Bool TreeTraverse(Tree tree,
TreeCompare compare,
TreeKeyMethod key,
TreeVisitor visit, void *closureP, Size closureS)
{
Tree parent, node;
AVERT(Tree, tree);
AVER(FUNCHECK(visit));
/* closureP, closureS arbitrary */
parent = TreeEMPTY;
node = tree;
if (node == TreeEMPTY)
return TRUE;
down:
if (TreeHasLeft(node)) {
node = stepDownLeft(node, &parent);
AVER(compare(parent, key(node)) == CompareLESS);
goto down;
}
if (!visit(node, closureP, closureS))
goto abort;
if (TreeHasRight(node)) {
node = stepDownRight(node, &parent);
AVER(compare(parent, key(node)) != CompareLESS);
goto down;
}
up:
if (parent == TreeEMPTY)
return TRUE;
if (compare(parent, key(node)) != CompareLESS) {
node = stepUpLeft(node, &parent);
goto up;
}
node = stepUpRight(node, &parent);
if (!visit(node, closureP, closureS))
goto abort;
if (!TreeHasRight(node))
goto up;
node = stepDownRight(node, &parent);
goto down;
abort:
if (parent == TreeEMPTY)
return FALSE;
if (compare(parent, key(node)) != CompareLESS)
node = stepUpLeft(node, &parent);
else
node = stepUpRight(node, &parent);
goto abort;
}
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;
}
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;
}
}
void SplayNodeInit(SplayTree splay, Tree node)
{
AVERT(SplayTree, splay);
AVERT(Tree, node);
AVER(!TreeHasLeft(node)); /* otherwise, call SplayNodeRefresh */
AVER(!TreeHasRight(node)); /* otherwise, call SplayNodeRefresh */
splay->updateNode(splay, node);
}
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 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 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;
}
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;
}
