Interface for iterating over entries of RNTuples and vertically concatenated RNTuples (chains).

Example usage (see ntpl012_processor.C for a full example):

#include <ROOT/RNTupleProcessor.hxx>
using ROOT::Experimental::RNTupleProcessor;
using ROOT::Experimental::RNTupleOpenSpec;
 
std::vector<RNTupleOpenSpec> ntuples = {{"ntuple1", "ntuple1.root"}, {"ntuple2", "ntuple2.root"}};
auto processor = RNTupleProcessor::CreateChain(ntuples);
 
for (const auto &entry : processor) {
   std::cout << "pt = " << *entry.GetPtr<float>("pt") << std::endl;
}

An RNTupleProcessor is created by providing one or more RNTupleOpenSpecs, each of which contains the name and storage location of a single RNTuple. The RNTuples are processed in the order in which they were provided.

The RNTupleProcessor constructor also (optionally) accepts an RNTupleModel, which determines which fields should be read. If no model is provided, a default model based on the descriptor of the first specified RNTuple will be used. If a field that was present in the first RNTuple is not found in a subsequent one, an error will be thrown.

The RNTupleProcessor provides an iterator which gives access to the REntry containing the field data for the current entry. Additional bookkeeping information can be obtained through the RNTupleProcessor itself.

Definition at line 67 of file RNTupleProcessor.hxx.

Classes
class	RFieldContext
	Manager for a field as part of the RNTupleProcessor. More...

class	RIterator
	Iterator over the entries of an RNTuple, or vertical concatenation thereof. More...

Public Member Functions
	RNTupleProcessor (const RNTupleProcessor &)=delete

	RNTupleProcessor (RNTupleProcessor &&)=delete

virtual	~RNTupleProcessor ()=default

RIterator	begin ()

RIterator	end ()

std::size_t	GetCurrentNTupleNumber () const
	Get the index to the RNTuple currently being processed, according to the sources specified upon creation.

const REntry &	GetEntry () const
	Returns a reference to the entry used by the processor.

NTupleSize_t	GetLocalEntryNumber () const
	Get the entry number local to the RNTuple that is currently being processed.

NTupleSize_t	GetNEntriesProcessed () const
	Get the total number of entries processed so far.

RNTupleProcessor &	operator= (const RNTupleProcessor &)=delete

RNTupleProcessor &	operator= (RNTupleProcessor &&)=delete

Static Public Member Functions
static std::unique_ptr< RNTupleProcessor >	Create (const RNTupleOpenSpec &ntuple)

static std::unique_ptr< RNTupleProcessor >	Create (const RNTupleOpenSpec &ntuple, RNTupleModel &model)

static std::unique_ptr< RNTupleProcessor >	CreateChain (const std::vector< RNTupleOpenSpec > &ntuples, std::unique_ptr< RNTupleModel > model=nullptr)
	Create a new RNTuple processor chain for vertical concatenation of RNTuples.

static std::unique_ptr< RNTupleProcessor >	CreateJoin (const std::vector< RNTupleOpenSpec > &ntuples, const std::vector< std::string > &joinFields, std::vector< std::unique_ptr< RNTupleModel > > models={})
	Create a new RNTuple processor for horizontallly concatenated RNTuples.

Protected Member Functions
	RNTupleProcessor (const std::vector< RNTupleOpenSpec > &ntuples)

virtual NTupleSize_t	Advance ()=0
	Advance the processor to the next available entry.

void	ConnectField (RFieldContext &fieldContext, Internal::RPageSource &pageSource, REntry &entry)
	Creates and connects a concrete field to the current page source, based on its proto field.

virtual void	LoadEntry ()=0
	Fill the entry with values belonging to the current entry number.

void	SetLocalEntryNumber (NTupleSize_t entryNumber)
	Set the local (i.e.

Protected Attributes
std::size_t	fCurrentNTupleNumber

std::unique_ptr< REntry >	fEntry

std::unordered_map< std::string, RFieldContext >	fFieldContexts

NTupleSize_t	fLocalEntryNumber

NTupleSize_t	fNEntriesProcessed

std::vector< RNTupleOpenSpec >	fNTuples

std::unique_ptr< Internal::RPageSource >	fPageSource

#include <ROOT/RNTupleProcessor.hxx>

Inheritance diagram for ROOT::Experimental::RNTupleProcessor:

[legend]

Constructor & Destructor Documentation

◆ RNTupleProcessor() [1/3]

ROOT::Experimental::RNTupleProcessor::RNTupleProcessor ( const std::vector< RNTupleOpenSpec > & ntuples )

inlineprotected

Definition at line 143 of file RNTupleProcessor.hxx.

