# usecases/c/UsesCase_MEDmesh_3.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/>.
     */

    /*
     *  Use case 3 : read an unstructured mesh : generic approach
     */

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

    #include <string.h>

    int main (int argc, char **argv) {
      med_idt fid;
      char meshname[MED_NAME_SIZE+1]="";
      char meshdescription[MED_COMMENT_SIZE+1]="";
      med_int meshdim=0;
      med_int spacedim=0;
      med_sorting_type sortingtype;
      med_int nstep;
      med_mesh_type meshtype;
      med_axis_type axistype;
      char *axisname="";
      char *unitname="";
      char dtunit[MED_SNAME_SIZE+1]="";
      med_float *coordinates = NULL;
      med_int nnodes = 0;
      med_int ngeo = 0;
      med_int nelt=0;
      med_int *connectivity = NULL;
      med_bool coordinatechangement;
      med_bool geotransformation;
      med_int i, j, it, nmesh;
      med_geometry_type geotype;
      med_geometry_type *geotypes = MED_GET_CELL_GEOMETRY_TYPE;
      char geotypename[MED_NAME_SIZE+1];
      int ret=-1;

      /* open MED file with READ ONLY access mode */
      fid = MEDfileOpen("UsesCase_MEDmesh_1.med",MED_ACC_RDONLY);
      if (fid < 0) {
        MESSAGE("ERROR : open file in READ ONLY ACCESS mode ...");
        goto ERROR;
      }

      /* read how many mesh in the file */
      if ((nmesh = MEDnMesh(fid)) < 0) {
        MESSAGE("ERROR : read how many mesh ...");
        goto ERROR;
      }

      for (i=0;i<nmesh;i++) {

        /* read computation space dimension */
        if ((spacedim = MEDmeshnAxis(fid, i+1)) < 0) {
          MESSAGE("ERROR : read computation space dimension ...");
          goto ERROR;
        }

        /* memory allocation */
        if ((axisname  = (char*) malloc(MED_SNAME_SIZE*spacedim+1)) == NULL) {
          MESSAGE("ERROR : memory allocation ...");
          goto ERROR;
        }
        if ((unitname  = (char*) malloc(MED_SNAME_SIZE*spacedim+1)) == NULL) {
          MESSAGE("ERROR : memory allocation ...");
          goto ERROR;
        }

        /* read mesh informations : meshname, mesh dimension, mesh type ... */
        if (MEDmeshInfo(fid, i+1, meshname, &spacedim, &meshdim, &meshtype, meshdescription,
                        dtunit, &sortingtype, &nstep, &axistype, axisname, unitname) < 0) {
          MESSAGE("ERROR : mesh info ...");
          free(axisname); free(unitname);
          goto ERROR;
        }

        free(axisname);
        free(unitname);

        /* read how many nodes in the mesh */
        if ((nnodes = MEDmeshnEntity(fid, meshname, MED_NO_DT, MED_NO_IT, MED_NODE, MED_NO_GEOTYPE,
                                     MED_COORDINATE, MED_NO_CMODE,&coordinatechangement,
                                     &geotransformation)) < 0) {
          MESSAGE("ERROR : number of nodes ...");
        goto ERROR;
        }

        /* read mesh nodes coordinates */
        if ((coordinates = (med_float*) malloc(sizeof(med_float)*nnodes*spacedim)) == NULL) {
          MESSAGE("ERROR : memory allocation ...");
          goto ERROR;
        }

        if (MEDmeshNodeCoordinateRd(fid, meshname, MED_NO_DT, MED_NO_IT, MED_FULL_INTERLACE,
                                    coordinates) < 0) {
          MESSAGE("ERROR : nodes coordinates ...");
          free(coordinates);
          goto ERROR;
        }

        if (coordinates)
          free(coordinates);

        /* read number of geometrical types for cells */
        if ((ngeo = MEDmeshnEntity(fid, meshname, MED_NO_DT, MED_NO_IT, MED_CELL,MED_GEO_ALL,
                                   MED_CONNECTIVITY, MED_NODAL,&coordinatechangement,
                                   &geotransformation)) < 0) {
          MESSAGE("ERROR : number of cell ...");
          ISCRUTE(geotype);
          goto ERROR;
        }

        for (it=1; it<=ngeo; it++) {

          /* get geometry type */
          if ((nelt = MEDmeshEntityInfo(fid, meshname, MED_NO_DT, MED_NO_IT,MED_CELL,it,
                                       geotypename,&geotype)) < 0) {
            MESSAGE("ERROR : number of cell ...");
            ISCRUTE(it);
            goto ERROR;
          }

          /* how many cells of type geotype ? */
          if ((nelt = MEDmeshnEntity(fid, meshname, MED_NO_DT, MED_NO_IT, MED_CELL,geotype,
                                     MED_CONNECTIVITY, MED_NODAL,&coordinatechangement,
                                       &geotransformation)) < 0) {
            MESSAGE("ERROR : number of cell ...");
            goto ERROR;
          }

          /* read cells connectivity in the mesh */
          if ((connectivity = (med_int *) malloc(sizeof(med_int)*nelt*(geotype%100))) == NULL) {
            MESSAGE("ERROR : memory allocation ...");
            goto ERROR;
          }

          if (MEDmeshElementConnectivityRd(fid, meshname, MED_NO_DT, MED_NO_IT, MED_CELL,
                                           geotype, MED_NODAL, MED_FULL_INTERLACE, connectivity) < 0) {
            MESSAGE("ERROR : cellconnectivity ...");
            ISCRUTE(geotype);
            free(connectivity);
            goto ERROR;
          }

          /* memory deallocation */
          if (connectivity) {
            free(connectivity);
            connectivity = NULL;
          }

        }

      }

      /*
       * ... we know that the family number of nodes and elements is 0, a real working would check ...
       */
      ret=0;
     ERROR:

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

      return ret;
    }