Revert "remove remnants of hinting mechanism"

This reverts commit 7de428233e.

Include/osrm/RouteParameters.h

@@ -78,11 +78,13 @@ struct RouteParameters
     bool compression;
     bool deprecatedAPI;
     bool uturn_default;
+    unsigned check_sum;
     short num_results;
     std::string service;
     std::string output_format;
     std::string jsonp_parameter;
     std::string language;
+    std::vector<std::string> hints;
     std::vector<bool> uturns;
     std::vector<FixedPointCoordinate> coordinates;
 };

data_structures/route_parameters.cpp

@@ -33,7 +33,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 RouteParameters::RouteParameters()
     : zoom_level(18), print_instructions(false), alternate_route(true), geometry(true),
-      compression(true), deprecatedAPI(false), uturn_default(false), num_results(1)
+      compression(true), deprecatedAPI(false), uturn_default(false), check_sum(-1), num_results(1)
 {
 }
 
@@ -77,7 +77,7 @@ void RouteParameters::setAllUTurns(const bool flag)
 
 void RouteParameters::setDeprecatedAPIFlag(const std::string &) { deprecatedAPI = true; }
 
-void RouteParameters::setChecksum(const unsigned sum) { }
+void RouteParameters::setChecksum(const unsigned sum) { check_sum = sum; }
 
 void RouteParameters::setInstructionFlag(const bool flag) { print_instructions = flag; }
 
@@ -92,11 +92,11 @@ void RouteParameters::setJSONpParameter(const std::string &parameter)
 
 void RouteParameters::addHint(const std::string &hint)
 {
-    // hints.resize(coordinates.size());
+    hints.resize(coordinates.size());
-    // if (!hints.empty())
+    if (!hints.empty())
-    // {
+    {
-    //     hints.back() = hint;
+        hints.back() = hint;
-    // }
+    }
 }
 
 void RouteParameters::setLanguage(const std::string &language_string)

plugins/hello_world.hpp

@@ -57,6 +57,8 @@ class HelloWorldPlugin final : public BasePlugin
         temp_string = cast::integral_to_string(routeParameters.zoom_level);
         json_result.values["zoom_level"] = temp_string;
 
+        temp_string = cast::integral_to_string(routeParameters.check_sum);
+        json_result.values["check_sum"] = temp_string;
         json_result.values["instructions"] = (routeParameters.print_instructions ? "yes" : "no");
         json_result.values["geometry"] = (routeParameters.geometry ? "yes" : "no");
         json_result.values["compression"] = (routeParameters.compression ? "yes" : "no");
@@ -84,6 +86,16 @@ class HelloWorldPlugin final : public BasePlugin
             ++counter;
         }
         json_result.values["locations"] = json_locations;
+        json_result.values["hint_count"] = routeParameters.hints.size();
+
+        JSON::Array json_hints;
+        counter = 0;
+        for (const std::string &current_hint : routeParameters.hints)
+        {
+            json_hints.values.push_back(current_hint);
+            ++counter;
+        }
+        json_result.values["hints"] = json_hints;
 
         JSON::render(reply.content, json_result);
     }

tools/simpleclient.cpp

@@ -90,10 +90,12 @@ int main(int argc, const char *argv[])
         route_parameters.alternate_route = true;    // get an alternate route, too
         route_parameters.geometry = true;           // retrieve geometry of route
         route_parameters.compression = true;        // polyline encoding
+        route_parameters.check_sum = UINT_MAX;      // see wiki
         route_parameters.service = "viaroute";      // that's routing
         route_parameters.output_format = "json";
         route_parameters.jsonp_parameter = ""; // set for jsonp wrapping
         route_parameters.language = "";        // unused atm
+        // route_parameters.hints.push_back(); // see wiki, saves I/O if done properly
 
         // start_coordinate
         route_parameters.coordinates.emplace_back(52.519930 * COORDINATE_PRECISION,