/*
 
* Copyright (c) 2000, 2013, 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.
  
Oracle designates this
 
* particular file as subject to the "Classpath" exception as provided
 
* by Oracle in the LICENSE file that accompanied this code.
 
*
 
* 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.
 
*/

package sun.misc;

import java.security.*;
import java.lang.reflect.*;

import sun.reflect.CallerSensitive;
import sun.reflect.Reflection;


/**
 
* A collection of methods for performing low-level, unsafe operations.
 
* Although the class and all methods are public, use of this class is
 
* limited because only trusted code can obtain instances of it.
 
*
 
* @author John R. Rose
 
* @see #getUnsafe
 
*/


public final class Unsafe {

    
private static native void registerNatives();
    
static {
        
registerNatives();
        
sun.reflect.Reflection.registerMethodsToFilter(Unsafe.class, "getUnsafe");
    
}

    
private Unsafe() {}

    
private static final Unsafe theUnsafe = new Unsafe();

    
/**
     
* Provides the caller with the capability of performing unsafe
     
* operations.
     
*
     
* <p> The returned <code>Unsafe</code> object should be carefully guarded
     
* by the caller, since it can be used to read and write data at arbitrary
     
* memory addresses.
  
It must never be passed to untrusted code.
     
*
     
* <p> Most methods in this class are very low-level, and correspond to a
     
* small number of hardware instructions (on typical machines).
  
Compilers
     
* are encouraged to optimize these methods accordingly.
     
*
     
* <p> Here is a suggested idiom for using unsafe operations:
     
*
     
* <blockquote><pre>
     
* class MyTrustedClass {
     
*
   
private static final Unsafe unsafe = Unsafe.getUnsafe();
     
*
   
...
     
*
   
private long myCountAddress = ...;
     
*
   
public int getCount() { return unsafe.getByte(myCountAddress); }
     
* }
     
* </pre></blockquote>
     
*
     
* (It may assist compilers to make the local variable be
     
* <code>final</code>.)
     
*
     
* @exception
  
SecurityExceptionif a security manager exists and its
     
*
             
<code>checkPropertiesAccess</code> method doesn't allow
     
*
             
access to the system properties.
     
*/

    
@CallerSensitive
    
public static Unsafe getUnsafe() {
        
Class<?> caller = Reflection.getCallerClass();
        
if (!VM.isSystemDomainLoader(caller.getClassLoader()))
            
throw new SecurityException("Unsafe");
        
return theUnsafe;
    
}

    
/// peek and poke operations
    
/// (compilers should optimize these to memory ops)

    
// These work on object fields in the Java heap.
    
// They will not work on elements of packed arrays.

    
/**
     
* Fetches a value from a given Java variable.
     
* More specifically, fetches a field or array element within the given
     
* object <code>o</code> at the given offset, or (if <code>o</code> is
     
* null) from the memory address whose numerical value is the given
     
* offset.
     
* <p>
     
* The results are undefined unless one of the following cases is true:
     
* <ul>
     
* <li>The offset was obtained from {@link #objectFieldOffset} on
     
* the
 
 
of some Java field and the object
     
* referred to by <code>o</code> is of a class compatible with that
     
* field's class.
     
*
     
* <li>The offset and object reference <code>o</code> (either null or
     
* non-null) were both obtained via {@link #staticFieldOffset}
     
* and {@link #staticFieldBase} (respectively) from the
     
* reflective {@link Field} representation of some Java field.
     
*
     
* <li>The object referred to by <code>o</code> is an array, and the offset
     
* is an integer of the form <code>B+N*S</code>, where <code>N</code> is
     
* a valid index into the array, and <code>B</code> and <code>S</code> are
     
* the values obtained by {@link #arrayBaseOffset} and {@link
     
* #arrayIndexScale} (respectively) from the array's class.
  
The value
     
* referred to is the <code>N</code><em>th</em> element of the array.
     
*
     
* </ul>
     
* <p>
     
* If one of the above cases is true, the call references a specific Java
     
* variable (field or array element).
  
However, the results are undefined
     
* if that variable is not in fact of the type returned by this method.
     
* <p>
     
* This method refers to a variable by means of two parameters, and so
     
* it provides (in effect) a <em>double-register</em> addressing mode
     
* for Java variables.
  
When the object reference is null, this method
     
* uses its offset as an absolute address.
  
This is similar in operation
     
* to methods such as {@link #getInt(long)}, which provide (in effect) a
     
* <em>single-register</em> addressing mode for non-Java variables.
     
