epics-base/src/cas/example/simple/exPV.cc

/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
*     National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
*     Operator of Los Alamos National Laboratory.
* EPICS BASE Versions 3.13.7
* and higher are distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution. 
\*************************************************************************/
//
// Example EPICS CA server
//
#include "exServer.h"
#include "gddApps.h"

//
// static data for exPV
//
char exPV::hasBeenInitialized = 0;
gddAppFuncTable<exPV> exPV::ft;
epicsTime exPV::currentTime;

//
// special gddDestructor guarantees same form of new and delete
//
class exFixedStringDestructor: public gddDestructor {
    virtual void run (void *);
};

//
// exPV::exPV()
//
exPV::exPV ( exServer & casIn, pvInfo & setup, 
            bool preCreateFlag, bool scanOnIn ) : 
    cas ( casIn ),
    timer ( cas.createTimer() ),
    info ( setup ),
    interest ( false ),
    preCreate ( preCreateFlag ),
    scanOn ( scanOnIn )
{
    //
    // no dataless PV allowed
    //
    assert (this->info.getElementCount()>=1u);

    //
    // start a very slow background scan 
    // (we will speed this up to the normal rate when
    // someone is watching the PV)
    //
    if ( this->scanOn && this->info.getScanPeriod () > 0.0 ) {
        this->timer.start ( *this, this->getScanPeriod() );
    }
}

//
// exPV::~exPV()
//
exPV::~exPV() 
{
    this->timer.destroy ();
    this->info.unlinkPV();
}

//
// exPV::destroy()
//
// this is replaced by a noop since we are 
// pre-creating most of the PVs during init in this simple server
//
void exPV::destroy()
{
    if ( ! this->preCreate ) {
        delete this;
    }
}

//
// exPV::update()
//
caStatus exPV::update ( const gdd & valueIn )
{
#   if DEBUG
        printf("Setting %s too:\n", this->info.getName().string());
        valueIn.dump();
#   endif

    caStatus status = this->updateValue ( valueIn );
    if ( status || ( ! this->pValue.valid() ) ) {
        return status;
    }

    //
    // post a value change event
    //
    caServer * pCAS = this->getCAS();
    if ( this->interest == true && pCAS != NULL ) {
        casEventMask select ( pCAS->valueEventMask() | pCAS->logEventMask() );
        this->postEvent ( select, valueIn );
    }

    return S_casApp_success;
}

//
// exScanTimer::expire ()
//
epicsTimerNotify::expireStatus
exPV::expire ( const epicsTime & /*currentTime*/ ) // X aCC 361
{
    this->scan();
    if ( this->scanOn && this->getScanPeriod() > 0.0 ) {
        return expireStatus ( restart, this->getScanPeriod() );
    }
    else {
        return noRestart;
    }
}

//
// exPV::bestExternalType()
//
aitEnum exPV::bestExternalType () const
{
    return this->info.getType ();
}

//
// exPV::interestRegister()
//
caStatus exPV::interestRegister ()
{
    if ( ! this->getCAS() ) {
        return S_casApp_success;
    }

    this->interest = true;
    if ( this->scanOn && this->getScanPeriod() > 0.0 && 
            this->getScanPeriod() < this->timer.getExpireDelay() ) {
        this->timer.start ( *this, this->getScanPeriod() );
    }

    return S_casApp_success;
}

//
// exPV::interestDelete()
//
void exPV::interestDelete()
{
    this->interest = false;
}

//
// exPV::show()
//
void exPV::show ( unsigned level ) const
{
    if (level>1u) {
        if ( this->pValue.valid () ) {
            printf ( "exPV: cond=%d\n", this->pValue->getStat () );
            printf ( "exPV: sevr=%d\n", this->pValue->getSevr () );
            printf ( "exPV: value=%f\n", static_cast < double > ( * this->pValue ) );
        }
        printf ( "exPV: interest=%d\n", this->interest );
        this->timer.show ( level - 1u );
    }
}

//
// exPV::initFT()
//
void exPV::initFT ()
{
    if ( exPV::hasBeenInitialized ) {
            return;
    }

