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;
}
void TreeBalance(Tree *treeIO)
{
Count depth;
AVER(treeIO != NULL);
AVERT(Tree, *treeIO);
depth = TreeToVine(treeIO);
if (depth > 2) {
Count n = depth - 1;
do {
Count m = n / 2, i;
Tree *link = treeIO;
for (i = 0; i < m; ++i) {
TreeRotateLeft(link);
link = &((*link)->right);
}
n = n - m - 1;
} while (n > 1);
}
}