SEXP_downcast.hpp

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/*CXXR $Id: SEXP_downcast.hpp 1397 2013-08-16 18:25:59Z arr $
 *CXXR
 *CXXR This file is part of CXXR, a project to refactor the R interpreter
 *CXXR into C++.  It may consist in whole or in part of program code and
 *CXXR documentation taken from the R project itself, incorporated into
 *CXXR CXXR (and possibly MODIFIED) under the terms of the GNU General Public
 *CXXR Licence.
 *CXXR 
 *CXXR CXXR is Copyright (C) 2008-13 Andrew R. Runnalls, subject to such other
 *CXXR copyrights and copyright restrictions as may be stated below.
 *CXXR 
 *CXXR CXXR is not part of the R project, and bugs and other issues should
 *CXXR not be reported via r-bugs or other R project channels; instead refer
 *CXXR to the CXXR website.
 *CXXR */

/*
 *  R : A Computer Language for Statistical Data Analysis
 *
 *  This program 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 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, a copy is available at
 *  http://www.r-project.org/Licenses/
 */

#ifndef SEXP_DOWNCAST_HPP
#define SEXP_DOWNCAST_HPP 1

#include "CXXR/RObject.h"

namespace CXXR {
#ifdef __GNUC__
    __attribute__((noreturn))
#endif

    void SEXP_downcast_error(const char* given, const char* wanted);

#ifdef UNCHECKED_SEXP_DOWNCAST
    template <typename PtrOut, typename PtrIn>
    inline PtrOut SEXP_downcast(PtrIn s, bool allow_null = true)
    {
        if (!s && !allow_null) {
            PtrOut exemplar = 0;
            SEXP_downcast_error("NULL", exemplar->staticTypeName());
        }
        return static_cast<PtrOut>(s);
    }
#else
    template <typename PtrOut, typename PtrIn>
    PtrOut SEXP_downcast(PtrIn s, bool allow_null = true)
    {
        PtrOut ans = 0;
        if (!s) {
            if (allow_null)
                return 0;
            else SEXP_downcast_error("NULL", ans->staticTypeName());
        }
        ans = dynamic_cast<PtrOut>(s);
        if (!ans)
            SEXP_downcast_error(s->typeName(), ans->staticTypeName());
        return ans;
    }
#endif
}  // namespace CXXR

#endif  // SEXP_DOWNCAST_HPP