QP::QMsm Class Reference

Hierarchical State Machine class (QMsm-style state machine implementation strategy) More...

#include "qp.hpp"

Inheritance diagram for QP::QMsm:

Public Member Functions
void	init (void const *const e, std::uint_fast8_t const qsId) override
	Virtual function to take the top-most initial transition in the state machine.
void	init (std::uint_fast8_t const qsId) override
	Virtual function to take the top-most initial transition in the state machine (overloaded).
void	dispatch (QEvt const *const e, std::uint_fast8_t const qsId) override
	Virtual function to dispatch an event to the state machine.
QStateHandler	getStateHandler () noexcept override
bool	isIn (QStateHandler const state) noexcept override
QMState const *	childStateObj (QMState const *const parent) const noexcept
QMState const *	topQMState () const noexcept
Public Member Functions inherited from QP::QAsm
virtual	~QAsm () noexcept
	Virtual destructor of the QP::QAsm abstract base class.
QStateHandler	state () const noexcept
QMState const *	stateObj () const noexcept

Protected Member Functions
	QMsm (QStateHandler const initial) noexcept
Protected Member Functions inherited from QP::QAsm
	QAsm () noexcept
	Constructor of the QP::QAsm base class.
QState	tran (QStateHandler const target) noexcept
	Internal helper function to take a state transition in sublclasses of QP::QAsm.
QState	tran_hist (QStateHandler const hist) noexcept
	Internal helper function to take a state transition to history in sublclasses of QP::QAsm.
QState	super (QStateHandler const superstate) noexcept
	Internal helper function to indicate superstate of a given state in sublclasses of QP::QAsm.
QState	qm_tran (void const *const tatbl) noexcept
	Internal helper function to take a state transition in QP::QMsm.
QState	qm_tran_init (void const *const tatbl) noexcept
QState	qm_tran_hist (QMState const *const hist, void const *const tatbl) noexcept
	Internal helper function to take a state transition to history in QP::QMsm.
QState	qm_entry (QMState const *const s) noexcept
	Internal helper function to execute state entry actions in QP::QMsm.
QState	qm_exit (QMState const *const s) noexcept
	Internal helper function to execute state exit actions in QP::QMsm.

Private Member Functions
QState	execTatbl_ (QMTranActTable const *const tatbl, std::uint_fast8_t const qsId)
void	exitToTranSource_ (QMState const *const cs, QMState const *const ts, std::uint_fast8_t const qsId)
QState	enterHistory_ (QMState const *const hist, std::uint_fast8_t const qsId)

Additional Inherited Members
Public Types inherited from QP::QAsm
enum	QStateRet : QState {   Q_RET_SUPER , Q_RET_UNHANDLED , Q_RET_HANDLED , Q_RET_IGNORED ,   Q_RET_ENTRY , Q_RET_EXIT , Q_RET_NULL , Q_RET_TRAN ,   Q_RET_TRAN_INIT , Q_RET_TRAN_HIST }
enum	ReservedSig : QSignal { Q_EMPTY_SIG , Q_ENTRY_SIG , Q_EXIT_SIG , Q_INIT_SIG }
	Reserved signals by the QP-framework. More...
Static Public Member Functions inherited from QP::QAsm
static QState	top (void *const me, QEvt const *const e) noexcept
	Top state handler that ignores all events.
Protected Attributes inherited from QP::QAsm
QAsmAttr	m_state
	Current state (pointer to the current state-handler function)
QAsmAttr	m_temp
	Temporary storage for target/act-table etc.

Detailed Description

Hierarchical State Machine class (QMsm-style state machine implementation strategy)

Details

QP::QMsm (QM State Machine) provides a more efficient state machine implementation strategy than QP::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

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

Backward Traceability

• SRS_QP_SM_21 : QP/C++ Framework should provide a State Machine Implementation Strategy optimized for "automatic code generation"
• SDS_QP_QMsm : QMsm State machine class.

Usage

The following example illustrates how to derive a state machine class from QP::QMsm.

class ToasterOven : public QP::QMsm { // <== inherits QP::QMsm
public:
    ToasterOven();
 
public:
    // ctor
    ToasterOven() : QMsm(Q_STATE_CAST(&ToasterOven::initial)) {...}
 
protected:
    QM_STATE_DECL( initial);
    QM_STATE_DECL( doorClosed);
    QM_ACTION_DECL(doorClosed_e);
    QM_ACTION_DECL(doorClosed_x);
    QM_ACTION_DECL(doorClosed_i);
    . . .
}; // class ToastOven

Definition at line 391 of file qp.hpp.

