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.io.util;
  
  import java.io.IOException;
  
  import org.apache.cassandra.io.compress.BufferType;
  import org.apache.cassandra.utils.ByteBufferUtil;
  
  class ChecksummedRebufferer extends BufferManagingRebufferer
  {
      private final DataIntegrityMetadata.ChecksumValidator validator;
  
      ChecksummedRebufferer(ChannelProxy channel, DataIntegrityMetadata.ChecksumValidator validator)
      {
          super(new SimpleChunkReader(channel, channel.size(), BufferType.ON_HEAP, validator.chunkSize));
          this.validator = validator;
      }
  
      @Override
      public BufferHolder rebuffer(long desiredPosition)
      {
          if (desiredPosition != offset + buffer.position())
              validator.seek(desiredPosition);
  
          // align with buffer size, as checksums were computed in chunks of buffer size each.
          offset = alignedPosition(desiredPosition);
          source.readChunk(offset, buffer);
  
          try
          {
              validator.validate(ByteBufferUtil.getArray(buffer), 0, buffer.remaining());
          }
          catch (IOException e)
          {
              throw new CorruptFileException(e, channel().filePath());
          }
  
          return this;
      }
  
      @Override
      public void close()
      {
          try
          {
              source.close();
          }
          finally
          {
              validator.close();
          }
      }
  
      @Override
      long alignedPosition(long desiredPosition)
      {
          return (desiredPosition / buffer.capacity()) * buffer.capacity();
      }
  }
  