Mega Code Archive
Convert 4 hex digits to an int, and return the number of converted bytes
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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.
*/
import java.io.ByteArrayOutputStream;
/**
* Library of utility methods useful in dealing with converting byte arrays to
* and from strings of hexadecimal digits.
*
* @author Craig R. McClanahan
*/
public final class HexUtils {
// Code from Ajp11, from Apache's JServ
// Table for HEX to DEC byte translation
public static final int[] DEC = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, 00, 01, 02, 03, 04, 05, 06, 07, 8, 9, -1, -1, -1, -1, -1,
-1, -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, };
/**
* Convert 4 hex digits to an int, and return the number of converted bytes.
*
* @param hex
* Byte array containing exactly four hexadecimal digits
*
* @exception IllegalArgumentException
* if an invalid hexadecimal digit is included
*/
public static int convert2Int(byte[] hex) {
// Code from Ajp11, from Apache's JServ
// assert b.length==4
// assert valid data
int len;
if (hex.length < 4)
return 0;
if (DEC[hex[0]] < 0)
throw new IllegalArgumentException("hexUtil.bad");
len = DEC[hex[0]];
len = len << 4;
if (DEC[hex[1]] < 0)
throw new IllegalArgumentException("hexUtil.bad");
len += DEC[hex[1]];
len = len << 4;
if (DEC[hex[2]] < 0)
throw new IllegalArgumentException("hexUtil.bad");
len += DEC[hex[2]];
len = len << 4;
if (DEC[hex[3]] < 0)
throw new IllegalArgumentException("hexUtil.bad");
len += DEC[hex[3]];
return len;
}
}
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