* However, because Java variables may have a different layout in memory
     
* from non-Java variables, programmers should not assume that these
     
* two addressing modes are ever equivalent.
  
Also, programmers should
     
* remember that offsets from the double-register addressing mode cannot
     
* be portably confused with longs used in the single-register addressing
     
* mode.
     
*
     
* @param o Java heap object in which the variable resides, if any, else
     
*
        
null
     
* @param offset indication of where the variable resides in a Java heap
     
*
        
object, if any, else a memory address locating the variable
     
*
        
statically
     
* @return the value fetched from the indicated Java variable
     
* @throws RuntimeException No defined exceptions are thrown, not even
     
*
         
{@link NullPointerException}
     
*/

    
public native int getInt(Object o, long offset);

    
/**
     
* Stores a value into a given Java variable.
     
* <p>
     
* The first two parameters are interpreted exactly as with
     
* {@link #getInt(Object, long)} to refer to a specific
     
* Java variable (field or array element).
  
The given value
     
* is stored into that variable.
     
* <p>
     
* The variable must be of the same type as the method
     
* parameter <code>x</code>.
     
*
     
* @param o Java heap object in which the variable resides, if any, else
     
*
        
null
     
* @param offset indication of where the variable resides in a Java heap
     
*
        
object, if any, else a memory address locating the variable
     
*
        
statically
     
* @param x the value to store into the indicated Java variable
     
* @throws RuntimeException No defined exceptions are thrown, not even
     
*
         
{@link NullPointerException}
     
*/

    
public native void putInt(Object o, long offset, int x);

    
/**
     
* Fetches a reference value from a given Java variable.
     
* @see #getInt(Object, long)
     
*/

    
public native Object getObject(Object o, long offset);

    
/**
     
* Stores a reference value into a given Java variable.
     
* <p>
     
* Unless the reference <code>x</code> being stored is either null
     
* or matches the field type, the results are undefined.
     
* If the reference <code>o</code> is non-null, car marks or
     
* other store barriers for that object (if the VM requires them)
     
* are updated.
     
* @see #putInt(Object, int, int)
     
*/

    
public native void putObject(Object o, long offset, Object x);

    
/** @see #getInt(Object, long) */
    
public native boolean getBoolean(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putBoolean(Object o, long offset, boolean x);
    
/** @see #getInt(Object, long) */
    
public native byte
    
getByte(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putByte(Object o, long offset, byte x);
    
/** @see #getInt(Object, long) */
    
public native short
   
getShort(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putShort(Object o, long offset, short x);
    
/** @see #getInt(Object, long) */
    
public native char
    
getChar(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putChar(Object o, long offset, char x);
    
/** @see #getInt(Object, long) */
    
public native long
    
getLong(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putLong(Object o, long offset, long x);
    
/** @see #getInt(Object, long) */
    
public native float
   
getFloat(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putFloat(Object o, long offset, float x);
    
/** @see #getInt(Object, long) */
    
public native double
  
getDouble(Object o, long offset);
    
/** @see #putInt(Object, int, int) */
    
public native void
    
putDouble(Object o, long offset, double x);

    
/**
     
* This method, like all others with 32-bit offsets, was native
     
* in a previous release but is now a wrapper which simply casts
     
* the offset to a long value.
  
It provides backward compatibility
     
* with bytecodes compiled against 1.4.
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

    
@Deprecated
    
public void putInt(Object o, int offset, int x) {
        
putInt(o, (long)offset, x);
    
}

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

    
@Deprecated
    
public void putObject(Object o, int offset, Object x) {
        
putObject(o, (long)offset, x);
    
}

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

    
@Deprecated
    
public void putLong(Object o, int offset, long x) {
        
putLong(o, (long)offset, x);
    
}

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
/**
     
* @deprecated As of 1.4.1, cast the 32-bit offset argument to a long.
     
* See {@link #staticFieldOffset}.
     
*/

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

    
// These work on values in the C heap.

    
/**
     
* Fetches a value from a given memory address.
  
If the address is zero, or
     
* does not point into a block obtained from {@link #allocateMemory}, the
     
* results are undefined.
     
*
     
* @see #allocateMemory
     
*/

    
public native byte
    
getByte(long address);

    
/**
     
* Stores a value into a given memory address.
  
If the address is zero, or
     
* does not point into a block obtained from {@link #allocateMemory}, the
     
* results are undefined.
     
