reader.hpp

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#pragma once
 
#include <fcb/error.hpp>
#include <fcb/feature.hpp>
#include <fcb/header.hpp>
#include <fcb/packed_rtree.hpp>
#include <fcb/range_reader.hpp>
#include <fcb/stree.hpp>
 
#include <cstdint>
#include <memory>
#include <string>
#include <vector>
 
namespace fcb {
 
struct SearchResultItem {
    std::uint64_t offset;  // relative to the features section
    std::uint64_t index;   // feature ordinal
};
 
enum class IterationMode {
    SequentialScan,  
    OffsetList,      
};
 
class FeatureIterator {
  public:
    FeatureIterator(std::shared_ptr<RangeReader> reader, HeaderView header, IterationMode mode,
                    std::vector<SearchResultItem> hits);
 
    FeatureIterator(const FeatureIterator&) = delete;
    FeatureIterator& operator=(const FeatureIterator&) = delete;
    FeatureIterator(FeatureIterator&&) = default;
    FeatureIterator& operator=(FeatureIterator&&) = delete;
 
    bool next();
 
    const Feature& current() const { return current_; }
 
    std::uint64_t features_count() const { return header_.info().features_count; }
 
  private:
    std::shared_ptr<RangeReader> reader_;
    HeaderView header_;
    IterationMode mode_;
    std::vector<SearchResultItem> hits_;
 
    Feature current_;
    std::uint64_t cursor_ = 0;   // absolute, for SequentialScan
    std::size_t hit_index_ = 0;  // for OffsetList
    std::uint64_t produced_ = 0;
};
 
class FcbReader {
  public:
    static FcbReader open_file(const std::string& path);
    static FcbReader open(std::shared_ptr<RangeReader> reader);
 
    const HeaderView& header() const { return header_; }
 
    FeatureIterator select_all();
 
    FeatureIterator select_bbox(const BBox& query);
 
    FeatureIterator select_attr(const AttrQuery& query, AttrQueryOptions opts = {});
 
  private:
    FcbReader(std::shared_ptr<RangeReader> reader, HeaderView header);
 
    std::shared_ptr<RangeReader> reader_;
    HeaderView header_;
};
 
}  // namespace fcb