[MERGE] base_vat: support for Norwegian VAT codes, courtesy of Rolv Råen (adEgo)

bzr revid: odo@openerp.com-20110915101130-51jabei9e5tspj6r

addons/base_vat/base_vat.py

@@ -42,7 +42,7 @@ _ref_vat = {
     'pt': 'PT123456789', 'ro': 'RO1234567897',
     'se': 'SE123456789701', 'si': 'SI12345679',
     'sk': 'SK0012345675', 'el': 'EL12345670',
-    'mx': 'MXABCD831230T1B',
+    'mx': 'MXABC123456T1B', 'no': 'NO123456785'
 
             }
 
@@ -1104,7 +1104,33 @@ class res_partner(osv.osv):
         
         #Valid format and valid date
         return True
-        
+
+
+    # check_vat_no contributed by Rolv Råen (adEgo)
+    def check_vat_no(self, vat):
+        '''
+        Check Norway VAT number.See http://www.brreg.no/english/coordination/number.html
+        '''
+        if len(vat) != 9:
+            return False
+        try:
+            int(vat)
+        except ValueError:
+            return False
+
+        sum = (3 * int(vat[0])) + (2 * int(vat[1])) + \
+            (7 * int(vat[2])) + (6 * int(vat[3])) + \
+            (5 * int(vat[4])) + (4 * int(vat[5])) + \
+            (3 * int(vat[6])) + (2 * int(vat[7]))
+
+        check = 11 -(sum % 11)
+        if check == 11:
+            check = 0
+        if check == 10:
+            # 10 is not a valid check digit for an organization number
+            return False
+        return check == int(vat[8])
+
 res_partner()
 
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