HepMC Reference Documentation HepMC

IO_ExtendedAscii.cc

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//--------------------------------------------------------------------------

// garren@fnal.gov, July 2006
// event input/output in ascii format for machine reading
// extended format contains HeavyIon and PdfInfo classes

#include "HepMC/IO_ExtendedAscii.h"
#include "HepMC/GenEvent.h"
#include "HepMC/ParticleDataTable.h"
#include "HepMC/HeavyIon.h"
#include "HepMC/PdfInfo.h"
#include "HepMC/Version.h"

namespace HepMC {

    IO_ExtendedAscii::IO_ExtendedAscii( const char* filename, std::ios::openmode mode ) 
        : m_mode(mode), m_file(filename, mode), m_finished_first_event_io(0) 
    {
        if ( (m_mode&std::ios::out && m_mode&std::ios::in) ||
             (m_mode&std::ios::app && m_mode&std::ios::in) ) {
            std::cerr << "IO_ExtendedAscii::IO_ExtendedAscii Error, open of file requested "
                      << "of input AND output type. Not allowed. Closing file."
                      << std::endl;
            m_file.close();
            return;
        }
        // precision 16 (# digits following decimal point) is the minimum that
        //  will capture the full information stored in a double
        m_file.precision(16);
        // we use decimal to store integers, because it is smaller than hex!
        m_file.setf(std::ios::dec,std::ios::basefield);
        m_file.setf(std::ios::scientific,std::ios::floatfield);
    }

    IO_ExtendedAscii::~IO_ExtendedAscii() {
        write_end_listing();
        m_file.close();
    }

    void IO_ExtendedAscii::print( std::ostream& ostr ) const { 
        ostr << "IO_ExtendedAscii: unformated ascii file IO for machine reading.\n" 
             << "\tFile openmode: " << m_mode 
             << " file state: " << m_file.rdstate()
             << " bad:" << (m_file.rdstate()&std::ios::badbit)
             << " eof:" << (m_file.rdstate()&std::ios::eofbit)
             << " fail:" << (m_file.rdstate()&std::ios::failbit)
             << " good:" << (m_file.rdstate()&std::ios::goodbit) << std::endl;
    }

    void IO_ExtendedAscii::write_event( const GenEvent* evt ) {
        //
        // check the state of m_file is good, and that it is in output mode
        if ( !evt || !m_file ) return;
        if ( !m_mode&std::ios::out ) {
            std::cerr << "HepMC::IO_ExtendedAscii::write_event "
                      << " attempt to write to input file." << std::endl;
            return;
        }
        //
        // write event listing key before first event only.
        if ( !m_finished_first_event_io ) {
            m_finished_first_event_io = 1;
            m_file << "\n" << "HepMC::Version " << versionName();
            m_file << "\n" << "HepMC::IO_ExtendedAscii-START_EVENT_LISTING\n";
        }
        //
        // output the event data including the number of primary vertices
        //  and the total number of vertices
        std::vector<long int> random_states = evt->random_states();
        m_file << 'E';
        output( evt->event_number() );
        output( evt->mpi() );
        output( evt->event_scale() );
        output( evt->alphaQCD() );
        output( evt->alphaQED() );
        output( evt->signal_process_id() );
        output(   ( evt->signal_process_vertex() ?
                    evt->signal_process_vertex()->barcode() : 0 )   );
        output( evt->vertices_size() ); // total number of vertices.
        write_beam_particles( evt->beam_particles() );
        output( (int)random_states.size() );
        for ( std::vector<long int>::iterator rs = random_states.begin(); 
              rs != random_states.end(); ++rs ) {
            output( *rs );
        }
        output( (int)evt->weights().size() );
        for ( WeightContainer::const_iterator w = evt->weights().begin(); 
              w != evt->weights().end(); ++w ) {
            output( *w );
        }
        output('\n');
        write_heavy_ion( evt->heavy_ion() );
        write_pdf_info( evt->pdf_info() );
        //
        // Output all of the vertices - note there is no real order.
        for ( GenEvent::vertex_const_iterator v = evt->vertices_begin();
              v != evt->vertices_end(); ++v ) {
            write_vertex( *v );
        }
    }

