Allow distinguishing PLIB joysticks by index (count)

This gives a simple way to have different config files for multiple
identical devices, such as the Saitek/Logitech throttle-quadrant

src/Input/FGDeviceConfigurationMap.cxx

@@ -49,14 +49,9 @@ FGDeviceConfigurationMap::FGDeviceConfigurationMap( const string& relative_path,
 {
   // scan for over-ride configurations, loaded via joysticks.xml, etc
   for (auto preloaded : nodePath->getChildren(nodeName)) {
-    // allow specifying a serial number in the override
-    std::string serial = preloaded->getStringValue("serial-number");
-    if (!serial.empty()) {
-      serial = "::" + serial;
-    }
-    
+    std::string suffix = computeSuffix(preloaded);
     for (auto nameProp : preloaded->getChildren("name")) {
-      overrideDict[nameProp->getStringValue() + serial] = preloaded;
+      overrideDict[nameProp->getStringValue() + suffix] = preloaded;
     } // of names iteration
   } // of defined overrides iteration
   
@@ -64,6 +59,22 @@ FGDeviceConfigurationMap::FGDeviceConfigurationMap( const string& relative_path,
   scan_dir( SGPath(globals->get_fg_root(), relative_path));
 }
 
+std::string FGDeviceConfigurationMap::computeSuffix(SGPropertyNode_ptr node)
+{
+    if (node->hasChild("serial-number")) {
+        return std::string("::") + node->getStringValue("serial-number");
+    }
+
+    // allow specifying a device number / index in the override
+    if (node->hasChild("device-number")) {
+        std::ostringstream os;
+        os << "_" << node->getIntValue("device-number");
+        return os.str();
+    }
+
+    return{};
+}
+
 FGDeviceConfigurationMap::~FGDeviceConfigurationMap()
 {
 }
@@ -156,14 +167,10 @@ void FGDeviceConfigurationMap::refreshCacheForFile(const SGPath& path)
     return;
   }
   
-  std::string serial = n->getStringValue("serial-number");
-  if (!serial.empty()) {
-    serial = "::" + serial;
-  }
-  
+  std::string suffix = computeSuffix(n);
   string_list names;
   for (auto nameProp : n->getChildren("name")) {
-    const string name = nameProp->getStringValue() + serial;
+    const string name = nameProp->getStringValue() + suffix;
     names.push_back(name);
     // same comment as readCachedData: only insert if not already present
     if (namePathMap.find(name) == namePathMap.end()) {

src/Input/FGDeviceConfigurationMap.hxx

@@ -54,6 +54,8 @@ private:
   void readCachedData(const SGPath& path);
   void refreshCacheForFile(const SGPath& path);
   
+  std::string computeSuffix(SGPropertyNode_ptr node);
+
   typedef std::map<std::string, SGPropertyNode_ptr> NameNodeMap;
 // dictionary of over-ridden configurations, where the config data
 // was explicitly loaded and shoudl be picked over a file search

src/Input/FGJoystickInput.cxx

@@ -133,11 +133,16 @@ void FGJoystickInput::init()
       SG_LOG(SG_INPUT, SG_INFO, "Looking for bindings for joystick \"" << name << '"');
       SGPropertyNode_ptr named;
 
-      if (configMap.hasConfiguration(name)) {
+      // allow distinguishing duplicated devices by the name
+      string indexedName = computeDeviceIndexName(name, i);
+      if (configMap.hasConfiguration(indexedName)) {
+          named = configMap.configurationForDeviceName(indexedName);
+          std::string source = named->getStringValue("source", "user defined");
+          SG_LOG(SG_INPUT, SG_INFO, "... found joystick: " << source);
+      } else if (configMap.hasConfiguration(name)) {
         named = configMap.configurationForDeviceName(name);
         std::string source = named->getStringValue("source", "user defined");
         SG_LOG(SG_INPUT, SG_INFO, "... found joystick: " << source);
-
       } else if ((named = configMap.configurationForDeviceName("default"))) {
         std::string source = named->getStringValue("source", "user defined");
         SG_LOG(SG_INPUT, SG_INFO, "No config found for joystick \"" << name
@@ -154,6 +159,21 @@ void FGJoystickInput::init()
   }
 }
 
+std::string FGJoystickInput::computeDeviceIndexName(const std::string& name,
+                                                    int lastIndex) const
+{
+    int index = 0;
+    for (int i = 0; i < lastIndex; i++) {
+        if (joysticks[i].plibJS && (joysticks[i].plibJS->getName() == name)) {
+            ++index;
+        }
+    }
+
+    std::ostringstream os;
+    os << name << "_" << index;
+    return os.str();
+}
+
 void FGJoystickInput::reinit() {
   SG_LOG(SG_INPUT, SG_DEBUG, "Re-Initializing joystick bindings");
   _remove(false);

src/Input/FGJoystickInput.hxx

@@ -50,7 +50,16 @@ public:
   static const int MAX_JOYSTICK_BUTTONS = 32;
 
 private:
- 
+  /**
+   * @brief computeDeviceIndexName - compute the name including the index, based
+   * on the number of identically named devices. This is used to allow multiple
+   * different files for identical hardware, especially throttles
+   * @param name - the base joystick name
+   * @param lastIndex - don't check names at this index or above. Needed to
+   * ensure we only check as far as the joystick we are currently processing
+   * @return
+   */
+  std::string computeDeviceIndexName(const std::string &name, int lastIndex) const;
     
    void _remove(bool all);
    SGPropertyNode_ptr status_node;
@@ -91,7 +100,7 @@ private:
     
   joystick joysticks[MAX_JOYSTICKS];
   void updateJoystick(int index, joystick* joy, double dt);
-    
+
 };
 
 #endif