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.common.annotations.MissingNullInOutFunction;
  import org.apache.asterix.om.base.AMutableInt32;
  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.ATypeTag;
  import org.apache.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
  import org.apache.asterix.runtime.evaluators.common.ArgumentUtils;
  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.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 StringRepeatDescriptor extends AbstractScalarFunctionDynamicDescriptor {
      private static final long serialVersionUID = 1L;
      public static final IFunctionDescriptorFactory FACTORY = StringRepeatDescriptor::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 IScalarEvaluator evalString = args[0].createScalarEvaluator(ctx);
                      private IScalarEvaluator evalStart = args[1].createScalarEvaluator(ctx);
  
                      // Argument pointers.
                      private IPointable argString = new VoidPointable();
                      private IPointable argNumber = new VoidPointable();
                      private final AMutableInt32 mutableInt = new AMutableInt32(0);
  
                      // For outputting the result.
                      private ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
                      private DataOutput out = resultStorage.getDataOutput();
                      private byte[] tempLengthArray = new byte[5];
  
                      @Override
                      public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
                          resultStorage.reset();
  
                          // Calls argument evaluators.
                          evalString.evaluate(tuple, argString);
                          evalStart.evaluate(tuple, argNumber);
  
                          if (PointableHelper.checkAndSetMissingOrNull(result, argString, argNumber)) {
                              return;
                          }
  
                          // Gets the repeating times.
                          byte[] bytes = argNumber.getByteArray();
                          int offset = argNumber.getStartOffset();
                          if (!ArgumentUtils.setInteger(ctx, sourceLoc, getIdentifier(), 1, bytes, offset, mutableInt)) {
                              PointableHelper.setNull(result);
                              return;
                          }
                          int repeatingTimes = mutableInt.getIntegerValue();
                          // Checks repeatingTimes. It should be a non-negative value.
                          if (repeatingTimes < 0) {
                              PointableHelper.setNull(result);
                              ExceptionUtil.warnNegativeValue(ctx, sourceLoc, getIdentifier(), 1, repeatingTimes);
                              return;
                          }
  
                          // Gets the input string.
                          bytes = argString.getByteArray();
                          offset = argString.getStartOffset();
                          // Checks the type of the string argument.
                          if (bytes[offset] != ATypeTag.SERIALIZED_STRING_TYPE_TAG) {
                              PointableHelper.setNull(result);
                              ExceptionUtil.warnTypeMismatch(ctx, sourceLoc, getIdentifier(), bytes[offset], 0,
                                      ATypeTag.STRING);
                              return;
                          }
  
                          // Calculates the result string length.
                          int inputLen = UTF8StringUtil.getUTFLength(bytes, offset + 1);
                          int resultLen = Math.multiplyExact(inputLen, repeatingTimes); // Can throw overflow exception.
                          int cbytes = UTF8StringUtil.encodeUTF8Length(resultLen, tempLengthArray, 0);
  
                          // Writes the output string.
                          int inputStringStart = offset + 1 + UTF8StringUtil.getNumBytesToStoreLength(inputLen);
                          try {
                              out.writeByte(ATypeTag.SERIALIZED_STRING_TYPE_TAG);
                              out.write(tempLengthArray, 0, cbytes);
                              for (int numRepeats = 0; numRepeats < repeatingTimes; ++numRepeats) {
                                  out.write(bytes, inputStringStart, inputLen);
                              }
                          } catch (IOException e) {
                              throw HyracksDataException.create(e);
                          }
                          result.set(resultStorage);
                      }
                  };
              }
          };
      }
  
      @Override
      public FunctionIdentifier getIdentifier() {
          return BuiltinFunctions.STRING_REPEAT;
      }
  }
  