*
     
* @see #getByte(long)
     
*/

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

    
/** @see #getByte(long) */
    
public native short
   
getShort(long address);
    
/** @see #putByte(long, byte) */
    
public native void
    
putShort(long address, short x);
    
/** @see #getByte(long) */
    
public native char
    
getChar(long address);
    
/** @see #putByte(long, byte) */
    
public native void
    
putChar(long address, char x);
    
/** @see #getByte(long) */
    
public native int
     
getInt(long address);
    
/** @see #putByte(long, byte) */
    
public native void
    
putInt(long address, int x);
    
/** @see #getByte(long) */
    
public native long
    
getLong(long address);
    
/** @see #putByte(long, byte) */
    
public native void
    
putLong(long address, long x);
    
/** @see #getByte(long) */
    
public native float
   
getFloat(long address);
    
/** @see #putByte(long, byte) */
    
public native void
    
putFloat(long address, float x);
    
/** @see #getByte(long) */
    
public native double
  
getDouble(long address);
    
/** @see #putByte(long, byte) */
    
public native void
    
putDouble(long address, double x);

    
/**
     
* Fetches a native pointer from a given memory address.
  
If the address is
     
* zero, or does not point into a block obtained from {@link
     
* #allocateMemory}, the results are undefined.
     
*
     
* <p> If the native pointer is less than 64 bits wide, it is extended as
     
* an unsigned number to a Java long.
  
The pointer may be indexed by any
     
* given byte offset, simply by adding that offset (as a simple integer) to
     
* the long representing the pointer.
  
The number of bytes actually read
     
* from the target address maybe determined by consulting {@link
     
* #addressSize}.
     
*
     
* @see #allocateMemory
     
*/

    
public native long getAddress(long address);

    
/**
     
* Stores a native pointer into a given memory address.
  
If the address is
     
* zero, or does not point into a block obtained from {@link
     
* #allocateMemory}, the results are undefined.
     
*
     
* <p> The number of bytes actually written at the target address maybe
     
* determined by consulting {@link #addressSize}.
     
*
     
* @see #getAddress(long)
     
*/

    
public native void putAddress(long address, long x);

    
/// wrappers for malloc, realloc, free:

    
/**
     
* Allocates a new block of native memory, of the given size in bytes.
  
The
     
* contents of the memory are uninitialized; they will generally be
     
* garbage.
  
The resulting native pointer will never be zero, and will be
     
* aligned for all value types.
  
Dispose of this memory by calling {@link
     
* #freeMemory}, or resize it with {@link #reallocateMemory}.
     
*
     
* @throws IllegalArgumentException if the size is negative or too large
     
*
         
for the native size_t type
     
*
     
* @throws OutOfMemoryError if the allocation is refused by the system
     
*
     
* @see #getByte(long)
     
* @see #putByte(long, byte)
     
*/

    
public native long allocateMemory(long bytes);

    
/**
     
* Resizes a new block of native memory, to the given size in bytes.
  
The
     
* contents of the new block past the size of the old block are
     
* uninitialized; they will generally be garbage.
  
The resulting native
     
* pointer will be zero if and only if the requested size is zero.
  
The
     
* resulting native pointer will be aligned for all value types.
  
Dispose
     
* of this memory by calling {@link #freeMemory}, or resize it with {@link
     
* #reallocateMemory}.
  
The address passed to this method may be null, in
     
* which case an allocation will be performed.
     
*
     
* @throws IllegalArgumentException if the size is negative or too large
     
*
         
for the native size_t type
     
*
     
* @throws OutOfMemoryError if the allocation is refused by the system
     
*
     
* @see #allocateMemory
     
*/

    
public native long reallocateMemory(long address, long bytes);

    
/**
     
* Sets all bytes in a given block of memory to a fixed value
     
* (usually zero).
     
*
     
* <p>This method determines a block's base address by means of two parameters,
     
* and so it provides (in effect) a <em>double-register</em> addressing mode,
     
* as discussed in {@link #getInt(Object,long)}.
  
When the object reference is null,
     
* the offset supplies an absolute base address.
     
*
     
* <p>The stores are in coherent (atomic) units of a size determined
     
* by the address and length parameters.
  
If the effective address and
     
* length are all even modulo 8, the stores take place in 'long' units.
     
* If the effective address and length are (resp.) even modulo 4 or 2,
     
* the stores take place in units of 'int' or 'short'.
     
*
     
* @since 1.7
     
*/

    
public native void setMemory(Object o, long offset, long bytes, byte value);

    
/**
     
* Sets all bytes in a given block of memory to a fixed value
     
* (usually zero).
  
This provides a <em>single-register</em> addressing mode,
     
* as discussed in {@link #getInt(Object,long)}.
     
