QEvt Class Reference

Event class. More...

#include "qp.h"

Inheritance diagram for QEvt:

Static Public Member Functions
static void	QEvt_ctor (QEvt *const me, enum_t const sig)
static QEvt *	QEvt_init (QEvt *const me, uint8_t dummy)
	Event without parameters initialization.

Public Attributes
QSignal	sig
	Signal of the event (see Event Signal)

Static Private Member Functions
static bool	QEvt_verify_ (QEvt const *const me)
	Internal function to verify the internal integrity of the event instance (QP FuSa Subsystem)
static uint_fast8_t	QEvt_getPoolNum_ (QEvt const *const me)
	Internal function to get the event pool-number of the given event.
static void	QEvt_refCtr_inc_ (QEvt const *me)
static void	QEvt_refCtr_dec_ (QEvt const *me)

Private Attributes
uint8_t	evtTag_
	Event "tag" contains pool-ID plus the Duplicate Inverted Storage of the QEvt::refCtr_.
uint8_t volatile	refCtr_
	Event reference counter.

Detailed Description

Event class.

Details

Class QEvt represents QP events and serves as the base class for derivation of events with parameters (see also Object Orientation). Please see the QEvt class design specifications linked in the "Backward Traceability" section.

Backward Traceability

• SDS_QP_QEP : QEP Event Processor
• SDS_QP_QEvt : QEvt event class.

Forward Traceability

• QEvt::sig : Signal of the event (see Event Signal)
• QEvt::refCtr_ : Event reference counter.
• QEvt::evtTag_ : Event "tag" contains pool-ID plus the Duplicate Inverted Storage of the QEvt::refCtr_
• QEvt::QEvt_init() : Event without parameters initialization

Usage

The following example illustrates how to add event parameter(s) by inheriting the QEvt class. Please note that the QEvt member super is defined as the FIRST member of the derived class:

typedef struct {
    QEvt super; // <=== inherit QEvt
    // event parameters follow...
    uint8_t keyId; // ID of the key pressed
} KeypressEvt;

The following examples illustrate recommended ways to instantiate event objects based on the RAII principle (Resource Acquisition Is Initialization). Please see also QEVT_INITIALIZER().

// immutable event without parameters
static QEvt const myEvt = QEVT_INITIALIZER(MY_SIG);
// post, publish, or dispatch the immutable event...
 
// immutable event with parameters
static KeypressEvt const keyEvt = {
    QEVT_INITIALIZER(KEYPRESS_SIG),
    .keyId = 12U
}
// post, publish, or dispatch the immutable event...
 
// mutable event without parameters (e.g., automatic object inside a function)
QEvt myEvt = QEVT_INITIALIZER(sig); // sig is a variable
// dispatch the event (asynchronous posting or publishing probably WRONG!)
 
// mutable event with parameters (e.g., automatic object inside a function)
KeypressEvt keyEvt = { // sig and keyId are variables
    QEVT_INITIALIZER(sig),
    .keyId = keyId
};
// dispatch the event (asynchronous posting or publishing probably WRONG!)

Note

Please see macros Q_NEW() or Q_NEW_X() for code examples of allocating dynamic mutable events.

Definition at line 131 of file qp.h.

Member Function Documentation

QEvt_ctor()

static void QEvt_ctor ( QEvt *const me, enum_t const sig )

inlinestatic

Definition at line 151 of file qp.h.

QEvt_init()

static QEvt * QEvt_init ( QEvt *const me, uint8_t dummy )

inlinestatic

Event without parameters initialization.

Details

The main purpose of the QEvt initialization is to support dynamic allocation of events without parameters with the macros Q_NEW() or Q_NEW_X().

Remarks

The QEvt_init() can be also used to initialize event instances (or the portion inherited from QEvt in events with parameters), but this is not recommended. Instead, the recommended ways of instantiating event objects use the RAII principle (Resource Acquisition Is Initialization) and are based on the QEVT_INITIALIZER() macro, as illustrated in the QEvt class.

Parameters

[in,out]	me	current instance pointer (see Object Orientation)
[in]	dummy	shall be set to QEVT_DYNAMIC for dynamic events

Returns

Pointer to the initialized event (the me pointer, see Object Orientation).

Backward Traceability

• SRS_QP_EVT_40 : QP/C Framework may be compile-time configurable to allow customized constructor and other custom operations on event instances
• QEvt : Event class

Usage

The following example illustrates the use of the QEvt_init() directly (not recommended because not based on RAII):

// mutable event without parameters (type QEvt)
QEvt myEvt; // <== event instance (e.g., on the stack)
QEvt_init(&myEvt, MY_SIG); // <== initialize the event (not recommended)
// dispatch the event (asynchronous posting or publishing probably WRONG!)
 
