An artificial field that transforms an RNTuple column that contains the offset of collections into collection sizes.

It is used to provide the "number of" RDF columns for collections, e.g. R_rdf_sizeof_jets for a collection named jets.

This field owns the collection offset field but instead of exposing the collection offsets it exposes the collection sizes (offset(N+1) - offset(N)). For the time being, we offer this functionality only in RDataFrame. TODO(jblomer): consider providing a general set of useful virtual fields as part of RNTuple.

Definition at line 59 of file RNTupleDS.cxx.

Public Member Functions
	RRDFCardinalityField ()

	RRDFCardinalityField (RRDFCardinalityField &&other)=default

	~RRDFCardinalityField ()=default

ROOT::Experimental::Detail::RFieldValue	CaptureValue (void *where) final
	Creates a value from a memory location with an already constructed object.

void	GenerateColumnsImpl () final
	Creates the backing columns corresponsing to the field type for writing.

void	GenerateColumnsImpl (const RNTupleDescriptor &) final
	Creates the backing columns corresponsing to the field type for reading.

ROOT::Experimental::Detail::RFieldValue	GenerateValue (void *where) final
	Generates a tree value in a given location of size at least GetValueSize().

size_t	GetValueSize () const final
	The number of bytes taken by a value of the appropriate type.

RRDFCardinalityField &	operator= (RRDFCardinalityField &&other)=default

void	ReadGlobalImpl (ROOT::Experimental::NTupleSize_t globalIndex, ROOT::Experimental::Detail::RFieldValue *value) final
	Get the number of elements of the collection identified by globalIndex.

void	ReadInClusterImpl (const ROOT::Experimental::RClusterIndex &clusterIndex, ROOT::Experimental::Detail::RFieldValue *value) final
	Get the number of elements of the collection identified by clusterIndex.

Public Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
	RFieldBase (const RFieldBase &)=delete

	RFieldBase (RFieldBase &&)=default

	RFieldBase (std::string_view name, std::string_view type, ENTupleStructure structure, bool isSimple, std::size_t nRepetitions=0)
	The constructor creates the underlying column objects and connects them to either a sink or a source.

virtual	~RFieldBase ()

virtual void	AcceptVisitor (RFieldVisitor &visitor) const

std::size_t	Append (const RFieldValue &value)
	Write the given value into columns.

void	Attach (std::unique_ptr< Detail::RFieldBase > child)
	Add a new subfield to the list of nested fields.

RSchemaIterator	begin ()

std::unique_ptr< RFieldBase >	Clone (std::string_view newName) const
	Copies the field and its sub fields using a possibly new name and a new, unconnected set of columns.

virtual void	CommitCluster ()
	Perform housekeeping tasks for global to cluster-local index translation.

void	ConnectPageSink (RPageSink &pageSink)
	Fields and their columns live in the void until connected to a physical page storage.

void	ConnectPageSource (RPageSource &pageSource)

virtual void	DestroyValue (const RFieldValue &value, bool dtorOnly=false)
	Releases the resources acquired during GenerateValue (memory and constructor) This implementation works for simple types but needs to be overwritten for complex ones.

RSchemaIterator	end ()

void	Flush () const
	Ensure that all received items are written from page buffers to the storage.

RFieldValue	GenerateValue ()
	Generates an object of the field type and allocates new initialized memory according to the type.

virtual size_t	GetAlignment () const
	For many types, the alignment requirement is equal to the size; otherwise override.

std::string	GetDescription () const
	Get the field's description.

virtual std::uint32_t	GetFieldVersion () const
	Indicates an evolution of the mapping scheme from C++ type to columns.

std::string	GetName () const

NTupleSize_t	GetNElements () const

std::size_t	GetNRepetitions () const

DescriptorId_t	GetOnDiskId () const

RFieldBase *	GetParent () const

ENTupleStructure	GetStructure () const

std::vector< RFieldBase * >	GetSubFields () const

int	GetTraits () const

std::string	GetType () const

virtual std::uint32_t	GetTypeVersion () const
	Indicates an evolution of the C++ type itself.

