mbirth/gcd-parser
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Improved output of gcksum.

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This commit is contained in:
Markus Birth 2018-10-14 23:25:32 +02:00
parent 6da125adbe
commit 98ca35501c
Signed by: mbirth
GPG Key ID: A9928D7A098C3A9A
1 changed files with 9 additions and 1 deletions

10
gcksum.py

@ -11,6 +11,7 @@ print("Opening {}".format(FILE))
csum_pre = 0 csum_pre = 0
csum = 0 csum = 0
last_byte = 0xff
with open(FILE, "rb") as f: with open(FILE, "rb") as f:
while True: while True:
@ -21,11 +22,18 @@ with open(FILE, "rb") as f:
csum &= 0xff csum &= 0xff
if len(block) < 1024: if len(block) < 1024:
print("End reached.") print("End reached.")
last_byte = unpack("B", block[-1:])[0]
break break
print("Sum of all bytes: {:02x}".format(csum)) print("Sum of all bytes: {:02x}".format(csum))
print("Sum without last: {:02x}".format(csum_pre)) if csum == 0:
print("CHECKSUM VALID.")
else:
print("CHECKSUM INVALID!!! (Or GCD or other type.)")
#print("Sum without last: {:02x}".format(csum_pre))
expected_cksum = ( 0x100 - csum_pre ) & 0xff expected_cksum = ( 0x100 - csum_pre ) & 0xff
print("Expected last byte: {:02x}".format(expected_cksum)) print("Expected last byte: {:02x}".format(expected_cksum))
print("Actual last byte: {:02x}".format(last_byte))