csv.hpp

#ifndef gencoefficents_shared_hpp
#define gencoefficents_shared_hpp

#include <vector>
#include <iostream>

#include <Eigen/Dense>

extern "C" {
#include <stdio.h>
#include "csv.h"
}

double stod_strict(const std::string& str);
float stof_strict(const std::string& str);
int stoi_strict(const std::string& str);

template<typename T, int _Rows=Eigen::Dynamic, int _Cols=Eigen::Dynamic>
Eigen::Matrix<T, _Rows, _Cols>
loadNamedRectCsv(const char *path,
                 std::vector<std::string> &colnames,
                 std::vector<std::string> &rownames,
                 T (*conv)(const std::string&)) {
  FILE *fd = fopen (path, "r");

  if (!fd)
    throw "unable to open file";

  csvfile csv;
  csv_parse(&csv, fd);

  colnames.clear();
  rownames.clear();

  size_t nfields = 0;
  const char **row = csv_readrow (&csv, &nfields);
  if (!row || nfields < 1) {
    std::cerr
      << "Unable to read header from CSV file '"
      << path << "'\n";
    exit(1);
  }

  colnames.reserve(nfields-1);
  colnames.reserve(16);
  std::vector<T> out;
  out.reserve(nfields * rownames.capacity());

  for (size_t i = 1; i < nfields; i++)
    colnames.push_back(row[i]);

  while ((row = csv_readrow (&csv, &nfields))) {
    if (nfields != colnames.size()+1) {
      std::cerr
	<< "Error: Number of data items doesn't match header, file '"
	<< path << "', line: "
	<< out.size()+2 << "\n";
      exit(1);
    }
    rownames.push_back(row[0]);
    for (size_t i = 1; i < nfields; i++) {
      out.push_back(conv(row[i]));
    }
  }

  csv_close (&csv);

  typedef Eigen::Matrix<T, _Rows, _Cols, Eigen::RowMajor> MatrixXR;
  return Eigen::Map<MatrixXR>(out.data(), rownames.size(), colnames.size());
}

template<typename T, int _Rows=Eigen::Dynamic, int _Cols=Eigen::Dynamic>
Eigen::Matrix<T, _Rows, _Cols>
loadRectCsv(const char *path, T (*conv)(const std::string&))
{
  std::vector<std::string> colnames, rownames;
  return loadNamedRectCsv(path, colnames, rownames, conv);
}

#endif