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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include "zc4_posting_writer_base.h"
namespace search::index { class DocIdAndFeatures; }
namespace search::diskindex {
/*
* Class used to write posting lists of type "Zc.4" and "Zc.5" (dynamic k).
*
* Common words have docid deltas and skip info separate from
* features. If "cheap" features are enabled then they are interleaved
* with docid deltas for quick access during sequential scan while the
* full features still remains separate.
*
* Rare words do not have skip info, and docid deltas and features are
* interleaved.
*/
template <bool bigEndian>
class Zc4PostingWriter : public Zc4PostingWriterBase
{
using EncodeContext = bitcompression::FeatureEncodeContext<bigEndian>;
EncodeContext _encode_context;
// Buffer up features in memory
EncodeContext *_encode_features;
public:
Zc4PostingWriter(const Zc4PostingWriter &) = delete;
Zc4PostingWriter(Zc4PostingWriter &&) = delete;
Zc4PostingWriter &operator=(const Zc4PostingWriter &) = delete;
Zc4PostingWriter &operator=(Zc4PostingWriter &&) = delete;
Zc4PostingWriter(index::PostingListCounts &counts);
~Zc4PostingWriter();
void reset_chunk();
void flush_word_with_skip(bool hasMore);
void flush_word_no_skip();
void flush_word();
void write_docid_and_features(const index::DocIdAndFeatures &features);
void set_encode_features(EncodeContext *encode_features);
void on_open();
void on_close();
EncodeContext &get_encode_features() { return *_encode_features; }
EncodeContext &get_encode_context() { return _encode_context; }
};
extern template class Zc4PostingWriter<false>;
extern template class Zc4PostingWriter<true>;
}
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