When decoding all variants are supported.
       * </p>
       *
       * @param lineLength
       *            Each line of encoded data will be at most of the given length (rounded down to nearest multiple of
       *            4). If lineLength &lt;= 0, then the output will not be divided into lines (chunks). Ignored when
       *            decoding.
       * @param lineSeparator
       *            Each line of encoded data will end with this sequence of bytes.
       * @param urlSafe
       *            Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode
       *            operations. Decoding seamlessly handles both modes.
       *            <b>Note: no padding is added when using the URL-safe alphabet.</b>
       * @throws IllegalArgumentException
       *             The provided lineSeparator included some base64 characters. That's not going to work!
       * @since 1.4
       */
      public Base64(final int lineLength, final byte[] lineSeparator, final boolean urlSafe) {
          super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK,
                  lineLength,
                  lineSeparator == null ? 0 : lineSeparator.length);
          // TODO could be simplified if there is no requirement to reject invalid line sep when length <=0
          // @see test case Base64Test.testConstructors()
          if (lineSeparator != null) {
              if (containsAlphabetOrPad(lineSeparator)) {
                  final String sep = StringUtils.newStringUtf8(lineSeparator);
                  throw new IllegalArgumentException("lineSeparator must not contain base64 characters: [" + sep + "]");
              }
              if (lineLength > 0){ // null line-sep forces no chunking rather than throwing IAE
                  this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length;
                  this.lineSeparator = new byte[lineSeparator.length];
                  System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
              } else {
                  this.encodeSize = BYTES_PER_ENCODED_BLOCK;
                  this.lineSeparator = null;
              }
          } else {
              this.encodeSize = BYTES_PER_ENCODED_BLOCK;
              this.lineSeparator = null;
          }
          this.decodeSize = this.encodeSize - 1;
          this.encodeTable = urlSafe ? URL_SAFE_ENCODE_TABLE : STANDARD_ENCODE_TABLE;
      }
  
      /**
       * Returns our current encode mode. True if we're URL-SAFE, false otherwise.
       *
       * @return true if we're in URL-SAFE mode, false otherwise.
       * @since 1.4
       */
      public boolean isUrlSafe() {
          return this.encodeTable == URL_SAFE_ENCODE_TABLE;
      }
  
      /**
       * <p>
       * Encodes all of the provided data, starting at inPos, for inAvail bytes. Must be called at least twice: once with
       * the data to encode, and once with inAvail set to "-1" to alert encoder that EOF has been reached, to flush last
       * remaining bytes (if not multiple of 3).
       * </p>
       * <p><b>Note: no padding is added when encoding using the URL-safe alphabet.</b></p>
       * <p>
       * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
       * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
       * </p>
       *
       * @param in
       *            byte[] array of binary data to base64 encode.
       * @param inPos
       *            Position to start reading data from.
       * @param inAvail
       *            Amount of bytes available from input for encoding.
       * @param context
       *            the context to be used
       */
      @Override
      void encode(final byte[] in, int inPos, final int inAvail, final Context context) {
          if (context.eof) {
              return;
          }
          // inAvail < 0 is how we're informed of EOF in the underlying data we're
          // encoding.
          if (inAvail < 0) {
              context.eof = true;
              if (0 == context.modulus && lineLength == 0) {
                  return; // no leftovers to process and not using chunking
              }
              final byte[] buffer = ensureBufferSize(encodeSize, context);
              final int savedPos = context.pos;
              switch (context.modulus) { // 0-2
                  case 0 : // nothing to do here
                      break;
                  case 1 : // 8 bits = 6 + 2
                      // top 6 bits:
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 2) & MASK_6BITS];
                      // remaining 2:
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 4) & MASK_6BITS];
                      // URL-SAFE skips the padding to further reduce size.
                      if (encodeTable == STANDARD_ENCODE_TABLE) {
                          buffer[context.pos++] = pad;
                          buffer[context.pos++] = pad;
                      }
                      break;
  
                  case 2 : // 16 bits = 6 + 6 + 4
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 10) & MASK_6BITS];
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 4) & MASK_6BITS];
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea << 2) & MASK_6BITS];
                      // URL-SAFE skips the padding to further reduce size.
                      if (encodeTable == STANDARD_ENCODE_TABLE) {
                          buffer[context.pos++] = pad;
                      }
                      break;
                  default:
                      throw new IllegalStateException("Impossible modulus "+context.modulus);
              }
              context.currentLinePos += context.pos - savedPos; // keep track of current line position
              // if currentPos == 0 we are at the start of a line, so don't add CRLF
              if (lineLength > 0 && context.currentLinePos > 0) {
                  System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);
                  context.pos += lineSeparator.length;
              }
          } else {
              for (int i = 0; i < inAvail; i++) {
                  final byte[] buffer = ensureBufferSize(encodeSize, context);
                  context.modulus = (context.modulus+1) % BYTES_PER_UNENCODED_BLOCK;
                  int b = in[inPos++];
                  if (b < 0) {
                      b += 256;
                  }
                  context.ibitWorkArea = (context.ibitWorkArea << 8) + b; //  BITS_PER_BYTE
                  if (0 == context.modulus) { // 3 bytes = 24 bits = 4 * 6 bits to extract
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 18) & MASK_6BITS];
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 12) & MASK_6BITS];
                      buffer[context.pos++] = encodeTable[(context.ibitWorkArea >> 6) & MASK_6BITS];
                      buffer[context.pos++] = encodeTable[context.ibitWorkArea & MASK_6BITS];
                      context.currentLinePos += BYTES_PER_ENCODED_BLOCK;
                      if (lineLength > 0 && lineLength <= context.currentLinePos) {
                          System.arraycopy(lineSeparator, 0, buffer, context.pos, lineSeparator.length);
                          context.pos += lineSeparator.length;
                          context.currentLinePos = 0;
                      }
                  }
              }
          }
      }
  
      /**
       * <p>
       * Decodes all of the provided data, starting at inPos, for inAvail bytes. Should be called at least twice: once
       * with the data to decode, and once with inAvail set to "-1" to alert decoder that EOF has been reached. The "-1"
       * call is not necessary when decoding, but it doesn't hurt, either.
       * </p>
       * <p>
       * Ignores all non-base64 characters. This is how chunked (e.g. 76 character) data is handled, since CR and LF are
       * silently ignored, but has implications for other bytes, too. This method subscribes to the garbage-in,
       * garbage-out philosophy: it will not check the provided data for validity.
       * </p>
       * <p>
       * Thanks to "commons" project in ws.apache.org for the bitwise operations, and general approach.
       * http://svn.apache.org/repos/asf/webservices/commons/trunk/modules/util/
       * </p>
       *
       * @param in
       *            byte[] array of ascii data to base64 decode.
       * @param inPos
       *            Position to start reading data from.
       * @param inAvail
       *            Amount of bytes available from input for encoding.
       * @param context
       *            the context to be used
       */
      @Override
      void decode(final byte[] in, int inPos, final int inAvail, final Context context) {
          if (context.eof) {
              return;
          }
          if (inAvail < 0) {
              context.eof = true;
          }
          for (int i = 0; i < inAvail; i++) {
              final byte[] buffer = ensureBufferSize(decodeSize, context);
              final byte b = in[inPos++];
              if (b == pad) {
                  // We're done.
                  context.eof = true;
                  break;
              } else {
                  if (b >= 0 && b < DECODE_TABLE.length) {
                      final int result = DECODE_TABLE[b];
                      if (result >= 0) {
                          context.modulus = (context.modulus+1) % BYTES_PER_ENCODED_BLOCK;
                          context.ibitWorkArea = (context.ibitWorkArea << BITS_PER_ENCODED_BYTE) + result;
                          if (context.modulus == 0) {
                              buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 16) & MASK_8BITS);
                              buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
                              buffer[context.pos++] = (byte) (context.ibitWorkArea & MASK_8BITS);
                          }
                      }
                  }
              }
          }
  
          // Two forms of EOF as far as base64 decoder is concerned: actual
          // EOF (-1) and first time '=' character is encountered in stream.
          // This approach makes the '=' padding characters completely optional.
          if (context.eof && context.modulus != 0) {
              final byte[] buffer = ensureBufferSize(decodeSize, context);
  
              // We have some spare bits remaining
              // Output all whole multiples of 8 bits and ignore the rest
              switch (context.modulus) {
  //              case 0 : // impossible, as excluded above
                  case 1 : // 6 bits - ignore entirely
                      // TODO not currently tested; perhaps it is impossible?
                      break;
                  case 2 : // 12 bits = 8 + 4
                      context.ibitWorkArea = context.ibitWorkArea >> 4; // dump the extra 4 bits
                      buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
                      break;
                  case 3 : // 18 bits = 8 + 8 + 2
                      context.ibitWorkArea = context.ibitWorkArea >> 2; // dump 2 bits
                      buffer[context.pos++] = (byte) ((context.ibitWorkArea >> 8) & MASK_8BITS);
                      buffer[context.pos++] = (byte) ((context.ibitWorkArea) & MASK_8BITS);
                      break;
                  default:
                      throw new IllegalStateException("Impossible modulus "+context.modulus);
              }
          }
      }
  
