diff -u -r1.1.2.1 -r1.1.2.2
--- IndexBlock.java	20 Oct 2009 23:18:21 -0000	1.1.2.1
+++ IndexBlock.java	27 Oct 2009 23:39:06 -0000	1.1.2.2
@@ -9,6 +9,7 @@

 import hep.lcio.event.LCRunHeader;
 import java.io.IOException;
 import java.util.ArrayList;

+import java.util.Collections;

 import java.util.List;
 
 /**

@@ -152,6 +153,20 @@

         return nRunHeaders;
     }
 

diff -u -r1.16.10.1 -r1.16.10.2
--- SIOLCReader.java	20 Oct 2009 23:18:21 -0000	1.16.10.1
+++ SIOLCReader.java	27 Oct 2009 23:39:06 -0000	1.16.10.2
@@ -16,22 +16,23 @@

 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;

+import java.util.HashMap;

 import java.util.List;

+import java.util.Map;

 
 
 /**
  *
  * @author Tony Johnson

- * @version $Id: SIOLCReader.java,v 1.16.10.1 2009/10/20 23:18:21 tonyj Exp $

+ * @version $Id: SIOLCReader.java,v 1.16.10.2 2009/10/27 23:39:06 tonyj Exp $

  */
 class SIOLCReader implements LCReader
 {
    private List eventListeners = new ArrayList();
    private List runListeners = new ArrayList();

-   private RandomAccessBlock fileRandomAccessBlock;
-   private List<RandomAccessBlock> indexRandomAccessBlocks = new ArrayList<RandomAccessBlock>();

    private SIOReader reader;

-   private boolean indexBlocksRead;

+   private RandomAccessSupport randomAccess;
+   private long lastRecordPosition;

 
    private String[] _filenames ;
    private int _currentIndex ;

@@ -44,6 +45,7 @@

    public void open(String filename) throws IOException
    {
       reader = new SIOReader(filename);

+      randomAccess = new RandomAccessSupport(reader);

    }
 
     /** Opens a list of files for reading (read-only). All subsequent

@@ -98,7 +100,7 @@

          {
             SIORecord record = reader.readRecord();
             String name = record.getRecordName();

-            if (name.equals("LCIORandomAccess")) addRandomAccessRecord(record);

+            if (name.equals("LCIORandomAccess")) randomAccess.addRandomAccessRecord(record);

             if (!name.equals(SIOFactory.eventHeaderRecordName))
                continue;
 

@@ -118,23 +120,24 @@

       }
    }
 

-   public void skipNEvents(int n) 

+   public void skipNEvents(int n) throws IOException

    {

-      int nEvents = 0 ;
-	  try
-	  {
-	     while( nEvents < n )
-	     {
-		    SIORecord record = reader.readRecord();
-		    String name = record.getRecordName();
-		    if ( ! name.equals( SIOFactory.eventHeaderRecordName) )
-			   continue;
-             ++nEvents ;
-	     }
-	  }
-	  catch (IOException x)
-	  {
- 	  }

+      if (randomAccess != null)
+      {
+
+      }
+      else
+      {
+          int nEvents = 0;
+          while( nEvents < n )
+          {
+            SIORecord record = reader.readRecord();
+            String name = record.getRecordName();
+            if ( ! name.equals( SIOFactory.eventHeaderRecordName) )
+               continue;
+            ++nEvents ;
+          }
+      }

    }
    public LCEvent readNextEvent() throws IOException
    {

@@ -148,33 +151,54 @@

 
    public LCRunHeader readNextRunHeader(int accessMode) throws IOException
    {

-      try

+      if (randomAccess != null)

       {

-         for (;;)

+         long position = randomAccess.findNextRunHeader(lastRecordPosition);
+         if (position < 0) return null;
+         else

          {

-            SIORecord record = reader.readRecord();
-            String name = record.getRecordName();
-            if (!name.equals(SIOFactory.runRecordName))
-               continue;
-

+            SIORecord record = reader.readRecord(position);
+            lastRecordPosition = position;

             SIOBlock block = record.getBlock();

-			int major = block.getMajorVersion() ;
-			int minor = block.getMinorVersion() ;
-			if (( major < 1) && ( minor < 8))

+            int major = block.getMajorVersion() ;
+            int minor = block.getMinorVersion() ;
+            if (( major < 1) && ( minor < 8))

                throw new IOException("Sorry: files created with versions older than v00-08" + " are no longer supported !");
 

-	    // FIX ME: need to set access mode here....

