How do you convert 3 bytes into a 24 bit number in C#?

Question

I have an array of bytes that I read from a header section of a message. These bytes contain the length of the message. There never are more than 3 bytes and they are ordere

Answer 1

Something like this should work:

data[0] + 256*data[1] + 256*256*data[2]

Your compiler should optimize that to the 'right' bit twiddling operations.