Encapsulates a branch within a ROOT TTree, managing the data and interaction with the TTree. More...

#include </builds/gaudi/Gaudi/GaudiUtils/include/Gaudi/details/BranchWrapper.h>

Collaboration diagram for Gaudi::details::BranchWrapper:

[legend]

Public Member Functions
	BranchWrapper (const gsl::not_null< TTree * > tree, const std::string &className, const std::string &branchName, const std::string &location, const std::string &algName, unsigned int bufferSize=32000, unsigned int splitLevel=99)

void	setDataPtr (void const *dataPtr)

void	setBranchData (const gsl::not_null< DataObject * > pObj)

const std::string &	getLocation () const

const std::string &	getClassName () const

void	setBufferSize (unsigned int size)

unsigned int	computeOptimalBufferSize (unsigned int minBufferSize, unsigned int maxBufferSize, unsigned int approxEventsPerBasket, unsigned int splitLevel)
	compute optimal buffer size to fit given number of element per basket, respecting given min and max

void	padEntries ()
	pad the number of item in the branch to the one of the Tree in which it leaves by adding empty entries

Private Attributes
void const *	m_dataBuffer = nullptr

TBranch *	m_branch = nullptr

std::string	m_className

std::string	m_location

void(*	setBranchAddress )(gsl::not_null< TBranch * >, const void **)

Detailed Description

Encapsulates a branch within a ROOT TTree, managing the data and interaction with the TTree.

Definition at line 25 of file BranchWrapper.h.

Constructor & Destructor Documentation

◆ BranchWrapper()

Gaudi::details::BranchWrapper::BranchWrapper	(	const gsl::not_null< TTree * >	tree,
		const std::string &	className,
		const std::string &	branchName,
		const std::string &	location,
		const std::string &	algName,
		unsigned int	bufferSize = 32000,
		unsigned int	splitLevel = 99 )

Definition at line 37 of file BranchWrapper.cpp.

      : m_className( className ), m_location( location ) {
    auto leafListTag = getLeafListForType( m_className );
    if ( leafListTag ) {
      // Create a branch for fundamental types using the leaflist
      m_branch         = tree->Branch( branchName.c_str(), &m_dataBuffer,
                                       ( std::format( "{}/{}", m_className, leafListTag.value() ) ).c_str(), bufferSize );
      setBranchAddress = []( gsl::not_null<TBranch*> br, const void** wrappedDataPtr ) {
        br->SetAddress( const_cast<void*>( *wrappedDataPtr ) );
      };
 
    } else if ( TClass::GetClass( m_className.c_str() ) ) {
      // Create a branch for object types using the classname string
      m_branch         = tree->Branch( branchName.c_str(), m_className.c_str(), &m_dataBuffer, bufferSize, splitLevel );
      setBranchAddress = []( gsl::not_null<TBranch*> br, const void** wrappedDataPtr ) {
        br->SetAddress( wrappedDataPtr );
      };
 
    } else {
      throw GaudiException( std::format( "Cannot create branch {} for unknown class: {}. Provide a dictionary please.",
                                         branchName, m_className ),
                            algName, StatusCode::FAILURE );
    }
 
    if ( !m_branch ) {
      throw GaudiException( std::format( "Failed to create branch {} for type {}.", branchName, m_className ), algName,
                            StatusCode::FAILURE );
    }
  }

Member Function Documentation

◆ computeOptimalBufferSize()

unsigned int Gaudi::details::BranchWrapper::computeOptimalBufferSize	(	unsigned int	minBufferSize,
		unsigned int	maxBufferSize,
		unsigned int	approxEventsPerBasket,
		unsigned int	splitLevel )

compute optimal buffer size to fit given number of element per basket, respecting given min and max

Definition at line 84 of file BranchWrapper.cpp.

