Implement get_calculator()

library/include/mobilisis/calculate_price.h

@@ -111,6 +111,9 @@ int CALCULATE_LIBRARY_API get_zone_nr(int zone = -1);
 
 int CALCULATE_LIBRARY_API compute_next_timestep(parking_tariff_t *tariff, int currentTimeMinutes, int UpDown);
 
+class Calculator;
+Calculator CALCULATE_LIBRARY_API *get_calculator();
+
 CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(       // deprecated
                                             parking_tariff_t *tariff,
                                             time_t start_parking_time,

library/include/mobilisis/configuration.h

@@ -30,6 +30,7 @@
 using namespace std;
 using namespace rapidjson;
 
+class Calculator;
 class Configuration
 {
 public:

library/src/calculate_price.cpp

@@ -11,6 +11,10 @@
 
 static Calculator calculator;
 
+Calculator CALCULATE_LIBRARY_API *get_calculator() {
+    return &calculator;
+}
+
 int CALCULATE_LIBRARY_API get_zone_nr(int zone)
 {
     if(zone > -1) return zone;