mirror of https://github.com/CGAL/cgal
101 lines
2.4 KiB
C++
101 lines
2.4 KiB
C++
// Copyright (c) 2014 GeometryFactory (France). 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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// $URL$
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// $Id$
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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) : Andreas Fabri
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#ifndef CGAL_ITERATOR_RANGE_H
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#define CGAL_ITERATOR_RANGE_H
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#include <CGAL/tuple.h>
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#include <utility>
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#include <boost/foreach.hpp>
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namespace CGAL {
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/*!
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\ingroup PkgSTLExtensionRef
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`CGAL::Iterator_range` encapsulates two iterators so they fulfill the `ForwardRange` concept.
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The class is essentially a clone of <A
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href="https://www.boost.org/doc/libs/1_55_0/libs/range/doc/html/range/reference/utilities/iterator_range.html">`boost::iterator_range`</A>,
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and it additionally is derived from `std::pair`, so that one can apply `boost::tie`.
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*/
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template <typename I>
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class Iterator_range : public std::pair<I, I>
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{
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typedef std::pair<I, I> Base;
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public:
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typedef I iterator;
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typedef I const_iterator;
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Iterator_range() = default;
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Iterator_range(I b, I e)
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: Base(b, e) {}
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Iterator_range(const std::pair<I, I>& ip)
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: Base(ip) {}
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I begin() const { return this->first; }
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I end() const { return this->second; }
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/// returns `std::distance(begin(), end())`
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std::size_t size() const { return static_cast<std::size_t>(std::distance(begin(), end())); }
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/// returns `std::distance(begin(), end())==0`
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bool empty() const { return begin() == end(); }
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operator std::tuple<I&, I&>()
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{
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return std::tuple<I&, I&>{this->first, this->second};
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}
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operator std::tuple<const I&, const I&>() const
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{
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return std::tuple<const I&, const I&>{this->first, this->second};
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}
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template <template<class...> class Container>
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auto to() const
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{
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using V = std::remove_cv_t<std::remove_reference_t<decltype(*begin())>>;
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return Container<V>(begin(), end());
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}
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};
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template <typename T>
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Iterator_range<T>
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make_range(const T& b, const T&e)
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{
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return Iterator_range<T>(b,e);
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}
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template <typename T>
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Iterator_range<T>
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make_range(const std::pair<T,T>& p)
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{
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return Iterator_range<T>(p.first,p.second);
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}
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} // namespace CGAL
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namespace boost::foreach {
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template<typename T>
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struct is_lightweight_proxy<CGAL::Iterator_range<T>> : boost::mpl::true_ {};
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}
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#if CGAL_CXX20 && __cpp_lib_ranges >= 201911L
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# include <ranges>
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template<typename I>
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inline constexpr bool std::ranges::enable_borrowed_range<CGAL::Iterator_range<I>> = true;
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#endif // C++20
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#endif // CGAL_ITERATOR_RANGE_H
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