#include <iostream>
#include "HepMC/GenEvent.h"
#include "HepMC/IO_GenEvent.h"

using namespace std;

int main(int argc, char** argv)
{
  if (argc < 2) {
    cerr << "needs file name!" << endl;
    return 1;
  }
  char* fname = argv[1];
  cout << "reading event from " << fname << endl;

  istream *infile = new fstream(fname, ios::in);

  HepMC::IO_GenEvent io(*infile);
  HepMC::GenEvent *evt = new HepMC::GenEvent();
  
  unsigned int cnt(0);
  while (cnt < 1000000) {
    if (io.rdstate() != 0) {
      cerr << "io.rdstate() != 0" << endl;
      return 1;
    }
    if (!io.fill_next_event(evt)) {
      cerr << "io.fill_next_event(evt) failed!" << endl;
      cerr << "  error: " << io.error_message() << "  (type: " 
           << io.error_type() << ")" << endl;
      return 2;
    } else {
      cout << "read event #" << cnt << endl;
      cnt++;
    }
  }
  cout << "read " << cnt << " events in total";
  return 0;
}