Fix calculation of ISMN check digit.

This has always been broken, so back-patch to all supported versions.

Fabien COELHO

diff --git a/contrib/isn/isn.c b/contrib/isn/isn.c
index dac760b1114846fbdc513f6effe1bf0792ccf839..6527b4b3af63ef7e18e38443f24012328cfeae11 100644 (file)
--- a/contrib/isn/isn.c
+++ b/contrib/isn/isn.c
@@ -822,7 +822,7 @@ string2ean(const char *str, bool errorOK, ean13 *result,
        case ISMN:
            strncpy(buf, "9790", 4);    /* this isn't for sure yet, for now
                                         * ISMN it's only 9790 */
-           valid = (valid && ((rcheck = checkdig(buf + 3, 10)) == check || magic));
+           valid = (valid && ((rcheck = checkdig(buf, 13)) == check || magic));
            break;
        case ISBN:
            strncpy(buf, "978", 3);