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src/java.base/share/classes/java/nio/Buffer.java

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rev 58228 : 8238665: Add JFR event for direct memory statistics


  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 java.nio;
  27 
  28 import jdk.internal.HotSpotIntrinsicCandidate;
  29 import jdk.internal.access.JavaNioAccess;
  30 import jdk.internal.access.SharedSecrets;
  31 import jdk.internal.access.foreign.MemorySegmentProxy;
  32 import jdk.internal.misc.Unsafe;

  33 import jdk.internal.vm.annotation.ForceInline;
  34 
  35 import java.util.Spliterator;
  36 
  37 /**
  38  * A container for data of a specific primitive type.
  39  *
  40  * <p> A buffer is a linear, finite sequence of elements of a specific
  41  * primitive type.  Aside from its content, the essential properties of a
  42  * buffer are its capacity, limit, and position: </p>
  43  *
  44  * <blockquote>
  45  *
  46  *   <p> A buffer's <i>capacity</i> is the number of elements it contains.  The
  47  *   capacity of a buffer is never negative and never changes.  </p>
  48  *
  49  *   <p> A buffer's <i>limit</i> is the index of the first element that should
  50  *   not be read or written.  A buffer's limit is never negative and is never
  51  *   greater than its capacity.  </p>
  52  *


 741     final int markValue() {                             // package-private
 742         return mark;
 743     }
 744 
 745     final void discardMark() {                          // package-private
 746         mark = -1;
 747     }
 748 
 749     @ForceInline
 750     final void checkSegment() {
 751         if (segment != null) {
 752             segment.checkValidState();
 753         }
 754     }
 755 
 756     static {
 757         // setup access to this package in SharedSecrets
 758         SharedSecrets.setJavaNioAccess(
 759             new JavaNioAccess() {
 760                 @Override
 761                 public JavaNioAccess.BufferPool getDirectBufferPool() {
 762                     return Bits.BUFFER_POOL;
 763                 }
 764 
 765                 @Override
 766                 public ByteBuffer newDirectByteBuffer(long addr, int cap, Object obj, MemorySegmentProxy segment) {
 767                     return new DirectByteBuffer(addr, cap, obj, segment);
 768                 }
 769 
 770                 @Override
 771                 public ByteBuffer newHeapByteBuffer(byte[] hb, int offset, int capacity, MemorySegmentProxy segment) {
 772                     return new HeapByteBuffer(hb, offset, capacity, segment);
 773                 }
 774 
 775                 @Override
 776                 public Object getBufferBase(ByteBuffer bb) {
 777                     return bb.base();
 778                 }
 779 
 780                 @Override
 781                 public long getBufferAddress(ByteBuffer bb) {


  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 java.nio;
  27 
  28 import jdk.internal.HotSpotIntrinsicCandidate;
  29 import jdk.internal.access.JavaNioAccess;
  30 import jdk.internal.access.SharedSecrets;
  31 import jdk.internal.access.foreign.MemorySegmentProxy;
  32 import jdk.internal.misc.Unsafe;
  33 import jdk.internal.misc.VM.BufferPool;
  34 import jdk.internal.vm.annotation.ForceInline;
  35 
  36 import java.util.Spliterator;
  37 
  38 /**
  39  * A container for data of a specific primitive type.
  40  *
  41  * <p> A buffer is a linear, finite sequence of elements of a specific
  42  * primitive type.  Aside from its content, the essential properties of a
  43  * buffer are its capacity, limit, and position: </p>
  44  *
  45  * <blockquote>
  46  *
  47  *   <p> A buffer's <i>capacity</i> is the number of elements it contains.  The
  48  *   capacity of a buffer is never negative and never changes.  </p>
  49  *
  50  *   <p> A buffer's <i>limit</i> is the index of the first element that should
  51  *   not be read or written.  A buffer's limit is never negative and is never
  52  *   greater than its capacity.  </p>
  53  *


 742     final int markValue() {                             // package-private
 743         return mark;
 744     }
 745 
 746     final void discardMark() {                          // package-private
 747         mark = -1;
 748     }
 749 
 750     @ForceInline
 751     final void checkSegment() {
 752         if (segment != null) {
 753             segment.checkValidState();
 754         }
 755     }
 756 
 757     static {
 758         // setup access to this package in SharedSecrets
 759         SharedSecrets.setJavaNioAccess(
 760             new JavaNioAccess() {
 761                 @Override
 762                 public BufferPool getDirectBufferPool() {
 763                     return Bits.BUFFER_POOL;
 764                 }
 765 
 766                 @Override
 767                 public ByteBuffer newDirectByteBuffer(long addr, int cap, Object obj, MemorySegmentProxy segment) {
 768                     return new DirectByteBuffer(addr, cap, obj, segment);
 769                 }
 770 
 771                 @Override
 772                 public ByteBuffer newHeapByteBuffer(byte[] hb, int offset, int capacity, MemorySegmentProxy segment) {
 773                     return new HeapByteBuffer(hb, offset, capacity, segment);
 774                 }
 775 
 776                 @Override
 777                 public Object getBufferBase(ByteBuffer bb) {
 778                     return bb.base();
 779                 }
 780 
 781                 @Override
 782                 public long getBufferAddress(ByteBuffer bb) {
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