/**
 * 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.hadoop.hive.ql.udf;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDFUtils;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;

/**
 * UDFLength.
 *
 */
@Description(name = "length",
    value = "_FUNC_(str | binary) - Returns the length of str or number of bytes in binary data",
    extended = "Example:\n"
    + "  > SELECT _FUNC_('Facebook') FROM src LIMIT 1;\n" + "  8")
public class UDFLength extends UDF {
  private final IntWritable result = new IntWritable();

  public IntWritable evaluate(Text s) {
    if (s == null) {
      return null;
    }

    byte[] data = s.getBytes();
    int len = 0;
    for (int i = 0; i < s.getLength(); i++) {
      if (GenericUDFUtils.isUtfStartByte(data[i])) {
        len++;
      }
    }

    result.set(len);
    return result;
  }

  public IntWritable evaluate(BytesWritable bw){
    if (bw == null){
      return null;

}
    result.set(bw.getLength());
    return result;
  }
}