/*
* @implemented
*/
PRTL_SPLAY_LINKS
NTAPI
RtlRealSuccessor(PRTL_SPLAY_LINKS Links)
{
PRTL_SPLAY_LINKS Child;
/* Get the right child */
Child = RtlRightChild(Links);
if (Child)
{
/* Get left-most child */
while (RtlLeftChild(Child)) Child = RtlLeftChild(Child);
return Child;
}
/* We don't have a right child, keep looping until we find our parent */
Child = Links;
while (RtlIsRightChild(Child)) Child = RtlParent(Child);
/* The parent should be a left child, return the real successor */
if (RtlIsLeftChild(Child)) return RtlParent(Child);
/* The parent isn't a right child, so no real successor for us */
return NULL;
}
PRTL_SPLAY_LINKS
RtlRealPredecessor (
IN PRTL_SPLAY_LINKS Links
)
/*++
Routine Description:
The RealPredecessor function takes as input a pointer to a splay link
in a tree and returns a pointer to the predecessor of the input node
within the entire tree. If there is not a predecessor, the return value
is NULL.
Arguments:
Links - Supplies a pointer to a splay link in a tree.
Return Value:
PRTL_SPLAY_LINKS - returns a pointer to the predecessor in the entire tree
--*/
{
PRTL_SPLAY_LINKS Ptr;
/*
first check to see if there is a left subtree to the input link
if there is then the real predecessor is the right most node in
the left subtree. That is find and return P in the following diagram
Links
/
.
.
.
P
/
*/
if ((Ptr = RtlLeftChild(Links)) != NULL) {
while (RtlRightChild(Ptr) != NULL) {
Ptr = RtlRightChild(Ptr);
}
return Ptr;
}
/*
we do not have a left child so check to see if have a parent and if
so find the first ancestor that we are a right descendent of. That
is find and return P in the following diagram
P
\
.
.
.
Links
*/
Ptr = Links;
while (RtlIsLeftChild(Ptr)) {
Ptr = RtlParent(Ptr);
}
if (RtlIsRightChild(Ptr)) {
return RtlParent(Ptr);
}
//
// otherwise we are do not have a real predecessor so we simply return
// NULL
//
return NULL;
}
PRTL_SPLAY_LINKS
RtlSplay (
IN PRTL_SPLAY_LINKS Links
)
/*++
Routine Description:
The Splay function takes as input a pointer to a splay link in a tree
and splays the tree. Its function return value is a pointer to the
root of the splayed tree.
Arguments:
Links - Supplies a pointer to a splay link in a tree.
Return Value:
PRTL_SPLAY_LINKS - returns a pointer to the root of the splayed tree.
--*/
{
PRTL_SPLAY_LINKS L;
PRTL_SPLAY_LINKS P;
PRTL_SPLAY_LINKS G;
//
// while links is not the root we need to keep rotating it toward
// the root
//
L = Links;
while (!RtlIsRoot(L)) {
P = RtlParent(L);
G = RtlParent(P);
if (RtlIsLeftChild(L)) {
if (RtlIsRoot(P)) {
/*
we have the following case
P L
/ \ / \
L c ==> a P
/ \ / \
a b b c
*/
//
// Connect P & b
//
P->LeftChild = L->RightChild;
if (P->LeftChild != NULL) {P->LeftChild->Parent = P;}
//
// Connect L & P
//
L->RightChild = P;
P->Parent = L;
//
// Make L the root
//
L->Parent = L;
} else if (RtlIsLeftChild(P)) {
/*
we have the following case
| |
G L
/ \ / \
P d ==> a P
/ \ / \
L c b G
/ \ / \
a b c d
*/
//
// Connect P & b
//
P->LeftChild = L->RightChild;
if (P->LeftChild != NULL) {P->LeftChild->Parent = P;}
//
// Connect G & c
//
G->LeftChild = P->RightChild;
if (G->LeftChild != NULL) {G->LeftChild->Parent = G;}
//
// Connect L & Great GrandParent
//
if (RtlIsRoot(G)) {
L->Parent = L;
} else {
L->Parent = G->Parent;
*(ParentsChildPointerAddress(G)) = L;
}
//
// Connect L & P
//
L->RightChild = P;
