Added FSM and Game State Manager

src/game/StateMachine.cpp

@@ -0,0 +1,84 @@
+#include <assert.h>
+#include "StateMachine.h"
+// =============================================================================
+// Do NOT modify this file, instead make custom changes in the GameStateManager
+// or create your own StateMachine including and implementing this header
+// ============================================================================= 
+ 
+StateMachine::StateMachine(unsigned char maxStates) :
+    currentState(0),
+    _maxStates(maxStates),
+    _eventGenerated(false),
+    _pEventData(NULL)
+{
+}    
+ 
+// generates an external event. called once per external event 
+// to start the state machine executing
+void StateMachine::ExternalEvent(unsigned char newState, 
+                                 EventData* pData)
+{
+    // if we are supposed to ignore this event
+    if (newState == EVENT_IGNORED) {
+        // just delete the event data, if any
+        if (pData)  
+            delete pData;
+    }
+    else {
+		// TODO - capture software lock here for thread-safety if necessary
+
+        // generate the event and execute the state engine
+        InternalEvent(newState, pData); 
+        StateEngine();     
+
+		// TODO - release software lock here 
+    }
+}
+
+// generates an internal event. called from within a state 
+// function to transition to a new state
+void StateMachine::InternalEvent(unsigned char newState, 
+                                 EventData* pData)
+{
+	if (pData == NULL)
+		pData = new EventData();
+
+    _pEventData = pData;
+    _eventGenerated = true;
+    currentState = newState;
+}
+
+// the state engine executes the state machine states
+void StateMachine::StateEngine(void)
+{
+    EventData* pDataTemp = NULL;
+ 
+    // while events are being generated keep executing states
+    while (_eventGenerated) {         
+        pDataTemp = _pEventData;  // copy of event data pointer
+        _pEventData = NULL;       // event data used up, reset ptr
+        _eventGenerated = false;  // event used up, reset flag
+ 
+        assert(currentState < _maxStates);
+
+		// get state map
+        const StateStruct* pStateMap = GetStateMap();
+
+        // execute the state passing in event data, if any
+        (this->*pStateMap[currentState].pStateFunc)(pDataTemp);
+ 
+        // if event data was used, then delete it
+        if (pDataTemp) {
+            delete pDataTemp;
+            pDataTemp = NULL;
+        }
+    }
+}
+
+// unsigned char getCurrentState()
+// {
+//     const StateStruct* pStateMap = GetStateMap();
+//     this->*pStateMap[currentState];
+//     unsigned char state = StateMachine.currentState;
+//     return state;
+// }