173 lines
5.2 KiB
Plaintext
173 lines
5.2 KiB
Plaintext
/*=============================================================================
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Copyright (c) 2001-2011 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#if !defined(FUSION_POP_BACK_09172005_1038)
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#define FUSION_POP_BACK_09172005_1038
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#include <boost/fusion/support/config.hpp>
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#include <boost/fusion/view/iterator_range/iterator_range.hpp>
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#include <boost/fusion/sequence/intrinsic/begin.hpp>
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#include <boost/fusion/sequence/intrinsic/end.hpp>
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#include <boost/fusion/sequence/intrinsic/empty.hpp>
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#include <boost/fusion/iterator/iterator_adapter.hpp>
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#include <boost/fusion/iterator/next.hpp>
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#include <boost/mpl/minus.hpp>
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#include <boost/mpl/int.hpp>
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#include <boost/mpl/if.hpp>
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namespace boost { namespace fusion
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{
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template <typename Iterator_, bool IsLast>
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struct pop_back_iterator
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: iterator_adapter<
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pop_back_iterator<Iterator_, IsLast>
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, Iterator_>
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{
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typedef iterator_adapter<
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pop_back_iterator<Iterator_, IsLast>
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, Iterator_>
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base_type;
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static bool const is_last = IsLast;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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pop_back_iterator(Iterator_ const& iterator_base)
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: base_type(iterator_base) {}
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template <typename BaseIterator>
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struct make
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{
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typedef pop_back_iterator<BaseIterator, is_last> type;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type
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call(BaseIterator const& i)
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{
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return type(i);
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}
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};
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template <typename I, bool IsLast_>
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struct equal_to_helper
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: mpl::identity<typename I::iterator_base_type>
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{};
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template <typename I>
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struct equal_to_helper<I, true>
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: result_of::next<
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typename I::iterator_base_type>
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{};
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template <typename I1, typename I2>
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struct equal_to
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: result_of::equal_to<
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typename equal_to_helper<I1,
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(I2::is_last && !I1::is_last)>::type
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, typename equal_to_helper<I2,
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(I1::is_last && !I2::is_last)>::type
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>
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{};
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template <typename First, typename Last>
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struct distance
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: mpl::minus<
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typename result_of::distance<
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typename First::iterator_base_type
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, typename Last::iterator_base_type
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>::type
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, mpl::int_<(Last::is_last?1:0)>
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>::type
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{};
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template <typename Iterator, bool IsLast_>
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struct prior_impl
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{
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typedef typename Iterator::iterator_base_type base_type;
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typedef typename
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result_of::prior<base_type>::type
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base_prior;
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typedef pop_back_iterator<base_prior, false> type;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type
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call(Iterator const& i)
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{
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return type(fusion::prior(i.iterator_base));
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}
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};
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template <typename Iterator>
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struct prior_impl<Iterator, true>
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{
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// If this is the last iterator, we'll have to double back
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typedef typename Iterator::iterator_base_type base_type;
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typedef typename
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result_of::prior<
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typename result_of::prior<base_type>::type
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>::type
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base_prior;
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typedef pop_back_iterator<base_prior, false> type;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type
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call(Iterator const& i)
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{
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return type(fusion::prior(
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fusion::prior(i.iterator_base)));
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}
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};
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template <typename Iterator>
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struct prior : prior_impl<Iterator, Iterator::is_last>
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{};
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};
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namespace result_of
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{
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template <typename Sequence>
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struct pop_back
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{
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BOOST_MPL_ASSERT_NOT((result_of::empty<Sequence>));
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typedef pop_back_iterator<
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typename begin<Sequence>::type, false>
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begin_type;
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typedef pop_back_iterator<
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typename end<Sequence>::type, true>
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end_type;
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typedef
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iterator_range<begin_type, end_type>
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type;
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};
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}
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template <typename Sequence>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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inline typename result_of::pop_back<Sequence const>::type
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pop_back(Sequence const& seq)
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{
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typedef result_of::pop_back<Sequence const> comp;
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typedef typename comp::begin_type begin_type;
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typedef typename comp::end_type end_type;
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typedef typename comp::type result;
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return result(
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begin_type(fusion::begin(seq))
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, end_type(fusion::end(seq))
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);
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}
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}}
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#endif
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