83 lines
2.8 KiB
Python
83 lines
2.8 KiB
Python
# iso6346.py - functions for handling ISO 6346
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#
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# Copyright (C) 2014 Openlabs Technologies & Consulting (P) Limited
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# Copyright (C) 2014 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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"""ISO 6346 (International standard for container identification)
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ISO 6346 is an international standard covering the coding, identification and
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marking of intermodal (shipping) containers used within containerized
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intermodal freight transport. The standard establishes a visual identification
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system for every container that includes a unique serial number (with check
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digit), the owner, a country code, a size, type and equipment category as well
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as any operational marks. The standard is managed by the International
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Container Bureau (BIC).
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>>> validate('csqu3054383')
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'CSQU3054383'
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>>> validate('CSQU3054384')
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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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import re
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from stdnum.exceptions import InvalidChecksum, InvalidFormat, InvalidLength, \
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ValidationError
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from stdnum.util import clean
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_iso6346_re = re.compile(r'^\w{3}(U|J|Z|R)\d{7}$')
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def compact(number):
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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).strip().upper()
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def calc_check_digit(number):
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"""Calculate check digit and return it for the 10 digit owner code and
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serial number."""
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number = compact(number)
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alphabet = '0123456789A BCDEFGHIJK LMNOPQRSTU VWXYZ'
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return str(sum(
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alphabet.index(n) * pow(2, i)
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for i, n in enumerate(number)) % 11)
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def validate(number):
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"""Validate the given number (unicode) for conformity to ISO 6346."""
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number = compact(number)
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if len(number) != 11:
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raise InvalidLength()
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if not _iso6346_re.match(number):
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raise InvalidFormat()
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if calc_check_digit(number[:-1]) != number[-1]:
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raise InvalidChecksum()
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return number
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def is_valid(number):
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"""Check whether the number conforms to the standard ISO6346. Unlike
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the validate function, this will not raise ValidationError(s)."""
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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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