CbmMCInput.cxx

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/* Copyright (C) 2018-2020 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Volker Friese [committer] */
 
#include "CbmMCInput.h"
 
#include "FairMCEventHeader.h"
#include <Logger.h>
 
#include "TFile.h"
#include "TList.h"
#include "TObjString.h"
#include "TRandom.h"
 
#include <cassert>
 
 
// -----   Default constructor   ---------------------------------------------
CbmMCInput::CbmMCInput() : CbmMCInput(nullptr, ECbmTreeAccess::kRegular) {}
// ---------------------------------------------------------------------------
 
 
// -----   Constructor   -----------------------------------------------------
CbmMCInput::CbmMCInput(TChain* chain, ECbmTreeAccess mode)
  : TObject()
  , fChain(chain)
  , fMode(mode)
  , fBranches()
  , fLastUsedEntry(-1)
  , fNofUsedEntries(0)
{
}
// ---------------------------------------------------------------------------
 
 
// -----   Destructor   ------------------------------------------------------
CbmMCInput::~CbmMCInput() {}
// ---------------------------------------------------------------------------
 
 
// -----   Get branch list   -------------------------------------------------
std::set<TString>& CbmMCInput::GetBranchList()
{
 
  // At first call, read branch list from file
  if (fBranches.empty()) ReadBranches();
 
  return fBranches;
}
// ---------------------------------------------------------------------------
 
 
// -----   Get next entry from chain   ---------------------------------------
Int_t CbmMCInput::GetNextEntry()
{
 
  assert(fChain);
 
  // Determine entry number to be retrieved
  Int_t entry = -1;
  if (fMode == ECbmTreeAccess::kRandom) { entry = gRandom->Integer(GetNofEntries()); }  //? Random entry number
  else {
    entry = fLastUsedEntry + 1;
    if (entry >= GetNofEntries()) entry = (fMode == ECbmTreeAccess::kRepeat ? 0 : -1);
  }  //? Sequential entry number
 
  // Stop run when entryId is -1. This happens when mode is kRegular and
  // the end of the chain is reached.
  if (entry < 0) return -1;
 
  // Get entry from chain
  assert(entry >= 0 && entry < GetNofEntries());  // Just to make sure...
  Int_t nBytes = fChain->GetEntry(entry);
  if (nBytes <= 0) LOG(warn) << "InputChain: " << nBytes << " Bytes read from tree!";
  fLastUsedEntry = entry;
  fNofUsedEntries++;
 
  return entry;
}
// ---------------------------------------------------------------------------
 
 
// -----   Get list of data branches from file   -----------------------------
UInt_t CbmMCInput::ReadBranches()
{
 
  fBranches.clear();
  TList* listFile = fChain->GetFile()->Get<TList>("BranchList");
  assert(listFile);
  TObjString* branchName = nullptr;
  for (Int_t entry = 0; entry < listFile->GetEntries(); entry++) {
    branchName = dynamic_cast<TObjString*>(listFile->At(entry));
    assert(branchName);
    fBranches.insert(branchName->GetString());
  }  //# Entries in branch list
 
  return fBranches.size();
}
// ---------------------------------------------------------------------------
 
 
ClassImp(CbmMCInput)