From 9d607478438596365100e0f2aaf8138ce17deb99 Mon Sep 17 00:00:00 2001
From: Dmitry Gladkov <dmitry.gladkov@intel.com>
Date: Mon, 10 Sep 2018 13:49:50 +0300
Subject: [PATCH] common/rbtree: Add tree traversal and get root routines

The commit adds two routines:
- tree traversal that applies user-provided handler function for each node
- get root of a tree

The routines will be used in the further commits

Signed-off-by: Dmitry Gladkov <dmitry.gladkov@intel.com>
---
 include/rbtree.h |  7 +++++++
 src/rbtree.c     | 21 +++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/rbtree.h b/include/rbtree.h
index 34ff3dbe883..a0434b71752 100644
--- a/include/rbtree.h
+++ b/include/rbtree.h
@@ -95,5 +95,12 @@ RbtIterator rbtFindLeftmost(RbtHandle h, void *key,
 RbtIterator rbtFind(RbtHandle h, void *key);
 // returns iterator associated with key
 
+void rbtTraversal(RbtHandle h, RbtIterator it, void *handler_arg,
+          void(*handler)(void *arg, RbtIterator it));
+// tree traversal that visits (applies handler()) each node in the tree data
+//   strucutre exactly once.
+
+void *rbtRoot(RbtHandle h);
+// returns the root of the tree
 
 #endif /* RBTREE_H_ */
diff --git a/src/rbtree.c b/src/rbtree.c
index 6b88fb87940..c6377fa7c18 100644
--- a/src/rbtree.c
+++ b/src/rbtree.c
@@ -434,3 +434,24 @@ void *rbtFind(RbtHandle h, void *key) {
     }
     return NULL;
 }
+
+void rbtTraversal(RbtHandle h, RbtIterator it, void *handler_arg,
+          void(*handler)(void *arg, RbtIterator it)) {
+    RbtType *rbt = h;
+    NodeType *root = it;
+
+    // apply handler for:
+    // -o the root of the tree/subtree
+    handler(handler_arg, it);
+    // - the left subtree
+    if (root->left != SENTINEL)
+        rbtTraversal(h, root->left, handler_arg, handler);
+    // - the right subtree
+    if (root->right != SENTINEL)
+        rbtTraversal(h, root->right, handler_arg, handler);
+}
+
+void *rbtRoot(RbtHandle h) {
+    RbtType *rbt = h;
+    return rbt->root;
+}