Geant4EventReaderHepMC.cpp

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//==========================================================================
//  AIDA Detector description implementation 
//--------------------------------------------------------------------------
// Copyright (C) Organisation europeenne pour la Recherche nucleaire (CERN)
// All rights reserved.
//
// For the licensing terms see $DD4hepINSTALL/LICENSE.
// For the list of contributors see $DD4hepINSTALL/doc/CREDITS.
//
// Author     : M.Frank
//
//==========================================================================
 
// Framework include files
#include <DDG4/IoStreams.h>
#include <DDG4/Geant4InputAction.h>
 
// C/C++ include files
 
namespace dd4hep {
 
  namespace sim {
 
    namespace HepMC {
      class EventStream;
    }
 
 
    class Geant4EventReaderHepMC : public Geant4EventReader  {
      typedef boost::iostreams::stream<dd4hep_file_source<int> > in_stream;
      //typedef boost::iostreams::stream<dd4hep_file_source<TFile*> > in_stream;
      typedef HepMC::EventStream EventStream;
    protected:
      in_stream    m_input;
      EventStream* m_events;
    public:
      explicit Geant4EventReaderHepMC(const std::string& nam);
      virtual ~Geant4EventReaderHepMC();
      virtual EventReaderStatus readParticles(int event_number,
                                              Vertices& vertices,
                                              std::vector<Particle*>& particles)  override;
      virtual EventReaderStatus moveToEvent(int event_number)  override;
      virtual EventReaderStatus skipEvent() override { return EVENT_READER_OK; }
 
    };
  }     /* End namespace sim   */
}       /* End namespace dd4hep       */
 
//====================================================================
//  AIDA Detector description implementation 
//--------------------------------------------------------------------
//
//====================================================================
// #include <DDG4/Geant4EventReaderHepMC"
 
// Framework include files
#include <DDG4/Factories.h>
#include <DD4hep/Printout.h>
#include <DDG4/Geant4Primary.h>
#include <CLHEP/Units/SystemOfUnits.h>
#include <CLHEP/Units/PhysicalConstants.h>
 
// C/C++ include files
#include <cerrno>
#include <climits>
#include <algorithm>
 
using namespace dd4hep::sim;
using PropertyMask = dd4hep::detail::ReferenceBitMask<int>;
 
// Factory entry
DECLARE_GEANT4_EVENT_READER(Geant4EventReaderHepMC)
 
namespace dd4hep {
 
  namespace sim {
 
    namespace HepMC {
 
      /*
       *  \author  P.Kostka (main author)
       *  \author  M.Frank  (code reshuffeling into new DDG4 scheme)
       *  \version 1.0
       *  \ingroup DD4HEP_SIMULATION
       */
      class EventHeader  {
      public:
        int   id;
        int   num_vertices;
        int   bp1, bp2;
        int   signal_process_id;
        int   signal_process_vertex;
        float scale;
        float alpha_qcd;
        float alpha_qed;
        std::vector<float>      weights;
        std::vector<long>       random;
        EventHeader() : id(0), num_vertices(0), bp1(0), bp2(0), 
                        signal_process_id(0), signal_process_vertex(0),
                        scale(0.0), alpha_qcd(0.0), alpha_qed(0.0), weights(), random() {}
      };
 
      enum known_io { gen=1, ascii, extascii, ascii_pdt, extascii_pdt };
 
      /*
       *  \author  P.Kostka (main author)
       *  \author  M.Frank  (code reshuffeling into new DDG4 scheme)
       *  \version 1.0
       *  \ingroup DD4HEP_SIMULATION
       */
      class EventStream {
      public:
        typedef std::map<int,Geant4Vertex*> Vertices;
        typedef std::map<int,Geant4Particle*> Particles;
 
        std::istream& instream;
 
        // io information
        std::string key;
        double mom_unit, pos_unit;
        int    io_type;
 
        float  xsection, xsection_err;
        EventHeader header;
        Vertices m_vertices;
        Particles m_particles;
 