+            // FIX ME: need to set access mode here....

             return new SIORunHeader(block.getData(),major,minor);
          }
       }

-      catch (EOFException x)

+      else

       {

-	if( _filenames != null  && ++_currentIndex < _filenames.length ){
-	    close() ;
-	    open( _filenames[ _currentIndex ] ) ;
-	    return readNextRunHeader( accessMode ) ;
-	} 
-         return null;

+          try
+          {
+             for (;;)
+             {
+                SIORecord record = reader.readRecord();
+                String name = record.getRecordName();
+                if (!name.equals(SIOFactory.runRecordName))
+                   continue;
+
+                SIOBlock block = record.getBlock();
+                int major = block.getMajorVersion() ;
+                int minor = block.getMinorVersion() ;
+                if (( major < 1) && ( minor < 8))
+                   throw new IOException("Sorry: files created with versions older than v00-08" + " are no longer supported !");
+
+                // FIX ME: need to set access mode here....
+                return new SIORunHeader(block.getData(),major,minor);
+             }
+          }
+          catch (EOFException x)
+          {
+            if( _filenames != null  && ++_currentIndex < _filenames.length ){
+                close() ;
+                open( _filenames[ _currentIndex ] ) ;
+                return readNextRunHeader( accessMode ) ;
+            }
+             return null;
+          }

       }
    }
 

@@ -261,58 +285,89 @@

       runListeners.remove(ls);
    }
 

-   private void addRandomAccessRecord(SIORecord record) throws IOException
-   {
-      RandomAccessBlock ra = new RandomAccessBlock(record);
-      System.out.println("Found ra="+ra);
-      if (ra.getIndexLocation() == 0) fileRandomAccessBlock = ra;
-      else indexRandomAccessBlocks.add(ra);
-   }

+    private static class RandomAccessSupport {

-   private long findNextRunHeader() throws IOException {
-      RandomAccessBlock fab = findFileRandomAccessBlock();
-      for (RandomAccessBlock rab : findIndexRandomAccessBlocks()) {
-          
-      }
-   }

+        private RandomAccessBlock fileRandomAccessBlock;
+        private List<RandomAccessBlock> indexRandomAccessBlocks = new ArrayList<RandomAccessBlock>();
+        private boolean indexBlocksRead;
+        private SIOReader reader;
+        private Map<RandomAccessBlock,IndexBlock> indexHash = new HashMap<RandomAccessBlock,IndexBlock>();

-   private long findEvent(int run, int event) throws IOException {
-      if (!indexBlocksRead) readIndexBlocks();
-      // FIXME: Assumes records are ordered
-      RunEvent re = new RunEvent(run,event);
-      if (!fileRandomAccessBlock.contains(re)) return -1;
-
-      int location = Collections.binarySearch(indexRandomAccessBlocks,re);
-      return 0;
-   }
-
-    private void readIndexBlocks() throws IOException {
-       RandomAccessBlock fab = findFileRandomAccessBlock();
-
-       if (indexRandomAccessBlocks.isEmpty()) {
-           SIORecord record = reader.readRecord(fab.getPreviousLocation());
-           RandomAccessBlock rab = new RandomAccessBlock(record);
-           indexRandomAccessBlocks.add(rab);
-           indexBlocksRead =  rab.getNextLocation() == 0;
-       }
-       while (!indexBlocksRead) {
-           long nextLocation = indexRandomAccessBlocks.get(indexRandomAccessBlocks.size()-1).getNextLocation();
-           SIORecord record = reader.readRecord(nextLocation);
-           RandomAccessBlock rab = new RandomAccessBlock(record);
-           indexRandomAccessBlocks.add(rab);
-           indexBlocksRead =  rab.getNextLocation() == 0;
-       }
-    }

+        RandomAccessSupport(SIOReader reader) {
+            this.reader = reader;
+        }

-    private RandomAccessBlock findFileRandomAccessBlock() throws IOException {
-        if (fileRandomAccessBlock == null) {
-           SIORecord record = reader.readRecord(0);
-           fileRandomAccessBlock = new RandomAccessBlock(record);