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Sprout/sprout/iterator/next.hpp
2012-04-04 17:48:02 +09:00

81 lines
2.5 KiB
C++

#ifndef SPROUT_ITERATOR_NEXT_HPP
#define SPROUT_ITERATOR_NEXT_HPP
#include <iterator>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/utility/forward.hpp>
namespace sprout {
namespace detail {
template<typename RandomAccessIterator>
SPROUT_CONSTEXPR typename std::enable_if<
std::is_literal_type<typename std::decay<RandomAccessIterator>::type>::value,
typename std::decay<RandomAccessIterator>::type
>::type next_impl(
RandomAccessIterator&& it,
std::random_access_iterator_tag*
)
{
return sprout::forward<RandomAccessIterator>(it) + 1;
}
template<typename ForwardIterator>
SPROUT_CONSTEXPR typename std::decay<ForwardIterator>::type next_impl(
ForwardIterator&& it,
void*
)
{
using std::next;
return next(sprout::forward<ForwardIterator>(it));
}
template<typename RandomAccessIterator>
SPROUT_CONSTEXPR typename std::enable_if<
std::is_literal_type<typename std::decay<RandomAccessIterator>::type>::value,
typename std::decay<RandomAccessIterator>::type
>::type next_impl(
RandomAccessIterator&& it,
typename std::iterator_traits<typename std::decay<RandomAccessIterator>::type>::difference_type n,
std::random_access_iterator_tag*
)
{
return sprout::forward<RandomAccessIterator>(it) + n;
}
template<typename ForwardIterator>
SPROUT_CONSTEXPR typename std::decay<ForwardIterator>::type next_impl(
ForwardIterator it,
typename std::iterator_traits<typename std::decay<ForwardIterator>::type>::difference_type n,
void*
)
{
using std::next;
return next(sprout::forward<ForwardIterator>(it), n);
}
} // namespace detail
//
// next
//
template<typename ForwardIterator>
SPROUT_CONSTEXPR typename std::decay<ForwardIterator>::type next(ForwardIterator&& it) {
typedef typename std::iterator_traits<typename std::decay<ForwardIterator>::type>::iterator_category* category;
return sprout::detail::next_impl(
sprout::forward<ForwardIterator>(it),
category()
);
}
template<typename ForwardIterator>
SPROUT_CONSTEXPR typename std::decay<ForwardIterator>::type next(
ForwardIterator&& it,
typename std::iterator_traits<typename std::decay<ForwardIterator>::type>::difference_type n
)
{
typedef typename std::iterator_traits<typename std::decay<ForwardIterator>::type>::iterator_category* category;
return sprout::detail::next_impl(
sprout::forward<ForwardIterator>(it),
n,
category()
);
}
} // namespace sprout
#endif // #ifndef SPROUT_ITERATOR_NEXT_HPP