static Tree SplayZagZagRev(Tree middle, Tree *leftLastIO)
{
Tree child;
AVERT_CRITICAL(Tree, middle);
AVER_CRITICAL(leftLastIO != NULL);
AVERT_CRITICAL(Tree, *leftLastIO);
child = TreeRight(middle);
TreeSetRight(middle, TreeRight(*leftLastIO));
TreeSetRight(*leftLastIO, TreeLeft(middle));
TreeSetLeft(middle, *leftLastIO);
*leftLastIO = middle;
return child;
}
static Tree SplayTreeSuccessor(SplayTree splay)
{
Tree oldRoot, newRoot;
AVERT(SplayTree, splay);
AVER(!SplayTreeIsEmpty(splay));
oldRoot = SplayTreeRoot(splay);
if (!TreeHasRight(oldRoot))
return TreeEMPTY; /* No successor */
/* temporarily chop off the left half-tree, inclusive of root */
SplayTreeSetRoot(splay, TreeRight(oldRoot));
TreeSetRight(oldRoot, TreeEMPTY);
(void)SplaySplay(splay, NULL, compareLess);
newRoot = SplayTreeRoot(splay);
AVER(newRoot != TreeEMPTY);
AVER(TreeLeft(newRoot) == TreeEMPTY);
TreeSetLeft(newRoot, oldRoot);
splay->updateNode(splay, oldRoot);
splay->updateNode(splay, newRoot);
return newRoot;
}
Bool SplayFindFirst(Tree *nodeReturn, SplayTree splay,
SplayTestNodeFunction testNode,
SplayTestTreeFunction testTree,
void *closureP, Size closureS)
{
SplayFindClosureStruct closureStruct;
Bool found;
AVER(nodeReturn != NULL);
AVERT(SplayTree, splay);
AVER(FUNCHECK(testNode));
AVER(FUNCHECK(testTree));
if (SplayTreeIsEmpty(splay) ||
!testTree(splay, SplayTreeRoot(splay), closureP, closureS))
return FALSE; /* no suitable nodes in tree */
closureStruct.p = closureP;
closureStruct.s = closureS;
closureStruct.testNode = testNode;
closureStruct.testTree = testTree;
closureStruct.splay = splay;
closureStruct.found = FALSE;
found = SplaySplay(splay, &closureStruct,
SplayFindFirstCompare) == CompareEQUAL &&
closureStruct.found;
while (!found) {
Tree oldRoot, newRoot;
/* FIXME: Rename to "seen" and "not yet seen" or something. */
oldRoot = SplayTreeRoot(splay);
newRoot = TreeRight(oldRoot);
if (newRoot == TreeEMPTY || !(*testTree)(splay, newRoot, closureP, closureS))
return FALSE; /* no suitable nodes in the rest of the tree */
/* Temporarily chop off the left half-tree, inclusive of root,
so that the search excludes any nodes we've seen already. */
SplayTreeSetRoot(splay, newRoot);
TreeSetRight(oldRoot, TreeEMPTY);
found = SplaySplay(splay, &closureStruct,
SplayFindFirstCompare) == CompareEQUAL &&
closureStruct.found;
/* Restore the left tree, then rotate left so that the node we
just splayed is at the root. Update both. */
newRoot = SplayTreeRoot(splay);
TreeSetRight(oldRoot, newRoot);
SplayTreeSetRoot(splay, oldRoot);
TreeRotateLeft(&splay->root);
splay->updateNode(splay, oldRoot);
splay->updateNode(splay, newRoot);
}
*nodeReturn = SplayTreeRoot(splay);
return TRUE;
}
static Compare SplayFindLastCompare(Tree node, TreeKey key)
{
SplayFindClosure my;
SplayTestNodeFunction testNode;
SplayTestTreeFunction testTree;
void *testClosure;
SplayTree splay;
AVERT_CRITICAL(Tree, node);
AVER_CRITICAL(key != NULL);
/* Lift closure values into variables so that they aren't aliased by
calls to the test functions. */
my = (SplayFindClosure)key;
testClosure = my->testClosure;
testNode = my->testNode;
