--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/jdk/internal/misc/Unsafe/CopySwap.java Wed Feb 10 19:55:57 2016 -0800
@@ -0,0 +1,711 @@
+/*
+ * Copyright (c) 2016, 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 jdk.internal.misc.Unsafe;
+import java.lang.reflect.Field;
+
+/*
+ * @test
+ * @summary Test Unsafe.copySwapMemory
+ * @modules java.base/jdk.internal.misc
+ */
+public class CopySwap {
+ private static final boolean DEBUG = Boolean.getBoolean("CopySwap.DEBUG");
+
+ public static final long KB = 1024;
+ public static final long MB = KB * 1024;
+ public static final long GB = MB * 1024;
+
+ private static final Unsafe UNSAFE;
+ private static final int SMALL_COPY_SIZE = 32;
+ private static final int BASE_ALIGNMENT = 16;
+
+ static {
+ try {
+ Field f = jdk.internal.misc.Unsafe.class.getDeclaredField("theUnsafe");
+ f.setAccessible(true);
+ UNSAFE = (jdk.internal.misc.Unsafe) f.get(null);
+ } catch (Exception e) {
+ throw new RuntimeException("Unable to get Unsafe instance.", e);
+ }
+ }
+
+ private static long alignDown(long value, long alignment) {
+ return value & ~(alignment - 1);
+ }
+
+ private static long alignUp(long value, long alignment) {
+ return (value + alignment - 1) & ~(alignment - 1);
+ }
+
+ private static boolean isAligned(long value, long alignment) {
+ return value == alignDown(value, alignment);
+ }
+
+ private CopySwap() {
+ }
+
+ /**
+ * Generate verification data for a given offset
+ *
+ * The verification data is used to verify that the correct bytes
+ * have indeed been copied and byte swapped.
+ *
+ * The data is generated based on the offset (in bytes) into the
+ * source buffer. For a native buffer the offset is relative to
+ * the base pointer. For a heap array it is relative to the
+ * address of the first array element.
+ *
+ * This method will return the result of doing an elementSize byte
+ * read starting at offset (in bytes).
+ *
+ * @param offset offset into buffer
+ * @param elemSize size (in bytes) of the element
+ *
+ * @return the verification data, only the least significant
+ * elemSize*8 bits are set, zero extended
+ */
+ private long getVerificationDataForOffset(long offset, long elemSize) {
+ byte[] bytes = new byte[(int)elemSize];
+
+ for (long i = 0; i < elemSize; i++) {
+ bytes[(int)i] = (byte)(offset + i);
+ }
+
+ long o = UNSAFE.arrayBaseOffset(byte[].class);
+
+ switch ((int)elemSize) {
+ case 1: return Byte.toUnsignedLong(UNSAFE.getByte(bytes, o));
+ case 2: return Short.toUnsignedLong(UNSAFE.getShortUnaligned(bytes, o));
+ case 4: return Integer.toUnsignedLong(UNSAFE.getIntUnaligned(bytes, o));
+ case 8: return UNSAFE.getLongUnaligned(bytes, o);
+ default: throw new IllegalArgumentException("Invalid element size: " + elemSize);
+ }
+ }
+
+ /**
+ * Verify byte swapped data
+ *
+ * @param ptr the data to verify
+ * @param srcOffset the srcOffset (in bytes) from which the copy started,
+ * used as key to regenerate the verification data
+ * @param dstOffset the offset (in bytes) in the array at which to start
+ * the verification, relative to the first element in the array
+ * @param size size (in bytes) of data to to verify
+ * @param elemSize size (in bytes) of the individual array elements
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void verifySwappedData(GenericPointer ptr, long srcOffset, long dstOffset, long size, long elemSize) {
+ for (long offset = 0; offset < size; offset += elemSize) {
+ long expectedUnswapped = getVerificationDataForOffset(srcOffset + offset, elemSize);
+ long expected = byteSwap(expectedUnswapped, elemSize);
+
+ long actual = getArrayElem(ptr, dstOffset + offset, elemSize);
