49 lines
No EOL
1.4 KiB
HTML
49 lines
No EOL
1.4 KiB
HTML
<!DOCTYPE html>
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<script src="/resources/testharness.js"></script>
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<script src="/resources/testharnessreport.js"></script>
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<script type="text/javascript">
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'use strict';
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// Computes greatest common divisor of a and b using Euclid's algorithm
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function computeGCD(a, b) {
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if (!Number.isInteger(a) || !Number.isInteger(b)) {
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throw new Error('Parameters must be integer numbers');
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}
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var r;
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while (b != 0) {
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r = a % b;
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a = b;
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b = r;
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}
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return (a < 0) ? -a : a;
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}
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// Finds minimum resolution Δ given a set of samples which are known to be in the form of N*Δ.
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// We use GCD of all samples as a simple estimator.
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function estimateMinimumResolution(samples) {
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var gcd;
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for (const sample of samples) {
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gcd = gcd ? computeGCD(gcd, sample) : sample;
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}
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return gcd;
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}
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test(function() {
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const samples = [];
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for (var i = 0; i < 1e3; i++) {
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var deltaInMicroSeconds = 0;
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const e1 = new MouseEvent('test1');
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do {
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const e2 = new MouseEvent('test2');
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deltaInMicroSeconds = Math.round((e2.timeStamp - e1.timeStamp) * 1000);
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} while (deltaInMicroSeconds == 0) // only collect non-zero samples
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samples.push(deltaInMicroSeconds);
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}
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const minResolution = estimateMinimumResolution(samples);
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assert_greater_than_equal(minResolution, 5);
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}, 'Event timestamp should not have a resolution better than 5 microseconds');
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</script> |