Chris@16: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@16: 
Chris@16: // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
Chris@16: // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
Chris@16: // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
Chris@16: 
Chris@16: // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
Chris@16: // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software License,
Chris@16: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GEOMETRY_STRATEGIES_SIDE_INFO_HPP
Chris@16: #define BOOST_GEOMETRY_STRATEGIES_SIDE_INFO_HPP
Chris@16: 
Chris@16: #include <cmath>
Chris@16: #include <utility>
Chris@101: 
Chris@101: #if defined(BOOST_GEOMETRY_DEBUG_INTERSECTION) || defined(BOOST_GEOMETRY_DEBUG_ROBUSTNESS)
Chris@101: #  include <iostream>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost { namespace geometry
Chris@16: {
Chris@16: 
Chris@16: // Silence warning C4127: conditional expression is constant
Chris@16: #if defined(_MSC_VER)
Chris@101: #pragma warning(push)
Chris@101: #pragma warning(disable : 4127)
Chris@16: #endif
Chris@16: 
Chris@16: /*!
Chris@16: \brief Class side_info: small class wrapping for sides (-1,0,1)
Chris@16: */
Chris@16: class side_info
Chris@16: {
Chris@16: public :
Chris@16:     inline side_info(int side_a1 = 0, int side_a2 = 0,
Chris@16:             int side_b1 = 0, int side_b2 = 0)
Chris@16:     {
Chris@16:         sides[0].first = side_a1;
Chris@16:         sides[0].second = side_a2;
Chris@16:         sides[1].first = side_b1;
Chris@16:         sides[1].second = side_b2;
Chris@16:     }
Chris@16: 
Chris@16:     template <int Which>
Chris@16:     inline void set(int first, int second)
Chris@16:     {
Chris@16:         sides[Which].first = first;
Chris@16:         sides[Which].second = second;
Chris@16:     }
Chris@16: 
Chris@16:     template <int Which, int Index>
Chris@16:     inline void correct_to_zero()
Chris@16:     {
Chris@16:         if (Index == 0)
Chris@16:         {
Chris@16:             sides[Which].first = 0;
Chris@16:         }
Chris@16:         else
Chris@16:         {
Chris@16:             sides[Which].second = 0;
Chris@16:         }
Chris@16:     }
Chris@16: 
Chris@16:     template <int Which, int Index>
Chris@16:     inline int get() const
Chris@16:     {
Chris@16:         return Index == 0 ? sides[Which].first : sides[Which].second;
Chris@16:     }
Chris@16: 
Chris@16: 
Chris@16:     // Returns true if both lying on the same side WRT the other
Chris@16:     // (so either 1,1 or -1-1)
Chris@16:     template <int Which>
Chris@16:     inline bool same() const
Chris@16:     {
Chris@16:         return sides[Which].first * sides[Which].second == 1;
Chris@16:     }
Chris@16: 
Chris@16:     inline bool collinear() const
Chris@16:     {
Chris@16:         return sides[0].first == 0
Chris@16:             && sides[0].second == 0
Chris@16:             && sides[1].first == 0
Chris@16:             && sides[1].second == 0;
Chris@16:     }
Chris@16: 
Chris@16:     inline bool crossing() const
Chris@16:     {
Chris@16:         return sides[0].first * sides[0].second == -1
Chris@16:             && sides[1].first * sides[1].second == -1;
Chris@16:     }
Chris@16: 
Chris@16:     inline bool touching() const
Chris@16:     {
Chris@16:         return (sides[0].first * sides[1].first == -1
Chris@16:             && sides[0].second == 0 && sides[1].second == 0)
Chris@16:             || (sides[1].first * sides[0].first == -1
Chris@16:             && sides[1].second == 0 && sides[0].second == 0);
Chris@16:     }
Chris@16: 
Chris@16:     template <int Which>
Chris@16:     inline bool one_touching() const
Chris@16:     {
Chris@16:         // This is normally a situation which can't occur:
Chris@16:         // If one is completely left or right, the other cannot touch
Chris@16:         return one_zero<Which>()
Chris@16:             && sides[1 - Which].first * sides[1 - Which].second == 1;
Chris@16:     }
Chris@16: 
Chris@16:     inline bool meeting() const
Chris@16:     {
Chris@16:         // Two of them (in each segment) zero, two not
Chris@16:         return one_zero<0>() && one_zero<1>();
Chris@16:     }
Chris@16: 
Chris@16:     template <int Which>
Chris@16:     inline bool zero() const
Chris@16:     {
Chris@16:         return sides[Which].first == 0 && sides[Which].second == 0;
Chris@16:     }
Chris@16: 
Chris@16:     template <int Which>
Chris@16:     inline bool one_zero() const
Chris@16:     {
Chris@16:         return (sides[Which].first == 0 && sides[Which].second != 0)
Chris@16:             || (sides[Which].first != 0 && sides[Which].second == 0);
Chris@16:     }
Chris@16: 
Chris@16:     inline bool one_of_all_zero() const
Chris@16:     {
Chris@16:         int const sum = std::abs(sides[0].first)
Chris@16:                 + std::abs(sides[0].second)
Chris@16:                 + std::abs(sides[1].first)
Chris@16:                 + std::abs(sides[1].second);
Chris@16:         return sum == 3;
Chris@16:     }
Chris@16: 
Chris@16: 
Chris@16:     template <int Which>
Chris@16:     inline int zero_index() const
Chris@16:     {
Chris@16:         return sides[Which].first == 0 ? 0 : 1;
Chris@16:     }
Chris@16: 
Chris@101: #if defined(BOOST_GEOMETRY_DEBUG_INTERSECTION) || defined(BOOST_GEOMETRY_DEBUG_ROBUSTNESS)
Chris@16:     inline void debug() const
Chris@16:     {
Chris@16:         std::cout << sides[0].first << " "
Chris@16:             << sides[0].second << " "
Chris@16:             << sides[1].first << " "
Chris@101:             << sides[1].second
Chris@16:             << std::endl;
Chris@16:     }
Chris@16: #endif
Chris@16: 
Chris@16:     inline void reverse()
Chris@16:     {
Chris@16:         std::swap(sides[0], sides[1]);
Chris@16:     }
Chris@16: 
Chris@16: //private :
Chris@16:     std::pair<int, int> sides[2];
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@101: #pragma warning(pop)
Chris@16: #endif
Chris@16: 
Chris@16: }} // namespace boost::geometry
Chris@16: 
Chris@16: 
Chris@16: #endif // BOOST_GEOMETRY_STRATEGIES_SIDE_INFO_HPP