| // Boost.Range library |
| // |
| // 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) |
| // |
| // |
| // 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/utility.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 |
| , typename Reference = typename iterator_reference<Iterator1>::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 |