P->Parent = L;
//
// Connect P & G
//
P->RightChild = G;
G->Parent = P;
} else { // RtlIsRightChild(Parent)
/*
we have the following case
| |
G L
/ \ / \
a P G P
/ \ / \ / \
L d ==> a b c d
/ \
b c
*/
//
// Connect G & b
//
G->RightChild = L->LeftChild;
if (G->RightChild != NULL) {G->RightChild->Parent = G;}
//
// Connect P & c
//
P->LeftChild = L->RightChild;
if (P->LeftChild != NULL) {P->LeftChild->Parent = P;}
//
// Connect L & Great GrandParent
//
if (RtlIsRoot(G)) {
L->Parent = L;
} else {
L->Parent = G->Parent;
*(ParentsChildPointerAddress(G)) = L;
}
//
// Connect L & G
//
L->LeftChild = G;
G->Parent = L;
//
// Connect L & P
//
L->RightChild = P;
P->Parent = L;
}
} else { // RtlIsRightChild(L)
if (RtlIsRoot(P)) {
/*
we have the following case
P L
/ \ / \
a L P c
/ \ / \
b c ==> a b
*/
//
// Connect P & b
//
P->RightChild = L->LeftChild;
if (P->RightChild != NULL) {P->RightChild->Parent = P;}
//
// Connect P & L
//
L->LeftChild = P;
P->Parent = L;
//
// Make L the root
//
L->Parent = L;
} else if (RtlIsRightChild(P)) {
/*
we have the following case
| |
G L
/ \ / \
a P P d
/ \ / \
b L G c
/ \ / \
c d ==> a b
*/
//
// Connect G & b
//
G->RightChild = P->LeftChild;
if (G->RightChild != NULL) {G->RightChild->Parent = G;}
//
// Connect P & c
//
P->RightChild = L->LeftChild;
if (P->RightChild != NULL) {P->RightChild->Parent = P;}
//
// Connect L & Great GrandParent
//
if (RtlIsRoot(G)) {
L->Parent = L;
} else {
L->Parent = G->Parent;
*(ParentsChildPointerAddress(G)) = L;
}
//
// Connect L & P
//
L->LeftChild = P;
P->Parent = L;
//
// Connect P & G
//
P->LeftChild = G;
G->Parent = P;
} else { // RtlIsLeftChild(P)
/*
we have the following case
| |
G L
/ \ / \
P d P G
/ \ / \ / \
a L ==> a b c d
/ \
b c
*/
//
// Connect P & b
//
P->RightChild = L->LeftChild;
if (P->RightChild != NULL) {P->RightChild->Parent = P;}
//
// Connect G & c
//
G->LeftChild = L->RightChild;
if (G->LeftChild != NULL) {G->LeftChild->Parent = G;}
//
// Connect L & Great GrandParent
//
if (RtlIsRoot(G)) {
L->Parent = L;
} else {
L->Parent = G->Parent;
*(ParentsChildPointerAddress(G)) = L;
}
//
// Connect L & P
//
L->LeftChild = P;
P->Parent = L;
//
// Connect L & G
//
L->RightChild = G;
G->Parent = L;
}
}
}
return L;
}
/*
* @implemented
*/
VOID
NTAPI
RtlRemoveUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry)
{
PUNICODE_PREFIX_TABLE_ENTRY Entry, RefEntry, NewEntry;
PRTL_SPLAY_LINKS SplayLinks;
DPRINT("RtlRemoveUnicodePrefix(): Table %p, TableEntry %p\n",
PrefixTable, PrefixTableEntry);
/* Erase the last entry */
PrefixTable->LastNextEntry = NULL;
/* Check if this was a Case Match Entry */
if (PrefixTableEntry->NodeTypeCode == PFX_NTC_CASE_MATCH)
{
/* Get the case match entry */
Entry = PrefixTableEntry->CaseMatch;
/* Now loop until we find one referencing what the caller sent */
while (Entry->CaseMatch != PrefixTableEntry) Entry = Entry->CaseMatch;
/* We found the entry that was sent, link them to delete this entry */
Entry->CaseMatch = PrefixTableEntry->CaseMatch;
}
else if ((PrefixTableEntry->NodeTypeCode == PFX_NTC_ROOT) ||
(PrefixTableEntry->NodeTypeCode == PFX_NTC_CHILD))
{
/* Check if this entry is a case match */
if (PrefixTableEntry->CaseMatch != PrefixTableEntry)
{
/* Get the case match entry */
Entry = PrefixTableEntry->CaseMatch;
/* Now loop until we find one referencing what the caller sent */
