/tags/release-0.0.0-rc0/hive/external/serde/src/java/org/apache/hadoop/hive/serde2/lazy/LazyByte.java

/**
 * 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.serde2.lazy;

import org.apache.hadoop.hive.serde2.io.ByteWritable;
import org.apache.hadoop.hive.serde2.lazy.objectinspector.primitive.LazyByteObjectInspector;

/**
 * LazyObject for storing a value of Byte.
 * 
 * <p>
 * Part of the code is adapted from Apache Harmony Project.
 * 
 * As with the specification, this implementation relied on code laid out in <a
 * href="http://www.hackersdelight.org/">Henry S. Warren, Jr.'s Hacker's
 * Delight, (Addison Wesley, 2002)</a> as well as <a
 * href="http://aggregate.org/MAGIC/">The Aggregate's Magic Algorithms</a>.
 * </p>
 * 
 */
public class LazyByte extends
    LazyPrimitive<LazyByteObjectInspector, ByteWritable> {

  public LazyByte(LazyByteObjectInspector oi) {
    super(oi);
    data = new ByteWritable();
  }

  public LazyByte(LazyByte copy) {
    super(copy);
    data = new ByteWritable(copy.data.get());
  }

  @Override
  public void init(ByteArrayRef bytes, int start, int length) {
    try {
      data.set(parseByte(bytes.getData(), start, length, 10));
      isNull = false;
    } catch (NumberFormatException e) {
      isNull = true;
    }
  }

  /**
   * Parses the string argument as if it was a byte value and returns the
   * result. Throws NumberFormatException if the string does not represent a
   * single byte quantity.
   * 
   * @param bytes
   * @param start
   * @param length
   *          a UTF-8 encoded string representation of a single byte quantity.
   * @return byte the value represented by the argument
   * @throws NumberFormatException
   *           if the argument could not be parsed as a byte quantity.
   */
  public static byte parseByte(byte[] bytes, int start, int length) {
    return parseByte(bytes, start, length, 10);
  }

  /**
   * Parses the string argument as if it was a byte value and returns the
   * result. Throws NumberFormatException if the string does not represent a
   * single byte quantity. The second argument specifies the radix to use when
   * parsing the value.
   * 
   * @param bytes
   * @param start
   * @param length
   *          a UTF-8 encoded string representation of a single byte quantity.
   * @param radix
   *          the radix to use when parsing.
   * @return byte the value represented by the argument
   * @throws NumberFormatException
   *           if the argument could not be parsed as a byte quantity.
   */
  public static byte parseByte(byte[] bytes, int start, int length, int radix) {
    int intValue = LazyInteger.parseInt(bytes, start, length, radix);
    byte result = (byte) intValue;
    if (result == intValue) {
      return result;
    }
    throw new NumberFormatException();
  }

}