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1 #ifndef POINTEE_DWA200415_HPP |
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2 # define POINTEE_DWA200415_HPP |
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3 |
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4 // |
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5 // Copyright David Abrahams 2004. Use, modification and distribution is |
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6 // subject to the Boost Software License, Version 1.0. (See accompanying |
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7 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
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8 // |
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9 // typename pointee<P>::type provides the pointee type of P. |
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10 // |
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11 // For example, it is T for T* and X for shared_ptr<X>. |
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12 // |
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13 // http://www.boost.org/libs/iterator/doc/pointee.html |
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14 // |
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15 |
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16 # include <boost/detail/is_incrementable.hpp> |
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17 # include <boost/iterator/iterator_traits.hpp> |
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18 # include <boost/type_traits/add_const.hpp> |
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19 # include <boost/type_traits/remove_cv.hpp> |
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20 # include <boost/mpl/if.hpp> |
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21 # include <boost/mpl/eval_if.hpp> |
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22 |
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23 namespace boost { |
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24 |
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25 namespace detail |
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26 { |
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27 template <class P> |
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28 struct smart_ptr_pointee |
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29 { |
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30 typedef typename P::element_type type; |
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31 }; |
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32 |
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33 template <class Iterator> |
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34 struct iterator_pointee |
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35 { |
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36 typedef typename iterator_traits<Iterator>::value_type value_type; |
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37 |
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38 struct impl |
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39 { |
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40 template <class T> |
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41 static char test(T const&); |
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42 |
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43 static char (& test(value_type&) )[2]; |
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44 |
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45 static Iterator& x; |
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46 }; |
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47 |
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48 BOOST_STATIC_CONSTANT(bool, is_constant = sizeof(impl::test(*impl::x)) == 1); |
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49 |
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50 typedef typename mpl::if_c< |
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51 # if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551)) |
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52 ::boost::detail::iterator_pointee<Iterator>::is_constant |
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53 # else |
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54 is_constant |
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55 # endif |
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56 , typename add_const<value_type>::type |
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57 , value_type |
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58 >::type type; |
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59 }; |
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60 } |
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61 |
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62 template <class P> |
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63 struct pointee |
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64 : mpl::eval_if< |
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65 detail::is_incrementable<P> |
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66 , detail::iterator_pointee<P> |
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67 , detail::smart_ptr_pointee<P> |
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68 > |
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69 { |
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70 }; |
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71 |
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72 } // namespace boost |
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73 |
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74 #endif // POINTEE_DWA200415_HPP |