private STNode AddLastPrivate(STNode node) {
var second = FirstChild;
if (second == null) {
node.Parent = This;
node.Next = node;
node.Prev = node;
FirstChild = node;
} else {
second.AddPrevIgnoringFirstChild(node);
}
return node;
}
private static void ToStringPrivate(
STNode node, int depth, StringBuilder builder) {
if (node == null) {
return;
}
for (int i = 0; i < depth; i++) {
builder.Append(" ");
}
builder.AppendLine(node.Value.ToString());
foreach (var child in node.Children) {
ToStringPrivate(child, depth + 1, builder);
}
}
public STNode AddLast(STNode node) {
Contract.Requires(node != null);
Contract.Requires(node.Parent == null);
return AddLastPrivate(node);
}
private STNode AddPrevIgnoringFirstChild(STNode node) {
node.Parent = This.Parent;
node.Next = This;
node.Prev = Prev;
Prev.Next = node;
Prev = node;
return node;
}
private STNode AddFirstPrivate(STNode node) {
AddLastPrivate(node);
FirstChild = node;
return node;
}
public STNode AddNext(STNode node) {
Contract.Requires(node != null);
Contract.Requires(node.Parent == null);
Contract.Requires(Parent != null);
return This.Next.AddPrevIgnoringFirstChild(node);
}
public STNode AddPrev(STNode node) {
Contract.Requires(node != null);
Contract.Requires(node.Parent == null);
Contract.Requires(Parent != null);
if (Parent.FirstChild == This) {
Parent.FirstChild = node;
}
return AddPrevIgnoringFirstChild(node);
}