// (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 |