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 SplaySplay(SplayTree splay, TreeKey key,
TreeCompareFunction compare)
{
Compare cmp;
SplayStateStruct stateStruct;
#ifdef SPLAY_DEBUG
Count count = SplayDebugCount(splay);
#endif
/* Short-circuit common cases. Splay trees often bring recently
acccessed nodes to the root. */
if (SplayTreeIsEmpty(splay) ||
compare(SplayTreeRoot(splay), key) == CompareEQUAL)
return CompareEQUAL;
if (SplayHasUpdate(splay)) {
cmp = SplaySplitRev(&stateStruct, splay, key, compare);
SplayAssembleRev(splay, &stateStruct);
} else {
cmp = SplaySplitDown(&stateStruct, splay, key, compare);
SplayAssembleDown(splay, &stateStruct);
}
SplayTreeSetRoot(splay, stateStruct.middle);
#ifdef SPLAY_DEBUG
AVER(count == SplayDebugCount(splay));
#endif
return cmp;
}
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 SplayFindLast(Tree *nodeReturn, SplayTree splay,
SplayTestNodeFunction testNode,
SplayTestTreeFunction testTree,
void *testClosure)
{
SplayFindClosureStruct closureStruct;
Bool found;
AVER_CRITICAL(nodeReturn != NULL);
AVERT_CRITICAL(SplayTree, splay);
AVER_CRITICAL(FUNCHECK(testNode));
AVER_CRITICAL(FUNCHECK(testTree));
if (SplayTreeIsEmpty(splay) ||
!testTree(splay, SplayTreeRoot(splay), testClosure))
return FALSE; /* no suitable nodes in tree */
closureStruct.testClosure = testClosure;
closureStruct.testNode = testNode;
closureStruct.testTree = testTree;
closureStruct.splay = splay;
found = SplaySplay(splay, &closureStruct,
SplayFindLastCompare) == CompareEQUAL &&
closureStruct.found;
while (!found) {
Tree oldRoot, newRoot;
oldRoot = SplayTreeRoot(splay);
newRoot = TreeLeft(oldRoot);
if (newRoot == TreeEMPTY || !(*testTree)(splay, newRoot, testClosure))
return FALSE; /* no suitable nodes in the rest of the tree */
/* Temporarily chop off the right half-tree, inclusive of root,
so that the search excludes any nodes we've seen already. */
SplayTreeSetRoot(splay, newRoot);
TreeSetLeft(oldRoot, TreeEMPTY);
found = SplaySplay(splay, &closureStruct,
SplayFindLastCompare) == CompareEQUAL &&
closureStruct.found;
/* Restore the right tree, then rotate right so that the node we
just splayed is at the root. Update both. */
newRoot = SplayTreeRoot(splay);
TreeSetLeft(oldRoot, newRoot);
SplayTreeSetRoot(splay, oldRoot);
TreeRotateRight(&splay->root);
splay->updateNode(splay, oldRoot);
splay->updateNode(splay, newRoot);
}
*nodeReturn = SplayTreeRoot(splay);
return TRUE;
}
Bool SplayTreeNeighbours(Tree *leftReturn, Tree *rightReturn,
SplayTree splay, TreeKey key)
{
SplayStateStruct stateStruct;
Bool found;
Compare cmp;
#ifdef SPLAY_DEBUG
Count count = SplayDebugCount(splay);
#endif
AVERT(SplayTree, splay);
AVER(leftReturn != NULL);
AVER(rightReturn != NULL);
if (SplayTreeIsEmpty(splay)) {
*leftReturn = *rightReturn = TreeEMPTY;
return TRUE;
}
cmp = SplaySplit(&stateStruct, splay, key, splay->compare);
switch (cmp) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareEQUAL:
found = FALSE;
break;
case CompareLESS:
AVER(!TreeHasLeft(stateStruct.middle));
*rightReturn = stateStruct.middle;
*leftReturn = stateStruct.leftLast;
found = TRUE;
break;
case CompareGREATER:
AVER(!TreeHasRight(stateStruct.middle));
*leftReturn = stateStruct.middle;
*rightReturn = stateStruct.rightFirst;
found = TRUE;
break;
}
SplayAssemble(splay, &stateStruct);
SplayTreeSetRoot(splay, stateStruct.middle);
#ifdef SPLAY_DEBUG
AVER(count == SplayDebugCount(splay));
#endif
return found;
}
Bool SplayTreeFind(Tree *nodeReturn, SplayTree splay, TreeKey key) {
AVERT(SplayTree, splay);
AVER(nodeReturn != NULL);
if (SplayTreeIsEmpty(splay))
return FALSE;
if (SplaySplay(splay, key, splay->compare) != CompareEQUAL)
return FALSE;
*nodeReturn = SplayTreeRoot(splay);
return TRUE;
}
void SplayNodeRefresh(SplayTree splay, Tree node)
{
Compare cmp;
AVERT(SplayTree, splay);
AVERT(Tree, node);
AVER(!SplayTreeIsEmpty(splay)); /* must contain node, at least */
cmp = SplaySplay(splay, splay->nodeKey(node), splay->compare);
AVER(cmp == CompareEQUAL);
AVER(SplayTreeRoot(splay) == node);
splay->updateNode(splay, node);
}
Tree SplayTreeFirst(SplayTree splay) {
Tree node;
AVERT(SplayTree, splay);
if (SplayTreeIsEmpty(splay))
return TreeEMPTY;
(void)SplaySplay(splay, NULL, compareLess);
node = SplayTreeRoot(splay);
AVER(node != TreeEMPTY);
AVER(TreeLeft(node) == TreeEMPTY);
return node;
}
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;
}
Tree SplayTreeNext(SplayTree splay, TreeKey oldKey) {
AVERT(SplayTree, splay);
if (SplayTreeIsEmpty(splay))
return TreeEMPTY;
/* Make old node the root. Probably already is. We don't mind if the
node has been deleted, or replaced by a node with the same key. */
switch (SplaySplay(splay, oldKey, splay->compare)) {
default:
NOTREACHED;
/* defensive fall-through */
case CompareLESS:
return SplayTreeRoot(splay);
case CompareGREATER:
case CompareEQUAL:
return SplayTreeSuccessor(splay);
}
}
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 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;
}
