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.ByteBuffer;
  
  /**
   * Interface for Avro-supported compression codecs for data files.
   *
   * Note that Codec objects may maintain internal state (e.g. buffers) and are
   * not thread safe.
   */
  public abstract class Codec {
    /** Name of the codec; written to the file's metadata. */
    public abstract String getName();
  
    /** Compresses the input data */
    public abstract ByteBuffer compress(ByteBuffer uncompressedData) throws IOException;
  
    /** Decompress the data */
    public abstract ByteBuffer decompress(ByteBuffer compressedData) throws IOException;
  
    /**
     * Codecs must implement an equals() method. Two codecs, A and B are equal if:
     * the result of A and B decompressing content compressed by A is the same AND
     * the result of A and B decompressing content compressed by B is the same
     **/
    @Override
    public abstract boolean equals(Object other);
  
    /**
     * Codecs must implement a hashCode() method that is consistent with equals().
     */
    @Override
    public abstract int hashCode();
  
    @Override
    public String toString() {
      return getName();
    }
  
    // Codecs often reference the array inside a ByteBuffer. Compute the offset
    // to the start of data correctly in the case that our ByteBuffer
    // is a slice() of another.
    protected static int computeOffset(ByteBuffer data) {
      return data.arrayOffset() + data.position();
    }
  }
  