include/HepMC3/ReaderFactory.h

0001 // -*- C++ -*-
0002 //
0003 // This file is part of HepMC
0004 // Copyright (C) 2014-2023 The HepMC collaboration (see AUTHORS for details)
0005 //
0006 /**
0007  *  @file ReaderFactory.h
0008  *  @brief Declaration of \b deduce_reader and related functions
0009  *
0010  */
0011 #ifndef HEPMC3_READERFACTORY_H
0012 #define HEPMC3_READERFACTORY_H
0013
0014
0015 #include "HepMC3/ReaderFactory_fwd.h"
0016 #include "HepMC3/CompressedIO.h"
0017
0018 namespace HepMC3 {
0019
0020 /**
0021  * @brief This function deduces the type of input file based on the name/URL
0022  * and its content, and will return an appropriate Reader object.
0023  *
0024  */
0025
0026 inline std::shared_ptr<Reader> deduce_reader(const std::string &filename)
0027 {
0028     InputInfo input(filename);
0029     if (input.m_init && !input.m_error && input.m_reader) return input.m_reader;
0030     if (input.m_root || input.m_remote) {
0031         HEPMC3_DEBUG(10, "deduce_reader: Attempt ReaderRootTree for " << filename);
0032         return   std::make_shared<ReaderPlugin>(filename, libHepMC3rootIO, std::string("newReaderRootTreefile"));
0033     }
0034     if (input.m_protobuf) {
0035         HEPMC3_DEBUG(10, "deduce_reader: Attempt ProtobufIO for " << filename);
0036         return std::make_shared<ReaderPlugin>(filename, libHepMC3protobufIO, std::string("newReaderprotobuffile"));
0037     }
0038 #if HEPMC3_USE_COMPRESSION
0039     HEPMC3_DEBUG(10, "Attempt ReaderGZ for " << filename);
0040     char buf[6];
0041     snprintf(buf, 6, "%s", input.m_head.at(0).c_str());
0042     Compression det = detect_compression_type(buf, buf + 6);
0043     if ( det != Compression::plaintext ) {
0044         HEPMC3_DEBUG(10, "Detected supported compression: " << det);
0045         return deduce_reader(std::shared_ptr< std::istream >(new ifstream(filename.c_str())));
0046     }
0047 #endif
0048     std::string f = filename;
0049     return input.native_reader(f);
0050 }
0051 }
0052 #endif