*
     
* <p>Equivalent to <code>setMemory(null, address, bytes, value)</code>.
     
*/

    
public void setMemory(long address, long bytes, byte value) {
        
setMemory(null, address, bytes, value);
    
}

    
/**
     
* Sets all bytes in a given block of memory to a copy of another
     
* block.
     
*
     
* <p>This method determines each block's base address by means of two parameters,
     
* and so it provides (in effect) a <em>double-register</em> addressing mode,
     
* as discussed in {@link #getInt(Object,long)}.
  
When the object reference is null,
     
* the offset supplies an absolute base address.
     
*
     
* <p>The transfers are in coherent (atomic) units of a size determined
     
* by the address and length parameters.
  
If the effective addresses and
     
* length are all even modulo 8, the transfer takes place in 'long' units.
     
* If the effective addresses and length are (resp.) even modulo 4 or 2,
     
* the transfer takes place in units of 'int' or 'short'.
     
*
     
* @since 1.7
     
*/

    
public native void copyMemory(Object srcBase, long srcOffset,
                                  
Object destBase, long destOffset,
                                  
long bytes);
    
/**
     
* Sets all bytes in a given block of memory to a copy of another
     
* block.
  
This provides a <em>single-register</em> addressing mode,
     
* as discussed in {@link #getInt(Object,long)}.
     
*
     
* Equivalent to <code>copyMemory(null, srcAddress, null, destAddress, bytes)</code>.
     
*/

    
public void copyMemory(long srcAddress, long destAddress, long bytes) {
        
copyMemory(null, srcAddress, null, destAddress, bytes);
    
}

    
/**
     
* Disposes of a block of native memory, as obtained from {@link
     
* #allocateMemory} or {@link #reallocateMemory}.
  
The address passed to
     
* this method may be null, in which case no action is taken.
     
*
     
* @see #allocateMemory
     
*/

    
public native void freeMemory(long address);

    
/// random queries

    
/**
     
* This constant differs from all results that will ever be returned from
     
* {@link #staticFieldOffset}, {@link #objectFieldOffset},
     
* or {@link #arrayBaseOffset}.
     
*/

    
public static final int INVALID_FIELD_OFFSET
   
= -1;

    
/**
     
* Returns the offset of a field, truncated to 32 bits.
     
* This method is implemented as follows:
     
* <blockquote><pre>
     
* public int fieldOffset(Field f) {
     
*if (Modifier.isStatic(f.getModifiers()))
     
*
         
return (int) staticFieldOffset(f);
     
*else
     
*
         
return (int) objectFieldOffset(f);
     
* }
     
* </pre></blockquote>
     
* @deprecated As of 1.4.1, use {@link #staticFieldOffset} for static
     
* fields and {@link #objectFieldOffset} for non-static fields.
     
*/

    
@Deprecated
    
public int fieldOffset(Field f) {
        
if (Modifier.isStatic(f.getModifiers()))
            
return (int) staticFieldOffset(f);
        
else
            
return
(int) objectFieldOffset(f);
    
}

    
/**
     
* Returns the base address for accessing some static field
     
* in the given class.
  
This method is implemented as follows:
     
* <blockquote><pre>
     
* public Object staticFieldBase(Class c) {
     
*Field[] fields = c.getDeclaredFields();
     
*for (int i = 0; i < fields.length; i++) {
     
*
         
if (Modifier.isStatic(fields[i].getModifiers())) {
     
*
             
return staticFieldBase(fields[i]);
     
*
         
}
     
*}
     
*return null;
     
* }
     
* </pre></blockquote>
     
* @deprecated As of 1.4.1, use {@link #staticFieldBase(Field)}
     
* to obtain the base pertaining to a specific {@link Field}.
     
* This method works only for JVMs which store all statics
     
* for a given class in one place.
     
*/

    
@Deprecated
    
public Object staticFieldBase(Class<?> c) {
        
Field[] fields = c.getDeclaredFields();
        
for (int i = 0; i < fields.length; i++) {
            
if (Modifier.isStatic(fields[i].getModifiers())) {
                
return staticFieldBase(fields[i]);
            
}
        
}
        
return null;
    
}

    
/**
     
* Report the location of a given field in the storage allocation of its
     
* class.
  
Do not expect to perform any sort of arithmetic on this offset;
     
* it is just a cookie which is passed to the unsafe heap memory accessors.
     
*
     
* <p>Any given field will always have the same offset and base, and no
     
* two distinct fields of the same class will ever have the same offset
     
* and base.
     
