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1 |
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2 #ifndef BOOST_MPL_INDEX_IF_HPP_INCLUDED |
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3 #define BOOST_MPL_INDEX_IF_HPP_INCLUDED |
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4 |
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5 // Copyright Eric Friedman 2003 |
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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/index_if.hpp,v $ |
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14 // $Date: 2004/09/02 15:40:41 $ |
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15 // $Revision: 1.7 $ |
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16 |
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17 #include <boost/mpl/aux_/find_if_pred.hpp> |
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18 #include <boost/mpl/begin_end.hpp> |
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19 #include <boost/mpl/if.hpp> |
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20 #include <boost/mpl/int.hpp> |
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21 #include <boost/mpl/iter_fold_if.hpp> |
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22 #include <boost/mpl/next.hpp> |
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23 #include <boost/mpl/void.hpp> |
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24 #include <boost/mpl/aux_/na_spec.hpp> |
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25 #include <boost/mpl/aux_/lambda_support.hpp> |
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26 #include <boost/type_traits/is_same.hpp> |
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27 |
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28 namespace boost { namespace mpl { |
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29 |
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30 template< |
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31 typename BOOST_MPL_AUX_NA_PARAM(Sequence) |
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32 , typename BOOST_MPL_AUX_NA_PARAM(Predicate) |
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33 > |
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34 struct index_if |
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35 { |
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36 typedef typename iter_fold_if< |
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37 Sequence |
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38 , int_<0> |
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39 , next<> |
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40 , aux::find_if_pred<Predicate> |
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41 >::type result_; |
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42 |
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43 typedef typename end<Sequence>::type not_found_; |
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44 typedef typename first<result_>::type result_index_; |
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45 typedef typename second<result_>::type result_iterator_; |
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46 |
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47 typedef typename if_< |
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48 is_same< result_iterator_,not_found_ > |
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49 , void_ |
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50 , result_index_ |
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51 >::type type; |
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52 |
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53 BOOST_MPL_AUX_LAMBDA_SUPPORT(2,index_if,(Sequence,Predicate)) |
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54 }; |
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55 |
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56 BOOST_MPL_AUX_NA_SPEC(2, index_if) |
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57 |
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58 }} |
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59 |
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60 #endif // BOOST_MPL_INDEX_IF_HPP_INCLUDED |