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.asterix.fuzzyjoin.recordgroup;
  
  import java.io.DataInputStream;
  import java.io.EOFException;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.util.ArrayList;
  
  import org.apache.asterix.fuzzyjoin.similarity.SimilarityFilters;
  
  public class RecordGroupLengthCount extends RecordGroup {
      private final int min;
      private final int max;
      private final int[] lengthGroups;
  
      public RecordGroupLengthCount(int noGroups, SimilarityFilters fuzzyFilters, String lengthstatsPath) {
          super(noGroups, fuzzyFilters);
  
          int sum = 0;
          int range = 0;
  
          try (DataInputStream in = new DataInputStream(new FileInputStream(lengthstatsPath))) {
              min = in.readInt();
              max = in.readInt();
              range = max - min + 1;
              lengthGroups = new int[range]; // stores freqencies initally
              try {
                  while (true) {
                      int length = in.readInt();
                      int freq = in.readInt();
  
                      int lowAbs = fuzzyFilters.getLengthLowerBound(length);
                      int uppAbs = fuzzyFilters.getLengthUpperBound(length);
  
                      int low = Math.max(lowAbs - min, 0);
                      int upp = Math.min(uppAbs - min, max - min);
  
                      for (int l = low; l <= upp; ++l) {
                          lengthGroups[l] += freq;
                          sum += freq;
                      }
                  }
              } catch (EOFException e) {
              }
          } catch (IOException ioe) {
              throw new RuntimeException(ioe);
          }
  
          int countGroup = sum / noGroups;
          int count = 0;
          int group = 0;
          for (int i = 0; i < range; ++i) {
              count += lengthGroups[i];
              lengthGroups[i] = group;
              if (count >= countGroup && group < noGroups - 1) {
                  count = 0;
                  group++;
              }
          }
      }
  
      @Override
      public Iterable<Integer> getGroups(Integer token, Integer length) {
          int lowAbs = fuzzyFilters.getLengthLowerBound(length);
          int uppAbs = fuzzyFilters.getLengthUpperBound(length);
  
          int low = Math.max(lowAbs - min, 0);
          int upp = Math.min(uppAbs - min, max - min);
  
          ArrayList<Integer> groups = new ArrayList<Integer>(upp - low + 1);
          int prevGroup = -1;
          for (int l = low; l <= upp; ++l) {
              int group = lengthGroups[l];
              if (group != prevGroup) {
                  groups.add(group);
                  prevGroup = group;
              }
          }
  
          // System.out.println(noGroups + ":" + length + " [" + low + "," + upp
          // + "] " + groups);
  
          return groups;
      }
  
      @Override
      public boolean isLengthOnly() {
          return true;
      }
  
  }
  