map.h

// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; eval: (progn (c-set-style "stroustrup") (c-set-offset 'innamespace 0)); -*-
// vi:set ts=4 sts=4 sw=4 noet :
// Copyright 2011, 2012, The TPIE development team
// 
// This file is part of TPIE.
// 
// TPIE is free software: you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the
// Free Software Foundation, either version 3 of the License, or (at your
// option) any later version.
// 
// TPIE 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 Lesser General Public License
// along with TPIE.  If not, see <http://www.gnu.org/licenses/>

#ifndef __TPIE_PIPELINING_MAP_H__
#define __TPIE_PIPELINING_MAP_H__

#include <tpie/pipelining/node.h>
#include <tpie/pipelining/pipe_base.h>
#include <tpie/pipelining/factory_helpers.h>
#include <tpie/pipelining/node_name.h>
#include <type_traits>

namespace tpie {
namespace pipelining {
namespace bits {

template <typename T>
struct unary_traits_imp;

template <typename C, typename R, typename A>
struct unary_traits_imp<R(C::*)(A)> {
    typedef A argument_type;
    typedef R return_type;
};

template <typename C, typename R, typename A>
struct unary_traits_imp<R(C::*)(A) const > {
    typedef A argument_type;
    typedef R return_type;
};

template <typename R, typename A>
struct unary_traits_imp<R(*)(A)> {
    typedef A argument_type;
    typedef R return_type;
};

template <typename T>
struct unary_traits: public unary_traits_imp<decltype(&T::operator()) > {};

template <typename F>
class map_t {
public:
    template <typename dest_t>
    class type: public node {
    private:
        F functor;
        dest_t dest;
    public:
        typedef typename std::decay<typename unary_traits<F>::argument_type>::type item_type;

        type(dest_t dest, const F & functor):
            functor(functor), dest(std::move(dest)) {
            set_name(bits::extract_pipe_name(typeid(F).name()), PRIORITY_NO_NAME);
        }
        
        void push(const item_type & item) {
            dest.push(functor(item));
        }
    };
};

template <typename F>
class map_temp_t {
public:
    template <typename dest_t>
    class type: public node {
    private:
        F functor;
        dest_t dest;
    public:
        type(dest_t dest, const F & functor):
            functor(functor), dest(std::move(dest)) {
            set_name(bits::extract_pipe_name(typeid(F).name()), PRIORITY_NO_NAME);
        }

        template <typename T>
        void push(const T & item) {
            dest.push(functor(item));
        }
    };
};


template <typename F>
class map_sink_t: public node {
private:
    F functor;
public:
    typedef typename std::decay<typename unary_traits<F>::argument_type>::type item_type;

    map_sink_t(const F & functor):
        functor(functor) {
        set_name(bits::extract_pipe_name(typeid(F).name()), PRIORITY_NO_NAME);
    }
    
    void push(const item_type & item) {
        functor(item);
    }
};

template <typename T>
struct has_argument_type {
    typedef char yes[1];
    typedef char no[2];

    // This does not seem to work as well as it should
    // template <typename C>
    // static yes& test(typename unary_traits_imp<decltype(&C::operator())>::argument_type *);

    template <typename C>
    static yes& test(decltype(&C::operator()) *);

    template <typename>
    static no& test(...);
    static const bool value = sizeof(test<T>(nullptr)) == sizeof(yes);
};

} //namespace bits

template <typename F, typename = typename std::enable_if<bits::has_argument_type<F>::value>::type>
pipe_middle<tempfactory<bits::map_t<F>, F> > map(const F & functor) {
    return tempfactory<bits::map_t<F>, F >(functor);
}

template <typename F, typename = typename std::enable_if<!bits::has_argument_type<F>::value>::type>
pipe_middle<tempfactory<bits::map_temp_t<F>, F> > map(const F & functor) {
    return tempfactory<bits::map_temp_t<F>, F >(functor);
}

template <typename F>
pipe_end<termfactory<bits::map_sink_t<F>, F> > map_sink(const F & functor) {
    return termfactory<bits::map_sink_t<F>, F >(functor);
}

} //namespace pipelining
} //namespace terrastream

#endif //__TPIE_PIPELINING_MAP_H__