119 lines
3.0 KiB
C++
119 lines
3.0 KiB
C++
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#ifndef BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED
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#define BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED
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// Copyright Aleksey Gurtovoy 2000-2004
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/mpl for documentation.
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// $Id: single_element_iter.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
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// $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $
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// $Revision: 49267 $
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#include <boost/mpl/iterator_tags.hpp>
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#include <boost/mpl/advance_fwd.hpp>
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#include <boost/mpl/distance_fwd.hpp>
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#include <boost/mpl/next_prior.hpp>
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#include <boost/mpl/deref.hpp>
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#include <boost/mpl/int.hpp>
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#include <boost/mpl/aux_/nttp_decl.hpp>
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#include <boost/mpl/aux_/value_wknd.hpp>
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#include <boost/mpl/aux_/config/ctps.hpp>
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namespace boost { namespace mpl {
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#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
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namespace aux {
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template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_) >
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struct sel_iter;
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template< typename T >
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struct sel_iter<T,0>
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{
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typedef random_access_iterator_tag category;
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typedef sel_iter<T,1> next;
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typedef T type;
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};
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template< typename T >
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struct sel_iter<T,1>
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{
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typedef random_access_iterator_tag category;
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typedef sel_iter<T,0> prior;
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};
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} // namespace aux
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template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_), typename Distance >
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struct advance< aux::sel_iter<T,is_last_>,Distance>
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{
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typedef aux::sel_iter<
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T
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, ( is_last_ + BOOST_MPL_AUX_NESTED_VALUE_WKND(int, Distance) )
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> type;
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};
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template<
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typename T
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, BOOST_MPL_AUX_NTTP_DECL(int, l1)
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, BOOST_MPL_AUX_NTTP_DECL(int, l2)
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>
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struct distance< aux::sel_iter<T,l1>, aux::sel_iter<T,l2> >
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: int_<( l2 - l1 )>
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{
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};
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#else
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namespace aux {
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struct sel_iter_tag;
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template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_) >
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struct sel_iter
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{
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enum { pos_ = is_last_ };
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typedef aux::sel_iter_tag tag;
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typedef random_access_iterator_tag category;
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typedef sel_iter<T,(is_last_ + 1)> next;
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typedef sel_iter<T,(is_last_ - 1)> prior;
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typedef T type;
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};
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} // namespace aux
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template<> struct advance_impl<aux::sel_iter_tag>
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{
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template< typename Iterator, typename N > struct apply
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{
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enum { pos_ = Iterator::pos_, n_ = N::value };
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typedef aux::sel_iter<
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typename Iterator::type
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, (pos_ + n_)
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> type;
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};
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};
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template<> struct distance_impl<aux::sel_iter_tag>
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{
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template< typename Iter1, typename Iter2 > struct apply
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{
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enum { pos1_ = Iter1::pos_, pos2_ = Iter2::pos_ };
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typedef int_<( pos2_ - pos1_ )> type;
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BOOST_STATIC_CONSTANT(int, value = ( pos2_ - pos1_ ));
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};
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};
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#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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}}
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#endif // BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED
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