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.cassandra.index.sai.disk.v1.bbtree;
  
  import java.io.IOException;
  
  import com.carrotsearch.hppc.IntLongHashMap;
  import com.carrotsearch.hppc.IntLongMap;
  import org.apache.cassandra.index.sai.disk.io.IndexInputReader;
  import org.apache.cassandra.io.util.FileHandle;
  import org.apache.cassandra.io.util.RandomAccessReader;
  
  import static org.apache.cassandra.index.sai.disk.v1.SAICodecUtils.validate;
  
  /**
   * Mapping between node ID and an offset to its auxiliary posting list (containing every row id from all leaves
   * reachable from that node. See {@link BlockBalancedTreePostingsWriter}).
   */
  class BlockBalancedTreePostingsIndex
  {
      private final int size;
      public final IntLongMap index = new IntLongHashMap();
  
      BlockBalancedTreePostingsIndex(FileHandle postingsFileHandle, long filePosition) throws IOException
      {
          try (RandomAccessReader reader = postingsFileHandle.createReader();
               IndexInputReader input = IndexInputReader.create(reader))
          {
              validate(input);
              input.seek(filePosition);
  
              size = input.readVInt();
  
              for (int x = 0; x < size; x++)
              {
                  final int node = input.readVInt();
                  final long filePointer = input.readVLong();
  
                  index.put(node, filePointer);
              }
          }
      }
  
      /**
       * Returns <tt>true</tt> if given node ID has an auxiliary posting list.
       */
      boolean exists(int nodeID)
      {
          return index.containsKey(nodeID);
      }
  
      /**
       * Returns an offset within the balanced tree postings file to the begining of the blocks summary of given node's auxiliary
       * posting list.
       *
       * @throws IllegalArgumentException when given nodeID doesn't have an auxiliary posting list. Check first with
       * {@link #exists(int)}
       */
      long getPostingsFilePointer(int nodeID)
      {
          return index.get(nodeID);
      }
  
      int size()
      {
          return size;
      }
  }
  