+
+ if (expected != actual) {
+ throw new RuntimeException("srcOffset: 0x" + Long.toHexString(srcOffset) +
+ " dstOffset: 0x" + Long.toHexString(dstOffset) +
+ " size: 0x" + Long.toHexString(size) +
+ " offset: 0x" + Long.toHexString(offset) +
+ " expectedUnswapped: 0x" + Long.toHexString(expectedUnswapped) +
+ " expected: 0x" + Long.toHexString(expected) +
+ " != actual: 0x" + Long.toHexString(actual));
+ }
+ }
+ }
+
+ /**
+ * Initialize an array with verification friendly data
+ *
+ * @param ptr pointer to the data to initialize
+ * @param size size (in bytes) of the data
+ * @param elemSize size (in bytes) of the individual elements
+ */
+ private void initVerificationData(GenericPointer ptr, long size, long elemSize) {
+ for (long offset = 0; offset < size; offset++) {
+ byte data = (byte)getVerificationDataForOffset(offset, 1);
+
+ if (ptr.isOnHeap()) {
+ UNSAFE.putByte(ptr.getObject(), ptr.getOffset() + offset, data);
+ } else {
+ UNSAFE.putByte(ptr.getOffset() + offset, data);
+ }
+ }
+ }
+
+ /**
+ * Allocate a primitive array
+ *
+ * @param size size (in bytes) of all the array elements (elemSize * length)
+ * @param elemSize the size of the array elements
+ *
+ * @return a newly allocated primitive array
+ */
+ Object allocArray(long size, long elemSize) {
+ int length = (int)(size / elemSize);
+
+ switch ((int)elemSize) {
+ case 2: return new short[length];
+ case 4: return new int[length];
+ case 8: return new long[length];
+ default:
+ throw new IllegalArgumentException("Invalid element size: " + elemSize);
+ }
+ }
+
+ /**
+ * Get the value of a primitive array entry
+ *
+ * @param ptr pointer to the data
+ * @param offset offset (in bytes) of the array element, relative to the first element in the array
+ *
+ * @return the array element, as an unsigned long
+ */
+ private long getArrayElem(GenericPointer ptr, long offset, long elemSize) {
+ if (ptr.isOnHeap()) {
+ Object o = ptr.getObject();
+ int index = (int)(offset / elemSize);
+
+ if (o instanceof short[]) {
+ short[] arr = (short[])o;
+ return Short.toUnsignedLong(arr[index]);
+ } else if (o instanceof int[]) {
+ int[] arr = (int[])o;
+ return Integer.toUnsignedLong(arr[index]);
+ } else if (o instanceof long[]) {
+ long[] arr = (long[])o;
+ return arr[index];
+ } else {
+ throw new IllegalArgumentException("Invalid object type: " + o.getClass().getName());
+ }
+ } else {
+ long addr = ptr.getOffset() + offset;
+
+ switch ((int)elemSize) {
+ case 1: return Byte.toUnsignedLong(UNSAFE.getByte(addr));
+ case 2: return Short.toUnsignedLong(UNSAFE.getShortUnaligned(null, addr));
+ case 4: return Integer.toUnsignedLong(UNSAFE.getIntUnaligned(null, addr));
+ case 8: return UNSAFE.getLongUnaligned(null, addr);
+ default: throw new IllegalArgumentException("Invalid element size: " + elemSize);
+ }
+ }
+ }
+
+ private void putValue(long addr, long elemSize, long value) {
+ switch ((int)elemSize) {
+ case 1: UNSAFE.putByte(addr, (byte)value); break;
+ case 2: UNSAFE.putShortUnaligned(null, addr, (short)value); break;
+ case 4: UNSAFE.putIntUnaligned(null, addr, (int)value); break;
+ case 8: UNSAFE.putLongUnaligned(null, addr, value); break;
+ default: throw new IllegalArgumentException("Invalid element size: " + elemSize);
+ }
+ }
+
+ /**
+ * Get the size of the elements for an array
+ *
+ * @param o a primitive heap array
+ *
+ * @return the size (in bytes) of the individual array elements
+ */
+ private long getArrayElemSize(Object o) {
+ if (o instanceof short[]) {
+ return 2;
+ } else if (o instanceof int[]) {
+ return 4;
+ } else if (o instanceof long[]) {
+ return 8;
