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.cassandra.hints;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.nio.channels.FileChannel;
  import java.util.zip.CRC32;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import org.apache.cassandra.io.compress.ICompressor;
  
  import org.apache.cassandra.io.util.File;
  
  public class CompressedHintsWriter extends HintsWriter
  {
      // compressed and uncompressed size is stored at the beginning of each compressed block
      static final int METADATA_SIZE = 8;
  
      private final ICompressor compressor;
  
      private volatile ByteBuffer compressionBuffer = null;
  
      public CompressedHintsWriter(File directory, HintsDescriptor descriptor, File file, FileChannel channel, int fd, CRC32 globalCRC)
      {
          super(directory, descriptor, file, channel, fd, globalCRC);
          compressor = descriptor.createCompressor();
          assert compressor != null;
      }
  
      protected void writeBuffer(ByteBuffer bb) throws IOException
      {
          int originalSize = bb.remaining();
          int estimatedSize = compressor.initialCompressedBufferLength(originalSize) + METADATA_SIZE;
  
          if (compressionBuffer == null || compressionBuffer.capacity() < estimatedSize)
          {
              compressionBuffer = compressor.preferredBufferType().allocate(estimatedSize);
          }
          compressionBuffer.clear();
  
          compressionBuffer.position(METADATA_SIZE);
          compressor.compress(bb, compressionBuffer);
          int compressedSize = compressionBuffer.position() - METADATA_SIZE;
  
          compressionBuffer.rewind();
          compressionBuffer.putInt(originalSize);
          compressionBuffer.putInt(compressedSize);
          compressionBuffer.rewind();
          compressionBuffer.limit(compressedSize + METADATA_SIZE);
          super.writeBuffer(compressionBuffer);
      }
  
      @VisibleForTesting
      ICompressor getCompressor()
      {
          return compressor;
      }
  }
  