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.runtime.aggregates.serializable.std;
  
  import java.io.DataOutput;
  import java.io.IOException;
  
  import org.apache.asterix.formats.nontagged.SerializerDeserializerProvider;
  import org.apache.asterix.om.base.AInt64;
  import org.apache.asterix.om.base.AMutableInt64;
  import org.apache.asterix.om.base.ANull;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.EnumDeserializer;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.dataflow.value.ISerializerDeserializer;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.exceptions.SourceLocation;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  /**
   * count(NULL) returns NULL.
   */
  public abstract class AbstractSerializableCountAggregateFunction extends AbstractSerializableAggregateFunction {
      private static final int MET_NULL_OFFSET = 0;
      private static final int COUNT_OFFSET = 1;
  
      private AMutableInt64 result = new AMutableInt64(-1);
      @SuppressWarnings("unchecked")
      private ISerializerDeserializer<AInt64> int64Serde =
              SerializerDeserializerProvider.INSTANCE.getSerializerDeserializer(BuiltinType.AINT64);
      @SuppressWarnings("unchecked")
      private ISerializerDeserializer<ANull> nullSerde =
              SerializerDeserializerProvider.INSTANCE.getSerializerDeserializer(BuiltinType.ANULL);
      private IPointable inputVal = new VoidPointable();
      private IScalarEvaluator eval;
  
      public AbstractSerializableCountAggregateFunction(IScalarEvaluatorFactory[] args, IEvaluatorContext context,
              SourceLocation sourceLoc) throws HyracksDataException {
          super(sourceLoc);
          eval = args[0].createScalarEvaluator(context);
      }
  
      @Override
      public void init(DataOutput state) throws HyracksDataException {
          try {
              state.writeBoolean(false);
              state.writeLong(0);
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
      }
  
      @Override
      public void step(IFrameTupleReference tuple, byte[] state, int start, int len) throws HyracksDataException {
          boolean metNull = BufferSerDeUtil.getBoolean(state, start);
          long cnt = BufferSerDeUtil.getLong(state, start + 1);
          eval.evaluate(tuple, inputVal);
          ATypeTag typeTag =
                  EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(inputVal.getByteArray()[inputVal.getStartOffset()]);
          if (typeTag == ATypeTag.MISSING || typeTag == ATypeTag.NULL) {
              processNull(state, start);
          } else {
              cnt = processValue(typeTag, cnt);
          }
          BufferSerDeUtil.writeBoolean(metNull, state, start + MET_NULL_OFFSET);
          BufferSerDeUtil.writeLong(cnt, state, start + COUNT_OFFSET);
      }
  
      @Override
      public void finish(byte[] state, int start, int len, DataOutput out) throws HyracksDataException {
          boolean metNull = BufferSerDeUtil.getBoolean(state, start);
          long cnt = BufferSerDeUtil.getLong(state, start + 1);
          try {
              if (metNull) {
                  nullSerde.serialize(ANull.NULL, out);
              } else {
                  result.setValue(cnt);
                  int64Serde.serialize(result, out);
              }
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
      }
  
      @Override
      public void finishPartial(byte[] state, int start, int len, DataOutput out) throws HyracksDataException {
          finish(state, start, len, out);
      }
  
      protected void processNull(byte[] state, int start) {
          BufferSerDeUtil.writeBoolean(true, state, start + MET_NULL_OFFSET);
      }
  
      protected long processValue(ATypeTag tag, long cnt) {
          return cnt + 1;
      }
  }
  