      /**
       * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
       * method treats whitespace as valid.
       *
       * @param arrayOctet
       *            byte array to test
       * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
       *         <code>false</code>, otherwise
       * @deprecated 1.5 Use {@link #isBase64(byte[])}, will be removed in 2.0.
       */
      @Deprecated
      public static boolean isArrayByteBase64(final byte[] arrayOctet) {
          return isBase64(arrayOctet);
      }
  
      /**
       * Returns whether or not the <code>octet</code> is in the base 64 alphabet.
       *
       * @param octet
       *            The value to test
       * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
       * @since 1.4
       */
      public static boolean isBase64(final byte octet) {
          return octet == PAD_DEFAULT || (octet >= 0 && octet < DECODE_TABLE.length && DECODE_TABLE[octet] != -1);
      }
  
      /**
       * Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the
       * method treats whitespace as valid.
       *
       * @param base64
       *            String to test
       * @return <code>true</code> if all characters in the String are valid characters in the Base64 alphabet or if
       *         the String is empty; <code>false</code>, otherwise
       *  @since 1.5
       */
      public static boolean isBase64(final String base64) {
          return isBase64(StringUtils.getBytesUtf8(base64));
      }
  
      /**
       * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the
       * method treats whitespace as valid.
       *
       * @param arrayOctet
       *            byte array to test
       * @return <code>true</code> if all bytes are valid characters in the Base64 alphabet or if the byte array is empty;
       *         <code>false</code>, otherwise
       * @since 1.5
       */
      public static boolean isBase64(final byte[] arrayOctet) {
          for (int i = 0; i < arrayOctet.length; i++) {
              if (!isBase64(arrayOctet[i]) && !isWhiteSpace(arrayOctet[i])) {
                  return false;
              }
          }
          return true;
      }
  
      /**
       * Encodes binary data using the base64 algorithm but does not chunk the output.
       *
       * @param binaryData
       *            binary data to encode
       * @return byte[] containing Base64 characters in their UTF-8 representation.
       */
      public static byte[] encodeBase64(final byte[] binaryData) {
          return encodeBase64(binaryData, false);
      }
  
      /**
       * Encodes binary data using the base64 algorithm but does not chunk the output.
       *
       * NOTE:  We changed the behaviour of this method from multi-line chunking (commons-codec-1.4) to
       * single-line non-chunking (commons-codec-1.5).
       *
       * @param binaryData
       *            binary data to encode
       * @return String containing Base64 characters.
       * @since 1.4 (NOTE:  1.4 chunked the output, whereas 1.5 does not).
       */
      public static String encodeBase64String(final byte[] binaryData) {
          return StringUtils.newStringUtf8(encodeBase64(binaryData, false));
      }
  
      /**
       * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
       * url-safe variation emits - and _ instead of + and / characters.
       * <b>Note: no padding is added.</b>
       * @param binaryData
       *            binary data to encode
       * @return byte[] containing Base64 characters in their UTF-8 representation.
       * @since 1.4
       */
      public static byte[] encodeBase64URLSafe(final byte[] binaryData) {
          return encodeBase64(binaryData, false, true);
      }
  
      /**
       * Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The
       * url-safe variation emits - and _ instead of + and / characters.
       * <b>Note: no padding is added.</b>
       * @param binaryData
       *            binary data to encode
       * @return String containing Base64 characters
       * @since 1.4
       */
      public static String encodeBase64URLSafeString(final byte[] binaryData) {
          return StringUtils.newStringUtf8(encodeBase64(binaryData, false, true));
      }
  
      /**
       * Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
       *
       * @param binaryData
       *            binary data to encode
       * @return Base64 characters chunked in 76 character blocks
       */
      public static byte[] encodeBase64Chunked(final byte[] binaryData) {
          return encodeBase64(binaryData, true);
      }
  
      /**
       * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
       *
       * @param binaryData
       *            Array containing binary data to encode.
       * @param isChunked
       *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
       * @return Base64-encoded data.
       * @throws IllegalArgumentException
       *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
       */
      public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked) {
          return encodeBase64(binaryData, isChunked, false);
      }
  
      /**
       * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
       *
       * @param binaryData
       *            Array containing binary data to encode.
       * @param isChunked
       *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
       * @param urlSafe
       *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
       *            <b>Note: no padding is added when encoding using the URL-safe alphabet.</b>
       * @return Base64-encoded data.
       * @throws IllegalArgumentException
       *             Thrown when the input array needs an output array bigger than {@link Integer#MAX_VALUE}
       * @since 1.4
       */
      public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked, final boolean urlSafe) {
          return encodeBase64(binaryData, isChunked, urlSafe, Integer.MAX_VALUE);
      }
  
