MOAB: Mesh Oriented datABase  (version 5.3.0)
ReadTemplate.cpp
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00001 /**
00002  * \class ReadTemplate
00003  * \brief Template for writing a new reader in MOAB
00004  *
00005  */
00006 
00007 #include "ReadTemplate.hpp"
00008 #include "moab/Interface.hpp"
00009 #include "moab/ReadUtilIface.hpp"
00010 #include "moab/Range.hpp"
00011 #include "moab/FileOptions.hpp"
00012 
00013 #include <cstdio>
00014 #include <cassert>
00015 
00016 namespace moab
00017 {
00018 
00019 ReaderIface* ReadTemplate::factory( Interface* iface )
00020 {
00021     return new ReadTemplate( iface );
00022 }
00023 
00024 ReadTemplate::ReadTemplate( Interface* impl ) : mbImpl( impl ), fileName( NULL )
00025 {
00026     mbImpl->query_interface( readMeshIface );
00027 }
00028 
00029 ReadTemplate::~ReadTemplate()
00030 {
00031     if( readMeshIface )
00032     {
00033         mbImpl->release_interface( readMeshIface );
00034         readMeshIface = 0;
00035     }
00036 }
00037 
00038 ErrorCode ReadTemplate::read_tag_values( const char* /* file_name */, const char* /* tag_name */,
00039                                          const FileOptions& /* opts */, std::vector< int >& /* tag_values_out */,
00040                                          const SubsetList* /* subset_list */ )
00041 {
00042     return MB_NOT_IMPLEMENTED;
00043 }
00044 
00045 ErrorCode ReadTemplate::load_file( const char* filename, const EntityHandle* file_set, const FileOptions& opts,
00046                                    const ReaderIface::SubsetList* subset_list, const Tag* /*file_id_tag*/ )
00047 {
00048     if( subset_list )
00049     {
00050         // See src/moab/ReaderIface.hpp, definition of SubsetList struct; this basically specifies
00051         // an integer tag and tag values for sets to read on this proc, or a part number and total #
00052         // parts for reading a trivial partition of entities
00053     }
00054 
00055     // Save filename to member variable so we don't need to pass as an argument
00056     // to called functions
00057     fileName = filename;
00058 
00059     // Process options; see src/FileOptions.hpp for API for FileOptions class, and
00060     // doc/metadata_info.doc for a description of various options used by some of the readers in
00061     // MOAB
00062     ErrorCode result = process_options( opts );MB_CHK_SET_ERR( result, fileName << ": problem reading options" );
00063 
00064     // Open file; filePtr is member of ReadTemplate, change to whatever mechanism is used to
00065     // identify file
00066     FILE* filePtr = fopen( fileName, "r" );
00067     if( !filePtr ) { MB_SET_ERR( MB_FILE_DOES_NOT_EXIST, fileName << ": fopen returned error" ); }
00068 
00069     // Read number of verts, elements, sets
00070     long num_verts = 0, num_elems = 0, num_sets = 0;
00071 
00072     // read_ents keeps a running set of entities read from this file, including vertices, elements,
00073     // and sets; these will get added to file_set (if input) at the end of the read
00074     Range read_ents;
00075 
00076     // start_vertex is passed back so we know how to convert indices from the file into vertex
00077     // handles; most of the time this is done by adding start_vertex to the (0-based) index; if the
00078     // index is 1-based, you also need to subtract one; see read_elements for details
00079     EntityHandle start_vertex;
00080     result = read_vertices( num_verts, start_vertex, read_ents );
00081     if( MB_SUCCESS != result )
00082     {
00083         fclose( filePtr );
00084         return result;
00085     }
00086 
00087     // Create/read elements; this template assumes that all elements are the same type, so can be
00088     // read in a single call to read_elements, and kept track of with a single start_elem handle. If
00089     // there are more entity types, might have to keep these start handles in an array/vector.