Constructor & Destructor Documentation

QMsm()

QP::QMsm::QMsm ( QStateHandler const initial )

explicitprotectednoexcept

Constructor of QP::QMsm

Details

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

Parameters

[in]

initial

the top-most initial transition for the MSM.

Usage

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

void Calc::Calc()
  : QMsm(Q_STATE_CAST(&Calc::initial)); // <===
    . . .
{
    . . .
}

Definition at line 89 of file qep_msm.cpp.

Member Function Documentation

init() [1/2]

void QP::QMsm::init ( void const *const e, std::uint_fast8_t const qsId )

overridevirtual

Virtual function to take the top-most initial transition in the state machine.

Details

Synchronously executes the top-most initial transition in a state machine (must be overridden in the subclasses).

Parameters

[in]	e	pointer to an initialization parameter (might be nullptr)
[in]	qsId	QS-id of this state machine (for QS local filter)

Implements QP::QAsm.

Definition at line 97 of file qep_msm.cpp.

init() [2/2]

void QP::QMsm::init ( std::uint_fast8_t const qsId )

inlineoverridevirtual

Virtual function to take the top-most initial transition in the state machine (overloaded).

Details

Synchronously executes the top-most initial transition in a state machine. This overloaded version takes no initialization parameter.

Parameters

[in]

qsId

QS-id of this state machine (for QS local filter)

Reimplemented from QP::QAsm.

Definition at line 399 of file qp.hpp.

dispatch()

void QP::QMsm::dispatch ( QEvt const *const e, std::uint_fast8_t const qsId )

overridevirtual

Virtual function to dispatch an event to the state machine.

Details

Synchronously dispatches an event for processing to a state machine (must be overridden in the subclasses). The processing of an event represents one run-to-completion (RTC) step.

Parameters

[in]	e	pointer to the event to be dispatched to the MSM
[in]	qsId	QS-id of this state machine (for QS local filter)

Implements QP::QAsm.

Definition at line 158 of file qep_msm.cpp.

getStateHandler()

QStateHandler QP::QMsm::getStateHandler ( )

inlineoverridevirtualnoexcept

Implementation of getting the state handler in a QP::QMsm subclass

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

Returns

the current active state-handler

Note

This function is used for state history (deep history) in the auto-generated code by the QM modeling tool. Reimplemented from QP::QAsm.

Reimplemented from QP::QAsm.

Definition at line 407 of file qp.hpp.

isIn()

bool QP::QMsm::isIn ( QP::QStateHandler const state )

overridevirtualnoexcept

Details

Check if a given state is part of the current active state configuration in QMsm subclasses. Please note that in a hierarchical state machine, to "be in a state" means also to be in a superstate of of the state.

See also

QP::QAsm::isIn()

Attention

This function must be called only on a state machine that is in the "stable state configuration". Among others, this means that the state machine cannot call it in the middle of its own transition. Also, this function does NOT work when the state machine is directly or indirectly in a submachine state.

Precondition qep_hsm:602

• internal integrity check (Software Self-Monitoring (SSM))

Backward Traceability

• SRS_QP_SM_25

Reimplemented from QP::QAsm.

Definition at line 328 of file qep_msm.cpp.

childStateObj()

QMState const * QP::QMsm::childStateObj ( QMState const *const parent ) const

noexcept

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

Details

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]

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

Note

This function is used in the QM modeling tool for auto-generating code for state history (shallow history)

Definition at line 352 of file qep_msm.cpp.

execTatbl_()

QState QP::QMsm::execTatbl_ ( QMTranActTable const *const tatbl, std::uint_fast8_t const qsId )

private

Execute transition-action table

Details

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

Parameters

[in]	tatbl	pointer to the transition-action table
[in]	qsId	QS-id of this state machine (for QS local filter)

Returns

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

Precondition qep_msm:400

• provided state table cannot be NULL

Note

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

Definition at line 403 of file qep_msm.cpp.

exitToTranSource_()

void QP::QMsm::exitToTranSource_ ( QMState const *const cs, QMState const *const ts, std::uint_fast8_t const qsId )

private

Exit the current state up to the explicit transition source

Details

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]	cs	pointer to the current state
[in]	ts	pointer to the transition source state
[in]	qsId	QS-id of this state machine (for QS local filter)

Definition at line 466 of file qep_msm.cpp.

enterHistory_()

QState QP::QMsm::enterHistory_ ( QMState const *const hist, std::uint_fast8_t const qsId )

private

Enter history of a composite state

Details

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

Parameters

[in]	hist	pointer to the history substate
[in]	qsId	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 504 of file qep_msm.cpp.

topQMState()

QMState const * QP::QMsm::topQMState ( ) const

noexcept

Definition at line 567 of file qep_msm.cpp.

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

• qp.hpp
• qep_msm.cpp
• qp.dox