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.types.ATypeTag;
  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.api.exceptions.SourceLocation;
  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.data.std.util.GrowableArray;
  import org.apache.hyracks.data.std.util.UTF8StringBuilder;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  @MissingNullInOutFunction
  class SubstringEval extends AbstractScalarEval {
  
      private final ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
      private final DataOutput out = resultStorage.getDataOutput();
      private final IPointable argString = new VoidPointable();
      private final IPointable argStart = new VoidPointable();
      private final IPointable argLen = new VoidPointable();
      private final IEvaluatorContext ctx;
      private final IScalarEvaluator evalString;
      private final IScalarEvaluator evalStart;
      private final IScalarEvaluator evalLen;
      private final int baseOffset;
  
      private final GrowableArray array = new GrowableArray();
      private final UTF8StringBuilder builder = new UTF8StringBuilder();
      private final UTF8StringPointable string = new UTF8StringPointable();
      private final AMutableInt32 mutableInt32 = new AMutableInt32(0);
  
      SubstringEval(IEvaluatorContext ctx, IScalarEvaluatorFactory[] args, FunctionIdentifier functionIdentifier,
              SourceLocation sourceLoc, int baseOffset) throws HyracksDataException {
          super(sourceLoc, functionIdentifier);
          this.ctx = ctx;
          evalString = args[0].createScalarEvaluator(ctx);
          evalStart = args[1].createScalarEvaluator(ctx);
          evalLen = args[2].createScalarEvaluator(ctx);
  
          this.baseOffset = baseOffset;
      }
  
      @Override
      public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
          resultStorage.reset();
          evalString.evaluate(tuple, argString);
          evalStart.evaluate(tuple, argStart);
          evalLen.evaluate(tuple, argLen);
  
          if (PointableHelper.checkAndSetMissingOrNull(result, argString, argStart, argLen)) {
              return;
          }
  
          byte[] bytes = argStart.getByteArray();
          int offset = argStart.getStartOffset();
          if (!ArgumentUtils.setInteger(ctx, srcLoc, funID, 1, bytes, offset, mutableInt32)) {
              PointableHelper.setNull(result);
              return;
          }
          int start = mutableInt32.getIntegerValue();
  
          bytes = argLen.getByteArray();
          offset = argLen.getStartOffset();
          if (!ArgumentUtils.setInteger(ctx, srcLoc, funID, 2, bytes, offset, mutableInt32)) {
              PointableHelper.setNull(result);
              return;
          }
          int len = mutableInt32.getIntegerValue();
  
          bytes = argString.getByteArray();
          offset = argString.getStartOffset();
          int length = argString.getLength();
          if (bytes[offset] != ATypeTag.SERIALIZED_STRING_TYPE_TAG) {
              PointableHelper.setNull(result);
              ExceptionUtil.warnTypeMismatch(ctx, srcLoc, funID, bytes[offset], 0, ATypeTag.STRING);
              return;
          }
          string.set(bytes, offset + 1, length - 1);
          array.reset();
          try {
              int actualStart = start >= 0 ? Math.max(start - baseOffset, 0) : string.getStringLength() + start;
              boolean success = UTF8StringPointable.substr(string, actualStart, len, builder, array);
              if (success) {
                  out.writeByte(ATypeTag.SERIALIZED_STRING_TYPE_TAG);
                  out.write(array.getByteArray(), 0, array.getLength());
                  result.set(resultStorage);
              } else {
                  PointableHelper.setNull(result);
              }
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
      }
  }
  