*
     
* <p>As of 1.4.1, offsets for fields are represented as long values,
     
* although the Sun JVM does not use the most significant 32 bits.
     
* However, JVM implementations which store static fields at absolute
     
* addresses can use long offsets and null base pointers to express
     
* the field locations in a form usable by {@link #getInt(Object,long)}.
     
* Therefore, code which will be ported to such JVMs on 64-bit platforms
     
* must preserve all bits of static field offsets.
     
* @see #getInt(Object, long)
     
*/

    
public native long staticFieldOffset(Field f);

    
/**
     
* Report the location of a given static field, in conjunction with {@link
     
* #staticFieldBase}.
     
* <p>Do not expect to perform any sort of arithmetic on this offset;
     
* it is just a cookie which is passed to the unsafe heap memory accessors.
     
*
     
* <p>Any given field will always have the same offset, and no two distinct
     
* fields of the same class will ever have the same offset.
     
*
     
* <p>As of 1.4.1, offsets for fields are represented as long values,
     
* although the Sun JVM does not use the most significant 32 bits.
     
* It is hard to imagine a JVM technology which needs more than
     
* a few bits to encode an offset within a non-array object,
     
* However, for consistency with other methods in this class,
     
* this method reports its result as a long value.
     
* @see #getInt(Object, long)
     
*/

    
public native long objectFieldOffset(Field f);

    
/**
     
* Report the location of a given static field, in conjunction with {@link
     
* #staticFieldOffset}.
     
* <p>Fetch the base "Object", if any, with which static fields of the
     
* given class can be accessed via methods like {@link #getInt(Object,
     
* long)}.
  
This value may be null.This value may refer to an object
     
* which is a "cookie", not guaranteed to be a real Object, and it should
     
* not be used in any way except as argument to the get and put routines in
     
* this class.
     
*/

    
public native Object staticFieldBase(Field f);

    
/**
     
* Detect if the given class may need to be initialized. This is often
     
* needed in conjunction with obtaining the static field base of a
     
* class.
     
* @return false only if a call to {@code ensureClassInitialized} would have no effect
     
*/

    
public native boolean shouldBeInitialized(Class<?> c);

    
/**
     
* Ensure the given class has been initialized. This is often
     
* needed in conjunction with obtaining the static field base of a
     
* class.
     
*/

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

    
/**
     
* Report the offset of the first element in the storage allocation of a
     
* given array class.
  
If {@link #arrayIndexScale} returns a non-zero value
     
* for the same class, you may use that scale factor, together with this
     
* base offset, to form new offsets to access elements of arrays of the
     
* given class.
     
*
     
* @see #getInt(Object, long)
     
* @see #putInt(Object, long, int)
     
*/

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

    
/** The value of {@code arrayBaseOffset(boolean[].class)} */
    
public static final int ARRAY_BOOLEAN_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(boolean[].class);

    
/** The value of {@code arrayBaseOffset(byte[].class)} */
    
public static final int ARRAY_BYTE_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(byte[].class);

    
/** The value of {@code arrayBaseOffset(short[].class)} */
    
public static final int ARRAY_SHORT_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(short[].class);

    
/** The value of {@code arrayBaseOffset(char[].class)} */
    
public static final int ARRAY_CHAR_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(char[].class);

    
/** The value of {@code arrayBaseOffset(int[].class)} */
    
public static final int ARRAY_INT_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(int[].class);

    
/** The value of {@code arrayBaseOffset(long[].class)} */
    
public static final int ARRAY_LONG_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(long[].class);

    
/** The value of {@code arrayBaseOffset(float[].class)} */
    
public static final int ARRAY_FLOAT_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(float[].class);

    
/** The value of {@code arrayBaseOffset(double[].class)} */
    
public static final int ARRAY_DOUBLE_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(double[].class);

    
/** The value of {@code arrayBaseOffset(Object[].class)} */
    
public static final int ARRAY_OBJECT_BASE_OFFSET
            
= theUnsafe.arrayBaseOffset(Object[].class);

    
/**
     
* Report the scale factor for addressing elements in the storage
     
* allocation of a given array class.
  
However, arrays of "narrow" types
     
* will generally not work properly with accessors like {@link
     
* #getByte(Object, int)}, so the scale factor for such classes is reported
     
* as zero.
     
