1 /*
   2  * Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.internal.misc;
  27 
  28 import java.lang.reflect.Field;
  29 import java.security.ProtectionDomain;
  30 
  31 import sun.reflect.CallerSensitive;
  32 import sun.reflect.Reflection;
  33 import jdk.internal.misc.VM;
  34 
  35 import jdk.internal.HotSpotIntrinsicCandidate;
  36 
  37 
  38 /**
  39  * A collection of methods for performing low-level, unsafe operations.
  40  * Although the class and all methods are public, use of this class is
  41  * limited because only trusted code can obtain instances of it.
  42  *
  43  * @author John R. Rose
  44  * @see #getUnsafe
  45  */
  46 
  47 public final class Unsafe {
  48 
  49     private static native void registerNatives();
  50     static {
  51         registerNatives();
  52         sun.reflect.Reflection.registerMethodsToFilter(Unsafe.class, "getUnsafe");
  53     }
  54 
  55     private Unsafe() {}
  56 
  57     private static final Unsafe theUnsafe = new Unsafe();
  58 
  59     /**
  60      * Provides the caller with the capability of performing unsafe
  61      * operations.
  62      *
  63      * <p>The returned {@code Unsafe} object should be carefully guarded
  64      * by the caller, since it can be used to read and write data at arbitrary
  65      * memory addresses.  It must never be passed to untrusted code.
  66      *
  67      * <p>Most methods in this class are very low-level, and correspond to a
  68      * small number of hardware instructions (on typical machines).  Compilers
  69      * are encouraged to optimize these methods accordingly.
  70      *
  71      * <p>Here is a suggested idiom for using unsafe operations:
  72      *
  73      * <pre> {@code
  74      * class MyTrustedClass {
  75      *   private static final Unsafe unsafe = Unsafe.getUnsafe();
  76      *   ...
  77      *   private long myCountAddress = ...;
  78      *   public int getCount() { return unsafe.getByte(myCountAddress); }
  79      * }}</pre>
  80      *
  81      * (It may assist compilers to make the local variable {@code final}.)
  82      *
  83      * @throws  SecurityException  if a security manager exists and its
  84      *          {@code checkPropertiesAccess} method doesn't allow
  85      *          access to the system properties.
  86      */
  87     @CallerSensitive
  88     public static Unsafe getUnsafe() {
  89         Class<?> caller = Reflection.getCallerClass();
  90         if (!VM.isSystemDomainLoader(caller.getClassLoader()))
  91             throw new SecurityException("Unsafe");
  92         return theUnsafe;
  93     }
  94 
  95     /// peek and poke operations
  96     /// (compilers should optimize these to memory ops)
  97 
  98     // These work on object fields in the Java heap.
  99     // They will not work on elements of packed arrays.
 100 
 101     /**
 102      * Fetches a value from a given Java variable.
 103      * More specifically, fetches a field or array element within the given
 104      * object {@code o} at the given offset, or (if {@code o} is null)
 105      * from the memory address whose numerical value is the given offset.
 106      * <p>
 107      * The results are undefined unless one of the following cases is true:
 108      * <ul>
 109      * <li>The offset was obtained from {@link #objectFieldOffset} on
 110      * the {@link java.lang.reflect.Field} of some Java field and the object
 111      * referred to by {@code o} is of a class compatible with that
 112      * field's class.
 113      *
 114      * <li>The offset and object reference {@code o} (either null or
 115      * non-null) were both obtained via {@link #staticFieldOffset}
 116      * and {@link #staticFieldBase} (respectively) from the
 117      * reflective {@link Field} representation of some Java field.
 118      *
 119      * <li>The object referred to by {@code o} is an array, and the offset
 120      * is an integer of the form {@code B+N*S}, where {@code N} is
 121      * a valid index into the array, and {@code B} and {@code S} are
 122      * the values obtained by {@link #arrayBaseOffset} and {@link
 123      * #arrayIndexScale} (respectively) from the array's class.  The value
 124      * referred to is the {@code N}<em>th</em> element of the array.
 125      *
 126      * </ul>
 127      * <p>
 128      * If one of the above cases is true, the call references a specific Java
 129      * variable (field or array element).  However, the results are undefined
 130      * if that variable is not in fact of the type returned by this method.
 131      * <p>
 132      * This method refers to a variable by means of two parameters, and so
 133      * it provides (in effect) a <em>double-register</em> addressing mode
 134      * for Java variables.  When the object reference is null, this method
 135      * uses its offset as an absolute address.  This is similar in operation
 136      * to methods such as {@link #getInt(long)}, which provide (in effect) a
 137      * <em>single-register</em> addressing mode for non-Java variables.
 138      * However, because Java variables may have a different layout in memory
 139      * from non-Java variables, programmers should not assume that these
 140      * two addressing modes are ever equivalent.  Also, programmers should
 141      * remember that offsets from the double-register addressing mode cannot
 142      * be portably confused with longs used in the single-register addressing
 143      * mode.
 144      *
 145      * @param o Java heap object in which the variable resides, if any, else
 146      *        null
 147      * @param offset indication of where the variable resides in a Java heap
 148      *        object, if any, else a memory address locating the variable
 149      *        statically
 150      * @return the value fetched from the indicated Java variable
 151      * @throws RuntimeException No defined exceptions are thrown, not even
 152      *         {@link NullPointerException}
 153      */
 154     @HotSpotIntrinsicCandidate
 155     public native int getInt(Object o, long offset);
 156 
 157     /**
 158      * Stores a value into a given Java variable.
 159      * <p>
 160      * The first two parameters are interpreted exactly as with
 161      * {@link #getInt(Object, long)} to refer to a specific
 162      * Java variable (field or array element).  The given value
 163      * is stored into that variable.
 164      * <p>
 165      * The variable must be of the same type as the method
 166      * parameter {@code x}.
 167      *
 168      * @param o Java heap object in which the variable resides, if any, else
 169      *        null
 170      * @param offset indication of where the variable resides in a Java heap
 171      *        object, if any, else a memory address locating the variable
 172      *        statically
 173      * @param x the value to store into the indicated Java variable
 174      * @throws RuntimeException No defined exceptions are thrown, not even
 175      *         {@link NullPointerException}
 176      */
 177     @HotSpotIntrinsicCandidate
 178     public native void putInt(Object o, long offset, int x);
 179 
 180     /**
 181      * Fetches a reference value from a given Java variable.
 182      * @see #getInt(Object, long)
 183      */
 184     @HotSpotIntrinsicCandidate
 185     public native Object getObject(Object o, long offset);
 186 
 187     /**
 188      * Stores a reference value into a given Java variable.
 189      * <p>
 190      * Unless the reference {@code x} being stored is either null
 191      * or matches the field type, the results are undefined.
 192      * If the reference {@code o} is non-null, card marks or
 193      * other store barriers for that object (if the VM requires them)
 194      * are updated.
 195      * @see #putInt(Object, long, int)
 196      */
 197     @HotSpotIntrinsicCandidate
 198     public native void putObject(Object o, long offset, Object x);
 199 
 200     /** @see #getInt(Object, long) */
 201     @HotSpotIntrinsicCandidate
 202     public native boolean getBoolean(Object o, long offset);
 203     /** @see #putInt(Object, long, int) */
 204     @HotSpotIntrinsicCandidate
 205     public native void    putBoolean(Object o, long offset, boolean x);
 206     /** @see #getInt(Object, long) */
 207     @HotSpotIntrinsicCandidate
 208     public native byte    getByte(Object o, long offset);
 209     /** @see #putInt(Object, long, int) */
 210     @HotSpotIntrinsicCandidate
 211     public native void    putByte(Object o, long offset, byte x);
 212     /** @see #getInt(Object, long) */
 213     @HotSpotIntrinsicCandidate
 214     public native short   getShort(Object o, long offset);
 215     /** @see #putInt(Object, long, int) */
 216     @HotSpotIntrinsicCandidate
 217     public native void    putShort(Object o, long offset, short x);
 218     /** @see #getInt(Object, long) */
 219     @HotSpotIntrinsicCandidate
 220     public native char    getChar(Object o, long offset);
 221     /** @see #putInt(Object, long, int) */
 222     @HotSpotIntrinsicCandidate
 223     public native void    putChar(Object o, long offset, char x);
 224     /** @see #getInt(Object, long) */
 225     @HotSpotIntrinsicCandidate
 226     public native long    getLong(Object o, long offset);
 227     /** @see #putInt(Object, long, int) */
 228     @HotSpotIntrinsicCandidate
 229     public native void    putLong(Object o, long offset, long x);
 230     /** @see #getInt(Object, long) */
 231     @HotSpotIntrinsicCandidate
 232     public native float   getFloat(Object o, long offset);
 233     /** @see #putInt(Object, long, int) */
 234     @HotSpotIntrinsicCandidate
 235     public native void    putFloat(Object o, long offset, float x);
 236     /** @see #getInt(Object, long) */
 237     @HotSpotIntrinsicCandidate
 238     public native double  getDouble(Object o, long offset);
 239     /** @see #putInt(Object, long, int) */
 240     @HotSpotIntrinsicCandidate
 241     public native void    putDouble(Object o, long offset, double x);
 242 
 243     // These read VM internal data.
