Convert bytes to bits in python

Question

I am working with Python3.2. I need to take a hex stream as an input and parse it at bit-level. So I used

bytes.fromhex(input_str)

to convert t

Answer 1

Operations are much faster when you work at the integer level. In particular, converting to a string as suggested here is really slow.

If you want bit 7 and 8 only, use e.g.

val = (byte >> 6) & 3

(this is: shift the byte 6 bits to the right - dropping them. Then keep only the last two bits 3 is the number with the first two bits set...)

These can easily be translated into simple CPU operations that are super fast.