From 26c8cbc9315974aaadd997d9cf869cb43f5e33d8 Mon Sep 17 00:00:00 2001
From: Pasi Kallinen <paxed@alt.org>
Date: Fri, 26 Apr 2024 07:59:42 +0300
Subject: [PATCH] Fix drawbridge checking outside map

---
 src/dbridge.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/dbridge.c b/src/dbridge.c
index f5ee2403e..72c73cb93 100644
--- a/src/dbridge.c
+++ b/src/dbridge.c
@@ -131,28 +131,30 @@ db_under_typ(int mask)
  * We want to know whether a wall (or a door) is the portcullis (passageway)
  * of an eventual drawbridge.
  *
- * Return value:  the direction of the drawbridge.
+ * Return value:  the direction of the drawbridge, or -1 if not valid
  */
-
 int
 is_drawbridge_wall(coordxy x, coordxy y)
 {
     struct rm *lev;
 
+    if (!isok(x, y))
+        return -1;
+
     lev = &levl[x][y];
     if (lev->typ != DOOR && lev->typ != DBWALL)
         return -1;
 
-    if (IS_DRAWBRIDGE(levl[x + 1][y].typ)
+    if (isok(x + 1, y) && IS_DRAWBRIDGE(levl[x + 1][y].typ)
         && (levl[x + 1][y].drawbridgemask & DB_DIR) == DB_WEST)
         return DB_WEST;
-    if (IS_DRAWBRIDGE(levl[x - 1][y].typ)
+    if (isok(x - 1, y) && IS_DRAWBRIDGE(levl[x - 1][y].typ)
         && (levl[x - 1][y].drawbridgemask & DB_DIR) == DB_EAST)
         return DB_EAST;
-    if (IS_DRAWBRIDGE(levl[x][y - 1].typ)
+    if (isok(x, y - 1) && IS_DRAWBRIDGE(levl[x][y - 1].typ)
         && (levl[x][y - 1].drawbridgemask & DB_DIR) == DB_SOUTH)
         return DB_SOUTH;
-    if (IS_DRAWBRIDGE(levl[x][y + 1].typ)
+    if (isok(x, y + 1) && IS_DRAWBRIDGE(levl[x][y + 1].typ)
         && (levl[x][y + 1].drawbridgemask & DB_DIR) == DB_NORTH)
         return DB_NORTH;