79 lines
2.4 KiB
Python
79 lines
2.4 KiB
Python
# rnc.py - functions for handling Dominican Republic tax registration
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#
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# Copyright (C) 2015 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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"""RNC (Registro Nacional del Contribuyente, Dominican Republic tax number).
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The RNC is the Dominican Republic taxpayer registration number for
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institutions. The number consists of 9 digits.
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>>> validate('1-01-85004-3')
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'101850043'
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>>> validate('1018A0043')
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Traceback (most recent call last):
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...
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InvalidFormat: ...
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>>> validate('101850042')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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>>> format('131246796')
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'1-31-24679-6'
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"""
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from stdnum.exceptions import *
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from stdnum.util import clean
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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()
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def calc_check_digit(number):
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"""Calculate the check digit."""
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weights = (7, 9, 8, 6, 5, 4, 3, 2)
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check = sum(w * int(n) for w, n in zip(weights, number)) % 11
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return str((10 - check) % 9 + 1)
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def validate(number):
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"""Checks to see if the number provided is a valid RNC."""
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number = compact(number)
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if len(number) != 9:
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raise InvalidLength()
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if not number.isdigit():
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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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"""Checks to see if the number provided is a valid RNC."""
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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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def format(number):
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"""Reformat the passed number to the standard format."""
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number = compact(number)
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return '-'.join((number[:1], number[1:3], number[3:-1], number[-1]))
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