rbtree: API changes. Remove rbtree control node from RBTree_Next.

The implementation of RBTree_Next was using an awkward construction to detect
and avoid accessing the false root of the red-black tree. To deal with the
false root, RBTree_Next was comparing node parents with the control node.
Instead the false root can be detected by checking if the grandparent of a
node exists; the grandparent of the tree's true root is NULL by definition
so the root of the tree is found while walking up the tree by checking for
the non-existence of a grandparent.

This change propagates into the predecessor/successor and iterate functions.

1 files changed, 2 insertions, 2 deletions

diff --git a/cpukit/score/src/rbtreeextract.c b/cpukit/score/src/rbtreeextract.c
index 9a0a18bea8..e3b27fc430 100644
--- a/cpukit/score/src/rbtreeextract.c
+++ b/cpukit/score/src/rbtreeextract.c
@@ -109,7 +109,7 @@ void _RBTree_Extract_unprotected(
   /* check if min needs to be updated */
   if (the_node == the_rbtree->first[RBT_LEFT]) {
     RBTree_Node *next;
-    next = _RBTree_Successor_unprotected(the_rbtree, the_node);
+    next = _RBTree_Successor_unprotected(the_node);
     the_rbtree->first[RBT_LEFT] = next;
   }
 
@@ -117,7 +117,7 @@ void _RBTree_Extract_unprotected(
    * do not use else if here. */
   if (the_node == the_rbtree->first[RBT_RIGHT]) {
     RBTree_Node *previous;
-    previous = _RBTree_Predecessor_unprotected(the_rbtree, the_node);
+    previous = _RBTree_Predecessor_unprotected(the_node);
     the_rbtree->first[RBT_RIGHT] = previous;
   }