mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-10-22 00:10:52 +00:00
35 lines
1.3 KiB
C++
35 lines
1.3 KiB
C++
|
#pragma once
|
||
|
|
#include <type_traits>
|
||
|
|
#include <boost/range/adaptor/filtered.hpp>
|
||
|
|
|
||
|
|
|
||
|
|
/// Similar to boost::filtered_range but a little bit easier and allows to convert ordinary iterators to filtered
|
||
|
|
template <typename F, typename C>
|
||
|
|
struct RangeFiltered : public boost::iterator_range<boost::filter_iterator<F, decltype(std::end(C()))>>
|
||
|
|
{
|
||
|
|
using RawIterator = decltype(std::end(C()));
|
||
|
|
using FilterIterator = boost::filter_iterator<F, RawIterator>;
|
||
|
|
using Base = boost::iterator_range<FilterIterator>;
|
||
|
|
|
||
|
|
RangeFiltered(const F & filter, const C & container)
|
||
|
|
: Base(
|
||
|
|
FilterIterator(filter, std::begin(container), std::end(container)),
|
||
|
|
FilterIterator(filter, std::end(container), std::end(container))),
|
||
|
|
filter(filter) {}
|
||
|
|
|
||
|
|
/// Convert ordinary iterator to filtered one
|
||
|
|
/// Real position will be in range [ordinary_iterator; end()], so it is suitable to use with lower[upper]_bound()
|
||
|
|
inline FilterIterator convert(RawIterator ordinary_iterator) const
|
||
|
|
{
|
||
|
|
return {filter, ordinary_iterator, std::end(*this).end()};
|
||
|
|
}
|
||
|
|
|
||
|
|
F filter;
|
||
|
|
};
|
||
|
|
|
||
|
|
template <typename F, typename C>
|
||
|
|
inline decltype(auto) createRangeFiltered(F && filter, C && container)
|
||
|
|
{
|
||
|
|
return RangeFiltered<std::decay_t<F>, std::decay_t<C>>{std::forward<F>(filter), std::forward<C>(container)};
|
||
|
|
};
|