+ } else {
+ throw new IllegalArgumentException("Invalid object type: " + o.getClass().getName());
+ }
+ }
+
+ /**
+ * Byte swap a value
+ *
+ * @param value the value to swap, only the bytes*8 least significant bits are used
+ * @param size size (in bytes) of the value
+ *
+ * @return the byte swapped value in the bytes*8 least significant bits
+ */
+ private long byteSwap(long value, long size) {
+ switch ((int)size) {
+ case 2: return Short.toUnsignedLong(Short.reverseBytes((short)value));
+ case 4: return Integer.toUnsignedLong(Integer.reverseBytes((int)value));
+ case 8: return Long.reverseBytes(value);
+ default: throw new IllegalArgumentException("Invalid element size: " + size);
+ }
+ }
+
+ /**
+ * Verify data in a heap array which has *not* been byte swapped
+ *
+ * @param ptr the data to verify
+ * @param startOffset the offset (in bytes) at which to start the verification
+ * @param size size (in bytes) of the data to verify
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void verifyUnswappedData(GenericPointer ptr, long startOffset, long size) {
+ for (long elemOffset = startOffset; elemOffset < startOffset + size; elemOffset++) {
+ byte expected = (byte)getVerificationDataForOffset(elemOffset, 1);
+
+ byte actual;
+ if (ptr.isOnHeap()) {
+ actual = UNSAFE.getByte(ptr.getObject(), ptr.getOffset() + elemOffset);
+ } else {
+ actual = UNSAFE.getByte(ptr.getOffset() + elemOffset);
+ }
+
+ if (expected != actual) {
+ throw new RuntimeException("startOffset: 0x" + Long.toHexString(startOffset) +
+ " size: 0x" + Long.toHexString(size) +
+ " elemOffset: 0x" + Long.toHexString(elemOffset) +
+ " expected: 0x" + Long.toHexString(expected) +
+ " != actual: 0x" + Long.toHexString(actual));
+ }
+ }
+ }
+
+
+ /**
+ * Copy and byte swap data from the source to the destination
+ *
+ * This method will pre-populate the whole source and destination
+ * buffers with verification friendly data. It will then use
+ * copySwapMemory to fill part of the destination buffer with
+ * swapped data from the source. Some space (padding) will be
+ * left before and after the data in the destination buffer, which
+ * should not be touched/overwritten by the copy call.
+ *
+ * Note: Both source and destination buffers will be overwritten!
+ *
+ * @param src source buffer to copy from
+ * @param srcOffset the offset (in bytes) in the source buffer, relative to
+ * the first array element, at which to start reading data
+ * @param dst destination buffer to copy to
+ * @param dstOffset the offset (in bytes) in the destination
+ * buffer, relative to the first array element, at which to
+ * start writing data
+ * @param bufSize the size (in bytes) of the src and dst arrays
+ * @param copyBytes the size (in bytes) of the copy to perform,
+ * must be a multiple of elemSize
+ * @param elemSize the size (in bytes) of the elements to byte swap
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void testCopySwap(GenericPointer src, long srcOffset,
+ GenericPointer dst, long dstOffset,
+ long bufSize, long copyBytes, long elemSize) {
+ if (!isAligned(copyBytes, elemSize)) {
+ throw new IllegalArgumentException(
+ "copyBytes (" + copyBytes + ") must be a multiple of elemSize (" + elemSize + ")");
+ }
+ if (src.isOnHeap() && !isAligned(srcOffset, elemSize)) {
+ throw new IllegalArgumentException(
+ "srcOffset (" + srcOffset + ") must be a multiple of elemSize (" + elemSize + ")");
+ }
+ if (dst.isOnHeap() && !isAligned(dstOffset, elemSize)) {
+ throw new IllegalArgumentException(
+ "dstOffset (" + dstOffset + ") must be a multiple of elemSize (" + elemSize + ")");
+ }
