transform_view.hpp

来自「Boost provides free peer-reviewed portab」· HPP 代码 · 共 108 行

/*=============================================================================
    Copyright (c) 2001-2006 Joel de Guzman

    Distributed under the Boost Software License, Version 1.0. (See accompanying 
    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
==============================================================================*/
#if !defined(FUSION_TRANSFORM_VIEW_07162005_1037)
#define FUSION_TRANSFORM_VIEW_07162005_1037

#include <boost/static_assert.hpp>
#include <boost/fusion/support/detail/access.hpp>
#include <boost/fusion/support/is_view.hpp>
#include <boost/fusion/support/category_of.hpp>
#include <boost/fusion/view/transform_view/transform_view_iterator.hpp>
#include <boost/fusion/view/transform_view/transform_view_fwd.hpp>
#include <boost/fusion/view/transform_view/detail/begin_impl.hpp>
#include <boost/fusion/view/transform_view/detail/end_impl.hpp>
#include <boost/fusion/view/transform_view/detail/at_impl.hpp>
#include <boost/fusion/view/transform_view/detail/value_at_impl.hpp>
#include <boost/fusion/view/detail/strictest_traversal.hpp>
#include <boost/fusion/container/vector/vector10.hpp>
#include <boost/fusion/sequence/intrinsic/size.hpp>
#include <boost/fusion/support/sequence_base.hpp>
#include <boost/fusion/sequence/intrinsic/begin.hpp>
#include <boost/fusion/sequence/intrinsic/end.hpp>
#include <boost/fusion/sequence/intrinsic/size.hpp>
#include <boost/mpl/bool.hpp>

namespace boost { namespace fusion
{
    struct void_;
    struct transform_view_tag;
    struct transform_view2_tag;
    struct fusion_sequence_tag;

    // Binary Version
    template <typename Sequence1, typename Sequence2, typename F>
    struct transform_view : sequence_base<transform_view<Sequence1, Sequence2, F> >
    {
        BOOST_STATIC_ASSERT(result_of::size<Sequence1>::value == result_of::size<Sequence2>::value);
        typedef transform_view2_tag fusion_tag;
        typedef fusion_sequence_tag tag; // this gets picked up by MPL
        typedef mpl::true_ is_view;

        typedef typename traits::category_of<Sequence1>::type category1;
        typedef typename traits::category_of<Sequence2>::type category2;
        typedef typename detail::strictest_traversal<
            fusion::vector2<Sequence1, Sequence2> >::type category;
        typedef typename result_of::begin<Sequence1>::type first1_type;
        typedef typename result_of::begin<Sequence2>::type first2_type;
        typedef typename result_of::end<Sequence1>::type last1_type;
        typedef typename result_of::end<Sequence2>::type last2_type;
        typedef typename result_of::size<Sequence1>::type size;
        typedef Sequence1 sequence1_type;
        typedef Sequence2 sequence2_type;
        typedef F transform_type;

        transform_view(Sequence1& seq1, Sequence2& seq2, F const& binop)
            : f(binop)
            , seq1(seq1)
            , seq2(seq2)
        {}

        first1_type first1() const { return fusion::begin(seq1); }
        first2_type first2() const { return fusion::begin(seq2); }
        last1_type last1() const { return fusion::end(seq1); }
        last2_type last2() const { return fusion::end(seq2); }

        transform_type f;
        typename mpl::if_<traits::is_view<Sequence1>, Sequence1, Sequence1&>::type seq1;
        typename mpl::if_<traits::is_view<Sequence2>, Sequence2, Sequence2&>::type seq2;
    };

    // Unary Version
    template <typename Sequence, typename F>
#if defined(BOOST_NO_PARTIAL_SPECIALIZATION_IMPLICIT_DEFAULT_ARGS)
    struct transform_view<Sequence, F, void_> : sequence_base<transform_view<Sequence, F, void_> >
#else
    struct transform_view<Sequence, F> : sequence_base<transform_view<Sequence, F> >
#endif
    {
        typedef transform_view_tag fusion_tag;
        typedef fusion_sequence_tag tag; // this gets picked up by MPL
        typedef mpl::true_ is_view;

        typedef typename traits::category_of<Sequence>::type category;
        typedef typename result_of::begin<Sequence>::type first_type;
        typedef typename result_of::end<Sequence>::type last_type;
        typedef typename result_of::size<Sequence>::type size;
        typedef Sequence sequence_type;
        typedef F transform_type;

        transform_view(Sequence& seq, F const& f)
            : seq(seq)
            , f(f)
        {}

        first_type first() const { return fusion::begin(seq); }
        last_type last() const { return fusion::end(seq); }
        typename mpl::if_<traits::is_view<Sequence>, Sequence, Sequence&>::type seq;
        transform_type f;
    };
}}

#endif