template<typename T>
class TTreeReaderArray< T >

An interface for reading collections stored in ROOT columnar datasets.

The TTreeReaderArray is a type-safe tool to be used in association with a TTreeReader to access the collections stored in TTree, TNtuple and TChain datasets. In order to access values which are not collections, the TTreeReaderValue class can be used.

See the documentation of TTreeReader for more details and examples.

Definition at line 104 of file TTreeReaderArray.h.

Classes
class	Iterator_t
	Random access iterator to the elements of a TTreeReaderArray. More...

Public Types
using	const_iterator = Iterator_t<const TTreeReaderArray<T>>

using	iterator = Iterator_t<TTreeReaderArray<T>>

Public Types inherited from ROOT::Internal::TTreeReaderValueBase
typedef bool(ROOT::Detail::TBranchProxy::*	BranchProxyRead_t) ()

enum	EReadStatus { kReadSuccess = 0 , kReadNothingYet , kReadError }

enum	ESetupStatus { kSetupMatchButEntryBeyondEnd , kSetupMakeClassModeMismatch = -9 , kSetupTreeDestructed = -8 , kSetupNotSetup = -7 , kSetupMissingCounterBranch = -6 , kSetupMissingBranch = -5 , kSetupInternalError = -4 , kSetupMissingDictionary = -3 , kSetupMismatch = -2 , kSetupNotACollection = -1 , kSetupMatch , kSetupNoCheck = 5 , kSetupMatchLeaf = 6 , kSetupMatchBranch }
	Status flags, 0 is good. More...

Public Member Functions
	TTreeReaderArray (TTreeReader &tr, const char *branchname)
	Create an array reader of branch "branchname" for TTreeReader "tr".

T &	At (std::size_t idx)

const T &	At (std::size_t idx) const

iterator	begin ()

const_iterator	begin () const

const_iterator	cbegin () const

const_iterator	cend () const

iterator	end ()

const_iterator	end () const

T &	operator[] (std::size_t idx)

const T &	operator[] (std::size_t idx) const

Public Member Functions inherited from ROOT::Internal::TTreeReaderArrayBase
	TTreeReaderArrayBase (TTreeReader reader, const char branchname, TDictionary *dict)

EReadStatus	GetReadStatus () const override

std::size_t	GetSize () const

std::size_t	GetValueSize () const
	Returns the `sizeof` of the collection value type. Returns 0 in case the value size could not be retrieved.

bool	IsContiguous () const

bool	IsEmpty () const

Public Member Functions inherited from ROOT::Internal::TTreeReaderValueBase
virtual	~TTreeReaderValueBase ()
	Unregister from tree reader, cleanup.

void *	GetAddress ()
	Returns the memory address of the object being read.

const char *	GetBranchName () const

TLeaf *	GetLeaf ()
	If we are reading a leaf, return the corresponding TLeaf.

ESetupStatus	GetSetupStatus () const
	Return this TTreeReaderValue's setup status.

bool	IsValid () const
	Return true if the branch was setup and read correctly.

EReadStatus	ProxyRead ()

EReadStatus	ProxyReadDefaultImpl ()

template<BranchProxyRead_t Func>
ROOT::Internal::TTreeReaderValueBase::EReadStatus	ProxyReadTemplate ()
	Try to read the value from the TBranchProxy, returns the status of the read.

Protected Member Functions
const char *	GetDerivedTypeName () const override

Protected Member Functions inherited from ROOT::Internal::TTreeReaderArrayBase
void	CreateProxy () override
	Create the proxy object for our branch.

bool	GetBranchAndLeaf (TBranch &branch, TLeaf &myLeaf, TDictionary *&branchActualType, bool suppressErrorsForMissingBranch=false)
	Determine the branch / leaf and its type; reset fProxy / fSetupStatus on error.

const char *	GetBranchContentDataType (TBranch branch, TString &contentTypeName, TDictionary &dict, StreamerElementArrayInfo &arrInfo)
	Access a branch's collection content (not the collection itself) through a proxy.

void	SetImpl (TBranch branch, TLeaf myLeaf)
	Create the TVirtualCollectionReader object for our branch.

void *	UntypedAt (std::size_t idx) const

Protected Member Functions inherited from ROOT::Internal::TTreeReaderValueBase
	TTreeReaderValueBase (const TTreeReaderValueBase &)
	Copy-construct.

	TTreeReaderValueBase (TTreeReader reader, const char branchname, TDictionary *dict, bool opaqueRead=false)
	Construct a tree value reader and register it with the reader object.

void	ErrorAboutMissingProxyIfNeeded ()

Detail::TBranchProxy *	GetProxy () const

void	MarkTreeReaderUnavailable ()

void	NotifyNewTree (TTree *newTree)
	The TTreeReader has switched to a new TTree. Update the leaf.

TTreeReaderValueBase &	operator= (const TTreeReaderValueBase &)
	Copy-assign.

void	RegisterWithTreeReader ()
	Register with tree reader.

TBranch *	SearchBranchWithCompositeName (TLeaf &myleaf, TDictionary &branchActualType, std::string &err)
	Search a branch the name of which contains a ".".

