diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetBlockTermState.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetBlockTermState.java
new file mode 100644
index 0000000..bfb4e84
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetBlockTermState.java
@@ -0,0 +1,14 @@
+package org.apache.lucene.codecs.bits;
+
+import org.apache.lucene.codecs.BlockTermState;
+import org.apache.lucene.index.TermState;
+
+class BitSetBlockTermState extends BlockTermState {
+  public long startPostingsPosition;
+
+  @Override
+  public void copyFrom(TermState _other) {
+    super.copyFrom(_other);
+    this.startPostingsPosition = ((BitSetBlockTermState) _other).startPostingsPosition;
+  }
+}
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetCodec.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetCodec.java
new file mode 100644
index 0000000..0773361
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetCodec.java
@@ -0,0 +1,17 @@
+package org.apache.lucene.codecs.bits;
+
+import org.apache.lucene.codecs.FilterCodec;
+import org.apache.lucene.codecs.PostingsFormat;
+import org.apache.lucene.codecs.lucene46.Lucene46Codec;
+
+public class BitSetCodec extends FilterCodec {
+
+  public BitSetCodec() {
+    super("BitSetCodec", new Lucene46Codec());
+  }
+
+  @Override
+  public PostingsFormat postingsFormat() {
+    return new BitSetPostingsFormat();
+  }
+}
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetDocsEnum.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetDocsEnum.java
new file mode 100644
index 0000000..02fae83
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetDocsEnum.java
@@ -0,0 +1,97 @@
+package org.apache.lucene.codecs.bits;
+
+import org.apache.lucene.index.DocsEnum;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.util.Bits;
+
+import java.io.IOException;
+
+class BitSetDocsEnum extends DocsEnum {
+
+  private final long filePosition;
+  private final Bits liveDocs;
+  private final IndexInput pstClone;
+  private final int docCount;
+  private final int postingsListLength;
+
+  private int currentBytePosition = -1;
+  private int readByte = 0;
+  private int docID = -1;
+
+  BitSetDocsEnum(long filePosition, Bits liveDocs, IndexInput pst, int docCount) throws IOException {
+    this.filePosition = filePosition;
+    pstClone = pst.clone();
+    pstClone.seek(filePosition);
+    this.docCount = docCount;
+    this.liveDocs = liveDocs;
+    if ((this.docCount & 0x07) == 0) {
+      postingsListLength = this.docCount >> 3;
+    } else {
+      postingsListLength = (this.docCount >> 3) + 1;
+    }
+    pstClone.seek(filePosition);
+  }
+
+  @Override
+  public int freq() throws IOException {
+    return 1;
+  }
+
+  @Override
+  public int docID() {
+    return docID;
+  }
+
+  @Override
+  public int nextDoc() throws IOException {
+    do {
+      docID++;
+      final int subIndex = docID & 0x7; // index within the readByte
+      if (subIndex == 0) {
+        if (++currentBytePosition == postingsListLength) {
+          return docID = NO_MORE_DOCS;
+        }
+        readByte = pstClone.readByte() & 0xff;
+      }
+      int word = readByte >> subIndex; // skip all the bits to the right of index
+      if (word != 0) {
+        docID = docID + Long.numberOfTrailingZeros(word);
+      } else {
+        while (++currentBytePosition < postingsListLength) {
+          readByte = pstClone.readByte() & 0xff;
+          if (readByte != 0) {
+            docID = (currentBytePosition << 3) + Long.numberOfTrailingZeros(readByte);
+            break;
+          }
+        }
+        if (currentBytePosition == postingsListLength) {
+          return docID = NO_MORE_DOCS;
+        }
+      }
+    } while (!(liveDocs == null || liveDocs.get(docID)));
+    return docID;
+  }
+
+  @Override
+  public int advance(int target) throws IOException {
+    if (docID == NO_MORE_DOCS || target >= docCount) {
+      return docID = NO_MORE_DOCS;
+    }
+    if (target > 0) {
+      docID = target - 1;
+      currentBytePosition = docID >> 3;
+      if ((target & 0x7) != 0) {
+        pstClone.seek(filePosition + currentBytePosition);
+        readByte = pstClone.readByte() & 0xff;
+      } else {
