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 // |reftest| skip

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 //-----------------------------------------------------------------------

 var summary = "Lamport Bakery's algorithm for mutual exclusion";

 // Adapted from pseudocode in Wikipedia:

 // http://en.wikipedia.org/wiki/Lamport%27s_bakery_algorithm

 printStatus(summary);

 var N = 15; // Number of threads.

 var LOOP_COUNT = 10; // Number of times each thread should loop

 function range(n) {

   for (let i = 0; i < n; i++)

     yield i;

 }

 function max(a) {

   let x = Number.NEGATIVE_INFINITY;

   for each (let i in a)

     if (i > x)

       x = i;

   return x;

 }

 // the mutex mechanism

 var entering = [false for (i in range(N))];

 var ticket = [0 for (i in range(N))];

 // the object being protected

 var counter = 0;

 function lock(i)

 {

   entering[i] = true;

   ticket[i] = 1 + max(ticket);

   entering[i] = false;

   for (let j = 0; j < N; j++) {

     // If thread j is in the middle of getting a ticket, wait for that to

     // finish.

     while (entering[j])

       ;

     // Wait until all threads with smaller ticket numbers or with the same

     // ticket number, but with higher priority, finish their work.

     while ((ticket[j] != 0) && ((ticket[j] < ticket[i]) ||

                                 ((ticket[j] == ticket[i]) && (i < j))))

       ;

   }

 }

 function unlock(i) {

   ticket[i] = 0;

 }

 function worker(i) {

   for (let k = 0; k < LOOP_COUNT; k++) {

     lock(i);

     // The critical section

     let x = counter;

     sleep(0.003);

     counter = x + 1;

     unlock(i);

   }

   return 'ok';

 }

 function makeWorker(id) {

   return function () { return worker(id); };

 }

 var expect;

 var actual;

 if (typeof scatter == 'undefined' || typeof sleep == 'undefined') {

   print('Test skipped. scatter or sleep not defined.');

   expect = actual = 'Test skipped.';

 } else {

   scatter([makeWorker(i) for (i in range(N))]);

   expect = "counter: " + (N * LOOP_COUNT);

   actual = "counter: " + counter;

 }

 reportCompare(expect, actual, summary);