alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Tomcat example source code file (Base64.java)

This example Tomcat source code file (Base64.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

a, eightbit, eightbit, fourbyte, no, pad, pad, sixteenbit, string, string, stringbuffer, twentyfourbitgroup, twentyfourbitgroup, wrong

The Tomcat Base64.java source code

/*
 *  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 org.apache.tomcat.util.buf;


/**
 * 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: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */

public final class Base64 {


    private static org.apache.juli.logging.Log log=
        org.apache.juli.logging.LogFactory.getLog( Base64.class );
    
    static private final int  BASELENGTH         = 255;
    static private final int  LOOKUPLENGTH       = 63;
    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 byte PAD               = ( byte ) '=';
    static private byte [] base64Alphabet       = new byte[BASELENGTH];
    static private byte [] lookUpBase64Alphabet = new byte[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] = (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 );

    }


    static boolean isBase64( byte octect ) {
        //shall we ignore white space? JEFF??
        return(octect == PAD || base64Alphabet[octect] != -1 );
    }


    static boolean isArrayByteBase64( 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;
    }

    /**
     * Encodes hex octects into Base64
     *
     * @param binaryData Array containing binaryData
     * @return Encoded Base64 array
     */
    public static byte[] encode( byte[] binaryData ) {
        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;
    }


    /**
     * Decodes Base64 data into octects
     *
     * @param base64Data Byte array containing Base64 data
     * @return Array containind decoded data.
     */
    public byte[] decode( byte[] base64Data ) {
        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;

    }

    static final int base64[]= {
	64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
	    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
	    64,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
	    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
	    64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
	    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
	    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
    };

    public static String base64Decode( 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();
    }


}

Other Tomcat examples (source code examples)

Here is a short list of links related to this Tomcat Base64.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.