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.net;
  
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.util.zip.CRC32;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.channel.ChannelHandler;
  import net.jpountz.lz4.LZ4Compressor;
  import net.jpountz.lz4.LZ4Factory;
  import org.apache.cassandra.io.compress.BufferType;
  import org.apache.cassandra.utils.ByteBufferUtil;
  
  import static org.apache.cassandra.utils.Crc.*;
  
  /**
   * Please see {@link FrameDecoderLZ4} for description of the framing produced by this encoder.
   */
  @ChannelHandler.Sharable
  public
  class FrameEncoderLZ4 extends FrameEncoder
  {
      public static final FrameEncoderLZ4 fastInstance = new FrameEncoderLZ4(LZ4Factory.fastestInstance().fastCompressor());
  
      private final LZ4Compressor compressor;
  
      private FrameEncoderLZ4(LZ4Compressor compressor)
      {
          this.compressor = compressor;
      }
  
      private static final int HEADER_LENGTH = 8;
      public static final int HEADER_AND_TRAILER_LENGTH = 12;
  
      private static void writeHeader(ByteBuffer frame, boolean isSelfContained, long compressedLength, long uncompressedLength)
      {
          long header5b = compressedLength | (uncompressedLength << 17);
          if (isSelfContained)
              header5b |= 1L << 34;
  
          long crc = crc24(header5b, 5);
  
          long header8b = header5b | (crc << 40);
          if (frame.order() == ByteOrder.BIG_ENDIAN)
              header8b = Long.reverseBytes(header8b);
  
          frame.putLong(0, header8b);
      }
  
      public ByteBuf encode(boolean isSelfContained, ByteBuffer in)
      {
          ByteBuffer frame = null;
          try
          {
              int uncompressedLength = in.remaining();
              if (uncompressedLength >= 1 << 17)
                  throw new IllegalArgumentException("Maximum uncompressed payload size is 128KiB");
  
              int maxOutputLength = compressor.maxCompressedLength(uncompressedLength);
              frame = bufferPool.getAtLeast(HEADER_AND_TRAILER_LENGTH + maxOutputLength, BufferType.OFF_HEAP);
  
              int compressedLength = compressor.compress(in, in.position(), uncompressedLength, frame, HEADER_LENGTH, maxOutputLength);
  
              if (compressedLength >= uncompressedLength)
              {
                  ByteBufferUtil.copyBytes(in, in.position(), frame, HEADER_LENGTH, uncompressedLength);
                  compressedLength = uncompressedLength;
                  uncompressedLength = 0;
              }
  
              writeHeader(frame, isSelfContained, compressedLength, uncompressedLength);
  
              CRC32 crc = crc32();
              frame.position(HEADER_LENGTH);
              frame.limit(compressedLength + HEADER_LENGTH);
              crc.update(frame);
  
              int frameCrc = (int) crc.getValue();
              if (frame.order() == ByteOrder.BIG_ENDIAN)
                  frameCrc = Integer.reverseBytes(frameCrc);
              int frameLength = compressedLength + HEADER_AND_TRAILER_LENGTH;
  
              frame.limit(frameLength);
              frame.putInt(frameCrc);
              frame.position(0);
  
              bufferPool.putUnusedPortion(frame);
              return GlobalBufferPoolAllocator.wrap(frame);
          }
          catch (Throwable t)
          {
              if (frame != null)
                  bufferPool.put(frame);
              throw t;
          }
          finally
          {
              bufferPool.put(in);
          }
      }
  }
  