diff --git a/lucene/src/java/org/apache/lucene/util/packed/Direct16.java b/lucene/src/java/org/apache/lucene/util/packed/Direct16.java
index 962e224cb3c..c698bd6ab1f 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/Direct16.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/Direct16.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
 import java.io.IOException;
@@ -38,7 +38,7 @@ public class Direct16 extends PackedInts.ReaderImpl
     values = new short[valueCount];
   }
 
-  public Direct16(IndexInput in, int valueCount) throws IOException {
+  public Direct16(DataInput in, int valueCount) throws IOException {
     super(valueCount, BITS_PER_VALUE);
     short[] values = new short[valueCount];
     for(int i=0;i<valueCount;i++) {
diff --git a/lucene/src/java/org/apache/lucene/util/packed/Direct32.java b/lucene/src/java/org/apache/lucene/util/packed/Direct32.java
index 8d3486ae6bf..c48d5b07d4c 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/Direct32.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/Direct32.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
 import java.io.IOException;
@@ -38,7 +38,7 @@ public class Direct32 extends PackedInts.ReaderImpl
     values = new int[valueCount];
   }
 
-  public Direct32(IndexInput in, int valueCount) throws IOException {
+  public Direct32(DataInput in, int valueCount) throws IOException {
     super(valueCount, BITS_PER_VALUE);
     int[] values = new int[valueCount];
     for(int i=0;i<valueCount;i++) {
diff --git a/lucene/src/java/org/apache/lucene/util/packed/Direct64.java b/lucene/src/java/org/apache/lucene/util/packed/Direct64.java
index c72abfb6bd8..591483d02b4 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/Direct64.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/Direct64.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
 import java.io.IOException;
@@ -38,7 +38,7 @@ public class Direct64 extends PackedInts.ReaderImpl
     values = new long[valueCount];
   }
 
-  public Direct64(IndexInput in, int valueCount) throws IOException {
+  public Direct64(DataInput in, int valueCount) throws IOException {
     super(valueCount, BITS_PER_VALUE);
     long[] values = new long[valueCount];
     for(int i=0;i<valueCount;i++) {
diff --git a/lucene/src/java/org/apache/lucene/util/packed/Direct8.java b/lucene/src/java/org/apache/lucene/util/packed/Direct8.java
index 233dfe0c310..ab4000418ac 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/Direct8.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/Direct8.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
 import java.io.IOException;
@@ -38,7 +38,7 @@ public class Direct8 extends PackedInts.ReaderImpl
     values = new byte[valueCount];
   }
 
-  public Direct8(IndexInput in, int valueCount)
+  public Direct8(DataInput in, int valueCount)
           throws IOException {
     super(valueCount, BITS_PER_VALUE);
     byte[] values = new byte[valueCount];
diff --git a/lucene/src/java/org/apache/lucene/util/packed/Packed32.java b/lucene/src/java/org/apache/lucene/util/packed/Packed32.java
index ff22ad7ef48..ed7b8fd8b10 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/Packed32.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/Packed32.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
 import java.io.IOException;
@@ -122,14 +122,14 @@ class Packed32 extends PackedInts.ReaderImpl implements PackedInts.Mutable {
   }
 
   /**
-   * Creates an array with content retrieved from the given IndexInput.
-   * @param in       an IndexInput, positioned at the start of Packed64-content.
+   * Creates an array with content retrieved from the given DataInput.
+   * @param in       a DataInput, positioned at the start of Packed64-content.
    * @param valueCount  the number of elements.
    * @param bitsPerValue the number of bits available for any given value.
    * @throws java.io.IOException if the values for the backing array could not
    *                             be retrieved.
    */
-  public Packed32(IndexInput in, int valueCount, int bitsPerValue)
+  public Packed32(DataInput in, int valueCount, int bitsPerValue)
                                                             throws IOException {
     super(valueCount, bitsPerValue);
     int size = size(bitsPerValue, valueCount);
diff --git a/lucene/src/java/org/apache/lucene/util/packed/Packed64.java b/lucene/src/java/org/apache/lucene/util/packed/Packed64.java
index 8428c9e36f2..db407519a2a 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/Packed64.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/Packed64.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.DataInput;
 import org.apache.lucene.util.RamUsageEstimator;
 
 import java.io.IOException;
@@ -141,14 +141,14 @@ class Packed64 extends PackedInts.ReaderImpl implements PackedInts.Mutable {
   }
 
