/*
* stack contains all ancestors of the node, stack.peek() is its parent.
*/
private void mutateUp(@NotNull final Deque<ChildReferenceTransient> stack, MutableNode node) {
while (!stack.isEmpty()) {
final ChildReferenceTransient parent = stack.pop();
final MutableNode mutableParent = parent.mutate(this);
mutableParent.setChild(parent.firstByte, node);
node = mutableParent;
}
}
@Override
public boolean add(@NotNull final ByteIterable key, @NotNull final ByteIterable value) {
final ByteIterator it = key.iterator();
NodeBase node = root;
MutableNode mutableNode = null;
final Deque<ChildReferenceTransient> stack = new ArrayDeque<>();
while (true) {
final NodeBase.MatchResult matchResult = node.matchesKeySequence(it);
final int matchingLength = matchResult.matchingLength;
if (matchingLength < 0) {
final MutableNode prefix =
node.getMutableCopy(this).splitKey(-matchingLength - 1, matchResult.keyByte);
if (matchResult.hasNext) {
prefix.hang(matchResult.nextByte, it).setValue(value);
} else {
prefix.setValue(value);
}
if (stack.isEmpty()) {
root = new MutableRoot(prefix, root.sourceAddress);
} else {
final ChildReferenceTransient parent = stack.pop();
mutableNode = parent.mutate(this);
mutableNode.setChild(parent.firstByte, prefix);
}
break;
}
if (!it.hasNext()) {
if (node.hasValue()) {
return false;
}
mutableNode = node.getMutableCopy(this);
mutableNode.setValue(value);
break;
}
final byte nextByte = it.next();
final NodeBase child = node.getChild(this, nextByte);
if (child == null) {
mutableNode = node.getMutableCopy(this);
if (mutableNode.hasChildren() || mutableNode.hasKey() || mutableNode.hasValue()) {
mutableNode.hang(nextByte, it).setValue(value);
} else {
mutableNode.setKeySequence(new ArrayByteIterable(nextByte, it));
mutableNode.setValue(value);
}
break;
}
stack.push(new ChildReferenceTransient(nextByte, node));
node = child;
}
++size;
mutateUp(stack, mutableNode);
TreeCursorMutable.notifyCursors(this);
return true;
}
private boolean deleteImpl(@NotNull final ByteIterable key) {
final ByteIterator it = key.iterator();
NodeBase node = root;
final Deque<ChildReferenceTransient> stack = new ArrayDeque<>();
for (; ; ) {
if (node == null || node.matchesKeySequence(it).matchingLength < 0) {
return false;
}
if (!it.hasNext()) {
break;
}
final byte nextByte = it.next();
stack.push(new ChildReferenceTransient(nextByte, node));
node = node.getChild(this, nextByte);
}
if (!node.hasValue()) {
return false;
}
--size;
MutableNode mutableNode = node.getMutableCopy(this);
ChildReferenceTransient parent = stack.peek();
final boolean hasChildren = mutableNode.hasChildren();
if (!hasChildren && parent != null) {
stack.pop();
mutableNode = parent.mutate(this);
mutableNode.removeChild(parent.firstByte);
if (!mutableNode.hasValue() && mutableNode.getChildrenCount() == 1) {
mutableNode.mergeWithSingleChild(this);
}
} else {
mutableNode.setValue(null);
if (!hasChildren) {
mutableNode.setKeySequence(ByteIterable.EMPTY);
} else if (mutableNode.getChildrenCount() == 1) {
mutableNode.mergeWithSingleChild(this);
}
}
mutateUp(stack, mutableNode);
return true;
}