Java Socket vs. C# TcpClient

Question

I am converting a Java application into C# and I have a general question regarding the underlying stream of bytes.

A 'byte' is unsigned in C# as opposed to signed in Java.

What does this do to parts of my code where I am comparing bytes for equivalency. For example:

Java code

public final static byte IAC = (byte)255;
...
void parseBuffer(byte[] bb, int len) {
    try {
        for(int i = 0;i < len; i++) {
            if(bb[i] == IAC)
                DoSomething();
        }
    }
}

Do I need to do anything to the declaration of the IAC variable? Would it be anything other then (byte)255?

Thanks for your help in advance.

Answer 1

Do I need to do anything to the declaration of the IAC variable?

No. It's absolutely fine. You'll end up with a value of -1 for IAC, but that's fine and still represents a byte with all bits set. If you send a byte of value 255 from the C# side, it will be picked up correctly on the Java side.

Another alternative would be to work with a larger data type (e.g. int for convenience, and use bitmasking to end up with a value in the range [0, 255]:

public static final int IAC = 255;
...
void parseBuffer(byte[] bb, int len) {
    try {
        for(int i = 0; i < len; i++) {
            int value = bb[i] & 0xff; // To get a value in the range [0, 255]
            if (value == IAC) {
                DoSomething();
            }
        }
    }
}