    bool IO_ExtendedAscii::fill_next_event( GenEvent* evt ){
        //
        //
        // test that evt pointer is not null
        if ( !evt ) {
            std::cerr 
                << "IO_ExtendedAscii::fill_next_event error - passed null event." 
                << std::endl;
            return 0;
        }
        // check the state of m_file is good, and that it is in input mode
        if ( !m_file ) return 0;
        if ( !(m_mode&std::ios::in) ) {
            std::cerr << "HepMC::IO_ExtendedAscii::fill_next_event "
                      << " attempt to read from output file." << std::endl;
            return 0;
        }
        //
        // search for event listing key before first event only.
        //
        // skip through the file just after first occurence of the start_key
        if ( !m_finished_first_event_io ) {
            m_file.seekg( 0 ); // go to position zero in the file.
            if (!search_for_key_end( m_file,
                                     "HepMC::IO_ExtendedAscii-START_EVENT_LISTING\n")){
                std::cerr << "IO_ExtendedAscii::fill_next_event start key not found "
                          << "setting badbit." << std::endl;
                m_file.clear(std::ios::badbit); 
                return 0;
            }
            m_finished_first_event_io = 1;
        }
        //
        // test to be sure the next entry is of type "E" then ignore it
        if ( !m_file || m_file.peek()!='E' ) { 
            // if the E is not the next entry, then check to see if it is
            // the end event listing key - if yes, search for another start key
            if ( eat_key(m_file, "HepMC::IO_ExtendedAscii-END_EVENT_LISTING\n") ) {
                bool search_result = search_for_key_end(m_file,
                                      "HepMC::IO_ExtendedAscii-START_EVENT_LISTING\n");
                if ( !search_result ) {
                    // this is the only case where we set an EOF state
                    m_file.clear(std::ios::eofbit);
                    return 0;
                }
            } else {
                std::cerr << "IO_ExtendedAscii::fill_next_event end key not found "
                          << "setting badbit." << std::endl;
                m_file.clear(std::ios::badbit); 
                return 0;
            }
        } 
        m_file.ignore();
        // read values into temp variables, then create a new GenEvent
        int event_number = 0, signal_process_id = 0, signal_process_vertex = 0,
            num_vertices = 0, random_states_size = 0, weights_size = 0,
            nmpi = 0, bp1 = 0, bp2 = 0;
        double eventScale = 0, alpha_qcd = 0, alpha_qed = 0;
        m_file >> event_number >> nmpi >> eventScale >> alpha_qcd >> alpha_qed
               >> signal_process_id >> signal_process_vertex
               >> num_vertices >> bp1 >> bp2 >> random_states_size;
        std::vector<long int> random_states(random_states_size);
        for ( int i = 0; i < random_states_size; ++i ) {
            m_file >> random_states[i];
        }
        m_file >> weights_size;
        WeightContainer weights(weights_size);
        for ( int ii = 0; ii < weights_size; ++ii ) m_file >> weights[ii];
        m_file.ignore(2,'\n');
        // 
        // fill signal_process_id, event_number, weights, random_states
        evt->set_signal_process_id( signal_process_id );
        evt->set_event_number( event_number );
        evt->set_mpi( nmpi );
        evt->weights() = weights;
        evt->set_random_states( random_states );
        evt->set_event_scale( eventScale );
        evt->set_alphaQCD( alpha_qcd );
        evt->set_alphaQED( alpha_qed );
        // get HeavyIon and PdfInfo
        HeavyIon* ion = read_heavy_ion();
        if(ion) evt->set_heavy_ion( *ion );
        PdfInfo* pdf = read_pdf_info();
        if(pdf) evt->set_pdf_info( *pdf );
        //
        // the end vertices of the particles are not connected until
        //  after the event is read --- we store the values in a map until then
        TempParticleMap particle_to_end_vertex;
        //
        // read in the vertices
        for ( int iii = 1; iii <= num_vertices; ++iii ) {
            GenVertex* v = read_vertex(particle_to_end_vertex);
            evt->add_vertex( v );
        }
        // set the signal process vertex
        if ( signal_process_vertex ) {
            evt->set_signal_process_vertex( 
                evt->barcode_to_vertex(signal_process_vertex) );
        }
        //
        // last connect particles to their end vertices
        GenParticle* beam1(0);
        GenParticle* beam2(0);
        for ( std::map<int,GenParticle*>::iterator pmap 
                  = particle_to_end_vertex.order_begin(); 
              pmap != particle_to_end_vertex.order_end(); ++pmap ) {
            GenParticle* p =  pmap->second;
            int vtx = particle_to_end_vertex.end_vertex( p );
            GenVertex* itsDecayVtx = evt->barcode_to_vertex(vtx);
            if ( itsDecayVtx ) itsDecayVtx->add_particle_in( p );
            else {
                std::cerr << "IO_ExtendedAscii::fill_next_event ERROR particle points"
                          << "\n to null end vertex. " <<std::endl;
            }
            // also look for the beam particles
            if( p->barcode() == bp1 ) beam1 = p;
            if( p->barcode() == bp2 ) beam2 = p;
        }
        evt->set_beam_particles(beam1,beam2);
        return 1;
    }

