undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/util/concurrent/tck/CountedCompleter8Test.java

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+/*
+ * 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.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea and Martin Buchholz with assistance from
+ * members of JCP JSR-166 Expert Group and released to the public
+ * domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+import java.util.concurrent.CountedCompleter;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+import junit.framework.Test;
+import junit.framework.TestSuite;
+
+public class CountedCompleter8Test extends JSR166TestCase {
+
+    public static void main(String[] args) {
+        main(suite(), args);
+    }
+
+    public static Test suite() {
+        return new TestSuite(CountedCompleter8Test.class);
+    }
+
+    /** CountedCompleter class javadoc code sample, version 1. */
+    public static <E> void forEach1(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent); this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                if (hi - lo >= 2) {
+                    int mid = (lo + hi) >>> 1;
+                    // must set pending count before fork
+                    setPendingCount(2);
+                    new Task(this, mid, hi).fork(); // right child
+                    new Task(this, lo, mid).fork(); // left child
+                }
+                else if (hi > lo)
+                    action.accept(array[lo]);
+                tryComplete();
+            }
+        }
+        new Task(null, 0, array.length).invoke();
+    }
+
+    /** CountedCompleter class javadoc code sample, version 2. */
+    public static <E> void forEach2(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent); this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                if (hi - lo >= 2) {
+                    int mid = (lo + hi) >>> 1;
+                    setPendingCount(1); // looks off by one, but correct!
+                    new Task(this, mid, hi).fork(); // right child
+                    new Task(this, lo, mid).compute(); // direct invoke
+                } else {
+                    if (hi > lo)
+                        action.accept(array[lo]);
+                    tryComplete();
+                }
+            }
+        }
+        new Task(null, 0, array.length).invoke();
+    }
+
+    /** CountedCompleter class javadoc code sample, version 3. */
+    public static <E> void forEach3(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent); this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                int n = hi - lo;
+                for (; n >= 2; n /= 2) {
+                    addToPendingCount(1);
+                    new Task(this, lo + n/2, lo + n).fork();
+                }
+                if (n > 0)
+                    action.accept(array[lo]);
+                propagateCompletion();
+            }
+        }
+        new Task(null, 0, array.length).invoke();
+    }
+
+    /** CountedCompleter class javadoc code sample, version 4. */
+    public static <E> void forEach4(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent, 31 - Integer.numberOfLeadingZeros(hi - lo));
+                this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                for (int n = hi - lo; n >= 2; n /= 2)
+                    new Task(this, lo + n/2, lo + n).fork();
+                action.accept(array[lo]);
+                propagateCompletion();
+            }
+        }
+        if (array.length > 0)
+            new Task(null, 0, array.length).invoke();
+    }
+
+    void testRecursiveDecomposition(
+        BiConsumer<Integer[], Consumer<Integer>> action) {
+        int n = ThreadLocalRandom.current().nextInt(8);
+        Integer[] a = new Integer[n];
+        for (int i = 0; i < n; i++) a[i] = i + 1;
+        AtomicInteger ai = new AtomicInteger(0);
+        action.accept(a, ai::addAndGet);
+        assertEquals(n * (n + 1) / 2, ai.get());
+    }
+
+    /**
+     * Variants of divide-by-two recursive decomposition into leaf tasks,
+     * as described in the CountedCompleter class javadoc code samples
+     */
+    public void testRecursiveDecomposition() {
+        testRecursiveDecomposition(CountedCompleter8Test::forEach1);
+        testRecursiveDecomposition(CountedCompleter8Test::forEach2);
+        testRecursiveDecomposition(CountedCompleter8Test::forEach3);
+        testRecursiveDecomposition(CountedCompleter8Test::forEach4);
+    }
+
+}