qep_msm.c File Reference

QMsm implementation More...

#include "qep_port.h"
#include "qassert.h"
#include "qs_port.h"

Include dependency graph for qep_msm.c:

Go to the source code of this file.

Macros
#define	QEP_ACT_PTR_INC_(act_)   (++(act_))
	Internal QEP macro to increment the given action table act_. More...

Enumerations
enum	{ QMSM_MAX_ENTRY_DEPTH_ = 4 }
	internal QEP constants More...

Functions
static QState	QMsm_execTatbl_ (QMsm *const me, QMTranActTable const *tatbl)
	helper function to execute a transition-action table. More...
static void	QMsm_exitToTranSource_ (QMsm *const me, QMState const *s, QMState const *ts)
	helper function to exit the current state up to the transition source More...
static QState	QMsm_enterHistory_ (QMsm *const me, QMState const *const hist)
	helper function to execute a transition to history More...
void	QMsm_ctor (QMsm *const me, QStateHandler initial)
	Protected "constructor" of QMsm. More...
void	QMsm_init_ (QMsm *const me, void const *par)
	Implementation of the top-most initial transition in QMsm. More...
void	QMsm_dispatch_ (QMsm *const me, QEvt const *const e)
	Implementation of disparching events to QMsm. More...
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. More...
const QMState *	QMsm_childStateObj_ (QMsm const *const me, QMState const *const parent)
	Helper function to obtain the current active child state of a parent. More...

Variables
static const QMState	l_msm_top_s

Detailed Description

QMsm implementation

Definition in file qep_msm.c.

Macro Definition Documentation

QEP_ACT_PTR_INC_

#define QEP_ACT_PTR_INC_

(

act_

)

(++(act_))

Internal QEP macro to increment the given action table act_.

Note

Incrementing a pointer violates the MISRA-C 2004 Rule 17.4(req), pointer arithmetic other than array indexing. Encapsulating this violation in a macro allows to selectively suppress this specific deviation.

Definition at line 73 of file qep_msm.c.

Enumeration Type Documentation

anonymous enum

anonymous enum

internal QEP constants

Enumerator
QMSM_MAX_ENTRY_DEPTH_	maximum depth of entry levels in a MSM for transition to history.

Definition at line 53 of file qep_msm.c.

Function Documentation

QMsm_execTatbl_()

static QState QMsm_execTatbl_ ( QMsm *const  me, QMTranActTable const *  tatbl  )

static

helper function to execute a transition-action table.

Description

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

Parameters

[in,out]	me	pointer (see Object Orientation)
[in]	tatbl	pointer to the transition-action table

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 364 of file qep_msm.c.

QMsm_exitToTranSource_()

static void QMsm_exitToTranSource_ ( QMsm *const  me, QMState const *  s, QMState const *  ts  )

static

helper function to exit the current state up to the transition source

Description

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	pointer (see Object Orientation)
[in]	s	pointer to the current state
[in]	ts	pointer to the transition source state

Definition at line 436 of file qep_msm.c.

QMsm_enterHistory_()

static QState QMsm_enterHistory_ ( QMsm *const  me, QMState const *const  hist  )

static

helper function to execute a transition to history

Description

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

Parameters

[in,out]	me	pointer (see Object Orientation)
[in]	hist	pointer to the history substate

Returns

#Q_RET_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 475 of file qep_msm.c.

QMsm_ctor()

void QMsm_ctor	(	QMsm *const	me,
		QStateHandler	initial
	)

Protected "constructor" of QMsm.

Description

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	pointer (see Object Orientation)
[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 Object Orientation 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 111 of file qep_msm.c.

QMsm_init_()

void QMsm_init_	(	QMsm *const	me,
		void const *	par
	)

Implementation of the top-most initial transition in QMsm.

Description

Executes the top-most initial transition in a MSM.

Parameters

[in,out]	me	pointer (see Object Orientation)
[in]	par	pointer to an extra parameter (might be NULL)

Note

Must be called only ONCE after the QMsm_ctor().

Precondition

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

Definition at line 133 of file qep_msm.c.

QMsm_dispatch_()

void QMsm_dispatch_	(	QMsm *const	me,
		QEvt const *const	e
	)

Implementation of disparching events to QMsm.

Description

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	pointer (see Object Orientation)
[in]	e	pointer to the event to be dispatched to the MSM

Note

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

Precondition

current state must be initialized

Definition at line 184 of file qep_msm.c.

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.

Description

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	pointer (see Object Orientation)
[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 539 of file qep_msm.c.

QMsm_childStateObj_()

const QMState* QMsm_childStateObj_	(	QMsm const *const	me,
		QMState const *const	parent
	)

Helper function to obtain the current active child state of a parent.

Description

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	pointer (see Object Orientation)
[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.

See also

QMsm_childStateObj()

Postcondition

the child must be found

Definition at line 570 of file qep_msm.c.

Variable Documentation

l_msm_top_s

const QMState l_msm_top_s

static

Initial value:

= {
    (QMState const *)0,
    Q_STATE_CAST(0),
    Q_ACTION_CAST(0),
    Q_ACTION_CAST(0),
 
}

Definition at line 58 of file qep_msm.c.