◆ RNTupleProcessor() [2/3]

ROOT::Experimental::RNTupleProcessor::RNTupleProcessor ( const RNTupleProcessor & )

delete

◆ RNTupleProcessor() [3/3]

ROOT::Experimental::RNTupleProcessor::RNTupleProcessor ( RNTupleProcessor && )

delete

◆ ~RNTupleProcessor()

virtual ROOT::Experimental::RNTupleProcessor::~RNTupleProcessor ( )

virtualdefault

Member Function Documentation

◆ Advance()

virtual NTupleSize_t ROOT::Experimental::RNTupleProcessor::Advance ( )

protectedpure virtual

Advance the processor to the next available entry.

Returns: The number of the entry loaded after advancing, or kInvalidNTupleIndex if there was no entry to advance to.

Checks if the end of the currently connected RNTuple is reached. If this is the case, either the next RNTuple is connected or the iterator has reached the end.

Implemented in ROOT::Experimental::RNTupleSingleProcessor, ROOT::Experimental::RNTupleChainProcessor, and ROOT::Experimental::RNTupleJoinProcessor.

◆ begin()

RIterator ROOT::Experimental::RNTupleProcessor::begin ( )

inline

Definition at line 239 of file RNTupleProcessor.hxx.

◆ ConnectField()

void ROOT::Experimental::RNTupleProcessor::ConnectField	(	RFieldContext &	fieldContext,
		Internal::RPageSource &	pageSource,
		REntry &	entry
	)

protected

Creates and connects a concrete field to the current page source, based on its proto field.

Definition at line 100 of file RNTupleProcessor.cxx.

◆ Create() [1/2]

std::unique_ptr< ROOT::Experimental::RNTupleProcessor > ROOT::Experimental::RNTupleProcessor::Create ( const RNTupleOpenSpec & ntuple )

static

Definition at line 35 of file RNTupleProcessor.cxx.

◆ Create() [2/2]

std::unique_ptr< ROOT::Experimental::RNTupleProcessor > ROOT::Experimental::RNTupleProcessor::Create	(	const RNTupleOpenSpec &	ntuple,
		RNTupleModel &	model
	)

static

Definition at line 44 of file RNTupleProcessor.cxx.

◆ CreateChain()

std::unique_ptr< ROOT::Experimental::RNTupleProcessor > ROOT::Experimental::RNTupleProcessor::CreateChain	(	const std::vector< RNTupleOpenSpec > &	ntuples,
		std::unique_ptr< RNTupleModel >	model = `nullptr`
	)

static

Create a new RNTuple processor chain for vertical concatenation of RNTuples.

Parameters

[in]	ntuples	A list specifying the names and locations of the ntuples to process.
[in]	model	An RNTupleModel specifying which fields can be read by the processor. If no model is provided, one will be created based on the descriptor of the first ntuple specified.

Returns: A pointer to the newly created RNTupleProcessor.

Definition at line 50 of file RNTupleProcessor.cxx.

◆ CreateJoin()

std::unique_ptr< ROOT::Experimental::RNTupleProcessor > ROOT::Experimental::RNTupleProcessor::CreateJoin	(	const std::vector< RNTupleOpenSpec > &	ntuples,
		const std::vector< std::string > &	joinFields,
		std::vector< std::unique_ptr< RNTupleModel > >	models = `{}`
	)

static

Create a new RNTuple processor for horizontallly concatenated RNTuples.

Parameters

[in]	ntuples	A list specifying the names and locations of the ntuples to process. The first ntuple in the list will be considered the primary ntuple and drives the processor iteration loop. Subsequent ntuples are considered auxiliary, whose entries to be read are determined by the primary ntuple (which does not necessarily have to be sequential).
[in]	joinFields	The names of the fields on which to join, in case the specified ntuples are unaligned. The join is made based on the combined join field values, and therefore each field has to be present in each specified RNTuple. If an empty list is provided, it is assumed that the specified ntuple are fully aligned, and `RNTupleIndex` will not be used.
[in]	models	A list of models for the ntuples. This list must either contain a model for each ntuple in `ntuples` (following the specification order), or be empty. When the list is empty, the default model (i.e. containing all fields) will be used for each ntuple.

Returns: A pointer to the newly created RNTupleProcessor.

Definition at line 57 of file RNTupleProcessor.cxx.

◆ end()

RIterator ROOT::Experimental::RNTupleProcessor::end ( )

inline

Definition at line 240 of file RNTupleProcessor.hxx.

◆ GetCurrentNTupleNumber()

std::size_t ROOT::Experimental::RNTupleProcessor::GetCurrentNTupleNumber ( ) const

inline

Get the index to the RNTuple currently being processed, according to the sources specified upon creation.