*
     
* @see #arrayBaseOffset
     
* @see #getInt(Object, long)
     
* @see #putInt(Object, long, int)
     
*/

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

    
/** The value of {@code arrayIndexScale(boolean[].class)} */
    
public static final int ARRAY_BOOLEAN_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(boolean[].class);

    
/** The value of {@code arrayIndexScale(byte[].class)} */
    
public static final int ARRAY_BYTE_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(byte[].class);

    
/** The value of {@code arrayIndexScale(short[].class)} */
    
public static final int ARRAY_SHORT_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(short[].class);

    
/** The value of {@code arrayIndexScale(char[].class)} */
    
public static final int ARRAY_CHAR_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(char[].class);

    
/** The value of {@code arrayIndexScale(int[].class)} */
    
public static final int ARRAY_INT_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(int[].class);

    
/** The value of {@code arrayIndexScale(long[].class)} */
    
public static final int ARRAY_LONG_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(long[].class);

    
/** The value of {@code arrayIndexScale(float[].class)} */
    
public static final int ARRAY_FLOAT_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(float[].class);

    
/** The value of {@code arrayIndexScale(double[].class)} */
    
public static final int ARRAY_DOUBLE_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(double[].class);

    
/** The value of {@code arrayIndexScale(Object[].class)} */
    
public static final int ARRAY_OBJECT_INDEX_SCALE
            
= theUnsafe.arrayIndexScale(Object[].class);

    
/**
     
* Report the size in bytes of a native pointer, as stored via {@link
     
* #putAddress}.
  
This value will be either 4 or 8.Note that the sizes of
     
* other primitive types (as stored in native memory blocks) is determined
     
* fully by their information content.
     
*/

    
public native int addressSize();

    
/** The value of {@code addressSize()} */
    
public static final int ADDRESS_SIZE = theUnsafe.addressSize();

    
/**
     
* Report the size in bytes of a native memory page (whatever that is).
     
* This value will always be a power of two.
     
*/

    
public native int pageSize();


    
/// random trusted operations from JNI:

    
/**
     
* Tell the VM to define a class, without security checks.
  
By default, the
     
* class loader and protection domain come from the caller's class.
     
*/

    
public native Class<?> defineClass(String name, byte[] b, int off, int len,
                                       
ClassLoader loader,
                                       
ProtectionDomain protectionDomain);

    
/**
     
* Define a class but do not make it known to the class loader or system dictionary.
     
* <p>
     
* For each CP entry, the corresponding CP patch must either be null or have
     
* the a format that matches its tag:
     
* <ul>
     
* <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
     
* <li>Utf8: a string (must have suitable syntax if used as signature or name)
     
* <li>Class: any java.lang.Class object
     
* <li>String: any object (not just a java.lang.String)
     
* <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
     
* </ul>
     
* @params hostClass context for linkage, access control, protection domain, and class loader
     
* @params data
      
bytes of a class file
     
* @params cpPatches where non-null entries exist, they replace corresponding CP entries in data
     
*/

    
public native Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches);


    
/** Allocate an instance but do not run any constructor.
        
Initializes the class if it has not yet been. */

    
public native Object allocateInstance(Class<?> cls)
        
throws InstantiationException;

    
/** Lock the object.
  
It must get unlocked via {@link #monitorExit}. */
    
@Deprecated
    
public native void monitorEnter(Object o);

    
/**
     
* Unlock the object.
  
It must have been locked via {@link
     
* #monitorEnter}.
     
*/

    
@Deprecated
    
public native void monitorExit(Object o);

    
/**
     
* Tries to lock the object.
  
Returns true or false to indicate
     
* whether the lock succeeded.
  
If it did, the object must be
     
* unlocked via {@link #monitorExit}.
     
*/

    
@Deprecated
    
public native boolean tryMonitorEnter(Object o);

    
/** Throw the exception without telling the verifier. */
    
public native void throwException(Throwable ee);


    
/**
     
* Atomically update Java variable to <tt>x</tt> if it is currently
     
* holding <tt>expected</tt>.
     
* @return <tt>true</tt> if successful
     
*/

    
public final native boolean compareAndSwapObject(Object o, long offset,
                                                     
Object expected,
                                                     
Object x);

    
/**
     
* Atomically update Java variable to <tt>x</tt> if it is currently
     
* holding <tt>expected</tt>.
     
* @return <tt>true</tt> if successful
     
*/

    
public final native boolean compareAndSwapInt(Object o, long offset,
                                                  
int expected,
                                                  
int x);

    
/**
     
* Atomically update Java variable to <tt>x</tt> if it is currently
     
* holding <tt>expected</tt>.
     
