text: package org.codehaus.plexus.util;
  
  /*
   * Copyright The Codehaus Foundation.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /**
   * Provides Base64 encoding and decoding as defined by RFC 2045.
   * <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>
   *
   * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
   * @author Apache Software Foundation
   * @since 1.0-dev
   * @version $Id$
   */
  public class Base64
  {
  
      //
      // Source Id: Base64.java 161350 2005-04-14 20:39:46Z ggregory
      //
  
      /**
       * Chunk size per RFC 2045 section 6.8.
       * <p>
       * The {@value} character limit does not count the trailing CRLF, but counts all other characters, including any
       * equal signs.
       * </p>
       *
       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a>
       */
      static final int CHUNK_SIZE = 76;
  
      /**
       * Chunk separator per RFC 2045 section 2.1.
       *
       * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a>
       */
      static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
  
      /**
       * The base length.
       */
      static final int BASELENGTH = 255;
  
      /**
       * Lookup length.
       */
      static final int LOOKUPLENGTH = 64;
  
      /**
       * Used to calculate the number of bits in a byte.
       */
      static final int EIGHTBIT = 8;
  
      /**
       * Used when encoding something which has fewer than 24 bits.
       */
      static final int SIXTEENBIT = 16;
  
      /**
       * Used to determine how many bits data contains.
       */
      static final int TWENTYFOURBITGROUP = 24;
  
      /**
       * Used to get the number of Quadruples.
       */
      static final int FOURBYTE = 4;
  
      /**
       * Used to test the sign of a byte.
       */
      static final int SIGN = -128;
  
      /**
       * Byte used to pad output.
       */
      static final byte PAD = (byte) '=';
  
      /**
       * Contains the Base64 values <code>0</code> through <code>63</code> accessed by using character encodings as
       * indices.
       * <p>
       * For example, <code>base64Alphabet['+']</code> returns <code>62</code>.
       * </p>
       * <p>
       * The value of undefined encodings is <code>-1</code>.
       * </p>
       */
      private static byte[] base64Alphabet = new byte[BASELENGTH];
  
      /**
       * <p>
       * Contains the Base64 encodings <code>A</code> through <code>Z</code>, followed by <code>a</code> through
       * <code>z</code>, followed by <code>0</code> through <code>9</code>, followed by <code>+</code>, and
       * <code>/</code>.
       * </p>
       * <p>
       * This array is accessed by using character values as indices.
       * </p>
       * <p>
       * For example, <code>lookUpBase64Alphabet[62] </code> returns <code>'+'</code>.
       * </p>
       */
      private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
  
      // Populating the lookup and character arrays
      static
      {
          for ( int i = 0; i < BASELENGTH; i++ )
          {
              base64Alphabet[i] = (byte) -1;
          }
          for ( int i = 'Z'; i >= 'A'; i-- )
          {
              base64Alphabet[i] = (byte) ( i - 'A' );
          }
          for ( int i = 'z'; i >= 'a'; i-- )
          {
              base64Alphabet[i] = (byte) ( i - 'a' + 26 );
          }
          for ( int i = '9'; i >= '0'; i-- )
          {
              base64Alphabet[i] = (byte) ( i - '0' + 52 );
          }
  
          base64Alphabet['+'] = 62;
          base64Alphabet['/'] = 63;
  
          for ( int i = 0; i <= 25; i++ )
          {
              lookUpBase64Alphabet[i] = (byte) ( 'A' + i );
          }
  
          for ( int i = 26, j = 0; i <= 51; i++, j++ )
          {
              lookUpBase64Alphabet[i] = (byte) ( 'a' + j );
          }
  
          for ( int i = 52, j = 0; i <= 61; i++, j++ )
          {
              lookUpBase64Alphabet[i] = (byte) ( '0' + j );
          }
  
          lookUpBase64Alphabet[62] = (byte) '+';
          lookUpBase64Alphabet[63] = (byte) '/';
      }
  
      /**
       * Returns whether or not the <code>octect</code> is in the base 64 alphabet.
       *
       * @param octect The value to test
       * @return <code>true</code> if the value is defined in the the base 64 alphabet, <code>false</code> otherwise.
       */
      private static boolean isBase64( byte octect )
      {
          if ( octect == PAD )
          {
              return true;
          }
          else if ( octect < 0 || base64Alphabet[octect] == -1 )
          {
              return false;
          }
          else
          {
              return true;
          }
      }
  
      /**
       * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
       *
       * @param arrayOctect 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;
       *         false, otherwise
       */
      public static boolean isArrayByteBase64( byte[] arrayOctect )
      {
  
          arrayOctect = discardWhitespace( arrayOctect );
  
          int length = arrayOctect.length;
          if ( length == 0 )
          {
              // shouldn't a 0 length array be valid base64 data?
              // return false;
              return true;
          }
          for ( byte anArrayOctect : arrayOctect )
          {
              if ( !isBase64( anArrayOctect ) )
              {
                  return false;
              }
          }
          return true;
      }
  