+        pstClone.seek(filePosition + currentBytePosition + 1);
+      }
+    }
+    return nextDoc();
+  }
+
+  @Override
+  public long cost() {
+    return 1;
+  }
+}
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsFileWriter.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsFileWriter.java
new file mode 100644
index 0000000..544d127
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsFileWriter.java
@@ -0,0 +1,69 @@
+package org.apache.lucene.codecs.bits;
+
+import org.apache.lucene.store.IndexOutput;
+
+import java.io.IOException;
+
+class BitSetPostingsFileWriter {
+
+  private static final byte ZERO = 0;
+  private final IndexOutput pst;
+  private final int docCount;
+  private boolean started = false;
+  private int currentWordPosition = 0;
+  private byte word = 0;
+
+  BitSetPostingsFileWriter(int docCount, IndexOutput pst) {
+    this.pst = pst;
+    this.docCount = docCount;
+  }
+
+  void startPostingsList() {
+    if (started) {
+      throw new IllegalStateException("Posting writer was started already");
+    }
+    started = true;
+    currentWordPosition = 0;
+  }
+
+  void finishPostingsList() throws IOException {
+    if (!started) {
+      throw new IllegalStateException("Posting writer was not started");
+    } else {
+      started = false;
+    }
+    currentWordPosition++;
+    pst.writeByte(word);
+    word = 0;
+    int postingsListLength;
+    if ((docCount & 0x07) == 0) {
+      postingsListLength = docCount >> 3;
+    } else {
+      postingsListLength = (docCount >> 3) + 1;
+    }
+    while ((currentWordPosition) <= postingsListLength) {
+      currentWordPosition++;
+      pst.writeByte(ZERO);
+    }
+    pst.flush();
+  }
+
+  void startDoc(int docID) throws IOException {
+    int wordNumber = docID >> 3;
+    int bitPosition = docID & 0x07;
+    if (currentWordPosition < wordNumber) {
+      currentWordPosition++;
+      pst.writeByte(word);
+      while (currentWordPosition < wordNumber) {
+        currentWordPosition++;
+        pst.writeByte(ZERO);
+      }
+      word = 0;
+      word |= (byte) (1 << bitPosition);
+    } else if (wordNumber == currentWordPosition) {
+      word |= (byte) (1 << bitPosition);
+    } else {
+      throw new IllegalArgumentException("Docs must be added in ascending order.");
+    }
+  }
+}
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsFormat.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsFormat.java
new file mode 100644
index 0000000..6b6d49b
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsFormat.java
@@ -0,0 +1,73 @@
+package org.apache.lucene.codecs.bits;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.lucene.codecs.FieldsConsumer;
+import org.apache.lucene.codecs.FieldsProducer;
+import org.apache.lucene.codecs.PostingsFormat;
+import org.apache.lucene.codecs.PostingsReaderBase;
+import org.apache.lucene.codecs.blockterms.BlockTermsReader;
+import org.apache.lucene.codecs.blockterms.BlockTermsWriter;
+import org.apache.lucene.codecs.blockterms.FixedGapTermsIndexReader;
+import org.apache.lucene.codecs.blockterms.FixedGapTermsIndexWriter;
+import org.apache.lucene.codecs.blockterms.TermsIndexReaderBase;
+import org.apache.lucene.codecs.blockterms.TermsIndexWriterBase;
+import org.apache.lucene.index.IndexFileNames;
+import org.apache.lucene.index.SegmentReadState;
+import org.apache.lucene.index.SegmentWriteState;
+import org.apache.lucene.util.BytesRef;
+
+import java.io.IOException;
+
+public class BitSetPostingsFormat extends PostingsFormat {
+
+  static final String POSTINGS_EXTENSION = "pst";
+
+  public BitSetPostingsFormat() {
+    super("BitSetPostingsFormat");
+  }
+
+  static String getPostingsFileName(String segment, String segmentSuffix) {
+    return IndexFileNames.segmentFileName(segment, segmentSuffix, POSTINGS_EXTENSION);
+  }
+
+  @Override
+  public FieldsConsumer fieldsConsumer(SegmentWriteState state) throws IOException {
+    TermsIndexWriterBase indexWriter = new FixedGapTermsIndexWriter(state);
+    BitSetPostingsWriter postingsWriter = new BitSetPostingsWriter(state);
+    return new BlockTermsWriter(indexWriter, state, postingsWriter);
+  }
+
+  @Override
