mbirth/gcd-parser
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More output after checksum calc.

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This commit is contained in:
Markus Birth 2018-10-14 22:45:16 +02:00
parent 90957931f2
commit 6da125adbe
Signed by: mbirth
GPG Key ID: A9928D7A098C3A9A
1 changed files with 8 additions and 1 deletions
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9
gcksum.py
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@ -9,16 +9,23 @@ FILE = sys.argv[1]
print("Opening {}".format(FILE)) print("Opening {}".format(FILE))
csum_pre = 0
csum = 0 csum = 0
with open(FILE, "rb") as f: with open(FILE, "rb") as f:
while True: while True:
block = f.read(1024) block = f.read(1024)
for c in block: for c in block:
csum_pre = csum
csum += c csum += c
csum &= 0xff csum &= 0xff
if len(block) < 1024: if len(block) < 1024:
print("End reached.") print("End reached.")
break break
print("Sum of all bytes: {}".format(csum)) print("Sum of all bytes: {:02x}".format(csum))
print("Sum without last: {:02x}".format(csum_pre))
expected_cksum = ( 0x100 - csum_pre ) & 0xff
print("Expected last byte: {:02x}".format(expected_cksum))