cgal/STL_Extension/include/CGAL/is_iterator.h

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2.5 KiB
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// Copyright (c) 2011 INRIA Saclay Ile-de-France (France).
// All rights reserved.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL$
// $Id$
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Marc Glisse
#ifndef CGAL_IS_ITERATOR_H
#define CGAL_IS_ITERATOR_H
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/is_pointer.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/mpl/has_xxx.hpp>
#include <boost/mpl/logical.hpp>
#include <iterator>
namespace CGAL {
namespace internal {
BOOST_MPL_HAS_XXX_TRAIT_DEF(iterator_category)
BOOST_MPL_HAS_XXX_TRAIT_DEF(value_type)
BOOST_MPL_HAS_XXX_TRAIT_DEF(difference_type)
BOOST_MPL_HAS_XXX_TRAIT_DEF(pointer)
BOOST_MPL_HAS_XXX_TRAIT_DEF(reference)
//We request the type to be either a pointer or to
//provide all 5 nested types provided by iterator_traits
template <class T>
struct is_iterator_
: public boost::mpl::or_<
boost::mpl::and_<
has_iterator_category<T>,
has_value_type<T>,
has_difference_type<T>,
has_pointer<T>,
has_reference<T> >,
boost::is_pointer<T> >
{ };
template <class T, class U, bool = is_iterator_<T>::value>
struct is_iterator_type_
: public boost::mpl::false_
{ };
template <class T,class U>
struct is_iterator_type_<T, U, true>
: public //boost::is_base_of<U,typename std::iterator_traits<T>::iterator_category>
boost::is_convertible<typename std::iterator_traits<T>::iterator_category, U>
{ };
} // namespace internal
// NOTE: we don't want the real std::decay or functions are included
template <class T>
struct is_iterator
: public internal::is_iterator_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type>
{ };
template <class T, class Tag>
struct is_iterator_type
: public internal::is_iterator_type_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type, Tag>
{ };
template <class T, class U, bool = is_iterator<T>::value>
struct is_iterator_to
: public boost::mpl::false_
{ };
template <class T, class U>
struct is_iterator_to<T, U, true>
: public boost::is_convertible<typename std::iterator_traits<T>::value_type, U>
{ };
} // namespace CGAL
#endif // CGAL_IS_ITERATOR_H