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Diffstat (limited to 'boost/geometry/algorithms/detail/is_valid/linear.hpp')
-rw-r--r-- | boost/geometry/algorithms/detail/is_valid/linear.hpp | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/boost/geometry/algorithms/detail/is_valid/linear.hpp b/boost/geometry/algorithms/detail/is_valid/linear.hpp new file mode 100644 index 0000000000..244df9b035 --- /dev/null +++ b/boost/geometry/algorithms/detail/is_valid/linear.hpp @@ -0,0 +1,125 @@ +// Boost.Geometry (aka GGL, Generic Geometry Library) + +// Copyright (c) 2014, Oracle and/or its affiliates. + +// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle + +// Licensed under the Boost Software License version 1.0. +// http://www.boost.org/users/license.html + +#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP +#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP + +#include <cstddef> + +#include <boost/range.hpp> + +#include <boost/geometry/core/closure.hpp> +#include <boost/geometry/core/point_type.hpp> +#include <boost/geometry/core/tags.hpp> + +#include <boost/geometry/util/range.hpp> + +#include <boost/geometry/algorithms/equals.hpp> +#include <boost/geometry/algorithms/detail/check_iterator_range.hpp> +#include <boost/geometry/algorithms/detail/is_valid/has_spikes.hpp> +#include <boost/geometry/algorithms/detail/num_distinct_consecutive_points.hpp> + +#include <boost/geometry/algorithms/dispatch/is_valid.hpp> + + +namespace boost { namespace geometry +{ + +#ifndef DOXYGEN_NO_DETAIL +namespace detail { namespace is_valid +{ + + +template <typename Linestring, bool AllowSpikes> +struct is_valid_linestring +{ + static inline bool apply(Linestring const& linestring) + { + std::size_t num_distinct = detail::num_distinct_consecutive_points + < + Linestring, + 3u, + true, + not_equal_to<typename point_type<Linestring>::type> + >::apply(linestring); + + if ( num_distinct < 2u ) + { + return false; + } + + return num_distinct == 2u + || AllowSpikes + || !has_spikes<Linestring, closed>::apply(linestring); + } +}; + + +}} // namespace detail::is_valid +#endif // DOXYGEN_NO_DETAIL + + + + +#ifndef DOXYGEN_NO_DISPATCH +namespace dispatch +{ + + +// A linestring is a curve. +// A curve is 1-dimensional so it has to have at least two distinct +// points. +// A curve is simple if it does not pass through the same point twice, +// with the possible exception of its two endpoints +// +// There is an option here as to whether spikes are allowed for linestrings; +// here we pass this as an additional template parameter: allow_spikes +// If allow_spikes is set to true, spikes are allowed, false otherwise. +// By default, spikes are disallowed +// +// Reference: OGC 06-103r4 (6.1.6.1) +template <typename Linestring, bool AllowSpikes> +struct is_valid<Linestring, linestring_tag, AllowSpikes> + : detail::is_valid::is_valid_linestring<Linestring, AllowSpikes> +{}; + + +// A MultiLinestring is a MultiCurve +// A MultiCurve is simple if all of its elements are simple and the +// only intersections between any two elements occur at Points that +// are on the boundaries of both elements. +// +// Reference: OGC 06-103r4 (6.1.8.1; Fig. 9) +template <typename MultiLinestring, bool AllowSpikes> +struct is_valid<MultiLinestring, multi_linestring_tag, AllowSpikes> +{ + static inline bool apply(MultiLinestring const& multilinestring) + { + return detail::check_iterator_range + < + detail::is_valid::is_valid_linestring + < + typename boost::range_value<MultiLinestring>::type, + AllowSpikes + >, + false // do not allow empty multilinestring + >::apply(boost::begin(multilinestring), + boost::end(multilinestring)); + } +}; + + +} // namespace dispatch +#endif // DOXYGEN_NO_DISPATCH + + +}} // namespace boost::geometry + + +#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_IS_VALID_LINEAR_HPP |