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
   *
   *     https://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.IOException;
  import java.nio.Buffer;
  import java.nio.ByteBuffer;
  import java.util.zip.CRC32;
  
  import org.xerial.snappy.Snappy;
  
  /** * Implements Snappy compression and decompression. */
  public class SnappyCodec extends Codec {
    private final CRC32 crc32 = new CRC32();
  
    static class Option extends CodecFactory {
      static {
        // if snappy isn't available, this will throw an exception which we
        // can catch so we can avoid registering this codec
        Snappy.getNativeLibraryVersion();
      }
  
      @Override
      protected Codec createInstance() {
        return new SnappyCodec();
      }
    }
  
    private SnappyCodec() {
    }
  
    @Override
    public String getName() {
      return DataFileConstants.SNAPPY_CODEC;
    }
  
    @Override
    public ByteBuffer compress(ByteBuffer in) throws IOException {
      int offset = computeOffset(in);
      ByteBuffer out = ByteBuffer.allocate(Snappy.maxCompressedLength(in.remaining()) + 4);
      int size = Snappy.compress(in.array(), offset, in.remaining(), out.array(), 0);
      crc32.reset();
      crc32.update(in.array(), offset, in.remaining());
      out.putInt(size, (int) crc32.getValue());
  
      ((Buffer) out).limit(size + 4);
  
      return out;
    }
  
    @Override
    public ByteBuffer decompress(ByteBuffer in) throws IOException {
      int offset = computeOffset(in);
      ByteBuffer out = ByteBuffer.allocate(Snappy.uncompressedLength(in.array(), offset, in.remaining() - 4));
      int size = Snappy.uncompress(in.array(), offset, in.remaining() - 4, out.array(), 0);
      ((Buffer) out).limit(size);
  
      crc32.reset();
      crc32.update(out.array(), 0, size);
      if (in.getInt(in.limit() - 4) != (int) crc32.getValue())
        throw new IOException("Checksum failure");
  
      return out;
    }
  
    @Override
    public int hashCode() {
      return getName().hashCode();
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj)
        return true;
      return obj != null && obj.getClass() == getClass();
    }
  }
  