+// below are functions by (C) Costa Tsaousis
+
+// ---------------------------
+// traversing
+
+int avl_walker(avl *node, int (*callback)(void *entry, void *data), void *data) {
+ int total = 0, ret = 0;
+
+ if(node->avl_link[0]) {
+ ret = avl_walker(node->avl_link[0], callback, data);
+ if(ret < 0) return ret;
+ total += ret;
+ }
+
+ ret = callback(node, data);
+ if(ret < 0) return ret;
+ total += ret;
+
+ if(node->avl_link[1]) {
+ ret = avl_walker(node->avl_link[1], callback, data);
+ if (ret < 0) return ret;
+ total += ret;
+ }
+
+ return total;
+}
+
+int avl_traverse(avl_tree *t, int (*callback)(void *entry, void *data), void *data) {
+ return avl_walker(t->root, callback, data);
+}
+
+// ---------------------------
+// locks