Additional Inherited Members
Protected Types inherited from ROOT::Internal::TTreeReaderValueBase
typedef EReadStatus(TTreeReaderValueBase::*	Read_t) ()

Static Protected Member Functions inherited from ROOT::Internal::TTreeReaderValueBase
static const char *	GetBranchDataType (TBranch branch, TDictionary &dict, TDictionary const *curDict)
	Retrieve the type of data stored by branch; put its dictionary into dict, return its type name.

static std::string	GetElementTypeName (const std::type_info &ti)
	Stringify the template argument.

Protected Attributes inherited from ROOT::Internal::TTreeReaderArrayBase
std::unique_ptr< TVirtualCollectionReader >	fImpl

Protected Attributes inherited from ROOT::Internal::TTreeReaderValueBase
TString	fBranchName
	Name of the branch to read data from.

TDictionary *	fDict
	Type that the branch should contain.

bool	fHaveLeaf: 1
	Whether the data is in a leaf.

bool	fHaveStaticClassOffsets: 1
	Whether !fStaticClassOffsets.empty()

TLeaf *	fLeaf = nullptr

TString	fLeafName

bool	fOpaqueRead {false}
	If true, the reader will not do any type-checking against the actual type held by the branch.

Detail::TBranchProxy *	fProxy = nullptr
	Proxy for this branch, owned by TTreeReader.

Read_t	fProxyReadFunc = &TTreeReaderValueBase::ProxyReadDefaultImpl
	! Pointer to the Read implementation to use.

EReadStatus	fReadStatus: 2
	Read status of this data access.

ESetupStatus	fSetupStatus = kSetupNotSetup
	Setup status of this data access.

std::vector< Long64_t >	fStaticClassOffsets

TTreeReader *	fTreeReader
	Tree reader we belong to.

#include <TTreeReaderArray.h>

Inheritance diagram for TTreeReaderArray< T >:

[legend]

Member Typedef Documentation

◆ const_iterator

template<typename T >

using TTreeReaderArray< T >::const_iterator = Iterator_t<const TTreeReaderArray<T>>

Definition at line 230 of file TTreeReaderArray.h.

◆ iterator

template<typename T >

using TTreeReaderArray< T >::iterator = Iterator_t<TTreeReaderArray<T>>

Definition at line 229 of file TTreeReaderArray.h.

Constructor & Destructor Documentation

◆ TTreeReaderArray()

template<typename T >

TTreeReaderArray< T >::TTreeReaderArray	(	TTreeReader &	tr,
		const char *	branchname )

inline

Create an array reader of branch "branchname" for TTreeReader "tr".

Definition at line 233 of file TTreeReaderArray.h.

Member Function Documentation

◆ At() [1/2]

template<typename T >

T & TTreeReaderArray< T >::At ( std::size_t idx )

inline

Definition at line 238 of file TTreeReaderArray.h.

◆ At() [2/2]

template<typename T >

const T & TTreeReaderArray< T >::At ( std::size_t idx ) const

inline

Definition at line 239 of file TTreeReaderArray.h.

◆ begin() [1/2]

template<typename T >

iterator TTreeReaderArray< T >::begin ( )

inline

Definition at line 243 of file TTreeReaderArray.h.

◆ begin() [2/2]

template<typename T >

const_iterator TTreeReaderArray< T >::begin ( ) const

inline

Definition at line 245 of file TTreeReaderArray.h.

◆ cbegin()

template<typename T >

const_iterator TTreeReaderArray< T >::cbegin ( ) const

inline

Definition at line 247 of file TTreeReaderArray.h.

◆ cend()

template<typename T >

const_iterator TTreeReaderArray< T >::cend ( ) const

inline

Definition at line 248 of file TTreeReaderArray.h.

◆ end() [1/2]

template<typename T >

iterator TTreeReaderArray< T >::end ( )

inline

Definition at line 244 of file TTreeReaderArray.h.

◆ end() [2/2]

template<typename T >

const_iterator TTreeReaderArray< T >::end ( ) const

inline

Definition at line 246 of file TTreeReaderArray.h.

◆ GetDerivedTypeName()

template<typename T >

const char * TTreeReaderArray< T >::GetDerivedTypeName ( ) const

inlineoverrideprotectedvirtual

Implements ROOT::Internal::TTreeReaderValueBase.

Definition at line 252 of file TTreeReaderArray.h.

◆ operator[]() [1/2]

template<typename T >

T & TTreeReaderArray< T >::operator[] ( std::size_t idx )

inline

Definition at line 240 of file TTreeReaderArray.h.

◆ operator[]() [2/2]

template<typename T >

const T & TTreeReaderArray< T >::operator[] ( std::size_t idx ) const

inline

Definition at line 241 of file TTreeReaderArray.h.

tree/treeplayer/inc/TTreeReaderArray.h

Classes

Public Types

Public Member Functions

Protected Member Functions

Additional Inherited Members

Member Typedef Documentation

◆ const_iterator

◆ iterator

Constructor & Destructor Documentation

◆ TTreeReaderArray()

Member Function Documentation

◆ At() [1/2]

◆ At() [2/2]

◆ begin() [1/2]

◆ begin() [2/2]

◆ cbegin()

◆ cend()

◆ end() [1/2]

◆ end() [2/2]

◆ GetDerivedTypeName()

◆ operator[]() [1/2]

◆ operator[]() [2/2]