67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
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// Copyright (c) 2002
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// Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland),
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// INRIA Sophia-Antipolis (France),
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// Max-Planck-Institute Saarbruecken (Germany),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Kernel_23/include/CGAL/Is_a_predicate.h $
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// $Id: Is_a_predicate.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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//
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// Author(s) : Sylvain Pion
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#ifndef CGAL_IS_A_PREDICATE_H
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#define CGAL_IS_A_PREDICATE_H
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// How to determine if a kernel functor is a predicate or a construction.
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#include <CGAL/basic.h>
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#include <CGAL/enum.h>
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namespace CGAL {
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namespace internal {
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// By default it's a construction
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template <typename Return_type>
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struct Return_type_of_predicate {
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typedef CGAL::Tag_false type;
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};
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// Specializations for predicates
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template <>
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struct Return_type_of_predicate<bool> {
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typedef CGAL::Tag_true type;
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};
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template <>
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struct Return_type_of_predicate<CGAL::Sign> {
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typedef CGAL::Tag_true type;
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};
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template <>
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struct Return_type_of_predicate<CGAL::Bounded_side> {
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typedef CGAL::Tag_true type;
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};
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template <>
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struct Return_type_of_predicate<CGAL::Angle> {
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typedef CGAL::Tag_true type;
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};
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} // namespace internal
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template <typename Functor>
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struct Is_a_predicate {
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typedef typename internal::Return_type_of_predicate<
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typename Functor::result_type>::type type;
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};
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} //namespace CGAL
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#endif // CGAL_IS_A_PREDICATE_H
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