www.pudn.com > FSM_program.zip > HSM.H

/** hsm.h -- Hierarchical State Machine interface 
 * M. Samek, 01/07/00 
 */ 
#ifndef hsm_h 
#define hsm_h 

typedef int Event; 
struct Msg { 
  Event evt; 
}; 
 
class Hsm;                         /* forward declaration */ 
typedef Msg const *(Hsm::*EvtHndlr)(Msg const *); 
 
class State { 
  State *super;                  /* pointer to superstate */ 
  EvtHndlr hndlr;             /* state's handler function */ 
  char const *name; 
public: 
  State(char const *name, State *super, EvtHndlr hndlr); 
private: 
  Msg const *onEvent(Hsm *ctx, Msg const *msg) { 
    return (ctx->*hndlr)(msg); 
  } 
  friend class Hsm; 
}; 
 
class Hsm {      /* Hierarchical State Machine base class */ 
  char const *name;             /* pointer to static name */ 
  State *curr;                           /* current state */ 
protected: 
  State *next;  /* next state (non 0 if transition taken) */ 
  State top;                     /* top-most state object */ 
public: 
  Hsm(char const *name, EvtHndlr topHndlr);       /* Ctor */ 
  void onStart();        /* enter and start the top state */ 
  void onEvent(Msg const *msg); /* "state machine engine" */ 
protected: 
  unsigned char toLCA_(State *target); 
  void exit_(unsigned char toLca); 
  State *STATE_CURR() { return curr; } 
  void STATE_START(State *target) { 
    assert(next == 0); 
    next = target; 
  } 
# define STATE_TRAN(target_) if (1) {\ 
    static unsigned char toLca_ = 0;\ 
    assert(next == 0);\ 
    if (toLca_ == 0)\ 
      toLca_ = toLCA_(target_);\ 
    exit_(toLca_);\ 
    next = (target_);\ 
  } else ((void)0) 
};  
 
#define START_EVT ((Event)(-1)) 
#define ENTRY_EVT ((Event)(-2)) 
#define EXIT_EVT  ((Event)(-3)) 

#endif /* hsm_h */