Thread: Converting a piece of C# code to Java (unsigned longs, etc)

Hello!

I'm trying to convert this piece of C# code to java, but I'm stumbling to problems because java doesn't seem to have unsigned long.

public static string keyHexToKey(byte[] keyHex)
{
        string arg = "";
        string text = "0123456789ABCDEFGHJKLMNPRSTVWXYZ";
        for (int i = 0; i < 3; i++)
        {
                ulong num = 0uL;
                for (int j = 0; j < 5; j++)
                {
                        num <<= 8;
                        num |= (ulong)keyHex[i * 5 + j];
                }
                for (int j = 0; j < 8; j++)
                {
                        ulong num2 = num >> j * 5 & 31uL;
                        char c = text[(int)num2];
                        arg += c;
                }
        }
        return arg;
}

What I came up by myself, but doesn't seem to work (return wrong values).

private static String keyHexToKey(byte[] keyHex)
	{
	        String arg = "";
	        String text = "0123456789ABCDEFGHJKLMNPRSTVWXYZ";
	        char[] text2 = text.toCharArray();
 
	        for (int i = 0; i < 3; i++)
	        {
	                //long num = 0uL;
	        		long num = (long)0xff;
	                for (int j = 0; j < 5; j++)
	                {
	                        num <<= 8;
	                        num |= (long)keyHex[i * 5 + j];
	                }
	                for (int j = 0; j < 8; j++)
	                {
	                        long num2 = num >> j * 5 & (long)31;
	                        //char c = text[(int)num2];
	                        char c = text2[(int)num2];
	                        arg += c;
	                }
	        }
	        return arg;
	}

In Java a Long is a signed 64 bit value, and Java doesn't offer an unsigned version of this as they believe unsigned integers to be wrong, the only unsigned data type is a char.

Also you do not need to cast literals to long, simple append "L" such as 32L would be the long value for 32.

Your options are either, manually handle the sign, or use the BigInteger class

BigInteger (Java Platform SE 7 )

Chris