From c4ad09983a812210b4e42547c83da673ca843684 Mon Sep 17 00:00:00 2001
From: Arthur de Jong <arthur@arthurdejong.org>
Date: Tue, 20 Sep 2011 20:52:03 +0000
Subject: fix a problem with an ISBN13 with a valid check digit but with an
 unknown bookland prefix

git-svn-id: http://arthurdejong.org/svn/python-stdnum/python-stdnum@78 9dea7c4f-944c-4273-ac1a-574ede026edc
---
 stdnum/isbn.py          | 15 +++++++--------
 tests/test_isbn.doctest |  2 ++
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/stdnum/isbn.py b/stdnum/isbn.py
index d2fbe4d..382b13d 100644
--- a/stdnum/isbn.py
+++ b/stdnum/isbn.py
@@ -120,19 +120,18 @@ def split(number, convert=False):
     # clean up number
     number = compact(number, convert)
     # get Bookland prefix if any
+    delprefix = False
     if len(number) == 10:
-        oprefix = ''
-        prefix = '978'
-    else:
-        oprefix = prefix = number[:3]
-        number = number[3:]
+        number = '978' + number
+        delprefix = True
     # split the number
-    result = numdb.get('isbn').split(prefix + number[:-1])[1:]
-    itemnr = result.pop()
+    result = numdb.get('isbn').split(number[:-1])
+    itemnr = result.pop() if result else ''
+    prefix = result.pop(0) if result else ''
     group = result.pop(0) if result else ''
     publisher = result.pop(0) if result else ''
     # return results
-    return (oprefix, group, publisher, itemnr, number[-1])
+    return ('' if delprefix else prefix, group, publisher, itemnr, number[-1])
 
 
 def format(number, separator='-', convert=False):
diff --git a/tests/test_isbn.doctest b/tests/test_isbn.doctest
index 84143ec..a14a15d 100644
--- a/tests/test_isbn.doctest
+++ b/tests/test_isbn.doctest
@@ -59,3 +59,5 @@ Regrouping tests.
 ('', '99996', '', '7827', '0')
 >>> isbn.split('979-20-1234567-8')
 ('979', '', '', '201234567', '8')
+>>> isbn.split('5413170121522')  # valid checkdigit, unknown prefix
+('', '', '', '541317012152', '2')
-- 
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