while (Entry->CaseMatch != PrefixTableEntry) Entry = Entry->CaseMatch;
/* We found the entry that was sent, link them to delete this entry */
Entry->CaseMatch = PrefixTableEntry->CaseMatch;
/* Copy the data */
Entry->NodeTypeCode = PrefixTableEntry->NodeTypeCode;
Entry->NextPrefixTree = PrefixTableEntry->NextPrefixTree;
Entry->Links = PrefixTableEntry->Links;
/* Now check if we are a root entry */
if (RtlIsRoot(&PrefixTableEntry->Links))
{
/* We are, so make this entry root as well */
Entry->Links.Parent = &Entry->Links;
/* Find the entry referencing us */
RefEntry = Entry->NextPrefixTree;
while (RefEntry->NextPrefixTree != Entry)
{
/* Not this one, move to the next entry */
RefEntry = RefEntry->NextPrefixTree;
}
/* Link them to us now */
RefEntry->NextPrefixTree = Entry;
}
else if (RtlIsLeftChild(&PrefixTableEntry->Links))
{
/* We were the left child, so make us as well */
RtlParent(&PrefixTableEntry->Links)->LeftChild = &Entry->Links;
}
else
{
/* We were the right child, so make us as well */
RtlParent(&PrefixTableEntry->Links)->RightChild = &Entry->Links;
}
/* Check if we have a left child */
if (RtlLeftChild(&Entry->Links))
{
/* Update its parent link */
RtlLeftChild(&Entry->Links)->Parent = &Entry->Links;
}
/* Check if we have a right child */
if (RtlRightChild(&Entry->Links))
{
/* Update its parent link */
RtlRightChild(&Entry->Links)->Parent = &Entry->Links;
}
}
else
{
/* It's not a case match, so we'll delete the actual entry */
SplayLinks = &PrefixTableEntry->Links;
/* Find the root entry */
while (!RtlIsRoot(SplayLinks)) SplayLinks = RtlParent(SplayLinks);
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Delete the entry and check if the whole tree is gone */
SplayLinks = RtlDelete(&PrefixTableEntry->Links);
if (!SplayLinks)
{
/* The tree is also gone now, find the entry referencing us */
RefEntry = Entry->NextPrefixTree;
while (RefEntry->NextPrefixTree != Entry)
{
/* Not this one, move to the next entry */
RefEntry = RefEntry->NextPrefixTree;
}
/* Link them so this entry stops being referenced */
RefEntry->NextPrefixTree = Entry->NextPrefixTree;
}
else if (&Entry->Links != SplayLinks)
{
/* The tree is still here, but we got moved to a new one */
NewEntry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Find the entry referencing us */
RefEntry = Entry->NextPrefixTree;
while (RefEntry->NextPrefixTree != Entry)
{
/* Not this one, move to the next entry */
RefEntry = RefEntry->NextPrefixTree;
}
/* Since we got moved, make us the new root entry */
NewEntry->NodeTypeCode = PFX_NTC_ROOT;
/* Link us with the entry referencing the old root */
RefEntry->NextPrefixTree = NewEntry;
/* And link us with the old tree */
NewEntry->NextPrefixTree = Entry->NextPrefixTree;
/* Set the old tree as a child */
Entry->NodeTypeCode = PFX_NTC_CHILD;
Entry->NextPrefixTree = NULL;
}
}
}
}
VOID
FsRtlAddToTunnelCache (
IN PTUNNEL Cache,
IN ULONGLONG DirKey,
IN PUNICODE_STRING ShortName,
IN PUNICODE_STRING LongName,
IN BOOLEAN KeyByShortName,
IN ULONG DataLength,
IN PVOID Data
)
/*++
Routine Description:
Adds an entry to the tunnel cache keyed by
DirectoryKey ## (KeyByShortName ? ShortName : LongName)
ShortName, LongName, and Data are copied and stored in the tunnel. As a side
effect, if there are too many entries in the tunnel cache, this routine will
initiate expiration in the tunnel cache.