      /**
       * Encodes binary data using the base64 algorithm but does not chunk the output.
       *
       * @param binaryData binary data to encode
       * @return Base64 characters
       */
      public static byte[] encodeBase64( byte[] binaryData )
      {
          return encodeBase64( binaryData, false );
      }
  
      /**
       * 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( byte[] binaryData )
      {
          return encodeBase64( binaryData, true );
      }
  
      /**
       * Decodes a byte[] containing containing characters in the Base64 alphabet.
       *
       * @param pArray A byte array containing Base64 character data
       * @return a byte array containing binary data
       */
      public byte[] decode( byte[] pArray )
      {
          return decodeBase64( pArray );
      }
  
      /**
       * 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.
       */
      public static byte[] encodeBase64( byte[] binaryData, boolean isChunked )
      {
          int lengthDataBits = binaryData.length * EIGHTBIT;
          int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
          int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
          byte encodedData[] = null;
          int encodedDataLength = 0;
          int nbrChunks = 0;
  
          if ( fewerThan24bits != 0 )
          {
              // data not divisible by 24 bit
              encodedDataLength = ( numberTriplets + 1 ) * 4;
          }
          else
          {
              // 16 or 8 bit
              encodedDataLength = numberTriplets * 4;
          }
  
          // If the output is to be "chunked" into 76 character sections,
          // for compliance with RFC 2045 MIME, then it is important to
          // allow for extra length to account for the separator(s)
          if ( isChunked )
          {
  
              nbrChunks = ( CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil( (float) encodedDataLength / CHUNK_SIZE ) );
              encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
          }
  
          encodedData = new byte[encodedDataLength];
  
          byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
  
          int encodedIndex = 0;
          int dataIndex = 0;
          int i = 0;
          int nextSeparatorIndex = CHUNK_SIZE;
          int chunksSoFar = 0;
  
          // log.debug("number of triplets = " + numberTriplets);
          for ( i = 0; i < numberTriplets; i++ )
          {
              dataIndex = i * 3;
              b1 = binaryData[dataIndex];
              b2 = binaryData[dataIndex + 1];
              b3 = binaryData[dataIndex + 2];
  
              // log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);
  
              l = (byte) ( b2 & 0x0f );
              k = (byte) ( b1 & 0x03 );
  
              byte val1 = ( ( b1 & SIGN ) == 0 ) ? (byte) ( b1 >> 2 ) : (byte) ( ( b1 ) >> 2 ^ 0xc0 );
              byte val2 = ( ( b2 & SIGN ) == 0 ) ? (byte) ( b2 >> 4 ) : (byte) ( ( b2 ) >> 4 ^ 0xf0 );
              byte val3 = ( ( b3 & SIGN ) == 0 ) ? (byte) ( b3 >> 6 ) : (byte) ( ( b3 ) >> 6 ^ 0xfc );
  
              encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
              // log.debug( "val2 = " + val2 );
              // log.debug( "k4 = " + (k<<4) );
              // log.debug( "vak = " + (val2 | (k<<4)) );
              encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | ( k << 4 )];
              encodedData[encodedIndex + 2] = lookUpBase64Alphabet[( l << 2 ) | val3];
              encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
  
              encodedIndex += 4;
  
              // If we are chunking, let's put a chunk separator down.
              if ( isChunked )
              {
                  // this assumes that CHUNK_SIZE % 4 == 0
                  if ( encodedIndex == nextSeparatorIndex )
                  {
                      System.arraycopy( CHUNK_SEPARATOR, 0, encodedData, encodedIndex, CHUNK_SEPARATOR.length );
                      chunksSoFar++;
                      nextSeparatorIndex =
                          ( CHUNK_SIZE * ( chunksSoFar + 1 ) ) + ( chunksSoFar * CHUNK_SEPARATOR.length );
                      encodedIndex += CHUNK_SEPARATOR.length;
                  }
              }
          }
  
          // form integral number of 6-bit groups
          dataIndex = i * 3;
  
          if ( fewerThan24bits == EIGHTBIT )
          {
              b1 = binaryData[dataIndex];
              k = (byte) ( b1 & 0x03 );
              // log.debug("b1=" + b1);
              // log.debug("b1<<2 = " + (b1>>2) );
              byte val1 = ( ( b1 & SIGN ) == 0 ) ? (byte) ( b1 >> 2 ) : (byte) ( ( b1 ) >> 2 ^ 0xc0 );
              encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
              encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
              encodedData[encodedIndex + 2] = PAD;
              encodedData[encodedIndex + 3] = PAD;
          }
          else if ( fewerThan24bits == SIXTEENBIT )
          {
  
              b1 = binaryData[dataIndex];
              b2 = binaryData[dataIndex + 1];
              l = (byte) ( b2 & 0x0f );
              k = (byte) ( b1 & 0x03 );
  
              byte val1 = ( ( b1 & SIGN ) == 0 ) ? (byte) ( b1 >> 2 ) : (byte) ( ( b1 ) >> 2 ^ 0xc0 );
              byte val2 = ( ( b2 & SIGN ) == 0 ) ? (byte) ( b2 >> 4 ) : (byte) ( ( b2 ) >> 4 ^ 0xf0 );
  
              encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
              encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | ( k << 4 )];
              encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
              encodedData[encodedIndex + 3] = PAD;
          }
  
          if ( isChunked )
          {
              // we also add a separator to the end of the final chunk.
              if ( chunksSoFar < nbrChunks )
              {
                  System.arraycopy( CHUNK_SEPARATOR, 0, encodedData, encodedDataLength - CHUNK_SEPARATOR.length,
                                    CHUNK_SEPARATOR.length );
              }
          }
  
          return encodedData;
      }
  
      /**
       * Decodes Base64 data into octects
       *
       * @param base64Data Byte array containing Base64 data
       * @return Array containing decoded data.
       */
      public static byte[] decodeBase64( byte[] base64Data )
      {
          // RFC 2045 requires that we discard ALL non-Base64 characters
          base64Data = discardNonBase64( base64Data );
  
          // handle the edge case, so we don't have to worry about it later
          if ( base64Data.length == 0 )
          {
              return new byte[0];
          }
  
          int numberQuadruple = base64Data.length / FOURBYTE;
          byte decodedData[] = null;
          byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
  
          // Throw away anything not in base64Data
  
          int encodedIndex = 0;
          int dataIndex = 0;
          {
              // this sizes the output array properly - rlw
              int lastData = base64Data.length;
              // ignore the '=' padding
              while ( base64Data[lastData - 1] == PAD )
              {
                  if ( --lastData == 0 )
                  {
                      return new byte[0];
                  }
              }
              decodedData = new byte[lastData - numberQuadruple];
          }
  
          for ( int i = 0; i < numberQuadruple; i++ )
          {
              dataIndex = i * 4;
              marker0 = base64Data[dataIndex + 2];
              marker1 = base64Data[dataIndex + 3];
  
              b1 = base64Alphabet[base64Data[dataIndex]];
              b2 = base64Alphabet[base64Data[dataIndex + 1]];
  
              if ( marker0 != PAD && marker1 != PAD )
              {
                  // No PAD e.g 3cQl
                  b3 = base64Alphabet[marker0];
                  b4 = base64Alphabet[marker1];
  
                  decodedData[encodedIndex] = (byte) ( b1 << 2 | b2 >> 4 );
                  decodedData[encodedIndex + 1] = (byte) ( ( ( b2 & 0xf ) << 4 ) | ( ( b3 >> 2 ) & 0xf ) );
                  decodedData[encodedIndex + 2] = (byte) ( b3 << 6 | b4 );
              }
              else if ( marker0 == PAD )
              {
                  // Two PAD e.g. 3c[Pad][Pad]
                  decodedData[encodedIndex] = (byte) ( b1 << 2 | b2 >> 4 );
              }
              else if ( marker1 == PAD )
              {
                  // One PAD e.g. 3cQ[Pad]
                  b3 = base64Alphabet[marker0];
  
                  decodedData[encodedIndex] = (byte) ( b1 << 2 | b2 >> 4 );
                  decodedData[encodedIndex + 1] = (byte) ( ( ( b2 & 0xf ) << 4 ) | ( ( b3 >> 2 ) & 0xf ) );
              }
              encodedIndex += 3;
          }
          return decodedData;
      }
  
      /**
       * Discards any whitespace from a base-64 encoded block.
       *
       * @param data The base-64 encoded data to discard the whitespace from.
       * @return The data, less whitespace (see RFC 2045).
       */
      static byte[] discardWhitespace( byte[] data )
      {
          byte groomedData[] = new byte[data.length];
          int bytesCopied = 0;
  
          for ( byte aData : data )
          {
              switch ( aData )
              {
                  case (byte) ' ':
                  case (byte) '\n':
                  case (byte) '\r':
                  case (byte) '\t':
                      break;
                  default:
                      groomedData[bytesCopied++] = aData;
              }
          }
  
          byte packedData[] = new byte[bytesCopied];
  
          System.arraycopy( groomedData, 0, packedData, 0, bytesCopied );
  
          return packedData;
      }
  
      /**
       * Discards any characters outside of the base64 alphabet, per the requirements on page 25 of RFC 2045 - "Any
       * characters outside of the base64 alphabet are to be ignored in base64 encoded data."
       *
       * @param data The base-64 encoded data to groom
       * @return The data, less non-base64 characters (see RFC 2045).
       */
      static byte[] discardNonBase64( byte[] data )
      {
          byte groomedData[] = new byte[data.length];
          int bytesCopied = 0;
  
          for ( byte aData : data )
          {
              if ( isBase64( aData ) )
              {
                  groomedData[bytesCopied++] = aData;
              }
          }
  
          byte packedData[] = new byte[bytesCopied];
  
          System.arraycopy( groomedData, 0, packedData, 0, bytesCopied );
  
          return packedData;
      }
  
      /**
       * Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
       *
       * @param pArray a byte array containing binary data
       * @return A byte array containing only Base64 character data
       */
      public byte[] encode( byte[] pArray )
      {
          return encodeBase64( pArray, false );
      }
  
  }
  