FileRead.cpp

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#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <sstream>
 
#include "moab/Core.hpp"
#include "moab/ReadUtilIface.hpp"
 
using namespace std;
using namespace moab;
 
int comment( string& line )
{
 // if a line starts with '#' is a comment
 // eat white space characters
 size_t found = line.find_first_not_of( " \t" );
 if( found == string::npos ) return 1; // empty line
 if( '#' == line[found] ) return 1; // a comment indeed
 return 0; // a line with some data in it, then
}
ErrorCode ReadTriangleOutput( Interface* mb, string fileBase )
{
 
 //
 // get the read interface from moab
 ReadUtilIface* iface;
 ErrorCode rval = mb->query_interface( iface );
 //
 if( MB_SUCCESS != rval )
 {
 cout << "Can't get interface.\n";
 return MB_FAILURE;
 }
 // Triangle default <name>.node
 string nodeFileName = fileBase + ".node";
 ifstream nodeFile( nodeFileName.c_str() );
 if( !nodeFile.is_open() )
 {
 cout << "can't open node file .\n";
 return MB_FILE_DOES_NOT_EXIST;
 }
 cout << "reading nodes from file " << nodeFileName.c_str() << endl;
 
 string eleFileName = fileBase + ".ele";
 ifstream eleFile( eleFileName.c_str() );
 if( !eleFile.is_open() )
 {
 cout << "can't open element file .\n";
 return MB_FILE_DOES_NOT_EXIST;
 }
 cout << "reading elements from file " << eleFileName.c_str() << endl;
 
 string line;
 
 // ignore comment lines that start with #
 
 int num_nodes = 0, num_triangles = 0;
 while( num_nodes == 0 )
 {
 getline( nodeFile, line );
 if( comment( line ) ) continue;
 stringstream tks( line );
 tks >> num_nodes; // ignore the rest of the first line
 // maybe will read attributes some other time
 cout << "num nodes:" << num_nodes << endl;
 }
 
 // allocate a block of vertex handles and read xyz’s into them
 // we know the size of the node arrays, and this call will allocate
 // needed arrays, coordinate arrays
 // also, it will return a starting handle for the node sequence
 vector< double* > arrays;
 EntityHandle startv;
 rval = iface->get_node_coords( 2, num_nodes, 0, startv, arrays );
 for( int i = 0; i < num_nodes; i++ )
 {
 getline( nodeFile, line );
 if( comment( line ) )
 {
 i--; // read one more line
 continue;
 }
 stringstream tokens( line );
 int nodeId;
 tokens >> nodeId >> arrays[0][i] >> arrays[1][i];
 }
 
 // now read the element data from a different file
 // first, find out how many elements are out there
 // first line with data should have it
 while( num_triangles == 0 )
 {
 getline( eleFile, line );
 if( comment( line ) ) continue;
 stringstream tks( line );
 tks >> num_triangles; // ignore the rest of the line
 cout << "num triangles:" << num_triangles << endl;
 }
 
 EntityHandle starte;
 EntityHandle* starth; // the connectivity array that will get populated
 // with triangle data
 // allocate block of triangle handles and read connectivity into them
 rval = iface->get_element_connect( num_triangles, 3, MBTRI, 0, starte, starth );
 
 for( int j = 0; j < num_triangles; j++ )
 {
 getline( eleFile, line );
 if( comment( line ) )
 {
 j--; // read one more line
 continue;
 }
 stringstream tokens( line );
 int eleId;
 unsigned int node;
 tokens >> eleId;
 for( int k = 0; k < 3; k++ )
 {
 tokens >> node;
 // vertex handles start at startv
 starth[3 * j + k] = startv + node - 1;
 }
 }
 
 mb->release_interface( iface );
 //
 return MB_SUCCESS;
}
 
// .
// Read Triangle output files
// Assume that the format is <filename>.node and <filename>.ele
// see http://www.cs.cmu.edu/~quake/triangle.html for details
//
int main( int argc, char** argv )
{
 if( 3 != argc )
 {
 cout << "Usage: " << argv[0] << " <filename> <outFile> " << endl;
 cout << " <filename> is the base file name; *.ele and *.node file are read; outFile "
 "is a file with an extension recognized by MOAB "
 << endl;
 return 0;
 }
 
 string filename = argv[1];
 char* outfile = argv[2];
 
 // get MOAB instance and read the file
 Core* mb = new Core();
 
 ErrorCode rval = ReadTriangleOutput( mb, filename );
 
 if( rval == MB_SUCCESS )
 {
 cout << "Writing output file " << outfile << endl;
 mb->write_file( outfile );
 }
 
 delete mb;
 
 return 0;
}