    void IO_ExtendedAscii::write_comment( const std::string comment ) {
        // check the state of m_file is good, and that it is in output mode
        if ( !m_file ) return;
        if ( !m_mode&std::ios::out ) {
            std::cerr << "HepMC::IO_ExtendedAscii::write_comment "
                      << " attempt to write to input file." << std::endl;
            return;
        }
        // write end of event listing key if events have already been written
        write_end_listing();
        // insert the comment key before the comment
        m_file << "\n" << "HepMC::IO_ExtendedAscii-COMMENT\n";
        m_file << comment << std::endl;
    }

    void IO_ExtendedAscii::write_particle_data_table( const ParticleDataTable* pdt) {
        //
        // check the state of m_file is good, and that it is in output mode
        if ( !m_file ) return;
        if ( !m_mode&std::ios::out ) {
            std::cerr << "HepMC::IO_ExtendedAscii::write_particle_data_table "
                      << " attempt to write to input file." << std::endl;
            return;
        }
        // write end of event listing key if events have already been written
        write_end_listing();
        //
        m_file << "\n" << "HepMC::IO_ExtendedAscii-START_PARTICLE_DATA\n";
        for ( ParticleDataTable::const_iterator pd = pdt->begin(); 
              pd != pdt->end(); pd++ ) {
            write_particle_data( pd->second );
        }
        m_file << "HepMC::IO_ExtendedAscii-END_PARTICLE_DATA\n" << std::flush;
    }

    bool IO_ExtendedAscii::fill_particle_data_table( ParticleDataTable* pdt ) {
        //
        // test that pdt pointer is not null
        if ( !pdt ) {
            std::cerr 
                << "IO_ExtendedAscii::fill_particle_data_table - passed null table." 
                << std::endl;
            return 0;
        }
        //
        // check the state of m_file is good, and that it is in input mode
        if ( !m_file ) return 0;
        if ( !m_mode&std::ios::in ) {
            std::cerr << "HepMC::IO_ExtendedAscii::fill_particle_data_table "
                      << " attempt to read from output file." << std::endl;
            return 0;
        }
        // position to beginning of file
        int initial_file_position = m_file.tellg();
        std::ios::iostate initial_state = m_file.rdstate();
        m_file.seekg( 0 );
        // skip through the file just after first occurence of the start_key
        if (!search_for_key_end( m_file,
                                 "HepMC::IO_ExtendedAscii-START_PARTICLE_DATA\n")) {
            m_file.seekg( initial_file_position );
            std::cerr << "IO_ExtendedAscii::fill_particle_data_table start key not  "
                      << "found setting badbit." << std::endl;
            m_file.clear(std::ios::badbit); 
            return 0;
        }
        //
        pdt->set_description("Read with IO_ExtendedAscii");
        // 
        // read Individual GenParticle data entries
        while ( read_particle_data( pdt ) );
        //
        // eat end_key
        if ( !eat_key(m_file,"HepMC::IO_ExtendedAscii-END_PARTICLE_DATA\n") ){
            std::cerr << "IO_ExtendedAscii::fill_particle_data_table end key not  "
                      << "found setting badbit." << std::endl;
            m_file.clear(std::ios::badbit);
        }
        // put the file back into its original state and position
        m_file.clear( initial_state );
        m_file.seekg( initial_file_position );
        return 1;
    }

