detail/overlay/copy_segments.hpp

// Boost.Geometry (aka GGL, Generic Geometry Library)

// Copyright (c) 2007-2014 Barend Gehrels, Amsterdam, the Netherlands.

// This file was modified by Oracle on 2014.
// Modifications copyright (c) 2014 Oracle and/or its affiliates.

// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle

// Use, modification and distribution is subject to 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)

#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_COPY_SEGMENTS_HPP
#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_COPY_SEGMENTS_HPP


#include <vector>

#include <boost/array.hpp>
#include <boost/mpl/assert.hpp>
#include <boost/range.hpp>
#include <boost/type_traits/integral_constant.hpp>

#include <boost/geometry/core/assert.hpp>
#include <boost/geometry/core/exterior_ring.hpp>
#include <boost/geometry/core/interior_rings.hpp>
#include <boost/geometry/core/ring_type.hpp>
#include <boost/geometry/core/tags.hpp>
#include <boost/geometry/algorithms/not_implemented.hpp>
#include <boost/geometry/geometries/concepts/check.hpp>
#include <boost/geometry/iterators/ever_circling_iterator.hpp>
#include <boost/geometry/views/closeable_view.hpp>
#include <boost/geometry/views/reversible_view.hpp>

#include <boost/geometry/algorithms/detail/overlay/append_no_duplicates.hpp>
#include <boost/geometry/algorithms/detail/overlay/append_no_dups_or_spikes.hpp>

#include <boost/geometry/util/range.hpp>


namespace boost { namespace geometry
{


#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace copy_segments
{


template <bool Reverse>
struct copy_segments_ring
{
    template
    <
        typename Ring,
        typename SegmentIdentifier,
        typename RobustPolicy,
        typename RangeOut
    >
    static inline void apply(Ring const& ring,
            SegmentIdentifier const& seg_id,
            signed_size_type to_index,
            RobustPolicy const& robust_policy,
            RangeOut& current_output)
    {
        typedef typename closeable_view
        <
            Ring const,
            closure<Ring>::value
        >::type cview_type;

        typedef typename reversible_view
        <
            cview_type const,
            Reverse ? iterate_reverse : iterate_forward
        >::type rview_type;

        typedef typename boost::range_iterator<rview_type const>::type iterator;
        typedef geometry::ever_circling_iterator<iterator> ec_iterator;


        cview_type cview(ring);
        rview_type view(cview);

        // The problem: sometimes we want to from "3" to "2"
        // -> end = "3" -> end == begin
        // This is not convenient with iterators.

        // So we use the ever-circling iterator and determine when to step out

        signed_size_type const from_index = seg_id.segment_index + 1;

        // Sanity check
        BOOST_GEOMETRY_ASSERT(from_index < static_cast<signed_size_type>(boost::size(view)));

        ec_iterator it(boost::begin(view), boost::end(view),
                    boost::begin(view) + from_index);

        // [2..4] -> 4 - 2 + 1 = 3 -> {2,3,4} -> OK
        // [4..2],size=6 -> 6 - 4 + 2 + 1 = 5 -> {4,5,0,1,2} -> OK
        // [1..1], travel the whole ring round
        signed_size_type const count = from_index <= to_index
            ? to_index - from_index + 1
            : static_cast<signed_size_type>(boost::size(view))
                - from_index + to_index + 1;

        for (signed_size_type i = 0; i < count; ++i, ++it)
        {
            detail::overlay::append_no_dups_or_spikes(current_output, *it, robust_policy);
        }
    }
};

template <bool Reverse, bool RemoveSpikes = true>
class copy_segments_linestring
{
private:
    // remove spikes
    template <typename RangeOut, typename Point, typename RobustPolicy>
    static inline void append_to_output(RangeOut& current_output,
                                        Point const& point,
                                        RobustPolicy const& robust_policy,
                                        boost::true_type const&)
    {
        detail::overlay::append_no_dups_or_spikes(current_output, point,
                                                  robust_policy);
    }

    // keep spikes
    template <typename RangeOut, typename Point, typename RobustPolicy>
    static inline void append_to_output(RangeOut& current_output,
                                        Point const& point,
                                        RobustPolicy const&,
                                        boost::false_type const&)
    {
        detail::overlay::append_no_duplicates(current_output, point);
    }

public:
    template
    <
        typename LineString,
        typename SegmentIdentifier,
        typename RobustPolicy,
        typename RangeOut
    >
    static inline void apply(LineString const& ls,
            SegmentIdentifier const& seg_id,
            signed_size_type to_index,
            RobustPolicy const& robust_policy,
            RangeOut& current_output)
    {
        signed_size_type const from_index = seg_id.segment_index + 1;

