IO_Flags.hh

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/* Copyright (C) 2014, 2015, 2018, 2019, 2020, 2023, 2024, 2025 PISM Authors
 *
 * This file is part of PISM.
 *
 * PISM is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 3 of the License, or (at your option) any later
 * version.
 *
 * PISM is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PISM; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#ifndef PISM_IO_FLAGS_H
#define PISM_IO_FLAGS_H
 
#include <string>
 
namespace pism {
 
/*!
 * Axis corresponding to dimensions (and coordinate variables) in a NetCDF file.
 *
 * Values of T_AXIS, X_AXIS, Y_AXIS, Z_AXIS are also used as indexes
 * in `start` and `count` arrays -- this is why they have consecutive values
 * starting from 0.
 */
enum AxisType : int { T_AXIS = 0, X_AXIS = 1, Y_AXIS = 2, Z_AXIS = 3, UNKNOWN_AXIS = 4, EXP_ID_AXIS = 5 };
 
AxisType axis_type_from_string(const std::string &input);
 
namespace io {
 
// I/O Flags used by File and NCFile. They are used in both interfaces,
// but I want to be able to create Python wrappers for File without
// exposing NCFile, and NCFile should compile without File, so it does
// not belong in either File.hh or NCFile.hh.
 
// This is a subset of NetCDF data-types.
enum Type : int {
  PISM_NAT    = 0,              /* NAT = 'Not A Type' (c.f. NaN) */
  PISM_BYTE   = 1,              /* signed 1 byte integer */
  PISM_CHAR   = 2,              /* ISO/ASCII character */
  PISM_SHORT  = 3,              /* signed 2 byte integer */
  PISM_INT    = 4,              /* signed 4 byte integer */
  PISM_FLOAT  = 5,              /* single precision floating point number */
  PISM_DOUBLE = 6               /* double precision floating point number */
};
 
enum Backend : int {
  PISM_GUESS,
  PISM_NETCDF3,
  PISM_NETCDF4_SERIAL,
  PISM_NETCDF4_PARALLEL,
  PISM_PNETCDF
};
 
// This is a subset of NetCDF file modes. Use values that don't match
// NetCDF flags so that we can detect errors caused by passing these
// straight to NetCDF.
enum Mode : int {
  //! open an existing file for reading only
  PISM_READONLY = 7,
  //! open an existing file for reading and writing
  PISM_READWRITE = 8,
  //! create a file for writing, overwrite if present
  PISM_READWRITE_CLOBBER = 9,
  //! create a file for writing, move foo.nc to foo.nc~ if present
  PISM_READWRITE_MOVE = 10
};
 
// This is the special value corresponding to the "unlimited" dimension length.
// Gets cast to "int", so it should match the value used by NetCDF.
enum Dim_Length : int { PISM_UNLIMITED = 0 };
 
// "Fill" mode. Gets cast to "int", so it should match values used by NetCDF.
enum Fill_Mode : int { PISM_FILL = 0, PISM_NOFILL = 0x100 };
 
/*!
 * Default value to use when a regridding variable is not found.
 */
class Default {
public:
 
  /*!
   * No default value: stop if the variable was not found.
   */
  static Default Nil() {
    return {};
  }
 
  /*!
   * Use this default value if the variable was not found.
   */
  Default(double v) {
    m_exists = true;
    m_value  = v;
  }
 
  /*!
   * True if the default value exists.
   */
  bool exists() const {
    return m_exists;
  }
 
  /*!
   * Convert the default value to `double`.
   */
  operator double() const {
    return m_value;
  }
 
private:
  Default() {
    m_exists = false;
    m_value  = 0;
  }
  double m_value;
  bool m_exists;
};
 
} // namespace io
 
} // end of namespace pism
 
#endif /* PISM_IO_FLAGS_H */