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.celeborn.client.compress;
  
  import java.util.zip.Checksum;
  
  import net.jpountz.lz4.LZ4Compressor;
  import net.jpountz.lz4.LZ4Factory;
  import net.jpountz.xxhash.XXHashFactory;
  
  public class Lz4Compressor extends Lz4Trait implements Compressor {
    private final LZ4Compressor compressor;
    private final Checksum checksum;
    private byte[] compressedBuffer;
    private int compressedTotalSize;
  
    public Lz4Compressor(int blockSize) {
      this.compressor = LZ4Factory.fastestInstance().fastCompressor();
      checksum = XXHashFactory.fastestInstance().newStreamingHash32(DEFAULT_SEED).asChecksum();
      initCompressBuffer(blockSize);
    }
  
    @Override
    public void initCompressBuffer(int maxDestLength) {
      int compressedBlockSize = HEADER_LENGTH + maxDestLength;
      compressedBuffer = new byte[compressedBlockSize];
      System.arraycopy(MAGIC, 0, compressedBuffer, 0, MAGIC_LENGTH);
    }
  
    @Override
    public void compress(byte[] data, int offset, int length) {
      checksum.reset();
      checksum.update(data, offset, length);
      final int check = (int) checksum.getValue();
      int maxDestLength = compressor.maxCompressedLength(length);
      if (compressedBuffer.length - HEADER_LENGTH < maxDestLength) {
        initCompressBuffer(maxDestLength);
      }
      int compressedLength =
          compressor.compress(data, offset, length, compressedBuffer, HEADER_LENGTH);
      final int compressMethod;
      if (compressedLength >= length) {
        compressMethod = COMPRESSION_METHOD_RAW;
        compressedLength = length;
        System.arraycopy(data, offset, compressedBuffer, HEADER_LENGTH, length);
      } else {
        compressMethod = COMPRESSION_METHOD_LZ4;
      }
  
      compressedBuffer[MAGIC_LENGTH] = (byte) compressMethod;
      writeIntLE(compressedLength, compressedBuffer, MAGIC_LENGTH + 1);
      writeIntLE(length, compressedBuffer, MAGIC_LENGTH + 5);
      writeIntLE(check, compressedBuffer, MAGIC_LENGTH + 9);
  
      compressedTotalSize = HEADER_LENGTH + compressedLength;
    }
  
    @Override
    public int getCompressedTotalSize() {
      return compressedTotalSize;
    }
  
    @Override
    public byte[] getCompressedBuffer() {
      return compressedBuffer;
    }
  }
  