        EventStream(std::istream& in) : instream(in), mom_unit(0.0), pos_unit(0.0),
                                   io_type(0), xsection(0.0), xsection_err(0.0)
        { use_default_units();                       }
        bool ok()  const;
        Geant4Vertex* vertex(int i);
        Particles& particles() { return m_particles; }
        Vertices&  vertices()  { return m_vertices;  }
        void set_io(int typ, const std::string& k)
        { io_type = typ;    key = k;                 }
        void use_default_units()
        { mom_unit = CLHEP::MeV;   pos_unit = CLHEP::mm;           }
        bool read();
        void clear();
      };
 
      char get_input(std::istream& is, std::istringstream& iline);
      int read_until_event_end(std::istream & is);
      int read_weight_names(EventStream &, std::istringstream& iline);
      int read_particle(EventStream &info, std::istringstream& iline, Geant4Particle * p);
      int read_vertex(EventStream &info, std::istream& is, std::istringstream & iline);
      int read_event_header(EventStream &info, std::istringstream & input, EventHeader& header);
      int read_cross_section(EventStream &info, std::istringstream & input);
      int read_units(EventStream &info, std::istringstream & input);
      int read_heavy_ion(EventStream &, std::istringstream & input);
      int read_pdf(EventStream &, std::istringstream & input);
      Geant4Vertex* vertex(EventStream& info, int i);
      void fix_particles(EventStream &info);
    }
  }
}
 
// For debugging specify here vertex numbers
//#define DD4HEP_DEBUG_HEP_MC_VERTEX   -390
//#define DD4HEP_DEBUG_HEP_MC_PARTICLE 418
 
Geant4EventReaderHepMC::Geant4EventReaderHepMC(const std::string& nam)
  : Geant4EventReader(nam), m_input(), m_events(0)
{
  // Now open the input file:
  m_input.open(nam.c_str(), BOOST_IOS::in|BOOST_IOS::binary);
  if ( not m_input.is_open() )   {
    except("+++ Failed to open input stream: %s Error:%s.", nam.c_str(), ::strerror(errno));
  }
  m_events = new HepMC::EventStream(m_input);
}
 
Geant4EventReaderHepMC::~Geant4EventReaderHepMC()    {
  delete m_events;
  m_events = 0;
  m_input.close();
}
 
Geant4EventReader::EventReaderStatus
Geant4EventReaderHepMC::moveToEvent(int event_number) {
  if( m_currEvent < event_number && event_number != 0 ) {
    printout(INFO,"EventReaderHepMC::moveToEvent","Current event:%d Skipping the next %d events",
             m_currEvent, event_number);
    while ( m_currEvent < event_number ) {
      if ( not m_events->read() ) return EVENT_READER_ERROR;
      ++m_currEvent;
    }
  }
  printout(DEBUG,"EventReaderHepMC::moveToEvent","Current event number: %d",m_currEvent);
  return EVENT_READER_OK;
}
 
Geant4EventReaderHepMC::EventReaderStatus
Geant4EventReaderHepMC::readParticles(int /* ev_id */,
                                      Vertices&  vertices,
                                      Particles& output) {
 
  //fg: for now we create exactly one event vertex here ( as before )
  //    this needs revisiting as HepMC allows to have more than one vertex ...
  Geant4Vertex* primary_vertex = new Geant4Vertex ;
  vertices.emplace_back( primary_vertex );
  primary_vertex->x = 0;
  primary_vertex->y = 0;
  primary_vertex->z = 0;
 
  if ( !m_events->ok() )  {
    vertices.clear();
    output.clear();
    return EVENT_READER_EOF;
  }
  else if ( m_events->read() )  {
    EventStream::Particles& parts = m_events->particles();
 
    Position pos(primary_vertex->x,primary_vertex->y,primary_vertex->z);
 
    output.reserve(parts.size());
    transform(parts.begin(),parts.end(),back_inserter(output),detail::reference2nd(parts));
    m_events->clear();
    if (pos.mag2() > std::numeric_limits<double>::epsilon() )  {
      for(Particles::iterator k=output.begin(); k != output.end(); ++k) {
        Geant4ParticleHandle p(*k);
        p->vsx += pos.x();
        p->vsy += pos.y();
        p->vsz += pos.z();
        p->vex += pos.x();
        p->vey += pos.y();
        p->vez += pos.z();
      }
    }
    for(Particles::const_iterator k=output.begin(); k != output.end(); ++k) {
      Geant4ParticleHandle p(*k);
      printout(VERBOSE,m_name,
               "+++ %s ID:%3d status:%08X typ:%9d Mom:(%+.2e,%+.2e,%+.2e)[MeV] "
               "time: %+.2e [ns] #Dau:%3d #Par:%1d",
               "",p->id,p->status,p->pdgID,
               p->psx/CLHEP::MeV,p->psy/CLHEP::MeV,p->psz/CLHEP::MeV,p->time/CLHEP::ns,
               p->daughters.size(),
               p->parents.size());
      //output.emplace_back(p);
 
      //add particles to the 'primary vertex'
      if ( p->parents.size() == 0 )  {
        PropertyMask status(p->status);
        if ( status.isSet(G4PARTICLE_GEN_EMPTY) || status.isSet(G4PARTICLE_GEN_DOCUMENTATION) )
          primary_vertex->in.insert(p->id);  // Beam particles and primary quarks etc.
        else
          primary_vertex->out.insert(p->id); // Stuff, to be given to Geant4 together with daughters
      }
    }
    ++m_currEvent;
    return EVENT_READER_OK;
  }
  vertices.clear();
  output.clear();
  return EVENT_READER_EOF;
}
 
void HepMC::fix_particles(EventStream& info)  {
  EventStream::Particles& parts = info.particles();
  EventStream::Vertices&  verts = info.vertices();
  EventStream::Particles::iterator i;
  std::set<int>::const_iterator id, ip;
  for(i=parts.begin(); i != parts.end(); ++i)  {
    Geant4ParticleHandle p((*i).second);
    int end_vtx_id = p->secondaries;
    p->secondaries = 0;
    Geant4Vertex* v = vertex(info,end_vtx_id);
#if defined(DD4HEP_DEBUG_HEP_MC_VERTEX)
    if ( end_vtx_id == DD4HEP_DEBUG_HEP_MC_VERTEX )   {
      std::cout << "End-vertex:" << end_vtx_id << std::endl;
    }
#endif
    if ( v )   {
      p->vex = v->x;
      p->vey = v->y;
      p->vez = v->z;
      v->in.insert(p->id);
      for(id=v->out.begin(); id!=v->out.end();++id)    {
        EventStream::Particles::iterator ipp = parts.find(*id);
        Geant4Particle* dau = ipp != parts.end() ? (*ipp).second : 0;
        if ( !dau )
          std::cout << "ERROR: Invalid daughter particle: " << *id << std::endl;
        else
          dau->parents.insert(p->id);
        p->daughters.insert(*id);
      }
    }
  }
  for(const auto& iv : verts)   {
    Geant4Vertex* v = iv.second;
    for (int pout : v->out)   {
      EventStream::Particles::iterator ipp = parts.find(pout);
      if ( ipp != parts.end() )  {
        Geant4Particle* p = (*ipp).second;
        for (int d : v->in)   {
          p->parents.insert(d);
        }
      }
    }
  }
  std::vector<Geant4Particle*> beam;
  for(const auto& ipart : parts)   {
    Geant4ParticleHandle p(ipart.second);
    if ( p->parents.size() == 0 )  {
      for(int d : p->daughters)   {
        Geant4Particle *pp = parts[d];
        beam.emplace_back(pp);
      }
    }
  }
  for(auto* ipp : beam)   {
    //std::cout << "Clear parents of " << (*ipp)->id << std::endl;
    ipp->parents.clear();
    ipp->status = G4PARTICLE_GEN_DECAYED;
  }
}
 
Geant4Vertex* HepMC::vertex(EventStream& info, int i)   {
  EventStream::Vertices::iterator it=info.vertices().find(i);
  return (it==info.vertices().end()) ? 0 : (*it).second;
}
 
char HepMC::get_input(std::istream& is, std::istringstream& iline)  {
  char value = is.peek();
  if ( !is ) {        // make sure the stream is valid
    std::cerr << "StreamHelpers: setting badbit." << std::endl;
    is.clear(std::ios::badbit);
    return -1;
  }
  std::string line, firstc;
  getline(is,line);
  if ( !is ) {        // make sure the stream is valid
    std::cerr << "StreamHelpers: setting badbit." << std::endl;
    is.clear(std::ios::badbit);
    return -1;
  }
  iline.clear();
  iline.str(line);
  if ( line.length()>0 && line[1] == ' ' ) iline >> firstc;
  return iline ? value : -1;
}
 
