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#ifndef MOZC_DATA_MANAGER_CONNECTION_FILE_READER_H_
#define MOZC_DATA_MANAGER_CONNECTION_FILE_READER_H_

#include <cstddef>
#include <cstdint>
#include <string>

#include "base/file_stream.h"

namespace mozc {

// Utility class to read connection_single_column.txt.
// Usage:
// for (ConnectionFileReader reader(filename); !reader.done(); reader.Next()) {
//   int rid = reader.rid_of_left_node();
//   ...
// }
class ConnectionFileReader {
 public:
  explicit ConnectionFileReader(const std::string& filename);
  ConnectionFileReader(const ConnectionFileReader&) = delete;
  ConnectionFileReader& operator=(const ConnectionFileReader&) = delete;
  ~ConnectionFileReader();

  bool done() const { return done_; }
  // Currently the matrix is square.
  size_t left_size() const { return pos_size_; }
  size_t right_size() const { return pos_size_; }
  int32_t rid_of_left_node() const { return array_index_ / pos_size_; }
  int32_t lid_of_right_node() const { return array_index_ % pos_size_; }
  int32_t cost() const { return cost_; }

  void Next();

 private:
  InputFileStream stream_;
  bool done_;
  size_t pos_size_;
  int32_t array_index_;
  int32_t cost_;
};

}  // namespace mozc

#endif  // MOZC_DATA_MANAGER_CONNECTION_FILE_READER_H_
