Java Hex Convert To fromHex(CharSequence cs)

Description

Converts a character sequence of hexadecimal characters to byte array.

License

Apache License

Parameter

Parameter	Description
cs	the char sequence, the length must be even

Return

the byte array output

Declaration

public static byte[] fromHex(CharSequence cs) 

Method Source Code

//package com.java2s;
/*//  ww w . j  av  a 2  s  . c  om
 * Copyright 2012-2014 David Karnok
 *
 * Licensed 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.
 */

public class Main {
    /**
     * Converts a character sequence of hexadecimal characters
     * to byte array.
     * @param cs the char sequence, the length must be even
     * @return the byte array output
     */
    public static byte[] fromHex(CharSequence cs) {
        if (cs.length() % 2 != 0) {
            throw new IllegalArgumentException("Odd length: " + cs.length());
        }
        byte[] r = new byte[cs.length() / 2];
        for (int i = 0; i < r.length; i++) {
            r[i] = (byte) ((fromHex(cs.charAt(i * 2)) << 4) | fromHex(cs.charAt(i * 2 + 1)));
        }
        return r;
    }

    /**
     * Convert a hexadecimal character into a number.
     * @param c the character, 0-9a-fA-F
     * @return the decimal value
     */
    private static int fromHex(char c) {
        if (c >= '0' && c <= '9') {
            return c - '0';
        }
        if (c >= 'a' && c <= 'f') {
            return c - 'a' + 10;
        }
        if (c >= 'A' && c <= 'F') {
            return c - 'A' + 10;
        }
        throw new IllegalArgumentException("Not a hex char: " + c);
    }
}

Related

1. convertHexToFloat(long hexValue)
2. fromHex(byte[] hex)
3. fromHex(char c)
4. fromHex(char c)
5. fromHex(char hi, char lo)
6. fromHex(final CharSequence s)
7. fromHex(final String hex)
8. fromHex(final String hex)
9. fromHex(final String hexValue)