mirror of https://github.com/CGAL/cgal
100 lines
2.3 KiB
C++
100 lines
2.3 KiB
C++
// Copyright (c) 2020 GeometryFactory (France).
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// 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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// Author(s) : Simon Giraudot
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//
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#ifndef CGAL_PCA_SUBITERATOR_H
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#define CGAL_PCA_SUBITERATOR_H
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#include <boost/iterator/iterator_facade.hpp>
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namespace CGAL
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{
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template <typename InputIterator, typename ValueType, int Size>
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class Subiterator
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: public boost::iterator_facade<Subiterator<InputIterator, ValueType, Size>,
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ValueType,
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std::input_iterator_tag>
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{
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public:
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using Self = Subiterator<InputIterator, ValueType, Size>;
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using Facade = boost::iterator_facade<Self, ValueType, std::input_iterator_tag>;
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using Input_type = typename std::iterator_traits<InputIterator>::value_type;
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using Output_type = ValueType;
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using Converter = std::function<Output_type(const Input_type&, int)>;
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private:
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Converter m_converter;
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int m_next_index;
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InputIterator m_base;
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mutable Output_type m_current;
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public:
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Subiterator() { }
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Subiterator(InputIterator begin, const Converter& converter)
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: m_converter(converter), m_next_index(0), m_base(begin)
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{ }
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Subiterator(InputIterator end)
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: m_next_index(0), m_base(end)
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{ }
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private:
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friend class boost::iterator_core_access;
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void increment()
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{
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++ m_next_index;
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if (m_next_index == Size)
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{
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++ m_base;
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m_next_index = 0;
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}
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}
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bool equal(const Self& other) const
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{
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return this->m_base == other.m_base && this->m_next_index == other.m_next_index;
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}
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Output_type& dereference() const
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{
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m_current = m_converter (*m_base, m_next_index);
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return const_cast<Output_type&>(m_current);
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}
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};
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template <typename ValueType, int Size, typename InputIterator>
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Subiterator<InputIterator, ValueType, Size>
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make_subiterator (InputIterator begin,
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const typename Subiterator<InputIterator, ValueType, Size>::Converter& converter)
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{
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return Subiterator<InputIterator, ValueType, Size>(begin, converter);
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}
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template <typename ValueType, int Size, typename InputIterator>
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Subiterator<InputIterator, ValueType, Size>
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make_subiterator (InputIterator end)
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{
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return Subiterator<InputIterator, ValueType, Size>(end);
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}
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} // namespace CGAL
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#endif // CGAL_PCA_SUBITERATOR_H
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