ceil/floor/truncate/round return integers.

tests/corelib/double_truncate_test.dart

+// Copyright (c) 2013, 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.
+
+main() {
+  Expect.equals(0, 0.0.truncate());
+  Expect.equals(0, double.MIN_POSITIVE.truncate());
+  Expect.equals(0, (2.0 * double.MIN_POSITIVE).truncate());
+  Expect.equals(0, (1.18e-38).truncate());
+  Expect.equals(0, (1.18e-38 * 2).truncate());
+  Expect.equals(0, 0.49999999999999994.truncate());
+  Expect.equals(0, 0.5.truncate());
+  Expect.equals(0, 0.9999999999999999.truncate());
+  Expect.equals(1, 1.0.truncate());
+  Expect.equals(1, 1.000000000000001.truncate());
+  // The following numbers are on the border of 52 bits.
+  // For example: 4503599627370499 + 0.5 => 4503599627370500.
+  Expect.equals(4503599627370496, 4503599627370496.0.truncate());
+  Expect.equals(4503599627370497, 4503599627370497.0.truncate());
+  Expect.equals(4503599627370498, 4503599627370498.0.truncate());
+  Expect.equals(4503599627370499, 4503599627370499.0.truncate());
+
+  Expect.equals(9007199254740991, 9007199254740991.0.truncate());
+  Expect.equals(9007199254740992, 9007199254740992.0.truncate());
+  Expect.equals(179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368,
+                double.MAX_FINITE.truncate());
+
+  Expect.equals(0, (-double.MIN_POSITIVE).truncate());
+  Expect.equals(0, (2.0 * -double.MIN_POSITIVE).truncate());
+  Expect.equals(0, (-1.18e-38).truncate());
+  Expect.equals(0, (-1.18e-38 * 2).truncate());
+  Expect.equals(0, (-0.49999999999999994).truncate());
+  Expect.equals(0, (-0.5).truncate());
+  Expect.equals(0, (-0.9999999999999999).truncate());
+  Expect.equals(-1, (-1.0).truncate());
+  Expect.equals(-1, (-1.000000000000001).truncate());
+  Expect.equals(-4503599627370496, (-4503599627370496.0).truncate());
+  Expect.equals(-4503599627370497, (-4503599627370497.0).truncate());
+  Expect.equals(-4503599627370498, (-4503599627370498.0).truncate());
+  Expect.equals(-4503599627370499, (-4503599627370499.0).truncate());
+  Expect.equals(-9007199254740991, (-9007199254740991.0).truncate());
+  Expect.equals(-9007199254740992, (-9007199254740992.0).truncate());
+  Expect.equals(-179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368,
+                (-double.MAX_FINITE).truncate());
+
+  Expect.isTrue(0.0.truncate() is int);
+  Expect.isTrue(double.MIN_POSITIVE.truncate() is int);
+  Expect.isTrue((2.0 * double.MIN_POSITIVE).truncate() is int);
+  Expect.isTrue((1.18e-38).truncate() is int);
+  Expect.isTrue((1.18e-38 * 2).truncate() is int);
+  Expect.isTrue(0.49999999999999994.truncate() is int);
+  Expect.isTrue(0.5.truncate() is int);
+  Expect.isTrue(0.9999999999999999.truncate() is int);
+  Expect.isTrue(1.0.truncate() is int);
+  Expect.isTrue(1.000000000000001.truncate() is int);
+  Expect.isTrue(4503599627370496.0.truncate() is int);
+  Expect.isTrue(4503599627370497.0.truncate() is int);
+  Expect.isTrue(4503599627370498.0.truncate() is int);
+  Expect.isTrue(4503599627370499.0.truncate() is int);
+  Expect.isTrue(9007199254740991.0.truncate() is int);
+  Expect.isTrue(9007199254740992.0.truncate() is int);
+  Expect.isTrue(double.MAX_FINITE.truncate() is int);
+
+  Expect.isTrue((-double.MIN_POSITIVE).truncateToDouble().isNegative);
+  Expect.isTrue((2.0 * -double.MIN_POSITIVE).truncateToDouble().isNegative);
+  Expect.isTrue((-1.18e-38).truncateToDouble().isNegative);
+  Expect.isTrue((-1.18e-38 * 2).truncateToDouble().isNegative);
+  Expect.isTrue((-0.49999999999999994).truncateToDouble().isNegative);
+  Expect.isTrue((-0.5).truncateToDouble().isNegative);
+  Expect.isTrue((-0.9999999999999999).truncateToDouble().isNegative);
+
+  Expect.isTrue((-double.MIN_POSITIVE).truncate() is int);
+  Expect.isTrue((2.0 * -double.MIN_POSITIVE).truncate() is int);
+  Expect.isTrue((-1.18e-38).truncate() is int);
+  Expect.isTrue((-1.18e-38 * 2).truncate() is int);
+  Expect.isTrue((-0.49999999999999994).truncate() is int);
+  Expect.isTrue((-0.5).truncate() is int);
+  Expect.isTrue((-0.9999999999999999).truncate() is int);
+  Expect.isTrue((-1.0).truncate() is int);
+  Expect.isTrue((-1.000000000000001).truncate() is int);
+  Expect.isTrue((-4503599627370496.0).truncate() is int);
+  Expect.isTrue((-4503599627370497.0).truncate() is int);
+  Expect.isTrue((-4503599627370498.0).truncate() is int);
+  Expect.isTrue((-4503599627370499.0).truncate() is int);
+  Expect.isTrue((-9007199254740991.0).truncate() is int);
+  Expect.isTrue((-9007199254740992.0).truncate() is int);
+  Expect.isTrue((-double.MAX_FINITE).truncate() is int);
+}