test/UnsafeTest/UnsafeTest.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.lang.reflect.Field;
import sun.misc.Unsafe;

public class UnsafeTest {
  static {
    System.loadLibrary("arttest");
  }

  private static void check(int actual, int expected, String msg) {
    if (actual != expected) {
      System.logE(msg + " : " + actual + " != " + expected);
      System.exit(-1);
    }
  }

  private static void check(long actual, long expected, String msg) {
    if (actual != expected) {
      System.logE(msg + " : " + actual + " != " + expected);
      System.exit(-1);
    }
  }

  private static Unsafe getUnsafe() throws Exception {
    Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
    Field f = unsafeClass.getDeclaredField("theUnsafe");
    f.setAccessible(true);
    return (Unsafe) f.get(null);
  }

  public static void main(String[] args) throws Exception {
    Unsafe unsafe = getUnsafe();
    check(unsafe.arrayBaseOffset(boolean[].class), vmArrayBaseOffset(boolean[].class),
        "Unsafe.arrayBaseOffset(boolean[])");
    check(unsafe.arrayBaseOffset(byte[].class), vmArrayBaseOffset(byte[].class),
        "Unsafe.arrayBaseOffset(byte[])");
    check(unsafe.arrayBaseOffset(char[].class), vmArrayBaseOffset(char[].class),
        "Unsafe.arrayBaseOffset(char[])");
    check(unsafe.arrayBaseOffset(double[].class), vmArrayBaseOffset(double[].class),
        "Unsafe.arrayBaseOffset(double[])");
    check(unsafe.arrayBaseOffset(float[].class), vmArrayBaseOffset(float[].class),
        "Unsafe.arrayBaseOffset(float[])");
    check(unsafe.arrayBaseOffset(int[].class), vmArrayBaseOffset(int[].class),
        "Unsafe.arrayBaseOffset(int[])");
    check(unsafe.arrayBaseOffset(long[].class), vmArrayBaseOffset(long[].class),
        "Unsafe.arrayBaseOffset(long[])");
    check(unsafe.arrayBaseOffset(Object[].class), vmArrayBaseOffset(Object[].class),
        "Unsafe.arrayBaseOffset(Object[])");

    check(unsafe.arrayIndexScale(boolean[].class), vmArrayIndexScale(boolean[].class),
        "Unsafe.arrayIndexScale(boolean[])");
    check(unsafe.arrayIndexScale(byte[].class), vmArrayIndexScale(byte[].class),
        "Unsafe.arrayIndexScale(byte[])");
    check(unsafe.arrayIndexScale(char[].class), vmArrayIndexScale(char[].class),
        "Unsafe.arrayIndexScale(char[])");
    check(unsafe.arrayIndexScale(double[].class), vmArrayIndexScale(double[].class),
        "Unsafe.arrayIndexScale(double[])");
    check(unsafe.arrayIndexScale(float[].class), vmArrayIndexScale(float[].class),
        "Unsafe.arrayIndexScale(float[])");
    check(unsafe.arrayIndexScale(int[].class), vmArrayIndexScale(int[].class),
        "Unsafe.arrayIndexScale(int[])");
    check(unsafe.arrayIndexScale(long[].class), vmArrayIndexScale(long[].class),
        "Unsafe.arrayIndexScale(long[])");
    check(unsafe.arrayIndexScale(Object[].class), vmArrayIndexScale(Object[].class),
        "Unsafe.arrayIndexScale(Object[])");

    TestClass t = new TestClass();
    int intValue = 12345678;
    Field intField = TestClass.class.getDeclaredField("intVar");
    long intOffset = unsafe.objectFieldOffset(intField);
    check(unsafe.getInt(t, intOffset), 0, "Unsafe.getInt(Object, long) - initial");
    unsafe.putInt(t, intOffset, intValue);
    check(t.intVar, intValue, "Unsafe.putInt(Object, long, int)");
    check(unsafe.getInt(t, intOffset), intValue, "Unsafe.getInt(Object, long)");
    Field longField = TestClass.class.getDeclaredField("longVar");
    long longOffset = unsafe.objectFieldOffset(longField);
    long longValue = 1234567887654321L;
    check(unsafe.getLong(t, longOffset), 0, "Unsafe.getLong(Object, long) - initial");
    unsafe.putLong(t, longOffset, longValue);
    check(t.longVar, longValue, "Unsafe.putLong(Object, long, long)");
    check(unsafe.getLong(t, longOffset), longValue, "Unsafe.getLong(Object, long)");
  }

  private static class TestClass {
    public int intVar = 0;
    public long longVar = 0;
  }

  private static native int vmArrayBaseOffset(Class clazz);
  private static native int vmArrayIndexScale(Class clazz);
}