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- Implement Case 1 of RtlSplay

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svn path=/trunk/; revision=19073
This commit is contained in:
Alex Ionescu 2005-11-08 23:33:07 +00:00
parent 3d244e2b37
commit 5c276df415
1 changed files with 56 additions and 0 deletions
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56
reactos/lib/rtl/splaytree.c
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@ -127,7 +127,63 @@ RtlSplay(PRTL_SPLAY_LINKS Links)
/* Case 1: P is the left child of G */
if (RtlIsLeftChild(P))
{
/*
* N's right-child becomes P's left child and
* P's right-child becomes G's left child.
*/
RtlLeftChild(P) = RtlRightChild(N);
RtlLeftChild(G) = RtlRightChild(P);
/*
* If they exist, update their parent pointers too,
* since they've changed trees
*/
if (RtlLeftChild(P)) RtlParent(RtlLeftChild(P)) = P;
if (RtlLeftChild(G)) RtlParent(RtlLeftChild(G)) = G;
/*
* 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 P has become its child */
RtlRightChild(N) = P;
RtlParent(P) = N;
/* 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))