Chris@102: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@102: 
Chris@102: // Copyright (c) 2014, Oracle and/or its affiliates.
Chris@102: 
Chris@102: // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
Chris@102: 
Chris@102: // Licensed under the Boost Software License version 1.0.
Chris@102: // http://www.boost.org/users/license.html
Chris@102: 
Chris@102: #ifndef BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
Chris@102: #define BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
Chris@102: 
Chris@102: #include <boost/assert.hpp>
Chris@102: #include <boost/mpl/assert.hpp>
Chris@102: #include <boost/type_traits/is_convertible.hpp>
Chris@102: #include <boost/iterator.hpp>
Chris@102: #include <boost/iterator/iterator_facade.hpp>
Chris@102: #include <boost/iterator/iterator_categories.hpp>
Chris@102: 
Chris@102: 
Chris@102: namespace boost { namespace geometry
Chris@102: {
Chris@102: 
Chris@102: 
Chris@102: 
Chris@102: template
Chris@102: <
Chris@102:     typename OuterIterator,
Chris@102:     typename InnerIterator,
Chris@102:     typename Value,
Chris@102:     typename AccessInnerBegin,
Chris@102:     typename AccessInnerEnd,
Chris@102:     typename Reference = Value&
Chris@102: >
Chris@102: class flatten_iterator
Chris@102:     : public boost::iterator_facade
Chris@102:         <
Chris@102:             flatten_iterator
Chris@102:                 <
Chris@102:                     OuterIterator,
Chris@102:                     InnerIterator,
Chris@102:                     Value,
Chris@102:                     AccessInnerBegin,
Chris@102:                     AccessInnerEnd,
Chris@102:                     Reference
Chris@102:                 >,
Chris@102:             Value,
Chris@102:             boost::bidirectional_traversal_tag,
Chris@102:             Reference
Chris@102:         >
Chris@102: {
Chris@102: private:
Chris@102:     OuterIterator m_outer_it, m_outer_end;
Chris@102:     InnerIterator m_inner_it;
Chris@102: 
Chris@102: public:
Chris@102:     typedef OuterIterator outer_iterator_type;
Chris@102:     typedef InnerIterator inner_iterator_type;
Chris@102: 
Chris@102:     // default constructor
Chris@102:     flatten_iterator() {}
Chris@102: 
Chris@102:     // for begin
Chris@102:     flatten_iterator(OuterIterator outer_it, OuterIterator outer_end)
Chris@102:         : m_outer_it(outer_it), m_outer_end(outer_end)
Chris@102:     {
Chris@102:         advance_through_empty();
Chris@102:     }
Chris@102: 
Chris@102:     // for end
Chris@102:     flatten_iterator(OuterIterator outer_end)
Chris@102:         : m_outer_it(outer_end), m_outer_end(outer_end)
Chris@102:     {}
Chris@102: 
Chris@102:     template
Chris@102:     <
Chris@102:         typename OtherOuterIterator, typename OtherInnerIterator,
Chris@102:         typename OtherValue,
Chris@102:         typename OtherAccessInnerBegin, typename OtherAccessInnerEnd,
Chris@102:         typename OtherReference
Chris@102:     >
Chris@102:     flatten_iterator(flatten_iterator
Chris@102:                      <
Chris@102:                          OtherOuterIterator,
Chris@102:                          OtherInnerIterator,
Chris@102:                          OtherValue,
Chris@102:                          OtherAccessInnerBegin,
Chris@102:                          OtherAccessInnerEnd,
Chris@102:                          OtherReference
Chris@102:                      > const& other)
Chris@102:         : m_outer_it(other.m_outer_it),
Chris@102:           m_outer_end(other.m_outer_end),
Chris@102:           m_inner_it(other.m_inner_it)
Chris@102:     {
Chris@102:         static const bool are_conv
Chris@102:             = boost::is_convertible
Chris@102:                 <
Chris@102:                     OtherOuterIterator, OuterIterator
Chris@102:                 >::value
Chris@102:            && boost::is_convertible
Chris@102:                 <
Chris@102:                     OtherInnerIterator, InnerIterator
Chris@102:                 >::value;
Chris@102: 
Chris@102:         BOOST_MPL_ASSERT_MSG((are_conv),
Chris@102:                              NOT_CONVERTIBLE,
Chris@102:                              (types<OtherOuterIterator, OtherInnerIterator>));
Chris@102:     }
Chris@102: 
Chris@102:     flatten_iterator& operator=(flatten_iterator const& other)
