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 58 of file RNTupleDS.cxx.

Public Member Functions
	RRDFCardinalityField ()

	RRDFCardinalityField (RRDFCardinalityField &&other)=default

	~RRDFCardinalityField ()=default

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

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

size_t	GetAlignment () const final
	As a rule of thumb, the alignment is equal to the size of the type.

const RColumnRepresentations &	GetColumnRepresentations () const final
	Implementations in derived classes should return a static RColumnRepresentations object.

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, void *to) final
	Get the number of elements of the collection identified by globalIndex.

void	ReadInClusterImpl (const ROOT::Experimental::RClusterIndex &clusterIndex, void *to) 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

RSchemaIterator	begin ()

RValue	BindValue (void *where)
	Creates a value from a memory location with an already constructed object.

RConstSchemaIterator	cbegin () const

RConstSchemaIterator	cend () const

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.

void	CommitCluster ()
	Flushes data from active columns to disk and calls CommitClusterImpl.

void	ConnectPageSink (RPageSink &pageSink, NTupleSize_t firstEntry=0)
	Fields and their columns live in the void until connected to a physical page storage.

void	ConnectPageSource (RPageSource &pageSource)

RSchemaIterator	end ()

RBulk	GenerateBulk ()
	The returned bulk is initially empty; RBulk::ReadBulk will construct the array of values.

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

const ColumnRepresentation_t &	GetColumnRepresentative () const
	Returns the fColumnRepresentative pointee or, if unset, the field's default representative.

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

std::uint32_t	GetOnDiskTypeVersion () const
	Return the C++ type version stored in the field descriptor; only valid after a call to `ConnectPageSource()`

RFieldBase *	GetParent () const

std::string	GetQualifiedFieldName () const
	Returns the field name and parent field names separated by dots ("grandparent.parent.child")

EState	GetState () const

ENTupleStructure	GetStructure () const

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

int	GetTraits () const

std::string	GetType () const

std::string	GetTypeAlias () const

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

bool	HasDefaultColumnRepresentative () const
	Whether or not an explicit column representative was set.

bool	HasReadCallbacks () const

bool	IsSimple () const

RFieldBase &	operator= (const RFieldBase &)=delete

RFieldBase &	operator= (RFieldBase &&)=default

void	SetColumnRepresentative (const ColumnRepresentation_t &representative)
	Fixes a column representative.

void	SetDescription (std::string_view description)

void	SetOnDiskId (DescriptorId_t id)

virtual std::vector< RValue >	SplitValue (const RValue &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.

void	GenerateValue (void *where) const final
	Constructs value in a given location of size at least GetValueSize(). Called by the base class' GenerateValue().

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.

std::size_t	Append (const void *from)
	Write the given value into columns.

virtual std::size_t	AppendImpl (const void *from)
	Operations on values of complex types, e.g.

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

void	AutoAdjustColumnTypes (const RNTupleWriteOptions &options)
	When connecting a field to a page sink, the field's default column representation is subject to adjustment according to the write options.

virtual void	CommitClusterImpl ()

virtual void	DestroyValue (void *objPtr, bool dtorOnly=false) const
	Releases the resources acquired during GenerateValue (memory and constructor) This implementation works for types with a trivial destructor and should be overwritten otherwise.

const ColumnRepresentation_t &	EnsureCompatibleColumnTypes (const RNTupleDescriptor &desc) const
	Returns the on-disk column types found in the provided descriptor for fOnDiskId.

virtual void	OnConnectPageSource ()
	Called by `ConnectPageSource()` only once connected; derived classes may override this as appropriate.

void	Read (const RClusterIndex &clusterIndex, void *to)

void	Read (NTupleSize_t globalIndex, void *to)
	Populate a single value with data from the field.

std::size_t	ReadBulk (const RBulkSpec &bulkSpec)
	Returns the number of newly available values, that is the number of bools in bulkSpec.fMaskAvail that flipped from false to true.

virtual std::size_t	ReadBulkImpl (const RBulkSpec &bulkSpec)
	General implementation of bulk read.

void	RemoveReadCallback (size_t idx)

