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.impl;
  
  import org.apache.arrow.vector.ValueVector;
  import org.apache.arrow.vector.complex.FixedSizeListVector;
  import org.apache.arrow.vector.complex.reader.FieldReader;
  import org.apache.arrow.vector.complex.writer.BaseWriter.ListWriter;
  import org.apache.arrow.vector.complex.writer.FieldWriter;
  import org.apache.arrow.vector.holders.UnionHolder;
  import org.apache.arrow.vector.types.Types.MinorType;
  
  /** Reader for fixed size list vectors. */
  public class UnionFixedSizeListReader extends AbstractFieldReader {
  
    private final FixedSizeListVector vector;
    private final ValueVector data;
    private final int listSize;
  
    private int currentOffset;
  
    /** Constructs a new instance that reads data in <code>vector</code>. */
    public UnionFixedSizeListReader(FixedSizeListVector vector) {
      this.vector = vector;
      this.data = vector.getDataVector();
      this.listSize = vector.getListSize();
    }
  
    @Override
    public boolean isSet() {
      return !vector.isNull(idx());
    }
  
    @Override
    public FieldReader reader() {
      return data.getReader();
    }
  
    @Override
    public Object readObject() {
      return vector.getObject(idx());
    }
  
    @Override
    public MinorType getMinorType() {
      return vector.getMinorType();
    }
  
    @Override
    public void setPosition(int index) {
      super.setPosition(index);
      data.getReader().setPosition(index * listSize);
      currentOffset = 0;
    }
  
    @Override
    public void read(int index, UnionHolder holder) {
      setPosition(idx());
      for (int i = -1; i < index; i++) {
        if (!next()) {
          throw new IndexOutOfBoundsException("Requested " + index + ", size " + listSize);
        }
      }
      holder.reader = data.getReader();
      holder.isSet = vector.isNull(idx()) ? 0 : 1;
    }
  
    @Override
    public int size() {
      return listSize;
    }
  
    @Override
    public boolean next() {
      if (currentOffset < listSize) {
        data.getReader().setPosition(idx() * listSize + currentOffset++);
        return true;
      } else {
        return false;
      }
    }
  
    @Override
    public void copyAsValue(ListWriter writer) {
      ComplexCopier.copy(this, (FieldWriter) writer);
    }
  }
  