Example: C code

#include "cctk.h"
#include "cctk_Arguments.h"
#include "cctk_Parameters.h"

#include "SpaceMask.h"

/*
 * Register a mask type with three states.
 */
void Eg_RegisterMask (void)
{
  char *state_list_excision[3] = {"normal", "excise", "boundary"};

  SpaceMask_RegisterType("excision", 3, state_list_excision);

  return;
}

/*
 * Set the mask to the ``normal'' state at each point using the
 * slower name-reference function. See below for an example using
 * the faster bitwise operator to check the mask states.
 */
void Eg_SetMaskStates (CCTK_ARGUMENTS)
{
  DECLARE_CCTK_ARGUMENTS
  DECLARE_CCTK_PARAMETERS

  int i, j, k, ijk;

  for (k=0; k<cctk_lsh[2]; ++k)
  {
    for (j=0; j<cctk_lsh[1]; ++j)
    {
      for (i=0; i<cctk_lsh[0]; ++i)
      {
        ijk = CCTK_GFINDEX3D(cctkGH, i, j, k);
	
        SpaceMask_SetState(space_mask, ijk, "excision", "normal");
      }
    }
  }
  return;
}

/*
 * Check which of the points of the mask have been set to the
 * ``boundary'' state using the bitwise macro.
 */
void Eg_CheckMaskStates (CCTK_ARGUMENTS)
{
  DECLARE_CCTK_ARGUMENTS
  DECLARE_CCTK_PARAMETERS

  int i, j, k, ijk;

  CCTK_INT excision_mask;
  CCTK_INT boundary_mask;

  excision_mask = SpaceMask_GetTypeBits("excision");
  boundary_mask = SpaceMask_GetStateBits("boundary");

  for (k=0; k<cctk_lsh[2]; ++k)
  {
    for (j=0; j<cctk_lsh[1]; ++j)
    {
      for (i=0; i<cctk_lsh[0]; ++i)
      {
        ijk = CCTK_GFINDEX3D(cctkGH, i, j, k);

        if (SpaceMask_CheckStateBits(space_mask, ijk, excision_mask,
                                     boundary_mask))
        {
          CCTK_VINFO(CCTK_THORNSTRING, 
                     "Point (%d,%d,%d) is a boundary point.\n",
                     i, j, k);
        }
      }
    }
  }
  return;
}