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.functions;
  
  import java.io.DataOutput;
  import java.io.IOException;
  
  import org.apache.asterix.builders.OrderedListBuilder;
  import org.apache.asterix.common.annotations.MissingNullInOutFunction;
  import org.apache.asterix.om.exceptions.ExceptionUtil;
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
  import org.apache.asterix.om.types.AOrderedListType;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
  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.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.UTF8StringPointable;
  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;
  import org.apache.hyracks.util.string.UTF8StringUtil;
  
  @MissingNullInOutFunction
  public class StringSplitDescriptor extends AbstractScalarFunctionDynamicDescriptor {
  
      private static final long serialVersionUID = 1L;
  
      public static final IFunctionDescriptorFactory FACTORY = StringSplitDescriptor::new;
  
      @Override
      public IScalarEvaluatorFactory createEvaluatorFactory(final IScalarEvaluatorFactory[] args) {
          return new IScalarEvaluatorFactory() {
              private static final long serialVersionUID = 1L;
  
              @Override
              public IScalarEvaluator createScalarEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
                  return new IScalarEvaluator() {
                      // Argument evaluators.
                      private final IScalarEvaluator stringEval = args[0].createScalarEvaluator(ctx);
                      private final IScalarEvaluator patternEval = args[1].createScalarEvaluator(ctx);
  
                      // Argument pointers.
                      private final IPointable argString = new VoidPointable();
                      private final IPointable argPattern = new VoidPointable();
                      private final UTF8StringPointable argStrPtr = new UTF8StringPointable();
                      private final UTF8StringPointable argPatternPtr = new UTF8StringPointable();
  
                      // For an output string item.
                      private final ArrayBackedValueStorage itemStorge = new ArrayBackedValueStorage();
                      private final DataOutput itemOut = itemStorge.getDataOutput();
                      private final byte[] tempLengthArray = new byte[5];
  
                      // For the output list of strings.
                      private final AOrderedListType intListType = new AOrderedListType(BuiltinType.ASTRING, null);
                      private final OrderedListBuilder listBuilder = new OrderedListBuilder();
                      private final ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
                      private final DataOutput out = resultStorage.getDataOutput();
  
                      @Override
                      public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
                          try {
                              resultStorage.reset();
                              // Calls argument evaluators.
                              stringEval.evaluate(tuple, argString);
                              patternEval.evaluate(tuple, argPattern);
  
                              if (PointableHelper.checkAndSetMissingOrNull(result, argString, argPattern)) {
                                  return;
                              }
  
                              // Gets the bytes of the source string.
                              byte[] srcString = argString.getByteArray();
                              int srcOffset = argString.getStartOffset();
                              int srcLen = argString.getLength();
                              // Type check for the first argument.
                              if (srcString[srcOffset] != ATypeTag.SERIALIZED_STRING_TYPE_TAG) {
                                  PointableHelper.setNull(result);
                                  ExceptionUtil.warnTypeMismatch(ctx, sourceLoc, getIdentifier(), srcString[srcOffset], 0,
                                          ATypeTag.STRING);
                                  return;
                              }
  
                              // Gets the bytes of the pattern string.
                              byte[] patternString = argPattern.getByteArray();
                              int patternOffset = argPattern.getStartOffset();
                              int patternLen = argPattern.getLength();
                              // Type check for the second argument.
                              if (patternString[patternOffset] != ATypeTag.SERIALIZED_STRING_TYPE_TAG) {
                                  PointableHelper.setNull(result);
                                  ExceptionUtil.warnTypeMismatch(ctx, sourceLoc, getIdentifier(),
                                          patternString[patternOffset], 1, ATypeTag.STRING);
                                  return;
                              }
  
                              // Sets the UTF8 String pointables.
                              argStrPtr.set(srcString, srcOffset + 1, srcLen - 1);
                              argPatternPtr.set(patternString, patternOffset + 1, patternLen - 1);
  
                              // Gets the string length of the source string.
                              int inputStringLen = UTF8StringUtil.getUTFLength(srcString, srcOffset + 1);
                              int inputStringStart =
                                      srcOffset + 1 + UTF8StringUtil.getNumBytesToStoreLength(inputStringLen);
                              // Gets the string length of the pattern string.
                              int inputPatternLen = UTF8StringUtil.getUTFLength(patternString, patternOffset + 1);
                              // Handles the case that the pattern is "".
                              boolean emptyStringPattern = inputPatternLen == 0;
  
                              // Builds a list of strings.
                              listBuilder.reset(intListType);
                              int itemStrStart = 0;
                              int nextMatchStart;
                              while (itemStrStart < inputStringLen && (nextMatchStart =
                                      UTF8StringPointable.find(argStrPtr, argPatternPtr, false, itemStrStart)) >= 0) {
                                  // Adds an item string.
                                  addItemString(srcString, inputStringStart, itemStrStart,
                                          emptyStringPattern ? nextMatchStart + 1 : nextMatchStart);
                                  itemStrStart = nextMatchStart + (emptyStringPattern ? 1 : inputPatternLen);
                              }
                              if (!emptyStringPattern) {
                                  addItemString(srcString, inputStringStart, itemStrStart, inputStringLen);
                              }
                              listBuilder.write(out, true);
                              result.set(resultStorage);
                          } catch (IOException e1) {
                              throw HyracksDataException.create(e1);
                          }
                      }
  
                      private void addItemString(byte[] srcString, int inputStringStart, int itemStartOffset,
                              int nextMatchStart) throws IOException {
                          int itemLen = nextMatchStart - itemStartOffset;
                          int cbytes = UTF8StringUtil.encodeUTF8Length(itemLen, tempLengthArray, 0);
                          itemStorge.reset();
                          itemOut.writeByte(ATypeTag.SERIALIZED_STRING_TYPE_TAG);
                          itemOut.write(tempLengthArray, 0, cbytes);
                          if (itemLen > 0) {
                              itemOut.write(srcString, inputStringStart + itemStartOffset, itemLen);
                          }
                          listBuilder.addItem(itemStorge);
                      }
                  };
              }
          };
      }
  
      @Override
      public FunctionIdentifier getIdentifier() {
          return BuiltinFunctions.STRING_SPLIT;
      }
  }
  