/usr/include/boost/range/detail/join_iterator.hpp is in libboost1.55-dev 1.55.0+dfsg-3.
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//
// Copyright Neil Groves 2009. Use, modification and
// distribution is subject to 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)
//
// Acknowledgements:
// aschoedl contributed an improvement to the determination
// of the Reference type parameter.
//
// For more information, see http://www.boost.org/libs/range/
//
#ifndef BOOST_RANGE_DETAIL_JOIN_ITERATOR_HPP_INCLUDED
#define BOOST_RANGE_DETAIL_JOIN_ITERATOR_HPP_INCLUDED
#include <iterator>
#include <boost/assert.hpp>
#include <boost/iterator/iterator_traits.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/empty.hpp>
#include <boost/range/detail/demote_iterator_traversal_tag.hpp>
#include <boost/range/value_type.hpp>
#include <boost/next_prior.hpp>
namespace boost
{
namespace range_detail
{
template<typename Iterator1, typename Iterator2>
struct join_iterator_link
{
public:
join_iterator_link(Iterator1 last1, Iterator2 first2)
: last1(last1)
, first2(first2)
{
}
Iterator1 last1;
Iterator2 first2;
private:
join_iterator_link() /* = delete */ ;
};
class join_iterator_begin_tag {};
class join_iterator_end_tag {};
template<typename Iterator1
, typename Iterator2
, typename Reference
>
class join_iterator_union
{
public:
typedef Iterator1 iterator1_t;
typedef Iterator2 iterator2_t;
join_iterator_union() {}
join_iterator_union(unsigned int /*selected*/, const iterator1_t& it1, const iterator2_t& it2) : m_it1(it1), m_it2(it2) {}
iterator1_t& it1() { return m_it1; }
const iterator1_t& it1() const { return m_it1; }
iterator2_t& it2() { return m_it2; }
const iterator2_t& it2() const { return m_it2; }
Reference dereference(unsigned int selected) const
{
return selected ? *m_it2 : *m_it1;
}
bool equal(const join_iterator_union& other, unsigned int selected) const
{
return selected
? m_it2 == other.m_it2
: m_it1 == other.m_it1;
}
private:
iterator1_t m_it1;
iterator2_t m_it2;
};
template<class Iterator, class Reference>
class join_iterator_union<Iterator, Iterator, Reference>
{
public:
typedef Iterator iterator1_t;
typedef Iterator iterator2_t;
join_iterator_union() {}
join_iterator_union(unsigned int selected, const iterator1_t& it1, const iterator2_t& it2)
: m_it(selected ? it2 : it1)
{
}
iterator1_t& it1() { return m_it; }
const iterator1_t& it1() const { return m_it; }
iterator2_t& it2() { return m_it; }
const iterator2_t& it2() const { return m_it; }
Reference dereference(unsigned int) const
{
return *m_it;
}
bool equal(const join_iterator_union& other, unsigned int selected) const
{
return m_it == other.m_it;
}
private:
iterator1_t m_it;
};
template<typename Iterator1
, typename Iterator2
, typename ValueType = typename iterator_value<Iterator1>::type
// find least demanding, commonly supported reference type, in the order &, const&, and by-value:
, typename Reference = typename mpl::if_c<
!is_reference<typename iterator_reference<Iterator1>::type>::value
|| !is_reference<typename iterator_reference<Iterator2>::type>::value,
typename remove_const<
typename remove_reference<
typename iterator_reference<Iterator1>::type
>::type
>::type,
typename mpl::if_c<
is_const<
typename remove_reference<
typename iterator_reference<Iterator1>::type
>::type
>::value
|| is_const<
typename remove_reference<
typename iterator_reference<Iterator2>::type
>::type
>::value,
typename add_const<
typename iterator_reference<Iterator2>::type
>::type,
typename iterator_reference<Iterator1>::type
>::type
>::type
, typename Traversal = typename demote_iterator_traversal_tag<
typename iterator_traversal<Iterator1>::type
, typename iterator_traversal<Iterator2>::type>::type
>
class join_iterator
: public iterator_facade<join_iterator<Iterator1,Iterator2,ValueType,Reference,Traversal>, ValueType, Traversal, Reference>
{
typedef join_iterator_link<Iterator1, Iterator2> link_t;
