secondo/Algebras/DRel/comparedisttype.cpp

/*
----
This file is part of SECONDO.

Copyright (C) 2015,
Faculty of Mathematics and Computer Science,
Database Systems for New Applications.

SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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(at your option) any later version.

SECONDO is distributed in the hope that it will be useful,
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
----


//[$][\$]



1 Implementation of the secondo operator compareDistType

*/
#include "DRel.h"
#include "NestedList.h"
#include "ListUtils.h"
#include "QueryProcessor.h"
#include "StandardTypes.h"

#include "DRelHelpers.h"

extern NestedList* nl;
extern QueryProcessor* qp;

namespace drel {

/*
1.1 Type Mapping

Expect a DRel or DFRel and another DRel or DFRel.

*/
    ListExpr compareDistTypeTM( ListExpr args ) {

        std::string err = "drel, drel expected";

        if( ! nl->HasLength( args, 2 ) ) {
            return listutils::typeError( err + 
                ": two arguments are expected" );
        }

        if( !DFRel::checkType( nl->First( args ) )
         && !DRel::checkType( nl->First( args ) ) ) {
            return listutils::typeError( err +
                ": first argument is not a drel" );
        }
        
        if( !DFRel::checkType( nl->Second( args ) )
         && !DRel::checkType( nl->Second( args ) ) ) {
            return listutils::typeError( err +
                ": second argument is not a drel" );
        }

        return listutils::basicSymbol<CcBool>( );
    }

/*
1.2 Value Mapping

Compares the disttypes of two drels. Return true, if the drels have the 
same disttype.

*/
    template<class T, class R>
    int compareDistTypeVMT( Word* args, Word& result, int message,
        Word& local, Supplier s ) {

        T* drelA = ( T* )args[ 0 ].addr;
        R* drelB = ( R* )args[ 1 ].addr;
        bool equal = drelA->template equalDistType<R>( drelB );

        result = qp->ResultStorage( s );
        CcBool* res = ( CcBool* ) result.addr;
        res->Set( true, equal );

        return 0;
    }

/*
1.3 ValueMapping Array of drfdistribute

*/
    ValueMapping compareDistTypeVM[ ] = {
        compareDistTypeVMT<DRel, DRel>,
        compareDistTypeVMT<DRel, DFRel>,
        compareDistTypeVMT<DFRel, DRel>,
        compareDistTypeVMT<DFRel, DFRel>
    };

/*
1.4 Selection function

*/
    int compareDistTypeSelect( ListExpr args ) {

        int n1 = nl->SymbolValue( nl->First( nl->First( args ) ) ) == 
            DRel::BasicType( ) ? 0 : 2;
        int n2 = nl->SymbolValue( nl->First( nl->Second( args ) ) ) == 
            DRel::BasicType( ) ? 0 : 1;
        
        return n1 + n2;
    }

/*
1.5 Specification of comparedisttype

*/
    OperatorSpec compareDistTypeSpec(
        " drel(X) x drel(X) "
        "-> bool ",
        " _ _ comparedisttype",
        "Compares to drels and return true, if the disttype are "
        "equal. ",
        " query drel1 drel2 comparedisttype"
    );

/*
1.6 Operator instance of comparedisttype operator

*/
    Operator compareDistTypeOp(
        "comparedisttype",
        compareDistTypeSpec.getStr( ),
        4,
        compareDistTypeVM,
        compareDistTypeSelect,
        compareDistTypeTM
    );

} // end of namespace drel