interpretation of empty value strings in json

bsp_q7s/devices/startracker/ArcsecJsonParamBase.cpp

@@ -17,12 +17,19 @@ ReturnValue_t ArcsecJsonParamBase::getParam(const std::string name, std::string&
     for (json::iterator it = set.begin(); it != set.end(); ++it) {
         if ((*it)[arcseckeys::NAME] == name) {
             value = (*it)[arcseckeys::VALUE];
+            convertEmpty(value);
             return RETURN_OK;
         }
     }
     return PARAM_NOT_EXISTS;
 }
 
+void ArcsecJsonParamBase::convertEmpty(std::string& value) {
+    if (value == "") {
+        value = "0";
+    }
+}
+
 void ArcsecJsonParamBase::addfloat(const std::string value, uint8_t* buffer) {
     float param = std::stof(value);
     std::memcpy(buffer, &param, sizeof(param));