Florian Loitsch
354a4ec420
Change-Id: I6529a9ac0ad6557dc751be5c6f7bf14c9d45f909 Reviewed-on: https://dart-review.googlesource.com/11400 Commit-Queue: Florian Loitsch <floitsch@google.com> Reviewed-by: Jakob Roland Andersen <jakobr@google.com>
28 lines
1.1 KiB
Dart
28 lines
1.1 KiB
Dart
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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/// Test of a common rounding bug.
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///
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/// This bug is common in JavaScript implementations because the ECMA-262
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/// specification of JavaScript incorrectly claims:
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///
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/// The value of [:Math.round(x):] is the same as the value of
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/// [:Math.floor(x+0.5):], except when x is 0 or is less than 0 but greater
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/// than or equal to -0.5; for these cases [:Math.round(x):] returns 0, but
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/// [:Math.floor(x+0.5):] returns +0.
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///
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/// However, 0.49999999999999994 + 0.5 is 1 and 9007199254740991 + 0.5 is
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/// 9007199254740992, so you cannot implement Math.round in terms of
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/// Math.floor.
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import 'package:expect/expect.dart';
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main() {
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Expect.equals(0, (0.49999999999999994).round());
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Expect.equals(0, (-0.49999999999999994).round());
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Expect.equals(9007199254740991, (9007199254740991.0).round());
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Expect.equals(-9007199254740991, (-9007199254740991.0).round());
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}
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