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File indexing completed on 2021-02-14 13:28:25

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 "TBufferFile.h"
0018 
0019 // user include files
0020 #include "FWCore/FWLite/interface/FWLiteEnabler.h"
0021 #include "FWCore/Utilities/interface/Exception.h"
0022 
0023 //
0024 // constants, enums and typedefs
0025 //
0026 static char const* const kClassNameOpt = "className";
0027 static char const* const kHelpOpt = "help";
0028 static char const* const kHelpCommandOpt = "help,h";
0029 
0030 int main(int argc, char* argv[]) try {
0031   std::string descString(argv[0]);
0032   descString += " [options] [--";
0033   descString += kClassNameOpt;
0034   descString +=
0035       "] class_name"
0036       "\n The program dumps information about how much storage space is needed to store the class"
0037       "\nAllowed options";
0038   boost::program_options::options_description desc(descString);
0039   desc.add_options()(kHelpCommandOpt, "show this help message")(kClassNameOpt, "name of class");
0040 
0041   boost::program_options::positional_options_description p;
0042   p.add(kClassNameOpt, 1);
0043 
0044   boost::program_options::variables_map vm;
0045   try {
0046     store(boost::program_options::command_line_parser(argc, argv).options(desc).positional(p).run(), vm);
0047     notify(vm);
0048   } catch (boost::program_options::error const& iException) {
0049     std::cerr << "failed to parse command line \n" << iException.what() << "\n";
0050     return 1;
0051   }
0052 
0053   if (vm.count(kHelpOpt)) {
0054     std::cout << desc << std::endl;
0055     return 0;
0056   }
0057 
0058   if (!vm.count(kClassNameOpt)) {
0059     std::cerr << "no class name given\n";
0060     return 1;
0061   }
0062 
0063   std::string className(vm[kClassNameOpt].as<std::string>());
0064 
0065   FWLiteEnabler::enable();
0066 
0067   TClass* cls = TClass::GetClass(className.c_str());
0068   if (nullptr == cls) {
0069     std::cerr << "class '" << className << "' is unknown by ROOT\n";
0070     return 1;
0071   }
0072 
0073   void* objInstance = cls->New();
0074   if (nullptr == objInstance) {
0075     std::cerr << "unable to create a default instance of the class " << className;
0076     return 1;
0077   }
0078 
0079   TBufferFile bf(TBuffer::kWrite);
0080 
0081   gDebug = 3;
0082   cls->WriteBuffer(bf, objInstance);
0083 
0084   gDebug = 0;
0085   std::cout << "Total amount stored: " << bf.Length() << " bytes" << std::endl;
0086   std::cout << "\nNOTE: add 4 bytes for each 'has written' value because of a bug in ROOT's printout of the accounting"
0087             << "\n  Each class (inheriting or as member data) has metadata an overhead of 10 bytes" << std::endl;
0088   return 0;
0089 } catch (cms::Exception const& e) {
0090   std::cerr << e.explainSelf() << std::endl;
0091   return 1;
0092 } catch (std::exception const& e) {
0093   std::cerr << e.what() << std::endl;
0094   return 1;
0095 }