FWLite/bin/storageSizeForBranch.cc

0001 // -*- C++ -*-
0002 //
0003 // Package:     FWLite
0004 // Class  :     storageSize
0005 //
0006 // Implementation:
0007 //     [Notes on implementation]
0008 //
0009 // Original Author:  Chris Jones
0010 //         Created:  Thu Jan 20 09:50:58 CST 2011
0011 //
0012
0013 // system include files
0014 #include <iostream>
0015 #include <boost/program_options.hpp>
0016 #include "TClass.h"
0017 #include "TFile.h"
0018 #include "TBranch.h"
0019 #include "TBufferFile.h"
0020 #include "TTree.h"
0021
0022 // user include files
0023 #include "FWCore/FWLite/interface/FWLiteEnabler.h"
0024 #include "FWCore/Utilities/interface/Exception.h"
0025
0026 //
0027 // constants, enums and typedefs
0028 //
0029 static char const* const kBranchNameOpt = "branchName";
0030 static char const* const kFileNameOpt = "fileName";
0031 static char const* const kHelpOpt = "help";
0032 static char const* const kHelpCommandOpt = "help,h";
0033 static char const* const kEntryNumberCommandOpt = "entryNumber,e";
0034 static char const* const kEntryNumberOpt = "entryNumber";
0035
0036 int main(int argc, char* argv[]) try {
0037   std::string descString(argv[0]);
0038   descString += " [options] [--";
0039   descString += kBranchNameOpt;
0040   descString += "] branch_name [--";
0041   descString += kFileNameOpt;
0042   descString +=
0043       "] file_name"
0044       "\n The program dumps information about how much storage space is needed to store a given TBranch within a ROOT "
0045       "file"
0046       "\nAllowed options";
0047   boost::program_options::options_description desc(descString);
0048   desc.add_options()(kHelpCommandOpt, "show this help message")(
0049       kEntryNumberCommandOpt,
0050       boost::program_options::value<int>(),
0051       "read branch from the given entry value (default 0)")(kBranchNameOpt, "name of branch")(kFileNameOpt,
0052                                                                                               "name of file");
0053
0054   boost::program_options::positional_options_description p;
0055   p.add(kBranchNameOpt, 1);
0056   p.add(kFileNameOpt, 1);
0057
0058   boost::program_options::variables_map vm;
0059   try {
0060     store(boost::program_options::command_line_parser(argc, argv).options(desc).positional(p).run(), vm);
0061     notify(vm);
0062   } catch (boost::program_options::error const& iException) {
0063     std::cerr << "failed to parse command line \n" << iException.what() << "\n";
0064     return 1;
0065   }
0066
0067   if (vm.count(kHelpOpt)) {
0068     std::cout << desc << std::endl;
0069     return 0;
0070   }
0071   int entryNumber = 0;
0072   if (vm.count(kEntryNumberOpt)) {
0073     entryNumber = vm[kEntryNumberOpt].as<int>();
0074   }
0075
0076   if (!vm.count(kBranchNameOpt)) {
0077     std::cerr << "no branch name given\n";
0078     return 1;
0079   }
0080
0081   if (!vm.count(kFileNameOpt)) {
0082     std::cerr << "no branch name given\n";
0083     return 1;
0084   }
0085
0086   std::string branchName(vm[kBranchNameOpt].as<std::string>());
0087   std::string fileName(vm[kFileNameOpt].as<std::string>());
0088
0089   TFile* file = TFile::Open(fileName.c_str());
0090   if (nullptr == file) {
0091     std::cerr << "failed to open '" << fileName << "'";
0092     return 1;
0093   }
0094
0095   TTree* eventTree = dynamic_cast<TTree*>(file->Get("Events"));
0096
0097   if (nullptr == eventTree) {
0098     std::cerr << "The file '" << fileName << "' does not contain an 'Events' TTree";
0099     return 1;
0100   }
0101
0102   TBranch* branch = eventTree->GetBranch(branchName.c_str());
0103
0104   if (nullptr == branch) {
0105     std::cerr << "The Events TTree does not contain the branch " << branchName;
0106     return 1;
0107   }
0108
0109   FWLiteEnabler::enable();
0110
0111   TClass* cls = TClass::GetClass(branch->GetClassName());
0112   if (nullptr == cls) {
0113     std::cerr << "class '" << branch->GetClassName() << "' is unknown by ROOT\n";
0114     return 1;
0115   }
0116
0117   void* objInstance = cls->New();
0118   if (nullptr == objInstance) {
0119     std::cerr << "unable to create a default instance of the class " << branch->GetClassName();
0120     return 1;
0121   }
0122
0123   //associate this with the branch
0124   void* pObjInstance = &objInstance;
0125
0126   branch->SetAddress(pObjInstance);
0127
0128   branch->GetEntry(entryNumber);
0129
0130   TBufferFile bf(TBuffer::kWrite);
0131
0132   gDebug = 3;
0133   cls->WriteBuffer(bf, objInstance);
0134
0135   gDebug = 0;
0136   std::cout << "Total amount stored: " << bf.Length() << " bytes" << std::endl;
0137   std::cout << "\nNOTE: add 4 bytes for each 'has written' value because of a bug in ROOT's printout of the accounting"
0138             << "\n  Each class (inheriting or as member data) has metadata an overhead of 10 bytes" << std::endl;
0139   return 0;
0140 } catch (cms::Exception const& e) {
0141   std::cerr << e.explainSelf() << std::endl;
0142   return 1;
0143 } catch (std::exception const& e) {
0144   std::cerr << e.what() << std::endl;
0145   return 1;
0146 }