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- // Boost.Range library
- //
- // Copyright Thorsten Ottosen, Neil Groves 2006 - 2008. Use, modification and
- // distribution is subject to 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)
- //
- // For more information, see http://www.boost.org/libs/range/
- //
- #ifndef BOOST_RANGE_ADAPTOR_FILTERED_HPP
- #define BOOST_RANGE_ADAPTOR_FILTERED_HPP
- #include <boost/range/adaptor/argument_fwd.hpp>
- #include <boost/range/detail/default_constructible_unary_fn.hpp>
- #include <boost/range/iterator_range.hpp>
- #include <boost/range/concepts.hpp>
- #include <boost/iterator/filter_iterator.hpp>
- namespace boost
- {
- namespace range_detail
- {
- template< class P, class R >
- struct filtered_range :
- boost::iterator_range<
- boost::filter_iterator<
- typename default_constructible_unary_fn_gen<P, bool>::type,
- typename range_iterator<R>::type
- >
- >
- {
- private:
- typedef boost::iterator_range<
- boost::filter_iterator<
- typename default_constructible_unary_fn_gen<P, bool>::type,
- typename range_iterator<R>::type
- >
- > base;
- public:
- typedef typename default_constructible_unary_fn_gen<P, bool>::type
- pred_t;
- filtered_range(P p, R& r)
- : base(make_filter_iterator(pred_t(p),
- boost::begin(r), boost::end(r)),
- make_filter_iterator(pred_t(p),
- boost::end(r), boost::end(r)))
- { }
- };
- template< class T >
- struct filter_holder : holder<T>
- {
- filter_holder( T r ) : holder<T>(r)
- { }
- };
- template< class SinglePassRange, class Predicate >
- inline filtered_range<Predicate, SinglePassRange>
- operator|(SinglePassRange& r,
- const filter_holder<Predicate>& f)
- {
- BOOST_RANGE_CONCEPT_ASSERT((SinglePassRangeConcept<SinglePassRange>));
- return filtered_range<Predicate, SinglePassRange>( f.val, r );
- }
- template< class SinglePassRange, class Predicate >
- inline filtered_range<Predicate, const SinglePassRange>
- operator|(const SinglePassRange& r,
- const filter_holder<Predicate>& f )
- {
- BOOST_RANGE_CONCEPT_ASSERT((
- SinglePassRangeConcept<const SinglePassRange>));
- return filtered_range<Predicate, const SinglePassRange>( f.val, r );
- }
- } // 'range_detail'
- // Unusual use of 'using' is intended to bring filter_range into the boost namespace
- // while leaving the mechanics of the '|' operator in range_detail and maintain
- // argument dependent lookup.
- // filter_range logically needs to be in the boost namespace to allow user of
- // the library to define the return type for filter()
- using range_detail::filtered_range;
- namespace adaptors
- {
- namespace
- {
- const range_detail::forwarder<range_detail::filter_holder>
- filtered =
- range_detail::forwarder<range_detail::filter_holder>();
- }
- template<class SinglePassRange, class Predicate>
- inline filtered_range<Predicate, SinglePassRange>
- filter(SinglePassRange& rng, Predicate filter_pred)
- {
- BOOST_RANGE_CONCEPT_ASSERT((
- SinglePassRangeConcept<SinglePassRange>));
- return range_detail::filtered_range<
- Predicate, SinglePassRange>( filter_pred, rng );
- }
- template<class SinglePassRange, class Predicate>
- inline filtered_range<Predicate, const SinglePassRange>
- filter(const SinglePassRange& rng, Predicate filter_pred)
- {
- BOOST_RANGE_CONCEPT_ASSERT((
- SinglePassRangeConcept<const SinglePassRange>));
- return range_detail::filtered_range<
- Predicate, const SinglePassRange>( filter_pred, rng );
- }
- } // 'adaptors'
- }
- #endif
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