state.h File Reference

state library api More...

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Typedefs
typedef int(*	StateFunc )(void *data)
	Default type for a state function.

Functions
struct StateMachine *	state_newmachine ()
	state_newmachine instanciate a new empty machine More...
void	state_free (struct StateMachine *p)
	state_free release resource of a machine allocated with state_newmachine More...
int	state_add_transition (struct StateMachine *machine, StateFunc from, int value, StateFunc to)
	state_add_transition Add a new transition into the machine More...
int	state_start (struct StateMachine *machine, StateFunc start, void *data)
	state_start run a state machine More...

Detailed Description

state library api

The state library is really simple. First you must create a machine using the state_newmachine function. This will return an handler to an empty machine. Then you can register any state and transition using state_add_transition function. A state is a pointer to a function, transition are associated to int. State return value are used to select the next state function that will be run. Finally, you can start your machine by giving the initial state function and a pointer that will be passed to all state function. At last, release the resources associated to the machine using state_free.

#include <state.h>
#include <stdio.h>

int a(void *p){
  static int counter=0;
  counter+=1;
  printf("a: %d\n",counter);
  return counter;
}

int b(void *p){
  printf("b\n");
  return 0;
}

int main(){
  struct StateMachine *machine;
  machine=state_newmachine();
  state_add_transition(machine,a,1,b);
  state_add_transition(machine,b,0,a);
  state_add_transition(machine,a,2,NULL);
  state_start(machine,a,NULL);
  state_free(machine);
}

Function Documentation

int state_add_transition	(	struct StateMachine *	machine,
		StateFunc	from,
		int	value,
		StateFunc	to
	)

state_add_transition Add a new transition into the machine

Parameters

machine	a pointer obtained with state_newmachine
from	the current machine state
value	the value return by from
to	the state run after from, NULL if the machine must exit

Returns

0 if no error, 1 if memory error, 2 if transition already in machine

Examples:

basic.c, and demo_menu.c.

void state_free

(

struct StateMachine *

p

)

state_free release resource of a machine allocated with state_newmachine

Parameters

p	a pointer returned by state_newmachine

Examples:

basic.c, and demo_menu.c.

struct StateMachine* state_newmachine

(

)

state_newmachine instanciate a new empty machine

Returns

NULL if error, a pointer that must be release with state_free

Examples:

basic.c, and demo_menu.c.

int state_start	(	struct StateMachine *	machine,
		StateFunc	start,
		void *	data
	)

state_start run a state machine

Parameters

machine	a pointer to the state machine
start	the first state that will be run
data	a pointer that will be passed to all states

Returns

the return value of the last state run

Examples:

basic.c, and demo_menu.c.