forked from boostorg/detail
Dave Abrahams
9ab05a600a
is_incrementable.hpp: checks whether ++x is well-formed pointee.hpp: value_type of iterators or smart pointers indirect_reference.hpp: reference type of iterators or smart pointers indirect_iterator.hpp indirect_iterator_member_types.cpp Use pointee/indirect_reference to select value/reference type. iterator_concepts.hpp: Fixed interoperable test. Hardly tests enough, but it's a start minimum_category.hpp: Better error messages for vc6 indirect_iterator_test.cpp: Workarounds for compilers without SFINAE static_assert_same.hpp: Informative error reports; added a macro. zip_iterator_test.hpp: Added missing #include Jamfile: made zip_iterator test pass with vc6/stlport [SVN r21514]
72 lines
1.9 KiB
C++
Executable File
72 lines
1.9 KiB
C++
Executable File
// Copyright David Abrahams 2004. Use, modification and distribution is
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// subject to the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef IS_INCREMENTABLE_DWA200415_HPP
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# define IS_INCREMENTABLE_DWA200415_HPP
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# include <boost/type_traits/remove_cv.hpp>
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# include <boost/mpl/bool.hpp>
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# include <boost/detail/workaround.hpp>
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namespace boost { namespace detail {
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// is_incrementable<T> metafunction
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//
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// Requires: Given x of type T&, if the expression ++x is well-formed
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// it must have complete type; otherwise, it must neither be ambiguous
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// nor violate access.
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// This namespace ensures that ADL doesn't mess things up.
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namespace is_incrementable_
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{
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struct tag {};
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// any soaks up implicit conversions and makes the following
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// operator++ less-preferred than any other such operator which
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// might be found via ADL.
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struct any { template <class T> any(T const&); };
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tag operator++(any const&);
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// two check overloads help us identify which operator++ was picked
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char (& check(tag) )[2];
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template <class T>
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char check(T const&);
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template <class T>
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struct
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# if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
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impl
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# else
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is_incrementable
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# endif
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{
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static typename remove_cv<T>::type& x;
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BOOST_STATIC_CONSTANT(
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bool
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, value = sizeof(is_incrementable_::check(++x)) == 1
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);
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typedef mpl::bool_<(
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# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
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::boost::detail::is_incrementable_::is_incrementable<T>::
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# endif
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value)> type;
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};
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}
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# if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
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template <class T>
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struct is_incrementable : is_incrementable_::impl<T>
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{
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};
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# else
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using is_incrementable_::is_incrementable;
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# endif
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}} // namespace boost::detail
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#endif // IS_INCREMENTABLE_DWA200415_HPP
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