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   *  This file is part of AndroidIDE.
   *
   *  AndroidIDE is free software: you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation, either version 3 of the License, or
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   *  AndroidIDE is distributed in the hope that it will be useful,
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   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
   */
  
  /*
   * reserved comment block
   * DO NOT REMOVE OR ALTER!
   */
  /*
   * Copyright 1999-2002,2004 The Apache Software 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.
   */
  
  package jaxp.sun.org.apache.xerces.internal.impl.dv.util;
  
  /**
   * This class provides encode/decode for RFC 2045 Base64 as
   * defined by RFC 2045, N. Freed and N. Borenstein.
   * RFC 2045: Multipurpose Internet Mail Extensions (MIME)
   * Part One: Format of Internet Message Bodies. Reference
   * 1996 Available at: http://www.ietf.org/rfc/rfc2045.txt
   * This class is used by XML Schema binary format validation
   *
   * This implementation does not encode/decode streaming
   * data. You need the data that you will encode/decode
   * already on a byte arrray.
   *
   * @xerces.internal
   *
   * @author Jeffrey Rodriguez
   * @author Sandy Gao
   */
  public final class  Base64 {
  
      static private final int  BASELENGTH         = 128;
      static private final int  LOOKUPLENGTH       = 64;
      static private final int  TWENTYFOURBITGROUP = 24;
      static private final int  EIGHTBIT           = 8;
      static private final int  SIXTEENBIT         = 16;
      static private final int  SIXBIT             = 6;
      static private final int  FOURBYTE           = 4;
      static private final int  SIGN               = -128;
      static private final char PAD                = '=';
      static private final boolean fDebug          = false;
      static final private byte [] base64Alphabet        = new byte[BASELENGTH];
      static final private char [] lookUpBase64Alphabet  = new char[LOOKUPLENGTH];
  
      static {
  
          for (int i = 0; i < BASELENGTH; ++i) {
              base64Alphabet[i] = -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] = (char)('A'+i);
  
          for (int i = 26,  j = 0; i<=51; i++, j++)
              lookUpBase64Alphabet[i] = (char)('a'+ j);
  
          for (int i = 52,  j = 0; i<=61; i++, j++)
              lookUpBase64Alphabet[i] = (char)('0' + j);
          lookUpBase64Alphabet[62] = (char)'+';
          lookUpBase64Alphabet[63] = (char)'/';
  
      }
  
      protected static boolean isWhiteSpace(char octect) {
          return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);
      }
  
      protected static boolean isPad(char octect) {
          return (octect == PAD);
      }
  
      protected static boolean isData(char octect) {
          return (octect < BASELENGTH && base64Alphabet[octect] != -1);
      }
  
      protected static boolean isBase64(char octect) {
          return (isWhiteSpace(octect) || isPad(octect) || isData(octect));
      }
  
      /**
       * Encodes hex octects into Base64
       *
       * @param binaryData Array containing binaryData
       * @return Encoded Base64 array
       */
      public static String encode(byte[] binaryData) {
  
          if (binaryData == null)
              return null;
  
          int      lengthDataBits    = binaryData.length*EIGHTBIT;
          if (lengthDataBits == 0) {
              return "";
          }
  
          int      fewerThan24bits   = lengthDataBits%TWENTYFOURBITGROUP;
          int      numberTriplets    = lengthDataBits/TWENTYFOURBITGROUP;
          int      numberQuartet     = fewerThan24bits != 0 ? numberTriplets+1 : numberTriplets;
          char     encodedData[]     = null;
  
          encodedData = new char[numberQuartet*4];
  
          byte k=0, l=0, b1=0,b2=0,b3=0;
  
          int encodedIndex = 0;
          int dataIndex   = 0;
          if (fDebug) {
              System.out.println("number of triplets = " + numberTriplets );
          }
  
          for (int i=0; i<numberTriplets; i++) {
              b1 = binaryData[dataIndex++];
              b2 = binaryData[dataIndex++];
              b3 = binaryData[dataIndex++];
  
              if (fDebug) {
                  System.out.println( "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);
  
              if (fDebug) {
                  System.out.println( "val2 = " + val2 );
                  System.out.println( "k4   = " + (k<<4));
                  System.out.println( "vak  = " + (val2 | (k<<4)));
              }
  
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ val1 ];
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ val2 | ( k<<4 )];
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ (l <<2 ) | val3 ];
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ b3 & 0x3f ];
          }
  
