--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/src/share/classes/sun/jvm/hotspot/debugger/MappedByteBufferDataSource.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2002 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+package sun.jvm.hotspot.debugger;
+
+import java.io.*;
+import java.nio.*;
+
+/** Implementation of DataSource using MappedByteBuffer. This works
+    around a performance problem in JDK 1.4 where ByteBuffer's
+    operations always become virtual calls rather than being inlined.
+    Need to fix this soon. */
+
+public class MappedByteBufferDataSource implements DataSource {
+  private MappedByteBuffer buf;
+
+  public MappedByteBufferDataSource(MappedByteBuffer buf) {
+    this.buf = buf;
+  }
+
+  public byte  readByte()       throws IOException { return buf.get();            }
+  public short readShort()      throws IOException { return buf.getShort();       }
+  public int   readInt()        throws IOException { return buf.getInt();         }
+  public long  readLong()       throws IOException { return buf.getLong();        }
+  public int   read(byte[] b)   throws IOException { buf.get(b); return b.length; }
+  public void  seek(long pos)   throws IOException {
+    try {
+      buf.position((int) pos);
+    } catch (IllegalArgumentException e) {
+      System.err.println("Error seeking to file position 0x" + Long.toHexString(pos));
+      throw(e);
+    }
+  }
+  public long  getFilePointer() throws IOException { return buf.position();       }
+  public void  close()          throws IOException { buf = null;                  }
+}