content: /*
   * Licensed 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 io.airlift.compress.v3.gzip;
  
  import io.airlift.compress.v3.hadoop.HadoopInputStream;
  
  import java.io.BufferedInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.zip.GZIPInputStream;
  
  import static java.lang.Math.max;
  import static java.util.Objects.requireNonNull;
  
  class JdkGzipHadoopInputStream
          extends HadoopInputStream
  {
      private final byte[] oneByte = new byte[1];
      private final GZIPInputStream input;
  
      public JdkGzipHadoopInputStream(InputStream input, int bufferSize)
              throws IOException
      {
          this.input = new GZIPInputStream(new GzipBufferedInputStream(input, bufferSize), bufferSize);
      }
  
      @Override
      public int read()
              throws IOException
      {
          int length = input.read(oneByte, 0, 1);
          if (length < 0) {
              return length;
          }
          return oneByte[0] & 0xFF;
      }
  
      @Override
      public int read(byte[] output, int offset, int length)
              throws IOException
      {
          return input.read(output, offset, length);
      }
  
      @Override
      public void resetState()
      {
          throw new UnsupportedOperationException("resetState not supported for gzip");
      }
  
      @Override
      public void close()
              throws IOException
      {
          input.close();
      }
  
      // workaround for https://bugs.openjdk.org/browse/JDK-8081450
      private static class GzipBufferedInputStream
              extends BufferedInputStream
      {
          public GzipBufferedInputStream(InputStream input, int bufferSize)
          {
              super(requireNonNull(input, "input is null"), bufferSize);
          }
  
          @Override
          public int available()
                  throws IOException
          {
              // GZIPInputStream thinks the stream is complete if this returns zero
              return max(1, super.available());
          }
      }
  }
  