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 accord.utils;
  
  import java.util.zip.CRC32;
  
  public class CRCUtils
  {
      private static final int POLY = 0xedb88320;
  
      private CRCUtils() {}
  
      public static int crc32LittleEnding(int key)
      {
          CRC32 crc32c = new CRC32();
          crc32c.update(key);
          crc32c.update(key >> 8);
          crc32c.update(key >> 16);
          crc32c.update(key >> 24);
          return (int) crc32c.getValue();
      }
  
      public static int reverseCRC32LittleEnding(int c)
      {
          for (int i = 0; i < 32; i++)
          {
              c = (c >>> 31) == 0 ?
                  (c ^ POLY) << 1 | 1
                  : c << 1;
          }
          // flip bits
          c = c ^ 0xffffffff;
          return c;
      }
  }
  