From f6309cbf8058b77729f9ba96c26accdbb7ae5596 Mon Sep 17 00:00:00 2001
From: Malcolm Tredinnick <malcolm.tredinnick@gmail.com>
Date: Fri, 10 Apr 2009 01:03:44 +0000
Subject: [PATCH] Fixed #8515 -- Fixed validation of Polish REGON numbers.

Patch from Piotr Lewandowski.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10460 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/contrib/localflavor/pl/forms.py        | 39 ++++++++-----------
 tests/regressiontests/forms/localflavor/pl.py | 12 +++++-
 2 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/django/contrib/localflavor/pl/forms.py b/django/contrib/localflavor/pl/forms.py
index ee362fcd6d..b908580568 100644
--- a/django/contrib/localflavor/pl/forms.py
+++ b/django/contrib/localflavor/pl/forms.py
@@ -100,20 +100,18 @@ class PLNIPField(RegexField):
 
 class PLREGONField(RegexField):
     """
-    A form field that validated as Polish National Official Business Register
-    Number (REGON). Valid numbers contain 7 or 9 digits.
+    A form field that validates its input is a REGON number.
 
-    More on the field: http://www.stat.gov.pl/bip/regon_ENG_HTML.htm
-
-    The checksum algorithm is documented at http://wipos.p.lodz.pl/zylla/ut/nip-rego.html
+    Valid regon number consists of 9 or 14 digits.
+    See http://www.stat.gov.pl/bip/regon_ENG_HTML.htm for more information.
     """
     default_error_messages = {
-        'invalid': _(u'National Business Register Number (REGON) consists of 7 or 9 digits.'),
+        'invalid': _(u'National Business Register Number (REGON) consists of 9 or 14 digits.'),
         'checksum': _(u'Wrong checksum for the National Business Register Number (REGON).'),
     }
 
     def __init__(self, *args, **kwargs):
-        super(PLREGONField, self).__init__(r'^\d{7,9}$',
+        super(PLREGONField, self).__init__(r'^\d{9,14}$',
             max_length=None, min_length=None, *args, **kwargs)
 
     def clean(self,value):
@@ -126,25 +124,20 @@ class PLREGONField(RegexField):
         """
         Calculates a checksum with the provided algorithm.
         """
-        multiple_table_7 = (2, 3, 4, 5, 6, 7)
-        multiple_table_9 = (8, 9, 2, 3, 4, 5, 6, 7)
-        result = 0
+        weights = (
+            (8, 9, 2, 3, 4, 5, 6, 7, -1),
+            (2, 4, 8, 5, 0, 9, 7, 3, 6, 1, 2, 4, 8, -1),
+            (8, 9, 2, 3, 4, 5, 6, 7, -1, 0, 0, 0, 0, 0),
+        )
 
-        if len(number) == 7:
-            multiple_table = multiple_table_7
-        else:
-            multiple_table = multiple_table_9
+        weights = [table for table in weights if len(table) == len(number)]
 
-        for i in range(len(number)-1):
-            result += int(number[i]) * multiple_table[i]
+        for table in weights:
+            checksum = sum([int(n) * w for n, w in zip(number, table)])
+            if checksum % 11 % 10:
+                return False
 
-        result %= 11
-        if result == 10:
-            result = 0
-        if result  == int(number[-1]):
-            return True
-        else:
-            return False
+        return bool(weights)
 
 class PLPostalCodeField(RegexField):
     """
diff --git a/tests/regressiontests/forms/localflavor/pl.py b/tests/regressiontests/forms/localflavor/pl.py
index ce6ccda81a..52f1305ca8 100644
--- a/tests/regressiontests/forms/localflavor/pl.py
+++ b/tests/regressiontests/forms/localflavor/pl.py
@@ -67,8 +67,18 @@ ValidationError: [u'National Identification Number consists of 11 digits.']
 
 >>> from django.contrib.localflavor.pl.forms import PLREGONField
 >>> f = PLREGONField()
+>>> f.clean('12345678512347')
+u'12345678512347'
 >>> f.clean('590096454')
 u'590096454'
+>>> f.clean('123456784')
+Traceback (most recent call last):
+...
+ValidationError: [u'Wrong checksum for the National Business Register Number (REGON).']
+>>> f.clean('12345678412342')
+Traceback (most recent call last):
+...
+ValidationError: [u'Wrong checksum for the National Business Register Number (REGON).']
 >>> f.clean('590096453')
 Traceback (most recent call last):
 ...
@@ -76,6 +86,6 @@ ValidationError: [u'Wrong checksum for the National Business Register Number (RE
 >>> f.clean('590096')
 Traceback (most recent call last):
 ...
-ValidationError: [u'National Business Register Number (REGON) consists of 7 or 9 digits.']
+ValidationError: [u'National Business Register Number (REGON) consists of 9 or 14 digits.']
 
 """