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.index.sai.disk.io;
  
  import org.apache.lucene.store.ChecksumIndexInput;
  import org.apache.lucene.store.IndexInput;
  
  import java.io.IOException;
  import java.util.zip.Checksum;
  
  /**
   * This implementation of {@link ChecksumIndexInput} is based on {@link org.apache.lucene.store.BufferedChecksumIndexInput}
   * but uses custom checksum algorithm instead of the hardcoded {@code CRC32} in {@code BufferedChecksumIndexInput}.
   *
   * @see org.apache.cassandra.index.sai.disk.io.IndexFileUtils.ChecksummingWriter
   */
  class BufferedChecksumIndexInput extends ChecksumIndexInput
  {
      final IndexInput delegate;
      final Checksum digest;
  
      public BufferedChecksumIndexInput(IndexInput delegate, Checksum digest)
      {
          super("BufferedChecksumIndexInput(" + delegate + ')');
          this.delegate = delegate;
          this.digest = digest;
      }
  
      public byte readByte() throws IOException
      {
          byte b = this.delegate.readByte();
          this.digest.update(b);
          return b;
      }
  
      public void readBytes(byte[] b, int offset, int len) throws IOException
      {
          this.delegate.readBytes(b, offset, len);
          this.digest.update(b, offset, len);
      }
  
      public long getChecksum()
      {
          return this.digest.getValue();
      }
  
      public void close() throws IOException
      {
          this.delegate.close();
      }
      public long getFilePointer()
      {
          return this.delegate.getFilePointer();
      }
  
      public long length()
      {
          return this.delegate.length();
      }
  
      public IndexInput clone()
      {
          throw new UnsupportedOperationException();
      }
  
      public IndexInput slice(String sliceDescription, long offset, long length) throws IOException
      {
          throw new UnsupportedOperationException();
      }
  }
  