      /**
       * Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
       *
       * @param binaryData
       *            Array containing binary data to encode.
       * @param isChunked
       *            if <code>true</code> this encoder will chunk the base64 output into 76 character blocks
       * @param urlSafe
       *            if <code>true</code> this encoder will emit - and _ instead of the usual + and / characters.
       *            <b>Note: no padding is added when encoding using the URL-safe alphabet.</b>
       * @param maxResultSize
       *            The maximum result size to accept.
       * @return Base64-encoded data.
       * @throws IllegalArgumentException
       *             Thrown when the input array needs an output array bigger than maxResultSize
       * @since 1.4
       */
      public static byte[] encodeBase64(final byte[] binaryData, final boolean isChunked,
                                        final boolean urlSafe, final int maxResultSize) {
          if (binaryData == null || binaryData.length == 0) {
              return binaryData;
          }
  
          // Create this so can use the super-class method
          // Also ensures that the same roundings are performed by the ctor and the code
          final Base64 b64 = isChunked ? new Base64(urlSafe) : new Base64(0, CHUNK_SEPARATOR, urlSafe);
          final long len = b64.getEncodedLength(binaryData);
          if (len > maxResultSize) {
              throw new IllegalArgumentException("Input array too big, the output array would be bigger (" +
                  len +
                  ") than the specified maximum size of " +
                  maxResultSize);
          }
  
          return b64.encode(binaryData);
      }
  
      /**
       * Decodes a Base64 String into octets.
       * <p>
       * <b>Note:</b> this method seamlessly handles data encoded in URL-safe or normal mode.
       * </p>
       *
       * @param base64String
       *            String containing Base64 data
       * @return Array containing decoded data.
       * @since 1.4
       */
      public static byte[] decodeBase64(final String base64String) {
          return new Base64().decode(base64String);
      }
  
      /**
       * Decodes Base64 data into octets.
       * <p>
       * <b>Note:</b> this method seamlessly handles data encoded in URL-safe or normal mode.
       * </p>
       *
       * @param base64Data
       *            Byte array containing Base64 data
       * @return Array containing decoded data.
       */
      public static byte[] decodeBase64(final byte[] base64Data) {
          return new Base64().decode(base64Data);
      }
  
      // Implementation of the Encoder Interface
  
      // Implementation of integer encoding used for crypto
      /**
       * Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature.
       *
       * @param pArray
       *            a byte array containing base64 character data
       * @return A BigInteger
       * @since 1.4
       */
      public static BigInteger decodeInteger(final byte[] pArray) {
          return new BigInteger(1, decodeBase64(pArray));
      }
  
      /**
       * Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature.
       *
       * @param bigInt
       *            a BigInteger
       * @return A byte array containing base64 character data
       * @throws NullPointerException
       *             if null is passed in
       * @since 1.4
       */
      public static byte[] encodeInteger(final BigInteger bigInt) {
          if (bigInt == null) {
              throw new NullPointerException("encodeInteger called with null parameter");
          }
          return encodeBase64(toIntegerBytes(bigInt), false);
      }
  
      /**
       * Returns a byte-array representation of a <code>BigInteger</code> without sign bit.
       *
       * @param bigInt
       *            <code>BigInteger</code> to be converted
       * @return a byte array representation of the BigInteger parameter
       */
      static byte[] toIntegerBytes(final BigInteger bigInt) {
          int bitlen = bigInt.bitLength();
          // round bitlen
          bitlen = ((bitlen + 7) >> 3) << 3;
          final byte[] bigBytes = bigInt.toByteArray();
  
          if (((bigInt.bitLength() % 8) != 0) && (((bigInt.bitLength() / 8) + 1) == (bitlen / 8))) {
              return bigBytes;
          }
          // set up params for copying everything but sign bit
          int startSrc = 0;
          int len = bigBytes.length;
  
          // if bigInt is exactly byte-aligned, just skip signbit in copy
          if ((bigInt.bitLength() % 8) == 0) {
              startSrc = 1;
              len--;
          }
          final int startDst = bitlen / 8 - len; // to pad w/ nulls as per spec
          final byte[] resizedBytes = new byte[bitlen / 8];
          System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, len);
          return resizedBytes;
      }
  
      /**
       * Returns whether or not the <code>octet</code> is in the Base64 alphabet.
       *
       * @param octet
       *            The value to test
       * @return <code>true</code> if the value is defined in the the Base64 alphabet <code>false</code> otherwise.
       */
      @Override
      protected boolean isInAlphabet(final byte octet) {
          return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;
      }
  
  }