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Allow jumping to arbitrary state in a SSM

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This is looking less and less like a simple state machine now, but it's
proving a useful model!
This commit is contained in:
Daniel Drake 2008-02-15 18:09:14 +00:00
parent 77b5dab04b
commit 0aaffcee33
2 changed files with 15 additions and 1 deletions
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15
libfprint/drv.c
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@ -297,6 +297,11 @@ void fpi_drvcb_identify_stopped(struct fp_dev *dev)
* There is also an implicit error state and an implicit accepting state * There is also an implicit error state and an implicit accepting state
* (both with implicit edges from every state). * (both with implicit edges from every state).
* *
* You can also jump to any arbitrary state (while marking completion of the
* current state) while the machine is running. In other words there are
* implicit edges linking one state to every other state. OK, we're stretching
* the "state machine" description at this point.
*
* To create a ssm, you pass a state handler function and the total number of * To create a ssm, you pass a state handler function and the total number of
* states (4 in the above example). * states (4 in the above example).
* *
@ -377,7 +382,7 @@ void fpi_ssm_mark_completed(struct fpi_ssm *machine)
/* Mark a ssm as aborted with error. */ /* Mark a ssm as aborted with error. */
void fpi_ssm_mark_aborted(struct fpi_ssm *machine, int error) void fpi_ssm_mark_aborted(struct fpi_ssm *machine, int error)
{ {
fp_dbg("error %d", error); fp_dbg("error %d from state %d", error, machine->cur_state);
BUG_ON(error == 0); BUG_ON(error == 0);
machine->error = error; machine->error = error;
fpi_ssm_mark_completed(machine); fpi_ssm_mark_completed(machine);
@ -395,3 +400,11 @@ void fpi_ssm_next_state(struct fpi_ssm *machine)
} }
} }
void fpi_ssm_jump_to_state(struct fpi_ssm *machine, int state)
{
BUG_ON(machine->completed);
BUG_ON(state >= machine->nr_states);
machine->cur_state = state;
__ssm_call_handler(machine);
}

1
libfprint/fp_internal.h
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@ -349,6 +349,7 @@ int fpi_ssm_has_completed(struct fpi_ssm *machine);
/* for drivers */ /* for drivers */
void fpi_ssm_next_state(struct fpi_ssm *machine); void fpi_ssm_next_state(struct fpi_ssm *machine);
void fpi_ssm_jump_to_state(struct fpi_ssm *machine, int state);
void fpi_ssm_mark_completed(struct fpi_ssm *machine); void fpi_ssm_mark_completed(struct fpi_ssm *machine);
void fpi_ssm_mark_aborted(struct fpi_ssm *machine, int error); void fpi_ssm_mark_aborted(struct fpi_ssm *machine, int error);