forked from boostorg/iterator
75 lines
1.6 KiB
C++
75 lines
1.6 KiB
C++
// Copyright (C) 2017 Michel Morin.
|
|
//
|
|
// 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)
|
|
|
|
#ifndef BOOST_ITERATOR_ADVANCE_HPP
|
|
#define BOOST_ITERATOR_ADVANCE_HPP
|
|
|
|
#include <boost/config.hpp>
|
|
#include <boost/iterator/iterator_categories.hpp>
|
|
|
|
namespace boost {
|
|
namespace iterators {
|
|
namespace detail {
|
|
|
|
template< typename InputIterator, typename Distance >
|
|
inline BOOST_CXX14_CONSTEXPR void advance_impl(InputIterator& it, Distance n, incrementable_traversal_tag)
|
|
{
|
|
while (n > 0)
|
|
{
|
|
++it;
|
|
--n;
|
|
}
|
|
}
|
|
|
|
template< typename BidirectionalIterator, typename Distance >
|
|
inline BOOST_CXX14_CONSTEXPR void advance_impl(BidirectionalIterator& it, Distance n, bidirectional_traversal_tag)
|
|
{
|
|
if (n >= 0)
|
|
{
|
|
while (n > 0)
|
|
{
|
|
++it;
|
|
--n;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
while (n < 0)
|
|
{
|
|
--it;
|
|
++n;
|
|
}
|
|
}
|
|
}
|
|
|
|
template< typename RandomAccessIterator, typename Distance >
|
|
inline BOOST_CXX14_CONSTEXPR void advance_impl(RandomAccessIterator& it, Distance n, random_access_traversal_tag)
|
|
{
|
|
it += n;
|
|
}
|
|
|
|
} // namespace detail
|
|
|
|
namespace advance_adl_barrier {
|
|
|
|
template< typename InputIterator, typename Distance >
|
|
inline BOOST_CXX14_CONSTEXPR void advance(InputIterator& it, Distance n)
|
|
{
|
|
detail::advance_impl(it, n, typename iterator_traversal< InputIterator >::type());
|
|
}
|
|
|
|
} // namespace advance_adl_barrier
|
|
|
|
using namespace advance_adl_barrier;
|
|
|
|
} // namespace iterators
|
|
|
|
using namespace iterators::advance_adl_barrier;
|
|
|
|
} // namespace boost
|
|
|
|
#endif
|