76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
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// Copyright (c) 2011 INRIA Saclay Ile-de-France (France).
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// All rights reserved.
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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 part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/STL_Extension/include/CGAL/is_iterator.h $
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// $Id: is_iterator.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) : Marc Glisse
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#ifndef CGAL_IS_ITERATOR_H
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#define CGAL_IS_ITERATOR_H
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#include <iterator>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/type_traits/is_pointer.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/mpl/has_xxx.hpp>
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namespace CGAL {
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namespace internal {
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BOOST_MPL_HAS_XXX_TRAIT_DEF(iterator_category)
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BOOST_MPL_HAS_XXX_TRAIT_DEF(value_type)
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BOOST_MPL_HAS_XXX_TRAIT_DEF(difference_type)
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BOOST_MPL_HAS_XXX_TRAIT_DEF(pointer)
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BOOST_MPL_HAS_XXX_TRAIT_DEF(reference)
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//We request the type to be either a pointer or to
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//provide all 5 nested types provided by iterator_traits
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template <class T> struct is_iterator_ {
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enum { value =
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( has_iterator_category<T>::value &&
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has_value_type<T>::value &&
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has_difference_type<T>::value &&
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has_pointer<T>::value &&
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has_reference<T>::value
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)
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|| boost::is_pointer<T>::value };
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};
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template <class T,class U,bool=is_iterator_<T>::value>
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struct is_iterator_type_ {
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enum { value=false };
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};
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template <class T,class U> struct is_iterator_type_<T,U,true> :
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//boost::is_base_of<U,typename std::iterator_traits<T>::iterator_category>
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boost::is_convertible<typename std::iterator_traits<T>::iterator_category,U>
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{};
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}
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// NOTE: we don't want the real std::decay or functions are included
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template <class T> struct is_iterator :
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internal::is_iterator_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type> {};
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template <class T,class Tag> struct is_iterator_type :
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internal::is_iterator_type_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type,Tag> {};
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template <class T,class U,bool=is_iterator<T>::value> struct is_iterator_to {
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enum { value=false };
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};
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template <class T,class U> struct is_iterator_to<T,U,true> :
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boost::is_convertible<typename std::iterator_traits<T>::value_type,U>
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{ };
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}
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#endif // CGAL_IS_ITERATOR_H
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