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#pragma once
#include "std/unique_ptr.hpp"
namespace coding
{
class CompressedBitVector;
}
namespace search
{
namespace v2
{
// A lightweight filter of features.
//
// NOTE: this class and its subclasses *ARE* thread-safe.
class FeaturesFilter
{
public:
FeaturesFilter(coding::CompressedBitVector const & filter, uint32_t threshold);
virtual ~FeaturesFilter() = default;
bool NeedToFilter(coding::CompressedBitVector const & features) const;
virtual unique_ptr<coding::CompressedBitVector> Filter(
coding::CompressedBitVector const & cbv) const = 0;
protected:
coding::CompressedBitVector const & m_filter;
uint32_t const m_threshold;
};
// Exact filter - leaves only features belonging to the set it was
// constructed from.
class LocalityFilter : public FeaturesFilter
{
public:
LocalityFilter(coding::CompressedBitVector const & filter);
// FeaturesFilter overrides:
unique_ptr<coding::CompressedBitVector> Filter(
coding::CompressedBitVector const & cbv) const override;
};
// Fuzzy filter - tries to leave only features belonging to the set it
// was constructed from, but if the result is empty, leaves at most
// first |threshold| features instead. This property is quite useful
// when there are no matching features in viewport but it's ok to
// process a limited number of features outside the viewport.
class ViewportFilter : public FeaturesFilter
{
public:
ViewportFilter(coding::CompressedBitVector const & filter, uint32_t threshold);
// FeaturesFilter overrides:
unique_ptr<coding::CompressedBitVector> Filter(
coding::CompressedBitVector const & cbv) const override;
};
} // namespace v2
} // namespace search
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