if (config.checksumSeed != null) { config.strongSum.update(config.checksumSeed); }
   hashSearch(byte[] block, int off, int len) {      Integer weakSum = new Integer(config.weakSum.getValue());      if (hashtable.containsKey(weakSum.intValue())) {         if (hashtable.containsKey(weakSum)) {            config.strongSum.reset();            config.strongSum.update(block, off, len);            byte[] digest = new byte[config.strongSumLength];            System.arraycopy(config.strongSum.digest(), 0, digest, 0,               digest.length);            return (Long) hashtable.get(               new ChecksumPair(weakSum.intValue(), digest));         }      }      return null;   }