typedef join_iterator_union<Iterator1, Iterator2, Reference> iterator_union;
public:
typedef Iterator1 iterator1_t;
typedef Iterator2 iterator2_t;
join_iterator()
: m_section(0u)
, m_it(0u, iterator1_t(), iterator2_t())
, m_link(link_t(iterator1_t(), iterator2_t()))
{}
join_iterator(unsigned int section, Iterator1 current1, Iterator1 last1, Iterator2 first2, Iterator2 current2)
: m_section(section)
, m_it(section, current1, current2)
, m_link(link_t(last1, first2))
{
}
template<typename Range1, typename Range2>
join_iterator(Range1& r1, Range2& r2, join_iterator_begin_tag)
: m_section(boost::empty(r1) ? 1u : 0u)
, m_it(boost::empty(r1) ? 1u : 0u, boost::begin(r1), boost::begin(r2))
, m_link(link_t(boost::end(r1), boost::begin(r2)))
{
}
template<typename Range1, typename Range2>
join_iterator(const Range1& r1, const Range2& r2, join_iterator_begin_tag)
: m_section(boost::empty(r1) ? 1u : 0u)
, m_it(boost::empty(r1) ? 1u : 0u, boost::const_begin(r1), boost::const_begin(r2))
, m_link(link_t(boost::const_end(r1), boost::const_begin(r2)))
{
}
template<typename Range1, typename Range2>
join_iterator(Range1& r1, Range2& r2, join_iterator_end_tag)
: m_section(1u)
, m_it(1u, boost::end(r1), boost::end(r2))
, m_link(link_t(boost::end(r1), boost::begin(r2)))
{
}
template<typename Range1, typename Range2>
join_iterator(const Range1& r1, const Range2& r2, join_iterator_end_tag)
: m_section(1u)
, m_it(1u, boost::const_end(r1), boost::const_end(r2))
, m_link(link_t(boost::const_end(r1), boost::const_begin(r2)))
{
}
private:
void increment()
{
if (m_section)
++m_it.it2();
else
{
++m_it.it1();
if (m_it.it1() == m_link.last1)
{
m_it.it2() = m_link.first2;
m_section = 1u;
}
}
}
void decrement()
{
if (m_section)
{
if (m_it.it2() == m_link.first2)
{
m_it.it1() = boost::prior(m_link.last1);
m_section = 0u;
}
else
--m_it.it2();
}
else
--m_it.it1();
}
typename join_iterator::reference dereference() const
{
return m_it.dereference(m_section);
}
bool equal(const join_iterator& other) const
{
return m_section == other.m_section
&& m_it.equal(other.m_it, m_section);
}
void advance(typename join_iterator::difference_type offset)
{
if (m_section)
advance_from_range2(offset);
else
advance_from_range1(offset);
}
typename join_iterator::difference_type distance_to(const join_iterator& other) const
{
typename join_iterator::difference_type result;
if (m_section)
{
if (other.m_section)
result = other.m_it.it2() - m_it.it2();
else
{
result = (m_link.first2 - m_it.it2())
+ (other.m_it.it1() - m_link.last1);
BOOST_ASSERT( result <= 0 );
}
}
else
{
if (other.m_section)
{
result = (m_link.last1 - m_it.it1())
+ (other.m_it.it2() - m_link.first2);
}
else
result = other.m_it.it1() - m_it.it1();
}
return result;
}
void advance_from_range2(typename join_iterator::difference_type offset)
{
typedef typename join_iterator::difference_type difference_t;
BOOST_ASSERT( m_section == 1u );
if (offset < 0)
{
difference_t r2_dist = m_link.first2 - m_it.it2();
BOOST_ASSERT( r2_dist <= 0 );
if (offset >= r2_dist)
std::advance(m_it.it2(), offset);
else
{
difference_t r1_dist = offset - r2_dist;
BOOST_ASSERT( r1_dist <= 0 );
m_it.it1() = m_link.last1 + r1_dist;
m_section = 0u;
}
}
else
std::advance(m_it.it2(), offset);
}
void advance_from_range1(typename join_iterator::difference_type offset)
{
typedef typename join_iterator::difference_type difference_t;
BOOST_ASSERT( m_section == 0u );
if (offset > 0)
{
difference_t r1_dist = m_link.last1 - m_it.it1();
BOOST_ASSERT( r1_dist >= 0 );
if (offset < r1_dist)
std::advance(m_it.it1(), offset);
else
{
difference_t r2_dist = offset - r1_dist;
BOOST_ASSERT( r2_dist >= 0 );
m_it.it2() = m_link.first2 + r2_dist;
m_section = 1u;
}
}
else
std::advance(m_it.it1(), offset);
}
unsigned int m_section;
iterator_union m_it;
link_t m_link;
friend class ::boost::iterator_core_access;
};
} // namespace range_detail
} // namespace boost
#endif // include guard
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