122 lines
4.3 KiB
Plaintext
122 lines
4.3 KiB
Plaintext
// Boost.Range library
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//
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// Copyright Thorsten Ottosen, Neil Groves 2006 - 2008. Use, modification and
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// distribution is subject to the Boost Software License, Version
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// 1.0. (See 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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//
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// For more information, see http://www.boost.org/libs/range/
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//
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#ifndef BOOST_RANGE_ADAPTOR_FILTERED_HPP
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#define BOOST_RANGE_ADAPTOR_FILTERED_HPP
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#include <boost/range/adaptor/argument_fwd.hpp>
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#include <boost/range/detail/default_constructible_unary_fn.hpp>
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#include <boost/range/iterator_range.hpp>
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#include <boost/range/concepts.hpp>
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#include <boost/iterator/filter_iterator.hpp>
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namespace boost
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{
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namespace range_detail
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{
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template< class P, class R >
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struct filtered_range :
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boost::iterator_range<
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boost::filter_iterator<
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typename default_constructible_unary_fn_gen<P, bool>::type,
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typename range_iterator<R>::type
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>
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>
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{
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private:
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typedef boost::iterator_range<
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boost::filter_iterator<
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typename default_constructible_unary_fn_gen<P, bool>::type,
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typename range_iterator<R>::type
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>
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> base;
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public:
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typedef typename default_constructible_unary_fn_gen<P, bool>::type
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pred_t;
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filtered_range(P p, R& r)
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: base(make_filter_iterator(pred_t(p),
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boost::begin(r), boost::end(r)),
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make_filter_iterator(pred_t(p),
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boost::end(r), boost::end(r)))
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{ }
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};
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template< class T >
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struct filter_holder : holder<T>
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{
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filter_holder( T r ) : holder<T>(r)
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{ }
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};
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template< class SinglePassRange, class Predicate >
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inline filtered_range<Predicate, SinglePassRange>
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operator|(SinglePassRange& r,
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const filter_holder<Predicate>& f)
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{
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BOOST_RANGE_CONCEPT_ASSERT((SinglePassRangeConcept<SinglePassRange>));
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return filtered_range<Predicate, SinglePassRange>( f.val, r );
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}
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template< class SinglePassRange, class Predicate >
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inline filtered_range<Predicate, const SinglePassRange>
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operator|(const SinglePassRange& r,
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const filter_holder<Predicate>& f )
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{
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BOOST_RANGE_CONCEPT_ASSERT((
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SinglePassRangeConcept<const SinglePassRange>));
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return filtered_range<Predicate, const SinglePassRange>( f.val, r );
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}
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} // 'range_detail'
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// Unusual use of 'using' is intended to bring filter_range into the boost namespace
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// while leaving the mechanics of the '|' operator in range_detail and maintain
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// argument dependent lookup.
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// filter_range logically needs to be in the boost namespace to allow user of
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// the library to define the return type for filter()
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using range_detail::filtered_range;
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namespace adaptors
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{
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namespace
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{
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const range_detail::forwarder<range_detail::filter_holder>
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filtered =
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range_detail::forwarder<range_detail::filter_holder>();
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}
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template<class SinglePassRange, class Predicate>
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inline filtered_range<Predicate, SinglePassRange>
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filter(SinglePassRange& rng, Predicate filter_pred)
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{
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BOOST_RANGE_CONCEPT_ASSERT((
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SinglePassRangeConcept<SinglePassRange>));
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return range_detail::filtered_range<
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Predicate, SinglePassRange>( filter_pred, rng );
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}
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template<class SinglePassRange, class Predicate>
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inline filtered_range<Predicate, const SinglePassRange>
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filter(const SinglePassRange& rng, Predicate filter_pred)
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{
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BOOST_RANGE_CONCEPT_ASSERT((
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SinglePassRangeConcept<const SinglePassRange>));
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return range_detail::filtered_range<
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Predicate, const SinglePassRange>( filter_pred, rng );
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}
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} // 'adaptors'
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}
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#endif
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