testTree = my->testTree;
splay = my->splay;
if (TreeHasRight(node) &&
(*testTree)(splay, TreeRight(node), testClosure)) {
return CompareGREATER;
} else if ((*testNode)(splay, node, testClosure)) {
my->found = TRUE;
return CompareEQUAL;
} else {
/* See SplayFindFirstCompare. */
if (TreeHasLeft(node) &&
!(*testTree)(splay, TreeLeft(node), testClosure)) {
my->found = FALSE;
return CompareEQUAL;
}
return CompareLESS;
}
}
static Tree stepDownRight(Tree node, Tree *parentIO)
{
Tree parent = *parentIO;
Tree child = TreeRight(node);
TreeSetRight(node, parent);
*parentIO = node;
return child;
}
static Tree stepUpLeft(Tree node, Tree *parentIO)
{
Tree parent = *parentIO;
Tree grandparent = TreeRight(parent);
TreeSetRight(parent, node);
*parentIO = grandparent;
return parent;
}
static Tree SplayZag(Tree middle, Tree *leftLastIO, Tree *leftPrevReturn)
{
AVERT_CRITICAL(Tree, middle);
AVER_CRITICAL(leftLastIO != NULL);
AVERT_CRITICAL(Tree, *leftLastIO);
TreeSetRight(*leftLastIO, middle);
*leftPrevReturn = *leftLastIO;
*leftLastIO = middle;
return TreeRight(middle);
}
void SplayDebugUpdate(SplayTree splay, Tree tree)
{
AVERT(SplayTree, splay);
AVERT(Tree, tree);
if (tree == TreeEMPTY)
return;
SplayDebugUpdate(splay, TreeLeft(tree));
SplayDebugUpdate(splay, TreeRight(tree));
splay->updateNode(splay, tree);
}
Bool SplayTreeInsert(SplayTree splay, Tree node)
{
Tree neighbour;
AVERT(SplayTree, splay);
AVERT(Tree, node);
AVER(TreeLeft(node) == TreeEMPTY);
AVER(TreeRight(node) == TreeEMPTY);
if (SplayTreeIsEmpty(splay)) {
SplayTreeSetRoot(splay, node);
return TRUE;
}
switch (SplaySplay(splay, splay->nodeKey(node), splay->compare)) {
default:
NOTREACHED;
/* fall through */
case CompareEQUAL: /* duplicate node */
return FALSE;
case CompareGREATER: /* left neighbour is at root */
neighbour = SplayTreeRoot(splay);
SplayTreeSetRoot(splay, node);
TreeSetRight(node, TreeRight(neighbour));
TreeSetLeft(node, neighbour);
TreeSetRight(neighbour, TreeEMPTY);
break;
case CompareLESS: /* right neighbour is at root */
neighbour = SplayTreeRoot(splay);
SplayTreeSetRoot(splay, node);
TreeSetLeft(node, TreeLeft(neighbour));
TreeSetRight(node, neighbour);
TreeSetLeft(neighbour, TreeEMPTY);
break;
}
splay->updateNode(splay, neighbour);
splay->updateNode(splay, node);
return TRUE;
}
static Tree SplayZigZig(Tree middle, Tree *rightFirstIO, Tree rightNext)
{
AVERT_CRITICAL(Tree, middle);
AVER_CRITICAL(rightFirstIO != NULL);
AVERT_CRITICAL(Tree, *rightFirstIO);
TreeSetLeft(*rightFirstIO, TreeRight(middle));
TreeSetRight(middle, *rightFirstIO);
TreeSetLeft(rightNext, middle);
*rightFirstIO = middle;
return TreeLeft(middle);
}
static Tree SplayZigZigRev(Tree middle, Tree *rightFirstIO)
{
Tree child;
AVERT_CRITICAL(Tree, middle);
AVER_CRITICAL(rightFirstIO != NULL);
AVERT_CRITICAL(Tree, *rightFirstIO);
child = TreeLeft(middle);
TreeSetLeft(middle, TreeLeft(*rightFirstIO));
TreeSetLeft(*rightFirstIO, TreeRight(middle));
TreeSetRight(middle, *rightFirstIO);
*rightFirstIO = middle;
return child;
}
Bool SplayTreeDelete(SplayTree splay, Tree node)
{
Tree leftLast;
Compare cmp;
AVERT(SplayTree, splay);
AVERT(Tree, node);
