C# - are byte representations of different types different?

Question

I know question is a bit weird, I'm asking out of pure curiosity, as I couldn't find any relevant info around. Also, please feel free to edit title, I know its terrible, but could not make up any better.

Let say I have variable foo of type object, which is either short or ushort. I need to send it over network, so I use BitConverter to transform it into byte[]:

byte[] b = new byte[2];
if(foo is short){
    BitConverter.GetBytes((short)foo, 0);
}else{
    BitConverter.GetBytes((ushort)foo, 0);
}

Network/Socket magic happens, I want my variable back. I know type I am expecting to get, so I call BitConverter.GetUInt16 or GetInt16 properly.

Now, question is - does it actually matter, how I serialized the variable? I mean, bits are the same, so it shouldn't have any meaning, am I correct? So that I could

BitConverter.GetBytes((short)foo, 0);

and then do

BitConverter.GetUInt16(myByteArray, 0);

Anyone?

Answer 1

To serialize your variable, you should assign the result of BitConverter.GetBytes() to your byte[]. It doesn't matter if your variable is short or ushort, as those are the same size and hold the same values between 0 and 32767. As long as the size is ok, you should have no problems.

So you may make your code as simple as this:

byte[] b;
if(foo is short || foo is ushort)
    b = BitConverter.GetBytes((short)foo); // You get proper results for ushort as well

However at the decoding site you must know which type you need, for short, you need:

short foo = BitConverter.ToInt16(b, 0);

but if you need an ushort, then you write:

ushort foo = BitConverter.ToUInt16(b, 0);

When you send multibyte variables over the network, you should also ensure that they are in network byte order as @itsme86 mentioned in his answer.

If you need to send both shorts and ushorts, then you also need to send type information to the other end to know if the data type is signed or not. I don't write about it now in detail as it would complicate the code.