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.CRC32;
  import java.util.zip.Checksum;
  
  import com.github.luben.zstd.Zstd;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class ZstdDecompressor extends ZstdTrait implements Decompressor {
    private static final Logger logger = LoggerFactory.getLogger(ZstdDecompressor.class);
    private final Checksum checksum;
  
    public ZstdDecompressor() {
      checksum = new CRC32();
    }
  
    @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_ZSTD:
          int originalLen2 =
              (int)
                  Zstd.decompressByteArray(
                      dst, dstOff, originalLen, src, HEADER_LENGTH, compressedLen);
          if (originalLen != originalLen2) {
            logger.error(
                "Original length corrupted! expected: {}, actual: {}.", originalLen, originalLen2);
            return -1;
          }
          break;
        default:
          logger.error("Unknown compression method whose decimal number is {} .", compressionMethod);
          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;
    }
  }
  