Arguments:
Cache - a tunnel cache initialized by FsRtlInitializeTunnelCache()
DirKey - the key value of the directory the name appeared in
ShortName - (optional if !KeyByShortName) the 8.3 name of the file
LongName - (optional if KeyByShortName) the long name of the file
KeyByShortName - specifies which name is keyed in the tunnel cache
DataLength - specifies the length of the opaque data segment (file
system specific) which contains the tunnelling information for this
file
Data - pointer to the opaque tunneling data segment
Return Value:
None
--*/
{
LONG Compare;
ULONG NodeSize;
PUNICODE_STRING NameKey;
PRTL_SPLAY_LINKS *Links;
LIST_ENTRY FreePoolList;
PTUNNEL_NODE Node = NULL;
PTUNNEL_NODE NewNode = NULL;
BOOLEAN FreeOldNode = FALSE;
BOOLEAN AllocatedFromPool = FALSE;
PAGED_CODE();
//
// If MaxEntries is 0 then tunneling is disabled.
//
if (TunnelMaxEntries == 0) return;
InitializeListHead(&FreePoolList);
//
// Grab a new node for this data
//
NodeSize = sizeof(TUNNEL_NODE) + ShortName->Length + LongName->Length + DataLength;
if (LOOKASIDE_NODE_SIZE >= NodeSize) {
NewNode = ExAllocateFromPagedLookasideList(&TunnelLookasideList);
}
if (NewNode == NULL) {
//
// Data doesn't fit in lookaside nodes
//
NewNode = ExAllocatePoolWithTag(PagedPool, NodeSize, 'PnuT');
if (NewNode == NULL) {
//
// Give up tunneling this entry
//
return;
}
AllocatedFromPool = TRUE;
}
//
// Traverse the cache to find our insertion point
//
NameKey = (KeyByShortName ? ShortName : LongName);
ExAcquireFastMutex(&Cache->Mutex);
Links = &Cache->Cache;
while (*Links) {
Node = CONTAINING_RECORD(*Links, TUNNEL_NODE, CacheLinks);
Compare = FsRtlCompareNodeAndKey(Node, DirKey, NameKey);
if (Compare > 0) {
Links = &RtlLeftChild(&Node->CacheLinks);
} else {
if (Compare < 0) {
Links = &RtlRightChild(&Node->CacheLinks);
} else {
break;
}
}
}
//
// Thread new data into the splay tree
//
RtlInitializeSplayLinks(&NewNode->CacheLinks);
if (Node) {
//
// Not inserting first node in tree
//
if (*Links) {
//
// Entry exists in the cache, so replace by swapping all splay links
//
RtlRightChild(&NewNode->CacheLinks) = RtlRightChild(*Links);
RtlLeftChild(&NewNode->CacheLinks) = RtlLeftChild(*Links);
if (RtlRightChild(*Links)) RtlParent(RtlRightChild(*Links)) = &NewNode->CacheLinks;
if (RtlLeftChild(*Links)) RtlParent(RtlLeftChild(*Links)) = &NewNode->CacheLinks;
if (!RtlIsRoot(*Links)) {
//
// Change over the parent links. Note that we've messed with *Links now
// since it is pointing at the parent member.