int HepMC::read_until_event_end(std::istream & is) {
  std::string line;
  while ( is ) {
    char val = is.peek();
    if( val == 'E' ) {  // next event
      return 1;
    }
    getline(is,line);
    if ( !is.good() ) return 0;
  }
  return 0;
}
 
int HepMC::read_weight_names(EventStream&, std::istringstream&)   {
#if 0
  int HepMC::read_weight_names(EventStream& info, std::istringstream& iline)
    size_t name_size = 0;
  iline >> name_size;
  info.weights.names.clear();
  info.weights.weights.clear();
 
  std::string name;
  WeightContainer namedWeight;
  std::string::size_type i1 = line.find("\""), i2, len = line.size();
  for(size_t ii = 0; ii < name_size; ++ii) {
    // weight names may contain blanks
    if(i1 >= len) {
      std::cout << "debug: attempting to read past the end of the named weight line " << std::endl;
      std::cout << "debug: We should never get here" << std::endl;
      std::cout << "debug: Looking for the end of this event" << std::endl;
      read_until_event_end(is);
    }
    i2 = line.find("\"",i1+1);
    name = line.substr(i1+1,i2-i1-1);
    if ( namedWeight.names.find(name) == namedWeight.names.end() )
      namedWeight.names[name] = namedWeight.names.size();
    namedWeight.weights[ii] = info.weights.weights[ii];
    i1 = line.find("\"",i2+1);
  }
 
  info.weights.weights = namedWeight.weights;
  info.weights.names   = namedWeight.names;
#endif
  return 1;
}
 
int HepMC::read_particle(EventStream &info, std::istringstream& input, Geant4Particle * p)   {
  float ene = 0., theta = 0., phi = 0;
  int   size = 0, stat=0;
  PropertyMask status(p->status);
 
  // check that the input stream is still OK after reading item
  input >> p->id >> p->pdgID >> p->psx >> p->psy >> p->psz >> ene;
  p->id = info.particles().size();
#if defined(DD4HEP_DEBUG_HEP_MC_PARTICLE)
  if ( p->id == DD4HEP_DEBUG_HEP_MC_PARTICLE )   {
    std::cout << "Particle id: " << p->id << std::endl;
  }
#endif
  p->charge = 0;
  p->psx *= info.mom_unit;
  p->psy *= info.mom_unit;
  p->psz *= info.mom_unit;
  ene *= info.mom_unit;
  if ( !input )
    return 0;
  else if ( info.io_type != ascii )  {
    input >> p->mass;
    p->mass *= info.mom_unit;
  }
  else   {
    p->mass = std::sqrt(fabs(ene*ene - (p->psx*p->psx + p->psy*p->psy + p->psz*p->psz)));
  }
  // Reuse here the secondaries to store the end-vertex ID
  input >> stat >> theta >> phi >> p->secondaries >> size;
  if( !input )   {
    return 0;
  }
  //
  //  Generator status
  //  Simulator status 0 until simulator acts on it
  status.clear();
  if ( stat == 0 )        status.set(G4PARTICLE_GEN_EMPTY);
  else if ( stat == 0x1 ) status.set(G4PARTICLE_GEN_STABLE);
  else if ( stat == 0x2 ) status.set(G4PARTICLE_GEN_DECAYED);
  else if ( stat == 0x3 ) status.set(G4PARTICLE_GEN_DOCUMENTATION);
  else if ( stat == 0x4 ) status.set(G4PARTICLE_GEN_DOCUMENTATION);
  else if ( stat == 0xB ) status.set(G4PARTICLE_GEN_DOCUMENTATION);
  else                    status.set(G4PARTICLE_GEN_OTHER);
  if ( p->secondaries != 0 )  {
    status.set(G4PARTICLE_GEN_DECAYED);
  }
  p->genStatus = stat&G4PARTICLE_GEN_STATUS_MASK;
  
