mapreduce/src/contrib/raid/src/java/org/apache/hadoop/raid/XOREncoder.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.raid;

import java.io.OutputStream;
import java.io.InputStream;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.util.Progressable;

public class XOREncoder extends Encoder {
  public static final Log LOG = LogFactory.getLog(
                                  "org.apache.hadoop.raid.XOREncoder");
  public XOREncoder(
    Configuration conf, int stripeSize) {
    super(conf, stripeSize, 1);
  }

  @Override
  protected void encodeStripe(
    InputStream[] blocks,
    long stripeStartOffset,
    long blockSize,
    OutputStream[] outs,
    Progressable reporter) throws IOException {
    LOG.info("Peforming XOR ");
    ParityInputStream parityIn =
      new ParityInputStream(blocks, blockSize, readBufs[0], writeBufs[0]);
    try {
      parityIn.drain(outs[0], reporter);
    } finally {
      parityIn.close();
    }
  }
}