    void IO_ExtendedAscii::write_vertex( GenVertex* v ) {
        // assumes mode has already been checked
        if ( !v || !m_file ) {
            std::cerr << "IO_ExtendedAscii::write_vertex !v||!m_file, "
                      << "v="<< v << " setting badbit" << std::endl;
            m_file.clear(std::ios::badbit); 
            return;
        }
        // First collect info we need
        // count the number of orphan particles going into v
        int num_orphans_in = 0;
        for ( GenVertex::particles_in_const_iterator p1
                  = v->particles_in_const_begin();
              p1 != v->particles_in_const_end(); ++p1 ) {
            if ( !(*p1)->production_vertex() ) ++num_orphans_in;
        }
        //
        m_file << 'V';
        output( v->barcode() ); // v's unique identifier
        output( v->id() );
        output( v->position().x() );
        output( v->position().y() );
        output( v->position().z() );
        output( v->position().t() );
        output( num_orphans_in );
        output( (int)v->particles_out_size() );
        output( (int)v->weights().size() );
        for ( WeightContainer::iterator w = v->weights().begin(); 
              w != v->weights().end(); ++w ) {
            output( *w );
        }
        output('\n');
        for ( GenVertex::particles_in_const_iterator p2 
                  = v->particles_in_const_begin();
              p2 != v->particles_in_const_end(); ++p2 ) {
            if ( !(*p2)->production_vertex() ) {
                write_particle( *p2 );
            }
        }
        for ( GenVertex::particles_out_const_iterator p3 
                  = v->particles_out_const_begin();
              p3 != v->particles_out_const_end(); ++p3 ) {
            write_particle( *p3 );
        }
    }

    void IO_ExtendedAscii::write_beam_particles( 
        std::pair<GenParticle *,GenParticle *> pr ) {
        GenParticle* p = pr.first;
        //m_file << 'B';
        if(!p) {
           output( 0 );
        } else {
           output( p->barcode() );
        }
        p = pr.second;
        if(!p) {
           output( 0 );
        } else {
           output( p->barcode() );
        }
    }

    void IO_ExtendedAscii::write_heavy_ion( HeavyIon* ion ) {
        // assumes mode has already been checked
        if ( !m_file ) {
            std::cerr << "IO_ExtendedAscii::write_heavy_ion !m_file, "
                      << " setting badbit" << std::endl;
            m_file.clear(std::ios::badbit); 
            return;
        }
        m_file << 'H';
        // HeavyIon* is set to 0 by default
        if ( !ion  ) {
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0 );
            output( 0. );
            output( 0. );
            output( 0. );
            output( 0. );
            output('\n');
            return;
        }
        //
        output( ion->Ncoll_hard() );
        output( ion->Npart_proj() );
        output( ion->Npart_targ() );
        output( ion->Ncoll() );
        output( ion->spectator_neutrons() );
        output( ion->spectator_protons() );
        output( ion->N_Nwounded_collisions() );
        output( ion->Nwounded_N_collisions() );
        output( ion->Nwounded_Nwounded_collisions() );
        output( ion->impact_parameter() );
        output( ion->event_plane_angle() );
        output( ion->eccentricity() );
        output( ion->sigma_inel_NN() );
        output('\n');
    }

    void IO_ExtendedAscii::write_pdf_info( PdfInfo* pdf ) {
        // assumes mode has already been checked
        if ( !m_file ) {
            std::cerr << "IO_ExtendedAscii::write_pdf_info !m_file, "
                      << " setting badbit" << std::endl;
            m_file.clear(std::ios::badbit); 
            return;
        }
        m_file << 'F';
        // PdfInfo* is set to 0 by default
        if ( !pdf ) {
            output( 0 );
            output( 0 );
            output( 0. );
            output( 0. );
            output( 0. );
            output( 0. );
            output( 0. );
            output('\n');
            return;
        }
        //
        output( pdf->id1() );
        output( pdf->id2() );
        output( pdf->x1() );
        output( pdf->x2() );
        output( pdf->scalePDF() );
        output( pdf->pdf1() );
        output( pdf->pdf2() );
        output('\n');
    }

    void IO_ExtendedAscii::write_particle( GenParticle* p ) {
        // assumes mode has already been checked
        if ( !p || !m_file ) {
            std::cerr << "IO_ExtendedAscii::write_particle !p||!m_file, "
                      << "v="<< p << " setting badbit" << std::endl;
            m_file.clear(std::ios::badbit); 
            return;
        }
        m_file << 'P';
        output( p->barcode() );
        output( p->pdg_id() );
        output( p->momentum().px() );
        output( p->momentum().py() );
        output( p->momentum().pz() );
        output( p->momentum().e() );
        output( p->generated_mass() );
        output( p->status() );
        output( p->polarization().theta() );
        output( p->polarization().phi() );
        // since end_vertex is oftentimes null, this CREATES a null vertex
        // in the map
        output(   ( p->end_vertex() ? p->end_vertex()->barcode() : 0 )  );
        m_file << ' ' << p->flow() << "\n";
    }

