storageSizeForBranch.cc File Reference

#include <iostream>
#include <boost/program_options.hpp>
#include "TClass.h"
#include "TFile.h"
#include "TBranch.h"
#include "TBufferFile.h"
#include "TTree.h"
#include "FWCore/FWLite/interface/FWLiteEnabler.h"
#include "FWCore/Utilities/interface/Exception.h"

Go to the source code of this file.

Functions
int	main (int argc, char *argv[])

Variables
static char const *const	kBranchNameOpt = "branchName"
static char const *const	kEntryNumberCommandOpt = "entryNumber,e"
static char const *const	kEntryNumberOpt = "entryNumber"
static char const *const	kFileNameOpt = "fileName"
static char const *const	kHelpCommandOpt = "help,h"
static char const *const	kHelpOpt = "help"

Function Documentation

int main	(	int	argc,
		char *	argv[]
	)

Definition at line 36 of file storageSizeForBranch.cc.

References MicroEventContent_cff::branch, electrons_cff::branchName, MessageLogger_cfi::cerr, gather_cfg::cout, MillePedeFileConverter_cfg::e, FWLiteEnabler::enable(), relativeConstraints::error, cppFunctionSkipper::exception, cms::Exception::explainSelf(), FrontierConditions_GlobalTag_cff::file, MillePedeFileConverter_cfg::fileName, kBranchNameOpt, kEntryNumberCommandOpt, kEntryNumberOpt, kFileNameOpt, kHelpCommandOpt, kHelpOpt, AlcaSiPixelAliHarvester0T_cff::options, AlCaHLTBitMon_ParallelJobs::p, writedatasetfile::run, AlCaHLTBitMon_QueryRunRegistry::string, and cms::Exception::what().

                                     {
  std::string descString(argv[0]);
  descString += " [options] [--";
  descString += kBranchNameOpt;
  descString += "] branch_name [--";
  descString += kFileNameOpt;
  descString +=
      "] file_name"
      "\n The program dumps information about how much storage space is needed to store a given TBranch within a ROOT "
      "file"
      "\nAllowed options";
  boost::program_options::options_description desc(descString);
  desc.add_options()(kHelpCommandOpt, "show this help message")(kEntryNumberCommandOpt,
                                                                boost::program_options::value<int>(),
                                                                "read branch from the given entry value (default 0)")(
      kBranchNameOpt, "name of branch")(kFileNameOpt, "name of file");

  boost::program_options::positional_options_description p;
  p.add(kBranchNameOpt, 1);
  p.add(kFileNameOpt, 1);

  boost::program_options::variables_map vm;
  try {
    store(boost::program_options::command_line_parser(argc, argv).options(desc).positional(p).run(), vm);
    notify(vm);
  } catch (boost::program_options::error const& iException) {
    std::cerr << "failed to parse command line \n" << iException.what() << "\n";
    return 1;
  }

  if (vm.count(kHelpOpt)) {
    std::cout << desc << std::endl;
    return 0;
  }
  int entryNumber = 0;
  if (vm.count(kEntryNumberOpt)) {
    entryNumber = vm[kEntryNumberOpt].as<int>();
  }

  if (!vm.count(kBranchNameOpt)) {
    std::cerr << "no branch name given\n";
    return 1;
  }

  if (!vm.count(kFileNameOpt)) {
    std::cerr << "no branch name given\n";
    return 1;
  }

  std::string branchName(vm[kBranchNameOpt].as<std::string>());
  std::string fileName(vm[kFileNameOpt].as<std::string>());

  TFile* file = TFile::Open(fileName.c_str());
  if (nullptr == file) {
    std::cerr << "failed to open '" << fileName << "'";
    return 1;
  }

  TTree* eventTree = dynamic_cast<TTree*>(file->Get("Events"));

  if (nullptr == eventTree) {
    std::cerr << "The file '" << fileName << "' does not contain an 'Events' TTree";
    return 1;
  }

  TBranch* branch = eventTree->GetBranch(branchName.c_str());

  if (nullptr == branch) {
    std::cerr << "The Events TTree does not contain the branch " << branchName;
    return 1;
  }

  FWLiteEnabler::enable();

  TClass* cls = TClass::GetClass(branch->GetClassName());
  if (nullptr == cls) {
    std::cerr << "class '" << branch->GetClassName() << "' is unknown by ROOT\n";
    return 1;
  }

  void* objInstance = cls->New();
  if (nullptr == objInstance) {
    std::cerr << "unable to create a default instance of the class " << branch->GetClassName();
    return 1;
  }

  //associate this with the branch
  void* pObjInstance = &objInstance;

  branch->SetAddress(pObjInstance);

  branch->GetEntry(entryNumber);

  TBufferFile bf(TBuffer::kWrite);

  gDebug = 3;
  cls->WriteBuffer(bf, objInstance);

  gDebug = 0;
  std::cout << "Total amount stored: " << bf.Length() << " bytes" << std::endl;
  std::cout << "\nNOTE: add 4 bytes for each 'has written' value because of a bug in ROOT's printout of the accounting"
            << "\n  Each class (inheriting or as member data) has metadata an overhead of 10 bytes" << std::endl;
  return 0;
} catch (cms::Exception const& e) {
  std::cerr << e.explainSelf() << std::endl;
  return 1;
} catch (std::exception const& e) {
  std::cerr << e.what() << std::endl;
  return 1;
}

Variable Documentation

char const* const kBranchNameOpt = "branchName"

static

Definition at line 29 of file storageSizeForBranch.cc.

Referenced by main().

char const* const kEntryNumberCommandOpt = "entryNumber,e"

static

Definition at line 33 of file storageSizeForBranch.cc.

Referenced by main().

char const* const kEntryNumberOpt = "entryNumber"

static

Definition at line 34 of file storageSizeForBranch.cc.

Referenced by main().

char const* const kFileNameOpt = "fileName"

static

Definition at line 30 of file storageSizeForBranch.cc.

Referenced by main().

char const* const kHelpCommandOpt = "help,h"

static

Definition at line 32 of file storageSizeForBranch.cc.

Referenced by main().

char const* const kHelpOpt = "help"

static

Definition at line 31 of file storageSizeForBranch.cc.

Referenced by main().