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Shared/lib/python3.4/site-packages/stdnum/iban.py

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+# iban.py - functions for handling International Bank Account Numbers (IBANs)
+#
+# Copyright (C) 2011, 2012, 2013 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
+
+"""IBAN (International Bank Account Number).
+
+The IBAN is used to identify bank accounts across national borders. The
+first two letters are a country code. The next two digits are check digits
+for the ISO 7064 Mod 97, 10 checksum. Each country uses it's own format
+for the remainder of the number.
+
+Some countries may also use checksum algorithms within their number but
+this is currently not checked by this number.
+
+>>> validate('GR16 0110 1050 0000 1054 7023 795')
+'GR1601101050000010547023795'
+>>> validate('BE31435411161155')
+'BE31435411161155'
+>>> compact('GR16 0110 1050 0000 1054 7023 795')
+'GR1601101050000010547023795'
+>>> format('GR1601101050000010547023795')
+'GR16 0110 1050 0000 1054 7023 795'
+"""
+
+import re
+
+from stdnum import numdb
+from stdnum.exceptions import *
+from stdnum.iso7064 import mod_97_10
+from stdnum.util import clean
+
+
+# our open copy of the IBAN database
+_ibandb = numdb.get('iban')
+
+# the valid characters we have
+_alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+
+# regular expression to check IBAN structure
+_struct_re = re.compile('([1-9][0-9]*)!([nac])')
+
+
+def compact(number):
+    """Convert the iban number to the minimal representation. This strips the
+    number of any valid separators and removes surrounding whitespace."""
+    return clean(number, ' -').strip().upper()
+
+
+def _to_base10(number):
+    """Prepare the number to it's base10 representation (also moving the
+    check digits to the end) so it can be checked with the ISO 7064
+    Mod 97, 10 algorithm."""
+    # TODO: find out whether this should be in the mod_97_10 module
+    return ''.join(str(_alphabet.index(x)) for x in number[4:] + number[:4])
+
+
+def _struct_to_re(structure):
+    """Convert an IBAN structure to a refular expression that can be used
+    to validate the number."""
+    def conv(match):
+        chars = {
+            'n': '[0-9]',
+            'a': '[A-Z]',
+            'c': '[A-Za-z0-9]',
+        }[match.group(2)]
+        return '%s{%s}' % (chars, match.group(1))
+    return re.compile('^%s$' % _struct_re.sub(conv, structure))
+
+
+def validate(number):
+    """Checks to see if the number provided is a valid IBAN."""
+    number = compact(number)
+    try:
+        test_number = _to_base10(number)
+    except:
+        raise InvalidFormat()
+    # ensure that checksum is valid
+    mod_97_10.validate(test_number)
+    # look up the number
+    info = _ibandb.info(number)
+    # check if the bban part of number has the correct structure
+    bban = number[4:]
+    if not _struct_to_re(info[0][1].get('bban', '')).match(bban):
+        raise InvalidFormat()
+    # return the compact representation
+    return number
+
+
+def is_valid(number):
+    """Checks to see if the number provided is a valid IBAN."""
+    try:
+        return bool(validate(number))
+    except ValidationError:
+        return False
+
+
+def format(number, separator=' '):
+    """Reformat the passed number to the space-separated format."""
+    number = compact(number)
+    return separator.join(number[i:i + 4] for i in range(0, len(number), 4))