// mutable event with parameters (type KeypressEvt derived from QEvt)
KeypressEvt keypressEvt; // <== event instance (e.g., on the stack)
QEvt_init(&keypressEvt.super, KEYPRESS_SIG); // <== initialize the .super member
keypressEvt.keyId = 23U; // initialize the event parameter
// dispatch keypressEvt...

The following example illustrates the use of the QEvt_init() implicitly (called by the macro Q_NEW()) when the configuration macro QEVT_PAR_INIT is defined:

// variadic version of Q_NEW() (QEVT_DYNAMIC passed to QEvt_init())
QEvt const *pe = Q_NEW(QEvt, MY_SIG, QEVT_DYNAMIC);
// post or publish the event...

Definition at line 160 of file qp.h.

QEvt_verify_()

static bool QEvt_verify_ ( QEvt const *const me )

inlinestaticprivate

Internal function to verify the internal integrity of the event instance (QP FuSa Subsystem)

Description

The integrity checks include:

• range check of the reference counter
• Duplicate Inverse Storage check of bits reference counter bits 0:3

Parameters

[in]

me

current instance pointer (see Object Orientation)

Returns

'true' if this event passes the integrity check and 'false' otherwise.

Definition at line 171 of file qp.h.

QEvt_getPoolNum_()

static uint_fast8_t QEvt_getPoolNum_ ( QEvt const *const me )

inlinestaticprivate

Internal function to get the event pool-number of the given event.

Parameters

[in]

me

current instance pointer (see Object Orientation)

Returns

Pool-ID of the event. The Pool-ID is zero for immutable (static) events.

Definition at line 179 of file qp.h.

QEvt_refCtr_inc_()

static void QEvt_refCtr_inc_ ( QEvt const * me )

inlinestaticprivate

Internal function to increment the refCtr of a const event.

Details

This function requires "casting `const` away" from the event pointer, which violates MISRA-C:2023 Rule 11.8. This function encapsulates this violation.

Backward Traceability

• DVR_QP_MC4_R11_08

Definition at line 77 of file qp_pkg.h.

QEvt_refCtr_dec_()

static void QEvt_refCtr_dec_ ( QEvt const * me )

inlinestaticprivate

Internal function to decrement the refCtr of a const event.

Details

This function requires "casting `const` away" from the event pointer, which violates MISRA-C:2023 Rule 11.8. This function encapsulates this violation.

Backward Traceability

• DVR_QP_MC4_R11_08

Definition at line 86 of file qp_pkg.h.

Member Data Documentation

sig

QSignal sig

Signal of the event (see Event Signal)

Backward Traceability

• QEvt : Event class
• SRS_QP_EVT_20 : Each event instance shall contain the event Signal

Definition at line 135 of file qp.h.

evtTag_

uint8_t evtTag_

private

Event "tag" contains pool-ID plus the Duplicate Inverted Storage of the QEvt::refCtr_.

Details

The 8-bit evtTag_ member stores the event-pool number (in bits 4:7) and the Duplicate Inverted Storage of the QEvt::refCtr_ for integrity checking (in bits 0:3). For mutable events, the QEvt_ctor() initializes refCtr_ to 0 and consequently evtTag_ to 0xF. For immutable events (not from event pools) the QEVT_INITIALIZER() macro initializes refCtr_ to 0xE and consequently evtTag_ to 0x1.

Backward Traceability

• QEvt : Event class
• SRS_QP_EVT_31 : Event abstraction may contain other data items for internal event management inside QP/C Framework
• SRS_QP_EVT_30 : QP/C Framework shall allow Application to create event instances with Parameters defined by the Application

Definition at line 140 of file qp.h.

refCtr_

uint8_t volatile refCtr_

private

Event reference counter.

Details

For mutable events (events from event pools), the 8-bit member QEvt::refCtr_ holds the reference count, which must be in the rage 0..2*QF_MAX_ACTIVE. For immutable (static) events, the member QEvt::refCtr_ holds the fixed value 0xE, which is initialized in the macro QEVT_INITIALIZER().

Backward Traceability

• QEvt : Event class
• SRS_QP_EVT_31 : Event abstraction may contain other data items for internal event management inside QP/C Framework
• SRS_QP_EVT_30 : QP/C Framework shall allow Application to create event instances with Parameters defined by the Application

Definition at line 143 of file qp.h.

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

• qp.h
• qp_pkg.h
• qp.dox
• qp_pkg.dox