| // 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/iterator_range.hpp> |
| #include <boost/iterator/filter_iterator.hpp> |
| |
| namespace boost |
| { |
| namespace range_detail |
| { |
| template< class P, class R > |
| struct filter_range : |
| boost::iterator_range< |
| boost::filter_iterator< P, |
| BOOST_DEDUCED_TYPENAME range_iterator<R>::type |
| > |
| > |
| { |
| private: |
| typedef boost::iterator_range< |
| boost::filter_iterator< P, |
| BOOST_DEDUCED_TYPENAME range_iterator<R>::type |
| > |
| > base; |
| public: |
| filter_range( P p, R& r ) |
| : base( make_filter_iterator( p, boost::begin(r), boost::end(r) ), |
| make_filter_iterator( p, boost::end(r), boost::end(r) ) ) |
| { } |
| }; |
| |
| template< class T > |
| struct filter_holder : holder<T> |
| { |
| filter_holder( T r ) : holder<T>(r) |
| { } |
| }; |
| |
| template< class InputRng, class Predicate > |
| inline filter_range<Predicate, InputRng> |
| operator|( InputRng& r, |
| const filter_holder<Predicate>& f ) |
| { |
| return filter_range<Predicate, InputRng>( f.val, r ); |
| } |
| |
| template< class InputRng, class Predicate > |
| inline filter_range<Predicate, const InputRng> |
| operator|( const InputRng& r, |
| const filter_holder<Predicate>& f ) |
| { |
| return filter_range<Predicate, const InputRng>( 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::filter_range; |
| |
| namespace adaptors |
| { |
| namespace |
| { |
| const range_detail::forwarder<range_detail::filter_holder> |
| filtered = |
| range_detail::forwarder<range_detail::filter_holder>(); |
| } |
| |
| template<class InputRange, class Predicate> |
| inline filter_range<Predicate, InputRange> |
| filter(InputRange& rng, Predicate filter_pred) |
| { |
| return range_detail::filter_range<Predicate, InputRange>( filter_pred, rng ); |
| } |
| |
| template<class InputRange, class Predicate> |
| inline filter_range<Predicate, const InputRange> |
| filter(const InputRange& rng, Predicate filter_pred) |
| { |
| return range_detail::filter_range<Predicate, const InputRange>( filter_pred, rng ); |
| } |
| } // 'adaptors' |
| |
| } |
| |
| #endif |