MathTools.java

package com.firstbuild.tools;

/**
 * Created by hans on 16. 7. 7..
 */
public class MathTools {

    // hex to byte[]
    public static byte[] hexToByteArray(String hex) {
        if (hex == null || hex.length() == 0) {
            return null;
        }

        byte[] ba = new byte[hex.length() / 2];
        for (int i = 0; i < ba.length; i++) {
            ba[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);
        }
        return ba;
    }

    /**
     * Convert byte Array to HEX decimal
     * Converted value's Byte Order starts from the left. Left value is lower byte to the Right value
     * @param ba byte array to convert
     * @return Converted Hexa Decimal value
     */
    public static String byteArrayToHex(byte[] ba) {
        if (ba == null || ba.length == 0) {
            return null;
        }

        StringBuffer sb = new StringBuffer(ba.length * 2);
        String hexNumber;
        for (int x = 0; x < ba.length; x++) {
            hexNumber = "0" + Integer.toHexString(0xff & ba[x]);

            sb.append(hexNumber.substring(hexNumber.length() - 2));
        }
        return sb.toString();
    }

    public static int hexByteToInt(byte b) {
        return Integer.parseInt(Byte.toString(b), 16);
    }
}