BTree::Iterator
BTree::lowerBound(Key key)
{
BlockStack path;
keepTracingToLeaf(key, path);
return findInLeaf(path.top(), key);
}
void ReversePostOrderTraversal::analyze(Function& function)
{
typedef util::LargeSet<BasicBlock*> BlockSet;
typedef std::stack<BasicBlock*> BlockStack;
order.clear();
BlockSet visited;
BlockStack stack;
auto cfgAnalysis = getAnalysis("ControlFlowGraph");
auto cfg = static_cast<ControlFlowGraph*>(cfgAnalysis);
report("Creating reverse post order traversal over function '" +
function.name() + "'");
// reverse post order is reversed topological order
stack.push(&*function.entry_block());
while(order.size() != function.size())
{
if(stack.empty())
{
for(auto block : order)
{
auto successors = cfg->getSuccessors(*block);
for(auto successor : successors)
{
if(visited.insert(successor).second)
{
stack.push(successor);
break;
}
}
if(!stack.empty()) break;
}
}
assertM(!stack.empty(), (function.size() - order.size())
<< " blocks are not connected.");
while(!stack.empty())
{
BasicBlock* top = stack.top();
stack.pop();
auto successors = cfg->getSuccessors(*top);
for(auto successor : successors)
{
assert(successor != nullptr);
auto predecessors = cfg->getPredecessors(*successor);
bool allPredecessorsVisited = true;
for(auto predecessor : predecessors)
{
if(visited.count(predecessor) == 0)
{
allPredecessorsVisited = false;
break;
}
}
if(!allPredecessorsVisited) continue;
if(visited.insert(successor).second)
{
stack.push(successor);
}
}
order.push_back(top);
report(" " << top->name());
}
}
// reverse the order
std::reverse(order.begin(), order.end());
}
BTree::Iterator
BTree::insert(Key key)
{
BlockStack path;
keepTracingToLeaf(key, path);
if (getHeaderFromNode(path.top())->entry_count >= maximumEntryPerLeaf()) {
Iterator ret = end();
Length split_offset = getHeaderFromNode(path.top())->entry_count / 2;
Block new_node = splitLeaf(path.top(), split_offset);
Key split_key = makeKey(
getKeyFromLeafEntry(getFirstEntryInLeaf(new_node)).start(),
_key_size
);
if (maximumEntryPerLeaf() > 1 &&
_less(getPointerOfKey(key), getPointerOfKey(split_key))
) {
ret = insertInLeaf(path.top(), key);
}
else {
ret = insertInLeaf(new_node, key);
}
path.pop();
while (!path.empty() &&
getHeaderFromNode(path.top())->entry_count >= maximumEntryPerNode()) {
Block node_to_insert = std::move(new_node);
auto index_to_insert = node_to_insert.index();
auto split_offset = getHeaderFromNode(path.top())->entry_count / 2;
new_node = splitNode(path.top(), split_offset);
if (_less(getPointerOfKey(split_key), getKeyFromNodeEntry(getFirstEntryInNode(new_node)).start())) {
insertInNode(path.top(), split_key, index_to_insert);
}
else {
insertInNode(new_node, split_key, index_to_insert);
}
split_key = makeKey(
getKeyFromNodeEntry(getFirstEntryInNode(new_node)).start(),
_key_size
);
path.pop();
}
if (path.empty()) {
_root = newRoot(split_key, _root, new_node);
}
else {
insertInNode(path.top(), split_key, new_node.index());
}
return std::move(ret);
}
else {
return insertInLeaf(path.top(), key);
}
}
void
BTree::erase(Key key)
{
Buffer removal_key_buffer(_key_size);
Key removal_key(key);
if (_key_size > sizeof(Key::value)) {
std::copy(
key.pointer,
key.pointer + _key_size,
removal_key_buffer.content()
);
removal_key.pointer = removal_key_buffer.content();
}
BlockStack path;
keepTracingToLeaf(key, path);
Block leaf = std::move(path.top()); path.pop();
auto *header = getHeaderFromNode(leaf);
eraseInLeaf(leaf, key);
if (leaf.index() == _root.index()) {
return;
}
if (header->entry_count) {
Block &parent = path.top();
auto parent_last_entry = getLastEntryInNode(parent);
auto parent_last_index = getIndexFromNodeEntry(parent_last_entry);
updateKey(
path.top(),
makeKey(
getKeyFromLeafEntry(getFirstEntryInLeaf(leaf)).start(),
_key_size
),
leaf.index()
);
if (*parent_last_index == leaf.index()) {
return;
}
Block next_leaf = _accesser->aquire(header->next);
auto *next_header = getHeaderFromNode(next_leaf);
if (next_header->entry_count + header->entry_count > maximumEntryPerLeaf()) {
return;
}
if (_key_size >= sizeof(Key::value)) {
std::copy(
getKeyFromLeafEntry(getFirstEntryInLeaf(next_leaf)),
getKeyFromLeafEntry(getFirstEntryInLeaf(next_leaf)) + _key_size,
removal_key_buffer.content()
);
}
else {
removal_key = makeKey(
getKeyFromLeafEntry(getFirstEntryInLeaf(next_leaf)).start(),
_key_size
);
}
mergeLeaf(leaf, next_leaf);
_accesser->freeBlock(next_leaf.index());
}
else {
updateLinkBeforeFreeLeaf(leaf);
_accesser->freeBlock(leaf.index());
}
while (true) {
Block node = std::move(path.top()); path.pop();
auto *header = getHeaderFromNode(node);
eraseInNode(node, removal_key);
if (node.index() == _root.index()) {
if (header->entry_count == 0) {
auto prev_root_index = _root.index();
_root = _accesser->aquire(getMarkFromNode(node)->before);
_accesser->freeBlock(prev_root_index);
return;
}
return;
}
if (header->entry_count) {
Block &parent = path.top();
auto parent_last_entry = getLastEntryInNode(parent);
auto parent_last_index = getIndexFromNodeEntry(parent_last_entry);
updateKey(
parent,
makeKey(
getKeyFromNodeEntry(getFirstEntryInNode(node)).start(),
_key_size
),
node.index()
);
if (*parent_last_index == node.index()) {
return;
}
Block next_node = _accesser->aquire(header->next);
auto *next_header = getHeaderFromNode(next_node);
if (next_header->entry_count + header->entry_count > maximumEntryPerNode()) {
return;
}
if (_key_size > sizeof(Key::value)) {
std::copy(
getKeyFromNodeEntry(getFirstEntryInNode(next_node)),
getKeyFromNodeEntry(getFirstEntryInNode(next_node)) + _key_size,
removal_key_buffer.content()
);
}
else {
removal_key = makeKey(
getKeyFromNodeEntry(getFirstEntryInNode(next_node)).start(),
_key_size
);
}
mergeNode(node, next_node);
_accesser->freeBlock(next_node.index());
}
else {
updateLinkBeforeFreeNode(node);
_accesser->freeBlock(node.index());
}
}
}