UnaryFunction.hpp

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/*CXXR $Id: UnaryFunction.hpp 1351 2013-03-08 15:12:28Z 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 UNARYFUNCTION_HPP
#define UNARYFUNCTION_HPP 1

#include <algorithm>
#include <boost/lambda/bind.hpp>
#include <boost/lambda/lambda.hpp>
#include "CXXR/VectorBase.h"
#include "CXXR/errors.h"

namespace CXXR {
    namespace VectorOps {
        struct CopyAllAttributes {
            static void copyAttributes(VectorBase* to, const VectorBase* from)
            {
                to->copyAttributes(from, true);
            }
        };
        struct CopyLayoutAttributes {
            static void copyAttributes(VectorBase* to, const VectorBase* from);
        };


        struct CopyNoAttributes {
            static void copyAttributes(VectorBase*, const VectorBase*)
            {}
        };

        template <typename argument_type,
                  typename result_type,
                  typename Functor>
        class UnaryNAPropagator
            : public std::unary_function<argument_type, result_type> {
        public:
            UnaryNAPropagator(const Functor& f)
                : m_func(f)
            {}
                
            result_type operator()(const argument_type& in) const
            {
                return (isNA(in)
                        ? NA<result_type>() 
                        : result_type((m_func)(ElementTraits::data(in))));
            }

            void warnings()
            {}
        private:
            Functor m_func;
        };

        template <class Functor>
        class NullUnaryFunctorWrapper
            : public std::unary_function<typename Functor::argument_type,
                                         typename Functor::result_type> {
        public:
            // See para. 3 of ISO14882:2003 Sec. 14.6.2 for why these
            // typedefs aren't inherited from std::unary_function:
            typedef typename Functor::argument_type argument_type;
            typedef typename Functor::result_type result_type;

            NullUnaryFunctorWrapper(const Functor& f)
                : m_func(f)
            {}
                
            result_type operator()(const argument_type& in) const
            {
                return (m_func)(in);
            }

            void warnings()
            {}
        private:
            Functor m_func;
        };

        template <typename Functor, class AttributeCopier,
                  template <typename, typename, typename> class FunctorWrapper
                  = UnaryNAPropagator>
        class UnaryFunction {
        public:
            UnaryFunction(const Functor& f = Functor())
                : m_f(f)
            {}

            template <class Vout, class Vin>
            Vout* apply(const Vin* v) const;
        private:
            Functor m_f;
        };

        template <class AttributeCopier,
                  template <typename,
                            typename, typename> class FunctorWrapper,
                  typename Functor>
        static UnaryFunction<Functor, AttributeCopier, FunctorWrapper>
        makeUnaryFunction(Functor f)
        {
            return UnaryFunction<AttributeCopier, Functor, FunctorWrapper>(f);
        }

        template <class AttributeCopier, typename Functor>
        static UnaryFunction<Functor, AttributeCopier>
        makeUnaryFunction(Functor f)
        {
            return UnaryFunction<Functor, AttributeCopier>(f);
        }
    }  // namespace VectorOps
}  // namespace CXXR


// ***** Implementations of non-inlined templated functions. *****

template <typename Functor, class AttributeCopier, 
          template <typename, typename, typename> class FunctorWrapper>
template <class Vout, class Vin>
Vout* CXXR::VectorOps::UnaryFunction<Functor,
                                     AttributeCopier,
                                     FunctorWrapper>::apply(const Vin* v) const
{
    using namespace boost::lambda;
    typedef typename Vin::value_type Inelt;
    typedef typename Vout::value_type Outelt;
    GCStackRoot<Vout> ans(CXXR_NEW(Vout(v->size())));
    FunctorWrapper<Inelt, Outelt, Functor> fwrapper(m_f);
    std::transform(v->begin(), v->end(), ans->begin(),
                   bind<Outelt>(var(fwrapper), _1));
    fwrapper.warnings();
    AttributeCopier::copyAttributes(ans, v);
    return ans;
}

#endif  // UNARYFUNCTION_HPP