Easy way to generate XOR checksum on a stream?

Question

In C# is there an easy way to generate an XOR checksum on a MemoryStream (binary) excluding the first, and last two, bytes?

Also, is it easier to extend the BinaryWriter and do it as the Stream is written?

Answer 1

You can use LINQ to get the answer:

var checksum = memStream
    .GetBuffer() // Get the underlying byte array
    .Skip(1)     // Skip the first byte
    .Take(memStream.Length-3) // One for the beginning, two more for the end
    .Aggregate(0, (p,v) => p ^ v); // XOR the accumulated value and the next byte