 244 
 245     /**
 246      * Fetches an uncompressed reference value from a given native variable
 247      * ignoring the VM's compressed references mode.
 248      *
 249      * @param address a memory address locating the variable
 250      * @return the value fetched from the indicated native variable
 251      */
 252     public native Object getUncompressedObject(long address);
 253 
 254     /**
 255      * Fetches the {@link java.lang.Class} Java mirror for the given native
 256      * metaspace {@code Klass} pointer.
 257      *
 258      * @param metaspaceKlass a native metaspace {@code Klass} pointer
 259      * @return the {@link java.lang.Class} Java mirror
 260      */
 261     public native Class<?> getJavaMirror(long metaspaceKlass);
 262 
 263     /**
 264      * Fetches a native metaspace {@code Klass} pointer for the given Java
 265      * object.
 266      *
 267      * @param o Java heap object for which to fetch the class pointer
 268      * @return a native metaspace {@code Klass} pointer
 269      */
 270     public native long getKlassPointer(Object o);
 271 
 272     // These work on values in the C heap.
 273 
 274     /**
 275      * Fetches a value from a given memory address.  If the address is zero, or
 276      * does not point into a block obtained from {@link #allocateMemory}, the
 277      * results are undefined.
 278      *
 279      * @see #allocateMemory
 280      */
 281     @HotSpotIntrinsicCandidate
 282     public native byte    getByte(long address);
 283 
 284     /**
 285      * Stores a value into a given memory address.  If the address is zero, or
 286      * does not point into a block obtained from {@link #allocateMemory}, the
 287      * results are undefined.
 288      *
 289      * @see #getByte(long)
 290      */
 291     @HotSpotIntrinsicCandidate
 292     public native void    putByte(long address, byte x);
 293 
 294     /** @see #getByte(long) */
 295     @HotSpotIntrinsicCandidate
 296     public native short   getShort(long address);
 297     /** @see #putByte(long, byte) */
 298     @HotSpotIntrinsicCandidate
 299     public native void    putShort(long address, short x);
 300     /** @see #getByte(long) */
 301     @HotSpotIntrinsicCandidate
 302     public native char    getChar(long address);
 303     /** @see #putByte(long, byte) */
 304     @HotSpotIntrinsicCandidate
 305     public native void    putChar(long address, char x);
 306     /** @see #getByte(long) */
 307     @HotSpotIntrinsicCandidate
 308     public native int     getInt(long address);
 309     /** @see #putByte(long, byte) */
 310     @HotSpotIntrinsicCandidate
 311     public native void    putInt(long address, int x);
 312     /** @see #getByte(long) */
 313     @HotSpotIntrinsicCandidate
 314     public native long    getLong(long address);
 315     /** @see #putByte(long, byte) */
 316     @HotSpotIntrinsicCandidate
 317     public native void    putLong(long address, long x);
 318     /** @see #getByte(long) */
 319     @HotSpotIntrinsicCandidate
 320     public native float   getFloat(long address);
 321     /** @see #putByte(long, byte) */
 322     @HotSpotIntrinsicCandidate
 323     public native void    putFloat(long address, float x);
 324     /** @see #getByte(long) */
 325     @HotSpotIntrinsicCandidate
 326     public native double  getDouble(long address);
 327     /** @see #putByte(long, byte) */
 328     @HotSpotIntrinsicCandidate
 329     public native void    putDouble(long address, double x);
 330 
 331     /**
 332      * Fetches a native pointer from a given memory address.  If the address is
 333      * zero, or does not point into a block obtained from {@link
 334      * #allocateMemory}, the results are undefined.
 335      *
 336      * <p>If the native pointer is less than 64 bits wide, it is extended as
 337      * an unsigned number to a Java long.  The pointer may be indexed by any
 338      * given byte offset, simply by adding that offset (as a simple integer) to
 339      * the long representing the pointer.  The number of bytes actually read
 340      * from the target address may be determined by consulting {@link
 341      * #addressSize}.
 342      *
 343      * @see #allocateMemory
 344      */
 345     @HotSpotIntrinsicCandidate
 346     public native long getAddress(long address);
 347 
 348     /**
 349      * Stores a native pointer into a given memory address.  If the address is
 350      * zero, or does not point into a block obtained from {@link
 351      * #allocateMemory}, the results are undefined.
 352      *
 353      * <p>The number of bytes actually written at the target address may be
 354      * determined by consulting {@link #addressSize}.
 355      *
 356      * @see #getAddress(long)
 357      */
 358     @HotSpotIntrinsicCandidate
 359     public native void putAddress(long address, long x);
 360 
 361     /// wrappers for malloc, realloc, free:
 362 
 363     /**
 364      * Allocates a new block of native memory, of the given size in bytes.  The
 365      * contents of the memory are uninitialized; they will generally be
 366      * garbage.  The resulting native pointer will never be zero, and will be
 367      * aligned for all value types.  Dispose of this memory by calling {@link
 368      * #freeMemory}, or resize it with {@link #reallocateMemory}.
 369      *
 370      * @throws IllegalArgumentException if the size is negative or too large
 371      *         for the native size_t type
 372      *
 373      * @throws OutOfMemoryError if the allocation is refused by the system
 374      *
 375      * @see #getByte(long)
 376      * @see #putByte(long, byte)
 377      */
 378     public native long allocateMemory(long bytes);
 379 
 380     /**
 381      * Resizes a new block of native memory, to the given size in bytes.  The
 382      * contents of the new block past the size of the old block are
 383      * uninitialized; they will generally be garbage.  The resulting native
 384      * pointer will be zero if and only if the requested size is zero.  The
 385      * resulting native pointer will be aligned for all value types.  Dispose
 386      * of this memory by calling {@link #freeMemory}, or resize it with {@link
 387      * #reallocateMemory}.  The address passed to this method may be null, in
 388      * which case an allocation will be performed.
 389      *
 390      * @throws IllegalArgumentException if the size is negative or too large
 391      *         for the native size_t type
 392      *
 393      * @throws OutOfMemoryError if the allocation is refused by the system
 394      *
 395      * @see #allocateMemory
 396      */
 397     public native long reallocateMemory(long address, long bytes);
 398 
 399     /**
 400      * Sets all bytes in a given block of memory to a fixed value
 401      * (usually zero).
 402      *
 403      * <p>This method determines a block's base address by means of two parameters,
 404      * and so it provides (in effect) a <em>double-register</em> addressing mode,
 405      * as discussed in {@link #getInt(Object,long)}.  When the object reference is null,
 406      * the offset supplies an absolute base address.
 407      *
 408      * <p>The stores are in coherent (atomic) units of a size determined
 409      * by the address and length parameters.  If the effective address and
 410      * length are all even modulo 8, the stores take place in 'long' units.
 411      * If the effective address and length are (resp.) even modulo 4 or 2,
 412      * the stores take place in units of 'int' or 'short'.
 413      *
 414      * @since 1.7
 415      */
 416     public native void setMemory(Object o, long offset, long bytes, byte value);
 417 
 418     /**
 419      * Sets all bytes in a given block of memory to a fixed value
 420      * (usually zero).  This provides a <em>single-register</em> addressing mode,
 421      * as discussed in {@link #getInt(Object,long)}.
 422      *
 423      * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
 424      */
 425     public void setMemory(long address, long bytes, byte value) {
 426         setMemory(null, address, bytes, value);
 427     }
 428 
 429     /**
 430      * Sets all bytes in a given block of memory to a copy of another
 431      * block.
 432      *
 433      * <p>This method determines each block's base address by means of two parameters,
 434      * and so it provides (in effect) a <em>double-register</em> addressing mode,
 435      * as discussed in {@link #getInt(Object,long)}.  When the object reference is null,
 436      * the offset supplies an absolute base address.
 437      *
 438      * <p>The transfers are in coherent (atomic) units of a size determined
 439      * by the address and length parameters.  If the effective addresses and
 440      * length are all even modulo 8, the transfer takes place in 'long' units.
 441      * If the effective addresses and length are (resp.) even modulo 4 or 2,
 442      * the transfer takes place in units of 'int' or 'short'.
 443      *
 444      * @since 1.7
 445      */
 446     @HotSpotIntrinsicCandidate
 447     public native void copyMemory(Object srcBase, long srcOffset,
 448                                   Object destBase, long destOffset,
 449                                   long bytes);
 450     /**
 451      * Sets all bytes in a given block of memory to a copy of another
 452      * block.  This provides a <em>single-register</em> addressing mode,
 453      * as discussed in {@link #getInt(Object,long)}.
 454      *
 455      * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
 456      */
 457     public void copyMemory(long srcAddress, long destAddress, long bytes) {
 458         copyMemory(null, srcAddress, null, destAddress, bytes);
 459     }
 460 
 461     private boolean isPrimitiveArray(Class<?> c) {
 462         Class<?> componentType = c.getComponentType();
 463         return componentType != null && componentType.isPrimitive();
 464     }
 465 
 466     private native void copySwapMemory0(Object srcBase, long srcOffset,
 467                                         Object destBase, long destOffset,
 468                                         long bytes, long elemSize);
 469 
 470     /**
 471      * Copies all elements from one block of memory to another block,
 472      * *unconditionally* byte swapping the elements on the fly.
