Pass generic template class as functor parameter

I want to improve the following code snippet:

THNNetIPInfoIter last = std::unique(fist, end, HNInfoIPComparator());

where currently HNInfoIPComparator() is implemented as following:

// equal comparator
class HNInfoIPComparator
{
    public:
      bool operator()(const THNNetIPInfo &a, const THNNetIPInfo &b);
      bool operator()(const SDK::TIPAddressDescription &a, const SDK::TIPAddressDescription &b);
      bool operator()(const THNNetIPInfo &a, const SDK::TIPAddressDescription &b);
      bool operator()(const SDK::TIPAddressDescription &a, const THNNetIPInfo &b);
};

The reason for this comparator definition is that it might be used with another STL algorithms, like std::set_difference and should handle case when ranges has different types.

The problem is that I have to write huge amount of very similar comparators and it is easy to be entangled with which comparator to use.

I want to write the following snippet:

template<typename SDKClass, typename IDLClass>
class equal {
public:
  bool operator()(const IDLClass &a, const IDLClass &b) {
      if (strcmp(a.ipaddr.in(), b.ipaddr.in())) {
          return false;
      }
      return true;
  }

  bool operator()(const SDKClass &a, const SDKClass &b) {
      if (strcmp(a.ip_address().c_str(), b.ip_address().c_str())) {
          return false;
      }
      return true;
  }

  bool operator()(const IDLClass &a, const SDKClass &b) {
      if (strcmp(a.ipaddr.in(), b.ip_address().c_str())) {
          return false;
      }
      return true;
  }

  bool operator()(const SDKClass &a, const IDLClass &b) {
      if (strcmp(a.ip_address().c_str(), b.ipaddr.in())) {
          return false;
      }
      return true;
  }
};

So HNInfoIPComparator() would be generated depending on types passed as its arguments inside std::unique function.

Therefore I want to pass to std::unique templated functor (class). Is it possible to do that and how?

Also I want to handle case when functor contains some internal data, which are used for comparisons

Most important code samples:

// Automatically generated structure from IDL specification
// Basically simple structure
struct  THNNetIPInfo
{     
    typedef THNNetIPInfo_var _var_type;
    typedef THNNetIPInfo_out _out_type;

    static void _tao_any_destructor (void *);
    ::TAO::String_Manager ipaddr;
    ::TAO::String_Manager netmask;
};

// THNNetIPInfoIter - class external iterator
// which was written manually
typedef Util::CorbaSeqIter<THNNetIPInfoList, THNNetIPInfo> THNNetIPInfoIter;

// THNNetIPInfoList - also automatically generated class
// from IDL specification, list of THNNetIPInfo elements
THNNetIPInfoList list(...);
THNNetIPInfoIter first(&list, 0);
THNNetIPInfoIter end(&list, list.length());