                                                                                                                      {
    // simply try to write one item in a dummey branch of a dummy tree im memory and measure size
    auto dummy_file  = std::make_unique<TMemFile>( "dummy.root", "CREATE" );
    auto dummy_tree  = std::make_unique<TTree>( "DummyTree", "DummyTree", splitLevel, dummy_file->GetDirectory( "/" ) );
    auto leafListTag = getLeafListForType( m_className );
    TBranch* dummy_branch{ nullptr };
    if ( leafListTag ) {
      // Create a branch for fundamental types using the leaflist
      dummy_branch =
          dummy_tree->Branch( "DummyBranch", &m_dataBuffer,
                              ( fmt::format( "{}/{}", m_className, leafListTag.value() ) ).c_str(), minBufferSize );
    } else if ( TClass::GetClass( m_className.c_str() ) ) {
      // Create a branch for object types using the classname string
      dummy_branch = dummy_tree->Branch( "DummyBranch", m_className.c_str(), &m_dataBuffer, minBufferSize, splitLevel );
    } // no else as unknown className would have raised an exception at constructor level
    int nWritten = dummy_branch->Fill();
    if ( nWritten >= 0 ) {
      unsigned int newBasketSize = nWritten * approxEventsPerBasket;
      // Ensure that newBasketSize doesn't wrap around
      if ( std::numeric_limits<Int_t>::max() / approxEventsPerBasket < (unsigned int)nWritten ) {
        newBasketSize = std::numeric_limits<Int_t>::max();
      }
      return std::min( maxBufferSize, std::max( minBufferSize, newBasketSize ) );
    }
    return minBufferSize;
  }

◆ getClassName()

const std::string & Gaudi::details::BranchWrapper::getClassName ( ) const

inline

Definition at line 44 of file BranchWrapper.h.

44{ return m_className; }

◆ getLocation()

const std::string & Gaudi::details::BranchWrapper::getLocation ( ) const

inline

Definition at line 43 of file BranchWrapper.h.

43{ return m_location; }

◆ padEntries()

void Gaudi::details::BranchWrapper::padEntries ( )

pad the number of item in the branch to the one of the Tree in which it leaves by adding empty entries

Definition at line 112 of file BranchWrapper.cpp.

                                 {
    if ( !m_branch ) return;
    auto nEvents  = m_branch->GetTree()->GetEntries();
    auto nEntries = m_branch->GetEntries();
    if ( nEntries < nEvents ) {
      m_branch->SetAddress( nullptr );
      for ( auto i = nEntries; i < nEvents; i++ ) { m_branch->Fill(); }
    }
  }

◆ setBranchData()

void Gaudi::details::BranchWrapper::setBranchData ( const gsl::not_null< DataObject * > pObj )

Definition at line 78 of file BranchWrapper.cpp.

                                                                         {
    auto baseWrapper = dynamic_cast<AnyDataWrapperBase*>( pObj.get() );
    m_dataBuffer     = baseWrapper ? baseWrapper->payload() : pObj.get();
    setBranchAddress( m_branch, &m_dataBuffer );
  }

◆ setBufferSize()

void Gaudi::details::BranchWrapper::setBufferSize ( unsigned int size )

inline

Definition at line 45 of file BranchWrapper.h.

45{ m_branch->SetBasketSize( size ); }

◆ setDataPtr()

void Gaudi::details::BranchWrapper::setDataPtr ( void const * dataPtr )

Definition at line 71 of file BranchWrapper.cpp.

                                                      {
    m_dataBuffer = dataPtr;
    setBranchAddress( m_branch, &m_dataBuffer );
  }

Member Data Documentation

◆ m_branch

TBranch* Gaudi::details::BranchWrapper::m_branch = nullptr

private

Definition at line 29 of file BranchWrapper.h.

◆ m_className

std::string Gaudi::details::BranchWrapper::m_className

private

Definition at line 30 of file BranchWrapper.h.

◆ m_dataBuffer

void const* Gaudi::details::BranchWrapper::m_dataBuffer = nullptr

private

Definition at line 28 of file BranchWrapper.h.

◆ m_location

std::string Gaudi::details::BranchWrapper::m_location

private

Definition at line 31 of file BranchWrapper.h.

◆ setBranchAddress

void(* Gaudi::details::BranchWrapper::setBranchAddress) (gsl::not_null< TBranch * >, const void **)

private

Definition at line 32 of file BranchWrapper.h.

The documentation for this struct was generated from the following files:

GaudiUtils/include/Gaudi/details/BranchWrapper.h
GaudiUtils/src/Lib/BranchWrapper.cpp

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ BranchWrapper()

Member Function Documentation

◆ computeOptimalBufferSize()

◆ getClassName()

◆ getLocation()

◆ padEntries()

◆ setBranchData()

◆ setBufferSize()

◆ setDataPtr()

Member Data Documentation

◆ m_branch

◆ m_className

◆ m_dataBuffer

◆ m_location

◆ setBranchAddress