mirror of
https://github.com/dart-lang/sdk
synced 2024-11-02 15:01:30 +00:00
35da19ac07
Change-Id: I0e97add738bc79314a210cf137525b7391467fc2 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152595 Reviewed-by: Siva Annamalai <asiva@google.com> Commit-Queue: Bob Nystrom <rnystrom@google.com> Auto-Submit: Bob Nystrom <rnystrom@google.com>
48 lines
1.4 KiB
Dart
48 lines
1.4 KiB
Dart
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
// Test that the distribution of hash codes for doubles is reasonable.
|
|
|
|
// VMOptions=--intrinsify
|
|
// VMOptions=--no_intrinsify
|
|
|
|
import 'package:expect/expect.dart';
|
|
|
|
main() {
|
|
Expect.isTrue(ratio(0, 1) >= 0.95);
|
|
Expect.isTrue(ratio(0, 100) >= 0.95);
|
|
Expect.isTrue(ratio(0, 0xffffff) >= 0.95);
|
|
Expect.isTrue(ratio(0xffffff) >= 0.95);
|
|
Expect.isTrue(ratio(0xffffffff) >= 0.95);
|
|
Expect.isTrue(ratio(0xffffffffffffff) >= 0.95);
|
|
|
|
Expect.isTrue(ratio(0, -1) >= 0.95);
|
|
Expect.isTrue(ratio(0, -100) >= 0.95);
|
|
Expect.isTrue(ratio(0, -0xffffff) >= 0.95);
|
|
Expect.isTrue(ratio(-0xffffff) >= 0.95);
|
|
Expect.isTrue(ratio(-0xffffffff) >= 0.95);
|
|
Expect.isTrue(ratio(-0xffffffffffffff) >= 0.95);
|
|
}
|
|
|
|
double ratio(num start, [num? end]) {
|
|
final n = 1000;
|
|
end ??= (start + 1) * 2;
|
|
|
|
// Collect the set of distinct doubles and the
|
|
// set of distinct hash codes.
|
|
final doubles = new Set<double>();
|
|
final codes = new Set<int>();
|
|
|
|
final step = (end.toDouble() - start.toDouble()) / n;
|
|
var current = start.toDouble();
|
|
for (int i = 0; i < n; i++) {
|
|
doubles.add(current);
|
|
codes.add(current.hashCode);
|
|
current += step;
|
|
}
|
|
|
|
// Return the ratio between distinct doubles and
|
|
// distinct hash codes.
|
|
return codes.length / doubles.length;
|
|
}
|