Index: lucene/misc/src/java/org/apache/lucene/index/sorter/Sorter.java
===================================================================
--- lucene/misc/src/java/org/apache/lucene/index/sorter/Sorter.java	(revision 1466021)
+++ lucene/misc/src/java/org/apache/lucene/index/sorter/Sorter.java	(working copy)
@@ -73,6 +73,35 @@
 
   }
 
+  /** Sorts documents in reverse order of a wrapped {@link Sorter}. */
+  public static class ReverseOrderSorter extends Sorter {
+
+    private final Sorter in;
+    
+    public ReverseOrderSorter(Sorter in) {
+      if (in == REVERSE_DOCS || in instanceof ReverseOrderSorter) {
+        throw new IllegalArgumentException("reversing the order of a reversing sorter doesn't make any sense!");
+      }
+      this.in = in;
+    }
+    
+    @Override
+    public DocMap sort(final AtomicReader reader) throws IOException {
+      final int maxDoc = reader.maxDoc();
+      final DocMap inMap = in.sort(reader);
+      return new DocMap() {
+        @Override
+        public int oldToNew(int docID) {
+          return maxDoc - inMap.oldToNew(docID) - 1;
+        }
+        @Override
+        public int newToOld(int docID) {
+          return maxDoc - inMap.newToOld(docID) - 1;
+        }
+      };
+    }
+  }
+
   /** Sorts documents in reverse order. */
   public static final Sorter REVERSE_DOCS = new Sorter() {
     @Override
@@ -90,7 +119,7 @@
       };
     }
   };
-
+  
   private static final class DocValueSorterTemplate extends SorterTemplate {
     
     private final int[] docs;