//
RtlParent(&NewNode->CacheLinks) = RtlParent(*Links);
if (RtlIsLeftChild(*Links)) {
RtlLeftChild(RtlParent(*Links)) = &NewNode->CacheLinks;
} else {
RtlRightChild(RtlParent(*Links)) = &NewNode->CacheLinks;
}
} else {
//
// Set root of the cache
//
Cache->Cache = &NewNode->CacheLinks;
}
//
// Free old node
//
RemoveEntryList(&Node->ListLinks);
FsRtlFreeTunnelNode(Node, &FreePoolList);
Cache->NumEntries--;
} else {
//
// Simple insertion as a leaf
//
NewNode->CacheLinks.Parent = &Node->CacheLinks;
*Links = &NewNode->CacheLinks;
}
} else {
Cache->Cache = &NewNode->CacheLinks;
}
//
// Thread onto the timer list
//
FsRtlQueryNormalizedSystemTime(&NewNode->CreateTime);
InsertTailList(&Cache->TimerQueue, &NewNode->ListLinks);
Cache->NumEntries++;
//
// Stash tunneling information
//
NewNode->DirKey = DirKey;
if (KeyByShortName) {
NewNode->Flags = TUNNEL_FLAG_KEY_SHORT;
} else {
NewNode->Flags = 0;
}
//
// Initialize the internal UNICODE_STRINGS to point at the buffer segments. For various
// reasons (UNICODE APIs are incomplete, we're avoiding calling any allocate routine more
// than once, UNICODE strings are not guaranteed to be null terminated) we have to do a lot
// of this by hand.
//
// The data is layed out like this in the allocated block:
//
// -----------------------------------------------------------------------------------
// | TUNNEL_NODE | Node->ShortName.Buffer | Node->LongName.Buffer | Node->TunnelData |
// -----------------------------------------------------------------------------------
//
NewNode->ShortName.Buffer = (PWCHAR)((PCHAR)NewNode + sizeof(TUNNEL_NODE));
NewNode->LongName.Buffer = (PWCHAR)((PCHAR)NewNode + sizeof(TUNNEL_NODE) + ShortName->Length);
NewNode->ShortName.Length = NewNode->ShortName.MaximumLength = ShortName->Length;
NewNode->LongName.Length = NewNode->LongName.MaximumLength = LongName->Length;
if (ShortName->Length) {
RtlCopyMemory(NewNode->ShortName.Buffer, ShortName->Buffer, ShortName->Length);
}
if (LongName->Length) {
RtlCopyMemory(NewNode->LongName.Buffer, LongName->Buffer, LongName->Length);
}
NewNode->TunnelData = (PVOID)((PCHAR)NewNode + sizeof(TUNNEL_NODE) + ShortName->Length + LongName->Length);
NewNode->TunnelDataLength = DataLength;
RtlCopyMemory(NewNode->TunnelData, Data, DataLength);
if (AllocatedFromPool) {
SetFlag(NewNode->Flags, TUNNEL_FLAG_NON_LOOKASIDE);
}
#if defined(TUNNELTEST) || defined (KEYVIEW)
DbgPrint("FsRtlAddToTunnelCache:\n");
DumpNode(NewNode, 1);
#ifndef KEYVIEW
DumpTunnel(Cache);
#endif
#endif // TUNNELTEST
//
// Clean out the cache, release, and then drop any pool memory we need to
//
FsRtlPruneTunnelCache(Cache, &FreePoolList);
ExReleaseFastMutex(&Cache->Mutex);
FsRtlEmptyFreePoolList(&FreePoolList);
return;
}
VOID
DumpTunnel (
PTUNNEL Tunnel
)
{
PRTL_SPLAY_LINKS SplayLinks, Ptr;
PTUNNEL_NODE Node;
PLIST_ENTRY Link;
ULONG Indent = 1, i;
ULONG EntryCount = 0;
BOOLEAN CountOff = FALSE;
DbgPrint("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");
DbgPrint("NumEntries = %d\n", Tunnel->NumEntries);
DbgPrint("****** Cache Tree\n");
SplayLinks = Tunnel->Cache;
if (SplayLinks == NULL) {
goto end;
}
while (RtlLeftChild(SplayLinks) != NULL) {
SplayLinks = RtlLeftChild(SplayLinks);
Indent++;
}
while (SplayLinks) {
Node = CONTAINING_RECORD( SplayLinks, TUNNEL_NODE, CacheLinks );
EntryCount++;
DumpNode(Node, Indent);
Ptr = SplayLinks;
/*
first check to see if there is a right subtree to the input link
if there is then the real successor is the left most node in
the right subtree. That is find and return P in the following diagram
Links
\
.
