test/jdk/java/math/BigInteger/PrimitiveConversionTests.java
changeset 47216 71c04702a3d5
parent 18538 642cc17315fd
child 52789 a051c5c8aa56
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/math/BigInteger/PrimitiveConversionTests.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import static java.math.BigInteger.ONE;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+
+/**
+ * @test
+ * @bug 7131192
+ * @summary This test ensures that BigInteger.floatValue() and
+ *          BigInteger.doubleValue() behave correctly.
+ * @author Louis Wasserman
+ */
+public class PrimitiveConversionTests {
+    static final List<BigInteger> ALL_BIGINTEGER_CANDIDATES;
+
+    static {
+        List<BigInteger> samples = new ArrayList<>();
+        // Now add values near 2^N for lots of values of N.
+        for (int exponent : Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 31, 32, 33,
+                34, 62, 63, 64, 65, 71, 72, 73, 79, 80, 81, 255, 256, 257, 511,
+                512, 513, Double.MAX_EXPONENT - 1, Double.MAX_EXPONENT,
+                Double.MAX_EXPONENT + 1, 2000, 2001, 2002)) {
+            BigInteger x = ONE.shiftLeft(exponent);
+            for (BigInteger y : Arrays.asList(x, x.add(ONE), x.subtract(ONE))) {
+                samples.add(y);
+                samples.add(y.negate());
+            }
+        }
+
+        Random rng = new Random(1234567);
+        for (int i = 0; i < 2000; i++) {
+            samples.add(new BigInteger(rng.nextInt(2000), rng));
+        }
+
+        ALL_BIGINTEGER_CANDIDATES = Collections.unmodifiableList(samples);
+    }
+
+    public static int testDoubleValue() {
+        int failures = 0;
+        for (BigInteger big : ALL_BIGINTEGER_CANDIDATES) {
+            double expected = Double.parseDouble(big.toString());
+            double actual = big.doubleValue();
+
+            // should be bitwise identical
+            if (Double.doubleToRawLongBits(expected) != Double
+                    .doubleToRawLongBits(actual)) {
+                System.out.println(big);
+                failures++;
+            }
+        }
+        return failures;
+    }
+
+    public static int testFloatValue() {
+        int failures = 0;
+        for (BigInteger big : ALL_BIGINTEGER_CANDIDATES) {
+            float expected = Float.parseFloat(big.toString());
+            float actual = big.floatValue();
+
+            // should be bitwise identical
+            if (Float.floatToRawIntBits(expected) != Float
+                    .floatToRawIntBits(actual)) {
+                System.out.println(big + " " + expected + " " + actual);
+                failures++;
+            }
+        }
+        return failures;
+    }
+
+    public static void main(String[] args) {
+        int failures = testDoubleValue();
+        failures += testFloatValue();
+        if (failures > 0) {
+            throw new RuntimeException("Incurred " + failures
+                    + " failures while testing primitive conversions.");
+        }
+    }
+}