content: /*
   * 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.
   */
  
  package org.apache.carbondata.core.datastore.columnar;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.carbondata.core.constants.CarbonCommonConstants;
  import org.apache.carbondata.core.util.ByteUtil;
  
  public abstract class BlockIndexerStorage<T> {
  
    protected short[] rowIdPage;
  
    protected short[] rowIdRlePage;
  
    protected T dataPage;
  
    protected short[] dataRlePage;
  
    public short[] getRowIdPage() {
      return rowIdPage;
    }
  
    public int getRowIdPageLengthInBytes() {
      if (rowIdPage != null) {
        return rowIdPage.length * CarbonCommonConstants.SHORT_SIZE_IN_BYTE;
      } else {
        return 0;
      }
    }
  
    public short[] getRowIdRlePage() {
      return rowIdRlePage;
    }
  
    public int getRowIdRlePageLengthInBytes() {
      if (rowIdRlePage != null) {
        return rowIdRlePage.length * CarbonCommonConstants.SHORT_SIZE_IN_BYTE;
      } else {
        return 0;
      }
    }
  
    public T getDataPage() {
      return dataPage;
    }
  
    public short[] getDataRlePage() {
      return dataRlePage;
    }
  
    public int getDataRlePageLengthInBytes() {
      if (dataRlePage != null) {
        return dataRlePage.length * CarbonCommonConstants.SHORT_SIZE_IN_BYTE;
      } else {
        return 0;
      }
    }
  
    /**
     * It compresses depends up on the sequence numbers.
     * [1,2,3,4,6,8,10,11,12,13] is translated to [1,4,6,8,10,13] and [0,6]. In
     * first array the start and end of sequential numbers and second array
     * keeps the indexes of where sequential numbers starts. If there is no
     * sequential numbers then the same array it returns with empty second
     * array.
     *
     * @param rowIds
     */
    protected void encodeAndSetRowId(short[] rowIds) {
      List<Short> list = new ArrayList<Short>(CarbonCommonConstants.CONSTANT_SIZE_TEN);
      List<Short> map = new ArrayList<Short>(CarbonCommonConstants.CONSTANT_SIZE_TEN);
      int k = 0;
      int i = 1;
      for (; i < rowIds.length; i++) {
        if (rowIds[i] - rowIds[i - 1] == 1) {
          k++;
        } else {
          if (k > 0) {
            map.add(((short) list.size()));
            list.add(rowIds[i - k - 1]);
            list.add(rowIds[i - 1]);
          } else {
            list.add(rowIds[i - 1]);
          }
          k = 0;
        }
      }
      if (k > 0) {
        map.add(((short) list.size()));
        list.add(rowIds[i - k - 1]);
        list.add(rowIds[i - 1]);
      } else {
        list.add(rowIds[i - 1]);
      }
      if ((((list.size() + map.size()) * 100) / rowIds.length) > 70) {
        this.rowIdPage = rowIds;
        this.rowIdRlePage = new short[0];
      } else {
        this.rowIdPage = convertToArray(list);
        this.rowIdRlePage = convertToArray(map);
      }
    }
  
    /**
     * apply RLE(run-length encoding) on byte array data page
     */
    protected byte[][] rleEncodeOnData(byte[][] dataPage) {
      List<Short> map = new ArrayList<>(CarbonCommonConstants.CONSTANT_SIZE_TEN);
      List<byte[]> list = new ArrayList<>(dataPage.length / 2);
      list.add(dataPage[0]);
      short counter = 1;
      short startIdx = 0;
      for (int i = 1; i < dataPage.length; i++) {
        if (ByteUtil.UnsafeComparer.INSTANCE.compareTo(dataPage[i - 1], dataPage[i]) != 0) {
          list.add(dataPage[i]);
          map.add(startIdx);
          map.add(counter);
          startIdx += counter;
          counter = 1;
          continue;
        }
        counter++;
      }
      map.add(startIdx);
      map.add(counter);
      // if rle is index size is more than 70% then rle wont give any benefit
      // so better to avoid rle index and write data as it is
      if ((((list.size() + map.size()) * 100) / dataPage.length) > 70) {
        this.dataRlePage = new short[0];
        return dataPage;
      } else {
        this.dataRlePage = convertToArray(map);
        return convertToDataPage(list);
      }
    }
  
    private short[] convertToArray(List<Short> list) {
      short[] shortArray = new short[list.size()];
      for (int i = 0; i < shortArray.length; i++) {
        shortArray[i] = list.get(i);
      }
      return shortArray;
    }
  
    private byte[][] convertToDataPage(List<byte[]> list) {
      byte[][] shortArray = new byte[list.size()][];
      for (int i = 0; i < shortArray.length; i++) {
        shortArray[i] = list.get(i);
      }
      return shortArray;
    }
  }
  