108 lines
2.7 KiB
Plaintext
108 lines
2.7 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_ADVANCE_09172005_1149)
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#define FUSION_ADVANCE_09172005_1149
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#include <boost/fusion/support/config.hpp>
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#include <boost/mpl/int.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/identity.hpp>
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#include <boost/fusion/iterator/next.hpp>
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#include <boost/fusion/iterator/prior.hpp>
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namespace boost { namespace fusion { namespace advance_detail
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{
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// Default advance implementation, perform next(i)
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// or prior(i) N times.
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template <typename Iterator, int N>
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struct forward;
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template <typename Iterator, int N>
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struct next_forward
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{
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typedef typename
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forward<
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typename result_of::next<Iterator>::type
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, N-1
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>::type
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type;
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};
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template <typename Iterator, int N>
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struct forward
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{
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typedef typename
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mpl::eval_if_c<
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(N == 0)
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, mpl::identity<Iterator>
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, next_forward<Iterator, N>
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>::type
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type;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type const&
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call(type const& i)
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{
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return i;
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}
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template <typename I>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type
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call(I const& i)
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{
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return call(fusion::next(i));
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}
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};
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template <typename Iterator, int N>
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struct backward;
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template <typename Iterator, int N>
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struct next_backward
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{
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typedef typename
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backward<
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typename result_of::prior<Iterator>::type
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, N+1
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>::type
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type;
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};
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template <typename Iterator, int N>
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struct backward
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{
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typedef typename
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mpl::eval_if_c<
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(N == 0)
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, mpl::identity<Iterator>
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, next_backward<Iterator, N>
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>::type
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type;
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type const&
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call(type const& i)
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{
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return i;
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}
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template <typename I>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static type
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call(I const& i)
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{
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return call(fusion::prior(i));
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}
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};
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}}}
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#endif
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