   /**
-   * Creates an array with content retrieved from the given IndexInput.
-   * @param in       an IndexInput, positioned at the start of Packed64-content.
+   * Creates an array with content retrieved from the given DataInput.
+   * @param in       a DataInput, positioned at the start of Packed64-content.
    * @param valueCount  the number of elements.
    * @param bitsPerValue the number of bits available for any given value.
    * @throws java.io.IOException if the values for the backing array could not
    *                             be retrieved.
    */
-  public Packed64(IndexInput in, int valueCount, int bitsPerValue)
+  public Packed64(DataInput in, int valueCount, int bitsPerValue)
                                                             throws IOException {
     super(valueCount, bitsPerValue);
     int size = size(valueCount, bitsPerValue);
diff --git a/lucene/src/java/org/apache/lucene/util/packed/PackedInts.java b/lucene/src/java/org/apache/lucene/util/packed/PackedInts.java
index c7f670c6eaa..589c8bcfe76 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/PackedInts.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/PackedInts.java
@@ -19,7 +19,8 @@ package org.apache.lucene.util.packed;
 
 import java.io.Closeable;
 
-import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.DataInput;
+import org.apache.lucene.store.DataOutput;
 import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.util.CodecUtil;
 import org.apache.lucene.util.Constants;
@@ -134,11 +135,11 @@ public class PackedInts {
    * @lucene.internal
    */
   public static abstract class Writer {
-    protected final IndexOutput out;
+    protected final DataOutput out;
     protected final int bitsPerValue;
     protected final int valueCount;
 
-    protected Writer(IndexOutput out, int valueCount, int bitsPerValue)
+    protected Writer(DataOutput out, int valueCount, int bitsPerValue)
       throws IOException {
       assert bitsPerValue <= 64;
 
@@ -155,14 +156,14 @@ public class PackedInts {
   }
 
   /**
-   * Retrieve PackedInt data from the IndexInput and return a packed int
+   * Retrieve PackedInt data from the DataInput and return a packed int
    * structure based on it.
    * @param in positioned at the beginning of a stored packed int structure.
    * @return a read only random access capable array of positive integers.
    * @throws IOException if the structure could not be retrieved.
    * @lucene.internal
    */
-  public static Reader getReader(IndexInput in) throws IOException {
+  public static Reader getReader(DataInput in) throws IOException {
     CodecUtil.checkHeader(in, CODEC_NAME, VERSION_START, VERSION_START);
     final int bitsPerValue = in.readVInt();
     assert bitsPerValue > 0 && bitsPerValue <= 64: "bitsPerValue=" + bitsPerValue;
@@ -244,7 +245,7 @@ public class PackedInts {
    * @throws IOException if bits could not be written to out.
    * @lucene.internal
    */
-  public static Writer getWriter(IndexOutput out, int valueCount, int bitsPerValue)
+  public static Writer getWriter(DataOutput out, int valueCount, int bitsPerValue)
     throws IOException {
     return new PackedWriter(out, valueCount, bitsPerValue);
   }
diff --git a/lucene/src/java/org/apache/lucene/util/packed/PackedWriter.java b/lucene/src/java/org/apache/lucene/util/packed/PackedWriter.java
index b2c86dd799f..92e361561da 100644
--- a/lucene/src/java/org/apache/lucene/util/packed/PackedWriter.java
+++ b/lucene/src/java/org/apache/lucene/util/packed/PackedWriter.java
@@ -17,7 +17,7 @@ package org.apache.lucene.util.packed;
  * limitations under the License.
  */
 
-import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.store.DataOutput;
 
 import java.io.IOException;
 
@@ -38,7 +38,7 @@ class PackedWriter extends PackedInts.Writer {
   private final long[] masks;
   private int written = 0;
 
-  public PackedWriter(IndexOutput out, int valueCount, int bitsPerValue)
+  public PackedWriter(DataOutput out, int valueCount, int bitsPerValue)
                                                             throws IOException {
     super(out, valueCount, bitsPerValue);