Chris@102:     {
Chris@102:         m_outer_it = other.m_outer_it;
Chris@102:         m_outer_end = other.m_outer_end;
Chris@102:         // avoid assigning an iterator having singular value
Chris@102:         if ( other.m_outer_it != other.m_outer_end )
Chris@102:         {
Chris@102:             m_inner_it = other.m_inner_it;
Chris@102:         }
Chris@102:         return *this;
Chris@102:     }
Chris@102: 
Chris@102: private:
Chris@102:     friend class boost::iterator_core_access;
Chris@102: 
Chris@102:     template
Chris@102:     <
Chris@102:         typename Outer,
Chris@102:         typename Inner,
Chris@102:         typename V,
Chris@102:         typename InnerBegin,
Chris@102:         typename InnerEnd,
Chris@102:         typename R
Chris@102:     >
Chris@102:     friend class flatten_iterator;
Chris@102: 
Chris@102:     static inline bool empty(OuterIterator outer_it)
Chris@102:     {
Chris@102:         return AccessInnerBegin::apply(*outer_it)
Chris@102:             == AccessInnerEnd::apply(*outer_it);
Chris@102:     }
Chris@102: 
Chris@102:     inline void advance_through_empty()
Chris@102:     {
Chris@102:         while ( m_outer_it != m_outer_end && empty(m_outer_it) )
Chris@102:         {
Chris@102:             ++m_outer_it;
Chris@102:         }
Chris@102: 
Chris@102:         if ( m_outer_it != m_outer_end )
Chris@102:         {
Chris@102:             m_inner_it = AccessInnerBegin::apply(*m_outer_it);
Chris@102:         }
Chris@102:     }
Chris@102: 
Chris@102:     inline Reference dereference() const
Chris@102:     {
Chris@102:         BOOST_ASSERT( m_outer_it != m_outer_end );
Chris@102:         BOOST_ASSERT( m_inner_it != AccessInnerEnd::apply(*m_outer_it) );
Chris@102:         return *m_inner_it;
Chris@102:     }
Chris@102: 
Chris@102: 
Chris@102:     template
Chris@102:     <
Chris@102:         typename OtherOuterIterator,
Chris@102:         typename OtherInnerIterator,
Chris@102:         typename OtherValue,
Chris@102:         typename OtherAccessInnerBegin,
Chris@102:         typename OtherAccessInnerEnd,
Chris@102:         typename OtherReference
Chris@102:     >
Chris@102:     inline bool equal(flatten_iterator
Chris@102:                       <
Chris@102:                           OtherOuterIterator,
Chris@102:                           OtherInnerIterator,
Chris@102:                           OtherValue,
Chris@102:                           OtherAccessInnerBegin,
Chris@102:                           OtherAccessInnerEnd,
Chris@102:                           OtherReference
Chris@102:                       > const& other) const
Chris@102:     {
Chris@102:         if ( m_outer_it != other.m_outer_it )
Chris@102:         {
Chris@102:             return false;
Chris@102:         }
Chris@102: 
Chris@102:         if ( m_outer_it == m_outer_end )
Chris@102:         {
Chris@102:             return true;
Chris@102:         }
Chris@102: 
Chris@102:         return m_inner_it == other.m_inner_it;
Chris@102:     }
Chris@102: 
Chris@102:     inline void increment()
Chris@102:     {
Chris@102:         BOOST_ASSERT( m_outer_it != m_outer_end );
Chris@102:         BOOST_ASSERT( m_inner_it != AccessInnerEnd::apply(*m_outer_it) );
Chris@102: 
Chris@102:         ++m_inner_it;
Chris@102:         if ( m_inner_it == AccessInnerEnd::apply(*m_outer_it) )
Chris@102:         {
Chris@102:             ++m_outer_it;
Chris@102:             advance_through_empty();
Chris@102:         }
Chris@102:     }
Chris@102: 
Chris@102:     inline void decrement()
Chris@102:     {
Chris@102:         if ( m_outer_it == m_outer_end
Chris@102:              || m_inner_it == AccessInnerBegin::apply(*m_outer_it) )
Chris@102:         {
Chris@102:             do
Chris@102:             {
Chris@102:                 --m_outer_it;
Chris@102:             }
Chris@102:             while ( empty(m_outer_it) );
Chris@102:             m_inner_it = --AccessInnerEnd::apply(*m_outer_it);
Chris@102:         }
Chris@102:         else
Chris@102:         {
Chris@102:             --m_inner_it;
Chris@102:         }
Chris@102:     }
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: 
Chris@102: }} // namespace boost::geometry
Chris@102: 
Chris@102: 
Chris@102: #endif // BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP