ceph/src/boost/boost/geometry/algorithms/detail/overlay/append_no_dups_or_spikes.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
   4
   5 // This file was modified by Oracle on 2014, 2017.
   6 // Modifications copyright (c) 2014-2017 Oracle and/or its affiliates.
   7
   8 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
   9
  10 // Use, modification and distribution is subject to the Boost Software License,
  11 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  12 // http://www.boost.org/LICENSE_1_0.txt)
  13
  14 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_APPEND_NO_DUPS_OR_SPIKES_HPP
  15 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_APPEND_NO_DUPS_OR_SPIKES_HPP
  16
  17 #include <boost/range.hpp>
  18
  19 #include <boost/geometry/algorithms/append.hpp>
  20 #include <boost/geometry/algorithms/detail/point_is_spike_or_equal.hpp>
  21 #include <boost/geometry/algorithms/detail/equals/point_point.hpp>
  22
  23 #include <boost/geometry/util/condition.hpp>
  24 #include <boost/geometry/util/range.hpp>
  25
  26
  27 namespace boost { namespace geometry
  28 {
  29
  30
  31 #ifndef DOXYGEN_NO_DETAIL
  32 namespace detail { namespace overlay
  33 {
  34
  35 // TODO: move this / rename this
  36 template <typename Point1, typename Point2, typename RobustPolicy>
  37 inline bool points_equal_or_close(Point1 const& point1,
  38         Point2 const& point2,
  39         RobustPolicy const& robust_policy)
  40 {
  41     if (detail::equals::equals_point_point(point1, point2))
  42     {
  43         return true;
  44     }
  45
  46     if (BOOST_GEOMETRY_CONDITION(! RobustPolicy::enabled))
  47     {
  48         return false;
  49     }
  50
  51     // Try using specified robust policy
  52     typedef typename geometry::robust_point_type
  53     <
  54         Point1,
  55         RobustPolicy
  56     >::type robust_point_type;
  57
  58     robust_point_type point1_rob, point2_rob;
  59     geometry::recalculate(point1_rob, point1, robust_policy);
  60     geometry::recalculate(point2_rob, point2, robust_policy);
  61
  62     return detail::equals::equals_point_point(point1_rob, point2_rob);
  63 }
  64
  65
  66 template <typename Range, typename Point, typename SideStrategy, typename RobustPolicy>
  67 inline void append_no_dups_or_spikes(Range& range, Point const& point,
  68         SideStrategy const& strategy,
  69         RobustPolicy const& robust_policy)
  70 {
  71 #ifdef BOOST_GEOMETRY_DEBUG_INTERSECTION
  72     std::cout << "  add: ("
  73         << geometry::get<0>(point) << ", " << geometry::get<1>(point) << ")"
  74         << std::endl;
  75 #endif
  76     // The code below this condition checks all spikes/dups
  77     // for geometries >= 3 points.
  78     // So we have to check the first potential duplicate differently
  79     if (boost::size(range) == 1
  80         && points_equal_or_close(*(boost::begin(range)), point, robust_policy))
  81     {
  82         return;
  83     }
  84
  85     traits::push_back<Range>::apply(range, point);
  86
  87     // If a point is equal, or forming a spike, remove the pen-ultimate point
  88     // because this one caused the spike.
  89     // If so, the now-new-pen-ultimate point can again cause a spike
  90     // (possibly at a corner). So keep doing this.
  91     // Besides spikes it will also avoid adding duplicates.
  92     while(boost::size(range) >= 3
  93             && point_is_spike_or_equal(point,
  94                 *(boost::end(range) - 3),
  95                 *(boost::end(range) - 2),
  96                 strategy,
  97                 robust_policy))
  98     {
  99         // Use the Concept/traits, so resize and append again
 100         traits::resize<Range>::apply(range, boost::size(range) - 2);
 101         traits::push_back<Range>::apply(range, point);
 102     }
 103 }
 104
 105 template <typename Range, typename SideStrategy, typename RobustPolicy>
 106 inline void clean_closing_dups_and_spikes(Range& range,
 107                 SideStrategy const& strategy,
 108                 RobustPolicy const& robust_policy)
 109 {
 110     std::size_t const minsize
 111         = core_detail::closure::minimum_ring_size
 112             <
 113                 geometry::closure<Range>::value
 114             >::value;
 115
 116     if (boost::size(range) <= minsize)
 117     {
 118         return;
 119     }
 120
 121     typedef typename boost::range_iterator<Range>::type iterator_type;
 122     static bool const closed = geometry::closure<Range>::value == geometry::closed;
 123
 124 // TODO: the following algorithm could be rewritten to first look for spikes
 125 // and then erase some number of points from the beginning of the Range
 126
 127     bool found = false;
 128     do
 129     {
 130         found = false;
 131         iterator_type first = boost::begin(range);
 132         iterator_type second = first + 1;
 133         iterator_type ultimate = boost::end(range) - 1;
 134         if (BOOST_GEOMETRY_CONDITION(closed))
 135         {
 136             ultimate--;
 137         }
 138
 139         // Check if closing point is a spike (this is so if the second point is
 140         // considered as a spike w.r.t. the last segment)
 141         if (point_is_spike_or_equal(*second, *ultimate, *first, strategy, robust_policy))
 142         {
 143             range::erase(range, first);
 144             if (BOOST_GEOMETRY_CONDITION(closed))
 145             {
 146                 // Remove closing last point
 147                 range::resize(range, boost::size(range) - 1);
 148                 // Add new closing point
 149                 range::push_back(range, range::front(range));
 150             }
 151             found = true;
 152         }
 153     } while(found && boost::size(range) > minsize);
 154 }
 155
 156
 157 }} // namespace detail::overlay
 158 #endif // DOXYGEN_NO_DETAIL
 159
 160
 161 }} // namespace boost::geometry
 162
 163
 164 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_APPEND_NO_DUPS_OR_SPIKES_HPP