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.unnestingfunctions.std;
  
  import java.io.IOException;
  
  import org.apache.asterix.common.exceptions.ErrorCode;
  import org.apache.asterix.common.exceptions.RuntimeDataException;
  import org.apache.asterix.dataflow.data.nontagged.serde.AOrderedListSerializerDeserializer;
  import org.apache.asterix.dataflow.data.nontagged.serde.AUnorderedListSerializerDeserializer;
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.EnumDeserializer;
  import org.apache.asterix.om.types.hierachy.ATypeHierarchy;
  import org.apache.asterix.om.utils.NonTaggedFormatUtil;
  import org.apache.asterix.runtime.unnestingfunctions.base.AbstractUnnestingFunctionDynamicDescriptor;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.algebricks.runtime.base.IUnnestingEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IUnnestingEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  public class SubsetCollectionDescriptor extends AbstractUnnestingFunctionDynamicDescriptor {
      private static final long serialVersionUID = 1L;
      public static final IFunctionDescriptorFactory FACTORY = SubsetCollectionDescriptor::new;
  
      @Override
      public IUnnestingEvaluatorFactory createUnnestingEvaluatorFactory(final IScalarEvaluatorFactory[] args) {
          return new IUnnestingEvaluatorFactory() {
              private static final long serialVersionUID = 1L;
  
              @Override
              public IUnnestingEvaluator createUnnestingEvaluator(IEvaluatorContext ctx) throws HyracksDataException {
                  return new IUnnestingEvaluator() {
                      private IPointable inputVal = new VoidPointable();
                      private IScalarEvaluator evalList = args[0].createScalarEvaluator(ctx);
                      private IScalarEvaluator evalStart = args[1].createScalarEvaluator(ctx);
                      private IScalarEvaluator evalLen = args[2].createScalarEvaluator(ctx);
                      private ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
                      private int numItems;
                      private int numItemsMax;
                      private int posStart;
                      private int posCrt;
                      private ATypeTag itemTag;
                      private boolean selfDescList = false;
                      private boolean metUnknown = false;
  
                      @Override
                      public void init(IFrameTupleReference tuple) throws HyracksDataException {
                          try {
                              evalStart.evaluate(tuple, inputVal);
                              posStart = ATypeHierarchy.getIntegerValue(getIdentifier().getName(), 0,
                                      inputVal.getByteArray(), inputVal.getStartOffset());
  
                              evalLen.evaluate(tuple, inputVal);
                              numItems = ATypeHierarchy.getIntegerValue(getIdentifier().getName(), 1,
                                      inputVal.getByteArray(), inputVal.getStartOffset());
  
                              evalList.evaluate(tuple, inputVal);
                              byte[] serList = inputVal.getByteArray();
                              int offset = inputVal.getStartOffset();
                              metUnknown = false;
  
                              byte typeTag = serList[offset];
                              if (typeTag == ATypeTag.SERIALIZED_MISSING_TYPE_TAG
                                      || typeTag == ATypeTag.SERIALIZED_NULL_TYPE_TAG) {
                                  metUnknown = true;
                                  return;
                              }
  
                              if (typeTag != ATypeTag.SERIALIZED_ORDEREDLIST_TYPE_TAG
                                      && typeTag != ATypeTag.SERIALIZED_UNORDEREDLIST_TYPE_TAG) {
                                  throw new RuntimeDataException(ErrorCode.COERCION, getIdentifier().getName());
                              }
                              if (typeTag == ATypeTag.SERIALIZED_ORDEREDLIST_TYPE_TAG) {
                                  numItemsMax = AOrderedListSerializerDeserializer.getNumberOfItems(serList, offset);
                              } else {
                                  numItemsMax = AUnorderedListSerializerDeserializer.getNumberOfItems(serList, offset);
                              }
  
                              itemTag = EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(serList[offset + 1]);
                              if (itemTag == ATypeTag.ANY) {
                                  selfDescList = true;
                              }
  
                              posCrt = posStart;
                          } catch (IOException e) {
                              throw HyracksDataException.create(e);
                          }
                      }
  
                      @Override
                      public boolean step(IPointable result) throws HyracksDataException {
                          if (!metUnknown && posCrt < posStart + numItems && posCrt < numItemsMax) {
                              resultStorage.reset();
                              byte[] serList = inputVal.getByteArray();
                              int offset = inputVal.getStartOffset();
                              int itemLength = 0;
                              try {
                                  int itemOffset =
                                          AOrderedListSerializerDeserializer.getItemOffset(serList, offset, posCrt);
                                  if (selfDescList) {
                                      itemTag = EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(serList[itemOffset]);
                                  }
                                  itemLength = NonTaggedFormatUtil.getFieldValueLength(serList, itemOffset, itemTag,
                                          selfDescList);
                                  if (!selfDescList) {
                                      resultStorage.getDataOutput().writeByte(itemTag.serialize());
                                  }
                                  resultStorage.getDataOutput().write(serList, itemOffset,
                                          itemLength + (!selfDescList ? 0 : 1));
                              } catch (IOException e) {
                                  throw HyracksDataException.create(e);
                              }
                              result.set(resultStorage);
                              ++posCrt;
                              return true;
                          }
                          return false;
                      }
                  };
              }
          };
      }
  
      @Override
      public FunctionIdentifier getIdentifier() {
          return BuiltinFunctions.SUBSET_COLLECTION;
      }
  
  }
  