source: downloads/boost_1_33_1/libs/iterator/test/unit_tests.cpp @ 13

// Copyright David Abrahams 2003.
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#include <boost/iterator/iterator_adaptor.hpp>
#include <boost/static_assert.hpp>

#include "static_assert_same.hpp"

#include <boost/type_traits/broken_compiler_spec.hpp>

#include <boost/iterator/detail/minimum_category.hpp>

struct X { int a; };

BOOST_TT_BROKEN_COMPILER_SPEC(X)

struct Xiter : boost::iterator_adaptor<Xiter,X*>
{
    Xiter();
    Xiter(X* p) : boost::iterator_adaptor<Xiter, X*>(p) {}
};

void take_xptr(X*) {}
void operator_arrow_test()
{
    // check that the operator-> result is a pointer for lvalue iterators
    X x;
    take_xptr(Xiter(&x).operator->());
}

template <class T, class U, class Min>
struct static_assert_min_cat
  : static_assert_same<
       typename boost::detail::minimum_category<T,U>::type, Min
    >
{};

void category_test()
{
    using namespace boost;
    using namespace boost::detail;
    
    BOOST_STATIC_ASSERT((
        !boost::is_convertible<
            std::input_iterator_tag
          , input_output_iterator_tag>::value));
    
    BOOST_STATIC_ASSERT((
        !boost::is_convertible<
            std::output_iterator_tag
          , input_output_iterator_tag>::value));
    
    BOOST_STATIC_ASSERT((
        boost::is_convertible<
            input_output_iterator_tag
          , std::input_iterator_tag>::value));
    
    BOOST_STATIC_ASSERT((
        boost::is_convertible<
            input_output_iterator_tag
          , std::output_iterator_tag>::value));

#if 0 // This seems wrong; we're not advertising
      // input_output_iterator_tag are we?
    BOOST_STATIC_ASSERT((
        boost::is_convertible<
            std::forward_iterator_tag
          , input_output_iterator_tag>::value));
#endif 

    int test = static_assert_min_cat<
        std::input_iterator_tag,input_output_iterator_tag, std::input_iterator_tag
    >::value;

    test = static_assert_min_cat<
        input_output_iterator_tag,std::input_iterator_tag, std::input_iterator_tag
    >::value;

#if 0
    test = static_assert_min_cat<
        input_output_iterator_tag,std::forward_iterator_tag, input_output_iterator_tag
    >::value;
#endif 

    test = static_assert_min_cat<
        std::input_iterator_tag,std::forward_iterator_tag, std::input_iterator_tag
    >::value;

    test = static_assert_min_cat<
        std::input_iterator_tag,std::random_access_iterator_tag, std::input_iterator_tag
    >::value;

#if 0  // This would be wrong: a random access iterator is not
       // neccessarily writable, as is an output iterator.
    test = static_assert_min_cat<
        std::output_iterator_tag,std::random_access_iterator_tag, std::output_iterator_tag
    >::value;
#endif 
    
    (void)test;
}

int main()
{
    category_test();
    operator_arrow_test();
    return 0;
}