74 lines
2.3 KiB
Python
74 lines
2.3 KiB
Python
# banknote.py - functions for handling Euro banknote serial numbers
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#
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# Copyright (C) 2017 Arthur de Jong
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301 USA
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"""Euro banknote serial numbers.
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The serial number consists of one letter and 11 digits, or two letters and 10
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digits for the new series banknotes.
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More information:
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* https://en.wikipedia.org/wiki/Euro_banknotes#Serial_number
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>>> validate('P36007033744')
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'P36007033744'
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>>> validate('P36007033743')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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"""
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from __future__ import annotations
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from stdnum.exceptions import *
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from stdnum.util import clean, isdigits
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def compact(number: str) -> str:
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"""Convert the number to the minimal representation. This strips the
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number of any valid separators and removes surrounding whitespace."""
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return clean(number, ' ').upper().strip()
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def checksum(number: str) -> int:
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"""Calculate the checksum over the number."""
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# replace letters by their ASCII number
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return sum(int(x) if isdigits(x) else ord(x) for x in number) % 9
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def validate(number: str) -> str:
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"""Check if the number is a valid banknote serial number."""
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number = compact(number)
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if not number[:2].isalnum() or not isdigits(number[2:]):
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raise InvalidFormat()
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if len(number) != 12:
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raise InvalidLength()
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if number[0] not in 'BCDEFGHJLMNPRSTUVWXYZ':
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raise InvalidComponent()
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if checksum(number) != 0:
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raise InvalidChecksum()
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return number
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def is_valid(number: str) -> bool:
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"""Check if the number is a valid banknote serial number."""
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try:
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return bool(validate(number))
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except ValidationError:
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return False
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