From 5fe18d0ffaa6017b41e5ff638eb63997eecac4a1 Mon Sep 17 00:00:00 2001
From: Robin Stuart <robin@zint.org.uk>
Date: Mon, 9 May 2011 09:02:01 +0100
Subject: [PATCH] Correct ISBN13 check digit
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ISBN-13 check digit now correctly identifies '0'.
Thanks to Kévin Sailly.
---
 backend/upcean.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/backend/upcean.c b/backend/upcean.c
index da12c8f2..516aa954 100644
--- a/backend/upcean.c
+++ b/backend/upcean.c
@@ -378,6 +378,7 @@ char isbn13_check(unsigned char source[]) /* For ISBN(13) only */
 
 	check = sum % 10;
 	check = 10 - check;
+	if(check == 10) check = 0;
 	return itoc(check);
 }