 473      *
 474      * <p>This method determines each block's base address by means of two parameters,
 475      * and so it provides (in effect) a <em>double-register</em> addressing mode,
 476      * as discussed in {@link #getInt(Object,long)}.  When the object reference is null,
 477      * the offset supplies an absolute base address.
 478      *
 479      * @since 9
 480      */
 481     public void copySwapMemory(Object srcBase, long srcOffset,
 482                                Object destBase, long destOffset,
 483                                long bytes, long elemSize) {
 484         if (bytes < 0) {
 485             throw new IllegalArgumentException();
 486         }
 487         if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
 488             throw new IllegalArgumentException();
 489         }
 490         if (bytes % elemSize != 0) {
 491             throw new IllegalArgumentException();
 492         }
 493         if ((srcBase == null && srcOffset == 0) ||
 494             (destBase == null && destOffset == 0)) {
 495             throw new NullPointerException();
 496         }
 497 
 498         // Must be off-heap, or primitive heap arrays
 499         if (srcBase != null && (srcOffset < 0 || !isPrimitiveArray(srcBase.getClass()))) {
 500             throw new IllegalArgumentException();
 501         }
 502         if (destBase != null && (destOffset < 0 || !isPrimitiveArray(destBase.getClass()))) {
 503             throw new IllegalArgumentException();
 504         }
 505 
 506         // Sanity check size and offsets on 32-bit platforms. Most
 507         // significant 32 bits must be zero.
 508         if (ADDRESS_SIZE == 4 &&
 509             (bytes >>> 32 != 0 || srcOffset >>> 32 != 0 || destOffset >>> 32 != 0)) {
 510             throw new IllegalArgumentException();
 511         }
 512 
 513         if (bytes == 0) {
 514             return;
 515         }
 516 
 517         copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
 518     }
 519 
 520    /**
 521      * Copies all elements from one block of memory to another block, byte swapping the
 522      * elements on the fly.
 523      *
 524      * This provides a <em>single-register</em> addressing mode, as
 525      * discussed in {@link #getInt(Object,long)}.
 526      *
 527      * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
 528      */
 529     public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
 530         copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
 531     }
 532 
 533     /**
 534      * Disposes of a block of native memory, as obtained from {@link
 535      * #allocateMemory} or {@link #reallocateMemory}.  The address passed to
 536      * this method may be null, in which case no action is taken.
 537      *
 538      * @see #allocateMemory
 539      */
 540     public native void freeMemory(long address);
 541 
 542     /// random queries
 543 
 544     /**
 545      * This constant differs from all results that will ever be returned from
 546      * {@link #staticFieldOffset}, {@link #objectFieldOffset},
 547      * or {@link #arrayBaseOffset}.
 548      */
 549     public static final int INVALID_FIELD_OFFSET   = -1;
 550 
 551     /**
 552      * Reports the location of a given field in the storage allocation of its
 553      * class.  Do not expect to perform any sort of arithmetic on this offset;
 554      * it is just a cookie which is passed to the unsafe heap memory accessors.
 555      *
 556      * <p>Any given field will always have the same offset and base, and no
 557      * two distinct fields of the same class will ever have the same offset
 558      * and base.
 559      *
 560      * <p>As of 1.4.1, offsets for fields are represented as long values,
 561      * although the Sun JVM does not use the most significant 32 bits.
 562      * However, JVM implementations which store static fields at absolute
 563      * addresses can use long offsets and null base pointers to express
 564      * the field locations in a form usable by {@link #getInt(Object,long)}.
 565      * Therefore, code which will be ported to such JVMs on 64-bit platforms
 566      * must preserve all bits of static field offsets.
 567      * @see #getInt(Object, long)
 568      */
 569     public native long objectFieldOffset(Field f);
 570 
 571     /**
 572      * Reports the location of a given static field, in conjunction with {@link
 573      * #staticFieldBase}.
 574      * <p>Do not expect to perform any sort of arithmetic on this offset;
 575      * it is just a cookie which is passed to the unsafe heap memory accessors.
 576      *
 577      * <p>Any given field will always have the same offset, and no two distinct
 578      * fields of the same class will ever have the same offset.
 579      *
 580      * <p>As of 1.4.1, offsets for fields are represented as long values,
 581      * although the Sun JVM does not use the most significant 32 bits.
 582      * It is hard to imagine a JVM technology which needs more than
 583      * a few bits to encode an offset within a non-array object,
 584      * However, for consistency with other methods in this class,
 585      * this method reports its result as a long value.
 586      * @see #getInt(Object, long)
 587      */
 588     public native long staticFieldOffset(Field f);
 589 
 590     /**
 591      * Reports the location of a given static field, in conjunction with {@link
 592      * #staticFieldOffset}.
 593      * <p>Fetch the base "Object", if any, with which static fields of the
 594      * given class can be accessed via methods like {@link #getInt(Object,
 595      * long)}.  This value may be null.  This value may refer to an object
 596      * which is a "cookie", not guaranteed to be a real Object, and it should
 597      * not be used in any way except as argument to the get and put routines in
 598      * this class.
 599      */
 600     public native Object staticFieldBase(Field f);
 601 
 602     /**
 603      * Detects if the given class may need to be initialized. This is often
 604      * needed in conjunction with obtaining the static field base of a
 605      * class.
 606      * @return false only if a call to {@code ensureClassInitialized} would have no effect
 607      */
 608     public native boolean shouldBeInitialized(Class<?> c);
 609 
 610     /**
 611      * Ensures the given class has been initialized. This is often
 612      * needed in conjunction with obtaining the static field base of a
 613      * class.
 614      */
 615     public native void ensureClassInitialized(Class<?> c);
 616 
 617     /**
 618      * Reports the offset of the first element in the storage allocation of a
 619      * given array class.  If {@link #arrayIndexScale} returns a non-zero value
 620      * for the same class, you may use that scale factor, together with this
 621      * base offset, to form new offsets to access elements of arrays of the
 622      * given class.
 623      *
 624      * @see #getInt(Object, long)
 625      * @see #putInt(Object, long, int)
 626      */
 627     public native int arrayBaseOffset(Class<?> arrayClass);
 628 
 629     /** The value of {@code arrayBaseOffset(boolean[].class)} */
 630     public static final int ARRAY_BOOLEAN_BASE_OFFSET
 631             = theUnsafe.arrayBaseOffset(boolean[].class);
 632 
 633     /** The value of {@code arrayBaseOffset(byte[].class)} */
 634     public static final int ARRAY_BYTE_BASE_OFFSET
 635             = theUnsafe.arrayBaseOffset(byte[].class);
 636 
 637     /** The value of {@code arrayBaseOffset(short[].class)} */
 638     public static final int ARRAY_SHORT_BASE_OFFSET
 639             = theUnsafe.arrayBaseOffset(short[].class);
 640 
 641     /** The value of {@code arrayBaseOffset(char[].class)} */
 642     public static final int ARRAY_CHAR_BASE_OFFSET
 643             = theUnsafe.arrayBaseOffset(char[].class);
 644 
 645     /** The value of {@code arrayBaseOffset(int[].class)} */
 646     public static final int ARRAY_INT_BASE_OFFSET
 647             = theUnsafe.arrayBaseOffset(int[].class);
 648 
 649     /** The value of {@code arrayBaseOffset(long[].class)} */
 650     public static final int ARRAY_LONG_BASE_OFFSET
 651             = theUnsafe.arrayBaseOffset(long[].class);
 652 
 653     /** The value of {@code arrayBaseOffset(float[].class)} */
 654     public static final int ARRAY_FLOAT_BASE_OFFSET
 655             = theUnsafe.arrayBaseOffset(float[].class);
 656 
 657     /** The value of {@code arrayBaseOffset(double[].class)} */
 658     public static final int ARRAY_DOUBLE_BASE_OFFSET
 659             = theUnsafe.arrayBaseOffset(double[].class);
 660 
 661     /** The value of {@code arrayBaseOffset(Object[].class)} */
 662     public static final int ARRAY_OBJECT_BASE_OFFSET
 663             = theUnsafe.arrayBaseOffset(Object[].class);
 664 
 665     /**
 666      * Reports the scale factor for addressing elements in the storage
 667      * allocation of a given array class.  However, arrays of "narrow" types
 668      * will generally not work properly with accessors like {@link
 669      * #getByte(Object, long)}, so the scale factor for such classes is reported
 670      * as zero.
