code: /**
   * 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.nutch.crawl;
  
  import java.util.Comparator;
  
  public class SignatureComparator implements Comparator<Object> {
    public int compare(Object o1, Object o2) {
      return _compare(o1, o2);
    }
    
    public static int _compare(Object o1, Object o2) {
      if (o1 == null && o2 == null) return 0;
      if (o1 == null) return -1;
      if (o2 == null) return 1;
      if (!(o1 instanceof byte[])) return -1;
      if (!(o2 instanceof byte[])) return 1;
      byte[] data1 = (byte[])o1;
      byte[] data2 = (byte[])o2;
      return _compare(data1, 0, data1.length, data2, 0, data2.length);
    }
    
    public static int _compare(byte[] data1, int s1, int l1, byte[] data2, int s2, int l2) {
      if (l2 > l1) return -1;
      if (l2 < l1) return 1;
      int res = 0;
      for (int i = 0; i < l1; i++) {
        res = (data1[s1 + i] - data2[s2 + i]);
        if (res != 0) return res;
      }
      return 0;
    }
  }
  