diff --git a/src/java.base/share/classes/java/util/Collections.java b/src/java.base/share/classes/java/util/Collections.java index f45d297f300..63949db2cc0 100644 --- a/src/java.base/share/classes/java/util/Collections.java +++ b/src/java.base/share/classes/java/util/Collections.java @@ -816,15 +816,16 @@ public class Collections { if (distance == 0) return; - for (int cycleStart = 0, nMoved = 0; nMoved != size; cycleStart++) { + int bound = size - distance; + for (int cycleStart = 0, nMoved = 0; nMoved < size; cycleStart++) { T displaced = list.get(cycleStart); int i = cycleStart; do { - i += distance; - if (i >= size) + if (i >= bound) i -= size; + i += distance; displaced = list.set(i, displaced); - nMoved ++; + nMoved++; } while (i != cycleStart); } } diff --git a/test/jdk/java/util/Collections/RotateHuge.java b/test/jdk/java/util/Collections/RotateHuge.java new file mode 100644 index 00000000000..44368aff266 --- /dev/null +++ b/test/jdk/java/util/Collections/RotateHuge.java @@ -0,0 +1,83 @@ +/* + * Copyright (c) 2023, 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. + */ + +/* + * @test + * @bug 8314236 + * @summary Overflow in Collections.rotate + */ + +import java.util.AbstractList; +import java.util.Collections; +import java.util.List; +import java.util.Objects; +import java.util.RandomAccess; + +public class RotateHuge { + + private static final class MockList extends AbstractList + implements RandomAccess { + private final int size; + + public MockList(final int size) { + if (size < 0) + throw new IllegalArgumentException("Illegal size: " + size); + this.size = size; + } + + @Override + public Object get(final int index) { + Objects.checkIndex(index, size); + return null; + } + + @Override + public Object set(final int index, final Object element) { + Objects.checkIndex(index, size); + return null; + } + + @Override + public int size() { + return size; + } + } + + public static void main(final String[] args) { + testRotate((1 << 30) + 1, -(1 << 30) - 2); + testRotate((1 << 30) + 1, 1 << 30); + testRotate(Integer.MAX_VALUE, Integer.MIN_VALUE); + testRotate(Integer.MAX_VALUE, Integer.MIN_VALUE + 3); + testRotate(Integer.MAX_VALUE, 2); + testRotate(Integer.MAX_VALUE, Integer.MAX_VALUE - 1); + } + + /* + * This test covers only index computations. + * Correctness of elements rotation is not checked. + */ + private static void testRotate(final int size, final int distance) { + final List list = new MockList(size); + Collections.rotate(list, distance); + } +}