+ if (srcOffset + copyBytes > bufSize) {
+ throw new IllegalArgumentException(
+ "srcOffset (" + srcOffset + ") + copyBytes (" + copyBytes + ") > bufSize (" + bufSize + ")");
+ }
+ if (dstOffset + copyBytes > bufSize) {
+ throw new IllegalArgumentException(
+ "dstOffset (" + dstOffset + ") + copyBytes (" + copyBytes + ") > bufSize (" + bufSize + ")");
+ }
+
+ // Initialize the whole source buffer with a verification friendly pattern (no 0x00 bytes)
+ initVerificationData(src, bufSize, elemSize);
+ if (!src.equals(dst)) {
+ initVerificationData(dst, bufSize, elemSize);
+ }
+
+ if (DEBUG) {
+ System.out.println("===before===");
+ for (int offset = 0; offset < bufSize; offset += elemSize) {
+ long srcValue = getArrayElem(src, offset, elemSize);
+ long dstValue = getArrayElem(dst, offset, elemSize);
+
+ System.out.println("offs=0x" + Long.toHexString(Integer.toUnsignedLong(offset)) +
+ " src=0x" + Long.toHexString(srcValue) +
+ " dst=0x" + Long.toHexString(dstValue));
+ }
+ }
+
+ // Copy & swap data into the middle of the destination buffer
+ UNSAFE.copySwapMemory(src.getObject(),
+ src.getOffset() + srcOffset,
+ dst.getObject(),
+ dst.getOffset() + dstOffset,
+ copyBytes,
+ elemSize);
+
+ if (DEBUG) {
+ System.out.println("===after===");
+ for (int offset = 0; offset < bufSize; offset += elemSize) {
+ long srcValue = getArrayElem(src, offset, elemSize);
+ long dstValue = getArrayElem(dst, offset, elemSize);
+
+ System.out.println("offs=0x" + Long.toHexString(Integer.toUnsignedLong(offset)) +
+ " src=0x" + Long.toHexString(srcValue) +
+ " dst=0x" + Long.toHexString(dstValue));
+ }
+ }
+
+ // Verify the the front padding is unchanged
+ verifyUnswappedData(dst, 0, dstOffset);
+
+ // Verify swapped data
+ verifySwappedData(dst, srcOffset, dstOffset, copyBytes, elemSize);
+
+ // Verify that the back back padding is unchanged
+ long frontAndDataBytes = dstOffset + copyBytes;
+ long trailingBytes = bufSize - frontAndDataBytes;
+ verifyUnswappedData(dst, frontAndDataBytes, trailingBytes);
+ }
+
+ /**
+ * Test various configurations copy-swapping from one buffer to the other
+ *
+ * @param src the source buffer to copy from
+ * @param dst the destination buffer to copy to
+ * @param size size (in bytes) of the buffers
+ * @param elemSize size (in bytes) of the individual elements
+ *
+ * @throws RuntimeException if an error is found
+ */
+ public void testBufferPair(GenericPointer src, GenericPointer dst, long size, long elemSize) {
+ // offset in source from which to start reading data
+ for (long srcOffset = 0; srcOffset < size; srcOffset += (src.isOnHeap() ? elemSize : 1)) {
+
+ // offset in destination at which to start writing data
+ for (int dstOffset = 0; dstOffset < size; dstOffset += (dst.isOnHeap() ? elemSize : 1)) {
+
+ // number of bytes to copy
+ long maxCopyBytes = Math.min(size - srcOffset, size - dstOffset);
+ for (long copyBytes = 0; copyBytes < maxCopyBytes; copyBytes += elemSize) {
+ try {
+ testCopySwap(src, srcOffset, dst, dstOffset, size, copyBytes, elemSize);
+ } catch (RuntimeException e) {
+ // Wrap the exception in another exception to catch the relevant configuration data
+ throw new RuntimeException("testBufferPair: " +
+ "src=" + src +
+ " dst=" + dst +
+ " elemSize=0x" + Long.toHexString(elemSize) +
+ " copyBytes=0x" + Long.toHexString(copyBytes) +
+ " srcOffset=0x" + Long.toHexString(srcOffset) +
+ " dstOffset=0x" + Long.toHexString(dstOffset),
+ e);
+ }
+ }
+ }
+ }
+ }
+
+ /**
+ * Test copying between various permutations of buffers
+ *
+ * @param buffers buffers to permute (src x dst)
+ * @param size size (in bytes) of buffers
