#include <vector>
#include <iostream>
#include <stdlib.h> /* atoi */
#include <sstream>

using namespace std;

string int2string(int num)
{
  ostringstream os;
  os << num;
  return os.str();
}

string ip2string(vector<short> ip)
{
  string ret;
  for (vector<short>::iterator i = ip.begin(); i != ip.end(); ++i)
    ret += (i != ip.begin() ? "." : "") + int2string(*i);
  return ret;
}
string ip2string(vector<unsigned char> ip)
{
  string ret;
  for (vector<unsigned char>::iterator i = ip.begin(); i != ip.end(); ++i)
    ret += (i != ip.begin() ? "." : "") + int2string(*i);
  return ret;
}

int IPv4Loopup(const vector<vector<unsigned char > >* addrList, vector<vector<unsigned char > >* matches, string* mask)
{
  if (!addrList) // no list to search
    return -1;
  if (!matches) // no place to store matches
    return -1;
  if (mask->length() == 0) // no mask
    return -1;

  // parse the mask into something we can use
  vector<short> useableMask;
  size_t pos = 0;
  size_t posEnd = 0;
  while (posEnd != string::npos)
  {
    posEnd = mask->find(".", pos);
    string byte = mask->substr(pos, posEnd-pos);
    if (byte == "*")
      useableMask.push_back(-1);
    else
      useableMask.push_back(atoi(byte.c_str()));
    pos = posEnd + 1;
  }

  // search through addrList for ones matching mask, if so, put it in matches
  // return the number of matches
  int numFound = 0;
  for (vector<vector<unsigned char> >::const_iterator it = addrList->begin(); it != addrList->end(); ++it)
  {
    vector<unsigned char> ip = *it;
    bool match = true;
    for (int i = 0; i < ip.size(); ++i)
    {
      if (useableMask[i] == -1) // wild card, match away
        continue;
      if (useableMask[i] != ip[i]) // no match
      {
        match = false;
        break;
      }
    }
    if (match)
    {
      numFound++;
      matches->push_back(ip);
    }
  }
  return numFound;
}

int main()
{
  vector<vector<unsigned char > > list;
  vector<vector<unsigned char > > matches;

  vector<unsigned char> tmp;
  tmp.push_back(192);
  tmp.push_back(168);
  tmp.push_back(100);
  tmp.push_back(101);
  list.push_back(tmp);

  tmp.clear();
  tmp.push_back(192);
  tmp.push_back(168);
  tmp.push_back(100);
  tmp.push_back(102);
  list.push_back(tmp);

  tmp.clear();
  tmp.push_back(127);
  tmp.push_back(0);
  tmp.push_back(0);
  tmp.push_back(1);
  list.push_back(tmp);

  string mask = "192.168.*.*";

  cout << "Found " << IPv4Loopup(&list, &matches, &mask) << " matches" << endl;
  cout << "Mask: " << mask << endl;
  cout << "Matches: ";
  for (vector<vector<unsigned char> >::iterator i = matches.begin(); i != matches.end(); ++i)
  {
    cout << ip2string(*i) << " ";
  }
  cout << endl;
  return 0;
}