Additional Inherited Members
Public Types inherited from ROOT::Experimental::Detail::RFieldBase
using	ColumnRepresentation_t = std::vector< EColumnType >

enum class	EState { kUnconnected , kConnectedToSink , kConnectedToSource }
	During its lifetime, a field undergoes the following possible state transitions: More...

using	RConstSchemaIterator = RSchemaIteratorTemplate< true >

using	RSchemaIterator = RSchemaIteratorTemplate< false >

Static Public Attributes inherited from ROOT::Experimental::Detail::RFieldBase
static constexpr std::uint32_t	kInvalidTypeVersion = -1U

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.

Static Protected Member Functions inherited from ROOT::Experimental::Detail::RFieldBase
static std::size_t	CallAppendOn (RFieldBase &other, const void *from)
	Allow derived classes to call Append and Read on other (sub) fields.

static void	CallDestroyValueOn (const RFieldBase &other, void *objPtr, bool dtorOnly=false)

static void	CallGenerateValueOn (const RFieldBase &other, void *where)
	Allow derived classes to call GenerateValue(void *) and DestroyValue on other (sub) fields.

static void	CallReadOn (RFieldBase &other, const RClusterIndex &clusterIndex, void *to)

static void	CallReadOn (RFieldBase &other, NTupleSize_t globalIndex, void *to)

static RResult< std::unique_ptr< RFieldBase > >	Create (const std::string &fieldName, const std::string &canonicalType, const std::string &typeAlias)
	Factory method to resurrect a field from the stored on-disk type information.

static RColumn *	GetPrincipalColumnOf (const RFieldBase &other)
	Fields may need direct access to the principal column of their sub fields, e.g. in RRVecField::ReadBulk.

Protected Attributes inherited from ROOT::Experimental::Detail::RFieldBase
const ColumnRepresentation_t *	fColumnRepresentative = nullptr
	Points into the static vector GetColumnRepresentations().GetSerializationTypes() when SetColumnRepresentative is called.

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.

std::uint32_t	fOnDiskTypeVersion = kInvalidTypeVersion
	C++ type version cached from the descriptor after a call to `ConnectPageSource()`

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.

std::string	fTypeAlias
	A typedef or using name that was used when creating the field.

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

◆ 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 60 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 82 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 83 of file RNTupleDS.cxx.

◆ GenerateValue()

void ROOT::Experimental::Internal::RRDFCardinalityField::GenerateValue ( void * where ) const

inlinefinalprotectedvirtual

Constructs value in a given location of size at least GetValueSize(). Called by the base class' GenerateValue().

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

Definition at line 64 of file RNTupleDS.cxx.

◆ GetAlignment()

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

inlinefinalvirtual

As a rule of thumb, the alignment is equal to the size of the type.

There are, however, various exceptions to this rule depending on OS and CPU architecture. So enforce the alignment to be explicitly spelled out.

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

Definition at line 91 of file RNTupleDS.cxx.

◆ GetColumnRepresentations()

const RColumnRepresentations & ROOT::Experimental::Internal::RRDFCardinalityField::GetColumnRepresentations ( ) const

inlinefinalvirtual

Implementations in derived classes should return a static RColumnRepresentations object.

The default implementation does not attach any columns to the field.

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

Definition at line 74 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 90 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,
		void *	to
	)

inlinefinalvirtual

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

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

Definition at line 94 of file RNTupleDS.cxx.

◆ ReadInClusterImpl()

void ROOT::Experimental::Internal::RRDFCardinalityField::ReadInClusterImpl	(	const ROOT::Experimental::RClusterIndex &	clusterIndex,
		void *	to
	)

inlinefinalvirtual

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

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

Definition at line 103 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

◆ CloneImpl()

◆ GenerateColumnsImpl() [1/2]

◆ GenerateColumnsImpl() [2/2]

◆ GenerateValue()

◆ GetAlignment()

◆ GetColumnRepresentations()

◆ GetValueSize()

◆ operator=()

◆ ReadGlobalImpl()

◆ ReadInClusterImpl()

◆ TypeName()