1 /*
   2  * Copyright (c) 2000, 2015, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.gc.shared;
  26 
  27 import java.io.*;
  28 import java.util.*;
  29 
  30 import sun.jvm.hotspot.debugger.*;
  31 import sun.jvm.hotspot.memory.*;
  32 import sun.jvm.hotspot.runtime.*;
  33 import sun.jvm.hotspot.types.*;
  34 
  35 public class ContiguousSpace extends CompactibleSpace implements LiveRegionsProvider {
  36   private static AddressField topField;
  37 
  38   static {
  39     VM.registerVMInitializedObserver(new Observer() {
  40         public void update(Observable o, Object data) {
  41           initialize(VM.getVM().getTypeDataBase());
  42         }
  43       });
  44   }
  45 
  46   private static synchronized void initialize(TypeDataBase db) {
  47     Type type = db.lookupType("ContiguousSpace");
  48 
  49     topField = type.getAddressField("_top");
  50   }
  51 
  52   public ContiguousSpace(Address addr) {
  53     super(addr);
  54   }
  55 
  56   public Address top() {
  57     return topField.getValue(addr);
  58   }
  59 
  60   /** In bytes */
  61   public long capacity() {
  62     return end().minus(bottom());
  63   }
  64 
  65   /** In bytes */
  66   public long used() {
  67     return top().minus(bottom());
  68   }
  69 
  70   /** In bytes */
  71   public long free() {
  72     return end().minus(top());
  73   }
  74 
  75   /** In a contiguous space we have a more obvious bound on what parts
  76       contain objects. */
  77   public MemRegion usedRegion() {
  78     return new MemRegion(bottom(), top());
  79   }
  80 
  81   /** Returns regions of Space where live objects live */
  82   public List<MemRegion> getLiveRegions() {
  83     List<MemRegion> res = new ArrayList<>();
  84     res.add(new MemRegion(bottom(), top()));
  85     return res;
  86   }
  87 
  88   /** Testers */
  89   public boolean contains(Address p) {
  90     return (bottom().lessThanOrEqual(p) && top().greaterThan(p));
  91   }
  92 
  93   public void printOn(PrintStream tty) {
  94     tty.print(" [" + bottom() + "," +
  95                 top() + "," + end() + ")");
  96     super.printOn(tty);
  97   }
  98 }