coolstuff.py

import math

def print_bin(data):
    print (format(data, '08b'))

def swap_twos_comp(data, size):
    return (~data & ((0x1 << size) - 1)) + 1 # apply twos complement

def py_to_unsigned(data, outputBits):

    if data < 0: # check for negitive and apply signage
        # make data positive, then swap positive to negitive twos complement
        data = swap_twos_comp(-data, outputBits)
    else:
        data &= (0x1 << outputBits) - 1 # truncate to bitsize
    return data

def unsigned_to_py(data):

    bl = data.bit_length()

    if data & (0x1 << bl-1): # signed data
        data = -1*swap_twos_comp(data, bl) # convert out of twos complement

    return data

def split_to_char(data, byteSize, signed=False):
    if signed:
        data = py_to_unsigned(data, byteSize*8)
    else:
        byteActual = data.bit_length()

    mask = (0x1 << 8) - 1

    bytesStr = bytearray()
    for i in range(byteSize):
        if not signed and (8*i) > byteActual:
             # we dont need to worry about signed values because
             # `int_to_unsigned` pads the signed values properly
             # so this will only happen for unsigned ints
            bytesStr.append(0x00)
        else:
            # Here we move the mask over by the shift value
            # mask the data value, and shift it all back to get the next byte.
            bytesStr.append((data >> (8*i)) & mask)
    return bytesStr

def chars_to_unsigned(data, outputBits):
    output = 0
    for i, d in enumerate(data):
        output |= d << (i*8)
    return output & ((0x1 << outputBits) - 1)