# usecases/c/UsesCase_MEDmesh_5.c

    /*  This file is part of MED.
     *
     *  COPYRIGHT (C) 1999 - 2012  EDF R&D, CEA/DEN
     *  MED is free software: you can redistribute it and/or modify
     *  it under the terms of the GNU Lesser General Public License as published by
     *  the Free Software Foundation, either version 3 of the License, or
     *  (at your option) any later version.
     *
     *  MED 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 Lesser General Public License for more details.
     *
     *  You should have received a copy of the GNU Lesser General Public License
     *  along with MED.  If not, see <http://www.gnu.org/licenses/>.
     */

    /*
     * Mesh Use case 5 : read a 2D structured mesh
     *                   5x3 cartesian grid
     *
     */

    #include <med.h>
    #define MESGERR 1
    #include <med_utils.h>

    #include <string.h>

    int main (int argc, char **argv) {
      med_idt fid;
      const char meshname[MED_NAME_SIZE+1]="2D structured mesh";
      med_int spacedim;
      med_int meshdim;
      char meshdescription[MED_COMMENT_SIZE+1];
      char axisname[2*MED_SNAME_SIZE+1];
      char unitname[2*MED_SNAME_SIZE+1];
      char dtunit[MED_SNAME_SIZE+1];
      med_mesh_type meshtype;
      med_axis_type axistype;
      med_grid_type gridtype;
      med_int axis, size ;
      med_float *cooXaxis = NULL;
      med_float *cooYaxis = NULL;
      med_bool coordinatechangement;
      med_bool geotransformation;
      med_int nstep;
      med_sorting_type sortingtype;
      int j;
      int ret=-1;
      int ncell=0;
      char *cellsname=NULL;

      /* open MED file */
      fid = MEDfileOpen("UsesCase_MEDmesh_4.med",MED_ACC_RDONLY);
      if (fid < 0) {
        MESSAGE("ERROR : open file ...");
        goto ERROR;
      }

      /* read mesh informations : meshname, mesh dimension, space dimension ... */
      if (MEDmeshInfoByName(fid, meshname, &spacedim, &meshdim, &meshtype, meshdescription,
                            dtunit, &sortingtype, &nstep, &axistype, axisname, unitname) < 0) {
        MESSAGE("ERROR : mesh info ...");
        goto ERROR;
      }

      /* read the grid type : MED_CARTESIAN_GRID or MED_CURVILINEAR_GRID */
      if (MEDmeshGridTypeRd(fid, meshname, &gridtype) < 0) {
        MESSAGE("ERROR : read grid type ...");
      }

      /*
       * ... we know that we the mesh is a cartesian grid,
       * a real code working would check  ...
       */

      /* read the axis coordinates (MED_CARTESIAN coordinates system */
      /* X */
      axis = 1;
      if ((size = MEDmeshnEntity(fid, meshname, MED_NO_DT, MED_NO_IT,
                                 MED_NODE, MED_NONE, MED_COORDINATE_AXIS1, MED_NO_CMODE,
                                 &coordinatechangement, &geotransformation)) < 0) {
        MESSAGE("ERROR : number of coordinates on X axis ...");
        goto ERROR;
      }
      ncell = size-1;

      if ((cooXaxis = (med_float *) malloc(sizeof(med_float)*size)) == NULL) {
        MESSAGE("ERROR : memory allocation ...");
        goto ERROR;
      }
      if (MEDmeshGridIndexCoordinateRd(fid, meshname, MED_NO_DT, MED_NO_IT,
                                       axis, cooXaxis) < 0) {
        MESSAGE("ERROR : read axis X coordinates ...");
        free(cooXaxis);
        goto ERROR;
      }

      free(cooXaxis);

      /* Y */
      axis = 2;
      if ((size = MEDmeshnEntity(fid, meshname, MED_NO_DT, MED_NO_IT,
                                 MED_NODE, MED_NONE, MED_COORDINATE_AXIS2, MED_NO_CMODE,
                                 &coordinatechangement, &geotransformation)) < 0) {
        MESSAGE("ERROR : number of coordinates on Y axis ...");
        goto ERROR;
      }
      ncell = ncell * (size-1);

      if ((cooYaxis = (med_float *) malloc(sizeof(med_float)*size)) == NULL) {
        MESSAGE("ERROR : memory allocation ...");
        goto ERROR;
      }
      if (MEDmeshGridIndexCoordinateRd(fid, meshname, MED_NO_DT, MED_NO_IT,
                                       axis, cooYaxis) < 0) {
        MESSAGE("ERROR : read axis Y coordinates ...");
        free(cooYaxis);
        goto ERROR;
      }

      free(cooYaxis);

      cellsname = (char *) malloc((sizeof(char))*ncell*MED_SNAME_SIZE+1);
      if (MEDmeshEntityNameRd(fid, meshname, MED_NO_DT, MED_NO_IT,
                              MED_CELL, MED_QUAD4, cellsname) < 0)  {
        MESSAGE("ERROR : read cells name ...");
        free(cellsname);
        goto ERROR;
      }
      free(cellsname);

      ret=0;
     ERROR:

      /* close MED file */
      if (MEDfileClose(fid) < 0) {
        MESSAGE("ERROR : close file ...");
        ret = -1;
      }

      return ret;
    }