/*
 * The Apache Software License, Version 1.1
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 * reserved.
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 * modification, are permitted provided that the following conditions
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 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 4. The names "Xerces" and "Apache Software Foundation" must
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 * 5. Products derived from this software may not be called "Apache",
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package basics.encoding;
/**
 * 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.
 * @author Jeffrey Rodriguez
 * @author Sandy Gao
 * @version $Id: Base64.java,v 1.8 2003/05/08 20:11:55 elena Exp $
 */
@SuppressWarnings("unused")
public final class Base64
{
static private final int     BASELENGTH           = 255;
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(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;
   int numberLines = (numberQuartet - 1) / 19 + 1;
   char encodedData[] = null;
   encodedData = new char [numberQuartet * 4 + numberLines];
   byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
   int encodedIndex = 0;
   int dataIndex = 0;
   int i = 0;
   if(fDebug)
   {
      System.out.println("number of triplets = " + numberTriplets);
   }
   for(int line = 0; line < numberLines - 1; line++)
   {
      for(int quartet = 0; quartet < 19; quartet++)
      {
         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];
         i++;
      }
      encodedData[encodedIndex++] = 0xa;
   }
   for(; 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;
      }
   encodedData[encodedIndex] = 0xa;
   return new String(encodedData);
}

/**
 * Decodes Base64 data into octects
 * @param binaryData Byte array 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, marker0 = 0, marker1 = 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;
}
}