From: Sebastian Harl <sh@tokkee.org>
Date: Fri, 11 Jul 2014 15:42:33 +0000 (+0200)
Subject: avltree: Iterate through the tree depth-first when clearing it.
X-Git-Tag: sysdb-0.3.0~57
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=be24944a8a24aca28b54dafb6a1385507e5ca67c;p=sysdb.git

avltree: Iterate through the tree depth-first when clearing it.

Else, we cannot simple delete each node but we'd have to actually remove it
from the tree because we'd be removing non-leaf nodes.

Don't use recursion for iterating the tree. It's not needed and would
consume stack-space unnecessarily. The current approach limits the size of the
tree by heap memory only.
---

diff --git a/src/utils/avltree.c b/src/utils/avltree.c
index 7397a34..aad2b9a 100644
--- a/src/utils/avltree.c
+++ b/src/utils/avltree.c
@@ -154,9 +154,30 @@ tree_clear(sdb_avltree_t *tree)
 {
 	node_t *n;
 
-	n = node_smallest(tree);
+	if ((! tree) || (! tree->root))
+		return;
+
+	/* do a depth-first iteration and delete the leafs */
+	n = tree->root;
 	while (n) {
-		node_t *tmp = node_next(n);
+		node_t *tmp;
+
+		if (n->left) {
+			n = n->left;
+			continue;
+		}
+		else if (n->right) {
+			n = n->right;
+			continue;
+		}
+
+		tmp = n->parent;
+		if (tmp) {
+			if (tmp->left == n)
+				tmp->left = NULL;
+			else
+				tmp->right = NULL;
+		}
 
 		node_destroy(n);
 		n = tmp;