--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/contrib/localflavor/za/forms.py	Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,59 @@
+"""
+South Africa-specific Form helpers
+"""
+
+from django.newforms import ValidationError
+from django.newforms.fields import Field, RegexField, EMPTY_VALUES
+from django.utils.checksums import luhn
+from django.utils.translation import gettext as _
+import re
+from datetime import date
+
+id_re = re.compile(r'^(?P<yy>\d\d)(?P<mm>\d\d)(?P<dd>\d\d)(?P<mid>\d{4})(?P<end>\d{3})')
+
+class ZAIDField(Field):
+    """A form field for South African ID numbers -- the checksum is validated
+    using the Luhn checksum, and uses a simlistic (read: not entirely accurate)
+    check for the birthdate
+    """
+    default_error_messages = {
+        'invalid': _(u'Enter a valid South African ID number'),
+    }
+
+    def clean(self, value):
+        # strip spaces and dashes
+        value = value.strip().replace(' ', '').replace('-', '')
+
+        super(ZAIDField, self).clean(value)
+
+        if value in EMPTY_VALUES:
+            return u''
+
+        match = re.match(id_re, value)
+
+        if not match:
+            raise ValidationError(self.error_messages['invalid'])
+
+        g = match.groupdict()
+
+        try:
+            # The year 2000 is conveniently a leapyear.
+            # This algorithm will break in xx00 years which aren't leap years
+            # There is no way to guess the century of a ZA ID number
+            d = date(int(g['yy']) + 2000, int(g['mm']), int(g['dd']))
+        except ValueError:
+            raise ValidationError(self.error_messages['invalid'])
+
+        if not luhn(value):
+            raise ValidationError(self.error_messages['invalid'])
+
+        return value
+
+class ZAPostCodeField(RegexField):
+    default_error_messages = {
+        'invalid': _(u'Enter a valid South African postal code'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(ZAPostCodeField, self).__init__(r'^\d{4}$',
+            max_length=None, min_length=None)