mbirth/ninty-codes
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Update checksum calculation and make it work for B and C codes.

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This commit is contained in:
Markus Birth 2020-02-24 14:05:09 +01:00
parent d8a2664830
commit a30ce98607
Signed by: mbirth
GPG Key ID: A9928D7A098C3A9A
1 changed files with 7 additions and 5 deletions
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ninty-codes.py
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@ -112,11 +112,11 @@ def safe2real(code: str):
code = code.replace('Y', 'O') # O might be confused with 0 code = code.replace('Y', 'O') # O might be confused with 0
return code return code
def generateChecksum(base_code): def generateChecksum(base_code, base = 30):
if len(base_code) != 15: if len(base_code) != 15:
raise RuntimeError("Bad argument to checksum") raise RuntimeError("Bad argument to checksum")
# Mystery/bug: Why is this ord('7') in particular? 55, 0o55 and 0x55 are all unrelated to anything in base 33. The check looks like it's trying to do c - 'A', but does the weirdest thing instead. # https://www.reddit.com/r/SwitchHacks/comments/f7psrk/anatomy_of_an_eshop_card_code/fijt5d4/
cksum = reduce(lambda cksum, c: (cksum + (ord(c) - ord('0') if ord(c) <= ord('9') else ord(c) - ord('7'))) % 33, base_code, 0) cksum = sum(int(c, base) for c in base_code) % base
return CHARSET[cksum] return CHARSET[cksum]
def validate(code): def validate(code):
@ -124,7 +124,9 @@ def validate(code):
# Make uppercase if necessary, then change X and Y back to their base 33 equivalents # Make uppercase if necessary, then change X and Y back to their base 33 equivalents
unmangled_code = safe2real(code) unmangled_code = safe2real(code)
theirs = unmangled_code[15] theirs = unmangled_code[15]
mine = generateChecksum(unmangled_code[0:15]) code_type = get_type(code)
base = 33 if code_type == '_A_' else 30
mine = generateChecksum(unmangled_code[0:15], base)
return theirs == mine return theirs == mine
def parse(code): def parse(code):
@ -173,7 +175,7 @@ if __name__ == '__main__':
seen_chars[code_type] = set() seen_chars[code_type] = set()
for c in s[1:]: for c in s[1:]:
seen_chars[code_type].add(c) seen_chars[code_type].add(c)
if code_type == '_A_': if code_type != 'NUM':
valid = validate(s) valid = validate(s)
print('{} {}'.format(s, "☑ " if valid else "☒ "), end='') print('{} {}'.format(s, "☑ " if valid else "☒ "), end='')
if not valid: if not valid: