FSMBase.c

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void fsmbDebugPrint(string s)
{
#ifdef FSM_DEBUG
  PrintToRPT("" + s); // comment/uncomment to hide/see debug logs
#else
  //Print("" + s); // comment/uncomment to hide/see debug logs
#endif
}
void fsmbDebugSpam(string s)
{
#ifdef FSM_DEBUG_SPAM
  PrintToRPT("" + s); // comment/uncomment to hide/see debug logs
#else
  //Print("" + s); // comment/uncomment to hide/see debug logs
#endif
}
 
 
class FSMTransition<Class FSMStateBase, Class FSMEventBase, Class FSMActionBase, Class FSMGuardBase>
{
  ref FSMStateBase m_srcState;
  ref FSMEventBase m_event; // @NOTE: NULL event means "completion transition" in UML speak
  ref FSMStateBase m_dstState; // @NOTE: NULL dst state == UML terminate pseudonode
  ref FSMActionBase m_action;
  ref FSMGuardBase m_guard;
 
  void FSMTransition(FSMStateBase src, FSMEventBase e, FSMStateBase dst, FSMActionBase a = NULL, FSMGuardBase g = NULL)
  {
    m_srcState = src;
    m_event = e;
    m_dstState = dst;
    m_action = a;
    m_guard = g;
  }
};
 
enum ProcessEventResult
{
  FSM_OK,
  FSM_TERMINATED,
  FSM_ABORTED,
  FSM_NO_TRANSITION,
};
 
class FSMBase<Class FSMStateBase, Class FSMEventBase, Class FSMActionBase, Class FSMGuardBase>
{
  protected ref FSMStateBase m_state; 
  protected ref FSMStateBase m_initialState; 
  protected ref FSMEventBase m_initialEvent; 
  protected ref array<ref FSMTransition<FSMStateBase, FSMEventBase, FSMActionBase, FSMGuardBase>> m_transitions; 
 
  void FSMBase()
  {
    m_transitions = new array<ref FSMTransition<FSMStateBase, FSMEventBase, FSMActionBase, FSMGuardBase>>;
  }
 
  FSMStateBase GetCurrentState()
  {
    return m_state;
  }
 
  void SetInitialState(FSMStateBase initial_state)
  {
    m_initialState = initial_state;
  }
 
  void Start(FSMEventBase initial_event = NULL)
  {
    if (LogManager.IsInventoryHFSMLogEnable()) fsmbDebugPrint("[fsm] " + this.ToString() + "::Start(" + initial_event.ToString() + "), init_state=" + m_initialState.ToString());
 
    m_state = m_initialState;
    m_state.OnEntry(initial_event);
  }
 
  bool IsRunning() { return m_state != NULL; }
 
  void Terminate(FSMEventBase terminal_event = NULL)
  {
    if (IsRunning())
    {
      m_state.OnExit(terminal_event);
      m_state = NULL;
    }
  }
 
  void Update(float dt)
  {
    if (IsRunning())
      m_state.OnUpdate(dt);
  }
 
  void AddTransition(FSMTransition<FSMStateBase, FSMEventBase, FSMActionBase, FSMGuardBase> t)
  {
    m_transitions.Insert(t);
  }
 
  ProcessEventResult ProcessEvent(FSMEventBase e)
  {
    FSMStateBase curr_state = m_state;
 
    int count = m_transitions.Count();
    for (int i = 0; i < count; ++i)
    {
      FSMTransition<FSMStateBase, FSMEventBase, FSMActionBase, FSMGuardBase> row = m_transitions.Get(i);
      if (row.m_srcState.Type() == curr_state.Type() && row.m_event.Type() == e.Type())
      {
        FSMTransition<FSMStateBase, FSMEventBase, FSMActionBase, FSMGuardBase> t = m_transitions.Get(i);
        bool hasGuard = t.m_guard != NULL;
        if (!hasGuard || (hasGuard && t.m_guard.GuardCondition(e))) // 1) exec guard (if any)
        {
          ProcessLocalTransition(t, e); // 2) process transition allowed by guard
        }
      }
    }
    return ProcessEventResult.FSM_NO_TRANSITION;
  }
 
  protected ProcessEventResult ProcessLocalTransition(FSMTransition<FSMStateBase, FSMEventBase, FSMActionBase, FSMGuardBase> t, FSMEventBase e)
  {
    if (LogManager.IsInventoryHFSMLogEnable()) fsmbDebugPrint("[fsm] (local) state=" + t.m_srcState.ToString() + "-------- event=" + e.ToString() + "[G=" + t.m_guard.ToString() + "]/A=" + t.m_action.ToString() + " --------|> dst=" + t.m_dstState.ToString());
 
    m_state.OnExit(e); // 1) call onExit on old state
 
    if (t.m_action)
      t.m_action.Action(e); // 2) execute transition action (if any)
 
    m_state = t.m_dstState; // 3) change state to new
 
    if (t.m_dstState != NULL)
    {
      m_state.OnEntry(e); // 4a) call onEntry on new state
      return ProcessEventResult.FSM_OK;
    }
    else
    {
      if (LogManager.IsInventoryHFSMLogEnable()) fsmbDebugPrint("[fsm] terminating fsm: state=" + t.m_srcState.ToString() + " event=" + e.ToString());
      return ProcessEventResult.FSM_TERMINATED; // 4b) or terminate
    }
  }
};