Unsafe.java

//
// Copyright (C) 2006 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA).  All Rights Reserved.
//
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3.  The NOSA has been approved by the Open Source
// Initiative.  See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
//
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
package sun.misc;

import java.lang.reflect.Field;

/**
 * Unsafe = unwanted. See comments in the native peer. We only have it because
 * it is required by java.util.concurrent.
 *
 * Note that in the real world, this class is only callable from the system
 * library, not application code
 */

public class Unsafe {

	private static final Unsafe theUnsafe = new Unsafe();
	public static final int ARRAY_CHAR_BASE_OFFSET = theUnsafe.arrayBaseOffset(char[].class);

	public static final int INVALID_FIELD_OFFSET = -1;

	public static Unsafe getUnsafe() {
		return theUnsafe;
		// return new Unsafe();
	}

	// field offsets are completely useless between VMs, we just return
	// a numeric id for the corresponding FieldInfo here
	public native int fieldOffset(Field f);

	public native long objectFieldOffset(Field f);

	// those do the usual CAS magic
	public native boolean compareAndSwapObject(Object oThis, long offset, Object expect, Object update);

	public native boolean compareAndSwapInt(Object oThis, long offset, int expect, int update);

	public native boolean compareAndSwapLong(Object oThis, long offset, long expect, long update);

	// that looks like some atomic conditional wait
	public native void park(boolean isAbsolute, long timeout);

	public native void unpark(Object thread);

	// various accessors
	public native int getInt(Object obj, long l);

	public native int getIntVolatile(Object obj, long l);

	@Deprecated
	public int getInt(Object obj, int offset) {
		return getInt(obj, (long) offset);
	}

	public native void putInt(Object obj, long l, int i);

	public native void putIntVolatile(Object obj, long l, int i);

	@Deprecated
	public void putInt(Object obj, int offset, int i) {
		putInt(obj, (long) offset, i);
	}

	public native void putOrderedInt(Object obj, long l, int i);

	public native Object getObject(Object obj, long l);

	public native Object getObjectVolatile(Object obj, long l);

	@Deprecated
	public Object getObject(Object obj, int offset) {
		return getObject(obj, (long) offset);
	}

	public native void putObject(Object obj, long l, Object obj1);

	public native void putObjectVolatile(Object obj, long l, Object obj1);

	@Deprecated
	public void putObject(Object obj, int offset, Object obj1) {
		putObject(obj, (long) offset, obj1);
	}

	public native void putOrderedObject(Object obj, long l, Object obj1);

	public native boolean getBoolean(Object obj, long l);

	public native boolean getBooleanVolatile(Object obj, long l);

	@Deprecated
	public boolean getBoolean(Object obj, int offset) {
		return getBoolean(obj, (long) offset);
	}

	public native void putBoolean(Object obj, long l, boolean flag);

	public native void putBooleanVolatile(Object obj, long l, boolean flag);

	@Deprecated
	public void putBoolean(Object obj, int offset, boolean flag) {
		putBoolean(obj, (long) offset, flag);
	}

	public native byte getByte(Object obj, long l);

	public native byte getByteVolatile(Object obj, long l);

	@Deprecated
	public byte getByte(Object obj, int offset) {
		return getByte(obj, (long) offset);
	}

	public native void putByte(Object obj, long l, byte byte0);

	public native void putByteVolatile(Object obj, long l, byte byte0);

	@Deprecated
	public void putByte(Object obj, int offset, byte byte0) {
		putByte(obj, (long) offset, byte0);
	}

	public native short getShort(Object obj, long l);

	public native short getShortVolatile(Object obj, long l);

	@Deprecated
	public short getShort(Object obj, int offset) {
		return getShort(obj, (long) offset);
	}

	public native void putShort(Object obj, long l, short word0);

	public native void putShortVolatile(Object obj, long l, short word0);

	@Deprecated
	public void putShort(Object obj, int offset, short word0) {
		putShort(obj, (long) offset, word0);
	}

	public native char getChar(Object obj, long l);

	public native char getCharVolatile(Object obj, long l);

	@Deprecated
	public char getChar(Object obj, int offset) {
		return getChar(obj, (long) offset);
	}

	public native void putChar(Object obj, long l, char c);

	public native void putCharVolatile(Object obj, long l, char c);

	@Deprecated
	public void putChar(Object obj, int offset, char c) {
		putChar(obj, (long) offset, c);
	}

	public native long getLong(Object obj, long l);

	public native long getLongVolatile(Object obj, long l);

	@Deprecated
	public long getLong(Object obj, int offset) {
		return getLong(obj, (long) offset);
	}

	public native void putLong(Object obj, long l, long l1);

	public native void putLongVolatile(Object obj, long l, long l1);

	public native void putOrderedLong(Object obj, long l, long l1);

	@Deprecated
	public void putLong(Object obj, int offset, long l1) {
		putLong(obj, (long) offset, l1);
	}

	public native float getFloat(Object obj, long l);

	public native float getFloatVolatile(Object obj, long l);

	@Deprecated
	public float getFloat(Object obj, int offset) {
		return getFloat(obj, (long) offset);
	}

	public native void putFloat(Object obj, long l, float f);

	public native void putFloatVolatile(Object obj, long l, float f);

	@Deprecated
	public void putFloat(Object obj, int offset, float f) {
		putFloat(obj, (long) offset, f);
	}

	public native double getDouble(Object obj, long l);

	public native double getDoubleVolatile(Object obj, long l);

	@Deprecated
	public double getDouble(Object obj, int offset) {
		return getDouble(obj, (long) offset);
	}

	public native void putDouble(Object obj, long l, double d);

	public native void putDoubleVolatile(Object obj, long l, double d);

	@Deprecated
	public void putDouble(Object obj, int offset, double d) {
		putDouble(obj, (long) offset, d);
	}

	public native void ensureClassInitialized(Class<?> cls);

	public native int arrayBaseOffset(Class<?> clazz);

	public native int arrayIndexScale(Class<?> clazz);

	// --- java.nio finally breaks object boundaries - hello, evil pointer
	// arithmetic

	/**
	 * this is really a byte[] allocation (used by java.nio.Bits). Note that
	 * object has to be explicitly freed with freeMemory() (yikes!)
	 */
	public native long allocateMemory(long bytes);

	/**
	 * to be used to free allocateMemory() allocated array objects
	 */
	public native void freeMemory(long byteArrayRef);

	/**
	 * byte access of allocateMemory() objects. Note that 'address' has to point
	 * into such an object
	 */
	public native byte getByte(long address);

	public native void putByte(long address, byte val);

	public native char getChar(long address);

	public native void putChar(long address, char val);

	public native int getInt(long address);

	public native void putInt(long address, int val);

	public native long getLong(long address);

	public native void putLong(long address, long val);

	public native float getFloat(long address);

	public native void putFloat(long address, float val);

	public native double getDouble(long address);

	public native void putDouble(long address, double val);

	public native void copyMemory(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);

	public native int pageSize();

	public native void setMemory(long address, long bytes, byte value);

	public native int getAndAddInt(Object src, long address, int val);
	
	public native long getAndAddLong(Object src, long address, long val);
}