 671      *
 672      * @see #arrayBaseOffset
 673      * @see #getInt(Object, long)
 674      * @see #putInt(Object, long, int)
 675      */
 676     public native int arrayIndexScale(Class<?> arrayClass);
 677 
 678     /** The value of {@code arrayIndexScale(boolean[].class)} */
 679     public static final int ARRAY_BOOLEAN_INDEX_SCALE
 680             = theUnsafe.arrayIndexScale(boolean[].class);
 681 
 682     /** The value of {@code arrayIndexScale(byte[].class)} */
 683     public static final int ARRAY_BYTE_INDEX_SCALE
 684             = theUnsafe.arrayIndexScale(byte[].class);
 685 
 686     /** The value of {@code arrayIndexScale(short[].class)} */
 687     public static final int ARRAY_SHORT_INDEX_SCALE
 688             = theUnsafe.arrayIndexScale(short[].class);
 689 
 690     /** The value of {@code arrayIndexScale(char[].class)} */
 691     public static final int ARRAY_CHAR_INDEX_SCALE
 692             = theUnsafe.arrayIndexScale(char[].class);
 693 
 694     /** The value of {@code arrayIndexScale(int[].class)} */
 695     public static final int ARRAY_INT_INDEX_SCALE
 696             = theUnsafe.arrayIndexScale(int[].class);
 697 
 698     /** The value of {@code arrayIndexScale(long[].class)} */
 699     public static final int ARRAY_LONG_INDEX_SCALE
 700             = theUnsafe.arrayIndexScale(long[].class);
 701 
 702     /** The value of {@code arrayIndexScale(float[].class)} */
 703     public static final int ARRAY_FLOAT_INDEX_SCALE
 704             = theUnsafe.arrayIndexScale(float[].class);
 705 
 706     /** The value of {@code arrayIndexScale(double[].class)} */
 707     public static final int ARRAY_DOUBLE_INDEX_SCALE
 708             = theUnsafe.arrayIndexScale(double[].class);
 709 
 710     /** The value of {@code arrayIndexScale(Object[].class)} */
 711     public static final int ARRAY_OBJECT_INDEX_SCALE
 712             = theUnsafe.arrayIndexScale(Object[].class);
 713 
 714     /**
 715      * Reports the size in bytes of a native pointer, as stored via {@link
 716      * #putAddress}.  This value will be either 4 or 8.  Note that the sizes of
 717      * other primitive types (as stored in native memory blocks) is determined
 718      * fully by their information content.
 719      */
 720     public native int addressSize();
 721 
 722     /** The value of {@code addressSize()} */
 723     public static final int ADDRESS_SIZE = theUnsafe.addressSize();
 724 
 725     /**
 726      * Reports the size in bytes of a native memory page (whatever that is).
 727      * This value will always be a power of two.
 728      */
 729     public native int pageSize();
 730 
 731 
 732     /// random trusted operations from JNI:
 733 
 734     /**
 735      * Tells the VM to define a class, without security checks.  By default, the
 736      * class loader and protection domain come from the caller's class.
 737      */
 738     public native Class<?> defineClass(String name, byte[] b, int off, int len,
 739                                        ClassLoader loader,
 740                                        ProtectionDomain protectionDomain);
 741 
 742     /**
 743      * Defines a class but does not make it known to the class loader or system dictionary.
 744      * <p>
 745      * For each CP entry, the corresponding CP patch must either be null or have
 746      * the a format that matches its tag:
 747      * <ul>
 748      * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
 749      * <li>Utf8: a string (must have suitable syntax if used as signature or name)
 750      * <li>Class: any java.lang.Class object
 751      * <li>String: any object (not just a java.lang.String)
 752      * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
 753      * </ul>
 754      * @param hostClass context for linkage, access control, protection domain, and class loader
 755      * @param data      bytes of a class file
 756      * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
 757      */
 758     public native Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches);
 759 
 760     /**
 761      * Allocates an instance but does not run any constructor.
 762      * Initializes the class if it has not yet been.
 763      */
 764     @HotSpotIntrinsicCandidate
 765     public native Object allocateInstance(Class<?> cls)
 766         throws InstantiationException;
 767 





















































 768     /** Throws the exception without telling the verifier. */
 769     public native void throwException(Throwable ee);
 770 
 771     /**
 772      * Atomically updates Java variable to {@code x} if it is currently
 773      * holding {@code expected}.
 774      *
 775      * <p>This operation has memory semantics of a {@code volatile} read
 776      * and write.  Corresponds to C11 atomic_compare_exchange_strong.
 777      *
 778      * @return {@code true} if successful
 779      */
 780     @HotSpotIntrinsicCandidate
 781     public final native boolean compareAndSwapObject(Object o, long offset,
 782                                                      Object expected,
 783                                                      Object x);
 784 
 785     @HotSpotIntrinsicCandidate
 786     public final native Object compareAndExchangeObjectVolatile(Object o, long offset,
 787                                                                 Object expected,
 788                                                                 Object x);
 789 
 790     @HotSpotIntrinsicCandidate
 791     public final Object compareAndExchangeObjectAcquire(Object o, long offset,
 792                                                                Object expected,
 793                                                                Object x) {
 794         return compareAndExchangeObjectVolatile(o, offset, expected, x);
 795     }
 796 
 797     @HotSpotIntrinsicCandidate
 798     public final Object compareAndExchangeObjectRelease(Object o, long offset,
 799                                                                Object expected,
 800                                                                Object x) {
 801         return compareAndExchangeObjectVolatile(o, offset, expected, x);
 802     }
 803 
 804     @HotSpotIntrinsicCandidate
 805     public final boolean weakCompareAndSwapObject(Object o, long offset,
 806                                                          Object expected,
 807                                                          Object x) {
 808         return compareAndSwapObject(o, offset, expected, x);
 809     }
 810 
 811     @HotSpotIntrinsicCandidate
 812     public final boolean weakCompareAndSwapObjectAcquire(Object o, long offset,
 813                                                                 Object expected,
 814                                                                 Object x) {
 815         return compareAndSwapObject(o, offset, expected, x);
 816     }
 817 
 818     @HotSpotIntrinsicCandidate
 819     public final boolean weakCompareAndSwapObjectRelease(Object o, long offset,
 820                                                                 Object expected,
 821                                                                 Object x) {
 822         return compareAndSwapObject(o, offset, expected, x);
 823     }
 824 
 825     /**
 826      * Atomically updates Java variable to {@code x} if it is currently
 827      * holding {@code expected}.
 828      *
 829      * <p>This operation has memory semantics of a {@code volatile} read
 830      * and write.  Corresponds to C11 atomic_compare_exchange_strong.
 831      *
 832      * @return {@code true} if successful
 833      */
 834     @HotSpotIntrinsicCandidate
 835     public final native boolean compareAndSwapInt(Object o, long offset,
 836                                                   int expected,
 837                                                   int x);
 838 
 839     @HotSpotIntrinsicCandidate
 840     public final native int compareAndExchangeIntVolatile(Object o, long offset,
 841                                                           int expected,
 842                                                           int x);
 843 
 844     @HotSpotIntrinsicCandidate
 845     public final int compareAndExchangeIntAcquire(Object o, long offset,
 846                                                          int expected,
 847                                                          int x) {
 848         return compareAndExchangeIntVolatile(o, offset, expected, x);
 849     }
 850 
 851     @HotSpotIntrinsicCandidate
 852     public final int compareAndExchangeIntRelease(Object o, long offset,
 853                                                          int expected,
 854                                                          int x) {
 855         return compareAndExchangeIntVolatile(o, offset, expected, x);
 856     }
 857 
 858     @HotSpotIntrinsicCandidate
 859     public final boolean weakCompareAndSwapInt(Object o, long offset,
 860                                                       int expected,
 861                                                       int x) {
 862         return compareAndSwapInt(o, offset, expected, x);
 863     }
 864 
 865     @HotSpotIntrinsicCandidate
 866     public final boolean weakCompareAndSwapIntAcquire(Object o, long offset,
 867                                                              int expected,
 868                                                              int x) {
 869         return compareAndSwapInt(o, offset, expected, x);
 870     }
 871 
 872     @HotSpotIntrinsicCandidate
 873     public final boolean weakCompareAndSwapIntRelease(Object o, long offset,
 874                                                              int expected,
 875                                                              int x) {
 876         return compareAndSwapInt(o, offset, expected, x);
 877     }
 878 
 879     /**
 880      * Atomically updates Java variable to {@code x} if it is currently
 881      * holding {@code expected}.
 882      *
 883      * <p>This operation has memory semantics of a {@code volatile} read
 884      * and write.  Corresponds to C11 atomic_compare_exchange_strong.
