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| 2 | #ifndef BOOST_MPL_AUX_ERASE_IMPL_HPP_INCLUDED |
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| 3 | #define BOOST_MPL_AUX_ERASE_IMPL_HPP_INCLUDED |
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| 4 | |
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| 5 | // Copyright Aleksey Gurtovoy 2000-2004 |
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| 6 | // |
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| 7 | // Distributed under the Boost Software License, Version 1.0. |
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| 8 | // (See accompanying file LICENSE_1_0.txt or copy at |
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| 9 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 10 | // |
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| 11 | // See http://www.boost.org/libs/mpl for documentation. |
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| 12 | |
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| 13 | // $Source: /cvsroot/boost/boost/boost/mpl/aux_/erase_impl.hpp,v $ |
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| 14 | // $Date: 2004/09/02 15:40:43 $ |
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| 15 | // $Revision: 1.4 $ |
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| 16 | |
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| 17 | #include <boost/mpl/clear.hpp> |
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| 18 | #include <boost/mpl/push_front.hpp> |
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| 19 | #include <boost/mpl/reverse_fold.hpp> |
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| 20 | #include <boost/mpl/iterator_range.hpp> |
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| 21 | #include <boost/mpl/next.hpp> |
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| 22 | #include <boost/mpl/aux_/na.hpp> |
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| 23 | |
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| 24 | namespace boost { namespace mpl { |
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| 25 | |
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| 26 | // default implementation; conrete sequences might override it by |
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| 27 | // specializing either the 'erase_impl' or the primary 'erase' template |
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| 28 | |
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| 29 | template< typename Tag > |
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| 30 | struct erase_impl |
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| 31 | { |
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| 32 | template< |
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| 33 | typename Sequence |
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| 34 | , typename First |
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| 35 | , typename Last |
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| 36 | > |
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| 37 | struct apply |
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| 38 | { |
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| 39 | typedef typename if_na< Last,typename next<First>::type >::type last_; |
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| 40 | |
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| 41 | // 1st half: [begin, first) |
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| 42 | typedef iterator_range< |
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| 43 | typename begin<Sequence>::type |
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| 44 | , First |
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| 45 | > first_half_; |
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| 46 | |
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| 47 | // 2nd half: [last, end) ... that is, [last + 1, end) |
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| 48 | typedef iterator_range< |
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| 49 | last_ |
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| 50 | , typename end<Sequence>::type |
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| 51 | > second_half_; |
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| 52 | |
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| 53 | typedef typename reverse_fold< |
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| 54 | second_half_ |
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| 55 | , typename clear<Sequence>::type |
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| 56 | , push_front<_,_> |
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| 57 | >::type half_sequence_; |
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| 58 | |
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| 59 | typedef typename reverse_fold< |
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| 60 | first_half_ |
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| 61 | , half_sequence_ |
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| 62 | , push_front<_,_> |
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| 63 | >::type type; |
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| 64 | }; |
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| 65 | }; |
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| 66 | |
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| 67 | }} |
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| 68 | |
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| 69 | #endif // BOOST_MPL_AUX_ERASE_IMPL_HPP_INCLUDED |
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