// 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 filtered_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: | |
filtered_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 filtered_range<Predicate, InputRng> | |
operator|( InputRng& r, | |
const filter_holder<Predicate>& f ) | |
{ | |
return filtered_range<Predicate, InputRng>( f.val, r ); | |
} | |
template< class InputRng, class Predicate > | |
inline filtered_range<Predicate, const InputRng> | |
operator|( const InputRng& r, | |
const filter_holder<Predicate>& f ) | |
{ | |
return filtered_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::filtered_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 filtered_range<Predicate, InputRange> | |
filter(InputRange& rng, Predicate filter_pred) | |
{ | |
return range_detail::filtered_range<Predicate, InputRange>( filter_pred, rng ); | |
} | |
template<class InputRange, class Predicate> | |
inline filtered_range<Predicate, const InputRange> | |
filter(const InputRange& rng, Predicate filter_pred) | |
{ | |
return range_detail::filtered_range<Predicate, const InputRange>( filter_pred, rng ); | |
} | |
} // 'adaptors' | |
} | |
#endif |