+ * @param elemSize size (in bytes) of individual elements
+ *
+ * @throws RuntimeException if an error is found
+ */
+ public void testPermuteBuffers(GenericPointer[] buffers, long size, long elemSize) {
+ for (int srcIndex = 0; srcIndex < buffers.length; srcIndex++) {
+ for (int dstIndex = 0; dstIndex < buffers.length; dstIndex++) {
+ testBufferPair(buffers[srcIndex], buffers[dstIndex], size, elemSize);
+ }
+ }
+ }
+
+ /**
+ * Test copying of a specific element size
+ *
+ * @param size size (in bytes) of buffers to allocate
+ * @param elemSize size (in bytes) of individual elements
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void testElemSize(long size, long elemSize) {
+ long buf1Raw = 0;
+ long buf2Raw = 0;
+
+ try {
+ buf1Raw = UNSAFE.allocateMemory(size + BASE_ALIGNMENT);
+ long buf1 = alignUp(buf1Raw, BASE_ALIGNMENT);
+
+ buf2Raw = UNSAFE.allocateMemory(size + BASE_ALIGNMENT);
+ long buf2 = alignUp(buf2Raw, BASE_ALIGNMENT);
+
+ GenericPointer[] buffers = {
+ new GenericPointer(buf1),
+ new GenericPointer(buf2),
+ new GenericPointer(allocArray(size, elemSize)),
+ new GenericPointer(allocArray(size, elemSize))
+ };
+
+ testPermuteBuffers(buffers, size, elemSize);
+ } finally {
+ if (buf1Raw != 0) {
+ UNSAFE.freeMemory(buf1Raw);
+ }
+ if (buf2Raw != 0) {
+ UNSAFE.freeMemory(buf2Raw);
+ }
+ }
+ }
+
+ /**
+ * Verify that small copy swaps work
+ */
+ private void testSmallCopy() {
+ int smallBufSize = SMALL_COPY_SIZE;
+
+ // Test various element types and heap/native combinations
+ for (long elemSize = 2; elemSize <= 8; elemSize <<= 1) {
+ testElemSize(smallBufSize, elemSize);
+ }
+ }
+
+
+ /**
+ * Verify that large copy swaps work
+ */
+ private void testLargeCopy() {
+ long size = 2 * GB + 8;
+ long bufRaw = 0;
+
+ // Check that a large native copy succeeds
+ try {
+ try {
+ bufRaw = UNSAFE.allocateMemory(size + BASE_ALIGNMENT);
+ } catch (OutOfMemoryError e) {
+ // Accept failure, skip test
+ return;
+ }
+
+ long buf = alignUp(bufRaw, BASE_ALIGNMENT);
+
+ UNSAFE.copySwapMemory(null, buf, null, buf, size, 8);
+ } catch (Exception e) {
+ throw new RuntimeException("copySwapMemory of large buffer failed");
+ } finally {
+ if (bufRaw != 0) {
+ UNSAFE.freeMemory(bufRaw);
+ }
+ }
+ }
+
+ /**
+ * Run positive tests
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void testPositive() {
+ testSmallCopy();
+ testLargeCopy();
+ }
+
+ /**
+ * Run negative tests, testing corner cases and the various exceptions
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void testNegative() {
+ long bufRaw = 0;
+
+ try {
+ bufRaw = UNSAFE.allocateMemory(1024);
+ long buf = alignUp(bufRaw, BASE_ALIGNMENT);
+ short[] arr = new short[16];
+
+ // Check various illegal element sizes
+ for (int elemSize = 2; elemSize <= 8; elemSize <<= 1) {
+ long[] illegalSizes = { -1, 1, elemSize - 1, elemSize + 1, elemSize * 2 - 1 };
+ for (long size : illegalSizes) {
+ try {
+ // Check that illegal elemSize throws an IAE
+ UNSAFE.copySwapMemory(null, buf, null, buf, size, elemSize);
+ throw new RuntimeException("copySwapMemory failed to throw IAE for size=" + size + " elemSize=" + elemSize);
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+ }
+ }
+
+ try {
+ // Check that negative srcOffset throws an IAE
+ UNSAFE.copySwapMemory(arr, -1, arr, UNSAFE.arrayBaseOffset(arr.getClass()), 16, 2);
+ throw new RuntimeException("copySwapMemory failed to throw IAE for srcOffset=-1");
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+
+ try {
+ // Check that negative dstOffset throws an IAE
+ UNSAFE.copySwapMemory(arr, UNSAFE.arrayBaseOffset(arr.getClass()), arr, -1, 16, 2);