.
.
/
P
\
*/
if ((Ptr = RtlRightChild(SplayLinks)) != NULL) {
Indent++;
while (RtlLeftChild(Ptr) != NULL) {
Indent++;
Ptr = RtlLeftChild(Ptr);
}
SplayLinks = Ptr;
} else {
/*
we do not have a right child so check to see if have a parent and if
so find the first ancestor that we are a left decendent of. That
is find and return P in the following diagram
P
/
.
.
.
Links
*/
Ptr = SplayLinks;
while (RtlIsRightChild(Ptr)) {
Indent--;
Ptr = RtlParent(Ptr);
}
if (!RtlIsLeftChild(Ptr)) {
//
// we do not have a real successor so we simply return
// NULL
//
SplayLinks = NULL;
} else {
Indent--;
SplayLinks = RtlParent(Ptr);
}
}
}
end:
if (CountOff = (EntryCount != Tunnel->NumEntries)) {
DbgPrint("!!!!!!!!!! Splay Tree Count Mismatch (%d != %d)\n", EntryCount, Tunnel->NumEntries);
}
EntryCount = 0;
DbgPrint("****** Timer Queue\n");
for (Link = Tunnel->TimerQueue.Flink;
Link != &Tunnel->TimerQueue;
Link = Link->Flink) {
Node = CONTAINING_RECORD( Link, TUNNEL_NODE, ListLinks );
EntryCount++;
DumpNode(Node, 1);
}
if (CountOff |= (EntryCount != Tunnel->NumEntries)) {
DbgPrint("!!!!!!!!!! Timer Queue Count Mismatch (%d != %d)\n", EntryCount, Tunnel->NumEntries);
}
ASSERT(!CountOff);
DbgPrint("------------------------------------------------------------------\n");
}
static
VOID
SwapSplayLinks(PRTL_SPLAY_LINKS LinkA,
PRTL_SPLAY_LINKS LinkB)
{
if (RtlParent(LinkA) == LinkB || RtlIsRoot(LinkB)) {
PRTL_SPLAY_LINKS Tmp = LinkA;
LinkA = LinkB;
LinkB = Tmp;
}
{
RTL_SPLAY_LINKS Ta = *LinkA, Tb = *LinkB;
BOOLEAN RootA = RtlIsRoot(LinkA),
LeftA = RtlIsLeftChild(LinkA),
LeftB = RtlIsLeftChild(LinkB);
*LinkB = Ta; *LinkA = Tb;
// A was parent of B is a special case: A->Parent is now B
if (RtlParent(&Tb) == LinkA) {
if (!RootA) {
if (LeftA) {
RtlInsertAsLeftChild(RtlParent(&Ta), LinkB);
} else {
RtlInsertAsRightChild(RtlParent(&Ta), LinkB);
}
}
if (LeftB) {
RtlInsertAsLeftChild(LinkB, LinkA);
} else {
RtlInsertAsRightChild(LinkB, LinkA);
}
}
FixupChildLinks(LinkA, FALSE, LeftB);
FixupChildLinks(LinkB, RootA, LeftA);
// A was root is a special case: B->Parent is now B
if (RootA)
RtlParent(LinkB) = LinkB;
#ifdef VERIFY_SWAP_SPLAY_LINKS
// Verify the distinct cases of node swap
if (RootA) {
if (RtlParent(&Tb) == LinkA) {
// LinkA = D, LinkB = B
// D B S S.L S.R S Q Q.R
ASSERT(RtlParent(LinkA) == LinkB);
ASSERT(RtlLeftChild(LinkA) == RtlLeftChild(&Tb));
ASSERT(RtlRightChild(LinkA) == RtlRightChild(&Tb));
ASSERT(RtlParent(LinkB) == LinkB);
ASSERT(RtlLeftChild(LinkB) == (LeftB ? LinkA : RtlLeftChild(&Ta)));
ASSERT(RtlRightChild(LinkB) == (LeftB ? RtlRightChild(&Ta) : LinkA));
} else {
// LinkA = D, LinkB = A
// D A S.P S.L S.R S Q.L Q.R
ASSERT(RtlParent(LinkA) == RtlParent(&Tb));
ASSERT(RtlLeftChild(LinkA) == RtlLeftChild(&Tb));
ASSERT(RtlRightChild(LinkA) == RtlRightChild(&Tb));
ASSERT(RtlParent(LinkB) == LinkB);
ASSERT(RtlLeftChild(LinkB) == RtlLeftChild(&Ta));
ASSERT(RtlRightChild(LinkB) == RtlRightChild(&Ta));
}
} else {
if (RtlParent(&Tb) == LinkA) {
// LinkA = B, LinkB = A
// B A S S.L S.R Q.P Q Q.R
ASSERT(RtlParent(LinkA) == LinkB);
ASSERT(RtlLeftChild(LinkA) == RtlLeftChild(&Tb));
ASSERT(RtlRightChild(LinkA) == RtlRightChild(&Tb));
ASSERT(RtlParent(LinkB) == RtlParent(&Ta));
ASSERT(RtlLeftChild(LinkB) == (LeftB ? LinkA : RtlLeftChild(&Ta)));
ASSERT(RtlRightChild(LinkB) == (LeftB ? RtlRightChild(&Ta) : LinkA));
} else {
// LinkA = A, LinkB = C
// A C S.P S.L S.R Q.P Q.L Q.R
ASSERT(!memcmp(LinkA, &Tb, sizeof(Tb)));
ASSERT(!memcmp(LinkB, &Ta, sizeof(Ta)));
}
}
#endif
}
}
/*
* @implemented
*/
PRTL_SPLAY_LINKS
NTAPI
RtlSplay(PRTL_SPLAY_LINKS Links)
{
/*
* Implementation Notes (http://en.wikipedia.org/wiki/Splay_tree):
*
* To do a splay, we carry out a sequence of rotations,
* each of which moves the target node N closer to the root.
*
* Each particular step depends on only two factors:
* - Whether N is the left or right child of its parent node, P,
* - Whether P is the left or right child of its parent, G (for grandparent node).
*
* Thus, there are four cases:
* - Case 1: N is the left child of P and P is the left child of G.
* In this case we perform a double right rotation, so that
* P becomes N's right child, and G becomes P's right child.
*
* - Case 2: N is the right child of P and P is the right child of G.
* In this case we perform a double left rotation, so that
* P becomes N's left child, and G becomes P's left child.
*
* - Case 3: N is the left child of P and P is the right child of G.
* In this case we perform a rotation so that
* G becomes N's left child, and P becomes N's right child.
*
* - Case 4: N is the right child of P and P is the left child of G.
* In this case we perform a rotation so that
* P becomes N's left child, and G becomes N's right child.
*
* Finally, if N doesn't have a grandparent node, we simply perform a
* left or right rotation to move it to the root.
*
* By performing a splay on the node of interest after every operation,
* we keep recently accessed nodes near the root and keep the tree
* roughly balanced, so that we achieve the desired amortized time bounds.
*/
PRTL_SPLAY_LINKS N, P, G;
/* N is the item we'll be playing with */
N = Links;
/* Let the algorithm run until N becomes the root entry */
while (!RtlIsRoot(N))
{
/* Now get the parent and grand-parent */
P = RtlParent(N);
G = RtlParent(P);
/* Case 1 & 3: N is left child of P */
if (RtlIsLeftChild(N))
{
/* 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.
*/
RtlRightChild(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))
{
/*
* 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.
*/
RtlRightChild(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
{
/* P's left-child becomes N's right child */
RtlLeftChild(P) = RtlRightChild(N);
/* If it exists, update its parent pointer too */
if (RtlLeftChild(P)) RtlParent(RtlLeftChild(P)) = P;
/* Now make N the root, no need to worry about references */
N->Parent = N;
/* And make P its right child */
N->RightChild = P;
P->Parent = N;
}
}
/* Case 2 & 4: N is right child of P */
else
{
/* Case 2: P is the right child of G */
if (RtlIsRightChild(P))
{
/*
* P's left-child becomes G's right child and
* N's left-child becomes P's right child.
