Function splay 

pub unsafe fn splay<Spec, Data>(
    node: BstNodePtr<<Spec as BstSpec>::Data, <Spec as BstSpec>::Parent>,
) -> BstNodePtr<<Spec as BstSpec>::Data, <Spec as BstSpec>::Parent>
where
    Spec: BstSpec<Data = Data, Parent = WithParent<Data>>,

Moves node to the root of its auxiliary tree and returns the previous root.

Safety

node and every pointer reachable through its auxiliary-parent chain must refer to live nodes of the same tree.

Examples found in repository

crates/competitive/src/tree/top_tree.rs (line 381)

    unsafe fn splay_top(node: TopPtr<S, A>) {
        let root = if A::ROOT_TO_NODE_TOP_DOWN {
            unsafe {
                splay_operations::with_parent::splay::<TopBstSpec<S, A>, TopTreeData<S, A>>(node)
            }
        } else {
            unsafe {
                splay_operations::with_parent::splay_with_local_top_down::<
                    TopBstSpec<S, A>,
                    TopTreeData<S, A>,
                >(node)
            }
        };
        if root != node {
            unsafe {
                (*node.as_ptr()).data.belong = (*root.as_ptr()).data.belong.take();
            }
        }
    }

crates/competitive/src/tree/link_cut_tree.rs (line 216)

    unsafe fn splay(node: LinkCutPtr<S>) {
        let root = if S::ROOT_TO_NODE_TOP_DOWN {
            unsafe {
                splay_operations::with_parent::splay::<LinkCutBstSpec<S>, LinkCutData<S>>(node)
            }
        } else {
            unsafe {
                splay_operations::with_parent::splay_with_local_top_down::<
                    LinkCutBstSpec<S>,
                    LinkCutData<S>,
                >(node)
            }
        };
        if root != node {
            unsafe {
                LinkCutBstSpec::<S>::with_two_inner_mut(root, node, S::transfer_path_parent);
            }
        }
    }