+ throw new RuntimeException("copySwapMemory failed to throw IAE for destOffset=-1");
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+
+ long illegalElemSizes[] = { 0, 1, 3, 5, 6, 7, 9, 10, -1 };
+ for (long elemSize : illegalElemSizes) {
+ try {
+ // Check that elemSize 1 throws an IAE
+ UNSAFE.copySwapMemory(null, buf, null, buf, 16, elemSize);
+ throw new RuntimeException("copySwapMemory failed to throw NPE");
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+ }
+
+ try {
+ // Check that a NULL source throws NPE
+ UNSAFE.copySwapMemory(null, 0, null, buf, 16, 2);
+ throw new RuntimeException("copySwapMemory failed to throw NPE");
+ } catch (NullPointerException e) {
+ // good
+ }
+
+ try {
+ // Check that a NULL destination throws NPE
+ UNSAFE.copySwapMemory(null, buf, null, 0, 16, 2);
+ throw new RuntimeException("copySwapMemory failed to throw NPE");
+ } catch (NullPointerException e) {
+ // good
+ }
+
+ try {
+ // Check that a reference array destination throws IAE
+ UNSAFE.copySwapMemory(null, buf, new Object[16], UNSAFE.arrayBaseOffset(Object[].class), 16, 8);
+ throw new RuntimeException("copySwapMemory failed to throw NPE");
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+
+ // Check that invalid source & dest pointers throw IAEs (only relevant on 32-bit platforms)
+ if (UNSAFE.addressSize() == 4) {
+ long invalidPtr = (long)1 << 35; // Pick a random bit in upper 32 bits
+
+ try {
+ // Check that an invalid (not 32-bit clean) source pointer throws IAE
+ UNSAFE.copySwapMemory(null, invalidPtr, null, buf, 16, 2);
+ throw new RuntimeException("copySwapMemory failed to throw IAE for srcOffset 0x" +
+ Long.toHexString(invalidPtr));
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+
+ try {
+ // Check that an invalid (not 32-bit clean) source pointer throws IAE
+ UNSAFE.copySwapMemory(null, buf, null, invalidPtr, 16, 2);
+ throw new RuntimeException("copySwapMemory failed to throw IAE for destOffset 0x" +
+ Long.toHexString(invalidPtr));
+ } catch (IllegalArgumentException e) {
+ // good
+ }
+ }
+ } finally {
+ if (bufRaw != 0) {
+ UNSAFE.freeMemory(bufRaw);
+ }
+ }
+ }
+
+ /**
+ * Run all tests
+ *
+ * @throws RuntimeException if an error is found
+ */
+ private void test() {
+ testPositive();
+ testNegative();
+ }
+
+ public static void main(String[] args) {
+ CopySwap cs = new CopySwap();
+ cs.test();
+ }
+
+ /**
+ * Helper class to represent a "pointer" - either a heap array or
+ * a pointer to a native buffer.
+ *
+ * In the case of a native pointer, the Object is null and the offset is
+ * the absolute address of the native buffer.
+ *
+ * In the case of a heap object, the Object is a primitive array, and
+ * the offset will be set to the base offset to the first element, meaning
+ * the object and the offset together form a double-register pointer.
+ */
+ static class GenericPointer {
+ private final Object o;
+ private final long offset;
+
+ private GenericPointer(Object o, long offset) {
+ this.o = o;
+ this.offset = offset;
+ }
+
+ public String toString() {
+ return "GenericPointer(o={" + o + "}, offset=0x" + Long.toHexString(offset) + ")";
+ }
+
+ public boolean equals(Object other) {
+ if (!(other instanceof GenericPointer)) {
+ return false;
+ }
+
+ GenericPointer otherp = (GenericPointer)other;
+
+ return o == otherp.o && offset == otherp.offset;
+ }
+
+ GenericPointer(Object o) {
+ this(o, UNSAFE.arrayBaseOffset(o.getClass()));
+ }
+
+ GenericPointer(long offset) {
+ this(null, offset);
+ }
+
+ public boolean isOnHeap() {
+ return o != null;
+ }
+
+ public Object getObject() {
+ return o;
+ }
+
+ public long getOffset() {
+ return offset;
+ }
+ }
+}