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A slightly adapted version of Xerces 2.11.0 to allow the XMLStringBuffer responsible for XML attribute scanning to start larger and thus avoid extended appending times. The initial buffer size is controlled by settting the system property julielab.xerces.attributebuffersize (also available as constant XMLScanner#ATTRIBUTE_BUFFER_SIZE).

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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.xerces.impl.dv.util;

/**
 * format validation
 *
 * This class encodes/decodes hexadecimal data
 * 
 * @xerces.internal  
 * 
 * @author Jeffrey Rodriguez
 * @version $Id: HexBin.java 446747 2006-09-15 21:46:20Z mrglavas $
 */
public final class  HexBin {
    static private final int  BASELENGTH   = 128;
    static private final int  LOOKUPLENGTH = 16;
    static final private byte [] hexNumberTable    = new byte[BASELENGTH];
    static final private char [] lookUpHexAlphabet = new char[LOOKUPLENGTH];


    static {
        for (int i = 0; i < BASELENGTH; i++ ) {
            hexNumberTable[i] = -1;
        }
        for ( int i = '9'; i >= '0'; i--) {
            hexNumberTable[i] = (byte) (i-'0');
        }
        for ( int i = 'F'; i>= 'A'; i--) {
            hexNumberTable[i] = (byte) ( i-'A' + 10 );
        }
        for ( int i = 'f'; i>= 'a'; i--) {
           hexNumberTable[i] = (byte) ( i-'a' + 10 );
        }

        for(int i = 0; i<10; i++ ) {
            lookUpHexAlphabet[i] = (char)('0'+i);
        }
        for(int i = 10; i<=15; i++ ) {
            lookUpHexAlphabet[i] = (char)('A'+i -10);
        }
    }

    /**
     * Encode a byte array to hex string
     *
     * @param binaryData array of byte to encode
     * @return return encoded string
     */
    static public String encode(byte[] binaryData) {
        if (binaryData == null)
            return null;
        int lengthData   = binaryData.length;
        int lengthEncode = lengthData * 2;
        char[] encodedData = new char[lengthEncode];
        int temp;
        for (int i = 0; i < lengthData; i++) {
            temp = binaryData[i];
            if (temp < 0)
                temp += 256;
            encodedData[i*2] = lookUpHexAlphabet[temp >> 4];
            encodedData[i*2+1] = lookUpHexAlphabet[temp & 0xf];
        }
        return new String(encodedData);
    }

    /**
     * Decode hex string to a byte array
     *
     * @param encoded encoded string
     * @return return array of byte to encode
     */
    static public byte[] decode(String encoded) {
        if (encoded == null)
            return null;
        int lengthData = encoded.length();
        if (lengthData % 2 != 0)
            return null;

        char[] binaryData = encoded.toCharArray();
        int lengthDecode = lengthData / 2;
        byte[] decodedData = new byte[lengthDecode];
        byte temp1, temp2;
        char tempChar;
        for( int i = 0; i