+  public FieldsProducer fieldsProducer(SegmentReadState state) throws IOException {
+    PostingsReaderBase postings = new BitSetPostingsReader(state);
+    TermsIndexReaderBase indexReader = new FixedGapTermsIndexReader(state.directory,
+        state.fieldInfos,
+        state.segmentInfo.name,
+        BytesRef.getUTF8SortedAsUnicodeComparator(),
+        state.segmentSuffix,
+        state.context);
+    return new BlockTermsReader(indexReader,
+        state.directory,
+        state.fieldInfos,
+        state.segmentInfo,
+        postings,
+        state.context,
+        state.segmentSuffix);
+  }
+}
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsReader.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsReader.java
new file mode 100644
index 0000000..0431765
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsReader.java
@@ -0,0 +1,79 @@
+package org.apache.lucene.codecs.bits;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.lucene.codecs.BlockTermState;
+import org.apache.lucene.codecs.PostingsReaderBase;
+import org.apache.lucene.index.DocsAndPositionsEnum;
+import org.apache.lucene.index.DocsEnum;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.SegmentReadState;
+import org.apache.lucene.store.DataInput;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.util.Bits;
+
+import java.io.IOException;
+
+class BitSetPostingsReader extends PostingsReaderBase {
+
+  private IndexInput pst;
+  private SegmentReadState segmentReadState;
+
+  BitSetPostingsReader(SegmentReadState state) throws IOException {
+    this.segmentReadState = state;
+    pst = state.directory.openInput(
+        BitSetPostingsFormat.getPostingsFileName(state.segmentInfo.name, state.segmentSuffix),
+        state.context);
+  }
+
+  @Override
+  public void init(IndexInput termsIn) throws IOException {
+  }
+
+  @Override
+  public BlockTermState newTermState() throws IOException {
+    return new BitSetBlockTermState();
+  }
+
+  @Override
+  public void decodeTerm(long[] longs, DataInput in, FieldInfo fieldInfo, BlockTermState state, boolean absolute) throws IOException {
+    assert longs.length == BitSetPostingsWriter.METADATA_LONG_SIZE;
+    ((BitSetBlockTermState) state).startPostingsPosition = in.readVLong();
+  }
+
+  @Override
+  public DocsEnum docs(FieldInfo fieldInfo, BlockTermState state, Bits skipDocs, DocsEnum reuse, int flags) throws IOException {
+    BitSetBlockTermState postingTermsState = (BitSetBlockTermState) state;
+    return new BitSetDocsEnum(postingTermsState.startPostingsPosition, skipDocs, pst, segmentReadState.segmentInfo.getDocCount());
+  }
+
+  @Override
+  public DocsAndPositionsEnum docsAndPositions(FieldInfo fieldInfo, BlockTermState state, Bits skipDocs, DocsAndPositionsEnum reuse, int flags) throws IOException {
+    return null;
+  }
+
+  @Override
+  public long ramBytesUsed() {
+    return 0;
+  }
+
+  @Override
+  public void close() throws IOException {
+    pst.close();
+  }
+}
diff --git a/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsWriter.java b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsWriter.java
new file mode 100644
index 0000000..eb6fbfd
--- /dev/null
+++ b/lucene/codecs/src/java/org/apache/lucene/codecs/bits/BitSetPostingsWriter.java
@@ -0,0 +1,83 @@
+package org.apache.lucene.codecs.bits;
+
+import org.apache.lucene.codecs.BlockTermState;
+import org.apache.lucene.codecs.PushPostingsWriterBase;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.SegmentWriteState;
+import org.apache.lucene.store.DataOutput;
+import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.util.BytesRef;
+
+import java.io.IOException;
+
+class BitSetPostingsWriter extends PushPostingsWriterBase {
+  static final int METADATA_LONG_SIZE = 0;
+  private final IndexOutput pst;
+  private final SegmentWriteState state;
+  private BitSetPostingsFileWriter postingsWriter;
+  private long startPostingPosition;
+
+  BitSetPostingsWriter(SegmentWriteState state) throws IOException {
+    String fileName = BitSetPostingsFormat.getPostingsFileName(state.segmentInfo.name, state.segmentSuffix);
+    pst = state.directory.createOutput(fileName, state.context);
+    this.state = state;
+  }
+
+  @Override
