| // (C) Copyright David Abrahams 2002. |
| // (C) Copyright Jeremy Siek 2002. |
| // (C) Copyright Thomas Witt 2002. |
| // 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_FILTER_ITERATOR_23022003THW_HPP |
| #define BOOST_FILTER_ITERATOR_23022003THW_HPP |
| |
| #include <boost/iterator.hpp> |
| #include <boost/iterator/iterator_adaptor.hpp> |
| #include <boost/iterator/iterator_categories.hpp> |
| |
| #include <boost/type_traits/is_class.hpp> |
| #include <boost/static_assert.hpp> |
| |
| namespace boost |
| { |
| template <class Predicate, class Iterator> |
| class filter_iterator; |
| |
| namespace detail |
| { |
| template <class Predicate, class Iterator> |
| struct filter_iterator_base |
| { |
| typedef iterator_adaptor< |
| filter_iterator<Predicate, Iterator> |
| , Iterator |
| , use_default |
| , typename mpl::if_< |
| is_convertible< |
| typename iterator_traversal<Iterator>::type |
| , random_access_traversal_tag |
| > |
| , bidirectional_traversal_tag |
| , use_default |
| >::type |
| > type; |
| }; |
| } |
| |
| template <class Predicate, class Iterator> |
| class filter_iterator |
| : public detail::filter_iterator_base<Predicate, Iterator>::type |
| { |
| typedef typename detail::filter_iterator_base< |
| Predicate, Iterator |
| >::type super_t; |
| |
| friend class iterator_core_access; |
| |
| public: |
| filter_iterator() { } |
| |
| filter_iterator(Predicate f, Iterator x, Iterator end_ = Iterator()) |
| : super_t(x), m_predicate(f), m_end(end_) |
| { |
| satisfy_predicate(); |
| } |
| |
| filter_iterator(Iterator x, Iterator end_ = Iterator()) |
| : super_t(x), m_predicate(), m_end(end_) |
| { |
| // Pro8 is a little too aggressive about instantiating the |
| // body of this function. |
| #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) |
| // Don't allow use of this constructor if Predicate is a |
| // function pointer type, since it will be 0. |
| BOOST_STATIC_ASSERT(is_class<Predicate>::value); |
| #endif |
| satisfy_predicate(); |
| } |
| |
| template<class OtherIterator> |
| filter_iterator( |
| filter_iterator<Predicate, OtherIterator> const& t |
| , typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 |
| ) |
| : super_t(t.base()), m_predicate(t.predicate()), m_end(t.end()) {} |
| |
| Predicate predicate() const { return m_predicate; } |
| |
| Iterator end() const { return m_end; } |
| |
| private: |
| void increment() |
| { |
| ++(this->base_reference()); |
| satisfy_predicate(); |
| } |
| |
| void decrement() |
| { |
| while(!this->m_predicate(*--(this->base_reference()))){}; |
| } |
| |
| void satisfy_predicate() |
| { |
| while (this->base() != this->m_end && !this->m_predicate(*this->base())) |
| ++(this->base_reference()); |
| } |
| |
| // Probably should be the initial base class so it can be |
| // optimized away via EBO if it is an empty class. |
| Predicate m_predicate; |
| Iterator m_end; |
| }; |
| |
| template <class Predicate, class Iterator> |
| filter_iterator<Predicate,Iterator> |
| make_filter_iterator(Predicate f, Iterator x, Iterator end = Iterator()) |
| { |
| return filter_iterator<Predicate,Iterator>(f,x,end); |
| } |
| |
| template <class Predicate, class Iterator> |
| filter_iterator<Predicate,Iterator> |
| make_filter_iterator( |
| typename iterators::enable_if< |
| is_class<Predicate> |
| , Iterator |
| >::type x |
| , Iterator end = Iterator() |
| #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) |
| , Predicate* = 0 |
| #endif |
| ) |
| { |
| return filter_iterator<Predicate,Iterator>(x,end); |
| } |
| |
| } // namespace boost |
| |
| #endif // BOOST_FILTER_ITERATOR_23022003THW_HPP |