[3408] | 1 | // Boost.Range library |
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| 2 | // |
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| 3 | // Copyright Thorsten Ottosen, Neil Groves 2006 - 2008. Use, modification and |
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| 4 | // distribution is subject to the Boost Software License, Version |
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| 5 | // 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 6 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 7 | // |
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| 8 | // For more information, see http://www.boost.org/libs/range/ |
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| 9 | // |
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| 10 | |
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| 11 | #ifndef BOOST_RANGE_ADAPTOR_FILTERED_HPP |
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| 12 | #define BOOST_RANGE_ADAPTOR_FILTERED_HPP |
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| 13 | |
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| 14 | #include <boost/range/adaptor/argument_fwd.hpp> |
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| 15 | #include <boost/range/iterator_range.hpp> |
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| 16 | #include <boost/iterator/filter_iterator.hpp> |
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| 17 | |
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| 18 | namespace boost |
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| 19 | { |
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| 20 | namespace range_detail |
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| 21 | { |
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| 22 | template< class P, class R > |
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| 23 | struct filter_range : |
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| 24 | boost::iterator_range< |
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| 25 | boost::filter_iterator< P, |
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| 26 | BOOST_DEDUCED_TYPENAME range_iterator<R>::type |
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| 27 | > |
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| 28 | > |
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| 29 | { |
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| 30 | private: |
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| 31 | typedef boost::iterator_range< |
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| 32 | boost::filter_iterator< P, |
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| 33 | BOOST_DEDUCED_TYPENAME range_iterator<R>::type |
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| 34 | > |
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| 35 | > base; |
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| 36 | public: |
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| 37 | filter_range( P p, R& r ) |
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| 38 | : base( make_filter_iterator( p, boost::begin(r), boost::end(r) ), |
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| 39 | make_filter_iterator( p, boost::end(r), boost::end(r) ) ) |
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| 40 | { } |
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| 41 | }; |
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| 42 | |
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| 43 | template< class T > |
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| 44 | struct filter_holder : holder<T> |
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| 45 | { |
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| 46 | filter_holder( T r ) : holder<T>(r) |
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| 47 | { } |
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| 48 | }; |
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| 49 | |
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| 50 | template< class InputRng, class Predicate > |
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| 51 | inline filter_range<Predicate, InputRng> |
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| 52 | operator|( InputRng& r, |
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| 53 | const filter_holder<Predicate>& f ) |
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| 54 | { |
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| 55 | return filter_range<Predicate, InputRng>( f.val, r ); |
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| 56 | } |
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| 57 | |
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| 58 | template< class InputRng, class Predicate > |
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| 59 | inline filter_range<Predicate, const InputRng> |
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| 60 | operator|( const InputRng& r, |
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| 61 | const filter_holder<Predicate>& f ) |
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| 62 | { |
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| 63 | return filter_range<Predicate, const InputRng>( f.val, r ); |
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| 64 | } |
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| 65 | |
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| 66 | } // 'range_detail' |
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| 67 | |
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| 68 | // Unusual use of 'using' is intended to bring filter_range into the boost namespace |
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| 69 | // while leaving the mechanics of the '|' operator in range_detail and maintain |
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| 70 | // argument dependent lookup. |
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| 71 | // filter_range logically needs to be in the boost namespace to allow user of |
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| 72 | // the library to define the return type for filter() |
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| 73 | using range_detail::filter_range; |
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| 74 | |
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| 75 | namespace adaptors |
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| 76 | { |
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| 77 | namespace |
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| 78 | { |
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| 79 | const range_detail::forwarder<range_detail::filter_holder> |
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| 80 | filtered = |
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| 81 | range_detail::forwarder<range_detail::filter_holder>(); |
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| 82 | } |
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| 83 | |
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| 84 | template<class InputRange, class Predicate> |
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| 85 | inline filter_range<Predicate, InputRange> |
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| 86 | filter(InputRange& rng, Predicate filter_pred) |
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| 87 | { |
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| 88 | return range_detail::filter_range<Predicate, InputRange>( filter_pred, rng ); |
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| 89 | } |
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| 90 | |
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| 91 | template<class InputRange, class Predicate> |
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| 92 | inline filter_range<Predicate, const InputRange> |
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| 93 | filter(const InputRange& rng, Predicate filter_pred) |
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| 94 | { |
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| 95 | return range_detail::filter_range<Predicate, const InputRange>( filter_pred, rng ); |
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| 96 | } |
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| 97 | } // 'adaptors' |
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| 98 | |
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| 99 | } |
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| 100 | |
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| 101 | #endif |
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