(* md5 helpers *)
let md5_create files reg =
  let opts = "md5sum " ^ String.concat " " files ^ " > " ^ reg in
  let rc = Unix.system opts in
  match rc with
  | Unix.WEXITED 0 -> ()
  | Unix.WEXITED i -> raise (Failure "Unable to create the md5sums file")
  | _ -> assert false 

let md5_check reg = 
  let opts = "md5sum -c " ^ reg in
  let rc = Unix.system opts in
  match rc with
  | Unix.WEXITED 0 -> true
  | Unix.WEXITED _ -> false 
  | _ -> assert false 

let reg () = (Lazy.force Http_getter_env.dump_file) ^ ".md5"

(* sync checks *)

(* maybe should be useda as a fallback *)
(*
let is_in_sync_date () =
  let get_last_mod_date f =
    try 
      (Unix.stat f).Unix.st_mtime
    with 
    | Unix.Unix_error (Unix.ENOENT, _, _)-> 0.0 
  in
  let map_date = get_last_mod_date (Lazy.force Http_getter_env.cic_dbm_real) in
  let dump_date = get_last_mod_date (Lazy.force Http_getter_env.dump_file) in
  dump_date < map_date
*)

let check_hash () =
  md5_check (reg ())

let create_hash files = 
  md5_create files (reg ())