Definition at line 163 of file RNTupleProcessor.hxx.

◆ GetEntry()

const REntry & ROOT::Experimental::RNTupleProcessor::GetEntry ( ) const

inline

Returns a reference to the entry used by the processor.

Returns: A reference to the entry used by the processor.

Definition at line 176 of file RNTupleProcessor.hxx.

◆ GetLocalEntryNumber()

NTupleSize_t ROOT::Experimental::RNTupleProcessor::GetLocalEntryNumber ( ) const

inline

Get the entry number local to the RNTuple that is currently being processed.

When only one RNTuple is present in the processor chain, the return value is equal to GetGlobalEntryNumber.

Definition at line 169 of file RNTupleProcessor.hxx.

◆ GetNEntriesProcessed()

NTupleSize_t ROOT::Experimental::RNTupleProcessor::GetNEntriesProcessed ( ) const

inline

Get the total number of entries processed so far.

When only one RNTuple is present in the processor chain, the return value is equal to GetLocalEntryNumber.

Definition at line 159 of file RNTupleProcessor.hxx.

◆ LoadEntry()

virtual void ROOT::Experimental::RNTupleProcessor::LoadEntry ( )

protectedpure virtual

Fill the entry with values belonging to the current entry number.

Implemented in ROOT::Experimental::RNTupleSingleProcessor, ROOT::Experimental::RNTupleChainProcessor, and ROOT::Experimental::RNTupleJoinProcessor.

◆ operator=() [1/2]

RNTupleProcessor & ROOT::Experimental::RNTupleProcessor::operator= ( const RNTupleProcessor & )

delete

◆ operator=() [2/2]

RNTupleProcessor & ROOT::Experimental::RNTupleProcessor::operator= ( RNTupleProcessor && )

delete

◆ SetLocalEntryNumber()

void ROOT::Experimental::RNTupleProcessor::SetLocalEntryNumber ( NTupleSize_t entryNumber )

inlineprotected

Set the local (i.e.

relative to the page source currently openend) entry number. Used by RNTupleProcessor::RIterator.

Parameters

[in] entryNumber

Definition at line 141 of file RNTupleProcessor.hxx.

Member Data Documentation

◆ fCurrentNTupleNumber

std::size_t ROOT::Experimental::RNTupleProcessor::fCurrentNTupleNumber

protected

Definition at line 115 of file RNTupleProcessor.hxx.

◆ fEntry

std::unique_ptr<REntry> ROOT::Experimental::RNTupleProcessor::fEntry

protected

Definition at line 109 of file RNTupleProcessor.hxx.

◆ fFieldContexts

std::unordered_map<std::string, RFieldContext> ROOT::Experimental::RNTupleProcessor::fFieldContexts

protected

Definition at line 112 of file RNTupleProcessor.hxx.

◆ fLocalEntryNumber

NTupleSize_t ROOT::Experimental::RNTupleProcessor::fLocalEntryNumber

protected

Definition at line 116 of file RNTupleProcessor.hxx.

◆ fNEntriesProcessed

NTupleSize_t ROOT::Experimental::RNTupleProcessor::fNEntriesProcessed

protected

Definition at line 114 of file RNTupleProcessor.hxx.

◆ fNTuples

std::vector<RNTupleOpenSpec> ROOT::Experimental::RNTupleProcessor::fNTuples

protected

Definition at line 108 of file RNTupleProcessor.hxx.

◆ fPageSource

std::unique_ptr<Internal::RPageSource> ROOT::Experimental::RNTupleProcessor::fPageSource

protected

Definition at line 110 of file RNTupleProcessor.hxx.

Libraries for ROOT::Experimental::RNTupleProcessor:

[legend]

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

tree/ntuple/v7/inc/ROOT/RNTupleProcessor.hxx
tree/ntuple/v7/src/RNTupleProcessor.cxx

Classes

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Constructor & Destructor Documentation

◆ RNTupleProcessor() [1/3]

◆ RNTupleProcessor() [2/3]

◆ RNTupleProcessor() [3/3]

◆ ~RNTupleProcessor()

Member Function Documentation

◆ Advance()

◆ begin()

◆ ConnectField()

◆ Create() [1/2]

◆ Create() [2/2]

◆ CreateChain()

◆ CreateJoin()

◆ end()

◆ GetCurrentNTupleNumber()

◆ GetEntry()

◆ GetLocalEntryNumber()

◆ GetNEntriesProcessed()

◆ LoadEntry()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ SetLocalEntryNumber()

Member Data Documentation

◆ fCurrentNTupleNumber

◆ fEntry

◆ fFieldContexts

◆ fLocalEntryNumber

◆ fNEntriesProcessed

◆ fNTuples

◆ fPageSource