HepMC3 event record library
class_example_read.cc
1 // -*- C++ -*-
2 //
3 // This file is part of HepMC
4 // Copyright (C) 2014-2019 The HepMC collaboration (see AUTHORS for details)
5 //
6 /**
7  * @example class_example_read.cc
8  * @brief Basic example of use of root I/O: reading events from file
9  *
10  * @author Witold Pokorski
11  * @date 16/10/14
12  */
13 #include "HepMC3/GenEvent.h"
14 #include "HepMC3/GenRunInfo.h"
15 #include "HepMC3/WriterAscii.h"
16 #include "HepMC3/Print.h"
17 
18 #include "MyClass.h"
19 #include "MyRunClass.h"
20 
21 #include "TFile.h"
22 #include "TSystem.h"
23 #include "TKey.h"
24 
25 #include <iostream>
26 
27 using namespace HepMC3;
28 
29 
30 /** Main */
31 int main(int argc, char **argv) {
32 
33  if( argc<3 ) {
34  std::cout << "Usage: " << argv[0] << " <input_root_file> <output_hepmc3_file>" << std::endl;
35  exit(-1);
36  }
37 
38 
39  TFile fo(argv[1]);
40  WriterAscii text_output(argv[2]);
41 
42  MyClass* myevent;
43  int events_parsed = 0;
44 
45  // Get GenRunInfo, if available
46  MyRunClass *my_run = (MyRunClass*)fo.Get("MyRunClass");
47  std::shared_ptr<GenRunInfo> run_info;
48 
49  if( my_run ) run_info.reset(my_run->GetRunInfo());
50 
51 
52  fo.GetListOfKeys()->Print();
53 
54  TIter next(fo.GetListOfKeys());
55  TKey *key;
56 
57  while ((key=(TKey*)next()))
58  {
59  const char *cl = key->GetClassName();
60 
61  if( strncmp(cl,"MyClass",7) != 0 ) continue;
62 
63  fo.GetObject(key->GetName(), myevent);
64 
65  std::cout << "Event: " << key->GetName() << std::endl;
66 
67  if( events_parsed == 0 ) {
68  std::cout << "First event: " << std::endl;
69  Print::listing(*(myevent->GetEvent()));
70  }
71 
72  if( run_info ) {
73  std::cout << "Setting run info" << std::endl;
74  myevent->GetEvent()->set_run_info(run_info);
75  run_info.reset();
76  }
77 
78  text_output.write_event(*(myevent->GetEvent()));
79  ++events_parsed;
80 
81  if( events_parsed%100 == 0 ) {
82  std::cout << "Event: " << events_parsed << std::endl;
83  }
84 
85  delete myevent->GetEvent();
86  delete myevent;
87  }
88 
89  text_output.close();
90 
91  std::cout << "Events parsed and written: " << events_parsed << std::endl;
92 
93  return 0;
94 }
Definition of class GenRunInfo.
Sample class for root I/O test.
Definition: MyClass.h:9
Definition of class WriterAscii.
static void listing(std::ostream &os, const GenEvent &event, unsigned short precision=2)
Print event in listing (HepMC2) format.
Definition: Print.cc:50
Sample class for root I/O test.
Definition: MyRunClass.h:9
void set_run_info(std::shared_ptr< GenRunInfo > run)
Set the GenRunInfo object by smart pointer.
Definition: GenEvent.h:128
int main(int argc, char **argv)
GenRunInfo * GetRunInfo()
Get HepMC event.
Definition: MyRunClass.cc:10
Definition of class GenEvent.
GenEvent I/O serialization for structured text files.
Definition: WriterAscii.h:25
GenEvent * GetEvent()
Get HepMC event.
Definition: MyClass.cc:10