matlab/src/feather_writer.h

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#ifndef ARROW_MATLAB_FEATHER_WRITER_H
#define ARROW_MATLAB_FEATHER_WRITER_H

#include <memory>
#include <string>

#include <arrow/ipc/feather.h>
#include <arrow/status.h>
#include <arrow/type.h>

#include <matrix.h>

namespace arrow {
namespace matlab {

class FeatherWriter {
 public:
  ~FeatherWriter() = default;

  /// \brief Write Feather file metadata using information from an mxArray* struct.
  ///        The input mxArray must be a scalar struct array with the following fields:
  ///         - "Description" :: Nx1 mxChar array, table-level description
  ///         - "NumRows" :: scalar mxDouble array, number of rows in table
  ///         - "NumVariables" :: scalar mxDouble array, total number of variables
  /// \param[in] metadata mxArray* scalar struct containing table-level metadata
  void WriteMetadata(const mxArray* metadata);

  /// \brief Write mxArrays to a Feather file. The input must be a N-by-1 mxStruct
  //         array with the following fields:
  ///         - "Name" :: Nx1 mxChar array, name of the column
  ///         - "Type" :: Nx1 mxChar array, the variable's MATLAB datatype
  ///         - "Data" :: Nx1 mxArray, data for this variable
  ///         - "Valid" :: Nx1 mxLogical array, 0 represents invalid (null) values and
  ///                                           1 represents valid (non-null) values
  /// \param[in] variables mxArray* struct array containing table variable data
  /// \return status
  Status WriteVariables(const mxArray* variables);

  /// \brief Initialize a FeatherWriter object that writes to a Feather file
  /// \param[in] filename path to the new Feather file
  /// \param[out] feather_writer uninitialized FeatherWriter object
  /// \return status
  static Status Open(const std::string& filename,
                     std::shared_ptr<FeatherWriter>* feather_writer);

 private:
  FeatherWriter() = default;

  std::unique_ptr<ipc::feather::TableWriter> table_writer_;
  int64_t num_rows_;
  int64_t num_variables_;
  std::string description_;
};

}  // namespace matlab
}  // namespace arrow

#endif  // ARROW_MATLAB_FEATHER_WRITER_H