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.Map;
  import java.util.function.Supplier;
  import java.util.zip.Checksum;
  
  import scala.Option;
  
  import com.google.common.collect.ImmutableMap;
  import net.jpountz.lz4.LZ4Factory;
  import net.jpountz.lz4.LZ4FastDecompressor;
  import net.jpountz.xxhash.XXHashFactory;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class Lz4Decompressor extends Lz4Trait implements Decompressor {
    private static final Logger logger = LoggerFactory.getLogger(Lz4Decompressor.class);
  
    private final LZ4FastDecompressor decompressor;
    private final Checksum checksum;
  
    private final Map<String, Supplier<XXHashFactory>> xxHashFactories =
        ImmutableMap.of(
            "JNI",
            XXHashFactory::nativeInstance,
            "JAVASAFE",
            XXHashFactory::safeInstance,
            "JAVAUNSAFE",
            XXHashFactory::unsafeInstance);
  
    public Lz4Decompressor(Option<String> xxHashInstance) {
      decompressor = LZ4Factory.fastestInstance().fastDecompressor();
      checksum = getXXHashFactory(xxHashInstance).newStreamingHash32(DEFAULT_SEED).asChecksum();
    }
  
    @Override
    public int getOriginalLen(byte[] src) {
      return readIntLE(src, MAGIC_LENGTH + 5);
    }
  
    @Override
    public int decompress(byte[] src, byte[] dst, int dstOff) {
      int compressionMethod = src[MAGIC_LENGTH] & 0xFF;
      int compressedLen = readIntLE(src, MAGIC_LENGTH + 1);
      int originalLen = readIntLE(src, MAGIC_LENGTH + 5);
      int check = readIntLE(src, MAGIC_LENGTH + 9);
  
      switch (compressionMethod) {
        case COMPRESSION_METHOD_RAW:
          System.arraycopy(src, HEADER_LENGTH, dst, dstOff, originalLen);
          break;
        case COMPRESSION_METHOD_LZ4:
          int compressedLen2 = decompressor.decompress(src, HEADER_LENGTH, dst, dstOff, originalLen);
          if (compressedLen != compressedLen2) {
            logger.error(
                "Compressed length corrupted! expected: {}, actual: {}.",
                compressedLen,
                compressedLen2);
            return -1;
          }
      }
  
      checksum.reset();
      checksum.update(dst, dstOff, originalLen);
      if ((int) checksum.getValue() != check) {
        logger.error("Checksum not equal! expected: {}, actual: {}.", check, checksum.getValue());
        return -1;
      }
  
      return originalLen;
    }
  
    private XXHashFactory getXXHashFactory(Option<String> xxHashInstance) {
      return xxHashInstance.isDefined() && xxHashFactories.containsKey(xxHashInstance.get())
          ? xxHashFactories.get(xxHashInstance.get()).get()
          : XXHashFactory.fastestInstance();
    }
  }
  