    //
    // time stamp, status, and severity are extracted from the
    // GDD associated with the "value" application type.
    //
    exPV::ft.installReadFunc ("value", &exPV::getValue);
    exPV::ft.installReadFunc ("precision", &exPV::getPrecision);
    exPV::ft.installReadFunc ("graphicHigh", &exPV::getHighLimit);
    exPV::ft.installReadFunc ("graphicLow", &exPV::getLowLimit);
    exPV::ft.installReadFunc ("controlHigh", &exPV::getHighLimit);
    exPV::ft.installReadFunc ("controlLow", &exPV::getLowLimit);
    exPV::ft.installReadFunc ("alarmHigh", &exPV::getHighLimit);
    exPV::ft.installReadFunc ("alarmLow", &exPV::getLowLimit);
    exPV::ft.installReadFunc ("alarmHighWarning", &exPV::getHighLimit);
    exPV::ft.installReadFunc ("alarmLowWarning", &exPV::getLowLimit);
    exPV::ft.installReadFunc ("units", &exPV::getUnits);
    exPV::ft.installReadFunc ("enums", &exPV::getEnums);

    exPV::hasBeenInitialized = 1;
}

//
// exPV::getPrecision()
//
caStatus exPV::getPrecision ( gdd & prec )
{
    prec.put(4u);
    return S_cas_success;
}

//
// exPV::getHighLimit()
//
caStatus exPV::getHighLimit ( gdd & value )
{
    value.put(info.getHopr());
    return S_cas_success;
}

//
// exPV::getLowLimit()
//
caStatus exPV::getLowLimit ( gdd & value )
{
    value.put(info.getLopr());
    return S_cas_success;
}

//
// exPV::getUnits()
//
caStatus exPV::getUnits( gdd & units )
{
    aitString str("furlongs", aitStrRefConstImortal);
    units.put(str);
    return S_cas_success;
}

//
// exPV::getEnums()
//
// returns the eneumerated state strings
// for a discrete channel
//
// The PVs in this example are purely analog,
// and therefore this isnt appropriate in an
// analog context ...
//
caStatus exPV::getEnums ( gdd & enumsIn )
{
    if ( this->info.getType () == aitEnumEnum16 ) {
        static const unsigned nStr = 2;
        aitFixedString *str;
        exFixedStringDestructor *pDes;

        str = new aitFixedString[nStr];
        if (!str) {
            return S_casApp_noMemory;
        }

        pDes = new exFixedStringDestructor;
        if (!pDes) {
            delete [] str;
            return S_casApp_noMemory;
        }

        strncpy (str[0].fixed_string, "off", 
            sizeof(str[0].fixed_string));
        strncpy (str[1].fixed_string, "on", 
            sizeof(str[1].fixed_string));

        enumsIn.setDimension(1);
        enumsIn.setBound (0,0,nStr);
        enumsIn.putRef (str, pDes);

        return S_cas_success;
    }

    return S_cas_success;
}

//
// exPV::getValue()
//
caStatus exPV::getValue ( gdd & value )
{
    caStatus status;

    if ( this->pValue.valid () ) {
        gddStatus gdds;

        gdds = gddApplicationTypeTable::
            app_table.smartCopy ( &value, & (*this->pValue) );
        if (gdds) {
            status = S_cas_noConvert;   
        }
        else {
            status = S_cas_success;
        }
    }
    else {
        status = S_casApp_undefined;
    }
    return status;
}

//
// exPV::write()
// (synchronous default)
//
caStatus exPV::write ( const casCtx &, const gdd & valueIn )
{
    return this->update ( valueIn );
}
 
//
// exPV::read()
// (synchronous default)
//
caStatus exPV::read ( const casCtx &, gdd & protoIn )
{
    return this->ft.read ( *this, protoIn );
}

//
// exPV::createChannel()
//
// for access control - optional
//
casChannel *exPV::createChannel ( const casCtx &ctx,
        const char * const /* pUserName */, 
        const char * const /* pHostName */ )
{
    return new exChannel ( ctx );
}

//
// exFixedStringDestructor::run()
//
// special gddDestructor guarantees same form of new and delete
//
void exFixedStringDestructor::run ( void * pUntyped )
{
    aitFixedString *ps = (aitFixedString *) pUntyped;
    delete [] ps;
}