 885      *
 886      * @return {@code true} if successful
 887      */
 888     @HotSpotIntrinsicCandidate
 889     public final native boolean compareAndSwapLong(Object o, long offset,
 890                                                    long expected,
 891                                                    long x);
 892 
 893     @HotSpotIntrinsicCandidate
 894     public final native long compareAndExchangeLongVolatile(Object o, long offset,
 895                                                             long expected,
 896                                                             long x);
 897 
 898     @HotSpotIntrinsicCandidate
 899     public final long compareAndExchangeLongAcquire(Object o, long offset,
 900                                                            long expected,
 901                                                            long x) {
 902         return compareAndExchangeLongVolatile(o, offset, expected, x);
 903     }
 904 
 905     @HotSpotIntrinsicCandidate
 906     public final long compareAndExchangeLongRelease(Object o, long offset,
 907                                                            long expected,
 908                                                            long x) {
 909         return compareAndExchangeLongVolatile(o, offset, expected, x);
 910     }
 911 
 912     @HotSpotIntrinsicCandidate
 913     public final boolean weakCompareAndSwapLong(Object o, long offset,
 914                                                        long expected,
 915                                                        long x) {
 916         return compareAndSwapLong(o, offset, expected, x);
 917     }
 918 
 919     @HotSpotIntrinsicCandidate
 920     public final boolean weakCompareAndSwapLongAcquire(Object o, long offset,
 921                                                               long expected,
 922                                                               long x) {
 923         return compareAndSwapLong(o, offset, expected, x);
 924     }
 925 
 926     @HotSpotIntrinsicCandidate
 927     public final boolean weakCompareAndSwapLongRelease(Object o, long offset,
 928                                                               long expected,
 929                                                               long x) {
 930         return compareAndSwapLong(o, offset, expected, x);
 931     }
 932 
 933     /**
 934      * Fetches a reference value from a given Java variable, with volatile
 935      * load semantics. Otherwise identical to {@link #getObject(Object, long)}
 936      */
 937     @HotSpotIntrinsicCandidate
 938     public native Object getObjectVolatile(Object o, long offset);
 939 
 940     /**
 941      * Stores a reference value into a given Java variable, with
 942      * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
 943      */
 944     @HotSpotIntrinsicCandidate
 945     public native void    putObjectVolatile(Object o, long offset, Object x);
 946 
 947     /** Volatile version of {@link #getInt(Object, long)}  */
 948     @HotSpotIntrinsicCandidate
 949     public native int     getIntVolatile(Object o, long offset);
 950 
 951     /** Volatile version of {@link #putInt(Object, long, int)}  */
 952     @HotSpotIntrinsicCandidate
 953     public native void    putIntVolatile(Object o, long offset, int x);
 954 
 955     /** Volatile version of {@link #getBoolean(Object, long)}  */
 956     @HotSpotIntrinsicCandidate
 957     public native boolean getBooleanVolatile(Object o, long offset);
 958 
 959     /** Volatile version of {@link #putBoolean(Object, long, boolean)}  */
 960     @HotSpotIntrinsicCandidate
 961     public native void    putBooleanVolatile(Object o, long offset, boolean x);
 962 
 963     /** Volatile version of {@link #getByte(Object, long)}  */
 964     @HotSpotIntrinsicCandidate
 965     public native byte    getByteVolatile(Object o, long offset);
 966 
 967     /** Volatile version of {@link #putByte(Object, long, byte)}  */
 968     @HotSpotIntrinsicCandidate
 969     public native void    putByteVolatile(Object o, long offset, byte x);
 970 
 971     /** Volatile version of {@link #getShort(Object, long)}  */
 972     @HotSpotIntrinsicCandidate
 973     public native short   getShortVolatile(Object o, long offset);
 974 
 975     /** Volatile version of {@link #putShort(Object, long, short)}  */
 976     @HotSpotIntrinsicCandidate
 977     public native void    putShortVolatile(Object o, long offset, short x);
 978 
 979     /** Volatile version of {@link #getChar(Object, long)}  */
 980     @HotSpotIntrinsicCandidate
 981     public native char    getCharVolatile(Object o, long offset);
 982 
 983     /** Volatile version of {@link #putChar(Object, long, char)}  */
 984     @HotSpotIntrinsicCandidate
 985     public native void    putCharVolatile(Object o, long offset, char x);
 986 
 987     /** Volatile version of {@link #getLong(Object, long)}  */
 988     @HotSpotIntrinsicCandidate
 989     public native long    getLongVolatile(Object o, long offset);
 990 
 991     /** Volatile version of {@link #putLong(Object, long, long)}  */
 992     @HotSpotIntrinsicCandidate
 993     public native void    putLongVolatile(Object o, long offset, long x);
 994 
 995     /** Volatile version of {@link #getFloat(Object, long)}  */
 996     @HotSpotIntrinsicCandidate
 997     public native float   getFloatVolatile(Object o, long offset);
 998 
 999     /** Volatile version of {@link #putFloat(Object, long, float)}  */
1000     @HotSpotIntrinsicCandidate
1001     public native void    putFloatVolatile(Object o, long offset, float x);
1002 
1003     /** Volatile version of {@link #getDouble(Object, long)}  */
1004     @HotSpotIntrinsicCandidate
1005     public native double  getDoubleVolatile(Object o, long offset);
1006 
1007     /** Volatile version of {@link #putDouble(Object, long, double)}  */
1008     @HotSpotIntrinsicCandidate
1009     public native void    putDoubleVolatile(Object o, long offset, double x);
1010 
1011     /**
1012      * Version of {@link #putObjectVolatile(Object, long, Object)}
1013      * that does not guarantee immediate visibility of the store to
1014      * other threads. This method is generally only useful if the
1015      * underlying field is a Java volatile (or if an array cell, one
1016      * that is otherwise only accessed using volatile accesses).
1017      *
1018      * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
1019      */
1020     @HotSpotIntrinsicCandidate
1021     public native void    putOrderedObject(Object o, long offset, Object x);
1022 
1023     /** Ordered/Lazy version of {@link #putIntVolatile(Object, long, int)}  */
1024     @HotSpotIntrinsicCandidate
1025     public native void    putOrderedInt(Object o, long offset, int x);
1026 
1027     /** Ordered/Lazy version of {@link #putLongVolatile(Object, long, long)} */
1028     @HotSpotIntrinsicCandidate
1029     public native void    putOrderedLong(Object o, long offset, long x);
1030 
1031     /** Acquire version of {@link #getObjectVolatile(Object, long)} */
1032     @HotSpotIntrinsicCandidate
1033     public final Object getObjectAcquire(Object o, long offset) {
1034         return getObjectVolatile(o, offset);
1035     }
1036 
1037     /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
1038     @HotSpotIntrinsicCandidate
1039     public final boolean getBooleanAcquire(Object o, long offset) {
1040         return getBooleanVolatile(o, offset);
1041     }
1042 
1043     /** Acquire version of {@link #getByteVolatile(Object, long)} */
1044     @HotSpotIntrinsicCandidate
1045     public final byte getByteAcquire(Object o, long offset) {
1046         return getByteVolatile(o, offset);
1047     }
1048 
1049     /** Acquire version of {@link #getShortVolatile(Object, long)} */
1050     @HotSpotIntrinsicCandidate
1051     public final short getShortAcquire(Object o, long offset) {
1052         return getShortVolatile(o, offset);
1053     }
1054 
1055     /** Acquire version of {@link #getCharVolatile(Object, long)} */
1056     @HotSpotIntrinsicCandidate
1057     public final char getCharAcquire(Object o, long offset) {
1058         return getCharVolatile(o, offset);
1059     }
1060 
1061     /** Acquire version of {@link #getIntVolatile(Object, long)} */
1062     @HotSpotIntrinsicCandidate
1063     public final int getIntAcquire(Object o, long offset) {
1064         return getIntVolatile(o, offset);
1065     }
1066 
1067     /** Acquire version of {@link #getFloatVolatile(Object, long)} */
1068     @HotSpotIntrinsicCandidate
1069     public final float getFloatAcquire(Object o, long offset) {
1070         return getFloatVolatile(o, offset);
1071     }
1072 
1073     /** Acquire version of {@link #getLongVolatile(Object, long)} */
1074     @HotSpotIntrinsicCandidate
1075     public final long getLongAcquire(Object o, long offset) {
1076         return getLongVolatile(o, offset);
1077     }
1078 
1079     /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
1080     @HotSpotIntrinsicCandidate
1081     public final double getDoubleAcquire(Object o, long offset) {
1082         return getDoubleVolatile(o, offset);
1083     }
1084 
1085     /** Release version of {@link #putObjectVolatile(Object, long, Object)} */
1086     @HotSpotIntrinsicCandidate
1087     public final void putObjectRelease(Object o, long offset, Object x) {
1088         putObjectVolatile(o, offset, x);
1089     }
1090 
1091     /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
1092     @HotSpotIntrinsicCandidate
1093     public final void putBooleanRelease(Object o, long offset, boolean x) {
1094         putBooleanVolatile(o, offset, x);
1095     }
1096 
1097     /** Release version of {@link #putByteVolatile(Object, long, byte)} */
1098     @HotSpotIntrinsicCandidate
1099     public final void putByteRelease(Object o, long offset, byte x) {
1100         putByteVolatile(o, offset, x);
1101     }
1102 
1103     /** Release version of {@link #putShortVolatile(Object, long, short)} */
1104     @HotSpotIntrinsicCandidate
1105     public final void putShortRelease(Object o, long offset, short x) {
1106         putShortVolatile(o, offset, x);
1107     }
1108 
1109     /** Release version of {@link #putCharVolatile(Object, long, char)} */
1110     @HotSpotIntrinsicCandidate
1111     public final void putCharRelease(Object o, long offset, char x) {
1112         putCharVolatile(o, offset, x);
1113     }
1114 
1115     /** Release version of {@link #putIntVolatile(Object, long, int)} */
1116     @HotSpotIntrinsicCandidate
1117     public final void putIntRelease(Object o, long offset, int x) {
1118         putIntVolatile(o, offset, x);
1119     }
1120 
1121     /** Release version of {@link #putFloatVolatile(Object, long, float)} */
