QMsm Class Reference

QM state machine implementation strategy. More...

#include "qep.h"

Inheritance diagram for QMsm:

Public Member Functions
bool	QMsm_isInState (QMsm const *const me, QMState const *const state)
QMState const *	QMsm_stateObj (QHsm const *const me)
QMState const *	QMsm_childStateObj (QHsm const *const me, QMState const *const parent)
QStateHandler	QMsm_getStateHandler_ (QHsm *const me)
Public Member Functions inherited from QHsm
bool	QHsm_isIn (QHsm *const me, QStateHandler const state)
QStateHandler	QHsm_childState (QHsm *const me, QStateHandler const parent)

Public Attributes
QHsm	super

Protected Member Functions
void	QMsm_ctor (QMsm *const me, QStateHandler const initial)
Protected Member Functions inherited from QHsm
void	QHsm_ctor (QHsm *const me, QStateHandler const initial)
QState	QHsm_top (QHsm const *const me, QEvt const *const e)
void	QHsm_init_ (QHsm *const me, void const *const e, uint_fast8_t const qs_id)
void	QHsm_dispatch_ (QHsm *const me, QEvt const *const e, uint_fast8_t const qs_id)

Private Member Functions
void	QMsm_init_ (QHsm *const me, void const *const e, uint_fast8_t const qs_id)
void	QMsm_dispatch_ (QHsm *const me, QEvt const *const e, uint_fast8_t const qs_id)
QState	QMsm_execTatbl_ (QHsm *const me, QMTranActTable const *const tatbl, uint_fast8_t const qs_id)
void	QMsm_exitToTranSource_ (QHsm *const me, QMState const *const cs, QMState const *const ts, uint_fast8_t const qs_id)
QState	QMsm_enterHistory_ (QHsm *const me, QMState const *const hist, uint_fast8_t const qs_id)

Additional Inherited Members
Static Public Member Functions inherited from QHsm
static QStateHandler	QHsm_state (QHsm *const me)

Detailed Description

QMsm (QM State Machine) provides a more efficient state machine implementation strategy than QHsm, but requires the use of the QM modeling tool, but are the fastest and need the least run-time support (the smallest event-processor taking up the least code space).

Note

QMsm is not intended to be instantiated directly, but rather serves as the abstrace base class for derivation of state machines in the application code.

Traceability

• REQ-QP-02_21

Usage

The following example illustrates how to derive a state machine class from QMsm. Please note that the QMsm member super is defined as the first member of the derived struct.

typedef struct {
    QMsm super; /* inherits QMsm */
 
    double operand1;
    double operand2;
    char display[DISP_WIDTH + 1];
    uint8_t len;
    uint8_t opKey;
} Calc;

Definition at line 651 of file qep.h.

Member Function Documentation

QMsm_isInState()

bool QMsm_isInState	(	QMsm const *const	me,
		QMState const *const	state
	)

Tests if a given state is part of the current active state configuration in a MSM.

Tests if a state machine derived from QMsm is-in a given state.

Note

For a MSM, to "be-in" a state means also to "be-in" a superstate of of the state.

Parameters

[in]	me	current instance pointer (see oop)
[in]	state	pointer to the QMState object that corresponds to the tested state.

Returns

'true' if the MSM "is in" the state and 'false' otherwise

Definition at line 80 of file qep_msm.c.

QMsm_stateObj()

QMState const * QMsm_stateObj

(

QHsm const *const

me

)

Obtain the current active state from a MSM (read only)

Parameters

[in]

me

current instance pointer (see oop)

Returns

the current active state-object

Note

This function is used in QM for auto-generating code for state history

Definition at line 99 of file qep_msm.c.

QMsm_childStateObj()

QMState const * QMsm_childStateObj	(	QHsm const *const	me,
		QMState const *const	parent
	)

Obtain the current active child state of a given parent in QMsm

Finds the child state of the given parent, such that this child state is an ancestor of the currently active state. The main purpose of this function is to support shallow history transitions in state machines derived from QMsm.

Parameters

[in]	me	current instance pointer (see oop)
[in]	parent	pointer to the state-handler object

Returns

the child of a given parent state, which is an ancestor of the currently active state. For the corner case when the currently active state is the given parent state, function returns the parent state.

Postcondition qep_msm:890

• the child must be found

See also

QMsm_childStateObj()

Definition at line 105 of file qep_msm.c.

QMsm_ctor()

void QMsm_ctor ( QMsm *const  me, QStateHandler const  initial  )

protected

Constructor of QMsm

Performs the first step of QMsm initialization by assigning the initial pseudostate to the currently active state of the state machine.

Parameters

[in,out]	me	current instance pointer (see oop)
[in]	initial	the top-most initial transition for the MSM.

