boost/intrusive/detail/iterator.hpp
/////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2014-2014
//
// 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)
//
// See http://www.boost.org/libs/intrusive for documentation.
//
/////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTRUSIVE_DETAIL_ITERATOR_HPP
#define BOOST_INTRUSIVE_DETAIL_ITERATOR_HPP
#ifndef BOOST_CONFIG_HPP
# include <boost/config.hpp>
#endif
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif
#include <cstddef>
#include <boost/intrusive/detail/std_fwd.hpp>
#include <boost/move/detail/iterator_traits.hpp>
#include <boost/move/detail/meta_utils_core.hpp>
namespace boost {
namespace intrusive {
using boost::movelib::iterator_traits;
////////////////////
// iterator
////////////////////
template<class Category, class T, class Distance, class Pointer = T*, class Reference = T&>
struct iterator
{
typedef Category iterator_category;
typedef T value_type;
typedef Distance difference_type;
typedef Pointer pointer;
typedef Reference reference;
};
////////////////////////////////////////
// iterator_[dis|en]able_if_tag
////////////////////////////////////////
template<class I, class Tag, class R = void>
struct iterator_enable_if_tag
: ::boost::move_detail::enable_if_c
< ::boost::move_detail::is_same
< typename boost::intrusive::iterator_traits<I>::iterator_category
, Tag
>::value
, R>
{};
template<class I, class Tag, class R = void>
struct iterator_disable_if_tag
: ::boost::move_detail::enable_if_c
< !::boost::move_detail::is_same
< typename boost::intrusive::iterator_traits<I>::iterator_category
, Tag
>::value
, R>
{};
////////////////////////////////////////
// iterator_[dis|en]able_if_tag_difference_type
////////////////////////////////////////
template<class I, class Tag>
struct iterator_enable_if_tag_difference_type
: iterator_enable_if_tag<I, Tag, typename boost::intrusive::iterator_traits<I>::difference_type>
{};
template<class I, class Tag>
struct iterator_disable_if_tag_difference_type
: iterator_disable_if_tag<I, Tag, typename boost::intrusive::iterator_traits<I>::difference_type>
{};
////////////////////
// advance
////////////////////
template<class InputIt, class Distance> inline
typename iterator_enable_if_tag<InputIt, std::input_iterator_tag>::type
iterator_advance(InputIt& it, Distance n)
{
while(n--)
++it;
}
template<class InputIt, class Distance> inline
typename iterator_enable_if_tag<InputIt, std::forward_iterator_tag>::type
iterator_advance(InputIt& it, Distance n)
{
while(n--)
++it;
}
template<class InputIt, class Distance> inline
typename iterator_enable_if_tag<InputIt, std::bidirectional_iterator_tag>::type
iterator_advance(InputIt& it, Distance n)
{
for (; 0 < n; --n)
++it;
for (; n < 0; ++n)
--it;
}
template<class InputIt, class Distance> inline
typename iterator_enable_if_tag<InputIt, std::random_access_iterator_tag>::type
iterator_advance(InputIt& it, Distance n)
{
it += n;
}
////////////////////
// distance
////////////////////
template<class InputIt> inline
typename iterator_disable_if_tag_difference_type
<InputIt, std::random_access_iterator_tag>::type
iterator_distance(InputIt first, InputIt last)
{
typename iterator_traits<InputIt>::difference_type off = 0;
while(first != last){
++off;
++first;
}
return off;
}
template<class InputIt> inline
typename iterator_enable_if_tag_difference_type
<InputIt, std::random_access_iterator_tag>::type
iterator_distance(InputIt first, InputIt last)
{
typename iterator_traits<InputIt>::difference_type off = last - first;
return off;
}
} //namespace intrusive
} //namespace boost
#endif //BOOST_INTRUSIVE_DETAIL_ITERATOR_HPP