(*
 * Graph: generic graph library
 * Copyright (C) 2004
 * Sylvain Conchon, Jean-Christophe Filliatre and Julien Signoles
 * 
 * This software is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License version 2, as published by the Free Software Foundation.
 * 
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * See the GNU Library General Public License version 2 for more details
 * (enclosed in the file LGPL).
 *)

(* $Id: gmap.ml,v 1.1 2004/10/20 09:59:56 signoles Exp $ *)

module Vertex
  (G_Init : sig
     type t
     module V : Sig.HASHABLE
     val fold_vertex : (V.t -> 'a -> 'a) -> t -> 'a -> 'a
   end)
  (G_Dest : sig
     type t
     type vertex
     val empty : unit -> t
     val add_vertex : t -> vertex -> t
   end) =
struct
  
  module H = Hashtbl.Make(G_Init.V)
    
  let vertices = H.create 97

  let convert_vertex f x =
    try 
      H.find vertices x
    with Not_found ->
      let x' = f x in
      H.add vertices x x';
      x'

  let map f g =
    H.clear vertices;
    G_Init.fold_vertex
      (fun x g -> G_Dest.add_vertex g (convert_vertex f x)) 
      g (G_Dest.empty ())

end

module Edge
  (G_Init : sig
     type t
     module E : Sig.HASHABLE
     val fold_edges_e : (E.t -> 'a -> 'a) -> t -> 'a -> 'a
   end)
  (G_Dest : sig
     type t
     type edge
     val empty : unit -> t
     val add_edge_e : t -> edge -> t
   end) =
  Vertex
    (struct include G_Init module V = E let fold_vertex = fold_edges_e end)
    (struct include G_Dest type vertex = edge let add_vertex = add_edge_e end)