if (SplayTreeIsEmpty(splay))
return FALSE;
cmp = SplaySplay(splay, splay->nodeKey(node), splay->compare);
AVER(cmp != CompareEQUAL || SplayTreeRoot(splay) == node);
if (cmp != CompareEQUAL) {
return FALSE;
} else if (!TreeHasLeft(node)) {
SplayTreeSetRoot(splay, TreeRight(node));
TreeClearRight(node);
} else if (!TreeHasRight(node)) {
SplayTreeSetRoot(splay, TreeLeft(node));
TreeClearLeft(node);
} else {
Tree rightHalf = TreeRight(node);
TreeClearRight(node);
SplayTreeSetRoot(splay, TreeLeft(node));
TreeClearLeft(node);
(void)SplaySplay(splay, NULL, compareGreater);
leftLast = SplayTreeRoot(splay);
AVER(leftLast != TreeEMPTY);
AVER(!TreeHasRight(leftLast));
TreeSetRight(leftLast, rightHalf);
splay->updateNode(splay, leftLast);
}
TreeFinish(node);
return TRUE;
}
static Count TreeDebugCountBetween(Tree node,
TreeCompare compare, TreeKeyMethod key,
TreeKey min, TreeKey max)
{
if (node == TreeEMPTY)
return 0;
AVERT(Tree, node);
AVER(min == NULL || compare(node, min) != CompareGREATER);
AVER(max == NULL || compare(node, max) != CompareLESS);
return TreeDebugCountBetween(TreeLeft(node), compare, key, min, key(node)) +
1 +
TreeDebugCountBetween(TreeRight(node), compare, key, key(node), max);
}
static Tree SplayUpdateRightSpine(SplayTree splay, Tree node, Tree child)
{
AVERT_CRITICAL(SplayTree, splay);
AVERT_CRITICAL(Tree, node);
AVERT_CRITICAL(Tree, child);
while (node != TreeEMPTY) {
Tree parent = TreeRight(node);
TreeSetRight(node, child); /* un-reverse pointer */
splay->updateNode(splay, node);
child = node;
node = parent;
}
return child;
}
void TreeRotateRight(Tree *treeIO) {
Tree tree, left;
AVER(treeIO != NULL);
tree = *treeIO;
AVERT(Tree, tree);
left = TreeLeft(tree);
AVERT(Tree, left);
TreeSetLeft(*treeIO, TreeRight(left));
TreeSetRight(left, *treeIO);
*treeIO = left;
}
void TreeRotateLeft(Tree *treeIO)
{
Tree tree, right;
AVER(treeIO != NULL);
tree = *treeIO;
AVERT(Tree, tree);
right = TreeRight(tree);
AVERT(Tree, right);
TreeSetRight(tree, TreeLeft(right));
TreeSetLeft(right, tree);
*treeIO = right;
}
static Res SplayNodeDescribe(Tree node, mps_lib_FILE *stream,
TreeDescribeFunction nodeDescribe)
{
Res res;
if (!TreeCheck(node))
return ResFAIL;
if (stream == NULL)
return ResFAIL;
if (nodeDescribe == NULL)
return ResFAIL;
res = WriteF(stream, 0, "( ", NULL);
if (res != ResOK)
return res;
if (TreeHasLeft(node)) {
res = SplayNodeDescribe(TreeLeft(node), stream, nodeDescribe);
if (res != ResOK)
return res;
res = WriteF(stream, 0, " / ", NULL);
if (res != ResOK)
return res;
}
res = (*nodeDescribe)(node, stream);
if (res != ResOK)
return res;
if (TreeHasRight(node)) {
res = WriteF(stream, 0, " \\ ", NULL);
if (res != ResOK)
return res;
res = SplayNodeDescribe(TreeRight(node), stream, nodeDescribe);
if (res != ResOK)
return res;
}
res = WriteF(stream, 0, " )", NULL);
if (res != ResOK)
return res;
return ResOK;
}
Tree TreeReverseRightSpine(Tree tree)
{
Tree node, parent;
AVERT(Tree, tree);
parent = TreeEMPTY;
node = tree;
while (node != TreeEMPTY) {
Tree child = TreeRight(node);
TreeSetRight(node, parent);
parent = node;
node = child;
}
return parent;
