static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned short numzeros)
{
  hash->val[wpos] = (int)hashval;
  if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval];
  hash->head[hashval] = wpos;

  hash->zeros[wpos] = numzeros;
  if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros];
  hash->headz[numzeros] = wpos;
}
Unknown