  // read flow patterns if any exist. Protect against tainted readings.
  size = std::min(size,100);
  for (int i = 0; i < size; ++i ) {
    input >> p->colorFlow[0] >> p->colorFlow[1];
    if(!input) return 0;
  }
  return 1;
}
 
int HepMC::read_vertex(EventStream &info, std::istream& is, std::istringstream & input)    {
  int id=0, dummy = 0, num_orphans_in=0, num_particles_out=0, weights_size=0;
  std::vector<float> weights;
  Geant4Vertex* v = new Geant4Vertex();
  Geant4Particle* p;
 
  if( !input ) {
    delete v;
    return 0;
  }
  input >> id >> dummy >> v->x >> v->y >> v->z >> v->time
        >> num_orphans_in >> num_particles_out >> weights_size;
  if( !input ) {
    delete v;
    return 0;
  }
  if ( weights_size < 0 || weights_size > USHRT_MAX )  {
    delete v;
    return 0;
  }
#if defined(DD4HEP_DEBUG_HEP_MC_VERTEX)
  if ( id == DD4HEP_DEBUG_HEP_MC_VERTEX )   {
    printout(ALWAYS,"HepMC","++ Created Vertex ID=%d",id);
  }
#endif
  v->x *= info.pos_unit;
  v->y *= info.pos_unit;
  v->z *= info.pos_unit;
  for (int i1 = 0; i1 < weights_size; ++i1) {
    float value = 0e0;
    input >> value;
    weights.emplace_back(value);
    if( !input ) {
      delete v;
      return 0;
    }
  }
  info.vertices().emplace(id,v);
  for(char value = is.peek(); value=='P'; value=is.peek())  {
    value = get_input(is,input);
    if( !input || value < 0 )
      return 0;
 
    read_particle(info, input,p = new Geant4Particle());
    if( !input )   {
      printout(ERROR,"HepMC","++ Vertex %d Failed to daughter read particle!",id);
      delete p;
      return 0;
    }
    info.particles().emplace(p->id,p);
    p->pex = p->psx;
    p->pey = p->psy;
    p->pez = p->psz;
    if ( --num_orphans_in >= 0 )   {
      v->in.insert(p->id);
      p->vex = v->x;
      p->vey = v->y;
      p->vez = v->z;
#if defined(DD4HEP_DEBUG_HEP_MC_VERTEX)
      if ( id == DD4HEP_DEBUG_HEP_MC_VERTEX )   {
        printout(ALWAYS,"HepMC","++ Vertex %d Add INGOING  Particle: %d",id,p->id);
      }
#endif
    }
    else if ( num_particles_out >= 0 )   {
      v->out.insert(p->id);
      p->vsx = v->x;
      p->vsy = v->y;
      p->vsz = v->z;
#if defined(DD4HEP_DEBUG_HEP_MC_VERTEX)
      if ( id == DD4HEP_DEBUG_HEP_MC_VERTEX )   {
        printout(ALWAYS,"HepMC","++ Vertex %d Add OUTGOING Particle: %d",id,p->id);
      }
#endif
    }
    else  {
      delete p;
      except("HepMC", "Invalid number of particles....");
    }
  }
  return 1;
}
 
int HepMC::read_event_header(EventStream &info, std::istringstream & input, EventHeader& header)   {
  // read values into temp variables, then fill GenEvent
  int size = 0;
  input >> header.id;
  if( info.io_type == gen || info.io_type == extascii ) {
    int nmpi = -1;
    input >> nmpi;
    if( input.fail() ) return 0;
    //MSF set_mpi( nmpi );
  }
  input >> header.scale;
  input >> header.alpha_qcd;
  input >> header.alpha_qed;
  input >> header.signal_process_id;
  input >> header.signal_process_vertex;
  input >> header.num_vertices;
  if( info.io_type == gen || info.io_type == extascii )
    input >> header.bp1 >> header.bp2;
 
  printout(DEBUG,"HepMC","++ Event header: %s",input.str().c_str());
  input >> size;
  input.clear();
  if( input.fail() )
    return 0;
  if( size < 0 || size > USHRT_MAX )
    return 0;
  
  for(int i = 0; i < size; ++i )  {
    long val = 0e0;
    input >> val;
    header.random.emplace_back(val);
    if( input.fail() ) return 0;
  }
 
  input >> size;
  if( input.fail() )
    return 0;
  if( size < 0 || size > USHRT_MAX )
    return 0;
 