* @return <tt>true</tt> if successful
     
*/

    
public final native boolean compareAndSwapLong(Object o, long offset,
                                                   
long expected,
                                                   
long x);

    
/**
     
* Fetches a reference value from a given Java variable, with volatile
     
* load semantics. Otherwise identical to {@link #getObject(Object, long)}
     
*/

    
public native Object getObjectVolatile(Object o, long offset);

    
/**
     
* Stores a reference value into a given Java variable, with
     
* volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
     
*/

    
public native void
    
putObjectVolatile(Object o, long offset, Object x);

    
/** Volatile version of {@link #getInt(Object, long)}
  
*/

    
public native int
     
getIntVolatile(Object o, long offset);

    
/** Volatile version of {@link #putInt(Object, long, int)}
  
*/

    
public native void
    
putIntVolatile(Object o, long offset, int x);

    
/** Volatile version of {@link #getBoolean(Object, long)}
  
*/

    
public native boolean getBooleanVolatile(Object o, long offset);

    
/** Volatile version of {@link #putBoolean(Object, long, boolean)}
  
*/

    
public native void
    
putBooleanVolatile(Object o, long offset, boolean x);

    
/** Volatile version of {@link #getByte(Object, long)}
  
*/

    
public native byte
    
getByteVolatile(Object o, long offset);

    
/** Volatile version of {@link #putByte(Object, long, byte)}
  
*/

    
public native void
    
putByteVolatile(Object o, long offset, byte x);

    
/** Volatile version of {@link #getShort(Object, long)}
  
*/

    
public native short
   
getShortVolatile(Object o, long offset);

    
/** Volatile version of {@link #putShort(Object, long, short)}
  
*/

    
public native void
    
putShortVolatile(Object o, long offset, short x);

    
/** Volatile version of {@link #getChar(Object, long)}
  
*/

    
public native char
    
getCharVolatile(Object o, long offset);

    
/** Volatile version of {@link #putChar(Object, long, char)}
  
*/

    
public native void
    
putCharVolatile(Object o, long offset, char x);

    
/** Volatile version of {@link #getLong(Object, long)}
  
*/

    
public native long
    
getLongVolatile(Object o, long offset);

    
/** Volatile version of {@link #putLong(Object, long, long)}
  
*/

    
public native void
    
putLongVolatile(Object o, long offset, long x);

    
/** Volatile version of {@link #getFloat(Object, long)}
  
*/

    
public native float
   
getFloatVolatile(Object o, long offset);

    
/** Volatile version of {@link #putFloat(Object, long, float)}
  
*/

    
public native void
    
putFloatVolatile(Object o, long offset, float x);

    
/** Volatile version of {@link #getDouble(Object, long)}
  
*/

    
public native double
  
getDoubleVolatile(Object o, long offset);

    
/** Volatile version of {@link #putDouble(Object, long, double)}
  
*/

    
public native void
    
putDoubleVolatile(Object o, long offset, double x);

    
/**
     
* Version of {@link #putObjectVolatile(Object, long, Object)}
     
* that does not guarantee immediate visibility of the store to
     
* other threads. This method is generally only useful if the
     
* underlying field is a Java volatile (or if an array cell, one
     
* that is otherwise only accessed using volatile accesses).
     
*/

    
public native void
    
putOrderedObject(Object o, long offset, Object x);

    
/** Ordered/Lazy version of {@link #putIntVolatile(Object, long, int)}
  
*/

    
public native void
    
putOrderedInt(Object o, long offset, int x);

    
/** Ordered/Lazy version of {@link #putLongVolatile(Object, long, long)} */
    
public native void
    
putOrderedLong(Object o, long offset, long x);

    
/**
     
* Unblock the given thread blocked on <tt>park</tt>, or, if it is
     
* not blocked, cause the subsequent call to <tt>park</tt> not to
     
* block.
  
Note: this operation is "unsafe" solely because the
     
* caller must somehow ensure that the thread has not been
     
* destroyed. Nothing special is usually required to ensure this
     
* when called from Java (in which there will ordinarily be a live
     
* reference to the thread) but this is not nearly-automatically
     
* so when calling from native code.
     
* @param thread the thread to unpark.
     
*
     
*/

    
public native void unpark(Object thread);

    
/**
     
* Block current thread, returning when a balancing
     
* <tt>unpark</tt> occurs, or a balancing <tt>unpark</tt> has
     
* already occurred, or the thread is interrupted, or, if not
     
* absolute and time is not zero, the given time nanoseconds have
     
* elapsed, or if absolute, the given deadline in milliseconds
     
* since Epoch has passed, or spuriously (i.e., returning for no
     
* "reason"). Note: This operation is in the Unsafe class only
     
* because <tt>unpark</tt> is, so it would be strange to place it
     
* elsewhere.
     