00090     // start_elem is only really needed if you're reading sets later, and need to convert some
00091     // file-based index to an entity handle
00092     EntityHandle start_elem;
00093     result = read_elements( num_elems, start_vertex, start_elem, read_ents );
00094     if( MB_SUCCESS != result )
00095     {
00096         fclose( filePtr );
00097         return result;
00098     }
00099 
00100     // Read/create entity sets; typically these sets have some tag identifying what they're for, see
00101     // doc/metadata_info.doc for examples of different kinds of sets and how they're marked
00102     result = create_sets( num_sets, start_vertex, num_verts, start_elem, num_elems, read_ents );
00103     if( MB_SUCCESS != result )
00104     {
00105         fclose( filePtr );
00106         return result;
00107     }
00108 
00109     // Finally, add all read_ents into the file set, if one was input
00110     if( file_set && *file_set )
00111     {
00112         result = mbImpl->add_entities( *file_set, read_ents );
00113         if( MB_SUCCESS != result )
00114         {
00115             fclose( filePtr );
00116             return result;
00117         }
00118     }
00119 
00120     fclose( filePtr );
00121 
00122     return result;
00123 }
00124 
00125 ErrorCode ReadTemplate::read_vertices( int num_verts, EntityHandle& start_vertex, Range& read_ents )
00126 {
00127     // Allocate nodes; these are allocated in one shot, get contiguous handles starting with
00128     // start_handle, and the reader is passed back double*'s pointing to MOAB's native storage for
00129     // vertex coordinates for those verts
00130     std::vector< double* > coord_arrays;
00131     ErrorCode result = readMeshIface->get_node_coords( 3, num_verts, 1, start_vertex, coord_arrays );MB_CHK_SET_ERR( result, fileName << ": Trouble reading vertices" );
00132 
00133     // Fill in vertex coordinate arrays
00134     double *x = coord_arrays[0], *y = coord_arrays[1], *z = coord_arrays[2];
00135     for( long i = 0; i < num_verts; ++i )
00136     {
00137         // Read x/y/z; do something with them for now to avoid warning
00138         if( x || y || z ) {}
00139     }
00140 
00141     if( num_verts ) read_ents.insert( start_vertex, start_vertex + num_verts - 1 );
00142 
00143     return result;
00144 }
00145 
00146 //! Read/create elements
00147 ErrorCode ReadTemplate::read_elements( int num_elems, EntityHandle start_vertex, EntityHandle& start_elem,
00148                                        Range& read_ents )
00149 {
00150     // Get the entity type being read
00151     EntityType ent_type = MBHEX;
00152 
00153     // Get the number of vertices per entity
00154     int verts_per_elem = 8;
00155 
00156     // Create the element sequence; passes back a pointer to the internal storage for connectivity
00157     // and the starting entity handle
00158     EntityHandle* conn_array;
00159     ErrorCode result =
00160         readMeshIface->get_element_connect( num_elems, verts_per_elem, ent_type, 1, start_elem, conn_array );MB_CHK_SET_ERR( result, fileName << ": Trouble reading elements" );
00161 
00162     // Read connectivity into conn_array directly
00163     for( long i = 0; i < num_elems; i++ )
00164     {
00165         // Read connectivity
00166     }
00167 
00168     // Convert file-based connectivity indices to vertex handles in-place; be careful, if indices
00169     // are smaller than handles, need to do from the end of the list so we don't overwrite data
00170     //
00171     // Here, we assume indices are smaller than handles, just for demonstration; create an
00172     // integer-type pointer to connectivity initialized to same start of connectivity array
00173     int* ind_array = reinterpret_cast< int* >( conn_array );
00174     // OFFSET is value of first vertex index in file; most files are 1-based, but some might be
00175     // 0-based
00176     int OFFSET = 1;
00177     for( long i = num_elems * verts_per_elem - 1; i >= 0; i-- )
00178     {
00179         conn_array[i] = ind_array[i] + start_vertex + OFFSET;
00180 
00181         // This assert assumes last handle in read_ents is highest vertex handle in this file
00182         assert( conn_array[i] >= start_vertex && conn_array[i] <= *read_ents.rbegin() );
00183     }
00184 
00185     // Notify MOAB of the new elements
00186     result = readMeshIface->update_adjacencies( start_elem, num_elems, verts_per_elem, conn_array );
00187     if( MB_SUCCESS != result ) return result;
00188 
00189     // Add elements to read_ents
00190     if( num_elems ) read_ents.insert( start_elem, start_elem + num_elems - 1 );
00191 
00192     return MB_SUCCESS;
00193 }
00194 
00195 //! Read/create sets
00196 ErrorCode ReadTemplate::create_sets( int num_sets, EntityHandle /*start_vertex*/, int /*num_verts*/,
00197                                      EntityHandle /*start_elem*/, int /*num_elems*/, Range& read_ents )
00198 {
00199     ErrorCode result = MB_SUCCESS;
00200     EntityHandle this_set;
00201 
00202     for( int i = 0; i < num_sets; i++ )
00203     {
00204         // Create set
00205         result = mbImpl->create_meshset( MESHSET_SET, this_set );MB_CHK_SET_ERR( result, fileName << ": Trouble creating set" );
00206 
00207         Range set_ents;
00208         // Read/compute what's in this set; REMEMBER TO CONVERT THESE TO MOAB HANDLES
00209 
00210         // Add them to the set
00211         result = mbImpl->add_entities( this_set, set_ents );MB_CHK_SET_ERR( result, fileName << ": Trouble putting entities in set" );
00212 
00213         // Add the new set to read_ents
00214         read_ents.insert( this_set );
00215     }
00216 
00217     return MB_SUCCESS;
00218 }
00219 
00220 ErrorCode ReadTemplate::process_options( const FileOptions& opts )
00221 {
00222     // Mark all options seen, to avoid compile warning on unused variable
00223     opts.mark_all_seen();
00224     return MB_SUCCESS;
00225 }
00226 
00227 }  // namespace moab
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