1122     @HotSpotIntrinsicCandidate
1123     public final void putFloatRelease(Object o, long offset, float x) {
1124         putFloatVolatile(o, offset, x);
1125     }
1126 
1127     /** Release version of {@link #putLongVolatile(Object, long, long)} */
1128     @HotSpotIntrinsicCandidate
1129     public final void putLongRelease(Object o, long offset, long x) {
1130         putLongVolatile(o, offset, x);
1131     }
1132 
1133     /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
1134     @HotSpotIntrinsicCandidate
1135     public final void putDoubleRelease(Object o, long offset, double x) {
1136         putDoubleVolatile(o, offset, x);
1137     }
1138 
1139     // ------------------------------ Opaque --------------------------------------
1140 
1141     /** Opaque version of {@link #getObjectVolatile(Object, long)} */
1142     @HotSpotIntrinsicCandidate
1143     public final Object getObjectOpaque(Object o, long offset) {
1144         return getObjectVolatile(o, offset);
1145     }
1146 
1147     /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
1148     @HotSpotIntrinsicCandidate
1149     public final boolean getBooleanOpaque(Object o, long offset) {
1150         return getBooleanVolatile(o, offset);
1151     }
1152 
1153     /** Opaque version of {@link #getByteVolatile(Object, long)} */
1154     @HotSpotIntrinsicCandidate
1155     public final byte getByteOpaque(Object o, long offset) {
1156         return getByteVolatile(o, offset);
1157     }
1158 
1159     /** Opaque version of {@link #getShortVolatile(Object, long)} */
1160     @HotSpotIntrinsicCandidate
1161     public final short getShortOpaque(Object o, long offset) {
1162         return getShortVolatile(o, offset);
1163     }
1164 
1165     /** Opaque version of {@link #getCharVolatile(Object, long)} */
1166     @HotSpotIntrinsicCandidate
1167     public final char getCharOpaque(Object o, long offset) {
1168         return getCharVolatile(o, offset);
1169     }
1170 
1171     /** Opaque version of {@link #getIntVolatile(Object, long)} */
1172     @HotSpotIntrinsicCandidate
1173     public final int getIntOpaque(Object o, long offset) {
1174         return getIntVolatile(o, offset);
1175     }
1176 
1177     /** Opaque version of {@link #getFloatVolatile(Object, long)} */
1178     @HotSpotIntrinsicCandidate
1179     public final float getFloatOpaque(Object o, long offset) {
1180         return getFloatVolatile(o, offset);
1181     }
1182 
1183     /** Opaque version of {@link #getLongVolatile(Object, long)} */
1184     @HotSpotIntrinsicCandidate
1185     public final long getLongOpaque(Object o, long offset) {
1186         return getLongVolatile(o, offset);
1187     }
1188 
1189     /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
1190     @HotSpotIntrinsicCandidate
1191     public final double getDoubleOpaque(Object o, long offset) {
1192         return getDoubleVolatile(o, offset);
1193     }
1194 
1195     /** Opaque version of {@link #putObjectVolatile(Object, long, Object)} */
1196     @HotSpotIntrinsicCandidate
1197     public final void putObjectOpaque(Object o, long offset, Object x) {
1198         putObjectVolatile(o, offset, x);
1199     }
1200 
1201     /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
1202     @HotSpotIntrinsicCandidate
1203     public final void putBooleanOpaque(Object o, long offset, boolean x) {
1204         putBooleanVolatile(o, offset, x);
1205     }
1206 
1207     /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
1208     @HotSpotIntrinsicCandidate
1209     public final void putByteOpaque(Object o, long offset, byte x) {
1210         putByteVolatile(o, offset, x);
1211     }
1212 
1213     /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
1214     @HotSpotIntrinsicCandidate
1215     public final void putShortOpaque(Object o, long offset, short x) {
1216         putShortVolatile(o, offset, x);
1217     }
1218 
1219     /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
1220     @HotSpotIntrinsicCandidate
1221     public final void putCharOpaque(Object o, long offset, char x) {
1222         putCharVolatile(o, offset, x);
1223     }
1224 
1225     /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
1226     @HotSpotIntrinsicCandidate
1227     public final void putIntOpaque(Object o, long offset, int x) {
1228         putIntVolatile(o, offset, x);
1229     }
1230 
1231     /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
1232     @HotSpotIntrinsicCandidate
1233     public final void putFloatOpaque(Object o, long offset, float x) {
1234         putFloatVolatile(o, offset, x);
1235     }
1236 
1237     /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
1238     @HotSpotIntrinsicCandidate
1239     public final void putLongOpaque(Object o, long offset, long x) {
1240         putLongVolatile(o, offset, x);
1241     }
1242 
1243     /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
1244     @HotSpotIntrinsicCandidate
1245     public final void putDoubleOpaque(Object o, long offset, double x) {
1246         putDoubleVolatile(o, offset, x);
1247     }
1248 
1249     /**
1250      * Unblocks the given thread blocked on {@code park}, or, if it is
1251      * not blocked, causes the subsequent call to {@code park} not to
1252      * block.  Note: this operation is "unsafe" solely because the
1253      * caller must somehow ensure that the thread has not been
1254      * destroyed. Nothing special is usually required to ensure this
1255      * when called from Java (in which there will ordinarily be a live
1256      * reference to the thread) but this is not nearly-automatically
1257      * so when calling from native code.
1258      *
1259      * @param thread the thread to unpark.
1260      */
1261     @HotSpotIntrinsicCandidate
1262     public native void unpark(Object thread);
1263 
1264     /**
1265      * Blocks current thread, returning when a balancing
1266      * {@code unpark} occurs, or a balancing {@code unpark} has
1267      * already occurred, or the thread is interrupted, or, if not
1268      * absolute and time is not zero, the given time nanoseconds have
1269      * elapsed, or if absolute, the given deadline in milliseconds
1270      * since Epoch has passed, or spuriously (i.e., returning for no
1271      * "reason"). Note: This operation is in the Unsafe class only
1272      * because {@code unpark} is, so it would be strange to place it
1273      * elsewhere.
1274      */
1275     @HotSpotIntrinsicCandidate
1276     public native void park(boolean isAbsolute, long time);
1277 
1278     /**
1279      * Gets the load average in the system run queue assigned
1280      * to the available processors averaged over various periods of time.
1281      * This method retrieves the given {@code nelem} samples and
1282      * assigns to the elements of the given {@code loadavg} array.
1283      * The system imposes a maximum of 3 samples, representing
1284      * averages over the last 1,  5,  and  15 minutes, respectively.
1285      *
1286      * @param loadavg an array of double of size nelems
1287      * @param nelems the number of samples to be retrieved and
1288      *        must be 1 to 3.
1289      *
1290      * @return the number of samples actually retrieved; or -1
1291      *         if the load average is unobtainable.
1292      */
1293     public native int getLoadAverage(double[] loadavg, int nelems);
1294 
1295     // The following contain CAS-based Java implementations used on
1296     // platforms not supporting native instructions
1297 
1298     /**
1299      * Atomically adds the given value to the current value of a field
1300      * or array element within the given object {@code o}
1301      * at the given {@code offset}.
1302      *
1303      * @param o object/array to update the field/element in
1304      * @param offset field/element offset
1305      * @param delta the value to add
1306      * @return the previous value
1307      * @since 1.8
1308      */
1309     @HotSpotIntrinsicCandidate
1310     public final int getAndAddInt(Object o, long offset, int delta) {
1311         int v;
1312         do {
1313             v = getIntVolatile(o, offset);
1314         } while (!compareAndSwapInt(o, offset, v, v + delta));
1315         return v;
1316     }
1317 
1318     /**
1319      * Atomically adds the given value to the current value of a field
1320      * or array element within the given object {@code o}
1321      * at the given {@code offset}.
1322      *
1323      * @param o object/array to update the field/element in
1324      * @param offset field/element offset
1325      * @param delta the value to add
1326      * @return the previous value
1327      * @since 1.8
1328      */
1329     @HotSpotIntrinsicCandidate
1330     public final long getAndAddLong(Object o, long offset, long delta) {
1331         long v;
1332         do {
1333             v = getLongVolatile(o, offset);
1334         } while (!compareAndSwapLong(o, offset, v, v + delta));
1335         return v;
1336     }
1337 
1338     /**
1339      * Atomically exchanges the given value with the current value of
1340      * a field or array element within the given object {@code o}
1341      * at the given {@code offset}.
1342      *
1343      * @param o object/array to update the field/element in
1344      * @param offset field/element offset
1345      * @param newValue new value
1346      * @return the previous value
1347      * @since 1.8
1348      */
1349     @HotSpotIntrinsicCandidate
1350     public final int getAndSetInt(Object o, long offset, int newValue) {
1351         int v;
1352         do {
1353             v = getIntVolatile(o, offset);
1354         } while (!compareAndSwapInt(o, offset, v, newValue));
1355         return v;
1356     }
1357 
1358     /**
1359      * Atomically exchanges the given value with the current value of
1360      * a field or array element within the given object {@code o}
1361      * at the given {@code offset}.
1362      *
1363      * @param o object/array to update the field/element in
1364      * @param offset field/element offset
1365      * @param newValue new value
1366      * @return the previous value
1367      * @since 1.8
1368      */
1369     @HotSpotIntrinsicCandidate
1370     public final long getAndSetLong(Object o, long offset, long newValue) {
1371         long v;
1372         do {
1373             v = getLongVolatile(o, offset);
1374         } while (!compareAndSwapLong(o, offset, v, newValue));
1375         return v;
1376     }
1377 
1378     /**
1379      * Atomically exchanges the given reference value with the current
1380      * reference value of a field or array element within the given
1381      * object {@code o} at the given {@code offset}.