*/

    
public native void park(boolean isAbsolute, long time);

    
/**
     
* Gets the load average in the system run queue assigned
     
* to the available processors averaged over various periods of time.
     
* This method retrieves the given <tt>nelem</tt> samples and
     
* assigns to the elements of the given <tt>loadavg</tt> array.
     
* The system imposes a maximum of 3 samples, representing
     
* averages over the last 1,
  
5,and15 minutes, respectively.
     
*
     
* @params loadavg an array of double of size nelems
     
* @params nelems the number of samples to be retrieved and
     
*
         
must be 1 to 3.
     
*
     
* @return the number of samples actually retrieved; or -1
     
*
         
if the load average is unobtainable.
     
*/

    
public native int getLoadAverage(double[] loadavg, int nelems);

    
// The following contain CAS-based Java implementations used on
    
// platforms not supporting native instructions

    
/**
     
* Atomically adds the given value to the current value of a field
     
* or array element within the given object <code>o</code>
     
* at the given <code>offset</code>.
     
*
     
* @param o object/array to update the field/element in
     
* @param offset field/element offset
     
* @param delta the value to add
     
* @return the previous value
     
* @since 1.8
     
*/

    
public final int getAndAddInt(Object o, long offset, int delta) {
        
int v;
        
do {
            
v = getIntVolatile(o, offset);
        
} while (!compareAndSwapInt(o, offset, v, v + delta));
        
return v;
    
}

    
/**
     
* Atomically adds the given value to the current value of a field
     
* or array element within the given object <code>o</code>
     
* at the given <code>offset</code>.
     
*
     
* @param o object/array to update the field/element in
     
* @param offset field/element offset
     
* @param delta the value to add
     
* @return the previous value
     
* @since 1.8
     
*/

    
public final long getAndAddLong(Object o, long offset, long delta) {
        
long v;
        
do {
            
v = getLongVolatile(o, offset);
        
} while (!compareAndSwapLong(o, offset, v, v + delta));
        
return v;
    
}

    
/**
     
* Atomically exchanges the given value with the current value of
     
* a field or array element within the given object <code>o</code>
     
* at the given <code>offset</code>.
     
*
     
* @param o object/array to update the field/element in
     
* @param offset field/element offset
     
* @param newValue new value
     
* @return the previous value
     
* @since 1.8
     
*/

    
public final int getAndSetInt(Object o, long offset, int newValue) {
        
int v;
        
do {
            
v = getIntVolatile(o, offset);
        
} while (!compareAndSwapInt(o, offset, v, newValue));
        
return v;
    
}

    
/**
     
* Atomically exchanges the given value with the current value of
     
* a field or array element within the given object <code>o</code>
     
* at the given <code>offset</code>.
     
*
     
* @param o object/array to update the field/element in
     
* @param offset field/element offset
     
* @param newValue new value
     
* @return the previous value
     
* @since 1.8
     
*/

    
public final long getAndSetLong(Object o, long offset, long newValue) {
        
long v;
        
do {
            
v = getLongVolatile(o, offset);
        
} while (!compareAndSwapLong(o, offset, v, newValue));
        
return v;
    
}

    
/**
     
* Atomically exchanges the given reference value with the current
     
* reference value of a field or array element within the given
     
* object <code>o</code> at the given <code>offset</code>.
     
*
     
* @param o object/array to update the field/element in
     
* @param offset field/element offset
     
* @param newValue new value
     
* @return the previous value
     
* @since 1.8
     
*/

    
public final Object getAndSetObject(Object o, long offset, Object newValue) {
        
Object v;
        
do {
            
v = getObjectVolatile(o, offset);
        
} while (!compareAndSwapObject(o, offset, v, newValue));
        
return v;
    
}


    
/**
     
* Ensures lack of reordering of loads before the fence
     
* with loads or stores after the fence.
     
* @since 1.8
     
*/

    
public native void loadFence();

    
/**
     
* Ensures lack of reordering of stores before the fence
     
* with loads or stores after the fence.
     
* @since 1.8
     
*/

    
public native void storeFence();

    
/**
     
* Ensures lack of reordering of loads or stores before the fence
     
* with loads or stores after the fence.
     
* @since 1.8
     
*/

    
public native void fullFence();

    
/**
     
* Throws IllegalAccessError; for use by the VM.
     
* @since 1.8
     
*/
    
private static void throwIllegalAccessError() {
       
throw new IllegalAccessError();
    
}

}