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      1 // Copyright 2016 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 
      6 new BenchmarkSuite('Generators', [1000], [
      7   new Benchmark('Basic', false, false, 0, Basic),
      8   new Benchmark('Loop', false, false, 0, Loop),
      9   new Benchmark('Input', false, false, 0, Input),
     10   new Benchmark('YieldStar', false, false, 0, YieldStar),
     11 ]);
     12 
     13 
     14 // ----------------------------------------------------------------------------
     15 // Benchmark: Basic
     16 // ----------------------------------------------------------------------------
     17 
     18 function* five() {
     19   yield 1;
     20   yield 2;
     21   yield 3;
     22   yield 4;
     23   yield 5;
     24 }
     25 
     26 function Basic() {
     27   let g = five();
     28   let sum = 0;
     29   sum += g.next().value;
     30   sum += g.next().value;
     31   sum += g.next().value;
     32   sum += g.next().value;
     33   sum += g.next().value;
     34   if (sum != 15 || !g.next().done) throw "wrong";
     35 }
     36 
     37 
     38 // ----------------------------------------------------------------------------
     39 // Benchmark: Loop
     40 // ----------------------------------------------------------------------------
     41 
     42 function* fibonacci() {
     43   let x = 0;
     44   let y = 1;
     45   yield x;
     46   while (true) {
     47     yield y;
     48     let tmp = x;
     49     x = y;
     50     y += tmp;
     51   }
     52 }
     53 
     54 function Loop() {
     55   let n = 0;
     56   let x;
     57   for (x of fibonacci()) {
     58     if (++n === 42) break;
     59   }
     60   if (x != 165580141) throw "wrong";
     61 }
     62 
     63 
     64 
     65 // ----------------------------------------------------------------------------
     66 // Benchmark: Input
     67 // ----------------------------------------------------------------------------
     68 
     69 function* multiples(x) {
     70   let skip = function.sent || 0;
     71   let next = 0;
     72   while (true) {
     73     if (skip === 0) {
     74       skip = yield next;
     75     } else {
     76       skip--;
     77     }
     78     next += x;
     79   }
     80 }
     81 
     82 function Input() {
     83   let g = multiples(3);
     84   results = [g.next(2), g.next(0), g.next(5), g.next(10)];
     85   if (results.slice(-1)[0].value != 60) throw "wrong";
     86 }
     87 
     88 
     89 // ----------------------------------------------------------------------------
     90 // Benchmark: YieldStar
     91 // ----------------------------------------------------------------------------
     92 
     93 function* infix(node) {
     94   if (node) {
     95     yield* infix(node.left);
     96     yield node.label;
     97     yield* infix(node.right);
     98   }
     99 }
    100 
    101 class Node {
    102   constructor(label, left, right) {
    103     this.label = label;
    104     this.left = left;
    105     this.right = right;
    106   }
    107 }
    108 
    109 function YieldStar() {
    110   let tree = new Node(1,
    111       new Node(2,
    112           new Node(3,
    113               new Node(4,
    114                   new Node(16,
    115                       new Node(5,
    116                           new Node(23,
    117                               new Node(0),
    118                               new Node(17)),
    119                           new Node(44, new Node(20)))),
    120                   new Node(7,
    121                       undefined,
    122                       new Node(23,
    123                           new Node(0),
    124                           new Node(41, undefined, new Node(11))))),
    125               new Node(8)),
    126           new Node(5)),
    127       new Node(6, undefined, new Node(7)));
    128   let labels = [...(infix(tree))];
    129   // 0,23,17,5,20,44,16,4,7,0,23,41,11,3,8,2,5,1,6,7
    130   if (labels[0] != 0) throw "wrong";
    131 }
    132