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.arrow.vector.complex;
  
  import org.apache.arrow.util.Preconditions;
  import org.apache.arrow.vector.UInt4Vector;
  
  /** A helper class that is used to track and populate empty values in repeated value vectors. */
  public class EmptyValuePopulator {
    private final UInt4Vector offsets;
  
    public EmptyValuePopulator(UInt4Vector offsets) {
      this.offsets = Preconditions.checkNotNull(offsets, "offsets cannot be null");
    }
  
    /**
     * Marks all values since the last set as empty. The last set value is obtained from underlying
     * offsets vector.
     *
     * @param lastIndex the last index (inclusive) in the offsets vector until which empty population
     *     takes place
     * @throws java.lang.IndexOutOfBoundsException if lastIndex is negative or greater than offsets
     *     capacity.
     */
    public void populate(int lastIndex) {
      if (lastIndex < 0) {
        throw new IndexOutOfBoundsException("index cannot be negative");
      }
      final int lastSet = Math.max(offsets.getValueCount() - 1, 0);
      final int previousEnd = offsets.get(lastSet); // 0 ? 0 : accessor.get(lastSet);
      for (int i = lastSet; i < lastIndex; i++) {
        offsets.setSafe(i + 1, previousEnd);
      }
      offsets.setValueCount(lastIndex + 1);
    }
  }
  