  std::vector<float> wgt;
  for( int ii = 0; ii < size; ++ii )  {
    float val = 0e0;
    input >> val;
    wgt.emplace_back(val);
    if( input.fail() ) return 0;
  }
  // weight names will be added later if they exist
  if( !wgt.empty() ) header.weights = std::move(wgt);
  return 1;
}
 
int HepMC::read_cross_section(EventStream &info, std::istringstream & input)   {
  input >> info.xsection >> info.xsection_err;
  return input.fail() ? 0 : 1;
}
 
int HepMC::read_units(EventStream &info, std::istringstream & input)   {
  if( info.io_type == gen )  {
    std::string mom, pos;
    input >> mom >> pos;
    if ( !input.fail() )  {
      if ( mom == "KEV" ) info.mom_unit = CLHEP::keV;
      else if ( mom == "MEV" ) info.mom_unit = CLHEP::MeV;
      else if ( mom == "GEV" ) info.mom_unit = CLHEP::GeV;
      else if ( mom == "TEV" ) info.mom_unit = CLHEP::TeV;
 
      if ( pos == "MM" ) info.pos_unit = CLHEP::mm;
      else if ( pos == "CM" ) info.pos_unit = CLHEP::cm;
      else if ( pos == "M"  ) info.pos_unit = CLHEP::m;
    }
  }
  return input.fail() ? 0 : 1;
}
 
int HepMC::read_heavy_ion(EventStream &, std::istringstream & input)  {
  // read values into temp variables, then create a new HeavyIon object
  int nh =0, np =0, nt =0, nc =0,
    neut = 0, prot = 0, nw =0, nwn =0, nwnw =0;
  float impact = 0., plane = 0., xcen = 0., inel = 0.;
  input >> nh >> np >> nt >> nc >> neut >> prot >> nw >> nwn >> nwnw;
  input >> impact >> plane >> xcen >> inel;
  /*
    std::cerr << "Reading heavy ion, but igoring data!" << std::endl;
    ion->set_Ncoll_hard(nh);
    ion->set_Npart_proj(np);
    ion->set_Npart_targ(nt);
    ion->set_Ncoll(nc);
    ion->set_spectator_neutrons(neut);
    ion->set_spectator_protons(prot);
    ion->set_N_Nwounded_collisions(nw);
    ion->set_Nwounded_N_collisions(nwn);
    ion->set_Nwounded_Nwounded_collisions(nwnw);
    ion->set_impact_parameter(impact);
    ion->set_event_plane_angle(plane);
    ion->set_eccentricity(xcen);
    ion->set_sigma_inel_NN(inel);
  */
  return input.fail() ? 0 : 1;
}
 
int HepMC::read_pdf(EventStream &, std::istringstream & input)  {
  // read values into temp variables, then create a new PdfInfo object
  int id1 =0, id2 =0;
  double  x1 = 0., x2 = 0., scale = 0., pdf1 = 0., pdf2 = 0.;
  input >> id1 ;
  if ( input.fail()  )
    return 0;
  // check now for empty PdfInfo line
  if( id1 == 0 )
    return 0;
  // continue reading
  input >> id2 >> x1 >> x2 >> scale >> pdf1 >> pdf2;
  if ( input.fail()  )
    return 0;
  /*
    std::cerr << "Reading pdf, but igoring data!" << std::endl;
    pdf->set_id1( id1 );
    pdf->set_id2( id2 );
    pdf->set_x1( x1 );
    pdf->set_x2( x2 );
    pdf->set_scalePDF( scale );
    pdf->set_pdf1( pdf1 );
    pdf->set_pdf2( pdf2 );
  */
  // check to see if we are at the end of the line
  if( !input.eof() )  {
    int pdf_id1=0, pdf_id2=0;
    input >> pdf_id1 >> pdf_id2;
    /*
      pdf->set_pdf_id1( pdf_id1 );
      pdf->set_pdf_id2( pdf_id2 );
    */
  }
  return input.fail() ? 0 : 1;
}
 
bool HepMC::EventStream::ok()  const   {
  // make sure the stream is good
  if ( instream.eof() || instream.fail() )  {
    instream.clear(std::ios::badbit);
    return false;
  }
  return true;
}
 
