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.evaluators.common;
  
  import java.io.DataOutput;
  import java.io.IOException;
  
  import org.apache.asterix.formats.nontagged.SerializerDeserializerProvider;
  import org.apache.asterix.fuzzyjoin.similarity.SimilarityMetricEditDistance;
  import org.apache.asterix.om.base.AInt64;
  import org.apache.asterix.om.base.AMutableInt64;
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.EnumDeserializer;
  import org.apache.asterix.runtime.evaluators.functions.PointableHelper;
  import org.apache.asterix.runtime.exceptions.IncompatibleTypeException;
  import org.apache.asterix.runtime.exceptions.TypeMismatchException;
  import org.apache.asterix.runtime.exceptions.UnsupportedItemTypeException;
  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.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  public class EditDistanceEvaluator implements IScalarEvaluator {
  
      // assuming type indicator in serde format
      protected final int typeIndicatorSize = 1;
  
      protected final ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
      protected final DataOutput out = resultStorage.getDataOutput();
      protected final IPointable argPtr1 = new VoidPointable();
      protected final IPointable argPtr2 = new VoidPointable();
      protected final IScalarEvaluator firstStringEval;
      protected final IScalarEvaluator secondStringEval;
      protected final SourceLocation sourceLoc;
      protected final SimilarityMetricEditDistance ed = new SimilarityMetricEditDistance();
      protected final OrderedListIterator firstOrdListIter = new OrderedListIterator();
      protected final OrderedListIterator secondOrdListIter = new OrderedListIterator();
      protected int editDistance = 0;
      protected final AMutableInt64 aInt64 = new AMutableInt64(-1);
      @SuppressWarnings("unchecked")
      protected final ISerializerDeserializer<AInt64> int64Serde =
              SerializerDeserializerProvider.INSTANCE.getSerializerDeserializer(BuiltinType.AINT64);
      protected ATypeTag itemTypeTag;
  
      protected ATypeTag firstTypeTag;
      protected ATypeTag secondTypeTag;
  
      public EditDistanceEvaluator(IScalarEvaluatorFactory[] args, IEvaluatorContext context, SourceLocation sourceLoc)
              throws HyracksDataException {
          firstStringEval = args[0].createScalarEvaluator(context);
          secondStringEval = args[1].createScalarEvaluator(context);
          this.sourceLoc = sourceLoc;
      }
  
      @Override
      public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
          resultStorage.reset();
          firstStringEval.evaluate(tuple, argPtr1);
          secondStringEval.evaluate(tuple, argPtr2);
  
          if (PointableHelper.checkAndSetMissingOrNull(result, argPtr1, argPtr2)) {
              return;
          }
  
          firstTypeTag =
                  EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(argPtr1.getByteArray()[argPtr1.getStartOffset()]);
          secondTypeTag =
                  EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(argPtr2.getByteArray()[argPtr2.getStartOffset()]);
  
          if (!checkArgTypes(firstTypeTag, secondTypeTag)) {
              result.set(resultStorage);
              return;
          }
  
          editDistance = computeResult(argPtr1, argPtr2, firstTypeTag);
          try {
              writeResult(editDistance);
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
          result.set(resultStorage);
      }
  
      protected int computeResult(IPointable left, IPointable right, ATypeTag argType) throws HyracksDataException {
          byte[] leftBytes = left.getByteArray();
          int leftStartOffset = left.getStartOffset();
          byte[] rightBytes = right.getByteArray();
          int rightStartOffset = right.getStartOffset();
  
          switch (argType) {
              case STRING: {
                  // Passes -1 as the simThresh to calculate the edit distance
                  // without applying any calculation optimizations.
                  return ed.getActualUTF8StringEditDistanceVal(leftBytes, leftStartOffset + typeIndicatorSize, rightBytes,
                          rightStartOffset + typeIndicatorSize, -1);
              }
              case ARRAY: {
                  firstOrdListIter.reset(leftBytes, leftStartOffset);
                  secondOrdListIter.reset(rightBytes, rightStartOffset);
                  return (int) ed.computeSimilarity(firstOrdListIter, secondOrdListIter);
              }
              default: {
                  throw new TypeMismatchException(sourceLoc, BuiltinFunctions.EDIT_DISTANCE, 0, argType.serialize(),
                          ATypeTag.SERIALIZED_STRING_TYPE_TAG, ATypeTag.SERIALIZED_ORDEREDLIST_TYPE_TAG);
              }
  
          }
      }
  
      protected boolean checkArgTypes(ATypeTag typeTag1, ATypeTag typeTag2) throws HyracksDataException {
          if (typeTag1 != typeTag2) {
              throw new IncompatibleTypeException(sourceLoc, BuiltinFunctions.EDIT_DISTANCE, typeTag1.serialize(),
                      typeTag2.serialize());
          }
  
          // Since they are equal, check one tag is enough.
          if (typeTag1 != ATypeTag.STRING && typeTag1 != ATypeTag.ARRAY) { // could be an list
              throw new TypeMismatchException(sourceLoc, BuiltinFunctions.EDIT_DISTANCE, 0, typeTag1.serialize(),
                      ATypeTag.SERIALIZED_STRING_TYPE_TAG, ATypeTag.SERIALIZED_ORDEREDLIST_TYPE_TAG);
          }
  
          if (typeTag1 == ATypeTag.ARRAY) {
              itemTypeTag = EnumDeserializer.ATYPETAGDESERIALIZER
                      .deserialize(argPtr1.getByteArray()[argPtr1.getStartOffset() + 1]);
              if (itemTypeTag == ATypeTag.ANY) {
                  throw new UnsupportedItemTypeException(sourceLoc, BuiltinFunctions.EDIT_DISTANCE,
                          itemTypeTag.serialize());
              }
              itemTypeTag = EnumDeserializer.ATYPETAGDESERIALIZER
                      .deserialize(argPtr2.getByteArray()[argPtr2.getStartOffset() + 1]);
              if (itemTypeTag == ATypeTag.ANY) {
                  throw new UnsupportedItemTypeException(sourceLoc, BuiltinFunctions.EDIT_DISTANCE,
                          itemTypeTag.serialize());
              }
          }
          return true;
      }
  
      protected void writeResult(int ed) throws IOException {
          aInt64.setValue(ed);
          int64Serde.serialize(aInt64, out);
      }
  }
  