1382      *
1383      * @param o object/array to update the field/element in
1384      * @param offset field/element offset
1385      * @param newValue new value
1386      * @return the previous value
1387      * @since 1.8
1388      */
1389     @HotSpotIntrinsicCandidate
1390     public final Object getAndSetObject(Object o, long offset, Object newValue) {
1391         Object v;
1392         do {
1393             v = getObjectVolatile(o, offset);
1394         } while (!compareAndSwapObject(o, offset, v, newValue));
1395         return v;
1396     }
1397 
1398 
1399     /**
1400      * Ensures that loads before the fence will not be reordered with loads and
1401      * stores after the fence; a "LoadLoad plus LoadStore barrier".
1402      *
1403      * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
1404      * (an "acquire fence").
1405      *
1406      * A pure LoadLoad fence is not provided, since the addition of LoadStore
1407      * is almost always desired, and most current hardware instructions that
1408      * provide a LoadLoad barrier also provide a LoadStore barrier for free.
1409      * @since 1.8
1410      */
1411     @HotSpotIntrinsicCandidate
1412     public native void loadFence();
1413 
1414     /**
1415      * Ensures that loads and stores before the fence will not be reordered with
1416      * stores after the fence; a "StoreStore plus LoadStore barrier".
1417      *
1418      * Corresponds to C11 atomic_thread_fence(memory_order_release)
1419      * (a "release fence").
1420      *
1421      * A pure StoreStore fence is not provided, since the addition of LoadStore
1422      * is almost always desired, and most current hardware instructions that
1423      * provide a StoreStore barrier also provide a LoadStore barrier for free.
1424      * @since 1.8
1425      */
1426     @HotSpotIntrinsicCandidate
1427     public native void storeFence();
1428 
1429     /**
1430      * Ensures that loads and stores before the fence will not be reordered
1431      * with loads and stores after the fence.  Implies the effects of both
1432      * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
1433      * barrier.
1434      *
1435      * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
1436      * @since 1.8
1437      */
1438     @HotSpotIntrinsicCandidate
1439     public native void fullFence();
1440 
1441     /**
1442      * Ensures that loads before the fence will not be reordered with
1443      * loads after the fence.
1444      */
1445     public final void loadLoadFence() {
1446         loadFence();
1447     }
1448 
1449     /**
1450      * Ensures that stores before the fence will not be reordered with
1451      * stores after the fence.
1452      */
1453     public final void storeStoreFence() {
1454         storeFence();
1455     }
1456 
1457 
1458     /**
1459      * Throws IllegalAccessError; for use by the VM for access control
1460      * error support.
1461      * @since 1.8
1462      */
1463     private static void throwIllegalAccessError() {
1464         throw new IllegalAccessError();
1465     }
1466 
1467     /**
1468      * @return Returns true if the native byte ordering of this
1469      * platform is big-endian, false if it is little-endian.
1470      */
1471     public final boolean isBigEndian() { return BE; }
1472 
1473     /**
1474      * @return Returns true if this platform is capable of performing
1475      * accesses at addresses which are not aligned for the type of the
1476      * primitive type being accessed, false otherwise.
1477      */
1478     public final boolean unalignedAccess() { return unalignedAccess; }
1479 
1480     /**
1481      * Fetches a value at some byte offset into a given Java object.
1482      * More specifically, fetches a value within the given object
1483      * <code>o</code> at the given offset, or (if <code>o</code> is
1484      * null) from the memory address whose numerical value is the
1485      * given offset.  <p>
1486      *
1487      * The specification of this method is the same as {@link
1488      * #getLong(Object, long)} except that the offset does not need to
1489      * have been obtained from {@link #objectFieldOffset} on the
1490      * {@link java.lang.reflect.Field} of some Java field.  The value
1491      * in memory is raw data, and need not correspond to any Java
1492      * variable.  Unless <code>o</code> is null, the value accessed
1493      * must be entirely within the allocated object.  The endianness
1494      * of the value in memory is the endianness of the native platform.
1495      *
1496      * <p> The read will be atomic with respect to the largest power
1497      * of two that divides the GCD of the offset and the storage size.
1498      * For example, getLongUnaligned will make atomic reads of 2-, 4-,
1499      * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
1500      * respectively.  There are no other guarantees of atomicity.
1501      * <p>
1502      * 8-byte atomicity is only guaranteed on platforms on which
1503      * support atomic accesses to longs.
1504      *
1505      * @param o Java heap object in which the value resides, if any, else
1506      *        null
1507      * @param offset The offset in bytes from the start of the object
1508      * @return the value fetched from the indicated object
1509      * @throws RuntimeException No defined exceptions are thrown, not even
1510      *         {@link NullPointerException}
1511      * @since 9
1512      */
1513     @HotSpotIntrinsicCandidate
1514     public final long getLongUnaligned(Object o, long offset) {
1515         if ((offset & 7) == 0) {
1516             return getLong(o, offset);
1517         } else if ((offset & 3) == 0) {
1518             return makeLong(getInt(o, offset),
1519                             getInt(o, offset + 4));
1520         } else if ((offset & 1) == 0) {
1521             return makeLong(getShort(o, offset),
1522                             getShort(o, offset + 2),
1523                             getShort(o, offset + 4),
1524                             getShort(o, offset + 6));
1525         } else {
1526             return makeLong(getByte(o, offset),
1527                             getByte(o, offset + 1),
1528                             getByte(o, offset + 2),
1529                             getByte(o, offset + 3),
1530                             getByte(o, offset + 4),
1531                             getByte(o, offset + 5),
1532                             getByte(o, offset + 6),
1533                             getByte(o, offset + 7));
1534         }
1535     }
1536     /**
1537      * As {@link #getLongUnaligned(Object, long)} but with an
1538      * additional argument which specifies the endianness of the value
1539      * as stored in memory.
1540      *
1541      * @param o Java heap object in which the variable resides
1542      * @param offset The offset in bytes from the start of the object
1543      * @param bigEndian The endianness of the value
1544      * @return the value fetched from the indicated object
1545      * @since 9
1546      */
1547     public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
1548         return convEndian(bigEndian, getLongUnaligned(o, offset));
1549     }
1550 
1551     /** @see #getLongUnaligned(Object, long) */
1552     @HotSpotIntrinsicCandidate
1553     public final int getIntUnaligned(Object o, long offset) {
1554         if ((offset & 3) == 0) {
1555             return getInt(o, offset);
1556         } else if ((offset & 1) == 0) {
1557             return makeInt(getShort(o, offset),
1558                            getShort(o, offset + 2));
1559         } else {
1560             return makeInt(getByte(o, offset),
1561                            getByte(o, offset + 1),
1562                            getByte(o, offset + 2),
1563                            getByte(o, offset + 3));
1564         }
1565     }
1566     /** @see #getLongUnaligned(Object, long, boolean) */
1567     public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
1568         return convEndian(bigEndian, getIntUnaligned(o, offset));
1569     }
1570 
1571     /** @see #getLongUnaligned(Object, long) */
1572     @HotSpotIntrinsicCandidate
1573     public final short getShortUnaligned(Object o, long offset) {
1574         if ((offset & 1) == 0) {
1575             return getShort(o, offset);
1576         } else {
1577             return makeShort(getByte(o, offset),
1578                              getByte(o, offset + 1));
1579         }
1580     }
1581     /** @see #getLongUnaligned(Object, long, boolean) */
1582     public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
1583         return convEndian(bigEndian, getShortUnaligned(o, offset));
1584     }
1585 
1586     /** @see #getLongUnaligned(Object, long) */
1587     @HotSpotIntrinsicCandidate
1588     public final char getCharUnaligned(Object o, long offset) {
1589         if ((offset & 1) == 0) {
1590             return getChar(o, offset);
1591         } else {
1592             return (char)makeShort(getByte(o, offset),
1593                                    getByte(o, offset + 1));
1594         }
1595     }
1596 
1597     /** @see #getLongUnaligned(Object, long, boolean) */
1598     public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
1599         return convEndian(bigEndian, getCharUnaligned(o, offset));
1600     }
1601 
1602     /**
1603      * Stores a value at some byte offset into a given Java object.
1604      * <p>
1605      * The specification of this method is the same as {@link
1606      * #getLong(Object, long)} except that the offset does not need to
1607      * have been obtained from {@link #objectFieldOffset} on the
1608      * {@link java.lang.reflect.Field} of some Java field.  The value
1609      * in memory is raw data, and need not correspond to any Java
1610      * variable.  The endianness of the value in memory is the
1611      * endianness of the native platform.
1612      * <p>
1613      * The write will be atomic with respect to the largest power of
1614      * two that divides the GCD of the offset and the storage size.
1615      * For example, putLongUnaligned will make atomic writes of 2-, 4-,
1616      * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
1617      * respectively.  There are no other guarantees of atomicity.
1618      * <p>
1619      * 8-byte atomicity is only guaranteed on platforms on which
1620      * support atomic accesses to longs.