        // Sanity check
        if ( from_index > to_index
          || from_index < 0
          || to_index >= static_cast<signed_size_type>(boost::size(ls)) )
        {
            return;
        }

        signed_size_type const count = to_index - from_index + 1;

        typename boost::range_iterator<LineString const>::type
            it = boost::begin(ls) + from_index;

        for (signed_size_type i = 0; i < count; ++i, ++it)
        {
            append_to_output(current_output, *it, robust_policy,
                             boost::integral_constant<bool, RemoveSpikes>());
        }
    }
};

template <bool Reverse>
struct copy_segments_polygon
{
    template
    <
        typename Polygon,
        typename SegmentIdentifier,
        typename RobustPolicy,
        typename RangeOut
    >
    static inline void apply(Polygon const& polygon,
            SegmentIdentifier const& seg_id,
            signed_size_type to_index,
            RobustPolicy const& robust_policy,
            RangeOut& current_output)
    {
        // Call ring-version with the right ring
        copy_segments_ring<Reverse>::apply
            (
                seg_id.ring_index < 0
                    ? geometry::exterior_ring(polygon)
                    : range::at(geometry::interior_rings(polygon), seg_id.ring_index),
                seg_id, to_index,
                robust_policy,
                current_output
            );
    }
};


template <bool Reverse>
struct copy_segments_box
{
    template
    <
        typename Box,
        typename SegmentIdentifier,
        typename RobustPolicy,
        typename RangeOut
    >
    static inline void apply(Box const& box,
            SegmentIdentifier const& seg_id,
            signed_size_type to_index,
            RobustPolicy const& robust_policy,
            RangeOut& current_output)
    {
        signed_size_type index = seg_id.segment_index + 1;
        BOOST_GEOMETRY_ASSERT(index < 5);

        signed_size_type const count = index <= to_index
            ? to_index - index + 1
            : 5 - index + to_index + 1;

        // Create array of points, the fifth one closes it
        boost::array<typename point_type<Box>::type, 5> bp;
        assign_box_corners_oriented<Reverse>(box, bp);
        bp[4] = bp[0];

        // (possibly cyclic) copy to output
        //    (see comments in ring-version)
        for (signed_size_type i = 0; i < count; i++, index++)
        {
            detail::overlay::append_no_dups_or_spikes(current_output,
                bp[index % 5], robust_policy);

        }
    }
};


template<typename Policy>
struct copy_segments_multi
{
    template
    <
        typename MultiGeometry,
        typename SegmentIdentifier,
        typename RobustPolicy,
        typename RangeOut
    >
    static inline void apply(MultiGeometry const& multi_geometry,
            SegmentIdentifier const& seg_id,
            signed_size_type to_index,
            RobustPolicy const& robust_policy,
            RangeOut& current_output)
    {

        BOOST_GEOMETRY_ASSERT
            (
                seg_id.multi_index >= 0
                && static_cast<std::size_t>(seg_id.multi_index) < boost::size(multi_geometry)
            );

        // Call the single-version
        Policy::apply(range::at(multi_geometry, seg_id.multi_index),
                      seg_id, to_index,
                      robust_policy,
                      current_output);
    }
};


}} // namespace detail::copy_segments
#endif // DOXYGEN_NO_DETAIL


#ifndef DOXYGEN_NO_DISPATCH
namespace dispatch
{

template
<
    typename Tag,
    bool Reverse
>
struct copy_segments : not_implemented<Tag>
{};


template <bool Reverse>
struct copy_segments<ring_tag, Reverse>
    : detail::copy_segments::copy_segments_ring<Reverse>
{};


template <bool Reverse>
struct copy_segments<linestring_tag, Reverse>
    : detail::copy_segments::copy_segments_linestring<Reverse>
{};

template <bool Reverse>
struct copy_segments<polygon_tag, Reverse>
    : detail::copy_segments::copy_segments_polygon<Reverse>
{};


template <bool Reverse>
struct copy_segments<box_tag, Reverse>
    : detail::copy_segments::copy_segments_box<Reverse>
{};


template<bool Reverse>
struct copy_segments<multi_polygon_tag, Reverse>
    : detail::copy_segments::copy_segments_multi
        <
            detail::copy_segments::copy_segments_polygon<Reverse>
        >
{};


} // namespace dispatch
#endif // DOXYGEN_NO_DISPATCH


/*!
    \brief Copy segments from a geometry, starting with the specified segment (seg_id)
        until the specified index (to_index)
    \ingroup overlay
 */
template
<
    bool Reverse,
    typename Geometry,
    typename SegmentIdentifier,
    typename RobustPolicy,
    typename RangeOut
>
inline void copy_segments(Geometry const& geometry,
            SegmentIdentifier const& seg_id,
            signed_size_type to_index,
            RobustPolicy const& robust_policy,
            RangeOut& range_out)
{
    concept::check<Geometry const>();

    dispatch::copy_segments
        <
            typename tag<Geometry>::type,
            Reverse
        >::apply(geometry, seg_id, to_index, robust_policy, range_out);
}


}} // namespace boost::geometry


#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_COPY_SEGMENTS_HPP