/**
* 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.drill.exec.vector.complex;
import com.google.common.base.Preconditions;
import org.apache.drill.exec.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 UInt4Vector.Accessor accessor = offsets.getAccessor();
final UInt4Vector.Mutator mutator = offsets.getMutator();
final int lastSet = Math.max(accessor.getValueCount() - 1, 0);
final int previousEnd = accessor.get(lastSet);//0 ? 0 : accessor.get(lastSet);
for (int i = lastSet; i < lastIndex; i++) {
mutator.setSafe(i + 1, previousEnd);
}
mutator.setValueCount(lastIndex+1);
}
}