From: north <devnull@localhost>
Date: Mon, 20 Oct 2008 14:49:07 +0000 (+0000)
Subject: Attempted fix to bug 1485, agedge has memory access violation
X-Git-Tag: LAST_LIBGRAPH~32^2~3065
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bee3de5a73fac8819834a9ece3767a9c07f0fc02;p=graphviz

Attempted fix to bug 1485, agedge has memory access violation
when search for an edge that does not exist in a subgraph.
---

diff --git a/lib/cgraph/edge.c b/lib/cgraph/edge.c
index 756f25eac..22bb3bd3b 100644
--- a/lib/cgraph/edge.c
+++ b/lib/cgraph/edge.c
@@ -111,14 +111,17 @@ static Agedge_t *agfindedge_by_key(Agraph_t * g, Agnode_t * t, Agnode_t * h,
     template.base.tag = key;
     template.node = t;		/* guess that fan-in < fan-out */
     sn = agsubrep(g, h);
-    if (t != h) {
-	dtrestore(g->e_id, sn->in_id);
-	e = (Agedge_t *) dtsearch(g->e_id, &template);
-	sn->in_id = dtextract(g->e_id);
-    } else {			/* self edge */
-	dtrestore(g->e_id, sn->out_id);
-	e = (Agedge_t *) dtsearch(g->e_id, &template);
-	sn->out_id = dtextract(g->e_id);
+    if (!sn) e = 0;
+    else {
+	if (t != h) {
+	    dtrestore(g->e_id, sn->in_id);
+	    e = (Agedge_t *) dtsearch(g->e_id, &template);
+	    sn->in_id = dtextract(g->e_id);
+	} else {			/* self edge */
+	    dtrestore(g->e_id, sn->out_id);
+	    e = (Agedge_t *) dtsearch(g->e_id, &template);
+	    sn->out_id = dtextract(g->e_id);
+	}
     }
     return e;
 }