static String quote(String path){
    byte[] _path=str2byte(path);
    int count=0;
    for(int i=0;i<_path.length; i++){
      byte b=_path[i];
      if(b=='\\' || b=='?' || b=='*')
        count++;
    }
    if(count==0)
      return path;
    byte[] _path2=new byte[_path.length+count];
    for(int i=0, j=0; i<_path.length; i++){
      byte b=_path[i];
      if(b=='\\' || b=='?' || b=='*'){
        _path2[j++]='\\';
      }
      _path2[j++]=b;
    }
    return byte2str(_path2);
  }