--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/contrib/localflavor/ca/forms.py	Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,126 @@
+"""
+Canada-specific Form helpers
+"""
+
+from django.newforms import ValidationError
+from django.newforms.fields import Field, RegexField, Select, EMPTY_VALUES
+from django.newforms.util import smart_unicode
+from django.utils.translation import gettext, ugettext
+import re
+
+phone_digits_re = re.compile(r'^(?:1-?)?(\d{3})[-\.]?(\d{3})[-\.]?(\d{4})$')
+sin_re = re.compile(r"^(\d{3})-(\d{3})-(\d{3})$")
+
+class CAPostalCodeField(RegexField):
+    """Canadian postal code field."""
+    default_error_messages = {
+        'invalid': gettext(u'Enter a postal code in the format XXX XXX.'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(CAPostalCodeField, self).__init__(r'^[ABCEGHJKLMNPRSTVXYZ]\d[A-Z] \d[A-Z]\d$',
+            max_length=None, min_length=None, *args, **kwargs)
+
+class CAPhoneNumberField(Field):
+    """Canadian phone number field."""
+    default_error_messages = {
+        'invalid': u'Phone numbers must be in XXX-XXX-XXXX format.',
+    }
+
+    def clean(self, value):
+        """Validate a phone number.
+        """
+        super(CAPhoneNumberField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return u''
+        value = re.sub('(\(|\)|\s+)', '', smart_unicode(value))
+        m = phone_digits_re.search(value)
+        if m:
+            return u'%s-%s-%s' % (m.group(1), m.group(2), m.group(3))
+        raise ValidationError(self.error_messages['invalid'])
+
+class CAProvinceField(Field):
+    """
+    A form field that validates its input is a Canadian province name or abbreviation.
+    It normalizes the input to the standard two-leter postal service
+    abbreviation for the given province.
+    """
+    default_error_messages = {
+        'invalid': u'Enter a Canadian province or territory.',
+    }
+
+    def clean(self, value):
+        from ca_provinces import PROVINCES_NORMALIZED
+        super(CAProvinceField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return u''
+        try:
+            value = value.strip().lower()
+        except AttributeError:
+            pass
+        else:
+            try:
+                return PROVINCES_NORMALIZED[value.strip().lower()].decode('ascii')
+            except KeyError:
+                pass
+        raise ValidationError(self.error_messages['invalid'])
+
+class CAProvinceSelect(Select):
+    """
+    A Select widget that uses a list of Canadian provinces and
+    territories as its choices.
+    """
+    def __init__(self, attrs=None):
+        from ca_provinces import PROVINCE_CHOICES # relative import
+        super(CAProvinceSelect, self).__init__(attrs, choices=PROVINCE_CHOICES)
+
+class CASocialInsuranceNumberField(Field):
+    """
+    A Canadian Social Insurance Number (SIN).
+
+    Checks the following rules to determine whether the number is valid:
+
+        * Conforms to the XXX-XXX-XXX format.
+        * Passes the check digit process "Luhn Algorithm"
+             See: http://en.wikipedia.org/wiki/Social_Insurance_Number
+    """
+    default_error_messages = {
+        'invalid': ugettext('Enter a valid Canadian Social Insurance number in XXX-XXX-XXX format.'),
+    }
+
+    def clean(self, value):
+        super(CASocialInsuranceNumberField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return u''
+
+        match = re.match(sin_re, value)
+        if not match:
+            raise ValidationError(self.error_messages['invalid'])
+
+        number = u'%s-%s-%s' % (match.group(1), match.group(2), match.group(3))
+        check_number = u'%s%s%s' % (match.group(1), match.group(2), match.group(3))
+        if not self.luhn_checksum_is_valid(check_number):
+            raise ValidationError(self.error_messages['invalid'])
+        return number
+
+    def luhn_checksum_is_valid(self, number):
+        """
+        Checks to make sure that the SIN passes a luhn mod-10 checksum
+        See: http://en.wikipedia.org/wiki/Luhn_algorithm
+        """
+
+        sum = 0
+        num_digits = len(number)
+        oddeven = num_digits & 1
+
+        for count in range(0, num_digits):
+            digit = int(number[count])
+
+            if not (( count & 1 ) ^ oddeven ):
+                digit = digit * 2
+            if digit > 9:
+                digit = digit - 9
+
+            sum = sum + digit
+
+        return ( (sum % 10) == 0 )