int ELFhash (char *key)
{
    unsigned long h = 0;
    while(*key)
    {
       h = (h<<4) + *key++;
       unsigned long g = h & 0xf0000000L;
       if (g)
          h ^= g>>24;
       h &= ~g;
    }
    return h%M; //M为hash表的大小

}