ROOT::Experimental::RNTupleView< T > Class Template Reference

template<typename T>
class ROOT::Experimental::RNTupleView< T >

An RNTupleView provides read-only access to a single field of the ntuple.

The view owns a field and its underlying columns in order to fill an ntuple value object with data. Data can be accessed by index. For top-level fields, the index refers to the entry number. Fields that are part of nested collections have global index numbers that are derived from their parent indexes.

Fields of simple types with a Map() method will use that and thus expose zero-copy access.

Definition at line 141 of file RNTupleView.hxx.

Public Types
using	FieldTypeT = T

Public Member Functions
	RNTupleView (const RNTupleView &other)=delete
	RNTupleView (DescriptorId_t fieldId, Detail::RPageSource *pageSource)
	RNTupleView (RNTupleView &&other)=default
	~RNTupleView ()=default
RNTupleGlobalRange	GetFieldRange () const
template<typename C = T, std::enable_if_t< Internal::isMappable< FieldT >, C * > = nullptr>
const C *	MapV (const RClusterIndex &clusterIndex, NTupleSize_t &nItems)
template<typename C = T, std::enable_if_t< Internal::isMappable< FieldT >, C * > = nullptr>
const C *	MapV (NTupleSize_t globalIndex, NTupleSize_t &nItems)
const T &	operator() (const RClusterIndex &clusterIndex)
const T &	operator() (NTupleSize_t globalIndex)
RNTupleView &	operator= (const RNTupleView &other)=delete
RNTupleView &	operator= (RNTupleView &&other)=default

Private Types
using	FieldT = RField< T >

Private Attributes
FieldT	fField
	fFieldId has fParent always set to null; views access nested fields without looking at the parent
Detail::RFieldBase::RValue	fValue
	Used as a Read() destination for fields that are not mappable.

Friends
class	RNTupleViewCollection

#include <ROOT/RNTupleView.hxx>

Member Typedef Documentation

FieldT

template<typename T >

using ROOT::Experimental::RNTupleView< T >::FieldT = RField<T>

private

Definition at line 144 of file RNTupleView.hxx.

FieldTypeT

template<typename T >

using ROOT::Experimental::RNTupleView< T >::FieldTypeT = T

Definition at line 153 of file RNTupleView.hxx.

Constructor & Destructor Documentation

RNTupleView() [1/3]

template<typename T >

ROOT::Experimental::RNTupleView< T >::RNTupleView ( DescriptorId_t  fieldId, Detail::RPageSource *  pageSource  )

inline

Definition at line 155 of file RNTupleView.hxx.

RNTupleView() [2/3]

template<typename T >

ROOT::Experimental::RNTupleView< T >::RNTupleView ( const RNTupleView< T > &  other )

delete

RNTupleView() [3/3]

template<typename T >

ROOT::Experimental::RNTupleView< T >::RNTupleView ( RNTupleView< T > &&  other )

default

~RNTupleView()

template<typename T >

ROOT::Experimental::RNTupleView< T >::~RNTupleView ( )

default

Member Function Documentation

GetFieldRange()

template<typename T >

RNTupleGlobalRange ROOT::Experimental::RNTupleView< T >::GetFieldRange ( ) const

inline

Definition at line 177 of file RNTupleView.hxx.

MapV() [1/2]

template<typename T >

template<typename C = T, std::enable_if_t< Internal::isMappable< FieldT >, C * > = nullptr>

const C * ROOT::Experimental::RNTupleView< T >::MapV ( const RClusterIndex &  clusterIndex, NTupleSize_t &  nItems  )

inline

Definition at line 208 of file RNTupleView.hxx.

MapV() [2/2]

template<typename T >

template<typename C = T, std::enable_if_t< Internal::isMappable< FieldT >, C * > = nullptr>

const C * ROOT::Experimental::RNTupleView< T >::MapV ( NTupleSize_t  globalIndex, NTupleSize_t &  nItems  )

inline

Definition at line 201 of file RNTupleView.hxx.

operator()() [1/2]

template<typename T >

const T & ROOT::Experimental::RNTupleView< T >::operator() ( const RClusterIndex &  clusterIndex )

inline

Definition at line 189 of file RNTupleView.hxx.

operator()() [2/2]

template<typename T >

const T & ROOT::Experimental::RNTupleView< T >::operator() ( NTupleSize_t  globalIndex )

inline

Definition at line 179 of file RNTupleView.hxx.

operator=() [1/2]

template<typename T >

RNTupleView & ROOT::Experimental::RNTupleView< T >::operator= ( const RNTupleView< T > &  other )

delete

operator=() [2/2]

template<typename T >

RNTupleView & ROOT::Experimental::RNTupleView< T >::operator= ( RNTupleView< T > &&  other )

default

Friends And Related Symbol Documentation

RNTupleViewCollection

template<typename T >

friend class RNTupleViewCollection

friend

Definition at line 142 of file RNTupleView.hxx.

Member Data Documentation

fField

template<typename T >

FieldT ROOT::Experimental::RNTupleView< T >::fField

private

fFieldId has fParent always set to null; views access nested fields without looking at the parent

Definition at line 148 of file RNTupleView.hxx.

fValue

template<typename T >

Detail::RFieldBase::RValue ROOT::Experimental::RNTupleView< T >::fValue

private

Used as a Read() destination for fields that are not mappable.

Definition at line 150 of file RNTupleView.hxx.