Don't walk over empty trees

diff --git a/src/lib/rbtree.c b/src/lib/rbtree.c
index 365423c..3a5a7ca 100644 (file)
--- a/src/lib/rbtree.c
+++ b/src/lib/rbtree.c
@@ -587,6 +587,8 @@ static int WalkNodePostOrder(rbnode_t *X,
 int rbtree_walk(rbtree_t *tree, RBTREE_ORDER order,
                int (*callback)(void *, void *), void *context)
 {
+       if (tree->Root == NIL) return 0;
+
        switch (order) {
        case PreOrder:
                return WalkNodePreOrder(tree->Root, callback, context);