*/
RtlRightChild(G) = RtlLeftChild(P);
RtlRightChild(P) = RtlLeftChild(N);
/*
* If they exist, update their parent pointers too,
* since they've changed trees.
*/
if (RtlRightChild(G)) RtlParent(RtlRightChild(G)) = G;
if (RtlRightChild(P)) RtlParent(RtlRightChild(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.
*/
RtlRightChild(RtlParent(G)) = N;
}
}
/* Now N is on top, so P has become its child. */
RtlLeftChild(N) = P;
RtlParent(P) = N;
/* N is on top, P is its child, so G is grandchild. */
RtlLeftChild(P) = G;
RtlParent(G) = P;
}
/* Case 4: P is the left child of G */
else if (RtlIsLeftChild(P))
{
/*
* N's left-child becomes G's right child and
* N's right-child becomes P's left child.
*/
RtlRightChild(P) = RtlLeftChild(N);
RtlLeftChild(G) = RtlRightChild(N);
/*
* If they exist, update their parent pointers too,
* since they've changed trees.
*/
if (RtlRightChild(P)) RtlParent(RtlRightChild(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.
*/
RtlRightChild(RtlParent(G)) = N;
}
}
/* Now N is on top, so P has become its left child. */
RtlLeftChild(N) = P;
RtlParent(G) = N;
/* N is on top, P is its left child, so G is right child. */
RtlRightChild(N) = G;
RtlParent(P) = N;
}
/* "Finally" case: N doesn't have a grandparent => P is root */
else
{
/* P's right-child becomes N's left child */
RtlRightChild(P) = RtlLeftChild(N);
/* If it exists, update its parent pointer too */
if (RtlRightChild(P)) RtlParent(RtlRightChild(P)) = P;
/* Now make N the root, no need to worry about references */
N->Parent = N;
/* And make P its left child */
N->LeftChild = P;
P->Parent = N;
}
}
}
/* Return the root entry */
ASSERT(RtlIsRoot(N));
return N;
}
/*
* @implemented
*/
PRTL_SPLAY_LINKS
NTAPI
RtlDelete(PRTL_SPLAY_LINKS Links)
{
PRTL_SPLAY_LINKS N, P, C, SP;
N = Links;
/* Check if we have two children */
if ((RtlLeftChild(N)) && (RtlRightChild(N)))
{
/* Get the predecessor */
SP = RtlSubtreePredecessor(N);
/* Swap it with N, this will guarantee that N will have only a child */
SwapSplayLinks(SP, N);
}
/* Check if we have no children */
if (!(RtlLeftChild(N)) && !(RtlRightChild(N)))
{
/* If we are also the root, then the tree is gone */
if (RtlIsRoot(N)) return NULL;
/* Get our parent */
P = RtlParent(N);
/* Find out who is referencing us and delete the reference */
if (RtlIsLeftChild(N))
{
/* N was a left child, so erase its parent's left child link */
RtlLeftChild(RtlParent(N)) = NULL;
}
else
{
/* N was a right child, so erase its parent's right child link */
RtlRightChild(RtlParent(N)) = NULL;
}
/* And finally splay the parent */
return RtlSplay(P);
}
/* If we got here, we have a child (not two: we swapped above!) */
if (RtlLeftChild(N))
{
/* We have a left child, so get it */
C = RtlLeftChild(N);
}
else
{
/* We have a right child, get him instead */
C = RtlRightChild(N);
}
/* Check if we are the root entry */
if (RtlIsRoot(N))
{
/* Our child is now root, return him */
C->Parent = C;
return C;
}
/* Find out who is referencing us and link to our child instead */
if (RtlIsLeftChild(N))
{
/* N was a left child, so set its parent's left child as our child */
RtlLeftChild(RtlParent(N)) = C;
}
else
{
/* N was a right child, so set its parent's right child as our child */
RtlRightChild(RtlParent(N)) = C;
}
/* Finally, inherit our parent and splay the parent */
C->Parent = N->Parent;
return RtlSplay(RtlParent(C));
}
