Hy-Tek Checksum Functions

checksum.py

def calculate_hy3_sum(line: str) -> int:
    data = "{:<128}".format(line)  # pad to 128 chars

    odd_sum = sum([ord(data[c]) for c in range(0, len(data), 2)])  # sum odd chars
    even_sum = sum([ord(data[c]) for c in range(1, len(data), 2)])  # sum even chars
    checksum = math.trunc((odd_sum + 2 * even_sum) / 21)  # add odd + 2 * even, then /21, ignore decimal
    checksum += 205  # add 205 to result
    checksum = int(str(checksum)[:-3:-1])  # take last 2 digits of result and reverse

    return checksum
  
def calculate_cl2_sum(cls, line: str) -> str:
    data = "{:<156}".format(line)  # pad to 156 chars

    char_sum = sum([ord(data[c]) for c in range(0, len(data))])  # sum chars
    # even_sum = sum([ord(data[c]) for c in range(1, len(data), 2)])  # sum even chars
    checksum = math.trunc(char_sum/19)  # divide char sum by 21, ignore decimal
    checksum += 211  # add 211 to result
    checksum = str(checksum)[:-3:-1]  # take last 2 digits of result and reverse

    prefix = " "
    # if data[:2] == "D0":
    #     prefix = "N"

    return "{}N{}".format(prefix, checksum)