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93 lines
2.3 KiB
93 lines
2.3 KiB
// Boost.Geometry (aka GGL, Generic Geometry Library) |
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// Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands. |
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// Copyright (c) 2008-2011 Bruno Lalande, Paris, France. |
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// Copyright (c) 2009-2011 Mateusz Loskot, London, UK. |
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// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library |
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// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. |
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// Use, modification and distribution is subject to the Boost Software License, |
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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#ifndef BOOST_GEOMETRY_STRATEGIES_SIDE_INFO_HPP |
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#define BOOST_GEOMETRY_STRATEGIES_SIDE_INFO_HPP |
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#include <utility> |
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namespace boost { namespace geometry |
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{ |
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/*! |
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\brief Class side_info: small class wrapping for sides (-1,0,1) |
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*/ |
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class side_info |
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{ |
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public : |
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inline side_info(int side_a1 = 0, int side_a2 = 0, |
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int side_b1 = 0, int side_b2 = 0) |
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{ |
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sides[0].first = side_a1; |
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sides[0].second = side_a2; |
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sides[1].first = side_b1; |
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sides[1].second = side_b2; |
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} |
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template <int Which> |
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inline void set(int first, int second) |
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{ |
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sides[Which].first = first; |
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sides[Which].second = second; |
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} |
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template <int Which, int Index> |
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inline int get() const |
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{ |
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return Index == 0 ? sides[Which].first : sides[Which].second; |
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} |
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// Returns true if both lying on the same side WRT the other |
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// (so either 1,1 or -1-1) |
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template <int Which> |
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inline bool same() const |
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{ |
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return sides[Which].first * sides[Which].second == 1; |
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} |
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inline bool collinear() const |
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{ |
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return sides[0].first == 0 |
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&& sides[0].second == 0 |
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&& sides[1].first == 0 |
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&& sides[1].second == 0; |
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} |
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// If one of the segments is collinear, the other must be as well. |
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// So handle it as collinear. |
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// (In floating point margins it can occur that one of them is 1!) |
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inline bool as_collinear() const |
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{ |
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return sides[0].first * sides[0].second == 0 |
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|| sides[1].first * sides[1].second == 0; |
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} |
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inline void reverse() |
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{ |
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std::swap(sides[0], sides[1]); |
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} |
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private : |
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std::pair<int, int> sides[2]; |
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}; |
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}} // namespace boost::geometry |
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#endif // BOOST_GEOMETRY_STRATEGIES_SIDE_INFO_HPP
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