+  public void startTerm() throws IOException {
+    startPostingPosition = pst.getFilePointer();
+    postingsWriter.startPostingsList();
+  }
+
+  @Override
+  public void finishTerm(BlockTermState state) throws IOException {
+    postingsWriter.finishPostingsList();
+    if (pst.getFilePointer() - startPostingPosition > 0) {
+      ((BitSetBlockTermState) state).startPostingsPosition = startPostingPosition;
+    }
+  }
+
+  @Override
+  public BlockTermState newTermState() throws IOException {
+    return new BitSetBlockTermState();
+  }
+
+  @Override
+  public void encodeTerm(long[] longs, DataOutput out, FieldInfo fieldInfo, BlockTermState state, boolean absolute) throws IOException {
+    if ( FieldInfo.IndexOptions.DOCS_ONLY != fieldInfo.getIndexOptions()) {
+      throw new IllegalArgumentException("Incorrect index option: " + fieldInfo.getIndexOptions() + ". " +
+          "Only " + FieldInfo.IndexOptions.DOCS_ONLY + " is accepted.");
+    }
+    assert longs.length == METADATA_LONG_SIZE;
+    out.writeVLong(((BitSetBlockTermState) state).startPostingsPosition);
+  }
+
+  @Override
+  public int setField(FieldInfo fieldInfo) {
+    super.setField(fieldInfo);
+    postingsWriter = new BitSetPostingsFileWriter(state.segmentInfo.getDocCount(), pst);
+    return METADATA_LONG_SIZE;
+  }
+
+  @Override
+  public void close() throws IOException {
+    pst.close();
+  }
+
+  @Override
+  public void startDoc(int docID, int freq) throws IOException {
+    postingsWriter.startDoc(docID);
+  }
+
+  @Override
+  public void addPosition(int position, BytesRef payload, int startOffset, int endOffset) throws IOException {
+  }
+
+  @Override
+  public void finishDoc() throws IOException {
+  }
+
+  @Override
+  public void init(IndexOutput termsOut) throws IOException {
+  }
+}
diff --git a/lucene/codecs/src/resources/META-INF/services/org.apache.lucene.codecs.Codec b/lucene/codecs/src/resources/META-INF/services/org.apache.lucene.codecs.Codec
index fcd5ded..8cb557a 100644
--- a/lucene/codecs/src/resources/META-INF/services/org.apache.lucene.codecs.Codec
+++ b/lucene/codecs/src/resources/META-INF/services/org.apache.lucene.codecs.Codec
@@ -14,3 +14,4 @@
 #  limitations under the License.
 
 org.apache.lucene.codecs.simpletext.SimpleTextCodec
+org.apache.lucene.codecs.bits.BitSetCodec
\ No newline at end of file
diff --git a/lucene/codecs/src/test/org/apache/lucene/codecs/bits/BitSetCodecTest.java b/lucene/codecs/src/test/org/apache/lucene/codecs/bits/BitSetCodecTest.java
new file mode 100644
index 0000000..6bcd905
--- /dev/null
+++ b/lucene/codecs/src/test/org/apache/lucene/codecs/bits/BitSetCodecTest.java
@@ -0,0 +1,74 @@
+package org.apache.lucene.codecs.bits;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.index.BasePostingsFormatTestCase;
+import org.junit.Ignore;
+
+public class BitSetCodecTest extends BasePostingsFormatTestCase {
+
+    private Codec codec = new BitSetCodec();
+
+    @Override
+    protected Codec getCodec() {
+        return codec;
+    }
+
+    @Override
+    @Ignore
+    public void testDocsAndFreqs() throws Exception {
+        super.testDocsAndFreqs(); // not supported
+    }
+
+    @Override
+    @Ignore
+    public void testDocsAndFreqsAndPositions() throws Exception {
+        super.testDocsAndFreqsAndPositions(); // not supported
+    }
+
+    @Override
+    @Ignore
+    public void testDocsAndFreqsAndPositionsAndPayloads() throws Exception {
+        super.testDocsAndFreqsAndPositionsAndPayloads();  // not supported
+    }
+
+    @Override
+    @Ignore
+    public void testDocsAndFreqsAndPositionsAndOffsets() throws Exception {
+        super.testDocsAndFreqsAndPositionsAndOffsets();  // not supported
+    }
+
+    @Override
+    @Ignore
+    public void testDocsAndFreqsAndPositionsAndOffsetsAndPayloads() throws Exception {
+        super.testDocsAndFreqsAndPositionsAndOffsetsAndPayloads();  // not supported
+    }
+
+    @Override
+    @Ignore
+    public void testRandom() throws Exception {
+        super.testRandom();  // not supported
+    }
+
+    @Override
+    @Ignore
+    public void testInvertedWrite() throws Exception {
+        super.testInvertedWrite();   // not supported
+    }
+}