From d13b4a793d577be2364bcabb05bca1f19321b65a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= <p@janouch.name>
Date: Sat, 24 Sep 2022 18:42:59 +0200
Subject: [PATCH] Prevent undefined behaviour

---
 src/stardict.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/stardict.c b/src/stardict.c
index cdd11a1..6775553 100644
--- a/src/stardict.c
+++ b/src/stardict.c
@@ -1014,6 +1014,10 @@ stardict_longest_common_collation_prefix (StardictDict *sd,
 	u_strFromUTF8 (NULL, 0, &uc2_len, s2, -1, &error);
 	error = U_ZERO_ERROR;
 
+	// Prevent undefined behaviour with VLAs.
+	if (!uc1_len || !uc2_len)
+		return 0;
+
 	UChar uc1[uc1_len];
 	UChar uc2[uc2_len];
 	u_strFromUTF8 (uc1, uc1_len, NULL, s1, -1, &error);