From: Alex Ionescu
Date: Tue, 8 Nov 2005 23:40:37 +0000 (+0000)
Subject: - Implement Case 3 of RtlSplay
X-Git-Tag: backups/ros-branch-0_2_9@19949~826
X-Git-Url: https://git.reactos.org/?p=reactos.git;a=commitdiff_plain;h=98858edeba866aa2d009cd972d6af2fd5b5abd3b;hp=5c276df415a52de048e961994fe7a210f3312b09
- Implement Case 3 of RtlSplay
svn path=/trunk/; revision=19074
---
diff --git a/reactos/lib/rtl/splaytree.c b/reactos/lib/rtl/splaytree.c
index 50d28a56f54..ecce34ffbff 100644
--- a/reactos/lib/rtl/splaytree.c
+++ b/reactos/lib/rtl/splaytree.c
@@ -136,7 +136,7 @@ RtlSplay(PRTL_SPLAY_LINKS Links)
/*
* If they exist, update their parent pointers too,
- * since they've changed trees
+ * since they've changed trees.
*/
if (RtlLeftChild(P)) RtlParent(RtlLeftChild(P)) = P;
if (RtlLeftChild(G)) RtlParent(RtlLeftChild(G)) = G;
@@ -177,18 +177,74 @@ RtlSplay(PRTL_SPLAY_LINKS Links)
}
}
- /* Now N is on top, so P has become its child */
+ /* Now N is on top, so P has become its child. */
RtlRightChild(N) = P;
RtlParent(P) = N;
- /* N is on top, P is its child, so G is grandchild */
+ /* N is on top, P is its child, so G is grandchild. */
RtlRightChild(P) = G;
RtlParent(G) = P;
}
/* Case 3: P is the right child of G */
else if (RtlIsRightChild(P))
{
+ /*
+ * N's left-child becomes G's right child and
+ * N's right-child becomes P's left child.
+ */
+ RtlRightChild(G) = RtlLeftChild(N);
+ RtlLeftChild(P) = RtlRightChild(N);
+
+ /*
+ * If they exist, update their parent pointers too,
+ * since they've changed trees.
+ */
+ if (RtlRightChild(G)) RtlParent(RtlRightChild(G)) = G;
+ if (RtlLeftChild(P)) RtlParent(RtlLeftChild(P)) = P;
+
+ /*
+ * Now we'll shove N all the way to the top.
+ * Check if G is the root first.
+ */
+ if (RtlIsRoot(G))
+ {
+ /* G doesn't have a parent, so N will become the root! */
+ RtlParent(N) = N;
+ }
+ else
+ {
+ /* G has a parent, so inherit it since we take G's place */
+ RtlParent(N) = RtlParent(G);
+ /*
+ * Now find out who was referencing G and have it reference
+ * N instead, since we're taking G's place.
+ */
+ if (RtlIsLeftChild(G))
+ {
+ /*
+ * G was a left child, so change its parent's left
+ * child link to point to N now.
+ */
+ RtlLeftChild(RtlParent(G)) = N;
+ }
+ else
+ {
+ /*
+ * G was a right child, so change its parent's right
+ * child link to point to N now.
+ */
+ RtlLeftChild(RtlParent(G)) = N;
+ }
+ }
+
+ /* Now N is on top, so G has become its left child. */
+ RtlLeftChild(N) = G;
+ RtlParent(G) = N;
+
+ /* N is on top, G is its left child, so P is right child. */
+ RtlRightChild(N) = P;
+ RtlParent(P) = N;
}
/* "Finally" case: N doesn't have a grandparent => P is root */
else