Added experimental FSM template.

src/experimental/fsm.h

@@ -0,0 +1,231 @@
+
+#ifndef __ETL_FSM__
+#define __ETL_FSM__
+
+#include <stdint.h>
+
+#include "../array.h"
+#include "../nullptr.h"
+#include "../error_handler.h"
+#include "../exception.h"
+
+#undef ETL_FILE
+#define ETL_FILE "34"
+
+namespace etl
+{
+  typedef uint32_t fsm_state_id_t;
+  typedef uint32_t fsm_event_id_t;
+
+  //***************************************************************************
+  class fsm_exception : public etl::exception
+  {
+  public:
+
+    fsm_exception(string_type what, string_type file_name, numeric_type line_number)
+      : etl::exception(what, file_name, line_number)
+    {
+    }
+  };
+
+  //***************************************************************************
+  class fsm_nullstate_exception : public etl::fsm_exception
+  {
+  public:
+
+    fsm_nullstate_exception(string_type file_name, numeric_type line_number)
+      : etl::fsm_exception(ETL_ERROR_TEXT("fsm:null state", ETL_FILE"A"), file_name, line_number)
+    {
+    }
+  };
+
+  //***************************************************************************
+  class fsm_state_id_exception : public etl::fsm_exception
+  {
+  public:
+
+    fsm_state_id_exception(string_type file_name, numeric_type line_number)
+      : etl::fsm_exception(ETL_ERROR_TEXT("fsm:state id", ETL_FILE"B"), file_name, line_number)
+    {
+    }
+  };
+
+  //***************************************************************************
+  class ifsm_event
+  {
+  public:
+
+    virtual etl::fsm_event_id_t get_event_id() const = 0;
+  };
+
+  //***************************************************************************
+  template <const etl::fsm_event_id_t EVENT_ID_>
+  class fsm_event : public etl::ifsm_event
+  {
+  public:
+
+    enum
+    {
+      EVENT_ID = EVENT_ID_
+    };
+
+    //*******************************************
+    etl::fsm_event_id_t get_event_id() const
+    {
+      return EVENT_ID;
+    }
+  };
+
+  //***************************************************************************
+  class ifsm_state
+  {
+  public:
+
+    virtual etl::fsm_state_id_t on_event(const etl::ifsm_event& event) = 0;
+    virtual etl::fsm_state_id_t get_state_id() const = 0;
+
+  protected:
+
+    virtual void on_enter_state() {};
+    virtual void on_exit_state() {};
+  };
+
+  //***************************************************************************
+  // To be COG generated.
+  template <typename TState, const etl::fsm_state_id_t STATE_ID_, typename T1>
+  class fsm_state : public ifsm_state
+  {
+  public:
+
+    enum
+    {
+      THIS_STATE_ID = STATE_ID_
+    };
+
+    //*******************************************
+    etl::fsm_state_id_t on_event(const etl::ifsm_event& event)
+    {
+      etl::fsm_state_id_t new_state_id;
+      etl::fsm_event_id_t id = event.get_event_id();
+
+      switch (id)
+      {
+        case T1::EVENT_ID: new_state_id = static_cast<TState&>(*this).on_event(static_cast<const T1&>(event)); break;
+        default: new_state_id = static_cast<TState&>(*this).on_unknown_event(event); break;
+      }
+
+      return new_state_id;
+    }
+
+    //*******************************************
+    etl::fsm_state_id_t get_state_id() const
+    {
+      return THIS_STATE_ID;
+    }
+  };
+
+  //***************************************************************************
+  template <const etl::fsm_state_id_t MAX_STATES>
+  class fsm
+  {
+  public:
+
+    //*******************************************
+    fsm()
+    {
+      state_list.fill(nullptr);
+    }
+
+    //*******************************************
+    void start()
+    {
+      p_state = state_list[0];
+      ETL_ASSERT(p_state != nullptr, ETL_ERROR(etl::fsm_nullstate_exception));
+
+      p_state->on_enter_state();
+    }
+
+    //*******************************************
+    void add_state(etl::ifsm_state& state)
+    {
+      ETL_ASSERT(state.get_state_id() < MAX_STATES, ETL_ERROR(etl::fsm_state_id_exception));
+      state_list[state.get_state_id()] = &state;
+    }
+
+    //*******************************************
+    void on_event(const etl::ifsm_event& event)
+    {
+      etl::fsm_state_id_t next_state_id = p_state->on_event(event);
+      ETL_ASSERT(next_state_id < MAX_STATES, ETL_ERROR(etl::fsm_state_id_exception));
+
+      // Have we changed state?
+      if (next_state_id != p_state->get_state_id())
+      {
+        p_state->on_exit_state();
+
+        p_state = state_list[next_state_id];
+        ETL_ASSERT(p_state != nullptr, ETL_ERROR(etl::fsm_nullstate_exception));
+
+        p_state->on_enter_state();
+      }
+    }
+
+    //*******************************************
+    etl::fsm_state_id_t get_state_id() const
+    {
+      return p_state->get_state_id();
+    }
+
+    //*******************************************
+    ifsm_state& get_state()
+    {
+      return *p_state;
+    }
+
+    //*******************************************
+    const ifsm_state& get_state() const
+    {
+      return *p_state;
+    }
+
+  private:
+
+    etl::ifsm_state* p_state;
+    etl::array<etl::ifsm_state*, MAX_STATES> state_list;
+  };
+}
+
+#undef ETL_FILE
+
+// class Start : public etl::fsm_event<0>
+// {
+
+// };
+
+// class Idle : public etl::fsm_state<Idle, 0, Start>
+// {
+// public:
+
+//   etl::fsm_state_id_t on_event(const Start& event)
+//   {
+//     return 1;
+//   }
+
+//   etl::fsm_state_id_t on_unknown_event(const etl::ifsm_event& event)
+//   {
+//     return THIS_STATE_ID;
+//   }
+// };
+
+// etl::fsm<3> machine;
+
+// void F()
+// {
+//   Idle idle;
+
+//   machine.add_state(idle);
+//   machine.start();
+//   machine.on_event(Start());
+// }
+
+#endif