2 files changed, 68 insertions, 0 deletions
diff --git a/stdnum/cy/__init__.py b/stdnum/cy/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/stdnum/cy/__init__.py
diff --git a/stdnum/cy/vat.py b/stdnum/cy/vat.py
new file mode 100644
index 0000000..b38a18f
--- /dev/null
+++ b/stdnum/cy/vat.py
@@ -0,0 +1,68 @@
+# vat.py - functions for handling Cypriot VAT numbers
+# coding: utf-8
+#
+# Copyright (C) 2012 Arthur de Jong
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301 USA
+
+"""Module for handling Cypriot Αριθμός Εγγραφής Φ.Π.Α. (VAT) numbers.
+
+The number consists of 9 digits where the last one is a is a letter and
+functions as a check digit.
+
+>>> compact('CY-10259033P')
+'10259033P'
+>>> is_valid('CY-10259033P ')
+True
+>>> is_valid('CY-10259033Z')  # invalid check digit
+False
+"""
+
+from stdnum.util import clean
+
+
+def compact(number):
+    """Convert the number to the minimal representation. This strips the
+    number of any valid separators and removes surrounding whitespace."""
+    number = clean(number, ' -').upper().strip()
+    if number.startswith('CY'):
+        number = number[2:]
+    return number
+
+
+def calc_check_digit(number):
+    """Calculate the check digit. The number passed should not have the
+    check digit included."""
+    translation = {
+        '0': 1, '1': 0, '2': 5, '3': 7, '4': 9,
+        '5': 13, '6': 15, '7': 17, '8': 19, '9': 21,
+    }
+    return 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'[(
+        sum(translation[x] for x in number[::2]) +
+        sum(int(x) for x in number[1::2])
+    ) % 26]
+
+
+def is_valid(number):
+    """Checks to see if the number provided is a valid VAT number. This
+    checks the length, formatting and check digit."""
+    try:
+        number = compact(number)
+    except:
+        return False
+    return len(number) == 9 and number[:-1].isdigit() and \
+           number[0:2] != '12' and \
+           number[-1] == calc_check_digit(number[:-1])