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 // 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(); final codes = new Set(); 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; }