Quellcode-Bibliothek

^© Kompilation durch diese Firma

[Weder Korrektheit noch Funktionsfähigkeit der Software werden zugesichert.]

Datei: tQueue.ml Sprache: SML

Original von: Coq^©

(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
(* <O___,, *       (see CREDITS file for the list of authors)           *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
(************************************************************************)

module PriorityQueue : sig
  type 'a t
  val create : unit -> 'a t
  val set_rel : ('a -> 'a -> int) -> 'a t -> unit
  val is_empty : 'a t -> bool
  val exists : ('a -> bool) -> 'a t -> bool
  val pop : ?picky:('a -> bool) -> 'a t -> 'a
  val push : 'a t -> 'a -> unit
  val clear : 'a t -> unit
  val length : 'a t -> int
end = struct
  type 'a item = int * 'a
  type 'a rel = 'a item -> 'a item -> int
  type 'a t = ('a item list * 'a rel) ref
  let sort_timestamp (i,_) (j,_) = i - j
  let age = ref 0
  let create () = ref ([],sort_timestamp)
  let is_empty t = fst !t = []
  let exists p t = List.exists (fun (_,x) -> p x) (fst !t)
  let pop ?(picky=(fun _ -> true)) ({ contents = (l, rel) } as t) =
    let rec aux acc = function
      | [] -> raise Queue.Empty
      | (_,x) :: xs when picky x -> t := (List.rev acc @ xs, rel); x
      | (_,x) as hd :: xs -> aux (hd :: acc) xs in
    aux [] l
  let push ({ contents = (xs, rel) } as t) x =
    incr age;
    (* re-roting the whole list is not the most efficient way... *)
    t := (List.sort rel (xs @ [!age,x]), rel)
  let clear ({ contents = (l, rel) } as t) = t := ([], rel)
  let set_rel rel ({ contents = (xs, _) } as t) =
    let rel (_,x) (_,y) = rel x y in
    t := (List.sort rel xs, rel)
  let length ({ contents = (l, _) }) = List.length l
end

type 'a t = {
  queue: 'a PriorityQueue.t;
  lock : Mutex.t;
  cond : Condition.t;
  mutable nwaiting : int;
  cond_waiting : Condition.t;
  mutable release : bool;
}

exception BeingDestroyed

let create () = {
  queue = PriorityQueue.create ();
  lock = Mutex.create ();
  cond = Condition.create ();
  nwaiting = 0;
  cond_waiting = Condition.create ();
  release = false;
}

let pop ?(picky=(fun _ -> true)) ?(destroy=ref false)
  ({ queue = q; lock = m; cond = c; cond_waiting = cn } as tq)
=
  Mutex.lock m;
  if tq.release then (Mutex.unlock m; raise BeingDestroyed);
  while not (PriorityQueue.exists picky q || !destroy) do
    tq.nwaiting <- tq.nwaiting + 1;
    Condition.broadcast cn;
    Condition.wait c m;
    tq.nwaiting <- tq.nwaiting - 1;
    if tq.release || !destroy then (Mutex.unlock m; raise BeingDestroyed)
  done;
  if !destroy then (Mutex.unlock m; raise BeingDestroyed);
  let x = PriorityQueue.pop ~picky q in
  Condition.signal c;
  Condition.signal cn;
  Mutex.unlock m;
  x

let broadcast { lock = m; cond = c } =
  Mutex.lock m;
  Condition.broadcast c;
  Mutex.unlock m

let push { queue = q; lock = m; cond = c; release } x =
  if release then CErrors.anomaly(Pp.str
    "TQueue.push while being destroyed! Only 1 producer/destroyer allowed.");
  Mutex.lock m;
  PriorityQueue.push q x;
  Condition.broadcast c;
  Mutex.unlock m

let length { queue = q; lock = m } =
  Mutex.lock m;
  let n = PriorityQueue.length q in
  Mutex.unlock m;
  n

let clear { queue = q; lock = m; cond = c } =
  Mutex.lock m;
  PriorityQueue.clear q;
  Mutex.unlock m

let clear_saving { queue = q; lock = m; cond = c } f =
  Mutex.lock m;
  let saved = ref [] in
  while not (PriorityQueue.is_empty q) do
    let elem = PriorityQueue.pop q in
    match f elem with
    | Some x -> saved := x :: !saved
    | None -> ()
  done;
  Mutex.unlock m;
  List.rev !saved

let is_empty { queue = q } = PriorityQueue.is_empty q

let destroy tq =
  tq.release <- true;
  while tq.nwaiting > 0 do
    Mutex.lock tq.lock;
    Condition.broadcast tq.cond;
    Mutex.unlock tq.lock;
  done;
  tq.release <- false

let wait_until_n_are_waiting_and_queue_empty j tq =
  Mutex.lock tq.lock;
  while not (PriorityQueue.is_empty tq.queue) || tq.nwaiting < j do
    Condition.wait tq.cond_waiting tq.lock
  done;
  Mutex.unlock tq.lock

let wait_until_n_are_waiting_then_snapshot j tq =
  let l = ref [] in
  Mutex.lock tq.lock;
  while not (PriorityQueue.is_empty tq.queue) do
    l := PriorityQueue.pop tq.queue :: !l
  done;
  while tq.nwaiting < j do Condition.wait tq.cond_waiting tq.lock done;
  List.iter (PriorityQueue.push tq.queue) (List.rev !l);
  if !l <> [] then Condition.broadcast tq.cond;
  Mutex.unlock tq.lock;
  List.rev !l

let set_order tq rel =
  Mutex.lock tq.lock;
  PriorityQueue.set_rel rel tq.queue;
  Mutex.unlock tq.lock

¤ Dauer der Verarbeitung: 0.3 Sekunden (vorverarbeitet) ¤

Download des Quellennavigators
Download des sprechenden Kalenders
in der Quellcodebibliothek suchen

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.