EVOLUTION-MANAGER

Edit File: checksums.py

""" Common checksum routines. """ __all__ = ['luhn',] from django.utils import six LUHN_ODD_LOOKUP = (0, 2, 4, 6, 8, 1, 3, 5, 7, 9) # sum_of_digits(index * 2) def luhn(candidate): """ Checks a candidate number for validity according to the Luhn algorithm (used in validation of, for example, credit cards). Both numeric and string candidates are accepted. """ if not isinstance(candidate, six.string_types): candidate = str(candidate) try: evens = sum([int(c) for c in candidate[-1::-2]]) odds = sum([LUHN_ODD_LOOKUP[int(c)] for c in candidate[-2::-2]]) return ((evens + odds) % 10 == 0) except ValueError: # Raised if an int conversion fails return False