go-hep.org/x/hep@v0.38.1/groot/riofs/gendata/gen-base.go (about)

     1  // Copyright ©2022 The go-hep Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build ignore
     6  
     7  package main
     8  
     9  import (
    10  	"flag"
    11  	"log"
    12  
    13  	"go-hep.org/x/hep/groot/internal/rtests"
    14  )
    15  
    16  var (
    17  	root  = flag.String("f", "test-base.root", "output ROOT file")
    18  	split = flag.Int("split", 0, "default split-level for TTree")
    19  )
    20  
    21  func main() {
    22  	flag.Parse()
    23  
    24  	out, err := rtests.RunCxxROOT("gentree", []byte(script), *root, *split)
    25  	if err != nil {
    26  		log.Fatalf("could not run ROOT macro:\noutput:\n%v\nerror: %+v", string(out), err)
    27  	}
    28  }
    29  
    30  const script = `
    31  #include <stdint.h>
    32  
    33  class Base {
    34  public:
    35  	int32_t I32;
    36  };
    37  
    38  class D1 : public Base {
    39  public:
    40  	int32_t D32;
    41  };
    42  
    43  class D2 : public Base {
    44  public:
    45  	int32_t I32;
    46  };
    47  
    48  void gentree(const char* fname, int splitlvl = 99) {
    49  	int bufsize = 32000;
    50  	int evtmax = 2;
    51  
    52  	auto f = TFile::Open(fname, "RECREATE");
    53  	auto t = new TTree("tree", "my tree title");
    54  
    55  	D1 d1;
    56  	D2 d2;
    57  
    58  	t->Branch("d1", &d1, bufsize, splitlvl);
    59  	t->Branch("d2", &d2, bufsize, splitlvl);
    60  
    61  	for (int i = 0; i != evtmax; i++) {
    62  		d1.I32 = i+1;
    63  		d1.D32 = i+2;
    64  		((Base*)&d2)->I32 = i+3;
    65  		d2.I32 = i+4;
    66  
    67  		t->Fill();
    68  	}
    69  
    70  	f->Write();
    71  	f->Close();
    72  
    73  	exit(0);
    74  }
    75  `