imperativeBL.ml

open! DataStruct 

module type S = 
sig 
  type elt 
  val pqtree : elt PqTree.t
  val index : elt -> int 
end


module Make = 
  functor (T : S) -> 
  struct

    open PqTree
    type elt = T.elt 

    let max_nb_nodes = 3 * length T.pqtree
    let pool = ref (Pool.make_int_pool max_nb_nodes)
             
    let get_new_index () = 
      let (index, p) = Pool.get !pool in 
      pool := p;
      index 

    let free_index index = 
      pool := Pool.free index !pool

    type kind = L of T.elt | PNode | QNode 
    type status = Full | Partial | Empty 

    type node = int 

    let root = ref 0
    let parent = Array.make max_nb_nodes None 
    let next = Array.make max_nb_nodes None 
    let previous = Array.make max_nb_nodes None 
    let leftmost_child = Array.make max_nb_nodes None 
    let rightmost_child = Array.make max_nb_nodes None 
    let kind = Array.make max_nb_nodes PNode 
    let nb_children = Array.make max_nb_nodes 0

    let is_visited = Array.make max_nb_nodes false 
    let active_children = Array.make max_nb_nodes []
    let status = Array.make max_nb_nodes Empty 
    let visited = ref [] 

    let leaf = Array.make (length T.pqtree) (-1) 


    let clean_node node =
      if is_visited.(node) then 
        begin
          is_visited.(node) <- false;
          active_children.(node) <- [];
          status.(node) <- Empty
        end

    let clean () = 
      List.iter clean_node !visited;
      visited := [] 


    let free = free_index

            
    let add_child ?(left_of=None) p child =
      next.(child) <- left_of;
      parent.(child) <- Some p;
      nb_children.(p) <- nb_children.(p) + 1;