          // form integral number of 6-bit groups
          if (fewerThan24bits == EIGHTBIT) {
              b1 = binaryData[dataIndex];
              k = (byte) ( b1 &0x03 );
              if (fDebug) {
                  System.out.println("b1=" + b1);
                  System.out.println("b1<<2 = " + (b1>>2) );
              }
              byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ val1 ];
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ k<<4 ];
              encodedData[encodedIndex++] = PAD;
              encodedData[encodedIndex++] = 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++] = lookUpBase64Alphabet[ val2 | ( k<<4 )];
              encodedData[encodedIndex++] = lookUpBase64Alphabet[ l<<2 ];
              encodedData[encodedIndex++] = PAD;
          }
  
          return new String(encodedData);
      }
  
      /**
       * Decodes Base64 data into octects
       *
       * @param encoded string containing Base64 data
       * @return Array containind decoded data.
       */
      public static byte[] decode(String encoded) {
  
          if (encoded == null)
              return null;
  
          char[] base64Data = encoded.toCharArray();
          // remove white spaces
          int len = removeWhiteSpace(base64Data);
  
          if (len%FOURBYTE != 0) {
              return null;//should be divisible by four
          }
  
          int      numberQuadruple    = (len/FOURBYTE );
  
          if (numberQuadruple == 0)
              return new byte[0];
  
          byte     decodedData[]      = null;
          byte     b1=0,b2=0,b3=0,b4=0;
          char     d1=0,d2=0,d3=0,d4=0;
  
          int i = 0;
          int encodedIndex = 0;
          int dataIndex    = 0;
          decodedData      = new byte[ (numberQuadruple)*3];
  
          for (; i<numberQuadruple-1; i++) {
  
              if (!isData( (d1 = base64Data[dataIndex++]) )||
                  !isData( (d2 = base64Data[dataIndex++]) )||
                  !isData( (d3 = base64Data[dataIndex++]) )||
                  !isData( (d4 = base64Data[dataIndex++]) ))
                  return null;//if found "no data" just return null
  
              b1 = base64Alphabet[d1];
              b2 = base64Alphabet[d2];
              b3 = base64Alphabet[d3];
              b4 = base64Alphabet[d4];
  
              decodedData[encodedIndex++] = (byte)(  b1 <<2 | b2>>4 ) ;
              decodedData[encodedIndex++] = (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
              decodedData[encodedIndex++] = (byte)( b3<<6 | b4 );
          }
  
          if (!isData( (d1 = base64Data[dataIndex++]) ) ||
              !isData( (d2 = base64Data[dataIndex++]) )) {
              return null;//if found "no data" just return null
          }
  
          b1 = base64Alphabet[d1];
          b2 = base64Alphabet[d2];
  
          d3 = base64Data[dataIndex++];
          d4 = base64Data[dataIndex++];
          if (!isData( (d3 ) ) ||
              !isData( (d4 ) )) {//Check if they are PAD characters
              if (isPad( d3 ) && isPad( d4)) {               //Two PAD e.g. 3c[Pad][Pad]
                  if ((b2 & 0xf) != 0)//last 4 bits should be zero
                      return null;
                  byte[] tmp = new byte[ i*3 + 1 ];
                  System.arraycopy( decodedData, 0, tmp, 0, i*3 );
                  tmp[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 ) ;
                  return tmp;
              } else if (!isPad( d3) && isPad(d4)) {               //One PAD  e.g. 3cQ[Pad]
                  b3 = base64Alphabet[ d3 ];
                  if ((b3 & 0x3 ) != 0)//last 2 bits should be zero
                      return null;
                  byte[] tmp = new byte[ i*3 + 2 ];
                  System.arraycopy( decodedData, 0, tmp, 0, i*3 );
                  tmp[encodedIndex++] = (byte)(  b1 <<2 | b2>>4 );
                  tmp[encodedIndex]   = (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
                  return tmp;
              } else {
                  return null;//an error  like "3c[Pad]r", "3cdX", "3cXd", "3cXX" where X is non data
              }
          } else { //No PAD e.g 3cQl
              b3 = base64Alphabet[ d3 ];
              b4 = base64Alphabet[ d4 ];
              decodedData[encodedIndex++] = (byte)(  b1 <<2 | b2>>4 ) ;
              decodedData[encodedIndex++] = (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
              decodedData[encodedIndex++] = (byte)( b3<<6 | b4 );
  
          }
  
          return decodedData;
      }
  
      /**
       * remove WhiteSpace from MIME containing encoded Base64 data.
       *
       * @param data  the byte array of base64 data (with WS)
       * @return      the new length
       */
      protected static int removeWhiteSpace(char[] data) {
          if (data == null)
              return 0;
  
          // count characters that's not whitespace
          int newSize = 0;
          int len = data.length;
          for (int i = 0; i < len; i++) {
              if (!isWhiteSpace(data[i]))
                  data[newSize++] = data[i];
          }
          return newSize;
      }
  }
  