S4.cpp

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// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-
//
// S4.cpp: Rcpp R/C++ interface class library -- S4 objects
//
// Copyright (C) 2010 - 2011 Dirk Eddelbuettel and Romain Francois
//
// This file is part of Rcpp.
//
// Rcpp is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// Rcpp is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// 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 Rcpp.  If not, see <http://www.gnu.org/licenses/>.

#include <Rcpp/S4.h>
#include <Rcpp/exceptions.h>
#include <Rcpp/Vector.h>

namespace Rcpp {

    S4::S4() : RObject(){}
        
    S4::S4(SEXP x) : RObject(){
        set( x) ;
    }
        
    S4::S4( const S4& other) : RObject(){
        setSEXP( other.asSexp() ) ;     
    }
        
    S4::S4( const RObject::SlotProxy& proxy ) : RObject() {
        set( proxy ) ;
    }
    S4::S4( const RObject::AttributeProxy& proxy ) : RObject() {
        set( proxy ) ;
    }
        
    S4& S4::operator=( const S4& other){
        setSEXP( other.asSexp() ) ;
        return *this ;
    }
        
    S4& S4::operator=( SEXP other ) {
        set( other ) ;
        return *this ;
    }
        
    S4::S4( const std::string& klass ) {
        SEXP oo = PROTECT( R_do_new_object(R_do_MAKE_CLASS(klass.c_str())) ) ;
        if (!Rf_inherits(oo, klass.c_str())) {
            UNPROTECT( 1) ;
            throw S4_creation_error( klass ) ;
        }
        setSEXP( oo ) ;
        UNPROTECT( 1) ; /* oo */
    }
        
    bool S4::is( const std::string& clazz ) {
        CharacterVector cl = attr("class");
                
        // simple test for exact match
        if( ! clazz.compare( cl[0] ) ) return true ;
                
        try{
            SEXP containsSym = ::Rf_install("contains");
            CharacterVector res(::Rf_getAttrib(
                                    ::R_do_slot(::R_getClassDef(CHAR(::Rf_asChar(as<SEXP>(cl)))),
                                                containsSym),
                                    R_NamesSymbol));

            // 
            // mimic the R call: 
            // names( slot( getClassDef( cl ), "contains" ) )
            // 
            // SEXP slotSym = Rf_install( "slot" ), // cannot cause gc() once in symbol table
            //     getClassDefSym = Rf_install( "getClassDef" );
            // CharacterVector res = internal::try_catch(Rf_lang2(R_NamesSymbol,
            //                                                    Rf_lang3(slotSym,
            //                                                             Rf_lang2( getClassDefSym, cl ), 
            //                                                             Rf_mkString( "contains" )))) ;
            return any( res.begin(), res.end(), clazz.c_str() ) ;
        } catch( ... ){
            // we catch eval_error and also not_compatible when 
            // contains is NULL
        }
        return false ;
                
    }
        
    void S4::set( SEXP x) {
        if( ! ::Rf_isS4(x) ){
            throw not_s4() ;
        } else{
            setSEXP( x) ;
        }
    }
        
} // namespace Rcpp