mirror of https://github.com/CGAL/cgal
91 lines
2.8 KiB
C++
91 lines
2.8 KiB
C++
// Copyright (c) 2005 Stanford University (USA).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 3 of the License,
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// or (at your option) any later version.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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//
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//
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// Author(s) : Daniel Russel <drussel@alumni.princeton.edu>
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#ifndef CGAL_POLYNOMIAL_INTERNAL_DERIVATIVE_H
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#define CGAL_POLYNOMIAL_INTERNAL_DERIVATIVE_H
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#include <CGAL/Polynomial/basic.h>
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#include <iterator>
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#include <boost/iterator/iterator_facade.hpp>
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namespace CGAL { namespace POLYNOMIAL { namespace internal {
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template <class Fn>
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struct Derivative
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{
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private:
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typedef typename Fn::iterator Cit;
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struct It :
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public boost::iterator_facade<It,
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typename std::iterator_traits<typename Fn::iterator>::value_type,
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typename std::iterator_traits<typename Fn::iterator>::iterator_category,
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// Use value_type as reference (see
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// dereference() below())
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typename std::iterator_traits<typename Fn::iterator>::value_type,
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typename std::iterator_traits<typename Fn::iterator>::difference_type>
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{
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It(Cit it, int i): i_(i), cit_(it) {}
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It(){}
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private:
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typedef typename Fn::iterator MCit;
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typedef typename std::iterator_traits<MCit> Traits;
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public:
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typedef typename Traits::difference_type difference_type;
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typedef typename Traits::value_type value_type;
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private:
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friend class boost::iterator_core_access;
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value_type dereference() const { return value_type(i_)**cit_; }
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void increment() { ++i_; ++cit_;}
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bool equal(const It& i) const { return (i_ == i.i_) && (cit_ == i.cit_); }
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void decrement() { --i_; --cit_;}
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void advance(const difference_type n) { i_ += n; cit_ += n; }
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difference_type distance_to(const It& o) const { return o.cit_ - cit_; }
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protected:
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int i_;
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MCit cit_;
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}; // end nested struct It
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public:
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typedef Fn result_type;
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typedef Fn argument_type;
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result_type operator()(const argument_type &o) const
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{
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if (o.is_constant()) { return result_type(typename result_type::NT(0)); }
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else {
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It b(o.begin(),0);
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++b;
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return result_type(b, It(o.end(), o.degree()+1));
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}
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}
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void write(std::ostream &out) const
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{
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out << "diff";
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}
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};
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} } } //namespace CGAL::POLYNOMIAL::internal
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#endif
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