file-io.hpp

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#ifndef _parameteric_curves_utils_file_io_hpp
#define _parameteric_curves_utils_file_io_hpp
 
#include <Eigen/Dense>
#include <fstream>  
 
#define MAXBUFSIZE ((int)1000000)
 
namespace parametriccurves {
namespace utils {
 
const Eigen::MatrixXd readMatrixFromFile(const std::string& filename) {
  int cols = 0, rows = 0;
  double buff[MAXBUFSIZE];
 
  // Read numbers from file into buffer.
  std::ifstream infile;
  infile.open(filename.c_str());
  while (!infile.eof()) {
    std::string line;
    getline(infile, line);
    //          std::cout<<"Read line "<<rows<<"\n";
 
    int temp_cols = 0;
    std::stringstream stream(line);
    while (!stream.eof()) stream >> buff[cols * rows + temp_cols++];
 
    if (temp_cols == 0) continue;
 
    if (cols == 0)
      cols = temp_cols;
    else if (temp_cols != cols && !infile.eof()) {
      std::cout << "Error while reading matrix from file, line " << rows
                << " has " << temp_cols
                << " columnds, while preceding lines had " << cols
                << " columnds\n";
      std::cout << line << "\n";
      break;
    }
 
    rows++;
    if ((rows + 1) * cols >= MAXBUFSIZE) {
      std::cout << "Max buffer size exceeded (" << rows << " rows, " << cols
                << " cols)\n";
      break;
    }
  }
  infile.close();
  rows--;
 
  // Populate matrix with numbers.
  Eigen::MatrixXd result(rows, cols);
  for (int i = 0; i < rows; i++)
    for (int j = 0; j < cols; j++) result(i, j) = buff[cols * i + j];
  return result;
}
 
}  // namespace utils
}  // namespace parametriccurves
 
#endif  //_CLASS_EXACTCUBIC