Switch to python3

Shared/lib/python3.4/site-packages/stdnum/ean.py

@@ -0,0 +1,69 @@
+# ean.py - functions for handling EANs
+#
+# Copyright (C) 2011, 2012, 2013 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
+
+"""EAN (International Article Number).
+
+Module for handling EAN (International Article Number) codes. This
+module handles numbers EAN-13, EAN-8 and UPC (12-digit) format.
+
+>>> validate('73513537')
+'73513537'
+>>> validate('978-0-471-11709-4') # EAN-13 format
+'9780471117094'
+"""
+
+from stdnum.exceptions import *
+from stdnum.util import clean
+
+
+def compact(number):
+    """Convert the EAN to the minimal representation. This strips the number
+    of any valid separators and removes surrounding whitespace."""
+    return clean(number, ' -').strip()
+
+
+def calc_check_digit(number):
+    """Calculate the EAN check digit for 13-digit numbers. The number passed
+    should not have the check bit included."""
+    return str((10 - sum((3 - 2 * (i % 2)) * int(n)
+                         for i, n in enumerate(reversed(number)))) % 10)
+
+
+def validate(number):
+    """Checks to see if the number provided is a valid EAN-13. This checks
+    the length and the check bit but does not check whether a known GS1
+    Prefix and company identifier are referenced."""
+    number = compact(number)
+    if not number.isdigit():
+        raise InvalidFormat()
+    if len(number) not in (13, 12, 8):
+        raise InvalidLength()
+    if calc_check_digit(number[:-1]) != number[-1]:
+        raise InvalidChecksum()
+    return number
+
+
+def is_valid(number):
+    """Checks to see if the number provided is a valid EAN-13. This checks
+    the length and the check bit but does not check whether a known GS1
+    Prefix and company identifier are referenced."""
+    try:
+        return bool(validate(number))
+    except ValidationError:
+        return False