util: Fix GSM to UTF8 conversion mechanism

diff --git a/src/util.c b/src/util.c
index aecc790..41ef3d4 100644 (file)
--- a/src/util.c
+++ b/src/util.c
@@ -628,8 +628,16 @@ char *convert_gsm_to_utf8_with_lang(const unsigned char *text, long len,
 
                        c = gsm_single_shift_lookup(&t, text[i]);
 
+                       /*
+                        * According to the 3GPP specifications 23.038
+                        * section 6.2.1.1:
+                        * In the case there is no character in the extension
+                        * table, the character of the main default alphabet
+                        * table or the character from the National Language
+                        * Locking Shift Table should be displayed.
+                        */
                        if (c == GUND)
-                               goto error;
+                               c = gsm_locking_shift_lookup(&t, text[i]);
                } else {
                        c = gsm_locking_shift_lookup(&t, text[i]);
                }
@@ -647,9 +655,12 @@ char *convert_gsm_to_utf8_with_lang(const unsigned char *text, long len,
        while (out < res + res_length) {
                unsigned short c;
 
-               if (text[i] == 0x1b)
+               if (text[i] == 0x1b) {
                        c = gsm_single_shift_lookup(&t, text[++i]);
-               else
+                       /* See 3GPP 23.038 section 6.2.1.1 */
+                       if (c == GUND)
+                               c = gsm_locking_shift_lookup(&t, text[i]);
+               } else
                        c = gsm_locking_shift_lookup(&t, text[i]);
 
                out += g_unichar_to_utf8(c, out);