diff --git a/library/include/mobilisis/calculate_price.h b/library/include/mobilisis/calculate_price.h
index 8c4dcfb..277d9d5 100644
--- a/library/include/mobilisis/calculate_price.h
+++ b/library/include/mobilisis/calculate_price.h
@@ -5,6 +5,7 @@
 #include <inttypes.h>
 
 #include <QString>
+#include <QDateTime>
 
 #ifdef WIN32
 #ifdef CALCULATE_LIBRARY_EXPORTS
@@ -20,9 +21,9 @@ class Configuration;
 
 typedef Configuration parking_tariff_t;
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+//#ifdef __cplusplus
+//extern "C" {
+//#endif
 
 struct CALCULATE_LIBRARY_API price_t {
     uint32_t units;
@@ -41,6 +42,7 @@ struct CALCULATE_LIBRARY_API CalcState {
         NEGATIVE_PARING_TIME,
         INVALID_START_DATE,
         WRONG_PARAM_VALUES,
+        WRONG_ISO_TIME_FORMAT,
         ABOVE_MAX_PARKING_TIME,
         BELOW_MIN_PARKING_TIME,
         BELOW_MIN_PARKING_PRICE,
@@ -92,6 +94,8 @@ struct CALCULATE_LIBRARY_API CalcState {
         case State::INVALID_START_DATE:
             s = "INVALID_START_DATE";
             break;
+        case State::WRONG_ISO_TIME_FORMAT:
+            s = "WRONG_ISO_TIME_FORMAT";
         }
         return s + ":" + m_desc;
     }
@@ -111,13 +115,25 @@ CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
                                             time_t end_parking_time,
                                             struct price_t *price);
 
+CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
+                                            parking_tariff_t *tariff,
+                                            QDateTime const &start_parking_time,
+                                            QDateTime const &end_parking_time,
+                                            struct price_t *price);
+
 CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
                                             parking_tariff_t *tariff,
                                             time_t start_parking_time,
                                             double cost,
                                             QString &duration);
-#ifdef __cplusplus
-} // extern "C"
-#endif
+
+CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
+                                            parking_tariff_t *tariff,
+                                            QDateTime const &start_parking_time,
+                                            double cost,
+                                            QDateTime &ticketEndTime);
+//#ifdef __cplusplus
+//} // extern "C"
+//#endif
 
 #endif // CALCULATE_PRICE_H
diff --git a/library/src/calculate_price.cpp b/library/src/calculate_price.cpp
index 2d3f4a5..c3eef53 100644
--- a/library/src/calculate_price.cpp
+++ b/library/src/calculate_price.cpp
@@ -139,6 +139,57 @@ CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
     return calcState.set(CalcState::State::SUCCESS);
 }
 
+CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
+                                            parking_tariff_t *tariff,
+                                            QDateTime const &start_parking_time,
+                                            QDateTime const &end_parking_time,
+                                            struct price_t *price) {
+    CalcState calcState;
+    double minMin = tariff->PaymentOption.find(PaymentOption::Option1)->second.pop_min_time;
+    double maxMin = tariff->PaymentOption.find(PaymentOption::Option1)->second.pop_max_time;
+
+    int const duration = (end_parking_time.toSecsSinceEpoch() -
+                          start_parking_time.toMSecsSinceEpoch()) / 60;
+
+    if (duration < 0) {
+        calcState.setDesc(QString("end=%1, start=%2")
+                            .arg(end_parking_time.toString(Qt::ISODate),
+                                 start_parking_time.toString(Qt::ISODate)));
+        return calcState.set(CalcState::State::NEGATIVE_PARING_TIME);
+    }
+    if (duration > maxMin) {
+        calcState.setDesc(QString("duration=%1, maxMin=%2").arg(duration, maxMin));
+        return calcState.set(CalcState::State::ABOVE_MAX_PARKING_TIME);
+    }
+    if (duration < minMin) {
+        calcState.setDesc(QString("duration=%1, minMin=%2").arg(duration, minMin));
+        return calcState.set(CalcState::State::BELOW_MIN_PARKING_TIME);
+    }
+    if (duration == 0) {
+        memset(price, 0x00, sizeof(*price));
+        return calcState.set(CalcState::State::SUCCESS);
+    }
+
+    if (start_parking_time.isValid()) {
+        QString cs = start_parking_time.toString(Qt::ISODate);
+        double cost = calculator.GetCostFromDuration(
+                        tariff, PaymentOption::Option1,
+                        cs.toLocal8Bit().constData(),
+                        duration, false, true);
+        double minCost = tariff->PaymentOption.find(PaymentOption::Option1)->second.pop_min_price;
+        if (cost < minCost) {
+            calcState.setDesc(QString("minCost=%1, cost=%2").arg(minCost, cost));
+            return calcState.set(CalcState::State::BELOW_MIN_PARKING_PRICE);
+        }
+        price->units = cost;
+        price->netto = cost;
+    } else {
+        return calcState.set(CalcState::State::INVALID_START_DATE);
+    }
+
+    return calcState.set(CalcState::State::SUCCESS);
+}
+
 CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
                                             parking_tariff_t *tariff,
                                             time_t start_parking_time,
@@ -154,6 +205,35 @@ CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
         duration = calculator.GetDurationFromCost(tariff, PaymentOption::Option1,
                                                   cs.toLocal8Bit().constData(),
                                                   price, false, true).c_str();
+        QDateTime d = QDateTime::fromString(duration);
+        if (!d.isValid()) {
+            calcState.setDesc(QString("ticketEndTime=%1").arg(duration));
+            return calcState.set(CalcState::State::WRONG_ISO_TIME_FORMAT);
+        }
+    } else {
+        return calcState.set(CalcState::State::INVALID_START_DATE);
+    }
+
+    return calcState.set(CalcState::State::SUCCESS);
+}
+
+CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
+                                            parking_tariff_t *tariff,
+                                            QDateTime const &start_parking_time,
+                                            double price,
+                                            QDateTime &ticketEndTime) {
+    CalcState calcState;
+    if (start_parking_time.isValid()) {
+        QString cs = start_parking_time.toString(Qt::ISODate);
+        QString endTime = calculator.GetDurationFromCost(
+                                        tariff, PaymentOption::Option1,
+                                        cs.toLocal8Bit().constData(),
+                                        price, false, true).c_str();
+        ticketEndTime = QDateTime::fromString(endTime);
+        if (!ticketEndTime.isValid()) {
+            calcState.setDesc(QString("ticketEndTime=%1").arg(endTime));
+            return calcState.set(CalcState::State::WRONG_ISO_TIME_FORMAT);
+        }
     } else {
         return calcState.set(CalcState::State::INVALID_START_DATE);
     }