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/*
 * 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.catalina.util;

import java.io.UnsupportedEncodingException;

import org.apache.tomcat.util.buf.B2CConverter;
import org.apache.tomcat.util.buf.ByteChunk;
import org.apache.tomcat.util.buf.CharChunk;

/**
 * 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
 *
 * @author Jeffrey Rodriguez
 * @version $Id: Base64.java 1140463 2011-06-28 07:22:28Z markt $
 */
public final class  Base64
{
    private static final int  BASELENGTH         = 255;
    private static final int  LOOKUPLENGTH       = 64;
    private static final int  TWENTYFOURBITGROUP = 24;
    private static final int  EIGHTBIT           = 8;
    private static final int  SIXTEENBIT         = 16;
    private static final int  FOURBYTE           = 4;
    private static final int  SIGN               = -128;
    private static final byte PAD                = (byte) '=';
    private static byte [] base64Alphabet       = new byte[BASELENGTH];
    private static 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);

        lookUpBase64Alphabet[62] = (byte) '+';
        lookUpBase64Alphabet[63] = (byte) '/';
    }

    /**
     * Encodes hex octets into Base64.
     *
     * @param binaryData Array containing binary data to encode.
     * @return Base64-encoded data.
     */
    public static String 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;
        //log.debug("number of triplets = " + numberTriplets);
        for ( i = 0; i