http://blog.youkuaiyun.com/NetLinux
std::string strPath("C://Windows//System32//drivers");
std::string strZune = "drivers";
int pos = 0;
boost::iterator_range<std::string::iterator> retFind= boost::ifind_first(strPath, strZune);
pos = retFind.begin() - strPath.begin();
strPath.erase(retFind.end(), strPath.end());