bool	HasReadCallbacks () const

bool	IsSimple () const

RFieldBase &	operator= (const RFieldBase &)=delete

RFieldBase &	operator= (RFieldBase &&)=default

void	Read (const RClusterIndex &clusterIndex, RFieldValue *value)

void	Read (NTupleSize_t globalIndex, RFieldValue *value)
	Populate a single value with data from the tree, which needs to be of the fitting type.

void	SetDescription (std::string_view description)

void	SetOnDiskId (DescriptorId_t id)

virtual std::vector< RFieldValue >	SplitValue (const RFieldValue &value) const
	Creates the list of direct child values given a value for this field.

Static Public Member Functions
static std::string	TypeName ()

Static Public Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
static RResult< std::unique_ptr< RFieldBase > >	Create (const std::string &fieldName, const std::string &typeName)
	Factory method to resurrect a field from the stored on-disk type information.

static RResult< void >	EnsureValidFieldName (std::string_view fieldName)
	Check whether a given string is a valid field name.

Protected Member Functions
std::unique_ptr< ROOT::Experimental::Detail::RFieldBase >	CloneImpl (std::string_view) const final
	Called by Clone(), which additionally copies the on-disk ID.

Protected Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
size_t	AddReadCallback (ReadCallback_t func)
	Set a user-defined function to be called after reading a value, giving a chance to inspect and/or modify the value object.

virtual std::size_t	AppendImpl (const RFieldValue &value)
	Operations on values of complex types, e.g.

ROOT::Experimental::EColumnType	EnsureColumnType (const std::vector< EColumnType > &requestedTypes, unsigned int columnIndex, const RNTupleDescriptor &desc)
	Throws an exception if the column given by fOnDiskId and the columnIndex in the provided descriptor is not of one of the requested types.

void	RemoveReadCallback (size_t idx)

Additional Inherited Members
Static Public Attributes inherited from ROOT::Experimental::Detail::RFieldBase
static constexpr int	kTraitMappable = 0x04
	A field of a fundamental type that can be directly mapped via `RField<T>::Map()`, i.e.

static constexpr int	kTraitTriviallyConstructible = 0x01
	No constructor needs to be called, i.e.

static constexpr int	kTraitTriviallyDestructible = 0x02
	The type is cleaned up just by freeing its memory. I.e. DestroyValue() is a no-op.

static constexpr int	kTraitTrivialType = kTraitTriviallyConstructible \| kTraitTriviallyDestructible
	Shorthand for types that are both trivially constructible and destructible.

Protected Attributes inherited from ROOT::Experimental::Detail::RFieldBase
std::vector< std::unique_ptr< RColumn > >	fColumns
	The columns are connected either to a sink or to a source (not to both); they are owned by the field.

RFieldBase *	fParent
	Sub fields point to their mother field.

RColumn *	fPrincipalColumn
	Points into fColumns.

std::vector< ReadCallback_t >	fReadCallbacks
	List of functions to be called after reading a value.

std::vector< std::unique_ptr< RFieldBase > >	fSubFields
	Collections and classes own sub fields.

int	fTraits = 0
	Properties of the type that allow for optimizations of collections of that type.

Inheritance diagram for ROOT::Experimental::Internal::RRDFCardinalityField:

[legend]

Constructor & Destructor Documentation

◆ RRDFCardinalityField() [1/2]

ROOT::Experimental::Internal::RRDFCardinalityField::RRDFCardinalityField ( )

inline

Definition at line 68 of file RNTupleDS.cxx.

