package org.galagosearch.core.index;

 import java.io.IOException;

 import java.io.OutputStream;

 public class ExtentListBuffer implements IndexElement {

     public ExtentListBuffer() {

         super();

         documentCount = 0;

         extentCount = 0;

         endCount = 0;

         data = new CompressedByteBuffer();

         header = new CompressedByteBuffer();

         documentExtents = new CompressedByteBuffer();

     }

     public long dataLength() {

         long listLength = 0;

         listLength += header.length();

         listLength += data.length();

         return listLength;

     }

     public void write(final OutputStream output) throws IOException {

         output.write(header.getBytes(), 0, header.length());

         output.write(data.getBytes(), 0, data.length());

     }

     public byte[] key() {

         return word;

     }

     public void setWord(byte[] word) {

         this.word = word;

         this.lastDocument = 0;

         this.lastPosition = 0;

         this.extentCount = 0;

     }

     void setValue(long value) {

         this.value = value;

     }

     private void storePreviousDocument() {

         if (data.position > 0) {

             data.add(extentCount);

             data.add(documentExtents);

             documentExtents.clear();

         }

     }

     public void addDocument(long documentID) {

         storePreviousDocument();

         data.add(documentID - lastDocument);

         lastDocument = documentID;

         lastStartExtent = 0;

         extentCount = 0;

         endCount = 0;

         value = 0;

         documentCount++;

     }

     public void addBegin(int begin) {

         extentCount++;

         documentExtents.add(begin - lastStartExtent);

         lastStartExtent = begin;

     }

     public void addEnd(int end) {

         endCount++;

         // Record multiple extents at the same begin location

         if (endCount > extentCount) {

             documentExtents.add(0);

             extentCount++;

         }

         documentExtents.add(end - lastStartExtent);

         documentExtents.add(value);

     }

     public void close() {

         int options = 0;

         storePreviousDocument();

         header.add(options);

         header.add(documentCount);

     }

     private long value;

     private long lastDocument;

     private int lastStartExtent;

     private int lastPosition;

     private int extentCount;

     private int endCount;

     private int documentCount;

     public byte[] word;

     public CompressedByteBuffer header;

     public CompressedByteBuffer data;

     public CompressedByteBuffer documentExtents;

 }