[857] | 1 | // Copyright David Abrahams 2003. Use, modification and distribution is
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| 2 | // subject to the Boost Software License, Version 1.0. (See accompanying
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| 3 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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| 4 | #ifndef IS_READABLE_ITERATOR_DWA2003112_HPP
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| 5 | # define IS_READABLE_ITERATOR_DWA2003112_HPP
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| 6 |
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| 7 | #include <boost/mpl/bool.hpp>
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| 8 | #include <boost/detail/iterator.hpp>
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| 9 |
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| 10 | #include <boost/type_traits/detail/bool_trait_def.hpp>
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| 11 | #include <boost/iterator/detail/any_conversion_eater.hpp>
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| 12 |
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| 13 | // should be the last #include
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| 14 | #include <boost/iterator/detail/config_def.hpp>
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| 15 |
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| 16 | #ifndef BOOST_NO_IS_CONVERTIBLE
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| 17 |
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| 18 | namespace boost {
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| 19 |
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| 20 | namespace detail
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| 21 | {
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| 22 | // Guts of is_readable_iterator. Value is the iterator's value_type
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| 23 | // and the result is computed in the nested rebind template.
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| 24 | template <class Value>
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| 25 | struct is_readable_iterator_impl
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| 26 | {
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| 27 | static char tester(Value&, int);
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| 28 | static char (& tester(any_conversion_eater, ...) )[2];
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| 29 |
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| 30 | template <class It>
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| 31 | struct rebind
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| 32 | {
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| 33 | static It& x;
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| 34 |
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| 35 | BOOST_STATIC_CONSTANT(
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| 36 | bool
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| 37 | , value = (
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| 38 | sizeof(
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| 39 | is_readable_iterator_impl<Value>::tester(*x, 1)
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| 40 | ) == 1
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| 41 | )
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| 42 | );
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| 43 | };
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| 44 | };
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| 45 |
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| 46 | #undef BOOST_READABLE_PRESERVER
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| 47 |
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| 48 | //
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| 49 | // void specializations to handle std input and output iterators
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| 50 | //
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| 51 | template <>
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| 52 | struct is_readable_iterator_impl<void>
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| 53 | {
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| 54 | template <class It>
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| 55 | struct rebind : boost::mpl::false_
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| 56 | {};
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| 57 | };
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| 58 |
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| 59 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
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| 60 | template <>
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| 61 | struct is_readable_iterator_impl<const void>
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| 62 | {
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| 63 | template <class It>
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| 64 | struct rebind : boost::mpl::false_
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| 65 | {};
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| 66 | };
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| 67 |
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| 68 | template <>
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| 69 | struct is_readable_iterator_impl<volatile void>
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| 70 | {
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| 71 | template <class It>
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| 72 | struct rebind : boost::mpl::false_
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| 73 | {};
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| 74 | };
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| 75 |
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| 76 | template <>
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| 77 | struct is_readable_iterator_impl<const volatile void>
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| 78 | {
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| 79 | template <class It>
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| 80 | struct rebind : boost::mpl::false_
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| 81 | {};
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| 82 | };
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| 83 | #endif
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| 84 |
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| 85 | //
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| 86 | // This level of dispatching is required for Borland. We might save
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| 87 | // an instantiation by removing it for others.
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| 88 | //
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| 89 | template <class It>
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| 90 | struct is_readable_iterator_impl2
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| 91 | : is_readable_iterator_impl<
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| 92 | BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<It>::value_type const
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| 93 | >::template rebind<It>
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| 94 | {};
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| 95 | } // namespace detail
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| 96 |
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| 97 | // Define the trait with full mpl lambda capability and various broken
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| 98 | // compiler workarounds
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| 99 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(
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| 100 | is_readable_iterator,T,::boost::detail::is_readable_iterator_impl2<T>::value)
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| 101 |
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| 102 | } // namespace boost
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| 103 |
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| 104 | #endif
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| 105 |
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| 106 | #include <boost/iterator/detail/config_undef.hpp>
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| 107 |
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| 108 | #endif // IS_READABLE_ITERATOR_DWA2003112_HPP
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