package org.apache.lucene.index;/** * 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 java.io.IOException;import java.util.Arrays;import org.apache.lucene.store.IndexInput;/** * Implements the skip list reader for the default posting list format * that stores positions and payloads. * */class DefaultSkipListReader extends MultiLevelSkipListReader {  private boolean currentFieldStoresPayloads;  private long freqPointer[];  private long proxPointer[];  private int payloadLength[];    private long lastFreqPointer;  private long lastProxPointer;  private int lastPayloadLength;                             DefaultSkipListReader(IndexInput skipStream, int maxSkipLevels, int skipInterval) {    super(skipStream, maxSkipLevels, skipInterval);    freqPointer = new long[maxSkipLevels];    proxPointer = new long[maxSkipLevels];    payloadLength = new int[maxSkipLevels];  }    void init(long skipPointer, long freqBasePointer, long proxBasePointer, int df, boolean storesPayloads) {    super.init(skipPointer, df);    this.currentFieldStoresPayloads = storesPayloads;    lastFreqPointer = freqBasePointer;    lastProxPointer = proxBasePointer;    Arrays.fill(freqPointer, freqBasePointer);    Arrays.fill(proxPointer, proxBasePointer);    Arrays.fill(payloadLength, 0);  }  /** Returns the freq pointer of the doc to which the last call of    * {@link MultiLevelSkipListReader#skipTo(int)} has skipped.  */  long getFreqPointer() {    return lastFreqPointer;  }  /** Returns the prox pointer of the doc to which the last call of    * {@link MultiLevelSkipListReader#skipTo(int)} has skipped.  */  long getProxPointer() {    return lastProxPointer;  }    /** Returns the payload length of the payload stored just before    * the doc to which the last call of {@link MultiLevelSkipListReader#skipTo(int)}    * has skipped.  */  int getPayloadLength() {    return lastPayloadLength;  }    protected void seekChild(int level) throws IOException {    super.seekChild(level);    freqPointer[level] = lastFreqPointer;    proxPointer[level] = lastProxPointer;    payloadLength[level] = lastPayloadLength;  }    protected void setLastSkipData(int level) {    super.setLastSkipData(level);    lastFreqPointer = freqPointer[level];    lastProxPointer = proxPointer[level];    lastPayloadLength = payloadLength[level];  }  protected int readSkipData(int level, IndexInput skipStream) throws IOException {    int delta;    if (currentFieldStoresPayloads) {      // the current field stores payloads.      // if the doc delta is odd then we have      // to read the current payload length      // because it differs from the length of the      // previous payload      delta = skipStream.readVInt();      if ((delta & 1) != 0) {        payloadLength[level] = skipStream.readVInt();      }      delta >>>= 1;    } else {      delta = skipStream.readVInt();    }    freqPointer[level] += skipStream.readVInt();    proxPointer[level] += skipStream.readVInt();        return delta;  }}