gcksum.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
Calculates the Byte-checksum of a file and
shows if it's (last Byte) correct or not.
"""

from grmn import ChkSum
import sys

FILE = sys.argv[1]

csum = ChkSum()
print("Reading {} ...".format(FILE), end="", flush=True)
csum.add_from_file(FILE, print_progress=True)
print(" done.")

print("Sum of all bytes: {:02x}".format(csum.get_sum()))
print("Last byte: {:02x}".format(csum.get_last_byte()))
if csum.is_valid():
    print("☑ CHECKSUM VALID.")
else:
    print("☒ CHECKSUM INVALID!!! (Or GCD or other type.)")
    expected_cksum = csum.get_expected()
    print("Expected last byte: {:02x}".format(expected_cksum))