138 lines
4.0 KiB
Plaintext
138 lines
4.0 KiB
Plaintext
// (C) Copyright David Abrahams 2002.
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// (C) Copyright Jeremy Siek 2002.
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// (C) Copyright Thomas Witt 2002.
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_FILTER_ITERATOR_23022003THW_HPP
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#define BOOST_FILTER_ITERATOR_23022003THW_HPP
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#include <boost/iterator.hpp>
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#include <boost/iterator/iterator_adaptor.hpp>
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#include <boost/iterator/iterator_categories.hpp>
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#include <boost/type_traits/is_class.hpp>
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#include <boost/static_assert.hpp>
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namespace boost {
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namespace iterators {
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template <class Predicate, class Iterator>
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class filter_iterator;
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namespace detail
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{
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template <class Predicate, class Iterator>
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struct filter_iterator_base
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{
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typedef iterator_adaptor<
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filter_iterator<Predicate, Iterator>
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, Iterator
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, use_default
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, typename mpl::if_<
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is_convertible<
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typename iterator_traversal<Iterator>::type
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, random_access_traversal_tag
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>
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, bidirectional_traversal_tag
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, use_default
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>::type
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> type;
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};
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}
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template <class Predicate, class Iterator>
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class filter_iterator
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: public detail::filter_iterator_base<Predicate, Iterator>::type
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{
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typedef typename detail::filter_iterator_base<
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Predicate, Iterator
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>::type super_t;
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friend class iterator_core_access;
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public:
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filter_iterator() { }
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filter_iterator(Predicate f, Iterator x, Iterator end_ = Iterator())
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: super_t(x), m_predicate(f), m_end(end_)
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{
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satisfy_predicate();
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}
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filter_iterator(Iterator x, Iterator end_ = Iterator())
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: super_t(x), m_predicate(), m_end(end_)
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{
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// Pro8 is a little too aggressive about instantiating the
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// body of this function.
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#if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
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// Don't allow use of this constructor if Predicate is a
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// function pointer type, since it will be 0.
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BOOST_STATIC_ASSERT(is_class<Predicate>::value);
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#endif
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satisfy_predicate();
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}
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template<class OtherIterator>
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filter_iterator(
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filter_iterator<Predicate, OtherIterator> const& t
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, typename enable_if_convertible<OtherIterator, Iterator>::type* = 0
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)
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: super_t(t.base()), m_predicate(t.predicate()), m_end(t.end()) {}
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Predicate predicate() const { return m_predicate; }
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Iterator end() const { return m_end; }
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private:
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void increment()
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{
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++(this->base_reference());
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satisfy_predicate();
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}
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void decrement()
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{
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while(!this->m_predicate(*--(this->base_reference()))){};
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}
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void satisfy_predicate()
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{
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while (this->base() != this->m_end && !this->m_predicate(*this->base()))
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++(this->base_reference());
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}
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// Probably should be the initial base class so it can be
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// optimized away via EBO if it is an empty class.
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Predicate m_predicate;
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Iterator m_end;
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};
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template <class Predicate, class Iterator>
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inline filter_iterator<Predicate,Iterator>
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make_filter_iterator(Predicate f, Iterator x, Iterator end = Iterator())
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{
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return filter_iterator<Predicate,Iterator>(f,x,end);
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}
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template <class Predicate, class Iterator>
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inline filter_iterator<Predicate,Iterator>
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make_filter_iterator(
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typename iterators::enable_if<
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is_class<Predicate>
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, Iterator
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>::type x
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, Iterator end = Iterator())
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{
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return filter_iterator<Predicate,Iterator>(x,end);
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}
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} // namespace iterators
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using iterators::filter_iterator;
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using iterators::make_filter_iterator;
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} // namespace boost
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#endif // BOOST_FILTER_ITERATOR_23022003THW_HPP
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