void HepMC::EventStream::clear()   {
  detail::releaseObjects(m_vertices);
  detail::releaseObjects(m_particles);
}
 
bool HepMC::EventStream::read()   {
  EventStream& info = *this;
  bool event_read = false;
 
  detail::releaseObjects(vertices());
  detail::releaseObjects(particles());
 
  while( instream.good() ) {
    char value = instream.peek();
    std::istringstream input_line;
    if      ( value == 'E' && event_read )
      break;
    else if ( instream.eof() && event_read )
      goto Done;
    else if ( instream.eof() )
      return false;
    else if ( value=='#' || ::isspace(value) )  {
      get_input(instream,input_line);
      continue;
    }
    value = get_input(instream,input_line);
 
    // On failure switch to end
    if( !input_line || value < 0 )
      goto Skip;
 
    switch( value )   {
    case 'H':  {
      int iotype = 0;
      std::string key_value;
      input_line >> key_value;
      // search for event listing key before first event only.
      key_value = key_value.substr(0,key_value.find('\r'));
      if ( key_value == "H" && (this->io_type == gen || this->io_type == extascii) ) {
        read_heavy_ion(info, input_line);
        break;
      }
      else if( key_value == "HepMC::IO_GenEvent-START_EVENT_LISTING" )
        this->set_io(gen,key_value);
      else if( key_value == "HepMC::IO_Ascii-START_EVENT_LISTING" )
        this->set_io(ascii,key_value);
      else if( key_value == "HepMC::IO_ExtendedAscii-START_EVENT_LISTING" )
        this->set_io(extascii,key_value);
      else if( key_value == "HepMC::IO_Ascii-START_PARTICLE_DATA" )
        this->set_io(ascii_pdt,key_value);
      else if( key_value == "HepMC::IO_ExtendedAscii-START_PARTICLE_DATA" )
        this->set_io(extascii_pdt,key_value);
      else if( key_value == "HepMC::IO_GenEvent-END_EVENT_LISTING" )
        iotype = gen;
      else if( key_value == "HepMC::IO_Ascii-END_EVENT_LISTING" )
        iotype = ascii;
      else if( key_value == "HepMC::IO_ExtendedAscii-END_EVENT_LISTING" )
        iotype = extascii;
      else if( key_value == "HepMC::IO_Ascii-END_PARTICLE_DATA" )
        iotype = ascii_pdt;
      else if( key_value == "HepMC::IO_ExtendedAscii-END_PARTICLE_DATA" )
        iotype = extascii_pdt;
 
      if( iotype != 0 && this->io_type != iotype )  {
        std::cerr << "GenEvent::find_end_key: iotype keys have changed. "
                  << "MALFORMED INPUT" << std::endl;
        instream.clear(std::ios::badbit);
        return false;
      }
      else if ( iotype != 0 )  {
        break;
      }
      continue;
    }
    case 'E':           // deal with the event line
      if ( !read_event_header(info, input_line, this->header) )
        goto Skip;
      event_read = true;
      continue;
 
    case 'N':           // get weight names
      if ( !read_weight_names(info, input_line) )
        goto Skip;
      continue;
 
    case 'U':           // get unit information if it exists
      if ( !read_units(info, input_line) )
        goto Skip;
      continue;
 
    case 'C':           // we have a GenCrossSection line
      if ( !read_cross_section(info, input_line) )
        goto Skip;
      continue;
 
    case 'V':           // Read vertex with particles
      if ( !read_vertex(info, instream, input_line) )
        goto Skip;
      continue;
 
    case 'F':           // Read PDF
      if ( !read_pdf(info, input_line) )
        goto Skip;
      continue;
 
    case 'P':           // we should not find this line
      std::cerr << "streaming input: found unexpected Particle line." << std::endl;
      continue;
 
    default:            // ignore everything else
      continue;
    }
    continue;
  Skip:
    printout(WARNING,"HepMC::EventStream","+++ Skip event with ID: %d",this->header.id);
    detail::releaseObjects(vertices());
    detail::releaseObjects(particles());
    read_until_event_end(instream);
    event_read = false;
    if ( instream.eof() ) return false;
  }
 
  if( not instream.good() ) return false;
 Done:
  fix_particles(info);
  detail::releaseObjects(vertices());
  return true;
}