86 lines
2.7 KiB
Python
86 lines
2.7 KiB
Python
# abn.py - functions for handling Australian Business Numbers (ABNs)
|
|
#
|
|
# Copyright (C) 2016 Vincent Bastos
|
|
# Copyright (C) 2016 Arthur de Jong
|
|
#
|
|
# This library is free software; you can redistribute it and/or
|
|
# modify it under the terms of the GNU Lesser General Public
|
|
# License as published by the Free Software Foundation; either
|
|
# version 2.1 of the License, or (at your option) any later version.
|
|
#
|
|
# This library is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
# Lesser General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU Lesser General Public
|
|
# License along with this library; if not, write to the Free Software
|
|
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
# 02110-1301 USA
|
|
|
|
"""ABN (Australian Business Number).
|
|
|
|
The Australian Business Number (ABN) is an identifier issued to entities
|
|
registered in the Australian Business Register (ABR). The number consists of
|
|
11 digits of which the first two are check digits.
|
|
|
|
More information:
|
|
|
|
* https://en.wikipedia.org/wiki/Australian_Business_Number
|
|
* https://abr.business.gov.au/
|
|
|
|
>>> validate('83 914 571 673')
|
|
'83914571673'
|
|
>>> validate('99 999 999 999')
|
|
Traceback (most recent call last):
|
|
...
|
|
InvalidChecksum: ...
|
|
>>> format('51824753556')
|
|
'51 824 753 556'
|
|
"""
|
|
|
|
from __future__ import annotations
|
|
|
|
from stdnum.exceptions import *
|
|
from stdnum.util import clean, isdigits
|
|
|
|
|
|
def compact(number: str) -> str:
|
|
"""Convert the number to the minimal representation. This strips the
|
|
number of any valid separators and removes surrounding whitespace."""
|
|
return clean(number, ' ').strip()
|
|
|
|
|
|
def calc_check_digits(number: str) -> str:
|
|
"""Calculate the check digits that should be prepended to make the number
|
|
valid."""
|
|
weights = (3, 5, 7, 9, 11, 13, 15, 17, 19)
|
|
s = sum(-w * int(n) for w, n in zip(weights, number))
|
|
return str(11 + (s - 1) % 89)
|
|
|
|
|
|
def validate(number: str) -> str:
|
|
"""Check if the number is a valid ABN. This checks the length, formatting
|
|
and check digit."""
|
|
number = compact(number)
|
|
if not isdigits(number):
|
|
raise InvalidFormat()
|
|
if len(number) != 11:
|
|
raise InvalidLength()
|
|
if calc_check_digits(number[2:]) != number[:2]:
|
|
raise InvalidChecksum()
|
|
return number
|
|
|
|
|
|
def is_valid(number: str) -> bool:
|
|
"""Check if the number is a valid ABN."""
|
|
try:
|
|
return bool(validate(number))
|
|
except ValidationError:
|
|
return False
|
|
|
|
|
|
def format(number: str) -> str:
|
|
"""Reformat the number to the standard presentation format."""
|
|
number = compact(number)
|
|
return ' '.join((number[0:2], number[2:5], number[5:8], number[8:]))
|