typedef int Event;
typedef struct {
Event evt;
} Msg;
typedef struct Hsm Hsm;
typedef Msg const *(*EvtHndlr)(Hsm*, Msg const*);
typedef struct State State;
struct State {
State *super; /* pointer to superstate */
EvtHndlr hndlr; /* state's handler function */
char const *name;
};
void StateCtor(State *me, char const *name,
State *super, EvtHndlr hndlr);
#define StateOnEvent(me_, ctx_, msg_)\
(*(me_)->hndlr)((ctx_), (msg_))
struct Hsm { /* Hierarchical State Machine base class */
char const *name; /* pointer to static name */
State *curr; /* current state */
State *next; /* next state (non 0 if transition taken) */
State top; /* top-most state object */
};
void HsmCtor(Hsm *me, char const *name, EvtHndlr topHndlr);
void HsmOnStart(Hsm
*me); /* enter and start the top state */
void HsmOnEvent(Hsm *me, Msg const *msg); /* "HSM engine" */
/* protected: */
unsigned char HsmToLCA_(Hsm *me, State *target);
void HsmExit_(Hsm *me, unsigned char toLca);
#define STATE_CURR(me_) (((Hsm *)me_)->curr)
#define STATE_START(me_, target_) \
(assert((((Hsm *)me_)->next == 0),\
((Hsm *)me_)->next = (target_))
#define STATE_TRAN(me_, target_) if (1) { \
static unsigned char toLca_ = 0; \
assert(((Hsm *)me_)->next == 0);\
if (toLca_ == 0) \
toLca_ = HsmToLCA_((Hsm *)(me_), (target_));\
HsmExit_((Hsm *)(me_), toLca_);\
((Hsm *)(me_))->next = (target_);\
} else ((void)0)
#define START_EVT ((Event)(-1))
#define ENTRY_EVT ((Event)(-2))
#define EXIT_EVT ((Event)(-3))
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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))
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