INCLUDE "utils.ml"
module type SA =
  sig
    type data
    type t 
    val make : data -> t
    val node : t -> data
    val hash : t -> int
    val uid : t -> Uid.t
    val equal : t -> t -> bool

    val with_id : Uid.t -> t
 end

module type S =
  sig

    type data
    type t = private { id : Uid.t;
		       key : int;
		       node : data }
    val make : data -> t
    val node : t -> data
    val hash : t -> int
    val uid : t -> Uid.t
    val equal : t -> t -> bool


    val with_id : Uid.t -> t
  end

module Make (H : Hashtbl.HashedType) : S with type data = H.t =
struct
  let uid_make = Uid.make_maker()
  type data = H.t
  type t = { id : Uid.t;
	     key : int;
	     node : data }
  let node t = t.node
  let uid t = t.id
  let hash t = t.key
  let equal t1 t2 = t1 == t2
  module WH = Weak.Make( struct 
			   type _t = t 
			   type t = _t 
			   let hash = hash
			   let equal a b = a == b || H.equal a.node b.node 
			 end)
  let pool = WH.create MED_H_SIZE
  let make x = 
    let cell = { id = uid_make(); key = H.hash x; node = x } in
      WH.merge pool cell

  exception Found of t

  let with_id id = 
    try
      WH.iter (fun r -> if r.id == id then raise (Found r))  pool;      
      raise Not_found
    with
      | Found r -> r
      | e -> raise e
  ;;

end