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2 | #ifndef BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED |
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3 | #define BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_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 | // $Id: single_element_iter.hpp 49267 2008-10-11 06:19:02Z agurtovoy $ |
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14 | // $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $ |
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15 | // $Revision: 49267 $ |
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16 | |
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17 | #include <boost/mpl/iterator_tags.hpp> |
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18 | #include <boost/mpl/advance_fwd.hpp> |
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19 | #include <boost/mpl/distance_fwd.hpp> |
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20 | #include <boost/mpl/next_prior.hpp> |
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21 | #include <boost/mpl/deref.hpp> |
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22 | #include <boost/mpl/int.hpp> |
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23 | #include <boost/mpl/aux_/nttp_decl.hpp> |
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24 | #include <boost/mpl/aux_/value_wknd.hpp> |
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25 | #include <boost/mpl/aux_/config/ctps.hpp> |
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26 | |
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27 | namespace boost { namespace mpl { |
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28 | |
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29 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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30 | |
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31 | namespace aux { |
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32 | |
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33 | template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_) > |
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34 | struct sel_iter; |
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35 | |
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36 | template< typename T > |
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37 | struct sel_iter<T,0> |
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38 | { |
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39 | typedef random_access_iterator_tag category; |
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40 | typedef sel_iter<T,1> next; |
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41 | typedef T type; |
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42 | }; |
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43 | |
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44 | template< typename T > |
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45 | struct sel_iter<T,1> |
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46 | { |
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47 | typedef random_access_iterator_tag category; |
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48 | typedef sel_iter<T,0> prior; |
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49 | }; |
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50 | |
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51 | } // namespace aux |
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52 | |
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53 | template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_), typename Distance > |
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54 | struct advance< aux::sel_iter<T,is_last_>,Distance> |
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55 | { |
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56 | typedef aux::sel_iter< |
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57 | T |
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58 | , ( is_last_ + BOOST_MPL_AUX_NESTED_VALUE_WKND(int, Distance) ) |
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59 | > type; |
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60 | }; |
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61 | |
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62 | template< |
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63 | typename T |
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64 | , BOOST_MPL_AUX_NTTP_DECL(int, l1) |
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65 | , BOOST_MPL_AUX_NTTP_DECL(int, l2) |
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66 | > |
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67 | struct distance< aux::sel_iter<T,l1>, aux::sel_iter<T,l2> > |
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68 | : int_<( l2 - l1 )> |
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69 | { |
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70 | }; |
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71 | |
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72 | #else |
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73 | |
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74 | namespace aux { |
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75 | |
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76 | struct sel_iter_tag; |
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77 | |
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78 | template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_) > |
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79 | struct sel_iter |
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80 | { |
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81 | enum { pos_ = is_last_ }; |
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82 | typedef aux::sel_iter_tag tag; |
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83 | typedef random_access_iterator_tag category; |
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84 | |
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85 | typedef sel_iter<T,(is_last_ + 1)> next; |
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86 | typedef sel_iter<T,(is_last_ - 1)> prior; |
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87 | typedef T type; |
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88 | }; |
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89 | |
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90 | } // namespace aux |
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91 | |
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92 | template<> struct advance_impl<aux::sel_iter_tag> |
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93 | { |
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94 | template< typename Iterator, typename N > struct apply |
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95 | { |
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96 | enum { pos_ = Iterator::pos_, n_ = N::value }; |
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97 | typedef aux::sel_iter< |
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98 | typename Iterator::type |
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99 | , (pos_ + n_) |
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100 | > type; |
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101 | }; |
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102 | }; |
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103 | |
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104 | template<> struct distance_impl<aux::sel_iter_tag> |
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105 | { |
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106 | template< typename Iter1, typename Iter2 > struct apply |
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107 | { |
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108 | enum { pos1_ = Iter1::pos_, pos2_ = Iter2::pos_ }; |
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109 | typedef int_<( pos2_ - pos1_ )> type; |
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110 | BOOST_STATIC_CONSTANT(int, value = ( pos2_ - pos1_ )); |
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111 | }; |
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112 | }; |
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113 | |
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114 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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115 | |
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116 | }} |
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117 | |
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118 | #endif // BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED |
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