1621      *
1622      * @param o Java heap object in which the value resides, if any, else
1623      *        null
1624      * @param offset The offset in bytes from the start of the object
1625      * @param x the value to store
1626      * @throws RuntimeException No defined exceptions are thrown, not even
1627      *         {@link NullPointerException}
1628      * @since 9
1629      */
1630     @HotSpotIntrinsicCandidate
1631     public final void putLongUnaligned(Object o, long offset, long x) {
1632         if ((offset & 7) == 0) {
1633             putLong(o, offset, x);
1634         } else if ((offset & 3) == 0) {
1635             putLongParts(o, offset,
1636                          (int)(x >> 0),
1637                          (int)(x >>> 32));
1638         } else if ((offset & 1) == 0) {
1639             putLongParts(o, offset,
1640                          (short)(x >>> 0),
1641                          (short)(x >>> 16),
1642                          (short)(x >>> 32),
1643                          (short)(x >>> 48));
1644         } else {
1645             putLongParts(o, offset,
1646                          (byte)(x >>> 0),
1647                          (byte)(x >>> 8),
1648                          (byte)(x >>> 16),
1649                          (byte)(x >>> 24),
1650                          (byte)(x >>> 32),
1651                          (byte)(x >>> 40),
1652                          (byte)(x >>> 48),
1653                          (byte)(x >>> 56));
1654         }
1655     }
1656 
1657     /**
1658      * As {@link #putLongUnaligned(Object, long, long)} but with an additional
1659      * argument which specifies the endianness of the value as stored in memory.
1660      * @param o Java heap object in which the value resides
1661      * @param offset The offset in bytes from the start of the object
1662      * @param x the value to store
1663      * @param bigEndian The endianness of the value
1664      * @throws RuntimeException No defined exceptions are thrown, not even
1665      *         {@link NullPointerException}
1666      * @since 9
1667      */
1668     public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
1669         putLongUnaligned(o, offset, convEndian(bigEndian, x));
1670     }
1671 
1672     /** @see #putLongUnaligned(Object, long, long) */
1673     @HotSpotIntrinsicCandidate
1674     public final void putIntUnaligned(Object o, long offset, int x) {
1675         if ((offset & 3) == 0) {
1676             putInt(o, offset, x);
1677         } else if ((offset & 1) == 0) {
1678             putIntParts(o, offset,
1679                         (short)(x >> 0),
1680                         (short)(x >>> 16));
1681         } else {
1682             putIntParts(o, offset,
1683                         (byte)(x >>> 0),
1684                         (byte)(x >>> 8),
1685                         (byte)(x >>> 16),
1686                         (byte)(x >>> 24));
1687         }
1688     }
1689     /** @see #putLongUnaligned(Object, long, long, boolean) */
1690     public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
1691         putIntUnaligned(o, offset, convEndian(bigEndian, x));
1692     }
1693 
1694     /** @see #putLongUnaligned(Object, long, long) */
1695     @HotSpotIntrinsicCandidate
1696     public final void putShortUnaligned(Object o, long offset, short x) {
1697         if ((offset & 1) == 0) {
1698             putShort(o, offset, x);
1699         } else {
1700             putShortParts(o, offset,
1701                           (byte)(x >>> 0),
1702                           (byte)(x >>> 8));
1703         }
1704     }
1705     /** @see #putLongUnaligned(Object, long, long, boolean) */
1706     public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
1707         putShortUnaligned(o, offset, convEndian(bigEndian, x));
1708     }
1709 
1710     /** @see #putLongUnaligned(Object, long, long) */
1711     @HotSpotIntrinsicCandidate
1712     public final void putCharUnaligned(Object o, long offset, char x) {
1713         putShortUnaligned(o, offset, (short)x);
1714     }
1715     /** @see #putLongUnaligned(Object, long, long, boolean) */
1716     public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
1717         putCharUnaligned(o, offset, convEndian(bigEndian, x));
1718     }
1719 
1720     // JVM interface methods
1721     private native boolean unalignedAccess0();
1722     private native boolean isBigEndian0();
1723 
1724     // BE is true iff the native endianness of this platform is big.
1725     private static final boolean BE = theUnsafe.isBigEndian0();
1726 
1727     // unalignedAccess is true iff this platform can perform unaligned accesses.
1728     private static final boolean unalignedAccess = theUnsafe.unalignedAccess0();
1729 
1730     private static int pickPos(int top, int pos) { return BE ? top - pos : pos; }
1731 
1732     // These methods construct integers from bytes.  The byte ordering
1733     // is the native endianness of this platform.
1734     private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
1735         return ((toUnsignedLong(i0) << pickPos(56, 0))
1736               | (toUnsignedLong(i1) << pickPos(56, 8))
1737               | (toUnsignedLong(i2) << pickPos(56, 16))
1738               | (toUnsignedLong(i3) << pickPos(56, 24))
1739               | (toUnsignedLong(i4) << pickPos(56, 32))
1740               | (toUnsignedLong(i5) << pickPos(56, 40))
1741               | (toUnsignedLong(i6) << pickPos(56, 48))
1742               | (toUnsignedLong(i7) << pickPos(56, 56)));
1743     }
1744     private static long makeLong(short i0, short i1, short i2, short i3) {
1745         return ((toUnsignedLong(i0) << pickPos(48, 0))
1746               | (toUnsignedLong(i1) << pickPos(48, 16))
1747               | (toUnsignedLong(i2) << pickPos(48, 32))
1748               | (toUnsignedLong(i3) << pickPos(48, 48)));
1749     }
1750     private static long makeLong(int i0, int i1) {
1751         return (toUnsignedLong(i0) << pickPos(32, 0))
1752              | (toUnsignedLong(i1) << pickPos(32, 32));
1753     }
1754     private static int makeInt(short i0, short i1) {
1755         return (toUnsignedInt(i0) << pickPos(16, 0))
1756              | (toUnsignedInt(i1) << pickPos(16, 16));
1757     }
1758     private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
1759         return ((toUnsignedInt(i0) << pickPos(24, 0))
1760               | (toUnsignedInt(i1) << pickPos(24, 8))
1761               | (toUnsignedInt(i2) << pickPos(24, 16))
1762               | (toUnsignedInt(i3) << pickPos(24, 24)));
1763     }
1764     private static short makeShort(byte i0, byte i1) {
1765         return (short)((toUnsignedInt(i0) << pickPos(8, 0))
1766                      | (toUnsignedInt(i1) << pickPos(8, 8)));
1767     }
1768 
1769     private static byte  pick(byte  le, byte  be) { return BE ? be : le; }
1770     private static short pick(short le, short be) { return BE ? be : le; }
1771     private static int   pick(int   le, int   be) { return BE ? be : le; }
1772 
1773     // These methods write integers to memory from smaller parts
1774     // provided by their caller.  The ordering in which these parts
1775     // are written is the native endianness of this platform.
1776     private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
1777         putByte(o, offset + 0, pick(i0, i7));
1778         putByte(o, offset + 1, pick(i1, i6));
1779         putByte(o, offset + 2, pick(i2, i5));
1780         putByte(o, offset + 3, pick(i3, i4));
1781         putByte(o, offset + 4, pick(i4, i3));
1782         putByte(o, offset + 5, pick(i5, i2));
1783         putByte(o, offset + 6, pick(i6, i1));
1784         putByte(o, offset + 7, pick(i7, i0));
1785     }
1786     private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
1787         putShort(o, offset + 0, pick(i0, i3));
1788         putShort(o, offset + 2, pick(i1, i2));
1789         putShort(o, offset + 4, pick(i2, i1));
1790         putShort(o, offset + 6, pick(i3, i0));
1791     }
1792     private void putLongParts(Object o, long offset, int i0, int i1) {
1793         putInt(o, offset + 0, pick(i0, i1));
1794         putInt(o, offset + 4, pick(i1, i0));
1795     }
1796     private void putIntParts(Object o, long offset, short i0, short i1) {
1797         putShort(o, offset + 0, pick(i0, i1));
1798         putShort(o, offset + 2, pick(i1, i0));
1799     }
1800     private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
1801         putByte(o, offset + 0, pick(i0, i3));
1802         putByte(o, offset + 1, pick(i1, i2));
1803         putByte(o, offset + 2, pick(i2, i1));
1804         putByte(o, offset + 3, pick(i3, i0));
1805     }
1806     private void putShortParts(Object o, long offset, byte i0, byte i1) {
1807         putByte(o, offset + 0, pick(i0, i1));
1808         putByte(o, offset + 1, pick(i1, i0));
1809     }
1810 
1811     // Zero-extend an integer
1812     private static int toUnsignedInt(byte n)    { return n & 0xff; }
1813     private static int toUnsignedInt(short n)   { return n & 0xffff; }
1814     private static long toUnsignedLong(byte n)  { return n & 0xffl; }
1815     private static long toUnsignedLong(short n) { return n & 0xffffl; }
1816     private static long toUnsignedLong(int n)   { return n & 0xffffffffl; }
1817 
1818     // Maybe byte-reverse an integer
1819     private static char convEndian(boolean big, char n)   { return big == BE ? n : Character.reverseBytes(n); }
1820     private static short convEndian(boolean big, short n) { return big == BE ? n : Short.reverseBytes(n)    ; }
1821     private static int convEndian(boolean big, int n)     { return big == BE ? n : Integer.reverseBytes(n)  ; }
1822     private static long convEndian(boolean big, long n)   { return big == BE ? n : Long.reverseBytes(n)     ; }
1823 }
--- EOF ---