onepad: add an unique identifier

plugins/onepad/GamePad.cpp

@@ -35,3 +35,26 @@ void GamePad::DoRumble(unsigned type, unsigned pad)
         s_vgamePad[id]->Rumble(type, pad);
     }
 }
+
+size_t GamePad::index_to_uid(int index)
+{
+    if ((index >= 0) && (index < (int)s_vgamePad.size()))
+        return s_vgamePad[index]->GetUniqueIdentifier();
+    else
+        return 0;
+}
+
+int GamePad::uid_to_index(size_t uid)
+{
+    for (int i = 0; i < (int)s_vgamePad.size(); ++i) {
+        if (s_vgamePad[i]->GetUniqueIdentifier() == uid)
+            return i;
+    }
+
+    // Current uid wasn't found maybe the pad was unplugged
+    // Fallback to the first pad which more friendly than nothing
+    if (!s_vgamePad.empty())
+        return 0;
+
+    return -1;
+}

plugins/onepad/GamePad.h

@@ -57,6 +57,11 @@ public:
         return m_deadzone;
     }
 
+    virtual size_t GetUniqueIdentifier() = 0;
+
+    static size_t index_to_uid(int index);
+    static int uid_to_index(size_t uid);
+
     bool IsProperlyInitialized()
     {
         return m_no_error;

plugins/onepad/SDL/joystick.cpp

@@ -151,6 +151,9 @@ JoystickInfo::JoystickInfo(int id)
         return;
     }
 
+    std::hash<std::string> hash_me;
+    m_unique_id = hash_me(std::string(guid));
+
     // Default haptic effect
     SDL_HapticEffect effects[NB_EFFECT];
     for (int i = 0; i < NB_EFFECT; i++) {
@@ -207,6 +210,11 @@ const char *JoystickInfo::GetName()
     return SDL_JoystickName(SDL_GameControllerGetJoystick(m_controller));
 }
 
+size_t JoystickInfo::GetUniqueIdentifier()
+{
+    return m_unique_id;
+}
+
 bool JoystickInfo::TestForce(float strength = 0.60)
 {
     // This code just use standard rumble to check that SDL handles the pad correctly! --3kinox

plugins/onepad/SDL/joystick.h

@@ -52,8 +52,11 @@ public:
 
     virtual void UpdateGamePadState();
 
+    virtual size_t GetUniqueIdentifier();
+
 private:
     SDL_GameController *m_controller;
     SDL_Haptic *m_haptic;
     std::array<int, NB_EFFECT> m_effects_id;
+    size_t m_unique_id;
 };