Unique_time.ml

(***********************************************************************)
(* Unique_time.ml - Module to return unique time                       *)
(*                 @author Yaron M. Minsky                             *)
(*                                                                     *)
(* Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, *)
(*               2011, 2012, 2013  Yaron Minsky and Contributors       *)
(*                                                                     *)
(* This file is part of SKS.  SKS is free software; you can            *)
(* redistribute it and/or modify it under the terms of the GNU General *)
(* Public License as published by the Free Software Foundation; either *)
(* version 2 of the License, or (at your option) any later version.    *)
(*                                                                     *)
(* This program 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   *)
(* General Public License for more details.                            *)
(*                                                                     *)
(* You should have received a copy of the GNU General Public License   *)
(* along with this program; if not, write to the Free Software         *)
(* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 *)
(* USA or see <http://www.gnu.org/licenses/>.                          *)
(***********************************************************************)
let most_recent_unique_time : float ref  = ref 0.

let timestamp_delta = 0.000001

let get nil =
  let candidate = Unix.gettimeofday() in
  let final =
    match candidate > !most_recent_unique_time with
      true -> candidate
    | false -> !most_recent_unique_time +. timestamp_delta
  in
  most_recent_unique_time := final;
  final