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- // (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/iterator_adaptor.hpp>
- #include <boost/iterator/iterator_categories.hpp>
- #include <boost/type_traits/is_class.hpp>
- #include <boost/static_assert.hpp>
- namespace boost {
- namespace iterators {
- 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>
- inline 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>
- inline filter_iterator<Predicate,Iterator>
- make_filter_iterator(
- typename iterators::enable_if<
- is_class<Predicate>
- , Iterator
- >::type x
- , Iterator end = Iterator())
- {
- return filter_iterator<Predicate,Iterator>(x,end);
- }
- } // namespace iterators
- using iterators::filter_iterator;
- using iterators::make_filter_iterator;
- } // namespace boost
- #endif // BOOST_FILTER_ITERATOR_23022003THW_HPP
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