}
static void SplayAssembleRev(SplayTree splay, SplayState state)
{
Tree left, right;
AVERT(SplayTree, splay);
AVER(state->middle != TreeEMPTY);
left = TreeLeft(state->middle);
left = SplayUpdateRightSpine(splay, state->leftLast, left);
TreeSetLeft(state->middle, left);
right = TreeRight(state->middle);
right = SplayUpdateLeftSpine(splay, state->rightFirst, right);
TreeSetRight(state->middle, right);
splay->updateNode(splay, state->middle);
}
static void SplayAssembleDown(SplayTree splay, SplayState state)
{
AVERT(SplayTree, splay);
AVER(state->middle != TreeEMPTY);
AVER(!SplayHasUpdate(splay));
if (state->left != TreeEMPTY) {
AVER_CRITICAL(state->leftLast != TreeEMPTY);
TreeSetRight(state->leftLast, TreeLeft(state->middle));
TreeSetLeft(state->middle, state->left);
}
if (state->right != TreeEMPTY) {
AVER_CRITICAL(state->rightFirst != TreeEMPTY);
TreeSetLeft(state->rightFirst, TreeRight(state->middle));
TreeSetRight(state->middle, state->right);
}
}
static Compare SplayFindFirstCompare(Tree node, TreeKey key)
{
SplayFindClosure closure;
void *closureP;
Size closureS;
SplayTestNodeFunction testNode;
SplayTestTreeFunction testTree;
SplayTree splay;
AVERT(Tree, node);
AVER(key != NULL);
/* Lift closure values into variables so that they aren't aliased by
calls to the test functions. */
closure = (SplayFindClosure)key;
closureP = closure->p;
closureS = closure->s;
testNode = closure->testNode;
testTree = closure->testTree;
splay = closure->splay;
if (TreeHasLeft(node) &&
(*testTree)(splay, TreeLeft(node), closureP, closureS)) {
return CompareLESS;
} else if ((*testNode)(splay, node, closureP, closureS)) {
closure->found = TRUE;
return CompareEQUAL;
} else {
/* If there's a right subtree but it doesn't satisfy the tree test
then we want to terminate the splay right now. SplaySplay will
return TRUE, so the caller must check closure->found to find out
whether the result node actually satisfies testNode. */
if (TreeHasRight(node) &&
!(*testTree)(splay, TreeRight(node), closureP, closureS)) {
closure->found = FALSE;
return CompareEQUAL;
}
return CompareGREATER;
}
}
static Compare SplayFindLastCompare(Tree node, TreeKey key)
{
SplayFindClosure closure;
void *closureP;
Size closureS;
SplayTestNodeFunction testNode;
SplayTestTreeFunction testTree;
SplayTree splay;
AVERT(Tree, node);
AVER(key != NULL);
/* Lift closure values into variables so that they aren't aliased by
calls to the test functions. */
closure = (SplayFindClosure)key;
closureP = closure->p;
closureS = closure->s;
testNode = closure->testNode;
testTree = closure->testTree;
splay = closure->splay;
if (TreeHasRight(node) &&
(*testTree)(splay, TreeRight(node), closureP, closureS)) {
return CompareGREATER;
} else if ((*testNode)(splay, node, closureP, closureS)) {
closure->found = TRUE;
return CompareEQUAL;
} else {
/* See SplayFindFirstCompare. */
if (TreeHasLeft(node) &&
!(*testTree)(splay, TreeLeft(node), closureP, closureS)) {
closure->found = FALSE;
return CompareEQUAL;
}
return CompareLESS;
}
}
static Compare SplaySplitRev(SplayStateStruct *stateReturn,
SplayTree splay, TreeKey key,
TreeCompareFunction compare)