Note

Must be called only ONCE before QHSM_INIT().

QMsm inherits QHsm, so by the oop convention it should call the constructor of the superclass, i.e., QHsm_ctor(). However, this would pull in the QHsmVtable, which in turn will pull in the code for QHsm_init_() and QHsm_dispatch_() implemetations. To avoid this code size penalty, in case QHsm is not used in a given project, the QMsm_ctor() performs direct intitialization of the Vtable, which avoids pulling in the code for QMsm.

Usage

The following example illustrates how to invoke QMsm_ctor() in the "constructor" of a derived state machine:

void Calc_ctor(Calc * const me) {
    /* superclass' ctor */
    QMsm_ctor(&me->super, Q_STATE_CAST(&Calc_initial));
 
    me->operand1 = 0.0;
    me->operand2 = 0.0;
    me->len      = 0U;
    me->opKey    = 0U;
}

Definition at line 145 of file qep_msm.c.

QMsm_init_()

void QMsm_init_ ( QHsm *const  me, void const *const  e, uint_fast8_t const  qs_id  )

private

Implementation of the top-most initial tran. in QMsm.

Executes the top-most initial transition in a MSM.

Parameters

[in,out]	me	current instance pointer (see oop)
[in]	e	pointer to an extra parameter (might be NULL)
[in]	qs_id	QS-id of this state machine (for QS local filter)

Precondition qep_msm:200

• the virtual pointer must be initialized,
• the top-most initial transition must be initialized,
• the initial transition must not be taken yet.

Note

This function should be called only via the virtual table (see QHSM_INIT()) and should NOT be called directly in the applications.

Definition at line 163 of file qep_msm.c.

QMsm_dispatch_()

void QMsm_dispatch_ ( QHsm *const  me, QEvt const *const  e, uint_fast8_t const  qs_id  )

private

Implementation of dispatching events to a QMsm

Dispatches an event for processing to a meta state machine (MSM). The processing of an event represents one run-to-completion (RTC) step.

Parameters

[in,out]	me	current instance pointer (see oop)
[in]	e	pointer to the event to be dispatched to the MSM
[in]	qs_id	QS-id of this state machine (for QS local filter)

Precondition qep_msm:300

• current state must be initialized

Note

This function should be called only via the virtual table (see QHSM_DISPATCH()) and should NOT be called directly in the applications.

Definition at line 207 of file qep_msm.c.

QMsm_getStateHandler_()

QStateHandler QMsm_getStateHandler_

(

QHsm *const

me

)

Implementation of getting the state handler in a QMsm subclass

Definition at line 379 of file qep_msm.c.

QMsm_execTatbl_()

QState QMsm_execTatbl_ ( QHsm *const  me, QMTranActTable const *const  tatbl, uint_fast8_t const  qs_id  )

private

Execute transition-action table

Helper function to execute transition sequence in a transition-action table.

Parameters

[in,out]	me	current instance pointer (see oop)
[in]	tatbl	pointer to the transition-action table
[in]	qs_id	QS-id of this state machine (for QS local filter)

Returns

status of the last action from the transition-action table.

Note

This function is for internal use inside the QEP event processor and should not be called directly from the applications.

Precondition

the transition-action table pointer must not be NULL

Definition at line 386 of file qep_msm.c.

QMsm_exitToTranSource_()

void QMsm_exitToTranSource_ ( QHsm *const  me, QMState const *const  cs, QMState const *const  ts, uint_fast8_t const  qs_id  )

private

Exit the current state up to the explicit transition source

Static helper function to exit the current state configuration to the transition source, which in a hierarchical state machine might be a superstate of the current state.

Parameters

[in,out]	me	current instance pointer (see oop)
[in]	cs	pointer to the current state
[in]	ts	pointer to the transition source state
[in]	qs_id	QS-id of this state machine (for QS local filter)

Definition at line 459 of file qep_msm.c.

QMsm_enterHistory_()

QState QMsm_enterHistory_ ( QHsm *const  me, QMState const *const  hist, uint_fast8_t const  qs_id  )

private

Enter history of a composite state

Static helper function to execute the segment of transition to history after entering the composite state and

Parameters

[in,out]	me	current instance pointer (see oop)
[in]	hist	pointer to the history substate
[in]	qs_id	QS-id of this state machine (for QS local filter)

Returns

Q_RET_TRAN_INIT, if an initial transition has been executed in the last entered state or Q_RET_NULL if no such transition was taken.

Definition at line 495 of file qep_msm.c.

Member Data Documentation

super

QHsm QMsm::super

Definition at line 653 of file qep.h.

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The documentation for this class was generated from the following files:

• qep.h
• qep_msm.c