From 740fdbcd0e6d25c1d6f12537ca2aa559650b9d52 Mon Sep 17 00:00:00 2001
From: jfkthame <jfkthame@gmail.com>
Date: Mon, 3 Apr 2017 12:22:39 +0100
Subject: [PATCH] avoid UBSan warning in get_stage_lookups (#450)

See https://bugzilla.mozilla.org/show_bug.cgi?id=1336600
---
 src/hb-ot-map-private.hh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/hb-ot-map-private.hh b/src/hb-ot-map-private.hh
index 0395c9c22..b69e5344c 100644
--- a/src/hb-ot-map-private.hh
+++ b/src/hb-ot-map-private.hh
@@ -113,7 +113,7 @@ struct hb_ot_map_t
     assert (stage <= stages[table_index].len);
     unsigned int start = stage ? stages[table_index][stage - 1].last_lookup : 0;
     unsigned int end   = stage < stages[table_index].len ? stages[table_index][stage].last_lookup : lookups[table_index].len;
-    *plookups = &lookups[table_index][start];
+    *plookups = end == start ? NULL : &lookups[table_index][start];
     *lookup_count = end - start;
   }