    void IO_ExtendedAscii::write_particle_data( const ParticleData* pdata ) {
        // assumes mode has already been checked
        if ( !pdata || !m_file ) {
            std::cerr << "IO_ExtendedAscii::write_particle_data !pdata||!m_file, "
                      << "pdata="<< pdata << " setting badbit" << std::endl;
            m_file.clear(std::ios::badbit); 
            return;
        }
        m_file << 'D';
        output( pdata->pdg_id() );
        output( pdata->charge() );
        output( pdata->mass() );
        output( pdata->clifetime() );
        output( (int)(pdata->spin()*2.+.1) );
        // writes the first 21 characters starting with 0
        m_file << " " << pdata->name().substr(0,21) << "\n";
    }

    GenVertex* IO_ExtendedAscii::read_vertex
    ( TempParticleMap& particle_to_end_vertex )
    {
        // assumes mode has already been checked
        //
        // test to be sure the next entry is of type "V" then ignore it
        if ( !m_file || m_file.peek()!='V' ) {
            std::cerr << "IO_ExtendedAscii::read_vertex setting badbit." << std::endl;
            m_file.clear(std::ios::badbit); 
            return 0;
        } 
        m_file.ignore();
        // read values into temp variables, then create a new GenVertex object
        int identifier =0, id =0, num_orphans_in =0, 
            num_particles_out = 0, weights_size = 0;
        double x = 0., y = 0., z = 0., t = 0.; 
        m_file >> identifier >> id >> x >> y >> z >> t
               >> num_orphans_in >> num_particles_out >> weights_size;
        WeightContainer weights(weights_size);
        for ( int i1 = 0; i1 < weights_size; ++i1 ) m_file >> weights[i1];
        m_file.ignore(2,'\n');
        GenVertex* v = new GenVertex( FourVector(x,y,z,t),
                                id, weights);
        v->suggest_barcode( identifier );
        //
        // read and create the associated particles. outgoing particles are
        //  added to their production vertices immediately, while incoming
        //  particles are added to a map and handles later.
        for ( int i2 = 1; i2 <= num_orphans_in; ++i2 ) {
            read_particle(particle_to_end_vertex);
        }
        for ( int i3 = 1; i3 <= num_particles_out; ++i3 ) {
            v->add_particle_out( read_particle(particle_to_end_vertex) );
        }
        return v;
    }

    HeavyIon* IO_ExtendedAscii::read_heavy_ion()
    {
        // assumes mode has already been checked
        //
        // test to be sure the next entry is of type "H" then ignore it
        if ( !m_file || m_file.peek()!='H' ) {
            std::cerr << "IO_ExtendedAscii::read_heavy_ion setting badbit." << std::endl;
            m_file.clear(std::ios::badbit); 
            return 0;
        } 
        m_file.ignore();
        // 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.; 
        m_file >> nh >> np >> nt >> nc >> neut >> prot
               >> nw >> nwn >> nwnw >> impact >> plane >> xcen >> inel;
        m_file.ignore(2,'\n');
        if( nh == 0 ) return 0;
        HeavyIon* ion = new HeavyIon(nh, np, nt, nc, neut, prot,
                                     nw, nwn, nwnw, 
                                     impact, plane, xcen, inel );
        //
        return ion;
    }

    PdfInfo* IO_ExtendedAscii::read_pdf_info()
    {
        // assumes mode has already been checked
        //
        // test to be sure the next entry is of type "F" then ignore it
        if ( !m_file || m_file.peek() !='F') {
            std::cerr << "IO_ExtendedAscii::read_pdf_info setting badbit." << std::endl;
            m_file.clear(std::ios::badbit); 
            return 0;
        } 
        m_file.ignore();
        // 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.; 
        m_file >> id1 >> id2 >> x1 >> x2 >> scale >> pdf1 >> pdf2;
        m_file.ignore(2,'\n');
        //std::cout << "read " << id1 << std::endl;
        if( id1 == 0 ) return 0;
        PdfInfo* pdf = new PdfInfo( id1, id2, x1, x2, scale, pdf1, pdf2);
        //
        return pdf;
    }