{
Tree middle, leftLast, rightFirst;
Compare cmp;
AVERT(SplayTree, splay);
AVER(FUNCHECK(compare));
AVER(!SplayTreeIsEmpty(splay));
leftLast = TreeEMPTY;
rightFirst = TreeEMPTY;
middle = SplayTreeRoot(splay);
for (;;) {
cmp = compare(middle, key);
switch(cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
goto stop;
case CompareLESS:
if (!TreeHasLeft(middle))
goto stop;
middle = SplayZigRev(middle, &rightFirst);
cmp = compare(middle, key);
switch(cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
goto stop;
case CompareLESS:
if (!TreeHasLeft(middle))
goto stop;
middle = SplayZigZigRev(middle, &rightFirst);
splay->updateNode(splay, TreeRight(rightFirst));
break;
case CompareGREATER:
if (!TreeHasRight(middle))
goto stop;
middle = SplayZagRev(middle, &leftLast);
break;
}
break;
case CompareGREATER:
if (!TreeHasRight(middle))
goto stop;
middle = SplayZagRev(middle, &leftLast);
cmp = compare(middle, key);
switch(cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
goto stop;
case CompareGREATER:
if (!TreeHasRight(middle))
goto stop;
middle = SplayZagZagRev(middle, &leftLast);
splay->updateNode(splay, TreeLeft(leftLast));
break;
case CompareLESS:
if (!TreeHasLeft(middle))
goto stop;
middle = SplayZigRev(middle, &rightFirst);
break;
}
break;
}
}
stop:
stateReturn->middle = middle;
stateReturn->leftLast = leftLast;
stateReturn->rightFirst = rightFirst;
return cmp;
}
static Compare SplaySplitDown(SplayStateStruct *stateReturn,
SplayTree splay, TreeKey key,
TreeCompareFunction compare)
{
TreeStruct sentinel;
Tree middle, leftLast, rightFirst, leftPrev, rightNext;
Compare cmp;
AVERT(SplayTree, splay);
AVER(FUNCHECK(compare));
AVER(!SplayTreeIsEmpty(splay));
AVER(!SplayHasUpdate(splay));
TreeInit(&sentinel);
leftLast = &sentinel;
rightFirst = &sentinel;
middle = SplayTreeRoot(splay);
for (;;) {
cmp = compare(middle, key);
switch(cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
goto stop;
case CompareLESS:
if (!TreeHasLeft(middle))
goto stop;
middle = SplayZig(middle, &rightFirst, &rightNext);
cmp = compare(middle, key);
switch(cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
goto stop;
case CompareLESS:
if (!TreeHasLeft(middle))
goto stop;
middle = SplayZigZig(middle, &rightFirst, rightNext);
break;
case CompareGREATER:
if (!TreeHasRight(middle))
goto stop;
middle = SplayZag(middle, &leftLast, &leftPrev);
break;
}
break;
case CompareGREATER:
if (!TreeHasRight(middle))
goto stop;
middle = SplayZag(middle, &leftLast, &leftPrev);
cmp = compare(middle, key);
switch(cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
goto stop;
case CompareGREATER:
if (!TreeHasRight(middle))
goto stop;
middle = SplayZagZag(middle, &leftLast, leftPrev);
break;
case CompareLESS:
if (!TreeHasLeft(middle))
goto stop;
middle = SplayZig(middle, &rightFirst, &rightNext);
break;
}
break;
}
}
stop:
stateReturn->middle = middle;
stateReturn->left = TreeRight(&sentinel);
stateReturn->leftLast = leftLast == &sentinel ? TreeEMPTY : leftLast;
stateReturn->right = TreeLeft(&sentinel);
stateReturn->rightFirst = rightFirst == &sentinel ? TreeEMPTY : rightFirst;
return cmp;
}