OdbApiIO.h

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/*
 * (C) Copyright 2018 UCAR
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 */

#ifndef FILEIO_ODBAPIIO_H_
#define FILEIO_ODBAPIIO_H_

#include <string>

#include "odb_api/odbql.h"

#include "oops/util/ObjectCounter.h"

#include "fileio/IodaIO.h"

////////////////////////////////////////////////////////////////////////
// Implementation of IodaIO for ODB API.
////////////////////////////////////////////////////////////////////////

// Forward declarations
namespace eckit {
  class Configuration;
}

namespace ioda {

/*! \brief Implementation of IodaIO for ODB API.
 *
 * \details The OdbOpiIO class defines the constructor and methods for
 *          the abstract class IodaIO.
 *
 * \author Steven Vahl (NCAR)
 */
class OdbApiIO : public IodaIO,
                 private util::ObjectCounter<OdbApiIO> {
 public:
  /*!
   * \brief classname method for object counter
   *
   * \details This method is supplied for the ObjectCounter base class.
   *          It defines a name to identify an object of this class
   *          for reporting by OOPS.
   */
  static const std::string classname() {return "ioda::OdbApiIO";}

  OdbApiIO(const std::string & FileName, const std::string & FileMode,
           const std::size_t & Nlocs, const std::size_t & Nobs,
           const std::size_t & Nrecs, const std::size_t & Nvars);
  ~OdbApiIO();

  void ReadVar(const std::string & VarName, int* VarData);
  void ReadVar(const std::string & VarName, float* VarData);
  void ReadVar(const std::string & VarName, double* VarData);

  void WriteVar(const std::string & VarName, int* VarData);
  void WriteVar(const std::string & VarName, float* VarData);
  void WriteVar(const std::string & VarName, double* VarData);

  void ReadDateTime(int* VarDate, int* VarTime);

 private:
  // For the oops::Printable base class
  void print(std::ostream & os) const;

  // int CreateReadVarSQL(const std::string & VarName, int expectedType, odbql_stmt **res);
  // int RetrieveColValPtr(odbql_stmt* res, int col, odbql_value **ppv);
  template <class T>
  void ReadVarTemplate(const std::string & VarName, T* VarData);


  // Data members
  /*!
   * \brief pointer to odbql object
   *
   * \details This data member is a pointer to a odbql type. The
   *          odbql type is returned by the odbql_open function and
   *          is used by all following odb api functions to interact with 
   *          the odb api file.
   */
  odbql *db_ = nullptr;
  // TODO(sv) Maybe better to use unique_ptr, but causes compiler error of
  // "incomplete type 'odbql'"
  // std::unique_ptr<odbql> db_;

  /*!
   * \brief pointer to odbql_stmt object used for selecting a single variable
   *
   * \details Rather than create a new odbql_stmt for every call to one of the
   *          ReadVar methods, we create a parameterized statement once for
   *          the OdbApiIO object. It is finalized in the class destructor.
   *
   *          On second thought, not sure about thread-safety of this approach. TABLE FOR NOW
   */
  // odbql_stmt *readvar_sql_ = nullptr;
};

}  // namespace ioda

#endif  // FILEIO_ODBAPIIO_H_