◆ RRDFCardinalityField() [2/2]

ROOT::Experimental::Internal::RRDFCardinalityField::RRDFCardinalityField ( RRDFCardinalityField && other )

default

◆ ~RRDFCardinalityField()

ROOT::Experimental::Internal::RRDFCardinalityField::~RRDFCardinalityField ( )

default

Member Function Documentation

◆ CaptureValue()

ROOT::Experimental::Detail::RFieldValue ROOT::Experimental::Internal::RRDFCardinalityField::CaptureValue ( void * where )

inlinefinalvirtual

Creates a value from a memory location with an already constructed object.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 89 of file RNTupleDS.cxx.

◆ CloneImpl()

std::unique_ptr< ROOT::Experimental::Detail::RFieldBase > ROOT::Experimental::Internal::RRDFCardinalityField::CloneImpl ( std::string_view newName ) const

inlinefinalprotectedvirtual

Called by Clone(), which additionally copies the on-disk ID.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 61 of file RNTupleDS.cxx.

◆ GenerateColumnsImpl() [1/2]

void ROOT::Experimental::Internal::RRDFCardinalityField::GenerateColumnsImpl ( )

inlinefinalvirtual

Creates the backing columns corresponsing to the field type for writing.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 75 of file RNTupleDS.cxx.

◆ GenerateColumnsImpl() [2/2]

void ROOT::Experimental::Internal::RRDFCardinalityField::GenerateColumnsImpl ( const RNTupleDescriptor & desc )

inlinefinalvirtual

Creates the backing columns corresponsing to the field type for reading.

The method should to check, using the page source and fOnDiskId, if the column types match and throw if they don't.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 77 of file RNTupleDS.cxx.

◆ GenerateValue()

ROOT::Experimental::Detail::RFieldValue ROOT::Experimental::Internal::RRDFCardinalityField::GenerateValue ( void * where )

inlinefinalvirtual

Generates a tree value in a given location of size at least GetValueSize().

Assumes that where has been allocated by malloc().

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 85 of file RNTupleDS.cxx.

◆ GetValueSize()

size_t ROOT::Experimental::Internal::RRDFCardinalityField::GetValueSize ( ) const

inlinefinalvirtual

The number of bytes taken by a value of the appropriate type.

Implements ROOT::Experimental::Detail::RFieldBase.

Definition at line 93 of file RNTupleDS.cxx.

◆ operator=()

RRDFCardinalityField & ROOT::Experimental::Internal::RRDFCardinalityField::operator= ( RRDFCardinalityField && other )

default

◆ ReadGlobalImpl()

void ROOT::Experimental::Internal::RRDFCardinalityField::ReadGlobalImpl	(	ROOT::Experimental::NTupleSize_t	globalIndex,
		ROOT::Experimental::Detail::RFieldValue *	value
	)

inlinefinalvirtual

Get the number of elements of the collection identified by globalIndex.

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 97 of file RNTupleDS.cxx.

◆ ReadInClusterImpl()

void ROOT::Experimental::Internal::RRDFCardinalityField::ReadInClusterImpl	(	const ROOT::Experimental::RClusterIndex &	clusterIndex,
		ROOT::Experimental::Detail::RFieldValue *	value
	)

inlinefinalvirtual

Get the number of elements of the collection identified by clusterIndex.

Reimplemented from ROOT::Experimental::Detail::RFieldBase.

Definition at line 106 of file RNTupleDS.cxx.

◆ TypeName()

static std::string ROOT::Experimental::Internal::RRDFCardinalityField::TypeName ( )

inlinestatic

Definition at line 67 of file RNTupleDS.cxx.

tree/dataframe/src/RNTupleDS.cxx

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ RRDFCardinalityField() [1/2]

◆ RRDFCardinalityField() [2/2]

◆ ~RRDFCardinalityField()

Member Function Documentation

◆ CaptureValue()

◆ CloneImpl()

◆ GenerateColumnsImpl() [1/2]

◆ GenerateColumnsImpl() [2/2]

◆ GenerateValue()

◆ GetValueSize()

◆ operator=()

◆ ReadGlobalImpl()

◆ ReadInClusterImpl()

◆ TypeName()