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Base64.javaAPI DocGlassfish v2 API10813Fri May 04 22:33:14 BST 2007org.apache.tomcat.util.buf

Base64

public final class Base64 extends Object
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
author
Jeffrey Rodriguez
version
$Revision: 1.4 $ $Date: 2007/05/05 05:33:13 $

Fields Summary
private static com.sun.org.apache.commons.logging.Log
log
private static final int
BASELENGTH
private static final int
LOOKUPLENGTH
private static final int
TWENTYFOURBITGROUP
private static final int
EIGHTBIT
private static final int
SIXTEENBIT
private static final int
SIXBIT
private static final int
FOURBYTE
private static final byte
PAD
private static byte[]
base64Alphabet
private static byte[]
lookUpBase64Alphabet
static final int[]
base64
Constructors Summary
Methods Summary
public static java.lang.Stringbase64Decode(java.lang.String orig)


           
	char chars[]=orig.toCharArray();
	StringBuffer sb=new StringBuffer();
	int i=0;

	int shift = 0;   // # of excess bits stored in accum
	int acc = 0;
	
	for (i=0; i<chars.length; i++) {
	    int v = base64[ chars[i] & 0xFF ];
	    
	    if ( v >= 64 ) {
		if( chars[i] != '=" )
                    if (log.isDebugEnabled())
		        log.debug("Wrong char in base64: " + chars[i]);
	    } else {
		acc= ( acc << 6 ) | v;
		shift += 6;
		if ( shift >= 8 ) {
		    shift -= 8;
		    sb.append( (char) ((acc >> shift) & 0xff));
		}
	    }
	}
	return sb.toString();
public byte[]decode(byte[] base64Data)
Decodes Base64 data into octects

param
binaryData Byte array containing Base64 data
return
Array containind decoded data.

        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
        // Adjust size

        int encodedIndex = 0;
        int dataIndex    = 0;
        decodedData      = new byte[ numberQuadruple*3 + 1 ];

        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 ) ;
                decodedData[encodedIndex+1] = (byte)((b2 & 0xf)<<4 );
                decodedData[encodedIndex+2] = (byte) 0;
            } 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) );
                decodedData[encodedIndex+2] = (byte)( b3<<6);
            }
            encodedIndex += 3;
        }
        return decodedData;
public static byte[]encode(byte[] binaryData)
Encodes hex octects into Base64

param
binaryData Array containing binaryData
return
Encoded Base64 array

        int      lengthDataBits    = binaryData.length*EIGHTBIT;
        int      fewerThan24bits   = lengthDataBits%TWENTYFOURBITGROUP;
        int      numberTriplets    = lengthDataBits/TWENTYFOURBITGROUP;
        byte     encodedData[]     = null;


        if ( fewerThan24bits != 0 ) //data not divisible by 24 bit
            encodedData = new byte[ (numberTriplets + 1 )*4  ];
        else // 16 or 8 bit
            encodedData = new byte[ numberTriplets*4 ];

        byte k=0, l=0, b1=0,b2=0,b3=0;

        int encodedIndex = 0;
        int dataIndex   = 0;
        int i           = 0;
        for ( i = 0; i<numberTriplets; i++ ) {

            dataIndex = i*3;
            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            b3 = binaryData[dataIndex + 2];

            l  = (byte)(b2 & 0x0f);
            k  = (byte)(b1 & 0x03);

            encodedIndex = i*4;
            encodedData[encodedIndex]   = lookUpBase64Alphabet[ b1 >>2 ];
            encodedData[encodedIndex+1] = lookUpBase64Alphabet[(b2 >>4 ) |
( k<<4 )];
            encodedData[encodedIndex+2] = lookUpBase64Alphabet[ (l <<2 ) |
( b3>>6)];
            encodedData[encodedIndex+3] = lookUpBase64Alphabet[ b3 & 0x3f ];
        }

        // form integral number of 6-bit groups
        dataIndex    = i*3;
        encodedIndex = i*4;
        if (fewerThan24bits == EIGHTBIT ) {
            b1 = binaryData[dataIndex];
            k = (byte) ( b1 &0x03 );
            encodedData[encodedIndex]     = lookUpBase64Alphabet[ b1 >>2 ];
            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 );
            encodedData[encodedIndex]     = lookUpBase64Alphabet[ b1 >>2 ];
            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[ (b2 >>4 )
| ( k<<4 )];
            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[ l<<2 ];
            encodedData[encodedIndex + 3] = PAD;
        }
        return encodedData;
static booleanisArrayByteBase64(byte[] arrayOctect)

        int length = arrayOctect.length;
        if ( length == 0 )
            return false;
        for ( int i=0; i < length; i++ ) {
            if ( Base64.isBase64( arrayOctect[i] ) == false)
                return false;
        }
        return true;
static booleanisBase64(byte octect)


     

        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] = (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 );

    
        //shall we ignore white space? JEFF??
        return(octect == PAD || base64Alphabet[octect] != -1 );