    GenParticle* IO_ExtendedAscii::read_particle(
        TempParticleMap& particle_to_end_vertex ){
        // assumes mode has already been checked
        //
        // test to be sure the next entry is of type "P" then ignore it
        if ( !m_file || m_file.peek()!='P' ) { 
            std::cerr << "IO_ExtendedAscii::read_particle setting badbit." 
                      << std::endl;
            m_file.clear(std::ios::badbit); 
            return 0;
        } 
        m_file.ignore();
        //
        // declare variables to be read in to, and read everything except flow
        double px = 0., py = 0., pz = 0., e = 0., m = 0., theta = 0., phi = 0.;
        int bar_code = 0, id = 0, status = 0, end_vtx_code = 0, flow_size = 0;
        m_file >> bar_code >> id >> px >> py >> pz >> e >> m >> status 
               >> theta >> phi >> end_vtx_code >> flow_size;
        //
        // read flow patterns if any exist
        Flow flow;
        int code_index, code;
        for ( int i = 1; i <= flow_size; ++i ) {
            m_file >> code_index >> code;
            flow.set_icode( code_index,code);
        }
        m_file.ignore(2,'\n'); // '\n' at end of entry
        GenParticle* p = new GenParticle( FourVector(px,py,pz,e), 
                                    id, status, flow, 
                                    Polarization(theta,phi) );
        p->set_generated_mass( m );
        p->suggest_barcode( bar_code );
        //
        // all particles are connected to their end vertex separately 
        // after all particles and vertices have been created - so we keep
        // a map of all particles that have end vertices
        if ( end_vtx_code != 0 ) {
            particle_to_end_vertex.addEndParticle(p,end_vtx_code);
        }
        return p;
    }

    ParticleData* IO_ExtendedAscii::read_particle_data( ParticleDataTable* pdt ) {
        // assumes mode has already been checked
        //
        // test to be sure the next entry is of type "D" then ignore it
        if ( !m_file || m_file.peek()!='D' ) return 0;
        m_file.ignore();
        //
        // read values into temp variables then create new ParticleData object
        char its_name[22];
        int its_id = 0, its_spin = 0;  
        double its_charge = 0, its_mass = 0, its_clifetime = 0;
        m_file >> its_id >> its_charge >> its_mass 
               >> its_clifetime >> its_spin;
        m_file.ignore(1); // eat the " "
        m_file.getline( its_name, 22, '\n' );
        ParticleData* pdata = new ParticleData( its_name, its_id, its_charge, 
                                                its_mass, its_clifetime, 
                                                double(its_spin)/2.);
        pdt->insert(pdata);
        return pdata;
    }

    bool IO_ExtendedAscii::write_end_listing() {
        if ( m_finished_first_event_io && m_mode&std::ios::out ) {
            m_file << "HepMC::IO_ExtendedAscii-END_EVENT_LISTING\n" << std::flush;
            m_finished_first_event_io = 0;
            return 1;
        }
        return 0;
    }

    bool IO_ExtendedAscii::search_for_key_end( std::istream& in, const char* key ) {
        // 
        char c[1];
        unsigned int index = 0;
        while ( in.get(c[0]) ) {
            if ( c[0] == key[index] ) { 
                ++index;
            } else { index = 0; }
            if ( index == strlen(key) ) return 1;
        }
        return 0;
    }

    bool IO_ExtendedAscii::search_for_key_beginning( std::istream& in,
                                             const char* key ) {
        if ( search_for_key_end( in, key) ) {
            int i = strlen(key);
            while ( i>=0 ) in.putback(key[i--]); 
            return 1; 
        } else {
            in.putback(EOF);
            in.clear();
            return 0;
        }
    }

    bool IO_ExtendedAscii::eat_key( std::iostream& in, const char* key ) {
        int key_length = strlen(key);
        // below is the only way I know of to get a variable length string
        //  conforming to ansi standard.
        char* c = new char[key_length +1];
        int i=0;
        // read the stream until get fails (because of EOF), a character
        //  doesn't match a character in the string, or all characters in
        //  the string have been checked and match.
        while ( in.get(c[i]) && c[i]==key[i] && i<key_length ) {
            ++i;
        }
        if ( i == key_length ) {
            delete [] c;
            return 1;
        }
        //
        // if we get here, then we have eaten the wrong this and we must put it
        // back
        while ( i>=0 ) in.putback(c[i--]); 
        delete c;
        return 0;
    }

    int IO_ExtendedAscii::find_in_map( const std::map<GenVertex*,int>& m, 
                               GenVertex* v ) const {
        std::map<GenVertex*,int>::const_iterator iter = m.find(v);
        if ( iter == m.end() ) return 0;
        return iter->second;
    }
        
} // HepMC

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