(*                        Reactive Asco                        *)
(*             http://reactiveml.org/reactive_asco             *)
(*                                                             *)
(*                                                             *)
(*  Authors: Guillaume Baudart (guillaume.baudart@ens.fr)      *)
(*           Louis Mandel (louis.mandel@lri.fr)                *)
(*                                                             *)

(** Implement the [wait] process (relative to the tempo). This is an
    optimized version using a priority queue.

open Types
open Utils

(** Generate a regular real-time signal [clock] of frequency [freq]. *) let process emit_clock clock freq = let period = 1. /. freq in let start = Unix.gettimeofday () in let cpt = ref 1 in let next = ref (start +. period) in loop let current = Unix.gettimeofday () in if (current >= !next) then begin emit clock (); cpt := !cpt + 1; next := start +. (float !cpt) *. period end; pause end

(** Compute the delay, relative to the tempo, elapsed since the beginning of its execution. The signal [listen] carries the estimation of the tempo. The signal [clock] is a signal present at a frequency [freq]. And [date] is the output signal. *) let process elapsed listen clock freq date = let period = 1. /. freq in let m = ref 0.0 in let c = ref 0.0 in emit date 0.0; do (* use Kahan summation *) loop let ev = last_one listen in let y = ev.bps -. !c in let t = !m +. y in c := (t -. !m) -. y; m := t; emit date (!m *. period); pause end when clock done
(* Run the processes [emit_clock] and [elapsed] and return [date]. *) let process metronome listen freq date = signal clock in run (emit_clock clock freq) || run (elapsed listen clock freq date)

(** Wait a delay [dur] relatively to the tempo. The waiting process is realized by the scheduler. Therefore to achieve the desired behavior we just need to register on the scheduler queue with the [adding] signal. The signal [date] carries the current date relative to the tempo. *) let process wait date adding dur = signal s in await immediate one date(e) in emit adding (dur +. e, s); await immediate s
(** Create a pair of processes [(scheduler, wait)]. The process [wait] suspends the execution for a duration [dur] relative to the tempo given by the signal [date]. The process [scheduler] manages the waiting. *) let make_action_scheduler date = signal adding in let sending d sl = List.iter (fun (_, s) -> emit s) sl in let wait = wait date adding in signal deadline in let rec process deadline_generator pre_d = await immediate one date (d) in emit deadline (d +. (d -. pre_d) /. 2.); pause; run (deadline_generator d) in let process action_scheduler = run (Reactive_queue.scheduler deadline sending adding) || run (deadline_generator 0.0) in action_scheduler, wait