lang/java/avro/src/main/java/org/apache/avro/file/BZip2Codec.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.avro.file;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;

import org.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream;
import org.apache.commons.compress.compressors.bzip2.BZip2CompressorOutputStream;

/** * Implements bzip2 compression and decompression. */
public class BZip2Codec extends Codec {

  public static final int DEFAULT_BUFFER_SIZE = 64 * 1024;
  private ByteArrayOutputStream outputBuffer;

  static class Option extends CodecFactory {
    @Override
    protected Codec createInstance() {
      return new BZip2Codec();
    }
  }

  @Override
  public String getName() { return DataFileConstants.BZIP2_CODEC; }

  @Override
  public ByteBuffer compress(ByteBuffer uncompressedData) throws IOException {

    ByteArrayOutputStream baos = getOutputBuffer(uncompressedData.remaining());
    BZip2CompressorOutputStream outputStream = new BZip2CompressorOutputStream(baos);

    try {
      outputStream.write(uncompressedData.array(),
                         uncompressedData.position(),
                         uncompressedData.remaining());
    } finally {
      outputStream.close();
    }

    ByteBuffer result = ByteBuffer.wrap(baos.toByteArray());
    return result;
  }

  @Override
  public ByteBuffer decompress(ByteBuffer compressedData) throws IOException {
    ByteArrayInputStream bais = new ByteArrayInputStream(compressedData.array());
    BZip2CompressorInputStream inputStream = new BZip2CompressorInputStream(bais);
    try {
      ByteArrayOutputStream baos = new ByteArrayOutputStream();

      byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];

      int readCount = -1;

      while ( (readCount = inputStream.read(buffer, compressedData.position(), buffer.length))> 0) {
        baos.write(buffer, 0, readCount);
      }

      ByteBuffer result = ByteBuffer.wrap(baos.toByteArray());
      return result;
    } finally {
      inputStream.close();
    }
  }

  @Override public int hashCode() { return getName().hashCode(); }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (getClass() != obj.getClass())
      return false;
    return true;
  }

  //get and initialize the output buffer for use.
  private ByteArrayOutputStream getOutputBuffer(int suggestedLength) {
    if (null == outputBuffer) {
      outputBuffer = new ByteArrayOutputStream(suggestedLength);
    }
    outputBuffer.reset();
    return outputBuffer;
  }


}