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 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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 com.sun.org.apache.xerces.internal.impl.dv.util;

/**

 * format validation

 *

 * This class encodes/decodes hexadecimal data

 *

 * @xerces.internal

 *

 * @author Jeffrey Rodriguez

 */

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<lengthDecode; i++ ){

            tempChar = binaryData[i*2];

            temp1 = (tempChar < BASELENGTH) ? hexNumberTable[tempChar] : -1;

            if (temp1 == -1)

                return null;

            tempChar = binaryData[i*2+1];

            temp2 = (tempChar < BASELENGTH) ? hexNumberTable[tempChar] : -1;

            if (temp2 == -1)

                return null;

            decodedData[i] = (byte)((temp1 << 4) | temp2);

        }

        return decodedData;

    }

}