(* Basic counting module. Copyright (C) 2006 Merjis Ltd. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA *) type 'a t = ('a, int ref) Hashtbl.t let create () = Hashtbl.create 13 let get_ref counter thing = try Hashtbl.find counter thing with Not_found -> let r = ref 0 in Hashtbl.add counter thing r; r let incr counter thing = let r = get_ref counter thing in incr r let decr counter thing = let r = get_ref counter thing in decr r let add counter thing n = let r = get_ref counter thing in r := !r + n let sub counter thing n = let r = get_ref counter thing in r := !r - n let set counter thing n = let r = get_ref counter thing in r := n (* Don't use get_ref, to avoid unnecessarily creating 'ref 0's. *) let get counter thing = try !(Hashtbl.find counter thing) with Not_found -> 0 (* This is a common pair of operations, worth optimising. *) let incr_get counter thing = let r = get_ref counter thing in Pervasives.incr r; !r let zero = Hashtbl.remove let read counter = let counts = Hashtbl.fold ( fun thing r xs -> let r = !r in if r <> 0 then (r, thing) :: xs else xs ) counter [] in List.sort (fun (a, _) (b, _) -> compare (b : int) (a : int)) counts let length = Hashtbl.length let total counter = let total = ref 0 in Hashtbl.iter (fun _ r -> total := !total + !r) counter; !total let clear = Hashtbl.clear